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Bacteria II
Laboratory tests
42
Microbiology
Graduate
09/30/2009
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Term
Bordetella
 Definition
o clinical presentation
During paroxysmal phase: leukocytosis (>50000 cells/μL, normal is 4500-11000); nasopharyngeal swab: gram stain may be difficult because low number of organisms; culture: bordet-genou media (within 3 – 7 days; serological: direct fluorescent antibody test, antibodies against the toxins
Term
NG
 Definition
 Males: numerous PMNs containing organism
 Females: + GC culture
 If bacteremiaculture skin, joint fluid, blood
 oxidase+
 ferments glucose but not maltose
 aerobic growth with enhancement with 5% CO2
 chocolate agar
 Thayer-Martin medium
 Rapid NAATs (nucleic acid amplification tests)
Term
NM
 Definition
 encapsulated in CSF and blood
 transparent, non-pigmented non-heme on chocolate with 5% CO2
 Thayer-Martin agar
 oxidase+
 fermentation of glucose and maltose
Term
Escherichia
 Definition
 G- rods, oxidase-, cat+
 Lactose fermenters: pink on MacConkeys
 EHEC: does not ferment sorbitol (detected on MacConkeys sorbitol agar)
 Antigenic structure: O, K, H (O157:H7)
Term
Salmonella
 Definition
 Isolation of bacteria from blood, feces, urine, left over foods
• Bile salts inhibit Gram + and most other Enterobacteriaceae
• Salmonella-Shigella media: Thiosulfate and citrate used to indicate H2S production during glucose fermentation: colonies with black centers
Term
Shigella
 Definition
 isolation from feces on Salmonella-Shigella media
Term
Y. pestis
 Definition
• clinical presentation
• gram stain; growth on MacConkey agar
Term
Y. enterolotica and pseudotuberculosis
 Definition
• obtained from stool sample
• isolation on MacConkey at 4 C
• Serological testing: anti-Yersinia antibodies
Term
Vibrio
 Definition
 Rice water – V. cholera O1 or O139
 Gram stain of stool difficult
 Direct fluorescent antibody test of stoll
 Media:
• alkaline peptone broth
o survive and replicate at high pH
o selective
• Thiosulfate citate bile salts sucrose (TCBS) agar
o selective/differential
 V. cholera grow yellow
 Biochemical and serological tests
Term
Aeromonas
 Definition
 oxidase +
 beta hemolysis
Term
Campylobacter
 Definition
 gull-wing appearance in gram stain
 darting motility (characteristic)
 culture on special media with antibiotics that inhibit normal flora
 Catalase, oxidase, and hippurase +
Term
Helicobacter
 Definition
 gastric biopsy
 urease, catalase, and oxidase+
 serum antibodies
 Urease breath test: patient ingests radioactive labeled urea: if microbe is present, urea will be split into ammonia and CO2radioactive –labeled CO2 detected upon exhalation
Term
Pseudomonas
 Definition
o non-selective media
 creamy colonies on MacConkeys agar: does not ferment lactose
o beta hemolysis
o oxidase and catalase +
o pigment production: blue or yellow-green
o fruity odor: characteristic
Term
Haemophilus
 Definition
o gram stain: pleomorphic, gram – coccobacilli
o X and V factors on chocolate agar
o type b capsule detection
o nucleic acid analysis
Term
o F. tularensis
 Definition
 slow growth (2-10 days) on chocolate or buffered charcoal yeast extract (BCYE), both supplemented with cysteine
 agglutination with specific antibodies
 antibody titer
Term
o B. melitensis
 Definition
 slow growth (3 days to weeks) on blood agar
 oxidase, catalase, and urease +
 antibody detection
Term
Leginonella
 Definition
o 2-5 days on BCYE, not blod or chocolate: must have cysteine and iron, amino acids (does not use carbs), charcoal absorbs toxic fatty acids, pH (6.9)
o direct fluorescence antibody test
Term
Bartonella quintana
 Definition
Culture of special media with patient antibodies
Term
o C. perfringens
 Definition
 clinical presentation
 absence of WBCs and G+ rods
 rapid (<1 day) growth on blood agar with double zone of hemolysis: theta (inner zone of beta hemolysis) and alpha (outer zone of alpha hemolysis)
 nagler reaction: hydrolysis of phospholipids in egg yolk agar
 detection of high number of bacteria in food or feces
 detection of enterotoxin
Term
o C. difficile
 Definition
 clinical symptoms and toxins in feces
Term
o C. tetani
 Definition
 clinical presentation
 difficult to culture: small number of organisms, killed by O2
 difficult to detect toxin or antibodies in patient: toxin is internalized by neurons
Term
o C. botulinum
 Definition
 clinical presentation
 Food borne: toxin detected in food or patient serum, feces or gastric fluid
 Infant: toxin detected in feces or serum
 Wound: toxin detected in serum or wound
Term
Actinomyces israeli
 Definition
o clinical symptoms, history of trauma, slowly progressive course
o lab diagnosis can be difficult: part of normal flora, slow growers, anaerobic
o presence of sulfur granules: gram stain
o culture: takes 1-2 weeks to see growth under anaerobic conditions: distinctive colony morphology
Term
Spirochete general
 Definition
 difficult to grow
 difficult to visualize with light microscopy because do not stain well and/or very thing
• darkfield, immunofluorescence or special stains
Term
T. pallidum
 Definition
 do not grow in cell-free cultures: not routinely cultured in lab
 requires immunofluorescent or dark-field microscopy
 nontrepenomal screening tests
• detects nonspecific antibody, reagin, that reacts with cardiolipin (phospholipid found in beef heart tissue): inexpensive
• flocculation tests: consist of adding cardiolipin to patient’s serum
o positive: cardiolipin forms into fine aggregates/floccules
o other diseases may give positive reactions
o all positive sera must be retested to confirm with specific treponemal tests
 treponemal tests
• FTA-ABS (fluorescent treponemal antibody – absorbed): freeze-dried organism fixed to slide
o patient serum is added
o slide is rinsed, covered with fluorescent-labeled abs against human Ig
o positive=spirochete-fluorescent ab complex fluoresces
• Particle agglutination test
o antigens on gelatin particles are mixed with patient serum: specific abs will cause particles to agglutinate
Term
B. burgdorferi
 Definition
 early disease: clinical presentation, especially rash (no antibodies yet)
 late disease : patient antibodies (false positives)
Term
B. recurrentis
 Definition
 clinical presentation
 appearance of Giemsa-stainable, loosely coiled spirochetes in blood during febrile stage
Term
o L. interrogans
 Definition
 sensitive to drying and many disinfectants
 survival in slightly alkaline water for weeks
 difficult to visualize
 slow growth on specialized media: 2 weeks to 4 monts
 serological agglutination test
Term
Mycoplasma pneumoniae
 Definition
Staining: poor or not at all
• Absence of organisms may be suggestive
– Sputum analysis: scanty and nonpurulent
• Cultured on special agar, 1-6 weeks
– High antibody titer
Term
M. hominis
 Definition
requires arginine, fried egg colonies
Term
M. genitalium
 Definition
difficult to culture at all
Term
U. urealyticum
 Definition
requires urea and buffered media
Term
R. rickettsii
 Definition
clinical grounds; Giemsa or Gimenez stain; serology: indirect fluorescent antibody test for patient antibodies against OmpA; Direct fluorescent antibody test; PCR based tests
Term
R. akari
 Definition
indirect immunofluorescence antibody test
Term
R. prowazekii
 Definition
Serology: Epidemic typhus (IgM followed by IgG antibodies); Brill-Zinsser (IgG anamnestic response)
Term
R. typhi
 Definition
Serology: indirect fluorescent antibody test
Term
Ehrlichia and Anaplasma
 Definition
Leukopenia, thrombocytopenia, elevated serum tranaminases; microscopic observation of morulae in blood smears (rare for HME, possible for HGA); culture rare; serology common; DNA probes available
Term
Coxiella burnetti
 Definition
Serology: acute (antibody to phase II); chronic (antibody to phase I and II)
Term
C. trachomatis
 Definition
Culture: staining inclusions, specific but not sensitive; antigen detection (ELISA or IF): group specific LPS, stain specific outer membrane proteins; serology: cannot distinguish between current or past infection, detection of high titer IgM antibodies can be helpful; NAATs
Term
Chlamydophila psittaci
 Definition
fourfold rise in titer
Term
Chlamydophila pneumoniae
 Definition
fourfold rise in titer
Term
B. henselae
 Definition
pt. antibodies
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