N. meningitidis
- gram (-) diplococi, catalase (+), oxidase (+)
- polysaccharide capsule, IgA protease, LOS endotoxin
- colonizes URT
- infection often resolves w/o symptoms –> IgG enhanced complement and PMNs defend, leave life-long immunity
- complement deficiency (C6-C9) –> complications
- entry into blood –> meningococcemia (endotoxin –>fever, DIC, petechial rash), meningitis, septic arthritis
- Waterhouse-Friderechsen syndrome
- tetravalent vaccine (give to people in crowded places)
- ferments maltose (M for M)
- DOC: cefotaxamine, ceftriaxone
N. gonorrhoeae
- gram (-) diplococci, catalse (+), oxidase (+)
- IgA protease, pili with millions of variants –> no immunity with reinfection
- choc agar or Thayer-Martin media
- key vignette clues: sexually active PT, urethral/vaginal discharge, arthritis, neonatal opthalmia, gram (-) dipplococcus in neutrophils
- most common cause of urethritis in men with purulent discharge (symptomatic in men)
- tx: ceftriaxone
Treponema pallidum
- spirochete, syphilis, obligate parasite
- primary: painless chancre (“button-like”), infectious –> darkfield microscopy bc antibody titers aren’t high yet
- secondary: rash of palms and soles, patchy alopecia, condyloma lata, infectious –> dx via VDRL
- tertiary: gummas,aortitis, CNS (tabes dorsalis, argyll robertson pupil)
- congenital: stillbirths, malformed
- VDRL and RPR = screening tests for reagin Ab (xrxn with cardiolipin)
- confirm dx with FTA-ABS (immunofluorescence) specific test
- too small to be seen, can’t be cultured. dark-field microscopy
- DOC: PCN G/V
S. aureus
- gram (+) cocci in clusters, catalase (+), coagulase (+), beta hemolytic, ferments mannitol, salt tolerant, produces yellow pigment
- normal in nose, skin
- TSST (superantigen) –> TSS
- exfoliatins –> scalded skin syndrome
- heat-stable enterotoxins –> food poisoning (2-6 hr onset)
- abscesses, impetigo
- secondary pneumonia (bronchopneumonia) –> abcess and cavitary lesions, empyema
- acute endocarditis (IV drug users)
- osteomyelitis (#1 cause)
- DOC MSSA -Nafcillin; MRSA- Vancomycin; VRSA- quinupristin
- no drugs for gastroenteritis bc no bacteria ingested (it’s the toxin doing the damage)
S. epidermis
- gram (+) cocci, catalase (+), coagulase (-), gamma hemolytic (none),
- Novobiocin sensitive (distinguishing feat from S. saprophyticus)
- “plastic adherence” via biofilm
- normal in skin, mouth, gut
- subacute endocarditis in IV drug users
strep pyogenes
- gram (+) cocci in chains, catalase (-), beta hemolytic (complete/clear hemolysis)
- bacitracin S
- M protein– antiphagocytic + certain strains associated with acute glomerulonephritis
- streptokinase, DNAse, hyaluronidase –spreading factors
- pyrogenic exotoxins A-C –**scarlet fever, rash, strawberry tongue **(sandpaper-like rash that blanches under pressure)
- acute suppurative infections: pharyngitis, scarlet fever, pyoderma/impetigo, erysipelas
- non-suppurative sequelae: rheumatic fever (type II hypersensitivity - only after respiratory infection), glomerulonephritis (type III hypersensitivity - after skin OR resp infection)
- DOC: PCN G/V
strep agalactiae
- gram (+) cocci, catalase (-), beta-hemolytic
- group B strep
- bacitracin R
- cause pneumonia, meningitis, and sepsis (mainly in babies)
- # 1 for neonatal meningitis
- CAMP factor
- ampicillin and aminoglycoside
streptococcus pneumoniae
- gram (+) lancet-shaped diplococci, catalase (-), alpha hemolytic, optochin S, lysed by bile
- normal in URT
- capsule (vaccine against this)
- IgA protease
- # 1 cause for adult lobar pneumonia (blood-tinged, rusty sputum)
- # 1 adult meningitis
- # 1 otitis media in kids
- vaccine for elderly (covers 23 serotypes)
- vaccine for pediatrics (covers 7 serotypes)
- DOC: macrolides, ceftriaxone, amoxicillin
strep viridians
- S. sanguis, S. mutans
- gram (+) cocci, catalase (-), alpha hemolytic, optochin resistant
- normal flora of human oropharynx
- dextran (biofilm)-mediated adherence to teeth or damaged heart valve
- dental caries
- subacute endocarditis following dental procedure
- DOC: PCN and aminoglycosides
- live in the mouth bc they are not afraid of- the-chin (op-to-chin R)
E. faecalis
- Enterococcus = group D strep
- Gram (+), catalase (-)
- reservoir: colon, urethra
- bile salt/tolerance allows survival in bowel and gallbladder
- hydrolyze esculin in bile and NaCl (bile esculin agar turns black)
- UTI and biliary tract infections
- infective endocarditis following GI/GU sx on pre-existing damaged heart valve
- TX: aminoPCN, drug-resistance ( ie: VRE)
Bacillus anthracis
- gram (+) rod, spore forming, aerobic
- peptide (poly-D-glutamate) capsule
- anthrax toxin: protective antigen, lethal factor, edema factor (activate AC –> cAMP –> Cl efflux and H2O follows)
- animal contact
- cutaneous anthrax: painless skin ulcer, black eschar, striking local edema
- pulmonary anthrax: woolsorter’s disease pneumonia (inhalation of spores) –hemorrhagic mediastinitis (widening of mediastinum Xray), bloody pleural effusions, septic shoch, death
- key clues: contact with animal hides or postal worker; eschar or life-threatening pneumonia
- DOC: ciprofloxacin or doxycycline
Bacillus cereus
- gram (+) rod, spore-forming, aerobic, motile
- heat-stable exotoxin: vomiting
- heat labile toxin: non-bloody diarrhea
- fried rice (reheated) – heating allows for spore germination
- food poisoning (2-18 hrs)
- symptomatic Rx
Clostridium tetani
- gram (+) rod, spore forming, anaerobic, motile
- exotoxin: tetanospamsin carried intraxonally to CNS –> blocks inhibitory NTMs GABA and Glycine –>unopposed excitation –> spastic paralysis
- tetanus: risus sardonicus, opisthotonus
- key clues: dirty puncture wound, rigid paralysis
- DOC: hyperimmune globulin, PCN + spasmolytic
- Toxoid vaccine
clostridium botulinum
- gram (+) rods, spore forming, anaerobic, motile
- heat-labile neurotoxin that blocks ACh release at NMJ –> flaccid paralysis
- adults: canned food poisoning – veggies and fish (ingestion of preformed toxin)
- infants: floppy baby syndrome from eating honey (ingestion of spores– GI tract can handle spores yet)
- trivalent antitoxin
- DOC: antitoxin + PCN
Chlamydia trachomatis
- non-gram staining intracellular pathogen (can’t make ATP)
- rugged, infectious elementary bodies attach to cell –> endocytose –> unpack reticulate bodies (replicative form) –> inclusion bodies
- serovars A,B,C cause blinding trachoma
- serovars L1-3: lymphogranuloma venereum
- serovars D-K: STD(#1 bacterial STD)–> urethritis, cervicitis, PID, inclusion conjunctivitis/pneumonia in babies
- DX: iodine staining reveals intrapithelial inclusion bodies
- Reiter syndrome: urethritis, conjuctivitis, arthritis
- tx: Doxycycline (except pregnant women)
- ” PMNs but no organism on gram stain”
chlamydophila
- C. pneumoniae: atypical pneumonia (sputum with intracytoplasmic inclusions)
- C. psittaci: atypical pneumonia (exposure to parrots)
- DOC: macrolides
Clostridium perfringens
- gram (+) rod, spore-forming, anaerobic
- alpha toxin = lecithinase/phosphlipase –> myonecrosis (gas gangrene) and hemolysis
- enterotoxin
- stormy fermentation
- double-zone hemolysis
- egg yolk agar
- normal in colon
- food poisoning
- high mortality
- DOC: PCN G +/- Clindamycin and debridement
Corynebacterium diptheriae
- gram (+) club-shaped rod, non-spore forming, aerobic
- metachromatic granules
- tellurite: black colonies
- diptheria via exotoxin encoded by beta-prophage –> inhibits protein synthesis via ADP-ribosylation of EF-2
- pseudomembranous pharyngitis, myocarditis, arrhythmias
- Elek test for toxin
- toxoid vaccine prevents diptheria (part of DTP, DTaP)
- DOC: 1) antitoxin (passive immunity) 2)erythromycin 3)DPT (active immunity)
- ABCDEFG: ADP ribosylatriion, Beta-prophage, Corynebacterium (club), Diptheria, Elongation Factor 2, Granules
Actinomyces israelii
- gram (+) branching rod, anaerobic
- sulfur “granules” in exudates from sinus tract (draining abscesses)
- normal in mouth and female GU tract
- cervicofacial (lumpy jaw) via dental trauma or poor oral hygeine
- pelvic infection via IUD
- solitary brain abscesses
- cervicofacial mycetoma (“lumpy jaw”)
- Rx: PCN plus drainage
trichomonas vaginalis
- motilite flagellated protozoa
- vaginitis (mainly affects women)
- strawberry cervix
- odorous, foamy/frothy discharge
- dyspareunia, urge to urinate and dysuria
- post-coital bleeding
- excessive or prolonged menses
- dx: culture, antigen detection, DNA probe or wet mount
- usually tx presumptively (if uncertain send wet mount)
- tx is the same for BV and trich; need to tx partner if trich
bacterial vaginosis
- disturbance of normal vaginal bacterial microflora (not really an STI, but women are prone to getting it with sex)
- caused by decreased vaginal concentration of lactobacilli
- thin, milky-white, “fishy” odorous discharge
- can lead to pregnancy complications, PID
dx: Amsel’s Criteria (at least 3/4 are positive)
- KOH whiff test (+) for fishy odor
- clue cells
- vaginal pH > 4.5
- homogenous, non-inflammatory discharge
vaginal candidiasis
- overgrowth of the fungus Candida (not really an STI)
- females: very itchy, “cottage cheese-like” discharge (thick, clumpy, white)
- largely a clinical dx (no lab test performed)
- KOH wet mount: pseudohyphae or spores
Nocardia asteroides
- gram (+) branching rod, aerobic (distinguishing feat from A. isrealii)
- urease (+)
- partially acid-fast (distinguishing feat. from A. israelii)
- no toxins or virulence factors
- cavitary bronchopulmonary disease in immunosuppressed –> hematogenous spread to form brain abscesses
- cutaneous/subcutaneous if traumatic implantation from soil –> cellulitis –> draining SQ abcesses with granules (mycetoma)
- DOC: sulfonamides
mycobacterium
- acid fast rods
- oblitage aerobes
- waxy cell wall with high concentration of lipids (mycolic acids) that make them resistant to desiccation and many chemicals
mycobacterium tuberculosis
- acid fast, obligate aerobe
- cord factor (mycolate lipid) inhibits WBC migration; disrupts mitoch resp and ox phos
- sulfatides inhibit phagosome-lysosome fusion
- niacin (+), heat sensitive catalase: (+) at 37 and (-) at 68 degrees C
- delayed hypersensitivity and CMI –> granulomas and caseation (no exo/endotoxins – damage done by immune system)
- primary TB: replicate in alveolar macros and kill macros until CMI is est–> Ghon focus –> asymptomatic but +PPD
- macros transport to LNs –> Ghon complex –> most ppl heal w/o disease (latent/dormant infection)
- reactivation via immunosuppression –> apex of lung
- extrapulmonary: meningitis, Pott disease, scrofula, GU TB
- drug resistance
- slow growing Lowenstein-Jensen medium
- PPD indicates exposure, not active TB
- DOC: isoniazid + rifampin + pyrazinimide
- combo tx bc high density of organisms and slow growth promotoes resistance
mycobacterium leprae
- Hansen’s disease
- obligate intracellular, acid fast
- no in vitro culture
- cool temps –> skin and superficial nerves –> “glove and stocking” loss of sensation
- Lepromatous: poor CMI, diffuse skin involvement,leonine facies,paresthesia, lepromin (-)
- Tuberculoid: CMI contains disease but causes damage –> peripheral nerve damage, hypopigmented demarcated macules, lepromin (+ – can raise adequate immune response)
- Dx: acid fast bacilli in punch biopsy
- DOC: dapsone + rifampin + clofazimine
pseudomonas aeruginosa
- gram (-) rod, oxidase (+), aerobic bacillus (AER= AERobic and oxidase/O2)
- slime layer (encapsulated), grape odor
- water source, blue-green pigment (pyocanin)
- endotoxin –> fever and shock
- exotoxin –> inactivates eEF-2 (inhibits protein synthesis like diptheria)
- CF PTs: pneumonia
- burn PTs: pneumonia + cellulitis (blue-green pus) –> septicemia
- ecthyma gangrenosum (necrotic skin lesion – looks like black eschar) in septicemia
- malignant otitis externa in diabetics
- external otitis (swimmer’s ear – water connection)
- hot tub folliculitis (water connection)
- DOC: 4th gen PCN (piperacillin, ticarcillin) + aminoglycoside
- drug resistance: porin mutation that restricts many Abx from getting into cell
- PSEUDO: Pneumonia (CF), Sepsis, External otitis, UTI, Drug use and Diabetic osteomyeltitis
L. pneumophila
- gram (-) rod – stains poorly so use silver stain
- aerosol transmission from environmental water source (air conditioning, hot water tanks)
- grow on charcoal yeast extract with Cys and Fe
- Legionnaire’s disase: severe atypical pneumonia, fever GI and CNS symptoms (elderly smoker, heavy drinker or immunosuppressed)
- Pontiac fever: mild flu-like syndrome
- DOC: erythromycin
think of french legionnare (soldier) with his Silver helmet, sitting around a campfire (charcoal) with his Iron dagger – he is no sissy (cysteine)
Francesella tularensis
- gram (-) rod, aerobe, zoonosis, facultative intracellular pathogen (in reticulendoendothelial cells)
- reservoir: rabbits, deer, rodents
- transmission = tick bite, traumatic implantation, aerosols, ingestion of meat
- granulomatous rxn (manifestation of Type IV hypersensitivity response)
- Tularemia: AR, MO, TX
- diseases: ulceroglandular, glandular, oculoglandular, oropharyngeal and pneumonic
- DOC: streptomycin
Brucella sp
- gram (-) rod, aerobic, zoonosis, facultative intracell parasite (localizes in RES system)
- reservoir: domestic livestock
- transmission: unpasteurized dairy products, direct contact with animal (slaughterhouse)
- brucellosis: undulant fever (daily cycle), GI symptoms, osteoarthritis, GU problems (orchitis), hepatomegaly/splenomegaly
- DOC: doxycycline (intracellular parasite)
brUUUUcellosis = UUndUUUUlant
Bordetella pertussis
- gram (-) rod, aerobe, encapsulated
- filamentous hemagglutinin– mediates attachment to resp epi
- pertussis exotoxin overactivates adenylate cyclase (increased cAMP) –> localized edema, insulin secretion, lymphocytosis + alteration of immune effector cells
- whooping cough with post-tussis emesis
- DOC: erythromycin
- vaccine (DTaP)
campylobacter jejuni
- gram (-) curved/comma-shaped rod with polar flagella (“gulls’ wings”), facultative anaerobe, oxidase (+), microaerophilic, grows at 42 degrees C (likes the hot campfire)
- reservoir: undercooked poultry, or direct contact with infected animals (puppies)
- transmission: fecal-oral
- # 1 bacterial diarrhea in US
- invasive –> destroys mucosal surfaces –> inflammatory diarrhea (blood and pus in stool), fever and severe abdominal pain
- GBS and reactive arthritis
- DOC: FQ and erythromycin (if resistance)
helicobacter pylori
- gram (-) rod, curved, oxidase (+), microaerophilic (like campylobacter)
- urease (+) –> NH3 neutralizes stomach acid and allows bacterial growth
- chronic gastritis and duodenal ulcers
- type I carcinogen –> higher risk of gastric adenocarcinoma, gastric MALToma
- Dx: radiolabeled urea breath test
- Tx: omeprazole, amoxicillin, clarithromycin
Vibrio cholerae
- gram (-) **curved/comma-shaped **rod (C is curved), polar flagellae, oxidase (+)
- alkaline growth media TCBS (bile salts bc it’s ocean dwelling)
- transmission: fecal-oral (untreated water)
- cholera toxin (choleragen) increases fluid secretion –> persistent activation of adenylate cyclase –> increased cAMP –> increased Cl- secretion and H20 follows
- cholera: voluminous “rice water” stools –> severe dehydration
- Tx: Ringer’s solution to correct acidosis (via HCO3 loss in diarrhea), electrolytes, tetracycline for contacts (intracell and interstitial)
V. parahaemolyticus and V. vulnificans
- gram (-), oxidase (+), curved, motile rod
- salt-water borne (halophile)
- para: gastroenteritis (eating undercooked shellfish) –> NVD, cramps, fever
- para secretes enterotoxin simila to choleragen
- vulnificans: cellulitis (wounds exposed to seawater– hx of handling raw shellfish) –> rapidly fatal septicemia with hemorrhagic bullae
Enterobacteriaceae (family)
- gram (-) rods
- facultative anaerobes
- ferment glucose
- oxidase (-)
- **catalase (+) **
- reduce nitrates to nitrites
- lactose fermenters (Pink on Maconkey agar or black on EMB agar): E. coli and Klebsiella
- Non-lactose fermenters (colorless colonies): Shigella, Yersina, Proteus and Salmonella
E. coli
- gram (-) rods, enterobacteriaceae, ferments lactose (pink on MacConkey agar and black on EMB agar), facultative anaerobic, oxidase (-)
- reservoir: human colon (maybe vagina or urterhra); enterohemorrhagic strains (bovine feces)
- virulence factors: fimbrae and pilli – cystitis and pyelonephritis; K capsule – pneumonia and noenatal meningits; LPS endotoxin – septic shock
- all extracellular except EIEC
- diseases: UTI, neonatal septicemia/meningitis (materal fecal flora contaminate during birth), septicemia, gastroenteritis
EIEC
- Invasive E. coli
- bloody diarrhea
- fecal-oral transmission
- microbe invades intestinal mucosa –> necrosis and inflammation
- similar to Shigella (induces formation of actin jet trails bc it is also invasive)
ETEC
- enteroToxigenic E. coli, Traveler’s diarrhea (watery)
- produce enterToxins –> increased fluid secretion
- LT= heat-Labile toxin –> adenylate cyclase activation –> cAMP –> Cl- and H20 efflux
- ST- heat-Stable toxin –> guanylate cyclase activation –> cGMP –> decreased resorption of NaCl and H20 in gut
- CFAs (colonizing factor adhesins) prevent bacteria from not being flushed out with the diarrhea
- no inflammation or invasion
- tx: rehydration, TMP/SMX
EPEC
- E. coli; Pediatric diarrhea
- fecal-oral transmission
- no toxin produced
- adheres to apical surface, flattens villi –> prevents absorption
EHEC
- enteroHemorrhagic E. coli
- O157:H7 (most common serotype) – contains plasmid with Shigella Shiga toxin
- bloody diarrhea but not invasive –> therefore no inflamm response (fever, PMNs)
- kid eats undercooked hamburger
- verotoxin (Shiga-like): decrease protein synthesis by intefering with 60S ribosomal unit of euk endothelial cell –> HUS
- microthrombi form on damaged endothelial cells –> mechanical hemolysis (schistocytes) –> decreased RBF
- microthrombi consume plateletes –> thrombocytopenia
- Dx: nonfermenters of sorbitol (DDX from normal flora E. Coli)
- RX: antibiotics increase risk of HUS (further release of toxins)
Klebsiella pneumoniae
- gram (-) rod with large polysaccharide capsule, mucoid (thick gelatinous capsule = currant jelly sputum), ferments lactose
- reservoir: upper GI tract and colon
- **#2 cause lobar pneumonia (alcoholic – enteric flora is aspirated) **or PTs with chronic lung disease: currant jelly sputum
- UTIs: Nosocomial and catheterization
- # 2 cause gram (-) septicemia: immunocompromised or nosocomial
- DOC: 3rd gen cephalosporin +/- aminoglycoside
the major encapsulated organisms
- Some Killers Have Pretty Nice Capsules
- Strep pneumo
- Klebsiella
- H. influenza
- Pseudomonas
- Neisseria meningitidis
- Cryptococcus neoformans (yeast)
Shigella
- gram (-) rod, non-lactose fermenting Enterobacteriaceae
- fecal-oral transmission (daycare outbreaks of bloody diarrhea – as opposed to daycare outbreaks of non-bloody diarrhea with rotavirus)
- invasive: invade M cells and polymerize actin jet trails to travel intracellularly in gut
- **sshhigella sshhhoots like a jet
- Shiga toxin: neurotoxin, cytotoxin and enterotoxin – nicks 60S SU (inhibits protein synthesis –> enterocyte death)
- enterocolitis/shigellosis–> bloody diarrhea, fever and tenesmus
- risk of Reactive arthritis and HUS
- DOC: FQ and azithro (macrolide bc it’s intracellular)
invasive = blood and PMNs in stool + fever
Yersinia pestis
- gram (-) rod with bipolar staining, coagulase (+), facultative intracellular parasite
- zoonosis
- resevoir: US desert SW (wild rodents)
- vector: flea (flea bites infected animal then bites human)
- bubonic plague: fever, regional buboes, tender swollen LNs, conjunctivitis
- pneumonic plague: arises from septic PE in bubonic plague or inhalation of respiratory droplets from infected person (highly contagious!)
- Dx: “safety pin” staining
- Tx: aminoglycosides
Yersinia enterocolitica
- gram (-) rod, Enterobacteriacae, motile at 25 and non-motile at 37 degrees
- cold growth, prominent in northern climates
- reservoir: zoonotic
- transmission: unpasteurized milk, pork
- enterocolitis: inflammatory diarrhea or pseudoappendicitis
- mini-epidemics of pediatric diarrhea
- reactive arthritis
Proteus
- gram (-) rod, Enterobacteriaceae, urease (+), facultative anaerobe
- highly motile (“swarming”) –> allows it to swim up urethra and cause UTI
- biofilm –> UTI via catheter use
- fimbrae/pilli –> UTI
- reservoir: human colon and environment (normal flora gone bad)
- urease raises pH to cause kidney stones (staghorn renal calculi)
- diseases: UTIs and septicemia (rarely)
- DOC: aminoglycosides, bactrim
**think proteus = protein = kidney stones
Salmonella enterica subspecies typhi
- enterobacteriaceae, gram (-) rod, H2S (+), sensitive to acid
- reservoir: humans only (foodborne outbreaks)
- transmission: fecal-oral route from carriers (gallbladder)
- Typhoid Fever: invasive, reach BL side of M cells in gut–> transport in macrophages via lymphatics –> macro apoptosis, bowel perforation, bacteremia and toxemia (fever, HA, rose spots, constipation/diarrhea)
- only gastroenteritis with systemic manifestations
- osteomyelitis in sickle cell disease
- DOC: FQ or ceftriaxone (bc it’s intracellular)
Salmonella enterica (other than typhi)
- gram (-) rods, enterobacteriaceae, H2S (+)
- reservoir: enteric tracts of humans and chickens and turtles
- transmission: raw chicken/eggs, pet reptiles
- sensitive to stomach acid
- enterocolitis/gastroenteritis: inflammatory diarrhea, N+V, abdominal pain
- osteomyelitis in SCD
H. influenza
- encapsulated gram (-) rod, facultative anaerobe, requires X (Hemin) and V (NAD) for growth on nutrient/blood agar
- pleomorphic bacillus
- satellite phenomenon: grows near S. aureus on blood agar (Staph lyses the RBC for Haemophilus)
- reservoir: nasopharynx and conjunctiva
- polyribitol capsule, IgA protease
- pathogenic in kids: type B
- unvaccinated kids: meningitis, pneumonia, epiglottitis
- bronchitis + pneumonia in smokers with COPD
- secondary pneumonia (bronchopneumonia)
- DOC: Cefotaxime/ceftriaxone
- DX: antigen screen in CSF (latex particle agglutination to capsule)
- prevention: vaccination to type b
Gardnerella vaginalis
- gram (-) pleomorphic rod
- endogenous: normal flora get disturbed –> flourishes when vaginal pH increases, reduction of lactobacillus
- female PT with thin, vaginal discharge; post antibiotic or menses
- thin,grey, malodorous discharge (as opposed to frothy in trich)
- whiff test –> “fishy” odor when add KOH
- clue cells (epithelial cells covered with bacteria)
Pasteurella multocida
- gram (-) rod
- cat bite
- cellulitis + lymphadenitis within hours of bite (very rapidly spreading)
- Tx: augmentin (amox + clavulanate)
Bartonella henselae
- gram (-) rod
- cat scratch fever: exposure to kittens/cats –> fever, enlarged, tender LNs, papule/pustule at site on inoculation –> granulomatous rxn
- bacillary angiomatosis in AIDs: proliferation of BVs form tumor-like mass in skin (looks like Kaposi sarcoma)
Bacteriodes fragilis
- gram (-) rod, obligate anaerobe
- modified LPS, capsule
- predominant colonic flora
- predisposing factors: surgery, trauma, chronic disease (cancer)
- septicemia, peritonitis, abscess, aspiration pneumonia (R lower lobe abscess)
- foul-smelling (anaerobic)
- tx: metronidazole, clindamycin
- prevention: phrophylaxis for all GI and biliary tract surgery
obligate anaerobes
- Actinomyces israelli
- Bacteroides
- Clostridium
ABC’s
Borrelia burgdorferi
- spirochete, gram (-), difficult to culture
- Lyme disease
- reservoirs: white-footed mice, white-tailed deer
- vector: Ixodes ticks
- invades skin and spreads via bloodstream to involve primarly the heart, joints and CNS
- PT with influenza like symptoms and erythema migrans (target rash)
- spring/summer seasons
- later: neurologic (Bells Palsy), cardiac, arthritis/arthralgias
- tx: doxycycline (Jarish-Herxheimer rxn)
Leptospira interrogans
- spirochetes with tight terminal hooks
- zoonosis: reservoir = wild and domestic animals
- contact with animal urine in water –> penetrates mucous membranes or small breaks in epidermis
- jet skiiers, sewer workers, Hawaii
- influenza-like disease +/- GI symptoms
- Weil disease – severe form of disease with jaundice and azotemia from liver and kidney dysfunction; fever, hemorrhage and anemia
R. rickettsii
- obligate intracellular bacteria
- gram (-) envelope but stains poorly
- Reservoir: ticks, wild rodents
- vector: Dermacentor tick
- North Carolina
- Rocky Mtn Spotted Fever: HA, fever + rash on wrists/ankles –> trunk
- invade endothelial cells lining capillaries –> vasculitis in brain, liver, skin, lungs, kidney and GI tract
- PT with influenza-like symptoms and petechial rash that begins on ankles and wrists moves to trunk
- DOC: doxycycline (start w/o lab confirmation)
- Weil-Felix test
Ehrlichia
- obligate intracellular bacteria of mononuclear or granulocytic phagocytes
- same vector as Borrelia (Ixodes tick) –> coinfection
- PT with influenza-like symptoms,leukopenia, thrombocytopenia, no rash
- morulae inside monocytes or granulocytes (infects neutrophils)
mycoplasma pneumoniae
- lack cell peptidoglycan wall –> non-gram staining
- cholesterol required in membrane (but doesn’t not synthesize it)
- # 1 cause of aytpical/walking pneumonia (interstitial) - dorms or military recruits
- damage respiratory epi –> necrosis and bad, hacking cough
- cold aggluttinins (autoantibody to RBCs)
- no PCNs or cephalosporins (bc no peptidoglycan)
- DOC: erythromycin or tetracycline
Listeria monocytogenes
- gram (+) rod, beta-hemolytic (like strep!)
- facultative intracellular (can hide out in cells)
- acquired from unpasteurized dairy products of deli meats, via transplacentral transmission or by vaginal transmission at birth
- actin jet motility in cells – evades lysosomal degradation
- cold growth: soft cheeses, deli meats, hotdogs, coleslaw
- pregnant women: septicemia with fever and chills –> neonatal disease: granulomatosis infantiseptica (high mortality in utero)
- neonatal disease acquired through birth canal –> meningitis with septicemia (only gram + to produce LPS)
- meningitis in renal transplant and cancer PTs
- Rx: ampicillin with gentamycin
toxins that inhibit protein synthesis
- pseudomonas and diptheria: inactivate eEF-2
- shigella and EHEC: interfere with 60S ribosomal subunit
toxins that induce cAMP
- ETEC and V. cholera: profuse diarrhea
- B. anthracis: edema
- B. pertussis
catalase positive organisms
- Pseudomonas
- Listeria
- Aspergillus
- Candida
- E. coli
- S. aureus
- Serratia
you need PLACESS for your cats
**Chronic Granulomatous Disease are predisposed to these infections
urease positive organisms
- cryptococcus
- H. pylori
- Proteus
- Ureaplasma
- Nocardia
- Klebsiella
- S. epidermis
- S. saprophyticus
CHuck Norris hates PUNKSS
clostridium difficile
- gram (+) rod, spore-forming, obligate anaerobe
- toxin A = enterotoxin that binds to brush border of gut
- toxin B = cytotoxin that causes cytoskeletal disruption via actin depolymerization –> pseudomembranous colitis
- secondary to clindamycin or ampicillin
- tx metronidazole or oral vanco
oxidase (+), comma-shaped
- campylobacter (grows in 42 degrees C)
- vibrio cholerae (grows in alkaline medium)
- H. pylori (produces urease)
Rickettsia typhi
- endemic typhus
- transmission: fleas
- obligate intracellular
- rash starts centrally and spreads out, sparing palms and souls (opp of R. rickettsii)
- tx: doxy
Rickettsia prowazekii
- ePidemic typhus (P for prowazekii)
- human body louse
- obligate intracellular
- rash starts centrally and spreads out, spares palms and soles
- tx: doxy
Staphylococcus saprophyticus
- catalase (+), coagulase (-)
- Novobiocin R
- second most common cause of UTI in young women (#1 = E. coli)