Term
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Definition
| Gram positive cocci, chains |
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Term
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Definition
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Term
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Definition
gram positive diplococci
present in URT in 1/2 the population
if it invades LRT can cause pneumonia
95% of all bacterial pneumonia |
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Term
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Definition
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Term
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Definition
worms
e.g. Nectator americanus (hookworm) - can bore through intact skin |
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Term
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Definition
| bed bugs, lice, mites, ticks, mosquitos |
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Term
Normal flora of the:
-skin
-conjunctiva
-teeth
-oral mucous membranes |
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Definition
skin: staphylococci (aureus, epidermidis), corynebacteria, other G-, proprionibacterium
conjunctiva: sparse, G+ cocci & G- rods
teeth: Viridans streptococcus (plaque), Strep mutans (caries), lactobacilli (acid formation, dental caries), Actinomyces, anaerobes
oral mucous membranes: streptococci, lactic acid bacteria |
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Term
Normal flora of the:
nasal membranes
pharynx
lower respiratory tract
small intestine
colon
anterior urethra
vagina |
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Definition
nasal membranes: staph (aureus, epidermidis), aerobic corynebacteria ("diphtheroids")
nasopharynx: strep pneumo, Neisseria meningitidis, H. influenzae, G- rods & cocci
-most strains are neither encapsulated nor virulent
-healthy sinuses are sterile
-if respiratory tract epithelium is damaged, may be infected by organisms from the nares
lower respiratory tract: NONE
small intestine: lactics, enterics, enterococci, bifidobacteria
colon: *bacteroides* (abdominal abscesses!), *anaerobes,* lactics, enterics, *Enterococcus faecalis, Clostridium, methanogens
anterior urethra: sparse, staphylococci, corynebacteria, enterics
-Staph epidermidis
-Enterococcus faecalis
-alpha-hemolytic streptococci
-occasionally, E. coli, Proteus, corynebacteria
vagina: lactic acid bacteria during child bearing years; otherwise mixed
-lactobacillus - mutualistic; when killed, make vagina susceptible to Candida infxn
-Group B streptococcus (may infect infant during delivery) |
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Term
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Definition
G- coccobacilli
small, pleomorphic; range in shape from round to short thin rods
a frequent secondary invader to viral influenza |
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Term
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Definition
G- cocci
frequent inhabitants of the upper resp tract, esp pharynx
meningitidis - bacterial meningitis |
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Term
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Definition
the primary bacterium involved in the formation of plaque and dental caries
cell surface enzymes, glycosyl transferase, is involved in the initial attachment of the bacterial cells to the tooth surface and in the conversion of sucrose to dextran polymers (glycans) which form plaque |
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Term
Sputum culture
-from what area are you trying to obtain the culture?
-how do you know that you have an acceptable culture?
-pathogens?
-halos surrounding cocci indicate? |
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Definition
-lower respiratory tract
-few squamous epithelial cells, lots of neutrophils
*make sure you have sputum, not saliva*
-ratio of neutrophils to epithelial cells > 5:1
-bacterial, fungal, mycobacterial (tb)
-Strep pneumoniae (diplococci) |
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Term
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Definition
a mutualistic bacteria of the skin (produce FA that inhibit growth of fungi and yeast)
can become pathogenic, producing disease, acne, if it becomes trapped in the hair follicle |
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Term
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Definition
G+, non-spore-forming, lactic acid bacteria (grouped with actinomyces)
"friendly" gut bacteria
B. bifidum - probiotic - predominant species in the intestine of breast-fed babies, may prevent colonization by potential pathogens |
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Term
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Definition
G+ rods
colonize the bowel
C. perfringens - commonly isolated from feces
C. difficile - may colonize bowel, cause "antibiotic-induced diarrhea" or pseudomembranous colitis |
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Term
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Definition
normal flora of the skin, nose, urethra
can produce biofilms - catheterization, prosthesis - "bacterial bunker," polysaccharide matrix that protects bacteria from opsonization |
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Term
| Staphylococcus saprophyticus |
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Definition
coagulase-negative, G+
the organism that causes the vast majority of UTIs in reproductive-age women who are sexually active; 2nd most common cause of UTI overall
E. coli also causes UTI
Few UTIs are caused by Proteus, Klebsiella, Enterobacter |
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Term
| When do you observe true polymicrobial UTI? |
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Definition
insertion of a long-term urinary catheter or other foreign body (calculi, necrotic tumors)
inadequate emptying of bladder - stagnant pool of urine
fistulous communication b/t urinary tract and GI or female genital tract (e.g. Crohn's disease, transmural inflammation) |
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Term
Urine culture
Significant bacteriuria
#1 cause of UTI? |
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Definition
a quantitative procedure
urine cultures that reveal 10^5 CFU/mL of a single uropathogen have a high probability of true infection in a urine culture
E. coli |
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Term
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Definition
| Very high ID50/LD50, spread occurs easily by fecal-oral route |
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Term
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Definition
Adhesins (glycocalyx, fimbriae, viral capsid, other surface structures)
Capsules - impair phagocytosis
-Strep pneumo, Klebsiella pneumo, H. influenzae, Bacillus anthracis, Y. pestis
M protein: found on cell surface of Strep pyogenes, mediate attachment, helps resist phagocytosis
Waxes: CW of M. tb, helps resist digestion after phagocytosis, type IV hypersensitivity rxn |
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Term
Exoenzymes
Leukocidins
Hemolysins
Coagulase
Bacterial kinase
Hyaluronidase
Collagenase
Necrotizing factors
Lecithinase
Proteases |
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Definition
extracellular enzymes that lyse cells, form or dissolve clots, and dissolve material in tissue
Leukocidins: destroy WBC that are phagocytes; staphylococci, streptococci
Hemolysins: destroy RBC; Clostridium perfringens (gangrene), streptococci
Coagulase: make blood clots, may wall of site of infxn from immune response; some staphylococci
Bacterial kinases: break down clots made by body to isolate infxn; strep & staph
Hyaluronidase: breaks down hyaluronic acid which holds cells together in connective tissue; some strep, gangrene-causing clostridia
Collagenase: breaks down collagen; several clostridia
NF: kill body cells
Lecithinase: destroys plasma membrane of cells
Proteases: break down proteins in tissue |
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Term
Penetration into host cells
Invasins
Cadherin |
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Definition
Invasins: surface proteins that alter actin filaments of host cell cytoskeleton, allow microbes to enter
-Salmonella typhinurium, E. coli
Cadherin: glycoprotein that bridges junctions b/t cells, allowing microbes to move from one cell to another |
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Term
3 mechanisms by which bacterial cells damage host cells:
-direct damage
-toxins (most bacterial damage is carried out this way)
-hypersensitivity reactions |
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Definition
Direct: E. coli, Shigella, Salmonella, Neisseria gonorrhoeae induce cells to engulf them, then metabolize, multiply, kill host cells
-other microbes enter the cell by secreting enzymes or through their own motility
Toxins: fever, CV problems, shock, hemolysis, CNS disruptions
-40% of known bacterial toxins damage eukaryotic cell membranes
-exotoxins are release by G+ & G- bacteria
-endoxins: lipid A, a normal part of the outer membrane that sheds off esp during lysis, only G- & Listeria monocytogenes |
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Term
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Definition
Botulinum toxin: C. botulinum, neurotoxin that inhibits ACh release, causes flaccid paralysis
Tetanus toxin: C. tetani, blocks relaxation of skeletal mm; spasms, lockjaw & convulsions
Diphtheria toxin: Corynebacterium diphtheriae when infected by a phage carrying tox gene, inhibits protein synth in eukaryotes. 2 polypeptides: A (active), B (binding)
Erythrogenic toxins: Strep pyogenes makes 3 cytotoxins which damage blood capillaries, causing a rash
Vibrio enterotoxin: V. cholerae; A (active) & B (binding); A subunit causes epithelial cells to discharge large amounts of fluid & electrolytes
Staphylococcal enterotoxin: Staph aureus; similar to cholera toxin; other enterotoxins cause TSS, scalded skin syndrome |
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Term
Endotoxin
-what is it?
-organisms that release it?
-associated disease states? |
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Definition
part of outer membrane surrounding G- bacteria
lipid A of LPS
effect exerted when G- cells die and CW undergo lysis, releasing endotoxin
chills, fever, weakness, aches, tissue death, shock, death, miscarriage
Salmonella typhi, Proteus, Pseudomonas, Neisseria, E. coli
Fever: LPS is released by digestion in vacuoles, macrophages release IL-1, carried to hypothalamus, induced to release PG, reset body's temp to higher temp
Septic shock: phagocytosis leads to release of TNF, blood capillaries become permeable & release fluids, low BP affects kidneys, lungs, GI tract, sustained bacteremia, cytokine release
-cytokines are responsible for the observed effects of bacteremia |
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Term
Plasmids
-R factors
-other plasmids |
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Definition
Small circular DNA pieces that aren't connected to csome, capable of independent replication
Resistance factors contain antibiotic resistant genes
Contain genes for toxins and pathogenic factors: tetanus toxin, staphylococcal enterotoxin, E. coli enterotoxin (heat-labile), adhesins, coagulase |
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Term
Bacteriophages
-what are they?
-lysogenesis
-produced pathogenic factors? |
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Definition
can incorporate genetic material into csomal DNA and remain latent (lysogeny)
Bacterial cell can change characteristics (lysogenic conversion) and produce toxins/pathogenic factors:
diphtheria toxin
capsule in S. pneumo
Botulinum neurotoxin
Staphylococcal enterotoxin
cholera toxin |
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Term
| Cytopathic effects of viruses (9) |
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Definition
1. inhibit macromolecular synthesis (HSV irreversibly stops mitosis)
2. release of lysosomal enzymes -> cell death
3. inclusion bodies: granules in infected cells, may contain viral parts
4. syncytium: fusion of several adjacent cells to form single giant cell
5. metabolic host changes w/o damaging infected cells, may i/c hormone or protein production
6. interferon production: made by infected cells, protects neighboring cells from infxn
7. antigenic changes on cell surface, causing destruction by immune system
8. csomal changes: breakage & incorporation of oncogenes
9. transformation: abnormal cells that have lost contact inhibition |
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Term
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Definition
routine
tissue rxn (abscess, granulomas), viral inclusions, parasites, some bacteria & fungi |
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Term
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Definition
bacteria
60 sec CV, wash
60 sec iodine, wash
95% alcohol
30 sec safarin, wash |
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Term
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Definition
Ex: Warthin-Starry
blacken all bacteria
Non-gram reactive
Treponema (spirochetes), Bartonella
Weakly G-: Legionella, Helicobacter, Francisella |
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Term
| Periodic acid-Schiff (PAS) or Mucicarmine |
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Definition
| capsule of Cryptococcus neoformans |
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Term
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Definition
Ziehl-Neelsen, Fite (modified, weaker acid)
Mycobacterium tb, Mycobacterium avian complex (need the weaker acid), Nocardia (need weaker acid) |
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Term
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Definition
Gomori methenamine silver (GMS), periodic Acid Schiff (PAS)
Pneumocystis |
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Term
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Definition
Protozoans: malaria, trypanosomes, Leishmania
Helicobacter |
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Term
CSF culture
-disease you're checking for?
-type of culture?
-potential pathogens? |
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Definition
Meningitis
Aerobic culture; fastidious organisms (avoid refrigeration)
Neisseria meningitidis, H. influenzae, Strep pneumo
Cryptococcus neoformans, viruses |
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Term
Wound and abscess culture
-type of pathogens?
-brain, lungs, abdomen abscesses:
-traumatic open wounds:
-surgical wounds:
-human bites:
-dog/cat bites: |
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Definition
most are anaerobic
multiple organisms, mixed (aerobic and anaerobic), usually not a pure colony
-brain, lungs, abdomen abscesses: Bacteroides fragilis
-traumatic open wounds: Clostridium perfringens
-surgical wounds: Staph aureus
-human bites: mouth anaerobes
-dog/cat bites: Pasteurella multocida |
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Term
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Definition
Oral cavity, acid formation, dental caries
L. acidophilus (Doderlain's bacillus), lactic acid formation, prevents colonization of vagina by C. albicans |
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Term
Throat culture
-organisms? |
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Definition
can be hard to interpret
Group A beta hemolytic streptococcus, Strep pyogenes, Neisseria, N. meningitidis |
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Term
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Definition
G+ cocci, chains
NF of the intestine
Euro countries: indicator of fecal pollution
antibiotic resistant, nosocomial pathogen |
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Term
Stool cultures
-when do you obtain?
-organisms?
-special considerations? |
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Definition
only when pt presents with diarrhea
Enterics, Salmonella, Shigella, Campylobacter, E. coli
Yersinia, Vibrio (fastidious)
Gram stain difficult b/c of NF - *don't Gram stain a stool specimen!*
Selective differential aerobic media used for G- bacteria
*O&P* |
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Term
O&P
-what is it?
-pathogens? |
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Definition
stool ova and parasites wet mount and special stained smear for protozoan eggs and trophozoites, helminth eggs
parasites in the colon!
Entameoba histolytica
Giardia lamblia |
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Term
Diagnostic tests for viruses
dx for hepatitis and HIV?
-*HBV* |
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Definition
Virus isolation/cell culture/shell vial
Direct detection of viral antigens on slide treated with virus specific Ab
Nucleic acid hybridization of viral genomes in specimen (indirect)
Viral serology in acute & convalescent sera
serology for dx with hepatitis viruses and HIV
-*HBV: serologic response, first Ab to appear after initial exposure is IgM, indicates an acute infxn* |
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