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Flashcards in bacteria Deck (70)
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1
Q

N. meningitidis

A
  • 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
2
Q

N. gonorrhoeae

A
  • 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
3
Q

Treponema pallidum

A
  • 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
4
Q

S. aureus

A
  • 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)
5
Q

S. epidermis

A
  • 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
6
Q

strep pyogenes

A
  • 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
7
Q

strep agalactiae

A
  • 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
8
Q

streptococcus pneumoniae

A
  • 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
9
Q

strep viridians

A
  • 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)
10
Q

E. faecalis

A
  • 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)
11
Q

Bacillus anthracis

A
  • 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
12
Q

Bacillus cereus

A
  • 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
13
Q

Clostridium tetani

A
  • 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
14
Q

clostridium botulinum

A
  • 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
15
Q

Chlamydia trachomatis

A
  • 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”
16
Q

chlamydophila

A
  • C. pneumoniae: atypical pneumonia (sputum with intracytoplasmic inclusions)
  • C. psittaci: atypical pneumonia (exposure to parrots)
  • DOC: macrolides
17
Q

Clostridium perfringens

A
  • 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
18
Q

Corynebacterium diptheriae

A
  • 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
19
Q

Actinomyces israelii

A
  • 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
20
Q

trichomonas vaginalis

A
  • 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
21
Q

bacterial vaginosis

A
  • 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
22
Q

vaginal candidiasis

A
  • 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
23
Q

Nocardia asteroides

A
  • 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
24
Q

mycobacterium

A
  • acid fast rods
  • oblitage aerobes
  • waxy cell wall with high concentration of lipids (mycolic acids) that make them resistant to desiccation and many chemicals
25
Q

mycobacterium tuberculosis

A
  • 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
26
Q

mycobacterium leprae

A
  • 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
27
Q

pseudomonas aeruginosa

A
  • 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
28
Q

L. pneumophila

A
  • 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)

29
Q

Francesella tularensis

A
  • 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
30
Q

Brucella sp

A
  • 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

31
Q

Bordetella pertussis

A
  • 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)
32
Q

campylobacter jejuni

A
  • 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)
33
Q

helicobacter pylori

A
  • 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
34
Q

Vibrio cholerae

A
  • 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)
35
Q

V. parahaemolyticus and V. vulnificans

A
  • 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
36
Q

Enterobacteriaceae (family)

A
  • 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
37
Q

E. coli

A
  • 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
38
Q

EIEC

A
  • 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)
39
Q

ETEC

A
  • 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
40
Q

EPEC

A
  • E. coli; Pediatric diarrhea
  • fecal-oral transmission
  • no toxin produced
  • adheres to apical surface, flattens villi –> prevents absorption
41
Q

EHEC

A
  • 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)
42
Q

Klebsiella pneumoniae

A
  • 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
43
Q

the major encapsulated organisms

A
  • Some Killers Have Pretty Nice Capsules
  • Strep pneumo
  • Klebsiella
  • H. influenza
  • Pseudomonas
  • Neisseria meningitidis
  • Cryptococcus neoformans (yeast)
44
Q

Shigella

A
  • 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

45
Q

Yersinia pestis

A
  • 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
46
Q

Yersinia enterocolitica

A
  • 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
47
Q

Proteus

A
  • 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

48
Q

Salmonella enterica subspecies typhi

A
  • 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)
49
Q

Salmonella enterica (other than typhi)

A
  • 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
50
Q

H. influenza

A
  • 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
51
Q

Gardnerella vaginalis

A
  • 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)
52
Q

Pasteurella multocida

A
  • gram (-) rod
  • cat bite
  • cellulitis + lymphadenitis within hours of bite (very rapidly spreading)
  • Tx: augmentin (amox + clavulanate)
53
Q

Bartonella henselae

A
  • 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)
54
Q

Bacteriodes fragilis

A
  • 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
55
Q

obligate anaerobes

A
  • Actinomyces israelli
  • Bacteroides
  • Clostridium

ABC’s

56
Q

Borrelia burgdorferi

A
  • 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)
57
Q

Leptospira interrogans

A
  • 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
58
Q

R. rickettsii

A
  • 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
59
Q

Ehrlichia

A
  • 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)
60
Q

mycoplasma pneumoniae

A
  • 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
61
Q

Listeria monocytogenes

A
  • 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
62
Q

toxins that inhibit protein synthesis

A
  • pseudomonas and diptheria: inactivate eEF-2
  • shigella and EHEC: interfere with 60S ribosomal subunit
63
Q

toxins that induce cAMP

A
  • ETEC and V. cholera: profuse diarrhea
  • B. anthracis: edema
  • B. pertussis
64
Q

catalase positive organisms

A
  • Pseudomonas
  • Listeria
  • Aspergillus
  • Candida
  • E. coli
  • S. aureus
  • Serratia

you need PLACESS for your cats

**Chronic Granulomatous Disease are predisposed to these infections

65
Q

urease positive organisms

A
  • cryptococcus
  • H. pylori
  • Proteus
  • Ureaplasma
  • Nocardia
  • Klebsiella
  • S. epidermis
  • S. saprophyticus

CHuck Norris hates PUNKSS

66
Q

clostridium difficile

A
  • 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
67
Q

oxidase (+), comma-shaped

A
  • campylobacter (grows in 42 degrees C)
  • vibrio cholerae (grows in alkaline medium)
  • H. pylori (produces urease)
68
Q

Rickettsia typhi

A
  • endemic typhus
  • transmission: fleas
  • obligate intracellular
  • rash starts centrally and spreads out, sparing palms and souls (opp of R. rickettsii)
  • tx: doxy
69
Q

Rickettsia prowazekii

A
  • ePidemic typhus (P for prowazekii)
  • human body louse
  • obligate intracellular
  • rash starts centrally and spreads out, spares palms and soles
  • tx: doxy
70
Q

Staphylococcus saprophyticus

A
  • catalase (+), coagulase (-)
  • Novobiocin R
  • second most common cause of UTI in young women (#1 = E. coli)