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Microbiology
Micro for A&D Test II
346
Medical
Graduate
01/23/2010

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Term
Gram positive cocci (2)
Definition
Streptococcus and staphylococcus. Streptococcus is catalase negative (aerotolerant), while staphylococcus is catalase positive (facultative anaerobe)
Term
Gram positive bacilli
Definition
1. Bacillus (catalase +; spore +) 2. Clostridium (catalase +; spore +) 3. Corynebacterium (catalase +; spore -) 4. Listeria (catalase +; spore -) 5. Lactobacillus (catalase -) 6. Mycobacterium (kind of- acid-fast)
Term
How do you differentiate between streptococcus and staphylococcus?
Definition
Streptococcus is catalase negative (aerotolerant) while staphylococcus is catalase positive (facultative anaerobe). Also, streptococci forms chains while staphylococci form clusters
Term
Gram positive cocci that is catalase negative
Definition
Streptococcus
Term
Gram positive cocci that is catalase positive
Definition
Staphylococcus
Term
How do you differentiate btw the different types of streptococcus?
Definition
All are catalase negative. Beta hemolysis= S.pyrogenes and s. agalactiae Alpha= S. pneumoniae and viridens Gamma=enterococci
Term
Gram positive cocci that is catalase negative with beta hemolysis (2)
Definition
1. Strep pyrogenes/Grp A 2. Strep agalactiae/Grp B
Term
Gram positive cocci that is catalase negative with alpha hemolysis (2)
Definition
1. S. pneumoniae 2. Strep viridens
Term
Gram positive cocci that is catalase negative and gamma hemolysis
Definition
Enterococci
Term
How do you differentiate btw the different types of staphylococcus?
Definition
All are gram positive cocci that are catalase positive (facultative anaerobes). Staph aureus is coagulase positive, which the others are coagulase negative (staph saprophyticus and staph epidermidis)
Term
Gram positive cocci, positive catalase test and positive coagulase
Definition
Staphylococcus aureus
Term
Gram positive cocci, catalase positive, coagulase negative (2)
Definition
1. Staphylococcus saprophyticus 2. Staphylococcus epidermidis
Term
Gram positive rod with positive catalase (4)
Definition
Bacillis, corynebacterium, listeria, mycobacterium. All except for mycobacterium (obligate aerobe) are facultative anaerobes. Bacillus and mycobacterium make spores
Term
Gram positive with negative catalase (2)
Definition
Clostridium and lactobacillus **Both also make spores
Term
Gram positive rod with positive catalase and positive spores (2)
Definition
Bacillis and mycobacterium
Term
Gram positive rods with negative catalase that makes spores (2)
Definition
Clostridium and Lactobacillus
Term
Gram positive rod with positive catalase that does not make spores (2)
Definition
1. Corynebacterium 2. Listeria
Term
Group A Streptococci=
Definition
Streptococcus pyogenes. B-hemolysis (like Brp B/agalactiae).
Term
Group B Streptococci=
Definition
Streptococcus agalactiae. B-hemolysis (like Grp A/pyogens)
Term
S. Pyogenes can cause...
Definition
Superficial infections: Strep throat and impetigo. Invasive disease: Scarlet fever, pneumonia, necrotizing fascitis Sequela Diseases: rheumatic rever and acute glomerulonephritis
Term
Strep Pyogenes Virulence Factors
Definition
1. Spreading enzymes (streptokinase and hyaluronidase) 2. M protein (acts as a superantigen and is anti-phagocytic; interfering w/the complement componenet C3b) 3. Hyaluronic acid capsule (anti-phagocytic) 4. Toxins (Streptolysin S/O, Erythrogenic toxin, Exotoxin A, Exotoxin B)
Term
M protein in S. pyogenes
Definition
One of it's virulence factors. Pili-like structure that adheres to the host cell. Acts as a superantigen (elicits a strong immune reaction in host->disease). Anti-phagocytic (interferes w/complement componenet C3b
Term
Streptolysin S and O
Definition
In strep pyogenes; hemolysins that are responsible for strep throat. S is oxygen-stable, and is responsible for the degradation of RBCs and leukocytes in the presence of oxygen (blood agar plates and strep). Streptolysin O is oxygen-labile hemolysin, which binds to cholesterol and is toxic to the heart and other tissues
Term
Streptolysin S
Definition
In S. pyogenes, one of the toxins it produces. Oxygen-stable hemolysin; responsible for blood agar rxn and strep throat. Toxic to tissue, leukocytes, and RBCs
Term
Streptolysin O
Definition
In Strep Pyogenes. Oxygen sensitive/labile hemolysin that binds cholesterol and is toxic to the heart and other tissues
Term
Erythrogenic toxin
Definition
In s. pyogenes. Encoded on lysogenic bacteriophage. A superantigen. Responsible for scarlet fever rash
Term
Exotoxin A
Definition
In strep pyogenes. Causes streptococcal TSS. Superantigen. Works by the same mechanism as staphylococcal TSS.
Term
Exotoxin B
Definition
In strep pyogenes. Causes necrotizing fascitis. 30% mortality
Term
Virulence factors responsible for strep throat
Definition
Streptolysin S and O (hemolysins that destroy cells) in s. pyogenes
Term
Virulence factors responsible for scarlet fever rash
Definition
Erythrogenic toxin in s. pyogenes. This is encoded on a lysogenic bacteriophage (mobile genetic toxin; moves cell to cell). Is a superantigen
Term
Virulence factor responsible for Streptococcal TSS
Definition
Exotoxin A in strep pyogenes. This is a superantigen and works by the same mechanism as staphylococcal TSST
Term
Toxin responsible for necrotizing fascitis
Definition
Exotoxin B in strep pyogenes.
Term
Poststreptococcal sequela diseases
Definition
After an acute reaction, there can be an immunological reaction against an M-protein on s. pyrogenes. Occurs after initial infection, usually as a result of untreated infections. Host cells make Abs against M-antigen left over after insufficient treatment. Abs recognize host cells, too, like heart muscle (rheumatic fever) or glomeruli (acute glomerulonephritis).
Term
Rheumatic fever
Definition
Poststreptococcal sequela disease (following strep pyogenes infection). Antibodies against certain M proteins on strep pyogenes cross-react w/myosin protein in the heart, causing heart valve damage
Term
Acute glomerulonephritis
Definition
Poststreptococcal sequela disease following strep pyogenesinfection. M protein-49 antigen-antibody complexes lodge in glomeruli of kidney
Term
Leading cause of meningitis in adults
Definition
Streptococcus pneumoniae (pneumococci)
Term
How do you distinguish between strep pneumoniae and strep viridans?
Definition
Both are gram positive "cocci," negative catalase and alpha hemolytic. Neither has an antigen on it's surface. But S. pneumoniae forms diplococci (pairs or short chains of cells), while strep viridans forms cocci in chains
Term
Drug of choice for strep pyogenes?
Definition
Penicillin. Little antibiotic resistance
Term
Is strep pyogenes a normal inhabitant of the body?
Definition
No
Term
Is streptococcus pneumonia/pneumococci a normal inhabitant of the body?
Definition
Yes; normal inhabitant of the upper respiratory tract.
Term
Virulence for strep pneumoniae (3)
Definition
1. Capsule (only encapsulated strains are virulent) 2. Secretory IgA protease (destroys IgA antibodies) 3. Pneumolysin (cytolytic toxic that suppresses phagocytosis by interfering w/lysosomes, activates complement)
Term
Secretory IgA protease
Definition
Destroys IgA antibodies. Virulence factor in Streptococcus pneumoniae
Term
Pneumolysin
Definition
Virulence factor produced by streptococcus pneumoniae. Suppresses phagocytosis by interfering w/lysosomes. Cytolytic toxin- makes pores in the cell membrane. Activates complement
Term
Strep agalactiae
Definition
Group B strep. Beta hemolysis, like strep pyogenes. Frequently colonizes the colon and female GU tract. Uncommon cause of invasive disease in adults, but the most common cause of invasive bacterial disease in newborns (neonatal sepsis and meningitis). Normal gut flora
Term
Is strep agalactiae normal gut flora?
Definition
Yes. Frequently colonizes the colon and female UG tract
Term
Most common cause of invasive disease in infants
Definition
Streptococcus agalactiae/Group B strep. Causes neonatal sepsis and meningitis
Term
Tx for strep agalactiae
Definition
Penicillin or ampicillin is drug of choice
Term
Strep mutans
Definition
Same thing as strep viridans. Alpha-hemolytic (like strep pneumoniae), but unlike strep pneumoniae, it forms long chains of cocci. Neither have an antigen on its surface
Term
Strep viridans
Definition
Gram positive cocci without a surface antigen that grows in long chains. Alpha hemolysis. Another name for it is S. mutans. Normal inhabitant on the skin. Rarely causes invasive disease- oral flora and dental plaque. Can cause endocarditis. Live in mouth, and is a problem if they enter the blood stream. Tx: Penicillin
Term
Tx for Strep viridans
Definition
Penicillin.
Term
Is strep viridans part of normal flora?
Definition
Yes. Oral flora, dental plaque. Rarely causes invasive disease, but will if they enter blood stream->endocarditis. Tx with penicillin
Term
Enterococcus
Definition
Gamma hemolysis. Gram positive cocci, but not a streptococci. Normal inhabitant of the gut, and a rare cause of invasive disease in healthy ppl (sometimes a UTI). Usually a nosocomial pathogen, causing an UTI that may lead to endocarditis. Virulence: few classical virulence factors. Highly resistant to antibiotics. Ampicillin use to be drug of choice, but there is more resistance for this now. Also, ampicillin is just static for enterococcus, and this bacteria is hard to clear from the body. If you add aminoglycoside/gentomycin, this will do the trick! (if the strain is not resistant- highly resistant!!). May also use vancomycin and linezolid
Term
Enterococcus tx
Definition
Usually a nosocomial pathogen, causing an UTI that may lead to endocarditis. Highly resistant to antibiotics. Ampicillin use to be drug of choice, but there is more resistance for this now. Also, ampicillin is just static for enterococcus, and this bacteria is hard to clear from the body. If you add aminoglycoside/gentomycin, this will do the trick! (if the strain is not resistant- highly resistant!!). May also use vancomycin and linezolid
Term
Is enterococcus a normal flora?
Definition
Yes. Normal inhabitant of the gut. Rarely causes invasive diseases in healthy ppl, but it is a common nosocomial infection (ppl are given a ton of antibiotics, which allows enterococcus, a highly resistant bacteria, to overgrow). Nosocomial UTIs can develop and may lead to endocarditis
Term
Tx for MRSA in chromosomal mediated resistance in nosocomial pts
Definition
Vancomycin and Linezolid
Term
Tx for MRSA in community acquired, chromosomally mediated resistance
Definition
TMP-SMX, Clindamycin, Vancomycin, Linezolid, Doxycycline
Term
Tx for plasmid-mediated resistance in MRSA
Definition
1. Plasmid mediated resistance (acquires a gene that produces B-lactamase)
a. Inactivate the B-lactamase by adding a B-lactamase inhibitor to penicillin (Ampicillin/Clavulanate=Augmenten)
b. Use a penicillin drug that protects the B-lactam ring (Nafcillin has a chain that physically protects the B-lactam ring)
c. Use a drug not cleaved by B-lactamase (Cephalosporin like Cefazolin or a macrolide like erythromycin, which doesn’t have a B-lactam ring)
Term
Staph aureus is the most common cause of what? (6)
Definition
**Think skin/bone/joint diseases and food poisoning. Impetigo, Cellulitis, Osteomyelitis, septic arthritis, acute endocarditis.
Term
Is staph aureus a normal flora?
Definition
Yes; found in the nose.
Term
Is staph epidermidis a normal flora?
Definition
Yes; found on skin
Term
Virulence factors in S. aureus (11)
Definition
Hyaluronidase and collagenase, coagulase, leukocidins, staphylokinase, lipase, B-lactamase, polysaccharide slime layer, protein A, cytolytic toxins (food poisoning), exfoliative toxin (skin peels off), TSST
Term
Skin/bone/joint infections
Definition
Staphylococcus aureus or B-hemolytic streptococci (Grp A/Strep pyogenes). To cover both, tx with a penicillinase resistant drug- cefazolin or nafcillin
Term
S. epidermidis
Definition
Coagulase negative and novobiocin sensitive. Associated with infections of catheters and implants. Much less likely to cause disease than S. aureus. Endocarditis, infections of catheters and implants when normal flora of the skin moves into the body. Not a great pathogen bc not many virulence factors and no toxins. No B-lactamase
Term
Virulence factors of staph epidermidis (3)
Definition
Not many- not a great pathogen. 1. Hyaluronidase and collagenase 2. Lipase 3. Polysaccharide slime layer
Term
Staphylococcus saprophyticus
Definition
Second leading cause of UTIs. Coagulase negative. Much less likely to cause disease than S. Aureus (only virulence factor is hyaluronidase and collagenase). Novobiocin resistant.
Term
Who does listeria effect?
Definition
Immunocompromised patients: HIV, newborns, transplant patients
Term
How does listeria enter the body?
Definition
Contaminated food or water. Intracellular facultative anaerobe (catalase positive; no endospores)
Term
What does listeria cause?
Definition
Sepsis, meningitis, and GI issues in newborns and immunocompromised individuals (with HIV or transplant pts). This is bc cell-mediated immunity in immune-competent adults detect the presence of listeria in neutrophils and macrophages and destroys them.
Term
Listeriolysin O
Definition
Virulence factor in listeria. Class of hemolysin. Breaks down phagosome before lysosome can fuse with it. allows listeria to live inside cells where the immune system can't see it (in immunocompromised and neonates; healthy immune systems can detect it and these ppl won't get sick).
Term
Virulence of listeria
Definition
Listeriolysin O breaks down phagosome before fusion with lysosome, so that it can live inside cells where the immune system of immunocompromised/neonates cannot see it. It also uses host's actin network to move from cell to cell, evading the host immune system (takes actin from phagocytes, and the actin tail propels listeria from cell to cell)
Term
Tx for listeria
Definition
Ampicillin
Term
Virulence factors of the clostridium spp (5)
Definition
Endospores, multiple exotoxins, collagenase, protease, hyaluronidase
Term
Clostridium tetani
Definition
Clostridium tetani spores are commonly found in soil and animal feces, and when deposited into a wound, they germinate when there is an anaerobic environment (necrotic tissue). From there, Clostridium tetani releases its exotoxin, tetanospasmin. This prevents the release of inhibitory neurotransmitters, causing spastic paralysis. (inhibits exocytosis of inhibitory neurotransmitters)
Term
Clostridium botulinum
Definition
Spores float in the air and can land on food. If the food is not cooked sufficiently, and then is placed in an anaerobic environment (like cans), the clostridium botulinum spores germinate and synthesize the neurotoxin. The toxin blocks release of activating NT acetylcholine, and inhibits components of exocytosis of Ach (VASP, SNAPS). Muscles can't contract->flaccid paralysis. Most potent natural toxin
Term
Clostridium perfringens
Definition
Causes gas gangrene
Term
Clostridium defficile
Definition
Severe diarrhea. Pseudomembranous colitis. Results from long-term antibiotic tx, which depletes natural flora. Can tx with oral vancomycin (doesn't get absorbed, just takes out the C. defficile in the gut)
Term
Eschar lesion
Definition
Caused by cutaneous entry of bacillus anthracis (most common)
Term
Bacillus anthracic portals of entry (3)
Definition
Inhalation (most lethal; inhale endospores), GI (rare), cutaneous (most common, eschar lesion)
Term
How do bacillus and clostridium cause disease?
Definition
By releasing exotoxins. Both are spore formers, but bacillus is a facultative anaerobe while clostridium is an obligate anaerobe
Term
What is the only bacteria to have a capsule composed of protein (poly-D glutamic acid?)
Definition
Bacillus anthracis
Term
Virulence factors for bacilus anthracis (3)
Definition
Endospores, glutamic acid capsule (only bacteria w/protein capsule), anthrax toxin (three parts; cytotoxic- PA, EF, LF)
Term
Anthrax toxin
Definition
Three parts to it. Cytotoxic and multifunctional (three proteins). 1. PA/Protective antigen; B subunit of the AB toxin that is not enzymatically active but carries the other two through the plasma membrane into the cytosol where they catalyze rxns that disrupt normal cellular physiology; enter into phagocytic cells 2. EF: Edema factor; acts as an adenylate cyclace, increasing cAMP and leading to cell water loss and edema c. LF/lethal factor; destroys signaling proteins w/in the cell by protease activity and causes cell death
Term
Edema factor
Definition
Part of anthrax toxin that acts as an adenylate cyclase, increasing cAMP and leading to cell water loss and edema
Term
Lethal factor
Definition
Part of anthrax toxin that destroys signaling proteins w/in the cell by protease activity and causes cell death
Term
Cause of TB and leprosy
Definition
Mycobacterium tuberculosis and leprae (intracellular pathogens)
Term
Mycobacterium diseases
Definition
Acid-fast bacilli; obligate aerobes that make spores. Intracellular pathogens. Either mycobacterium tuberculosis or mycobacterium leprae.
Term
Mycobacterium tuberculosis
Definition
Acid-fast bacilli; obligate aerobe; grows within alveolar macrophages in lungs to cause tuberculosis
Term
Mycobacterium leprae
Definition
Leprosy. Acid-fast bacilli; obligate aerobe; intracellular pathogen that grows w/in neuroglia of peripheral nerve endings; skin cells of fingers, toes, lips
Term
Virulence factors of mycobacterium (2)
Definition
Mycolic acid in cell wall allows cell wall to remain viable for long periods in aerosol drops. Cord factor is a cell wall protein that causes daughter cells to remain attached in parallel alignment (toxic to mammalian cells)
Term
Mycolic acid
Definition
Virulence factor in mycobacterium. Allows cells to remain viable for long periods in aerosol drops.
Term
Cord factor
Definition
Virulence factor in mycobacterium diseases. Cell wall protein that causes daughter cells to remain attached in parallel alignment. Toxic to mammalian cells
Term
Is neisseria meningitidis part of normal flora?
Definition
Yes, in upper airway. Uncommon but devastating invasive diseases: meningitis and sepsis
Term
Is neisseria gonorrhoeae part of normal flora?
Definition
No!
Term
Neisseria morphology
Definition
Gram-negative diplococci that is found intracellularly. Oxidase +
Term
Pathogenic gram negative cocci
Definition
Only one is neisseria
Term
Virulence factors in neisseria meningitides (one that was mentioned in review of the week)
Definition
Polysaccharide capsule
Term
Tx for neisseria meningitidis
Definition
Penicillin or ampicillin. Little drug resistance
Term
Neisseria gonorrhoeae infections
Definition
Urethritis and cervicitis. PID and gonorrhea
Term
Virulence of neisseria gonorrhoeae (2 in ROW)
Definition
Adhesins and antigenic variation (allows repeated episodes of gonorrhea)
Term
Tx for neisseria gonorrhoeae
Definition
Penicillin and fluroquinolone resistance is widespread. Use ceftriaxone.
Term
Gram negative cocci-bacilli
Definition
Haemophilus influenzae
Term
Is haemophilus influenzae part of normal flora?
Definition
Yes; normal inhabitant of the upper respiratory tract
Term
Haemopholus influenzae morphology
Definition
Gram negative, pleomorphic coccobacillus that is very small and requires heme and NAD+ for growth (must live inside cells!)
Term
5 things that haemophilus influenzae cause
Definition
1. otitis media 2. Sinusitis 3. exacerbation of chronic bronchitis 4. Meningitis (now have a vaccine against it; was leading cause of bacterial meningitis in newborns) 5. Pneumonia
Term
Virulence factors in Haemophoilis influenzae (4)
Definition
1. Main one is a polysaccharide capsule, and there are 7 variations on this. Most common pathogenic type is type b (Hib, which is what is vaccinated against). No capsule=less virulent 2. Endotoxin/lipid A 3. Fimbriae 4. IgA protease
Term
Tx for haemophilus influenzae
Definition
40% have plasmid-mediated resistance to penicillins. First line tx is certriaxone
Term
UTI tx
Definition
Mainly caused by gram negatives (Ecoli). Use ciprofloxacin or trimethoprim/sulfa (Bactrim)
Term
Bacterial gastroenteritis
Definition
Inflammation of the stomach or intestines due to the presence of gram negative bacteria. Associated w/contaminated foods or water and poor living conditions. General symptoms include nausea, vomiting, diarrhea, abdominal pain. Dysentery, a severe gastroenteritis, produces loose, frequent stool containing mucus and blood. Examples include cholera, E.coli, Shigellosis, Campylobacter diarrhea, salmonellosis, and typhoid fever
Term
Ecoli
Definition
Facultative anaerobe and a lactose fermentor. Part of normal fecal flora. Can cause UTIs, sepsis, diarrheal syndroms that are either toxin or adhesion mediated. Antigens and exotoxins determine type of disease (5 different types of exotoxins)
Term
Tx for Ecoli
Definition
1. 50% have plasmid mediated resistance to penicillins
2. Use Cephalosporins, aminoglycosides, trimethaprim/sulfa, flouroquinolines
Term
Major cause of gram - sepsis
Definition
Ecoli
Term
Three things that ecoli causes
Definition
UTI, sepsis, and diarrheal syndromes (toxin mediated or adhesion mediated)
Term
P pilli in Ecoli
Definition
Big virulence factor for UTIs. Binds to epithelial cells in UG tract. No p-pilli, no risk for UTIs
Term
Two major virulence factors in Ecoli
Definition
Toxins and p-pilli
Term
Does shingella ferment lactose?
Definition
No, just like Salmonella and unlike EColi
Term
Morphology of shigella
Definition
Gram negative bacillus that is a non-lactose fermentor.
Term
Shigella
Definition
Gram-negative bacillus that is a non-lactose fermentor. SLeading cause of infant mortality worldwide. Signs and symptoms: abdominal cramps, bloody stools, nausea, vomiting, diarrhea. Shiga toxin is an A-B toxin; N-glycosidase that modifies 28S ribosome, thereby inhibiting translation->cells dies->abscesses between endothelial cells->bloody diarrhea
Term
Shigellosis
Definition
Childhood diarrheal disease (dysentery) caused by shigella, a gram negative rod that is a non-lactose fermentor. ABdominal cramps, bloody stool, nausea, vomiting, diarrhea
Term
Types of Salmonella enterica (4)
Definition
Enteritidis and Typhimurium cause gastroenteritis. Typhi and paratyphi cause typhoid fever
Term
Salmonella enterica morphology
Definition
Gram negative rod, non-lactose fermentor. Intracellular
Term
Virulence factors for salmonella (5)
Definition
1. Endotoxin 2. Exotoxin 3. Fimbriae (attachment to mucosal surface) 4. Antigenic variation (change expression of flagellar H antigens) 5. Pathogenicity islands to allow for bacteria-directed endocytosis and to prevent phagosome-lysosome fusion
Term
Salmonella pathogenicity islands
Definition
Chromosomal DNA has these areas. Salmonella Pathogenicity Island 1 (SPI-1) encodes proteins that allow for mammalian cell uptake (it is an intracellular pathogen). Salmonella Pathogenicity Island 2 (SPI-2) prevents phagosome-lysosome fusion
Term
SPI-1
Definition
Salmonella Pathogenicity Island 1. Encodes proteins that allow for mammalian cell uptake/bacterial-directed endocytosis of salmonella.
Term
SPI-2
Definition
Salmonella pathogenicity island 2. Prevents phagosome-lysosome fusion (how they are able to live inside cells
Term
Are shigella and salmonella parts of the normal flora?
Definition
No
Term
Is pseudomonas aeruginosa a normal part of the flora?
Definition
No
Term
Pseudomonas aeruginosa
Definition
Gram-negative strict aerobic bacillus. Ubiquitous environmental microorganism that is resistant to a wide variety of antibiotics and disinfectants. Major nosocomial opportunistic pathogen, especially burn patients and CF patients. Although it is ubiquitous, it is opportunistic and you need to disrupt the skin in order to get sick
Term
2 major classes of ppl to get sick from pseudomonas aeruginosa
Definition
CF patients (problems w/cilia and pseudomonas forms biofilms in lungs) and burn victims
Term
5 Virulence factors in pseudomonas aeruginosa
Definition
1. Fimbriae and adhesions 2. Capsule 3. Pyocyanin (blue green pigment that impairs ciliary function and triggers superoxide formation, killing cells) 4. Elastase 5. Bacteriocins (similar to antibiotics, but directed at microbes that are similar to Pseudomonas)
Term
Pyocyanin
Definition
Blue-green pigment that is a virulence factor in pseudomonas aeruginosa. Impairs ciliary fxn and triggers superoxide formation, killing cells
Term
Bacteriocins
Definition
Similar to antibiotics, but directed at microbes that are similar to Pseudomonas. A virulence factor in pseudomonas aeruginosa
Term
What is the dominant gram negative organism in the colon?
Definition
Bacteroides fragilis. Part of the normal flora
Term
Tx for B fragilis
Definition
Augmentin, meropenem, clindamycin
Term
Oxygen for bacterioides fragilis?
Definition
No- obligate anaerobe
Term
Bacteroides fragilis
Definition
Dominant anaerobic organism of the gut that normally lives there w/o a problem. But if you perforate the bowel, B. frag is an opportunistic pathogen, and it will lead out and cause abscess and septicemia. Part of mixed infections following rupture of hollow organ in gut.
Term
Virulence factors for B. Fragilis (5)
Definition
Endotoxin (lipid A), Enterotoxin (an cause diarrhea), capsule (induces abscess formation), protease (degrades complement components), most make b-lactamase and are resistant to penicillin
Term
Helicobactor pylori
Definition
Gram negative bacilli that lives in the stomachs of 50% of the ppl in the world. Causes gastric and duodenal ulcers (destruction of mucous layer and exposure to H+). Elaborates a urease, which converts urea to bicarbonate, neutralizing stomach acid and allowing the bacteria to live in the stomach
Term
4 virulence factors of Helicobacter pylori
Definition
Urease (converts urea to bicarbonate, neutralizing stomach acid and allowing bacteria to live in the stomach), flagella (allows bacteria to move through mucus and bind epithelial cells; required for pathogenicity), adhesins, toxins
Term
Commensalism
Definition
Microbe benefits; host neither benefits nor is harmed (ex- staphylococcus epidermidis)
Term
Mutualism
Definition
Both microbe and host benefit (ex- E.col)
Term
Primary or overt pathogens
Definition
Cause disease in healthy people. ex- Shigella->bacillary dysentery
Term
2 ways that a microbe can cause disease
Definition
1. Invasion and growth in an inappropriate place->inflammation 2. Production of toxic substances (exotoxins and endotoxins)
Term
Indirect host-to-host transmission (3)
Definition
Living agent (vector; ex- insect), Inanimate object (fomite; ex- doorknob, tabletop); Vehicle (food, water)
Term
Vector
Definition
A living agent that is an intermediate in the transmission process. ex- insect
Term
Fomite
Definition
An inanimate object that is an intermediate in the transmission process. Ex- doorknob
Term
Vehicle
Definition
Food or water that serves as an intermediate in the transmission process. This is thae way that most IDs are passed
Term
Resevoir
Definition
Site where pathogens are maintained as a source of infection. Most cannot live long outside their host (we are major resevoirs). Three types: Animal resevoir, human carriers that are sublinically infected, and non-living resevoir (soil, food, often due to fecal contamination)
Term
Acute carrier
Definition
Individual in incubation period of disease. a type of human resevoir
Term
Chronic carrier
Definition
A person who carries a disease at a subclinical level for an extended period of time. ex- Typhoid Mary
Term
Endemic
Definition
A disease always present in a population, usually at low incidence. ex- STDS
Term
Epidemic
Definition
When an unusual number of ppl in a given area contract a disease w/in a relatively short time
Term
Pandemic
Definition
A widely distributed epidemic; two or more continents. ex- HIV, TB, flu
Term
What do biofilms provide for microbes?
Definition
A protective environment. Shields against antibodies, phagocytic cells and enzymes. Limits access to antibiotics
Term
Three phases of biofilm formation
Definition
1. Attachment (microbes use specialized adhesin proteins and/or glycocalyx to attach to surfaces) 2. Growth (cells multiply and are encased in a polysaccharide material termed the ECM) 3. Detachment (can lead to further colonization w/in the host or microenvironment)
Term
Normal microbiota of the skin
Definition
Primarily gram positive bacteria and fungi associated with sweat glands. Type and number can be affected by age, weather, and personal hygiene
Term
Normal microbiota of the mouth
Definition
The mouth is great bc it is a moist envirnonment w/plenty of nutrients and physiological pH. Must be able to adhere to surfaces due to salivary flow. Viridans Streptococci (alpha-hemolytic; strep mutans)
Term
Normal microbiota of the respiratory tract
Definition
Normally there is staph and strep in the URT. LRT should be axenic (microbes are cleared by antibodies and ciliary action).
Term
Normal microbiota of the UG tract
Definition
Upper regions should be axenic. Urethra is primarily colonized w/facultative anaerobic gram-negative bacteraia (Ecoli)
Term
Where are the three major locations for nosocomial infections?
Definition
UTIs, pneumonias, and bloodstream. These areas are normally azenic!
Term
Sterilization
Definition
Provides complete killing or removal of microbes
Term
Disinfection
Definition
Destroys pathogenic microbes; viable microbes may remain
Term
Bacterial cell wall
Definition
Made of peptidoglycan. Has repeating disaccharides w/4AAs in a side chain extending from each disaccharide. The AA chains of the peptidoglycan covalently bind to other AAs from neighboring chains. This results in a stable cross-linked structure, and the enzyme that catalyzes the formation of this linkage is transpeptidase
Term
Lysozyme
Definition
Enzyme in tears, saliva, and skin. A defense of the body to make sure that the cell wall of bacteria won't stay intact. Lysozyme attacks Beta linkages in the sugar chain of peptidoglycan
Term
N-acetylglucosamine/N-acetylmuramic acid/pentapeptide precursors
Definition
What make up peptidoglycan. Have to get the charged sugars through the hydrophobic membrane in order to reach the cell wall. Must use lipid bactoprenol to do this
Term
Bactopresin
Definition
Disrupts cell wall synthesis by inhibiting Bactoprenol, the lipid that helps transport charged sugars through the cell membrane to the cell wall in order for them to be incorporated into peptidoglycan
Term
Transpeptidation
Definition
Formation of peptide cross-links btw adjacent glycan chains. Catalyzed by PBPs.
Term
Autolysins
Definition
Proteins that cleave the B(1-4) linkage btw NAG and NAM (two of the sugars in the peptidoglycan). This is the same as lysozyme, but it is produced by the cell itself, which aids in cell wall enlargement during growth. Cell wall is constantly being turned over!
Term
Gram Positive Cell walls
Definition
Teichoic and lipoteichoic acids are virulence factors that provide adhesion and a negative charge to the wall. They can induce septic shock and may regulate autolysin function.
Term
Cell walls of mycobacteria
Definition
(TB and leprosy causing). Similar to gram positive. Has mycolic acid residues linked to the peptidoglycan. Mycolic acids are long chain fatty acids that are extremely hydrophobic and are responsible for the acid fast properties of mycobacteria. Causes cells to grow slowly and not stain well. Need a gram stain derivative to recognize mycobacteria
Term
Gram-negative cell wall
Definition
Has lipopolysaccharides embedded in the outer membrane of the cell wall LPS is made up of O and A components. The O component is an external polysaccharide antigen that is organism-specific. The A part is the endotoxin (lipid portion), and this is the toxic part of the LPS. Lipid A/endotoxin can cause fever and shock in patients
Term
O antigens
Definition
Used to figure out the gram negative bacterial species. O antigens are cell wall sugars (part of LPS)
Term
H antigens
Definition
A way to distinguish btw gram negative bacterial species. H antigens are found in the flagella
Term
K antigens
Definition
In gram-negative bacteria, a way to distinguish btw species. K antigens are found in the capsule
Term
Fimbriae and Pili
Definition
Composed of the protein pilin. Numerous hair-like structures over the surface of the cell. Fxn in attachment to surfaces and other cells. ex- Neisseria gonorrhoeae cells use pili to attach to cells in the GU tract; essential forvirulence. ex- E.coli uses P-pili to attach to cells in urinary tract UTI
Term
Chemoheterotrophs
Definition
Most pathogens are chemoheterotrophs. They need chemical compounds for energy (ATP) and organic compounds for C. Our cells are great carbon resources!
Term
Disinfectant
Definition
Acts against microbes on surfaces of inanimate objects non-specifically. Dangerous if used on skin or parenterally
Term
Antiseptics
Definition
Act against microbes non-specifically. Non-toxic to the skin or other tissue. ex-mouthwash
Term
How do disinfectants and antiseptics work? (2)
Definition
Either by disrupting cell membranes (remove or interact w/lipids of the cell membrane; ex- detergents or lipid solvents) 2. Alter proteins irreversibly (act as oxidants, alkylating agents or sulfhydryl-reacting reagents)
Term
Pathogenicity
Definition
Ability of an organism to cause disease. Either is or is not a pathogen (unlike virulence, which is a quantitative measure of pathogenicity)
Term
LD50
Definition
Leathal Dose 50. Measure of virulence. The number of microbes needed to kill half of infected hosts
Term
ID50
Definition
Infectious Dose 50. The number of microbes needed to infect half of the hosts
Term
Four types of adhesins
Definition
Glycocalyx, adherence proteins, lipoteichoic acid, fimbriae (pilli)
Term
Hyaluronidase and collagenase and what two organisms have these enzymes
Definition
Found in strep and staph. Degrade hyaluronic acid, a component fo the ECM and collagen- spreading factors. Help them get through the first protective layer of the epidermis
Term
Coagulase and what has it
Definition
Coagulase helps the bacteria evade the immune system by forming blood clots that provide hiding places for microbes. Staph aureus has it, while staph epid and saprophyticus do not.
Term
Streptokinase and staphylokinase and who has it (2)
Definition
Staphylococcus and streptococcus species have these, which help them digest through blood clots and release microbes, spreading throughout the body
Term
Capsules
Definition
Can be used for attachment to the host cell (as an adhesin). Also are good for eluding macrophages/blocking phagocytosis, as they are composed fo polysaccharides found in the body; not recognized as foreign by the immune system. It is also hard for the phagocytes to engulf the bacteria
Term
Three examples of anti-phagocytic chemicals
Definition
1. Some prevent fusion of lysosome and phagocytic vesicles 2. M protein of Strep pyogenes resists phagocytosis by interfering w/complement component C3b 3. Leukocidins of Staph aureus destroys phagocytic WBCs
Term
A-B toxins
Definition
Act on intracellular targets (neutrotoxins, enterotoxins). Found in Gram positive and gram negative
Term
Cytolytic toxins
Definition
Act on cell surface forming pores in membrane. This disrupts the osmotic balance and leads to host cell death
Term
Typhoid fever, endotoxic shock, UTIs, meningococcal meningitis are all caused by what toxin?
Definition
Endotoxin
Term
Botulinum, tetanus, gas gangrene, diptheria, cholera, staphylococcal food poisoning are all caused by what kind of toxin..
Definition
Exotoxin
Term
Are exo or endotoxins fever producing?
Definition
Endotoxins are fever producing. Exotoxins almost always are not fever producing, except that superantigens do give you a fever
Term
Gram positive cocci that is catalase positive and coagulase positive, presenting with food poisoning
Definition
Staph aureus. May also give skin diseases
Term
Cell wall and membrane in gram + vs -
Definition
Have identical cell walls. Both have periplasm/peptidoglycan layer of cell wall, but this is thick in Gram + and thin in Gram -. The big difference is that gram -s have an outer cell wall, which is where the LPS is located
Term
What are exotoxins vs endotoxins made of?
Definition
Exotoxins are made of protein, and endotoxins are lipopolysaccharide. Therefore, exotoxins are heat labile, unlike endotoxins. Exotoxins sometimes can cause an immune response, but not usually bc they are small and easily overlooked by the immune system. Endotoxins never are attacked by the immune system bc they are not proteins, and that is what the immune system is designed to attacik.
Term
Toxicity of exotoxins vs endotoxins
Definition
Exotoxins are more potent (low LD50)
Term
How widespread is the effect of endotoxin vs exotoxin?
Definition
Exotoxins: specific (not widespread) Endotoxin: non-specifically activate the immune system
Term
Three ways that exotoxins work
Definition
1. membrane disruption (cell dies) 2. Interruption/alteration of cellular enzymes 3. Indiscriminate activation of T cells (superantigens get all sorts of T cells revved up->system goes crazy)
Term
Membrane disruption in exotoxins
Definition
Putting a hole in the membrane kills the cell. Cytolytic; disrupt the phospholipid layer, or form a protein channe. May work by the enzymes phospholipase or amphipathic peptides
Term
Corynebacterium diphtheriae
Definition
Causes diptheria. A gram + rod, + catalase and no spores. Works by secreting an A-B toxin that disrupts protein synthesis and causes cell death in pharynx. B subunit stays on the host cell membrane (specific to the pharynx) whle the A subunit moves inside the cell and binds to EF-2, disabling it. Without EF-2, protein translation cannot continue, and the cell dies. There is a highly effective vaccine against diphtheria, so it is a rare disease in the US. Associated with a pseudomembrane in the pharynx->airway obstruction
Term
Cholera toxin
Definition
Cholera toxin in the gut gets translocated inside the cell and binds to a G protein. This keeps adenylate cyclase on, so you keep making cAMP. This causes channels to open, solutes rush out, followed by water. No tissue damage or cell death, just extreme intravascular water depletion
Term
What does tetanus toxin bind?
Definition
Inhibitory neuron. Prevents it from firing
Term
What are the first signs of botulism?
Definition
Bulbar/CN signs- diploplia
Term
Does the clostridium toxins kill the cells?
Definition
No!
Term
Clinical utility of botulism toxin (3)
Definition
Whenever you want flaccid paralysis. Spasticity, blepharospasm (eyelid twitch), wrinkles
Term
Toxins as superantiens
Definition
Antigen-presenting cells present peptide in MHCII. Only one clone of helper T-cells recognize the antigen-MHC complex. Superantigens bind directly and indiscriminately to the MHC and T-cell receptors (bind the sides, not in the antigen-binding groove). Therefore, they activate many clones of T-cells ->excessive cytokines are produced and you get shock
Term
Two bacteria that cause TSS
Definition
S aureus (staphylococcal TSS and food poisoning caused by the exotoxin) and S pyogenes (GABHS. Exotoxin A is the superantigen that leads to streptococcal TSS)
Term
What toxin causes TSS?
Definition
Superantigens! S. aureus releases a TSS exotoxin that causes toxic shock and food poisoning, while S. pyogenes releases exotoxin A that causes streptococcal TSS
Term
Symptoms of fever, hypotension, diffuse erythroderma, red eyes
Definition
TSS. Multi-system organ involvement. Caused by superantigens produced by S. aureus and S. pyogenes (exotoxin A for this)
Term
symptoms of TSS
Definition
Fever (cytokines being dumped out); hypotension, diffuse erythroderma, red eyes, multi-system organ involvement, skin and mucous membrane changes, fever, myalgias, abdominal pain, weakness, hypotension and oliguria, confusion, headache and vomiting, diarrhea
Term
TSS1
Definition
Released from s. aureus as an exotoxin/superantigen, and causes toxic shock and food poisoning. May be associated w/tampon use. Tx is primarily fluids and pressure support, antibiotics to tx S. aureus. At risk for recurrence; no tampons for a year.
Term
B-lactamase producing organisms (plasmid mediated) (5)
Definition
1. S. aureus (99%!) 2. B. fragilis (over 90%) 3. E. coli (50%) 4. H. influenzae (40%) 5. N. gonorrhoeae (variable)
Term
B-lactamase producing organisms (chromosomally mediated) (2)
Definition
1. Enterobacter 2. Pseudomonas
Term
Sulbactam, tazobactam
Definition
These are B-lactamase inhibitors, just like B-clavulanate. Combined with penicillin
Term
Suicide B-lactamase inhibitors
Definition
Very weak cephalosporin antibiotics. Remove the B-lactamase on a 1:1 basis. B-lactamase recognizes the B-lactam ring, but it cannot let it go. Remove each enzyme, and S. Aureus is now susceptible again to penicillin
Term
Penicillinase resistant penicillin
Definition
Nafcillin. Side chain prevents it from B-lactamase destruction. Used to treat susceptible S. Aureus infections. Excreted unchanged in the urine; doesn't cross the BBB unless meninges are inflamed
Term
What antibiotic is frequently modified by an enzyme?
Definition
Aminoglycoside/gentamycin. The antibiotic is modified so that it is no longer functional. This confers a high level of resistance to aminoglycosides. Plasmid or transposon mediated
Term
Two examples of organisms w/altered antibiotic target sites
Definition
S. pneumoniae and S. aureus
Term
MIC
Definition
Mean amount of drug necessary to inhibit the growth of 50% of the organisms. Increases with an increase in number of PBP mutations in s. pneumoniae and s. aureua
Term
MIC90
Definition
The mean amount of drug necessary to inhibit growth of 90% of the organisms. Increase number of mutations in PBP in S. pneumonia or S. aureus->increased MIC90
Term
MecA+ gene
Definition
In MRSA. Chromosomally mediated resistance. Different from S. pneumoniae chromosomally mediated resistance, bc that can be overcome. Here, you get an alteration in a PBP that can make the cell wall alone. Penicillin can stil bind to normal PBPs, but this mutant doesn't need their help! MRSA is resistant to all B-lactam drugs (Penicillins and Cephalosporins).
Term
S. pneumoniae chromosomally mediated resistance
Definition
Mutations in one or more PBP genes causes increase in MIC. Can be overcome by high doses of either penicillin or cephalosporins (does not make B-lactamase, so it doesn't matter which one you choose).
Term
Macrolide resistance
Definition
Caused by modification of the antibiotic enzymatically or increased efflux
Term
Tetracycline resistance
Definition
Caused by increased efflux
Term
Resistance to TMP-SMX
Definition
Hyperproduction of the target
Term
Three clinically relevant mycobacteria
Definition
M. tuberculosis, M. avium complex, M. leprae
Term
Three encapsulated bacteria
Definition
Strep pneumonia, h. influenza type B, Neisseria meningitides
Term
5 obligate intracellular bacteria
Definition
Salmonella, mycobacterium, listeria, rickettsia, chlamydia
Term
Does mycobacterium tb have a capsule? Is it aerobic or anaerobic? Is it intra or extracellular?
Definition
Intracellular organism that is aerobic and does not have a capsule
Term
Major virulence factors for TB (3)
Definition
Cord factor, able to live intracellularly, and low infective dose
Term
Membrane and wall of mycobacteria
Definition
Cell membrane and peptidoglycan layer like the others, but then they have a thick mycolic acid (60%) and short fatty acid and peptide (40%) layer
Term
Mycolic acid
Definition
Outside of mycobacterium's cell wall (makes up 60% of it). Very hydrophobic and responsible for the acid-fast
Term
Transmission of M. tuberculosis
Definition
Droplets. Aerosols from an infectious person coughing stay suspended in the air w/1-3 organisms (very high infectious dose!) Can hang there and drip down
Term
What 4 things determine the probability that TB will be transmitted?
Definition
1. Infectiousness of the person w/TB 2. Environment in which the exposure occurred 3. Duration of exposure 4. Virulence of organism
Term
Pathogenesis of TB
Definition
Inhale the mycobacterium, and it will not get filtered in the lungs bc it is too small. It is then brought to the lymph nodes by pulmonary macrophages, where T cells should take action. If they do, you develop an immune response and the bacteria is contained. If you are unable to contain it, you will get the disease. TB keeps multiplying inside of the macrophages (is is an intracellular organism). If the T cells are not activated, you will get progressive, systemic disease followed by death (primary pneumonia in children and disseminated disease in both children and adults)
Term
Reactivation/Adult type TB
Definition
Most common. New replication if you get old or immunocompromised. Bacteria were locked away in caseating granulomas but now can replicate. Get an intense inflammatory response as caseating granulomas burst and you get invasion of local tissue and necrosis. Local distruction of tissue->intense inflammatory response. Caseating granulomas are often in the lungs, so bursting them spews bacteria throughout the lungs. This happens when you're older bc T cells stop working as well
Term
Cough, hemoptysis, night sweats, weight loss
Definition
TB
Term
Two major risk factors for developing TB
Definition
HIV and Anti Tumor Necrosis Factor therapy. Also being really young or old (T cells aren't as good then)
Term
PPD
Definition
measures recruitment of macrophages and T cells after injecting M. TB junk. Intra-epidermal, not a good test at all. Interferon assays are much better (take cells from our body and put them into a bath with the antigen. You'll make lots of gamma interfuron if you've seen it before)
Term
Three key components to TB tx
Definition
Never use a single drug, never add a single drug to a failing regimine, and ensure adherence to therapy
Term
How to tx TB
Definition
Resistant to most drugs. Use multiple ones. 1. Isoniazid 2. Rifampin 3. Ethambutol
Term
Isoniazid
Definition
Interferes with mycolic acid synthesis. Associated w/hepatic (get hep A and B) and peripheral nerve toxicity
Term
Rifampin
Definition
Inhibits a DNA-dependent RNA polymerase and is a powerful inducer of the CYP enzymes. Used for lots of things; not very specific, lots of drug-drug interactions
Term
Ethambutol
Definition
Interferes w/mycolic acid synthesis, and has ocular toxicity. Used for TB
Term
Mycobacterium avium
Definition
Environmental pathogen with low virulence. common cause of unilateral adenitis in children. Causes bloodstream infections in patients with AIDS. Lymph node infection in kids, sepsis in adults. Intrinsically resistant to antimicrobial therapy; azithromycin and Rifampin-type drugs
Term
Tx for Mycobacterium avium
Definition
Intrinsically resistant to antimicrobial therapy. Azithromycin and rifampin-like drugs
Term
What does M. leprae effect?
Definition
Grows on colder areas of the body and effects peripheral nerves, skin, and mucous membranes. The clinical spectrum of the disease reflects bacterial proliferation and accumulation at the site of infection, the immunological response, and destruction of nerves. Looks like TB under the microscope. Takes 20-30days to divide, has only been cultured from armadillos (never the lab!)
Term
Lepromatous leprosy
Definition
Diffuse or nodular lesions containing many bacteria. Sensory loss due to nerve damage. Predominant humoral response, little cell mediated immunity!! This is what happens when you don't have a good immune response and you only have humoral mediated immunity. Need T cells
Term
Tuberculoid leprosy
Definition
Few, well-defined lesions. Few organisms (paucibacillary). Predominantly cell-mediated immunity. Spontaneous regression of tuberculoid leprosy occurs in 90% of cases in children. Have cell-mediated immunity, so they clear it (unlike lepromatous)
Term
Tx for leprosy (2)
Definition
Rifampin-like drugs, dapsone
Term
Actinomycetes morphology and how they deal with oxygen
Definition
Anaerobic; gram + and forming long branching filaments; weakly acid-fast
Term
Actinomycosis
Definition
Infection w/actinomycetes, anaerobic gram +, filamentous bacteria. See lumps in belly and neck w/no respect for anatomic boundaries. Chronic, indolent infections in healthy people w/poor definition. Find cervico-facial disease, firm nodules, and sinus tracts. Pus has sulfer granules (mass of filaments). Tx: long course of penicillin
Term
Chronic, indolent cervico-facial disease, firm nodules, and sinus tracts in healthy people
Definition
Actinomycosis. Anaerobic gram + that forms long, branching filaments. Weakly acid-fast. Tx with long courses of penicillin
Term
Nocardia
Definition
Aerobic, gram positive, forming long branching filaments (as opposed to actinomycoses which are anaerobic!). N. Asteroides is found in the soil. Cause chronic infections in the immunocompromised. clinical findings: skin nodules, pnemonia, brain abscess. tx: long course of sulfonamides
Term
Clinical presentation of N. asteroides
Definition
Found in soil and causes Nocardia. This is a mycobacterium. See this in the immunocompromised. See skin nodules, pneumonia, brain abscess. Tx w/a long course of sulfonamides
Term
Tx for N, asteroides/nocardia
Definition
Long course of sulfonamides
Term
Which three classes of antibiotics have a B-lactam ring?
Definition
Penicillin, cephalosporin, carbapenems (meropenum)
Term
How do you tx oral infections?
Definition
Clindamycin
Term
How to you tx strep pyogenes?
Definition
Penicillin
Term
How do you tx strep agalactiae?
Definition
Penicillin or ampicillin
Term
How do you tx enterococcus? First, second, and third line tx
Definition
1. Ampicillin w/aminoglycoside 2. Vancomycin 3. (VRE) Linezolid
Term
How do you tx Strep Viridans?
Definition
Penicillin
Term
How do you tx community acquired pneumonia?
Definition
Assume strep pneumonia, and tx w/azithromycin (assume that it is resistant to ampicillin)
Term
How do you tx hospital acquired pneumonia?
Definition
Azithromycin w/ceftriaxone to get the strep pneumonia. May add vanco for drug-resistant strep pneumo
Term
How do you tx meningitis?
Definition
Ceftriaxone w/vancomycin. Could also give ampicillin to cover listeria
Term
How do you tx HENT infections?
Definition
Augmentin. Two major causes are S. pneumo and H. influenza. H flu is a gram negative, but amoxicillin (and therefore augmentin) will work against it.
Term
How do you tx nosocomial MRSA?
Definition
Vancomycin (IV) and linezolid (oral)
Term
How do you tx community acquired MRSA? (3)
Definition
Bactrim, clindamycin, doxycycline
Term
How do you tx neisseria meningitides?
Definition
Protocol for meningitis is vanc and ceftriaxone, but if you know that its neisseria, use just ceftriaxone
Term
How do you tx neisseria gonorrhoeae?
Definition
Ceftriaxone (one shot). Usually give this w/doxycycline for chlamydia
Term
How do you tx a UTI caused by ecoli? First and second line
Definition
Bactrim is first line, ciprofloxacin is second (don't want to use this bc it is the only oral anti-pseudomonal)
Term
How do you tx typhoid fever?
Definition
Ceftriaxone
Term
How do you tx non-typhoid salmonella?
Definition
Ceftriaxone or ciprofloxacin
Term
Six things that can tx pseudomonas
Definition
Piperacillin, meropenem, gentamicin, ciprofloxacin, ceftazideme (3.5), cefepime (4th)
Term
How do you tx H flu? (2 depending on location)
Definition
1. Amoxacillin/Augmentin for the ear infection 2. Ceftriaxone (and usually vanc, although this won't help for h flu or neisseria) for meningitis
Term
How do you tx syphillis?
Definition
Penicillin
Term
How do you tx lyme disease/borrelia burgdorferi?
Definition
doxycycline
Term
How do you tx mycoplasma pneumonia?
Definition
Azithromycin
Term
How do you tx rickettsia?
Definition
Doxycycline
Term
How do you tx chlamydia?
Definition
Doxycycline (oral only) or azithromycin). Can also give a big shot of ceftriaxone to make sure gonorrheea is gone
Term
What are two drugs you can give for complicated intra-abdominal infections?
Definition
Augmentin or meropenum
Term
What do you use to tx skin and bone infections and for surgical prophylaxis?
Definition
Cefazolin/first generation cephalosporin
Term
What is used to tx pseudomonas aeruginosa, nosocomial infections, and febrile neutropenia?
Definition
Ceftazidime (3.5 generation)
Term
What is the niche of cefepime?
Definition
Serious nosocomial infections, especially in ppl w/o WBNCs. Great gram neg and pos activity, including pseudomonas (like 3.5 ceftazidime). Crosses BBB like ceftazidime and ceftriaxone
Term
Does meropenum cross the BBB?
Definition
Yes. It also has a B-lactam ring, so it is resistant to MRSA and bacteria w/o a peptidoglycan wall
Term
Vancomycin mech of action
Definition
Binds to the substrate in the transpeptidase rxn (D-Ala-D-Ala terminal of the peptidoglycan). Non B-lactam.
Term
Vancomycin niche
Definition
All gram positives but only gram positives. Used for resistant gram positive rxns (MRSA included) and gram positive infections in pts allergic to B-lactams. Also combined w/ceftriaxone in txing meningitis caused by strep pneumonia and neisseria meninigtis in order to cover strep pneumo
Term
Vancomycin toxicity
Definition
Red man syndrome, dose-dependent ototoxicity and nephrotoxicity, especially in the setting of other nephrotoxic drugs (like gentamicin)
Term
Gentamicin mech of action and niche
Definition
Inhibits the 30S ribosomal subunit and works on aerobic gram-negative rods and is synergistic w/cellwall active agents (B-lactamase and vancomycin and carbapens) for gram positive cocci
Term
Toxicity of gentamicin
Definition
Potentially sesvere. Nephrotoxic (especially w/vanc), toxic to auditory and vestibular components of the eighth cranial nerve. Must monitor serum levels and renal fxn.
Term
Is gentamicin IV, oral, or both?
Definition
IV oral. Limited tissue perfusion
Term
Is vancomycin oral or IV or both?
Definition
IV only, good tissue distribution
Term
Tetracycline/doxycycline mech of action and niche
Definition
Inhibits the 30S ribosomal subunit. Works against many gram + and negative bacteria, mycoplasms, chlamydiae, and rickettsiae. Outpt for cutaneous MRSA. Used for rickettsiae, borrelia burgdorferi, chlamydia, mycoplasma
Term
Toxicity of doxycycline
Definition
Diarrhea, vaginal yeast infections, photosensitivity, stains teeth of fetuses and children brown as it binds to calcium. Contraindicated in pregnant women and children under eight
Term
Is doxycycline IV or oral or both?
Definition
Both!
Term
Macrolide example
Definition
Azithromycin
Term
Azithromycin mech of action and niche
Definition
Inhibits the 50S ribosomal subunit. Single dose chlamydia infections, pneumonia, URI (bronchitis), mycoplasma, legionella, s aureus, H flu
Term
What is the toxicity of azithromycin?
Definition
Drug-drug interactions, expecially w/antiarrhythmic drugs. GI upset
Term
Is azithromycin IV or oral or both?
Definition
Both. Excellent oral absorption
Term
What is the mechanism of action of lincosamide/clindamycin?
Definition
Inhibits the 50S subunit
Term
How do you tx penetrating wound infections?
Definition
Aminoglycoside (gentamicin) for the aerobic gram-negatives, and clindamycin for the anaerobes
Term
Is clindamycin IV or oral or both?
Definition
Both! Excellent bioavailability.
Term
Linezolid mech of action and niche
Definition
Inhibits the 50S subunit. Only active against gram positives. Designed for the tx of resistant gram + cocci (MRSA and VRE)
Term
Toxicity of linezolid
Definition
Dose-dependent thrombocytopenis, serotonin syndrome when combined w/SSRIs
Term
Is Linezolid oral or IV or both?
Definition
Both! Claim to fame is that bioavailability is the same in both, so it can be used to orally tx more severe MRSAs than doxycycline can
Term
Trimethoprim/Sulfamethoxazole niche
Definition
UTIs and community acquired MRSA, non-bacterial pathogens such as pneumocystic jiroveci, prophylaxis for immunocompromised pts.
Term
Sulfamethoxazole mech of action
Definition
Structural analogues of para-aminobenzoic acid (PABA) which condenses w/pteridine in the first step of bacterial synthesis of dihydrofolate. We don't synthesize DHT in the process of DNA synthesis
Term
Mech of action of trimethoprim?
Definition
Structurally resembles folic acid and inhibits the enzyme dihydrofolate reductase. Its specificity for bacteria is due to its much greater affinity for bacterial dihydrofolate reductase than for the human enzyme.
Term
Sulfonamide toxicity
Definition
Rashes due to the sulfa component and can precipitate in the urine
Term
Trimethoprim toxicity
Definition
Causes bone marrow suppression or megaloblastic anemia
Term
Example of a fluoroquinolones
Definition
Ciprofloxacin.
Term
Ciprofloxacin mech of action and niche
Definition
Inhibits topoisomerase II (DNA gyrase), inhibiting DNA replication. Only oral tx of pseudomonas (like linezolid, oral bioavailability=IV), UTIs, NOT respiratory infections.
Term
Toxicity of ciprofloxin
Definition
GI, tendonitis, cartilage problems in developing animals (don't give it to kids!), QT prolongation.
Term
Is ciprofloxin oral, IV, or both?
Definition
Both! Oral bioavailability is equal to IV. Good tissue levels
Term
What causes endocarditis? (4)
Definition
Staph aureus (acute onset; most common), s viridans, enterococcus, s epidermidis are slower onset and less commen
Term
[image]
Definition
Streptococcus
Term
[image]
Definition
Neisseria
Term
Chocolate agar
Definition
Contains supplemental nutrients to help support the growth of fastidious organisms (meaning several growth requirements), most classically neisseria species
Term
S aureus hemolysis
Definition
Beta! Just like s pyogenes and grp B strep
Term
MAC agar
Definition
Culture medium designed to support the growth of gram -. Contains bile salts and dies that inhibit the growth of gram +. pH indication: organisms that ferment lactose produce acid which lowers the pH->pink. If it turns this color, it's E.coli for our case
Term
Positive oxidase test
Definition
Means that cytochrome oxidase is present. Used to identify Gram negative microbes (those that carry out aerobic respiration use cytochrome oxidase to transfer electrons). If it turns dark purple, it is positive
Term
Four bugs that use A-B toxins
Definition
Diptheria, cholera, botulism, and clostridium
Term
Cassette of nosocomial MRSA
Definition
Huge, but not very mobile, and this confers a selection advantage when not under antimicrobial pressure. Resistant to many antibiotics
Term
Cassette of community associated MRSA
Definition
Small, very mobile, and little cost to the bacteriuim (can survive without antimicrobial pressure, but is resistant to few antibiotics)
Term
Suicide vs competitive B-lactamase inhibitors
Definition
Suicide- weak cephalosporins Competitive: clavulanate
Term
Gentamicin on Gram +?
Definition
Only if you use a B-lactam with it (wall is too thick for the lg aminoglycoside to get into the cell w/o help)
Term
SIRS
Definition
High probability of progression to sepsis. SIRS+infection=sepsis. Tachycardia, tachypnia, hyper/hypothermia, leukocytosis/leukopenia
Term
Sepsis
Definition
SIRS+infection. Bacterial infection of the blood stream and hypotension, in addition to tachycardia, tachypnea, hyper/hypothermia, and leukocytosis/leukopenia. Lactate up, evidence of necrosis. SIRS secondary to infection
Term
Sepsis vs severe sepsis
Definition
End organ disfunction
Term
APC in sepsis
Definition
Good bc it increases fibrinolysis and inhibits coagulation. Also decreases inflammatory response somehow
Term
What do you give for sepsis due to strep pneumonia?
Definition
APC, ceftriaxone/ciprofloxacin/Vanco, hydrocortisone, pressors, renal failure,
Term
Severe sepsis
Definition
Excess inflammatory response due to infection, inappropriate coagulation, impaired fibrionlysis. This leads to endothelial damage, microvascular dysfunction, impaired tissue oxygenation and organ injury
Term
Capnocytophaga canimorus
Definition
Gram - rod associated w/dog bites that can be a cause of sepsis in post-splenectomy patients
Term
Does chlamydia have a cell wall?
Definition
Yes, but not with peptidoglycan. Use macrolides (azithromycin), doxycycline, or fluoroquinolones (ciprofloxacin). Causes urethritis and pneumonia
Term
Fluoroquinolone ex
Definition
Ciprofloxacin
Term
N. meningitides sepsis tx
Definition
Penicillin or amp
Term
Mycoplasma pneumonia
Definition
No cell wall!Smallest free living bacteria. Tx w/macrolides (Z), doxycycline, fluroquinolones (ciprofloxacin)
Term
Rickettsia
Definition
Arthropod vector. Survives in endothelial cells. Rocky mountain spotted fever. Tx w/doxycycline
Term
Tx for treponema pallidum?
Definition
This is syphillis. Use penicillin
Term
Tx for borrelia burdorferi
Definition
This is lyme disease. Use doxycycline
Term
Does diptheria cause direct cell death?
Definition
Yes! Can't make protein
Term
Normal flora of the skin (3)
Definition
S. epidermidis, S. aureus, S. viridans
Term
Normal flora of the mouth (2)
Definition
S. viridans, actinomyces
Term
Delayed hypersensitivity response in TB
Definition
T cell success at 2-6 weeks. Kill TB laden macrophages, recruit macrophages and activate them (which kill TB). Need the T cells to help direct and coordinate the immune response. 90% of infection controlled and healed by fibrosis (asymptomatic infection or M. tuberculosis infection w/o disease). Will still have a couple little white spots, but these are just walled off infected macrophages
Term
Anti-tumor necrosis factor therapy and TB
Definition
increases your risk for new replication (adult tb) a ton!
Term
Normal gut flora (4)
Definition
Enterococcus, B frag, ecoli, S. agalactiae
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