Micro - Clinical Bacteriology Flashcards
staph aureus identification
gram positive catalase positive (clusters) coagulase positive beta hemolytic (clear)
staph aureus VF
protein A - binds to Fc portion of IgG to prevent complement fixation + phagocytosis
staph aureus diseases
inflammatory - skin infection, organ abscesses (coagulase - fibrin clot), pneumonia
toxin-mediated - TSS (TSST-1), scalded skin syndrome (exfoliative toxin), rapid onset food poisoning (enterotoxins)
acute bacterial endocarditis and osteomyelitis
MRSA
methicillin-resistant staph aureus
nosocomial and community acquired infection
resistant to b-lactams (altered PBP)
toxic shock syndrome
staph aureus
TSST-1 - MHC + TCR –> IL2 + IFNy –> fever, shock, rash, desquamation, end organ failure due to polyclonal T cell activation
cause of staph aureus food poisoning
ingestion of preformed toxin (enterotoxin)
staph epidermidis labs
gram positive cocci catalase positive (clusters) coagulase negative
NESSIR - NOVOBIOCIN SENSITIVE
staph epidermidis
produces adherent BIOFILM –> prosthetic devices + IV catheters
normal skin flora
contaminates blood cultures
strep pneumo labs
lancet shaped, gram positive DIPLOcocci catalase negative (chains), alpha hemolytic (green), OVERPASS - OPTOCHIN SENSITIVE, positive quellung - capsule
strep pneumno diseases
MOPS - meningitis, otitis media (kids), pneumonia, sinusitis
strep pneumo associations
3 S’s –> rusty sputum, sepsis in sickle cell anemia and splenectomy
strep pneumo virulence
CAPSULE
IgA protease - cleaves IgA to invade resp mucosa
viridans group strep labs
gram positive catalase negative (chains), alpha hemolytic (green), overpass - optochin resistant
strep mutans and strep sanguis
normal flora of the oropharynx
strep mutans
dental caries
strep sanguis
glycocalx –> subacute bacterial endocarditis at damaged valves
strep pyogenes diseases
pyogenic - pharyngitis, cellulitis, impetigo
toxigenic - scarlet fever, toxic shock like syndrome, necrotizing fasculitis
immunologic - RF + (impetigo->)acute glomerulonephritis
strep pyogenes VF
M protein - inhibits phagocytosis
antibodies vs m protein can lead to RF
Rheumatic fever
JONES - polyarthritis, carditis, subcutaneous nodules, erythema marginatum, sydenhams chorea
how to detect recent strep pyogenes infection
ASO titer
scarlet fever
strep pyogenes - strawberry tongue, scarlet face sparing face, scarlet throat
strep agalactiae
colonizes vagina; BABIES - meningitis, pneuomnia, sepsis
screen preggers 35-37 weeks, psoitive = intrapartum prophylaxis with penicillin
produces CAMP factor
strep agalactiae - enlarges area of hemolysis formed by staph aureus
hippurate test positive
strep agalactiae
enterococcus
E. faecalis + E. faecium - normal colonic flora
penicillin G resistant –> UTI, biliary tract infections + subacute endocarditis
VRE - nosocomial infection
can grow in bile salts and 6.5% Nacl
Enterococci
streptococcus bovis
gut; bacteremia and subacute endocarditis in COLON CANCER PATIENTS
bovus in blood = cancer in colon
cystine-tellurite agar
corynebacterium diphtheria - black colonies
lab diagnosis for corynebacterium diptheria
gram positive CLUB-SHAPED rod, metachromatic (blue and red) granules and elek’s test for toxin
this prevents diphtheria
toxoid vaccine
Cornybacterium diphtheria
ABCDEFG - adp ribosylation, beta prophage, cornebacterium diptheria, elongation factor 2, granules
spores
highly resistant to heat and chemicals
DIPICLONILIC ACID
how to kill spores
autoclave by steaming at 121 degrees celcius for 15 minutes
spore producing bacteria
gram positive bac in soil = bacillus anthracis, clostridum perfringes, C. tetani
others = B. cereus, C. botulinum, coxiella burnetti
clostridium labs
gram positive rods, obligate anaerobes, spore-forming
clostridium tetani
tetanospasmin - exotoxin protease cleaving SNARE –> prevents release of GABA/glycine from RENSHAW cells in s/c *spastic paralysis, lock jaw (trismus), risus sardonic us
clostridium botulinum causes
adults - ingest preformed toxin
babies - ingest spores in honey
clostridium botulinum
preformed heat-labile toxin - inhibits ach release –> flaccid paralysis
floppy baby syndrome
clostridium botulinum
clostridium perfringes
alpha toxin - myonecrosis (gas gangrene) and hemolysis
clostridium difficle
toxin A - enterotoxin binds brush border of gut –> diarrhea
toxin B - cytotoxin destroys cytoskeletal strucutre of enterocytes –> pseudomembranous colitis
often secondary to antibiotic use
clostridium difficile - clindamycin or ampicillin (diagnose = toxin in stool)
clostridium difficile treatment
metronidazole or oral vancomycin
only bacterium with polypeptide capsule (D-glutamate)
bacillus anthracis
cutaneous anthrax
contact - black eschar (painless ulcer) –> possibly bacteremia and death
lethal factor + edema factor –> black skin lesions = black eschar (necrosis) surrounded by edematous ring
pulmonary anthrax
inhale spores –> flu-like sx –> rapid to fever, pulm hemorrhage, mediastinitis, shock
woolsorters disease
inhalation of bacillus anthracis spores (pulmonary anthrax) from contaminated wool
reheated rice syndrome
bacillus cereus
bacillus cereus
food poisoning - spores survive cooking rice
emetic - rice/paste; N&V in 1-5 hours due to cereulide (preformed toxin)
diarrheal type - water, nonbloody diarrhea + GI pain 8-18 hours
tumbling motility
listeria monocytogenes
this is how you get listeria monocytogenes
ingest unpasteurized milk/cheese + deli meats or vaginal transmission in birth
form actin rockets - move cell to cell
listeria monocytogenes
actinomyces
normal oral flora - oral/facial abscesses that drain through sinus tracts
nocardia
found in soil - pulmonar y infections in immunocompromised + cutaneous infections after trauma in immunocomptent
form yellow sulfur granule
actinomyces
treatment of actinomyces
penicillin
treatment of nocardia
sulfonamides
extrapulonary TB in vertebral body
potts disease
TB sx
fever, night sweats, weight loss, hemoptysis
leprosy
hansens disease
glove and stocking loss of sensation, ARMADILLOS
lepromatous - diffusy over skin + communicable - low CMI w/ humoral TH2 response (can be lethal)
tuberculoid - few hypoesthetic hairless skin plaques, high CMI w/ large TH1 response
leprosy tx tuberculoid form
dapsone + rifampin for 6 months
leprosy tx lepromatous form
dapsone, rifampin + clofazimine for 2-5 years
neisseria
gram negative diplococci
ferment GLUCOSE
IgA protease
neisseria gonorrhea
sexually transmitted –> gonorrhea (within polymorphonuclear leukocytes), septic arthritis, neonatal conjunctivitis, PID
neisseria meningitis
ferments maltose, polysach capsule, vaccine (none for type B, resp + oral secretions –> meningococcemia + meningitis
causes fitz-hugh curtis syndrome
neisseria gonorrhea
causes waterhouse-friderischsen syndrome
neisseria meningitis
neiserria meningitis prophylaxis in close contact
rifampin, ciprofloxacin, or ceftriaxone
treatment of neisseria gonococci
ceftriaxone and (azithryomycin or doxy) for possible chlamydia coinfection
treatment of neisseria meningitis
ceftriaxone or penicillin G
h flu vaccine
type B capsular polysaccharide conjugated to diphtheria toxoid or other protein. 2-18 months
haemophilus influenze
EMOP - epiglottis (cherry red in kids), meningitis, otitis media, pneumonia
most invasive = capsular type B
nontypable strains - mucosal infectinos (otitis media, conjunctivitis, bronchitis)
IgA protease
h flu transmission
aerosol
tx h flu meningitis
ceftriaxone
tx h flu prophylaxis in close contact
rifampin
legionarres disease
severe pneumonia, fever, GI + CNS sx
pontiac fever
legionella pneumophila
mild flu-like syndrome
grows on charcoal yeast extracted with cystine and iron
legionella pneumophila
legionella pneumophila dx, transmission, tx
dx - antigen in urine (labs - hyponatremia)
transmission - enrivonmental water source habitat
tx - macrolide or quinolone
pseudomonas aeruginosa
PSEUDO - pnuemonia (CF), sepsis (black lesions on skin), external otitis (swimmers ear), UTI, drug use, diabetic osteomyelitis
associated with wound and burn infections
pseudomonas aeruginosa
produces pyocyanin (blue-green pigment)
pseudomonas aeruginosa
grape-like odor
psueodmonas aeruginosa
pseudomonas aeruginosa
endotoxin (fever, shock) + exotoxin A (inactivates EF-2)
AERuginosa - AERobic, water source + blue-green pigment, burn victims
chronic pnuemonia in CF patients = biofilm
tx pseudomonas aeruginosa
aminoglycoside + extended-spectrum penicillin (piperacillin, ticarcillin)
E coli VF
fimbrae - cystitis + pyelonephritis
K capsule - pneumonia, neonatal meningitis
LPS endotoxin - septic shock
EIEC
INVADES intestinal mucosa –> necrosis + inflammation (dysentery)
ETEC
HLT + HST
watery TRAVELERS diarrhea
EPEC
PEDIATRIC diarrhea in kids
adheres to apical surface –> flattens vili + prevents absorption
EHEC
shiga-like toxin + HUS –> necrosis + inflammation (dysentry)
O157:H7
does not ferment sorbitol
endothelium swells + narrows lumen - mechanical hemolysis + reduced renal blood flow, damaged endothelium consumes platelets
hemolytic uremic syndrome triad
anemia, thrombocytopenia, acute renal failure
red currant jelly sputum
klebsiella - abundant polysaccaride capsule –> mucoid colonies
lobar pnuemonia in alcoholics + diabetics that aspirated
klebsiella
klebsiella
nosocomial infection
4 A’s –> alcoholics, abscesses in lungs/liver, diAbetics, aspiration pneumonia
salmonella
flagella, disseminate hematogenously, animal reservoirs, produce hydrogen sulfide, invades intestinal mucosa –> monocytic response
shigella
cell-cell transmission, human/primate reservoirs, invade intestinal mucosa –> PMN infiltration, BLOODY DIARRHEA
salmonella typhi
typhoid fever, humans
rose spots on the abdomen, fever, headache + diarrhea***
carrier state - gallbladder
campylobacter jejuni
bloody diarrhea in kids
fecal oral tranmission - pountry, meat, unpast milk
–> GBS + reactive arthritis
vibrio cholerae
rice-water diarrhea - cholera toxin (Gs-cAMP)
endemic to developing countries
req prompt oral rehydration
rice water diarrhea
vibrio cholera
yersinia enterocolitica
pet feces (puppies), contaminated milk or pork mesenteric adentitis - mimics crohns/appendicitis
h pylori
gastritis + 90% duodenal ulcers
RF - peptic ulcer, gastric adenocarcinoma + lymphoma
urease positive
h pylori initial tx
PPI, clarithromycin and amoxicillin or metronidazole
wrights stain
borrelia
leptospira interoggans
water contaminated with animal urine –> leptospirosis = flu-like sx, jaundice, photophobia w/ conjunctivitis
prevalent among surfers and in tropics (hawaii)
leptospira interrogans
weils disease
leptospira interrogans - jaundice and azotemia from liver and kidney dysfunction; fever, hemorrhage, anemia
borrelia burdorferi
LYME DISEASE
transmission - tick Ixodes with mouse reservoir
northeastern US
lyme disease tx
doxycycline, ceftriaxone
Lyme disease
stage 1 - erythema chronicum migrans (bulls eye rash w/ central clearing), flu-like sx
stage 2 - neuro (facial nerve palsy) + cardiac (AV nodal block) manifestations
stage 3 - MSK (monoarthritis + migratory polyarthritis), neuro (encephalopathy + polyneuropathy) + cutaneous manifestation
FAKE - facial n palsy (BL), arthritis, kardiac block, erythema migrans
treponema pallidum
syphilis; visualized with dark field microscopy
syphilis tx
penicillin G
primary syphillis
localized w/ painless chancre - treponemes
screen = VDRL –> confirm = FTA-ABS
secondary syphilis
Systemic - maculopapular rash (palms/soles), condylomata lata - treponemes
screen = FDRL –> confirm = FTA-ABS
tertiary syphilis
gummas (chronic granulomas), aortitis (vaso vasorum destruction), neurosyph (tabes dorsalis), argyll robertson pupil
sign = broad-based ataxia, positive romberg, charcot joints, stroke w/o HTN
test spinal fluid w/ VDRL
congenital syphilis
saber shins, saddle nose, CN VIII deafness, hutchinsons teeth, mulberry molars
early prevention!!! placental transmission after 1st trimester
argyll robertson pupill
constracts with accomodations but is NOT reactive to light ***tertiary syphillis
prostitutes pupil = accomodates but does not react
VDRL false positives
VDRL - viral infections (mono, hep), drugs, RF, SLE + Leprosy
jarisch-herxheimer rxn
flu-like syndrome immediately after antibiotics started
due to killed bacteria releasing pyrogens
cat scratch disease
bartonella
lyme disease
borrelia burdorferi - ixodes ticks (deer/mice)
recurrent fever
borrelia recurrentis - louse (variable surface antigens)
undulant fever
brucella - unpasteurized diary
campylobacter
bloody diarrhea - puppies/livestock (fecial oral, ingest undercooked meat)
chlamydophila psittaci
parrots
q fever
coxiella burnetti - aerosols of cattle/sheep amniotic fever
lone star tick
ehrlichia chaffeensis
francisella tularensis
tickets, rabbits, deer fly
leptospira
animal urine
armadillos
mycobacterium leprae
pasteurella multocida
cellulitis/osteomyelitis - animal bit, cats + dogs
rickettsia prowazekki
epidemic typhys - louse
rash stats centrally and spreads out - sparing palms/soles
TYPHUS - TRUNK
rickettsia rickettsie
RMSF - dermacentor tick bite
rickettsia typhi
endemic typhus - fleas
yersinia pestis
plague - fleas (rats/prarie dog = reservoirs)
gray vaginal discharge with FISHY smell
gardnerella vaginalis - I dont have a clue why i smell fish in the vagina garden!
clue cells
gardnerella vaginalis
gardnerella vaginalis tx
metronidazole
rickettsia tx
doxycycline
rocky mountain spotted fever
rash at wrist/ankles –> spreads mediately to trunk/palms/soles
rickettsia = obligate intracell requiring CoA and NAD+
WRICKETTSIA - WRISTS
triad - headache, fever, rash (vasculitis)
palms and soles rash
CARS - cox A, rocky mountain spotted fever, secondary syphilis
monocytes with morula in cytoplasm
ehrlichiosis (ticK)
granulocytes with morula in cytoplasm
anaplasmosis (tick)
MORULA GAME - gran ana, mono erchlic
Q fever
coxiella burnetti
tick feces + cattle placenta release spores -> inhaled as aerosols -> pneumonia
queer - no rash no vector and causative organism can survive outside in endospore form
chlamydiae
elementary body - enters via endocytosis
reticulate body - replicates by fission *seen on tissue culture
chlamydia trachomatosis
reactive arthritis, conjunctivitis, nongonococcal urethritis + PID
chlamydia tx
azithromycin (one-time) or doxycycline
chlamydia pnuemoniae + pstitaci
atypical pneumonia
aerosol transmisison
chlamydia lab dx
cytoplasmic inclusions on Giemsa or fluorescent antibody-stained smear
cell wall lacks muramic acid
chlamydia
chlamydia trachomatis subtypes
ABC - chronic infection - blindness due to follicular conjunctivitis in africa (AFRICA, BLIND, CHRONIC)
D-K - everything else (urethritis/PID, ectopic preggers, neonatal penumonia (staccato cough) or neonatal conjunctivitis) *neonatal - passage through infected birth canal
L1,L2,L3 - lymphogranuloma venereum
atypical walking pneumonia
mycoplasma pneumonia, < 30 year old, freq outbreak in military recruits/prisons
sx - insidious onset, headache, nonproductive cough, diffuse interstitial infiltrate. Xray worse than prognosi
mycoplasma pneumonia
high titer cold agglutinins (IgM)
grown on eatons agar
mycoplasma pneuomnia
mycoplasma pneuomnia tx
macrolide or fluoroquinolones (no cell wall = penicillins ineffective)
cell wall contains sterols for stability
mycoplasma pnuemonia