Term
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Definition
Catalase(hydrogen peroxide) positive, but coagulase negative. Non hemolytic.
Normal flora of skin and mucous membranes
Attaches to nylon/plastic easily (IV, shunts, etc.)
Prevention: change catheter, use stainless steel, Not plastic |
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Term
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Definition
gold colonies, beta hemolytic, coagulase positive, Reservoir = carriers (nose/skin), direct contact transmission
Virulence factors = structural (coagulase, protein A, capsule); toxin (enterotoxin, exfoliatin, leukocidin, toxic shock syndrome toxin, DNAse)
Diseases = Skin infections, food poisoning, endocarditis following bacteremia, osteomyelitis, pneumonia, TSS, scalded skin syndrome
Treatment = drain abscesses, antibiotis (oxacillin, methicillin, vancomycin); no vaccines, use public health measures |
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Term
| staphylococcus saprophyticus |
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Definition
| Catalase positive, but coagulase negative; non-hemolytic; can cause UTIs in women (honeymoon cystitis) |
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Term
| Group A Streptococci (pyogenes) |
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Definition
Gram-positive cocci, growing as chains. Beta hemolytic. bacitracin sensitive
Virulence factors = Structural (Pili, Capsule), toxins (streptokinase (tissue), steptodornase (DNA), hyaluronidase (CT), Pyrogenic toxin, Erythrogenic toxin
Reservoir = carriers (throat/skin)
Diseases = sore throat w/ complications (tonsillitis, peritonsillar abscess, ludwig's angina, mastoiditis, middle ear infections, meningitis, scarlet fever)
Skin infections (impetigo w/ S. aureus)
Secondary infection of skin lesions (acne, trauma, burns)
Spread to lymphatics (cellulitis, puerperal fever, necrotizing fasciitis)
Post-streptococcal conditions:
-Acute glomerulonephritis
-Rheumatic fever
Transmission = direct contact
Prevention = no vaccines, prophylactic antibiotics
Treatment = topical bacitracin, Penicillin G, erythromcin |
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Term
| Group B Streptococci (agalactiae) |
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Definition
Beta hemolytic, bacitracin resistant
Reservoir = can be part of normal female GU flora
Transmission = to baby, at birth
Diseases = neonatal sepsis and meningitis
Prevention = preg women screened and given antibiotics w/ labor |
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Term
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Definition
alpha hemolytic diplococci, No lancefield group, sensitive to bile/optochin
Reservoir = throat
Toxins = polysaccharide capsule (virulence factor/antigen)
Diseases: pneumonia or bronchitis in persons w/ compromised lung drainage; bacteremia can result in meningitis or endocarditis
Vaccine = polysaccharide capsule
Treatment = caphalosporin, used to be penicillin |
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Term
| Enterococcus fecalis (streptococcus fecalis, Group D) |
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Definition
Non-hemolytic, bile resistant, bile/optochin resistant
Reservoir = colon (normal flora)
Diseases = abnormal abscess, UTI, endocarditis
Treatment = penicillin G resistant, therefore combo of penicillin and aminoglycosides used |
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Term
| Viridans Streptococci (Streptococcus viridans) |
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Definition
No lancefield group; alpha hemolytic, bile/optochin resistant
Reservoir = normal flora of the mouth and female GU
Virulence factors = extracellular polysaccharides, Acids
Diseases = dental caries, endocarditis (bacteremia w/ prior rheumatic fever or prior surgery), infected prosethetic joints |
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Term
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Definition
Non-hemolytic, no lancefield group, obligate anaerobes, bile/optochin resistant
Reservoir = normal flora of mouth, resp. tract, female GU, and bowel
Diseases = abscesses (often complex mixture of organisms) |
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Term
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Definition
| - Gram (-) rod, non-lactose fermenting, Non-H2S producing, non motile, facultative anaerobes, intracellular (parasitic) |
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Term
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Definition
fecal-oral gastroenteritis, very low infectious dose, bateremia very rare
-virulence factors (shiga toxin, plasmid borne)
-risk of complications (Reiters syndrome or reactive arthitis, HUS) |
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Term
| Shigella (diagnosis /treatment) |
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Definition
Physical exam (fever, dehydration, severe headache, progression from watery to bloody diarrhea)
Lab = aggulination, methylene blue stain of fecal matter
HUS = blood smear
Treatment = rehydrate antibiotics if needed (ceftriaxone, fluroquinolone, azithromycin, or cefixime), hygiene (water treatment, hand washing) |
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Term
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Definition
| -Gram(-) rod, facultative anaerobe, lactose fermenter, indole positive, H2S negative, may be mobile or non-mobile, normal GI flora |
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Term
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Definition
-Gastroenteritis (watery diarrhea, bacteria attach to gut lining, enterotoxins force cells to release fluids, potassium)
-Bloody gasteroenteritis (bloody diarrhea, bacteria invade gut lining, O157:H7 E. Coli carry shigella plasmid, risk of HUS)
-UTIs (most common cause of uncomplicated, host usually carries strain in normal GI flora, have P fimbriae virulence factor, risk of bacteremia, particularly w/ urinary obstruction)
-Meningitis (neonates, cranial trauma/surgery, high morbidity)
-Pneumonia (rare, follows untreated UTI, GI infection) |
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Term
| E. Coli (Diagnosis / Treatment) |
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Definition
Physical exam
Culture = blood agar and differential medium
HUS = blood smear
EIA test = tests colonies for shga toxin
Treatment = Gastroenteritis (rehydrate), Bloody gastroenteritis (no antibiotics = HUS, rehydrate), UTI, meninigitis (ampicillin + cefotaxime)
Prevention = handwashing, cranberry juice (UTI), remove IV/catheter (nosocomial) |
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Term
| Salmonella (bacteriology) |
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Definition
| Gram (-) rod, motile, seldom lactose fermenting, oxidase (-), urease (-), H2S (+) |
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Term
| Salmonella (pathogenesis) |
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Definition
-Enterocolitis (usually typhimurium, enteritidis, heidelberg; bacteria invade gut wall, immune containment, bacteremia = rare)
-Enteric Fever (Typhoid; typhi or paratyphi, high infectious dose, invasion of gut wall leads to transport in macrophages, spreads via lymphatics to major organs = macrophage apoptosis, bacteremia, toxemia)
-Septecemia (invade vulnerable tissue, may progress to osteomyelitis, pneumonia, meningitis; metastatic abscess form in previously damaged tissue) |
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Term
| Salmonella (Diagnosis/Treatment) |
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Definition
-Diagnosis = Enterocolitis (non-bloody diarrhea, fever, dehydration; culture from stool), Enteric fever (high fever, headache, tender abdomen, anorexia, lethargy, rose spots sometimes; culture from stool, blood, and BM), Septecemia (focal symptoms at affected organ)
-Treatment= Enterocolitis (rehydrate, antibiotics), Enteric fever (vaccines available, antibiotics: ceftriaxone or ciprofloxacin), Septecemia (drain abscess, ceftriaxone or ciprofloxacin)
Prevention = notify authorities of possible foodborne outbreak, handwashing/food prep |
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Term
Y. enterocolitica and pseudotuberculosis
(bacteriology) |
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Definition
| -Gram (-) oval rods, non lactose fermenting, urease (+), motile at 25C, nonmotile at 37C |
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Term
Y. enterocolitica and pseudotuberculosis
(pathogenesis) |
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Definition
-Y. enterocolitica = entercolitis, virulence factors on Ch and plasmid, high infectious dose, false appendicitis when spreads to local lymph nodes, bacteria lack siderophores, infection enhanced by iron overload, most common in young children, bacteria rare/deadly), and infection predisposes to Reiters Syndrome
-Y. pseudotuberculosis = rarer infection, seen w/ immunocompromise or liver disease, pediatric infection may cause Izumi Fever |
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Term
Y. enterocolitica and pseudotuberculosis
(Diagnosis / Treatment) |
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Definition
-Diagnosis = diarrhea, dehydration, false appendicitis, culture from blood, CSF, cold-enrich and plate on CIN, mAb tests available
-Treatment = normal entercolitis, mesenteric adenitis (replace fluid/electrolytes), bacteremia, abscess, severe enterocolitis (trimethoprim-sulfamethoxazole or cipro)
-prevention = food prep and handwashing |
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Term
Klebsiella/Enterobacter/Serratia
(bacteriology) |
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Definition
-Gram (-) rods, K are nonmotile/encapsulated, H2S(-), K&E are lactose fermenters, All indole (-)
-Normal flora (usually opportunistic), highest risk of infection in men, neonates, elderly
-major problems w/ antibiotic resistance |
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Term
Klebsiella/Enterobacter/Serratia
(pathogenesis) |
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Definition
-K. pneumonia (usually predisposed by advanced age, chronic resp. disease, diabetes, alcoholism; nosocomial outbreaks; polysaccharide capsule defends against phagocytosis, complement, adhesins bind gut, siderophores chelate iron; most lethal = "currant jelly sputum" seen from lobar pneumonia, less lethal =bronchitis, UTI, wound infection, catheter infection)
-Enterobacter (nosocomial ICU bugs, opportunistic, mortality and presentation depend on underlying disease)
-S. marcenscens (opportunistic nosocomial, adult patients = bloodstream, lower resp, GU, surgical wounds, skin, soft tissue, peds = meingitis, wound infection, arthritis, heroin addicts = endocarditis, osteomyelitis) |
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Term
Klebsiella/Enterobacter/Serratia
(Diagnosis / Treatment) |
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Definition
-Diagnosis = nosocomial infection, Ab resistance testing, gram stain culture (K. pneumonia = mucoid, S. marcenscens = red-pigmented colonies)
-Treatment = antibiotic (based on sensitivity test), can begin w/ aminoglycoside/cephalosporin for K,S; choice of Ab for E = more complicated
-Prevention = remove catheter/device |
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Term
Proteus/Providencia/Morganella
(bacteriology) |
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Definition
| -Gram (-) rods, non-lactose fermenting, produce phenylalanine deaminase and urease, some proteus "swarm" or produce H2S, normal flora, usually opportunistic nosocomial, problematic antibiotic resistance |
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Term
Proteus/Providencia/Morganella
(pathogenesis) |
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Definition
-Primarily UTIs (fimbriae attach to urinary tract, mobile bacteria go up, urease production raises bladder pH and leads to stones, obstruction = bacteremia)
-Proteus can also cause pneumonia or wound infection
-Providencia may cause gastroenteritis, rarely ocular infections, endocartitis
-Morganella (rarest) causes wound infections, can also cause sepsis and pneumonia |
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Term
Proteus/Providencia/Morganella
(Diagnosis/Treatment) |
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Definition
-Diagnosis = UTI, flank pain, history of recent beta-lactam Ab therapy; Lab (gram stain/culture, enzyme immunoassay)
-Treatment = remove infected catheters, drain abscess, antibiotics (test sensitivity, start w/ aminoglycosides or trimethoprim/sulfamethoxazole, for indole (+) = cephalosporin) |
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Term
Rickettsia
(bacteriology) |
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Definition
| -Very short rods, hard to Gram stain (-), all use arthropod vectors, obligate intracellular parasites |
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Term
Rickettsia [Spotted Fevers]
(pathogenesis) |
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Definition
-Rocky Mountain Spotted Fever = vectored by ticks, bacteremia, invade & multiply in vascular endothelium, blood vessels leak as infected cells die, rash
-Mediterranean Spotted Fever = vectored by dog ticks, not common in US, eschar forms at site of tick bite |
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Term
Rickettsia [Spotted Fevers]
(Diagnosis / Treatment) |
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Definition
-Diagnosis = RMSF (headache, fever, myalgia, vasculitis rash, history of tick bite, delirium, coma, DIC), Mediterranean (eschar, less severe than RMSF)
-immunochemical tests available
-Treatment = doxycycline (if neither preg or allergic), alternate = chloramphenicol, prevention = protective clothing, insect repellent |
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Term
Rickettsia [Typhus]
(pathogenesis) |
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Definition
-Epidemic Typhus (cold-weather) = unique b/c humans are host/reservoir, vectored by lice, multiply in vascular endothelium, untreated 2 wks = mortality from vascular collapse/pneumonia)
-Brill-Zinsser Disease- less severe than initial course, risk factors are malnutrition or inadequate antibiotics during first typhus
-Murine Typhus (warm) = accidental transmission to humans of cat/rat typhus, seen in S and SW US; milder than epidemic typhus
-Scrub Typhus (warm) = accidental transmission to humans of O. tsutsugamushi, vectored by chigger, milder than epidemic typhus, eschar may form at bite site |
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Term
Rickettsia [Typhus]
(Diagnoisis / Treatment) |
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Definition
-Diagnosis = epidemic typhus (abrupt fever, chills, headache, lymphadenopathy, CNS symptoms, history of flea bite, natural disaster/war, cold weather), Brill Zinsser (similar, milder, history of epidemic typhus), Murine and scrub typhus (similar, milder, more common in warm weather, cough, lymph node involvement w/ scrub)
-Lab (confirm w/ IF assay, immunoassay, PCR
-Treatment = begin antibiotics before labs come back, doxycycline or chloramphenicol, azithromycin/rifampicin effective against doxycycline resistant Thai strain
-Prevention = epidemic (hygiene, delousing, vaccine), murine/scrub (protective clothing, repellant) |
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Term
Coxiella Burnetii: Q fever
(bacteriology) |
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Definition
| proteobacteria (related to legionella), zoonosis of asymptomatic infection of ruminants, transmitted by inhalation of aerosols of infected urine, feces, birthing matter (unique = no vector!) |
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Term
Coxiella Burnetii: Q fever
(pathogenesis) |
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Definition
| Common in Netherlands, France, Spain, Iraq; extremely infectious, multiplies in aveolar monocytes/macrophages, rides to liver, spleen, bone marrow, creates complications of pregnancy |
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Term
Coxiella Burnetii: Q fever
(Diagnosis / Treatment) |
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Definition
-Diagnosis = pneumonia, fever, chills, sweats, severe headaches, dry cough, hepatitis; Lab (IF, IHC, ELISA)
-Treatment = doxycycline or fluoroquinolones, prevention = vaccine |
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Term
Ehrlichia: Human monocytic ehrlichiosis
(bacteriology) |
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Definition
| -Tiny gram (-) rod, obligate intracellular parasite, replicate in cytoplasm in WBCs, form clusters called morulae, vectored by ticks among reservoirs and accidentally to humans |
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Term
Ehrlichia: Human monocytic ehrlichiosis
(pathogenesis) |
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Definition
| Often asymptomatic, but can proceed to thromobocytopenia and DIC, may co-infect with another pathogen by same vector |
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Term
Ehrlichia: Human monocytic ehrlichiosis
(Diagnosis / Treatment) |
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Definition
-Diagnosis = severe headaches, myalgias, fever, shaking chills history of travel to endemic areas, lab (CBC, elevated serum transaminase, morulae on blood smear), PCR or immunostain confirmation
-Treatment = doxycycline, fluoroquinolones, prevention (protective clothing, repellant) |
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Term
Anaplasma: Human granulocytic anaplasmosis
(bacteriology) |
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Definition
| -small gram (-), obligate intracellular, survive and multiply in early endosome of WBCs, grow into morulae, vectored by ticks |
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Term
Anaplasma: Human granulocytic anaplasmosis
(pathogenesis) |
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Definition
| Often asymptomatic, but can proceed to thrombocytopenia + DIC, may co-infect w/ another pathogen by same vector |
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Term
Anaplasma: Human granulocytic anaplasmosis
(Diagnosis / Treatment) |
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Definition
-Diagnosis = fever, headache, myalgia, no rash, history of hiking and traveling in endemic areas, Lab (leukopenia, thrombocytopenia, mild liver injury, confirm by PCR or immunostaining)
-Treatment = few require Intensive care, doxycycline, alternate fluoroquinolones, prevention = protective clothing, insect repellant |
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