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Core 2 Bacteriology
Core 2 Bacteriology
170
Microbiology
Graduate
10/28/2011

Additional Microbiology Flashcards

 


 

Cards

Term
Staph aureus
Basic properties
Definition
*Gram (+)
*Cocci
*Facultative anaerobe

Location: Normal flora of skin
Term

Staph Aureus

Clinical Presentation (infections)

Definition

Local

1. Skin/subcutaneous: impetigo, cellulitis, folliculitis, furuncles, carbuncles

2. Respiratory: pneumonia (hospital-based)

3. Bone-joint: septic arthritis,

osteomyelitis 

Systemic

1. Acute endocarditis

2. Bacteremia 

Term

Staph Aureus

Clinical Presentation

Toxins

Definition

1. Toxic Shock Syndrome (TSST-1): fever, hypotension, diffuse erythematous rash, system shock.

2. Scalded Skin Syndrome (exfoliatin): blisters, desquamation of skin; massive fluid loss, can lead to shock.

3. Gastroenteritis (enterotoxin B): rapid diarrhea, vomiting; no fever 

Term

S. aureus

Diagnostic Criteria

Definition

1. Grow in clusters

2. Blood culture positive  

3. (+) Catalase test

4. (+) Coagulase test (to diff. S. aureus from other Staphylococci)

5. Rapid growth on non-selective media; aerobic & anaerobic 

6. Produces gold pigment on agar

Term

S aureus

Virulence factors

Definition

Structural

1. Capsule

2. Protein A: binds Fc portion of IgG; prevents opsonization

 

Enzymes

1. Catalase: counteracts 02 free radicals, 

2. Coagulase: causes blood clotting 

3. Hemolysins & Leukocidin: damage PMNs

4. Hyaluronidase: breaks down connective tissue

5. Lipase: breaks down fat

6. Staphylokinase: lyse clots

 

Toxins

1. TSST-1: superantigen; produces cytokine storm

2. Enterotoxin A, B: cause leakage and destruction of endothelial cells.

3. Exfoliatin: serine protease; splits bridges in skin 

Term

S aureus

Treatment & Resistance

Definition

Treatment

1. Penicillinase — resistant penicillins (methicillin, oxacillin, nafcillin)

2. Cefazolin (surgical prophylaxis)

3. Clindamycin

4. Vancomycin (MRSA)

 

Resistance

Resistance to penicillin G and V due to β-lactamase.

 

Increasing resistance to methicillin, nafcillin, and oxacillin (due to mutation in mecA gene)


Term

Staph.

epidermidis


Basic Properties 

Definition

Basic

*Gram (+)

*Cocci

* Facultative

anaerobe

 

Location

Normal flora of

skin, oropharynx

Term

S epidermidis

Clinical Presentation

Definition

Infections

1. Infects patients with indwelling medical devices or immunocompromised. 

2. Bacteremia (through IV line)

3. Endocarditis (of heart valve)

Term

S epidermidis

Virulence factors

Definition

Structural

1. Polysaccharide capsule: allows bacteria to stick to surface of plastics and metals and protects them from phagocytosis.

2. Biofilm: can form biofilms on plastic devices

 

**highly resistant to antibiotics

Term

S epidermidis

 

Lab diagnosis

Definition

Diagnosis

1. Grow in clusters

2. (+) Catalase

3. (-) Coagulase

4. Novobiocin sensitive

 

Note:frequent contaminant in blood cultures (can get false +)

Term

S epidermidis

Tx & Resistance

Definition

Treatment

Vancomycin

 

Resistance

Often resistant to antibiotics used to treat S. aureus such as most penicillins (methicillin, cephalosporins) 

Term

Staph saprophyticus

Basic properties

Definition

 

Basic

Gram (+)

Cocci (clusters)

Facultative anaerobe

non-spore forming

non-motile

 

Location

skin

mucus (oropharynx)

 

Term

S saprophyticus

 

Lab diagnosis

Definition

Diagnosis

1. Grow in clusters

2. (+) Catalase

3. (-) Coagulase

4. Novobiocin resistant

Term

S saprophyticus

 

Clinical presentation

Definition

1. Urinary tract infections(2nd leading cause in young women – second to E. coli)

Term

S saprophyticus

Tx & resistance

Definition

1. Penicillins

2. TMP-SMX (Bactrim)

Term

Strep pyogenes

Basic 

Definition

Gram (+)

Cocci (pairs, chains)

aerotolerant / facultative anaerobe

non-motile

 

Location

Common asymptomatic colonization of upper respiratory tract (pharynx) and skin

Term

S pyogenes

 

Virulence factors

Definition

Structural

1. Capsule (hyaluronic acid)– antiphagocytic

2. Cell wall

     --Lipotechoic acid(binds epithelial cells)

     --M-protein[causes Rheumatic Fever]: alpha-helix of two peptides coded by emm gene; antiphagocytic

     --F-protein: mediates adherence to epithelial cell

Toxins

Enzymes

1. Streptolysin S – oxygen stable; non-antigenic [beta hemolytic activity]

2. Streptolysin O – ASO test looks for Ab; oxygen labile; antigenic  [beta hemolytic activity]

3. Streptokinase – lyses blood clots 

Pyrogenic Exotoxins A-C (See Clinical Presentation) – can cause both scarlet fever and toxic shock syndrome

Term

S pyogenes

 

Lab diagnosis

Definition

Diagnosis

1. Grows in chains

2. (-) Catalase

3. enriched-blood agar; aerobic & anaerobic

4. Lancefield Group A

5. β-hemolytic

6. Bacitracin sensitivity (other forms of Strep are not)

7. (+) PYR [red compound]

8. rapid Strep test (throat) – Group A carb [dimer of GlcNAc and rhamnose] antigen test

9. ASO test looks for Ab to streptolysin O (indicates recent infection)

Term

S pyogenes

 

Clinical Presentation

(Infection)

Definition

LOCAL

1. Skin/soft-tissue

- Erysipelas:superficial skin infection (+subcut.)

- Cellulitis: deeper skin infection [cannot distinguish from Staph. aureus]

-Necrotizing fasciitis: infection of deep subcutaneous tissue [tissue death + high mortality rate] 

2. Respiratory

- Pharyngitis: “strep throat”

- Pneumonia:(not as common as Strep. pneumoniae) 

SYSTEMIC

1. Peurperal fever: post-partum endometritis

2. Bacteremia:infection of blood stream

Term

S pyogenes

Clinical Presentation

(Toxins)

Definition

Toxins

1. Scarlet Fever:  bacteriophage lysogenizes organism(temperate bacteriophage)+ stimulates exotoxin A-C (superantigens) production

-FEVER, RASH (blanches) [trunk/neck]

2. Streptococcal Toxic Shock Syndrome: cellulitis due to exotoxin A -> cytokine storm -> acute fever, shock

Non-suppurative sequelae

1. Acute Rheumatic Fever:  inflammatory changes in heart, joints, blood vessels, skin (subcutaneous nodules)

- ONLY following untreated pharyngitis 

2. Glomerulonephritis

- can follow pharyngitis AND skin infections

-accute inflammation of glomeruli in kidney->hematuria (blood in urine), proteinuria, edema, HYPERTENSION [dark urine, swelling]

Term

S pyogenes

 

Tx & resistance

Definition

 

Treatment

1. Penicillin G

2. Clindamycin (for invasive, necrotizing fasciitis) -> stops M-protein synthesis by inhibiting ribosomes

3.Erythromicin

4.Penicillinase-resistant penicillins (methicillin, oxacillin, nafcillin) --‐ for skin infections where S.aureus or S.epidermidis could be present.

 

Term

Strep. agilactiae


Basic Properties

Definition

Basic

-Gram (+)

-Facultative anaerobe

-non-motile

- diplococci

 

Location

Normal flora of:

-lower GI

-lower GU

Term

S agilactiae

 

Lab dx

Definition

- β-hemolytic

- Group B

- CAMP test

- Gram stain of CSF or urine

- Culture of CSF, urine, blood

Term

S agilactiae

 

Clinical Presentation

Definition

- Neonatalmeningitis(most common)

- NeonatalPneumonia

- NeonatalSepsis

- Sepsis in PREGNANT WOMEN

- increasing incidence in elderly >65,

Term

S agilactiae

 

Treatment

Definition
Penicillin G
Term

Strep pneumoniae

 

Basic properties

Definition

Basic

-Gram (+)

-“lancet” shaped diplococcic

-Facultative anaerobe

-non-motile

Location

-oropharynx (upper respiratory and sinuses)

-children common vectors

Term

S pneumoniae

 

Virulence factors

Definition

Structural

1. Polysaccaride capsule (very important)

-anti-phagocytic

-cause of invasive disease

-vaccine directed at capsule

Enzymes

1. Pneumolysin

-damages alveolar epithelial cells + pulmonary endothelial cells

-cholesterol-dependent chymolysin

-up-regulates IL-6 in airways (inflammation)

Term

S pneumoniae

 

Lab dx

Definition

Diagnosis

1. Grow in pairs (“lancet shaped”)

2. (-) Catalase

3. No Lancefield Group

4. α-hemolytic (leaves green area)

5. Optichin sensitive

Term

S pneumonia

 

Infections

Definition

Infections

Local

1. Pneumonia– most common in community

2. Otitis media– middle ear infection; most common cause

3. Sinusitis– sinus infection; most common cause

Systemic

1. Meningitis(top cause in community—second is N. meningitidis 

2. Bacteremia

Term

S pneumoniae

 

Tx & resistance

Definition

Treatment

1. Penicillins

2. Cephalosporins

3. Vancomycin (for meningitis)

Resistance

*world-wide problems: penicillin and macrolide antibiotic resistance

Vaccine

Pneumovax: vaccine with capsular polysaccharides (conjugated form for children)

Term

Enterococci

(faecalis & faecium)


Basic 

Definition

Basic

-Gram (+)  Diplococci

-Facultative anaerobe

-non-motile

 

-E. faecalis - chains

 

Location

-Normal flora of GI tract

Term

Enterococci

 

Lab dx

Definition

1. Grow in pairs

2. (-) Catalase

3. No Lancefield Group (previously Strep D)

4. γ-hemolytic 

5. Grows in presence of 6.5% NaCl and tolerates 40% bile salts

6. Hydrolyze esculin

Term

Enterococci

 

Clinical Presentation

Definition

Infections

1. Urinary tract infections (nosocomial)

2. Endocarditisgradual/subacute

3. Bacteremia/Biliary tract infections

4. Peritonitis – infection of lining of abdomen due to perforation of bowel

Term

Enterococci

 

Tx & resistance

Definition

Treatment

1. Penicillins (ampicillin + aminoglycoside)

2. Vancomycin (see resistance)

 

Resistance

1. Resistant to Penicillin G

2. Developing resistance to vancomycin 

Term

Corynebacteria diphtheriae


Basic Properties

Definition

Basic

-Gram (+)

-Bacillus

-“clubbing” with angular arrangements (V, W, Y)

-Non-spore forming

-non-motile

-Facultative anaerobe

Location

Respiratory, GU, Skin

Term

Diptheria

 

Virulence factors

Definition

Structural

1. Pseudomembrane: forms in pharynx, serves as base from where it secretes toxins

Toxins

1. Diphtheria toxin: binary toxin with ADP-ribosylating activity that inhibits protein synthesis by inactivating elongation factor EF2

*A subunit: blocks protein synthesis by inactivating EF2

*B subunit: provides entry to heart, nerves

Term

Diptheria

 

Lab dx

Definition

Diagnosis

1. Growth on Loeffler medium(12hrs, stain with methylene blue)

 

2. Black colonies on potassium tellurite agar

 

3. (+) Catalase

Term

Diptheria

 

Clinical presentation

(due to toxin)

Definition

Early symptoms (2-6 days)

1. Pseudomembrane formation in pharynx, malaise, sore throat, anorexia, FEVER

2. Bull-neck: swollen jaw/upper neck

Later symptoms

Severe prostration, rapid pulse, striking pallor, coma and death

Complications

*Myocarditis, Polyneuritis, Parencymatous degeneration, Fat infiltration, Liver Necrosis

Term
Diptheria Treatment
Definition

1. Erythromycin (or Penicillin G)

2. Co-administer antitoxin (DAT from CDC)

3. Immunize with VACCINE (DPT)

Term

Listeria monocytogenes

 

Basic Properties

Definition

Basic

-Gram (+)

- Bacillus (3-5 in chains, cocci/rods)

-Non-spore forming

-MOTILE: Flagella – tumbling motility (@25°C)

-Facultative anaerobe

Location

GI tract (intracellularly in epithelial cells)

Term

Listeria monoctyogenes

 

Virulence factors

Definition

Enzymes

1. Hemolysin: like Streptolysin O – heat labile, antigenic

2. Listeriolysin O: helps bacterial release and dissemination


Toxins

Endotoxin (Lipid A): ONLY gram (+) bacteria with endotoxin

 

Other

H-antigen (flagella)

Term

Listeria

 

Lab dx

Definition

Diagnosis

1. Blood culture using low temperature 2.5°C and differential media

 

2. β-hemolytic

 

3. (+) Catalase

Term

Listeria

 

Clinical presentation

Definition

1. Neonates: 

<5 days: disseminated granulomas, abscesses

>5 days: MENINGITIS (3rd in neonates) + SEPTICEMIA 

2. Pregnant women: bacteremia, septicemia, fetal loss/neonatal meningitis, mild flu, asymptomatic

3. Elderly/immunocompromised: sepsis + meningitis

4. Others: acute febrile (FEVER) gastroenteritis

Term

Listeria

 

Tx & Prevention

Definition

Treatment:

1. Ampicillin +/- aminoglycoside (gentamicin)

2. Penicillin

3. TMP-SMX

 

Prevention

*thoroughly cook food (meats!)

*avoid raw milk

Term

Bacillus anthracis

 

Basic Properties

Definition

Basic

*Gram (+)

* Bacillus

*non-motile

*SPORE FORMING (central | subterminal)

*Facultative anaerobe (aerobe)

Location

Not endogenous

*Reservoir: sheep, goats, cattle, soil

Term

Bacillus anthracis

 

Virulence factors

Definition

Structural [pXO2 plasmid]

Protein capsule: polymer of gamma-D-glutamic acid capsule prevents phagocytosis

Binary Exotoxins [pXO1 plasmid]

A subunits

*Lethal Factor (LF)– Zn2+ protease that destroys MAPK kinase 1 -> disrupts signal transduction -> cell death

*Edema Factor (EF): adenyl cyclase -> ↑cAMP -> increased H2O/ion efflux -> H2O loss + cell death

B subunits

*Protective Antigen (PA): All forms have common “B” subunit. Binds ANTRX1/2 to form heptamer (pore-like structure) -> endocytosis to enter cell

Term

B anthracis

 

Lab dx

Definition

1. Detection of bacteria or toxins via serology or immunoassay

 

2. Gram stain

Term

B anthracis

 

Clinical presentation

Definition

Local

1. Cutaneous anthrax (95% of cases): painless black vesicles/ulcers [5-20% mortality if untreated; <1% if treated]

2. Gastrointestinal anthrax: nausea, vomiting, FEVER, abdominal pain, bloody diarrhea, oropharyngeal infection (pseudomembrane) [50% mortality even with treatment]

Systemic

1. Inhalation anthrax: inhaled spores migrate to lymph system -> germinate to produce lethal toxins -> toxins cause bleeding and destruction of BRAIN,  CHEST ORGANS, etc. -> death [>80% mortality without treatment]

Term

B anthracis

 

Treatment

Definition

1. Oral penicillin (cutaneous and gastrointestinal)

2. Ciprofloxacin [quinolone], Doxycycline (inhalation)

Term

B cereus

 

Basic properties

Definition

*Gram (+)

* Bacillus

*MOTILE

*SPORE FORMING (central)

*OBLIGATE AEROBE

 

Location

Not endogenous, *Generally infects GI tract

Term

Bacillus cereus

 

Virulence factors

Definition

Toxins

Heat-stable (a.k.a., Cereulide or emetic toxin): cyclic peptide ionopore -> disrupts mitochondrial function (causes food poisoning symptoms)

Hemolysin (Hbl) and Nhe: binary toxins; disrupt epithelial cells lining the gut 


Term

Bacillus cereus

 

Lab dx

Definition

Diagnosis

1. Presence of same serotype in feces/vomitus and food samples

2. Presence of large numbers of single serotype associated with food borne illness.

3. Determination of enterotoxin expression via serology/biology tests

4. Motile, aerobic spores

 

*diagnosis usually not performed for this illness

Term

Bacillus cereus

 

Clinical presentation

Definition

Infection (due to toxin)

FOOD POISONING

Early Symptoms (onset: 1-6 hrs; lasts <24 hrs)

Emesis: NAUSEA and VOMITING (no fever)


Later Symptoms (onset: 1-24 hrs; lasts ~24 hrs)

Diarrhea:ABDOMINAL PAIN, CRAMPS, and DIARRHEA (no fever, no vomiting)

OTHER INFECTIONS

*trauma/foreign body entry/indwelling devices (keratitis, endophthalmitis, panophthalmitis; systemic: endocarditis, meningitis, osteomyelitis, pneumonia)

Term

B cereus

 

Treatment & prevention

Definition

1. fluid/electrolyte replacement (because self-limiting, no other treatment)

2. Vancomycin/gentamicin OR clindamycin (severe infections)

 

Prevention

Proper handling of food (especially rice)

Term

Clostridium botulinum

 

Basic properties

Definition

Basic

*Gram (+)

* Bacillus

*SPORE FORMING (subterminal)

*MOTILE

*OBLIGATE ANAEROBE

 

Location

Not endogenous

Term

C botulinum 

 

Virulence factors

Definition

Toxins

Botulinum toxin (BoNT):

*A Domain: protein specific endopeptidases that cause inhibition of vesicular exocytosis (BoNT: cleaves SNARE complex proteins: VAMP/synaptobrevin, syntaxin 1A, SNAP-25)

*B Domain: targets nerve terminals (BoNT: neuromuscular junctions)

-toxin inhibits Ach release

-toxin is HEAT-LABILE

Flagella (H-antigen positive)

Term

C botulinum

 

Lab dx

Definition

Diagnosis

1. Detection of bacterium or toxin in food or patient serum/feces

 

2. differentiate from aerobic spore-forming bacilli by anaerobic culture

Term

C botulinum

 

Clinical presentation

Definition

Infection (due to toxin)

Adults (within 18-24 hours)

Botulism (food poisoning): dysopia [fixed dilated pupils, blurry vision], dizziness, dry mouth, abdominal pain, muscle weakness, paralysis, respiratory failure [NO FEVER]

Neonates: Floppy Baby Syndrome: constipation, flaccid paralysis [NO FEVER]

Wound Botulism (rare): same as adults, except:

*NO GI Involvement

*longer incubation period

*potential FEVER!

Term

C botulinum 

 

Treatment

Definition

Treatment

1. Metronidazole or Penicillin

2. Immediately administer multivalent ANTITOXIN (equine antiserum for adults; BIG-IV for children)

3. Immediate ventilator support (intubation or hyperbaric oxygen) 

Vaccine

Multivalent vaccine available 

Prevention

Heat food (for home canners) because toxin is heat-labile

Term

Clostridium tetani

 

Basic properties

Definition

Basic

*Gram (+)

* Bacillus

*SPORE FORMING (terminal | “clubbed”)

*MOTILE

*OBLIGATE ANAEROBE

 

Location

Not endogenous

Term

C tetani

 

Virulence factors

Definition

Tetanus toxin (TeNT):

*A Domain: protein specific endopeptidases that cause inhibition of vesicular exocytosis (TeNT cleaves VAMP/synaptobrevin)

*B Domain: targets nerve terminals (TeNT: GABAergic or Glycinergic synapses afferent to motoneurons)

 

-toxin inhibits GABA, glycine neurotransmitter release (both inhibitory)

-toxin is HEAT-LABILE

 

Flagella (H-antigen positive)

Term

C tetani

 

Lab dx

Definition

1. Detection of bacterium or toxin in wound or patient serum

*culture bacterium from wound (absence does not negate diagnosis)

 

2. differentiate from aerobic spore-forming bacilli by anaerobic culture

Term

C tetani

 

Clinical presentation

Definition

*incubation: days to weeks 

Early Symptoms

Lockjaw (risus sardonicus), drooling, sweating, irritability, back spasms (opisthotonos) 

Late Symptoms

Same as early symptoms + cardiac arrhythmias, BP fluctuations, profound sweating, dehydration

Term

C tetani

 

Treatment

Definition

Treatment

1. Penicillin G (contraindicated because inhibits GABA) or Tetracycline

2. Immediately administer antitoxin (only neutralizes serum toxin, not intracellular toxin)

3. Supportive care: muscle relaxants + ventilation 

Vaccine

Prevention by immunization against toxin (part of DPT)

Term

Clostridium perfringens


Basic properties

Definition

Basic

*Gram (+) - variable

* Bacillus

*SPORE FORMING (subterminal | ovoid)

*non-motile

*OBLIGATE ANAEROBE

 

Location

Endogenously found in GI tract, as well as outside soil

Term

C perfringens 

 

virulence factors

Definition

Toxins

Various exotoxins (A-B type ENTEROTOXIN; ADP-ribosylase) responsible for NECROSIS

*Θ toxin – β-hemolytic

*α-toxin – α-hemolytic, lecithinase

 

Enzymes

Exoenzymes that cause tissue destruction

Term

C perfringens

 

lab diagnosis

Definition

1. Culture and Gram stain of aspirates, pus

 

2. Blood culture

Term

C perfringens

 

Clinical presentation

Definition

Soft Tissue

1. Cellulitis: exotoxins lead to progressive necrosis, malodorous discharge, hemolysis, toxemia, shock and death

2. Suppurativemyositis

3. Myonecrosis

*all associated with GAS GANGRENE (characterized by crepitus)

Enteric infection

1. Gastroenteritis (self-limiting): Watery diarrhea: associated with food-borne ingestion

*associated with institutional food preparation

Term

C perfringens 

 

Treatment

Definition

1. debridement: immediate surgical removal of infected areas combined with

a.    hyperbaric oxygen

b.   Penicillin G or Clindamycin

 

*mortality high for patients with myonecrosis, suppurative myositis (and all subcutaneous infections)

Term

Clostridium difficile

 

Basic properties

Definition

Basic

*Gram (+)

* Bacillus

*SPORE FORMING (subterminal | ovoid)

*MOTILE

*OBLIGATE ANAEROBE

 

Location

Normal flora of GI tract

Term

C difficile

 

Virulence factors

Definition

Toxins

1. ToxA: enterotoxin

2. ToxB: cytotoxin – causes cardiac edema

Term

C difficile

 

Lab dx

Definition


1. Detect Toxin A and B in cytotoxic assay (immunodetection in patient’s feces)

 

2. Colonoscopy to determine yellowish pseudo-membrane

 

3. isolation of bacterium in patient’s feces

Term

C difficile

 

Clinical presentation

Definition

Infections

Pseudomembranous Colitis: antibiotic-associated diarrhea (with hemorrhagic necrosis) 

*looks like red inflamed mucosa with white exudates

Term

C difficile

 

Treatment

Definition

Treatment

1. Withdraw offending antibiotic (commonly ampicillin or clindamycin or even cephalosporins – both broad spectrum)

 

2. metronidazole (IV or oral) or vancomycin (oral, because IV doesn’t reach colon)

Term

Escherichia coli

 

basic properties

Definition

Basic

*Gram (-)

* Bacillus

*MOTILE (peritrichous)

*Facultative anaerobe

*ferments glucose

*ferments lactose

Location

Commensal GI species

Term

E coli

 

Virulence factors

Definition

Structural

1. O antigen– external-most part of LPS

2. K-1 antigen– capsule, inhibits phagocytosis (seen in neonatal meningitis and bacteremia)

3. H antigen– flagellar, bacterial flagella subunits

4. Pili (fimbriae)

5. Adhesins

6. Siderophore

Toxins

1. LT (heat labile) toxin: adenylate cyclase -> ↑cAMP -> diarrhea

2. ST (heat stabile) toxin: guanylate cyclase -> ↑cGMP -> diarrhea

3. Shiga-like toxin: inactivates 60S ribosome unit -> cell death

Term

E coli

 

Lab dx

Definition

Diagnosis

LACTOSE FERMENTERS:

1. EMB agar (dark purple, black with metallic green sheen)

2. MacConkey agar – pink-purple appearance

3. Culture (blood, urine, CSF, sputum) – can grow at 45.5°C

4. Serology – O, K, H antigens

Term

E coli

 

Clinical presentation

Definition

Infection

Gastroenteritis

1. ETEC – Traveler’s diarrhea. Rice-water consistency. ST, LT toxins.

2. EIEC – invade epithelial cells, produce little Shiga-like toxin, bloodydiarrhea with WBCs (pus), FEVER

3. EPECadherence; small bowel damage

4. EAEC – clumping; fluid transport interference 

5. EHEC – Shiga-like toxin (inhibits 60S). Abdominal pain with bloody diarrhea(no invasion); O157:H7 – hemolytic uremic syndrome 

6. DAEC – invasive, watery diarrhea

1. UTI (pili): adhere to urethra -> bladder (cystitis) -> kidney (pyelonephritis)

2. Bactermia/sepsis (K-antigen): due to lipid A of LPS

3. Neonatal meningitis(K-1): second most common cause

 

Term

E coli

 

Treatment

Definition

Treatment

1. Gastroenteritis: supportive treatment ONLY (fluid/electrolytes + small amt. of glucose)

2. UTI – TMP-SMX, fluoroquinolones

3. Neonatal Meningitis and Bacteremia: 3rd generation cephalosporins (ceftriaxone)

Term

Salmonella

 

Basic properties

Definition

Basic

*Gram (-)

* Bacillus

*MOTILE (peritrichous  flagella)

*Facultative anaerobe

*ferments glucose

*DOES NOT ferment lactose

 

Location

*Infects GI tract – NEVER CONSIDERED COMMENSAL

Term

Salmonella

 

virulence factors

Definition

Structural

1. Adherence factors& invasion factors (invasins)

2. Capsule (Vi): promotes survival from phagocytic catalase and superoxide dismutase

3. Acid tolerance response(ATR) – allows survival in acidic conditions (stomach, phagolysosomes) 

4. H-antigen(flagella)

5.  Siderophores

Term

Salmonella

 

lab dx

Definition

Diagnosis

1. TSI – H2S, blackening at butt of test tube

 

2. No lactose fermentation (EMB and MacConkey  colorless)

 

3. Serotyping (over 2000 serotypes)

 

4. Culturing: blood, stool, urine

Term

Salmonella

 

Clinical presentation

Definition

S. enteritidis

Gastroenteritis: inflammatory diarrhea (tissue invasion – lamina propria)

 

S. typhi/S. paratyphi

Typhoid fever: invade Peyer’s patches -> spread to liver, gall bladder, spleen -> bacteremia [rose spots on abdomen, FEVER, diarrhea, abdominal pain, liver/spleen enlargement]

*can get carrier state

Term

Salmonella

 

treatment

Definition

S. enteritidis

Usually self-limiting without treatment 

S. typhi/paratyphi  fluoroquinolones, chloramphenicol, cephalosporin (e.g., ceftriaxone)

 

Vaccine: available for S. typhi

Term

Vibrio cholerae

 

basic properties

Definition

Basic

*Gram (-) *CURVED bacillus

*MOTILE (single polar flagellum)

*Facultative anaerobe

*OXIDASE POSITIVE

*ferments sucrose

*DOES NOT ferment lactose

Location

*Infects GI tract – NEVER CONSIDERED COMMENSAL

Term

Vibrio cholera

 

virulence factors

Definition

Structural

1. Fimbriae – cell attachment  2. Siderophores  3. H-antigen– flagella

Enzyme

1. Mucinase – adhesion factor, digests mucous to allow attachment

Toxin

1. Cholera toxin

*From CTX phage -> transducible through pili

A-subunit: central, ADPRase -> constitutively active adenylate cyclase -? ↑cAMP à ↑H2O and electrolyte secretion

B-subunit: pentameric 

Term

V cholera

 

Lab dx

Definition

1. Oxidase (+) 

2. No lactose fermentation (EMB and MacConkey  colorless) 

3. TSI – acid slant (sucrose fermenter) and butt without gas

4. TCBS – grows yellow colonies

5. Dark-field microscopy of stool – motile organisms immobilized with antiserum

 

*culture, serological, biochemical testing

Term

V cholera

 

clinical presentation

Definition

Infection

Diarrhea: “rice-water” consistency, leads to hypovolemic shock (and death if not treated)

 

No abdominal pain

NON-INVASIVE

Term

V cholera

 

Tx & prevention

Definition

Oral rehydration (water + electrolytes + glucose) can be sufficient 

Otherwise…

1. Pregnant women: furazolidone

2. Children – TMP-SMX

3. Others – tetracycline 

Prevention

*public hygiene

*Vaccines (killed cell, toxoid [anti-cholera toxin], live attenuated)

**Live attenuated gives “herd immunity”

Term

Pseudomonas aeruginosa

 

basic properties

Definition

Basic

*Gram (-) Bacillus

*MOTILE

*OBLIGATE AEROBE

*OXIDASE POSITIVE

*DOES NOT ferment lactose (or any other sugar)

*Phototrophic

*CAPSULE

Location

Ubiquitous in environment; many organs affected

Term

P aeruginosa

 

virulence factors

Definition

Structural

-Pyocyanin – damages tissue via ROS, blue pus

-Adhesin factorsH-antigen(flagella)

-Biofilm/capsule– problematic in lung infections

Enzymes

-Exoenzyme S– ADP ribosylase ->tissue damage

-Phospholipase C– hemolysin , breaks lipids and lecithin (tissue invasion)

-Elastase – destroys elastin, collagen, fibrin, IgG, IgA, complement, etc. 

Toxins

-Exotoxin A– increased tissue damage, invasion, immune suppression (inhibits EF2)

Term

P aeruginosa

 

lab dx

Definition

1. Oxidase (+) 

2. No lactose fermentation (EMB and MacConkey  colorless) 

3. Blue-green pigment (from blue pyocyanin and yellow fluorescein) 

4. Blood agar – greenish-metallic colonies with FRUITY (grape) smell

Term

P aeruginosa

 

clinical presentation

Definition

Nosocomial

1. Burns and SurgicalSites

2. Endocarditis (catheters, IV lines), Bacteremia, Sepsis

3. Pulmonaryinfections (bronchitis – bronchopneumonia)

4. UTI 

Community

1. Pneumonia (CF patients)

2.  Externalotitismedia

3. Woundinfections (including diabetic foot, diabetic osteomyelitis)

4. Folliculitis

“BE PSEUDO” mnemonic  

Term

 P aeruginosa

 

tx & prevention

Definition

Treatment

1. anti-pseudomonal penicillin + aminoglycoside

a. Ticarcillin + tobramycin

b. Piperacillin + gentamicin 

2. Fluoroquinolones

Resistance to P. aeruginosa rises quickly. Multiple combinations may need to be attempted.

 

Prevention

Sanitation, isolation in hospital

Term

Haemophilus

(influenza, parainfluenza, ducreyi)

 

Basic properties

Definition

Basic

*Gram (-)

*Bacillus (small, pleomorphic)

*non-motile

*Facultative anaerobe

*CAPSULE

 

Location

H. influenza – infects upper respiratory tract

 

H.  ducreyi – infects genitalia 

Term

Haemophilus

 

Virulence factors

Definition

Structural

1. Capsule: antiphagocytic polysaccharide capsule; may contain PRP (polyribitol phosphate)

*6 types: b most virulent

2. Adhesions: pili and non-pilus adhesions (oropharynx colonization)

Enzymes

IgA protease– counter mucosal immunity

Toxins

LPS: can induce violent inflammatory response; impair ciliary functions

Term

Haemophilus

 

Lab dx

Definition

H. influenza

1. Requires X factor (poroporphyrin IX) and V factor (NAD, NADP)

2. Fastidious growth on Chocolate Agar with X, V factors

3. Satellite Phenomenon: H. influenza grows around S. aureus (which produces V factor)

4. Fluorescently labeled antibodies 

5. Positive Quellung test: due to capsule 

H. ducreyi

1. Gram (-) stain from ulcer exudate and pus

2. Only requires X factor

Term

haemophilus

 

Clinical presentation

Definition

 Influenza 

Encapsulated

Meningitis – type b primary cause in infants 3mo to 3yrs old (mental retardation, seizures, deafness)

 Epiglottitis,  Pneumonia, Septicarthritis, Sepsis 

Non-Encapsulated

 OtitismediaSinusitis

 COPD exacerbation

H. ducreyi

Chancroid: painful genital ulcer, associated with unilateral swollen lymph nodes that can rupture (pus)

Term

H influenza

 

Treatment

Definition

H. Influenza

1. 3rd generation cephalosporins 

2. Hib vaccine (type capsule conjugated to diphtheria toxoid) 

3. Passive immunity – mother immunized during pregnancy to passively transfer antibodies in breast milk

Term

H. ducreyi


Treatment

Definition

1. 3rd generation cephalosporins (e.g., ceftriaxone – IM)

 

2. Macrolide (azithromycin or erythromycin)

 

3. Ciprofloxacin (quinolone)

Term

Neisseria Gonorrhea

 

Basic properties

Definition

Basic

*Gram (-)

*Diplococcus (kidney/coffee bean shaped)

*Non-motile

*Facultative anaerobe

Location

*Genitalia

*Conjunctiva (esp. neonates) 

Term

N gonorrhea

 

Virulence factors

Definition

Structural

1. Pili: adherence to epithelial cells; antigenic variation prevents immune response to reinfection

2. Opa protein: attachment and penetration into host [opaque colonies]

3. PorB: prevents fusion of phagyolysosome

Enzymes

1. IgA1 Protease: cleaves IgA; allows transmission through mucous membrane

2. Iron sequestering proteins 

Toxin

LOS endotoxin: stimulates inflammatory response and TNF-α release

Term

N gonorrhea

 

Lab dx

Definition

Microscopy

Gram stain used to diagnose men with purulent urethritis and women with cervicitis – PMNs + gram (-) cocci 

Culture

1. Oxidase (+)

2. Catalase (+)

3. Must grow on selective media (TM VCN – vancomycin, colistin, nystatin) and non-selective media (Chocolate Agar)

4. ONLY FERMENTS GLUCOSE– produces acid

*die in presence of fatty acids, trace metals, dry conditions

*blood culture results only positive during first week of infection 

Term

N gonorrhea

 

Clinical presentation

Definition

(often asymptomatic)

Men:  Purulent discharge, Dysuria

rare: epididymitis, prostatitis, peri-urethral abscesses, orchitis (testes)

Women: Vaginaldischarge, Dysuria, Abdominalpain

PID: endometritis (uterus), salpingitis (fallopian tubes), oophoritis (ovaries)

*complications: sterility, ectopic pregnancy,abscess, peritonitis

*Both men and women:

Pharyngitis, Anorectal gonorrhea, peri-hepatitis (Fitz-Hugh-Curtis syndrome) – can also occur in Chlamydia 

4. Newborns

Purulent conjunctivitis, Gonococcemia , Septic arthritis

*fever, migratory arthralgias, suppurated arthritis, pustular rash on erythematous areas (not head and trunk) 

Term

N gonorrhea

 

Treatment & resistance

Definition

Treatment

1. 3rd generation cephalosporin (CEFTRIAXONE!!)(+ doxycycline for co-infection with Chlamydia)

2. fluoroquinolone + doxycycline

3. Neonates: erythromycin eye drops (prophylactically); ceftriaxone if conjunctivitis developed

RESISTANCE

Plasmid: *temM gene – protects from tetracycline

Chromosomal: mtr locus – efflux pump (removes antibiotics)

*penA locus – mutation that alters PBP2 (reduced affinity for penicillin)

*gyrA, gyrB – makes DNA gyrase resistance to ciprofloxacin 

 

Term

N meningitidis

 

basic properties

Definition

Basic

*Gram (-)

*Diplococcus (kidney/coffee bean shaped)

*Non-motile

*Facultative anaerobe

Location

*Infection begins in nasopharynx (can be asymptomatic)

*Upon entering blood stream, can enter CNS

Term

N meningitidis

 

Virulence factors

Definition

Structural

1. Capsule:(B, C, Y most common in Americas and Europe)

2. Pili: adherence (important for pathogenesis)

3. PorB: interferes with degranulation of neutrophils 

Enzymes

1. IgA1 Protease: cleaves IgA; allows transmission through mucous membrane

2. Iron sequestering proteins

Toxin

LOS endotoxin: contains lipid A – endotoxin activity

Term

N meningitidis

 

Lab dx

Definition

1. Oxidase (+)

2. Catalase (+)

3. Produces acid by metabolizing both glucose and maltose

4. Must grow on selective media (TM VCN – vancomycin, colistin, nystatin) and non-selective media (Chocolate Agar)

5. Present in large numbers in CSF, blood, sputum


1. Capsular antigen tests not sensitive, infrequently used for ID

Term

N meningitidis

 

clinical presentation

Definition

1. Asymptomatic carriage in the nasopharynx

Meningitis

1. Abrupt headache, fever, meningeal signs:

Brudzinski sign: cervical rigidity

Kernig sign: hamstring spasm

2. Can have petechial rash (but more characteristic of meningococcemia)

Meningococcemia (septicemia)

1. Petechial skin lesions (<3mm, no blanching)

2. DIC (disseminated intravascular coagulation) – with shock

3. Waterhouse-Friderichsen syndrome – bilateral adrenal gland destruction (hemorrhage)

4. Fevers, Chills, Malaise, Headache

Term

N meningitidis

 

treatment & prevention

Definition

Treatment

1. Penicillin (drug of choice)

2. If penicillin contraindicated (e.g., allergies):

a. 3rd generation cephalosporin(ceftriaxone)

b. chloramphenicol

Prevention

1. Vaccine (only against A, C, Y, W-135 capsular antigens)

2. Prophylaxis (ceftriaxone, rifampin)

Term

Borrelia recurrentis

 

Basic presentation

Definition

Basic

*Gram (-)

*Corckscrew

*MOTILE (6 axial filaments; periplasmic)

*Microaerophilic

*7-20 periplasmic flagella

Location

Varies

Term

Borrelia recurrentis

 

Virulence factors

Definition

Structural

Antigenic shift: variable expression of outer membrane Vmp lipoproteins allows Borrelia recurrentis to escape opsonization and phagocytosis


Term

B recurrentis

 

Lab dx

Definition

Diagnosis

1. Dark-field microscopy of blood sample (febrile period)

2. Culture on Kelly’s medium (difficult)

3. Stain with analine dyes (Giemsa or Wright)

4. Antibody detection by indirect immune-fluorescence assay (IFA)

Term

B recurrentis

 

clinical presentation

Definition

Infection

Relapsing fever

1. Incubation (3-10 days): chills, fever, headache, muscle aches, shock, convulsions; spirochetes present in blood 

2. Afebrile period (5-6 days): no organism in blood; fever subsides 

3. Relapse (3-10 days): second fever [up to 3-10 recurrences with decreasing severity)

 

1. Splenomegaly, Hepatomegaly

2. Macular rash

3. Jaundice, CNS involvement, fatality

Term

B recurrentis

 

Treatment & prevention

Definition

Treatment

1. Tetracycline 

2. If tetracyclines contraindicated, use Erythromycin

NOTE: antibiotics administered during AFEBRILE period to avoid JARISCH-HERXHEIMER-type reaction

Prevention

1. No vaccine available

2. Avoid exposure to ticks and lice

3. Rodent control 

Term

Borrelia burgdorferi

 

basic properties

Definition

*largest of spirochetes

 

*linear genome with multiple linear and circular plasmids

 

Location

Varies 

Term

Borrelia burgdorferi

 

virulence factors

Definition

Structural

Genome contains linear chromosome with multiple linear and circular plasmids

 

Can survive without iron (uses manganese)

Term

B burgdorferi

 

Clinical presentation

Definition

Infections

Lyme Disease

Early localized stage (stage 1): Erythema chronicum migrans(EMC)

Early disseminated stage (stage 2):   1. Multiple smaller ECM

2. Systemic signs: fatigue, headache, fever, malaise

3. Cardiac: myopericarditis, CHF

3. Neurologic: aseptic meningitis, facial palsies (Bell’s palsy), peripheral neuropathy     4. Arthralgia  5. Nephritis

 

Late stage (stage 3)  1. Chronic arthritis  2. Encephalopathy

Term

B burgdorferi

 

lab dx

Definition

Clinical criteria

a. ECM

b. At least one late manifestation: musculoskeletal, nervous, cardiovascular involvement and lab confirmation

Lab criteria (at least one)

1. isolation of Borrelia burgdorferi

2. ELISA or IFA for IgM or IgG antibodies followed by Western blot

- grows well on Kelly’s medium

- stains well with analine dyes (Giemsa or Wright)

Term

B burgdorferi

 

Treatment

Definition

Stage 1

1. Amoxicillin  2. Doxycycline  3. Cefuroxime (2nd generation cephalosporin)

Stage 2,3

Increased intensity 

Recurrent arthritis, neurological and musculoskeletal diseases:

Penicillin G, cetriazone, cefotaxime

Prevention

2. Wear tight clothing, avoid animal exposure, insect repellant

3. Promptly remove tick (takes long time to transmit spirochete)

Term

Leptospirra interrogans

 

basic properties

Definition

Basic

Spirochete

 

*OBLIGATE AEROBE

*protoplasmic flagella

*terminal HOOKS

*Very small

 

Location

Varies

Term

L interrogans

 

Virulence factors

Definition

Structural

Hooks – allows bacteria to burrow into tissue

Term

L interrogans

 

lab dx

Definition

Diagnosis

1. Culture blood/CSF (first 7-10 days) or urine (after 10 days)  in broth or agar medium

2. Dark-field microscopy (blood)

3. Giemsa stain (thick smear) or silver stain

4. Microscopic agglutination test (MAT) – patient serum agglutinates live leptospires [or ELISA]

5. PCR – nucleic acid probes to detect bacterial DNA in serum, CSF, urine 

*whole blood or urine cultures (Fletcher’s medium) – too long

Term

L interrogans

 

Clinical presentation

Definition

1. Either sub-clinical infection, a mild influenza-like febrile illness with myalgia.

Can remit or progress to:

2. Severe systemic infections (Weill’s Disease) with fever, jaundice, renal and hepatic failure, vasculitis, myocarditis, meningitis, and death

Acute phase (3-10 days)

High fever, headache, nausea, muscle pain (thighs, lower back); progression into liver, kidneys and CNS cause jaundice and hemorrhage 

Afebrile period

Recurrence of fever: fever, leptospires in urine, development of “septic meningitis,” headache, neck pain, nephritis, hepatitis, skin lesions 

Term

Leptospira interrogans

 

Treatment & prevention

Definition

Treatment

1. Penicillin G + Doxycycline (IV)

2. Tetracycline for renal infections

*doxycycline prophylactic in patients exposed to infected animals or water contaminated with urine

Prevention

1. Prevent exposure to matter contaminated with animal urine

2. Reduce contamination by rodent control

3. Vaccinate livestock and pets [distemper-hepatitis-leptospirosis vaccine]

4. Difficult to control completely due to widespread presence in wild

Term

Treponema pallidum

(syphilis)

 

Basic properties

Definition

Gram neg, corkscrew (spirochete)

 

Location:

usually genital areas

Term

Treponema pallidum

(syphilis)

 

lab diagnosis

Definition

1. Cutaneous lesions examined by dark-field microscopy, immunofluorescence, ELISA, silver stain


2. Serologic tests for syphilis (STS)

A. Venereal Disease Research Lab (VDRL)– maximum sensitivity in secondary syphilis

B. Rapid Plasma Reagin (RPR) (tests for Wasserman antibody)


3. Treponemal tests – confirmatory test 

A. FTA-ABS   B. TP-PA    C. Enzyme immune assay


Term

 

Treponema pallidum

(syphilis)

 
Clinical presentation
Definition

PrimaryVERY TRANSMISSIVE:   Chancre

*syphilis disseminated in lymphatics, blood, various organs long before appearance of chancre 

Secondary (2-12 wks after chancre)– VERY TRANSMISSIVE

*AlopeciaFever, weight loss, Lymphadenopathy, Erythematous bilateral rash (palms and soles), Condyloma latum – painless wart-like lesions – packed with spirochetes = CONTAGIOUS

*mucous pouches in mouth, vagina, anus, lesions in bone, liver kidneys

*constitutional symptoms (malaise, fever, etc.) 

Latent (1-40 yrs) – RARELY TRANSMISSIVE (congenital)

CSF exam must be negative to be considered latent 

TertiaryNOT TRANSMISSIVE, rare congenital

*Gummas of skin and bone, Cardiovascularsyphilis, , Neurosyphilis

Term

Treponema pallidum

(syphilis)

 

Treatment & Prevention

Definition

Treatment

1. Benzathine penicillin for primary, secondary, early latent syphilis 

2. Pencillin G for congenital and late syphilis 

(if penicillin contraindicated, use: Tetracycline, or Doxycycline)

 

NOTE: Jarisch-Herxheimer reaction may occur in first few hours after antibiotic therapy of secondary syphilis (not reason to discontinue treatment)

 

Prevention:  Avoid sexual contact with infected individuals

Term

Mycoplasma pneumoniae

 

basic properties

Definition

Basic

*No Gram stain (no cell wall!)

*Mulberry-shaped (other Mycoplasma: fried egg look)

*Motile

*OBLIGATE AEROBE

 

Location

Upper respiratory tract

Term

M pneumoniae

 

Virulence factors

Definition

Structural

1. P1 protein: adhesion factor that destroys cilia of epithelial cells of respiratory tract

2. Sterols in cell membrane: require host cholesterol for membrane formation

 

Metabolic Products

1. Hydrogen Peroxide: H2O2

2. Superoxide: O2

3. Catalase inhibitor

Term

M pneumoniae

 

Lab diagnosis

Definition

1. Culture: sputum, 2-3 weeks, essential for definitive diagnosis 

2. Cold agglutinins: IgM against M. pneumoniae cause RBC agglutination at low temperatures – poor sensitivity, specificity 

3. Complement fixation titer (CF): Ab titer against glycolipid antigens (peak: 4-6 weeks, last years) – poor sensitivity, specificity

4. Enzyme Immuno Assay (EIA): better specificity and sensitivity than CF: Ab to P1 most specific

5. DNA probes and PCR: not yet standardized

Term

M pneumoniae

 

Clinical presentation

Definition

Infections

1. Tracheobronchitis

2. Walking pneumonia (ATYPICAL PNEUMONIA) – fever with dry, non-productive hacking cough (some white sputum)

3. Immunopathogenesis: causes polyclonal T-cell response (“superantigenic response)

Term

M pneumoniae


Treatment & Resistance

Definition

Treatment

1. Tetracycline

2. Macrolide (erythromycin, azithromycin)

3. Fluoroquinolones

 

Resistance

Cell wall inhibitors (penicillins, cephalosporins) do not work because NO PEPTIDOGLYCAL CELL WALL 

Term

R ricketsii

 

Basic properties

Definition

Basic

*weakly Gram (-)

*non-motile

*rod-coccoid shape

*OBLIGATE INTRACELLULAR (need ATP)


Location

Varies

Term

R ricketsii

 

Lab dx

Definition

 


 

1. Micro-immuno-fluorescence (MIF): current standard (need PCR or Western blot to distinguish species)

 

 

 

2. Weil-Felix test: insensitive, low specificity (cross reaction with Proteus); OX-19 (+), OX-2 (+)

 

 

3. Culture: Require BSL-3 conditions

 

Term

R ricketsii

 

Clinical presentation

Definition

Rocky Mountain Spotted Fever

1. Fever: 4-10 days after tick bite

2. Severe headache, muscle pain, lymphadenopathy

3. Rash spreads from extremities to trunk +/- soles and palms

4. Replication in endothelial cells -> vascular damage

5. Rare inoculation eschar

6. encephalitis – leakage from blood vessels of brain

Term

R ricketsii

 

Treatment

Definition


1. Doxycycline

2. Chloramphenicol

Term

Ricketsia prowazekii

 

Basic properties

Definition

Basic

*weakly Gram (-)

*non-motile

*rod-coccoid shape

*OBLIGATE INTRACELLULAR (need ATP)

 

Location

Varies

Term

R prowazekii

 

lab diagnosis

Definition


1. Micro-immuno-fluorescence (MIF): current standard (need PCR or Western blot to distinguish species)

 

2. Weil-Felix test: insensitive, low specificity (cross reaction with Proteus); OX-19 (+) 

Term

R prowazekii

 

Clinical symptoms

Definition

Epidemic typhus

1. Incubation (10-14 days)

2. Abrupt onset fever and headache

3. Rash, spares palms, soles, face

4. Delirium, stupor

5. Gangrene of hands or feet (because of increased risk of clotting)

Bill-Zinsser Disease

1. Reactivation of Rickettsia

2. Mild symptoms

3. NO rash

Term

R prowazekii

 

treatment

Definition

Tetracycline 

Doxycycline

Term
Chlamydia trachomatis
Definition

Basic

*weakly Gram (-)

*Rod shaped

*NO CELL WALL

* OBLIGATE INTRACELLULAR (need ATP)

 

Location

Infects columnar mucosal epithelium (compared to endothelial preference of Rickettsiae)

Term

Chlamydia trachomatis

 

Mechanism of replication

Definition

1. Attachment of elementary body (EB) – infectious, metabolically inactive

2. Upon ingestion [phagocytosis or endocytosis] , there is reorganization into a reticulate body (RB) – noninfectious, metabolically active, becomes inclusion

3. Inclusion body undergoes binary fission

4. There is increased growth and RNA/DNA synthesis (requires host ATP)

5. Elementary bodies (from dividing RB) are liberated via lysis (mediated by protease and intracellular Ca2+)

Term

C trachomatis

 

virulence factors

Definition

LPS – all Chlamydiae have group specific LPS antigen

 

MOMP – unique for each species (serovars)

 

*Resistant to lysozyme (lack peptidoglycan and muramic acid)

*Prevents phagosome-lysosome fusion

Term

C trachomatis

 

lab diagnosis

Definition

1. Molecular amplification tests most sensitive and specific tests available

2. Culture: chick yolk sacs; McCoy cells (specific, but insensitive)

3. Antigen tests (DFA, ELISA) – relatively insensitive

 

*cell culture with specific stains (Giemsa, iodine staining of glycogen inclusions

Term

C trachomatis

 

clinical presentation

Definition

Serovar A-C:  Trachoma: chronic infection -> corneal scarring and blindness (Africa) 

Serovar D-K: urethritis/PID, ectopic pregnancy, neonatal pneumonia, neonatal conjunctivitis, adult conjunctivitis 

Serovar L1-L3:  Lymphogranuloma venereum: papule or ulceration on genitals -> lymph nodes (pus)

Other

2. Reiter’s syndrome: triad of conjunctivitis, urethritis, arthritis [caused by cross-reaction of Ab with joints)

3. Fitz-Hugh-Curtis syndrome – perihepatitis

4. Respiratory infections

5. Atherosclerosis

Term

C trachomatis

 

treatment

Definition

Lymphogranuloma venereum

1. Doxycycline

2. Erythromycin

 

Ocular/Genital Infections

1. Doxycycline

2. Azithromycin

 

Newborn conjunctivitis or pneumonia

1. Erythromycin

Term

Chlamydia psittaci

 

Basic properties

Definition

*weakly Gram (-)

*Rod shaped

*NO CELL WALL

* OBLIGATE INTRACELLULAR (need ATP)

Term

Chlamydia psittaci

 

lab diagnosis

Definition


1. Serological: examine blood for elevated titers of antibodies with complement fixation (CF) and immuno fluorescence tests

2. Intracytoplasmic inclusion bodes DO NOT stain with iodine

Term

C psittaci

 

Clinical presentation

Definition

due to inhalation of bird feces

 

Psittacosis: viral-like, ATYPICAL PNEUMONIA, with fever, dry, non-productive cough

Term

C psittaci

 

Treatment

Definition

1. Doxycycline

2. Erythromycin

Term

Chlamydia pneumoniae

 

Lab diagnosis

Definition

1. Serological: examine blood for elevated titers of antibodies with complement fixation (CF) and immuno fluorescence tests

2. Intracytoplasmic inclusion bodes DO NOT stain with iodine

Term

C pneumoniae

 

clinical presentation

Definition


ATPYICAL PNEUMONIAin young adults (like C. psittaci and Mycoplasma)

Term

C pneumoniae

 

treatment

Definition

1. doxycycline

2. erythromycin

Term

Mycobacterium tuberculosis

 

basic properties

Definition

*Acid fast

*Thin rods

*Non-motile

Catalse +

Weakly gram +

*OBLIGATE AEROBE


Location: LUNGS

Term

M tuberculosis

 

virulence factors

Definition

 Structural

1. Mycosides – mycolic acid bound to carb. (Lipid-rich cell wall)

A. Cord Factor: only found in virulent strains; may be responsible for TNF release

B. Sulfatides: inhibit phagolysosome fusion

C. Wax D: acts as an adjuvant

2. Iron siderophore(Mycobactin)

3. Facultative intracellular growth: can survive and multiple inside macrophages.

Slow growing due to G/C rich DNA

Term

M tuberculosis

 

Lab diagnosis

Definition

1. Stain with Ziehl-Neelsenor Kinyoun 

2. PPD Skin test

>10mm (normal)

>5mm (immuno-compromised/AIDS)

*(+) does not indicate active disease

*false negative in AIDS, malnourished 

3. QuantiFERON test: tests IFN-γ levels in response to addition of TB antigens (specific – comes up negative in patients with BCG vaccine) 

4. Species-specific molecular probes(direct detection with molecular probes insensitive)

Term

M tuberculosis

 

Clinical presentation

Definition

Primary Tuberculosis

1. Asymptomatic

-CASEOUS GRANULOMAS  (type IV hypersensitivity)

- Can get Ghon foci and complexes (may/may not be visible on chest X-ray)

2. Symptomatic

- large caseous granulomas 

-cavitary lesions (visible on chest X-ray)

Secondary Tuberculosis

Pulmonary tuberculosis, Pleural, pericardial infection, Lymph node infection, Kidney, Skeletal, Joints, CNS

Miliary TB (tiny tubercles disseminated throughout body)

Term

M tuberculosis

 

treatment & prevention

Definition

RIPES:

1. Rifampin

2. Isoniazid

3. Pyrazinamide

4. Ethambutol

5. Streptomycin


Prevention

Active surveillance, Prophylactic/Therapeutic intervention, BCG vaccine in endemic regions

Term

Mycobacterium avium

 

Clinical presentation

Definition

Clinically indistinguishable from M. tuberculosis. Common in AIDS patients.

Term

M avium

 

treatment

Definition

Treatment

1. Clarithromycin or azithromycin combined with:

2. Ethambutol

3. Rifabutin

 

*use prophylactic treatment in AIDS patients

Term

Mycobacterium leprae

 

lab diagnosis

Definition

1. Microscopy is sensitive for lepromatous form, NOT tuberculoid form

 

2. Skin testing (lepromin reactivity) required for tuberculoid form

 

3. Skin or nerve biopsy: acid fast bacilli (lepromatous) or granulomas (tuberculoid)

 

*Culture not useful

Term

M leprae

Tuberculoid leprosy

 

clinical presentation

Definition

Increased cellular immune response but decreased humoral antibody response -> granuloma formation -> localized damage to skin and nerves


B. Skin and nerves involved: 1 or 2 superficial unilateral lesions


*few erythematous or hypopigmented plaques with flat centers and raised, demarcated borders; peripheral nerve damage with COMPLETE sensory loss

Term

M leprae

Lepromatous leprosy

 

clinical presentation

Definition

Increased antibody response, but decreased cellular immune response -> increase bacteria in dermal macrophages and Schwann cells of PNS (more infectious and deadly!)


- Organism found everywhere (organ, blood)

- Skin, nerves, eyes and tests involved bilaterally: multiple skin lumps and bumps, leonine facies, saddle nose, peripheral neuropathy, digit absorption, blindness and infertility in men

*many erythematous macules, diffuse nerve involvement, patchy sensory loss

Term

M leprae

 

treatment

Definition

Tuberculoid from (6mo):

1. Rifampin

2. Dapsone

 

Lepromatous form (12mo):

1. Rifampin

2. Dapsone

3. Clofazimine

Term
Otitis media causes
Definition
S pneumonia
H influenzae
Term
Community acquired pneumonia causes
Definition
S pneumniae
Legionella
M pneumoniae
S aureus
H influenzae
Term
Nosocomial pneumonia causes
Definition
P aeruginosa
Kelbisella
Term
UTI causes
Definition
E coli
Proteus
E fecalis
S saprophyticus
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