MMG 463 Exam 3 – Flashcards
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| Staphylococcus Saprophyticus SBA with Furazolidone and Novobiocin |
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| -Susceptible to furazolidone (large inhibition zone around FX) -Saprophyticus is one of several Strep species resistant to Novobiocin (C-) -Appears gamma hemolytic |
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| Staphylococcus Saprophyticus Infection types, populations affected |
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| UTI's in young women |
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| Staphylococcus Saprophyticus API Staph ID Panel, pt. 1/2 (red=neg, yellow=pos) |
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| CHO-/MNE-/TRE+/MEL-/GLU+/MAL+/MAN+/FRU+/LAC+/XLT- |
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| Staphylococcus Saprophyticus API Staph ID Panel, pt. 2/2 |
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| VP+/SAC+/ADH-/NIT-/RAF-/MDG-/URE+/PAL+/XYL-/NAG- |
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| S. Saprophyticus -How to uniquely ID with API |
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| -API biocode shows possible S. Sapro, S. Warneri, or S. Homonis -Saprophyticus is the only of that group that is resistant to Novobiocin |
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| Non-Pathogenic Lactobacilli (Vaginal Microbiota) Gram Stain Morphology |
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| Gram positive bacilli in single, pair, or short chain |
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| Vaginal Microbiota SBA Colony Morphology |
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| Small, round, brownish with bright yellow center, appears alpha-hemolytic |
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| Vaginal Microbiota Gram stained smear of vaginal specimen |
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| Specimen has large endothelial cells Gram Positive ones are normal (lactobacilli) |
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| Gardnerella Vaginalis Type of infection? |
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| Bacterial vaginosis |
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| G. Vaginalis Gram stained vaginal smear |
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| Gram negative bacilli and coccobacilli associated with large endothelial cells |
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| G. Vaginalis on CNA blood agar? |
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| NOTE: caprophytic (req. 5-7% CO2) Colonies are very small, best observed in areas of confluent growth |
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| G. Vaginalis on HBT? |
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| NOTE: HBT= Human Blood Bilayer-Tween medium Gardnerella req. 35-37C and 5-7% CO2 Small, B-Hemolytic colonies |
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| G. Vaginalis any other media? |
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| Rapid carb-utilization (technique used for Neisseria identification) Produces acid from GLUC/MALT not from Mannitol Highly hippurate hydrolysis + (black) |
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| T. Pallidum Incubation period |
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| 50% of infex's contact can escape infection, as few as 57 orgs needed to infect Lasts from 3-90 days, mean=3 weeks |
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| T. Pallidum Primary Syphilis |
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| Lesion (chancre; not always present)=Clean/smooth base, firm raised edge Usually painless, slightly tender Scant exudate unless 2* infexn in chancre, heals in 3-6 wks Multiple chancres can occur in immunodeficient Enlarged regional LN's Confirmatory Lab test for 1* is darkfield microscopy w/ spirochete presence, as Nontreponemal tests are false (-) in 10-30% of syphilis cases |
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| T. Pallidum Secondary Syphilis |
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| Organisms are most numerous 2-8 weeks after chancre's appearance Most dramatic: widespread rash (feet/hands=maculopapular or pustular), non-vesicular Moist areas: gray-white plaque (condylomata lata) high in spirochete# Darkfield microscopy or immunofluorescence Systemic: lymphadenopathy, fever, malaise, any organ could be involved (hepatitis, keratitis, osteitis) CNS infexn happens in this phase= Meningismus and headache, also aseptic meningitis can happen No clear line b/t 1* and 2*, as 1* chancre can be present when rash develops |
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| T. Pallidum Latent Syphilis |
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| Follows 2*, org is subclinical (not dormant) Early latent= 4 year pd, relapses occur and patient is infex's during them 90% relapses in first year Disease presence can be serologically determined in this phase. |
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| T. Pallidum Late syphilis |
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| Complications: CNS disease, CV abnorm's, tumors (gummas- occur in any organ) |
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| T. Pallidum Test for late neurosyphilis |
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| VDRL assay of CSF that shows elevated proteins and decreased glucose --org is utilizing your brain's fuel |
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| T. Pallidum Types of syphilis/characteristics |
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| CV: 10% of untreated cases, inflamm of aorta (syphilitic aortitis). Aortic aneurism/dilation of aortic ring= not enough blood through aortic valve Late "benign" syphilis: 15% of untreated, gummas= most common complication, can destroy surrounding tissue as it enlarges. VDRL's insensitivity means must use FTA-ABS (fluorescent treponemal AB absorption) Congenital: many fetuses die. Survivors have lesions of 2* syph b/c no 1* entry site. Abnorm's of bone and teeth. Penicillin therapy for mother, baby's VDRL should be norm after 6 months and FTA-ABS w/in a year. |
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| Serologic tests of Syphilis 2 types, tests filed under each type, and characteristics |
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| Non-Treponemal: includes VDRL and RPR. Tests for an antibody to cardiolipin (tissue lipid). FLAW: In late syphilis, these appear very low or negative. Also, affected by antitreponemal therapy Treponemal: Uses specific treponemal antigens. Still very high in late, unlike non-treponemal. Incl FTA-ABS, TPHA, and TPI. FTA-ABS is very specific, but can produce false pos in treponeme other than syphilis; detects IgM or IgG. FTA-ABS is the cheapest of the 3, and replaced TPI |
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| Serologic tests of Syphilis Provisional and Investigative Tests |
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| Enzyme/particle agglutination immunoassays becoming more frequently used. Also: Western Blot has 92% sens in symptomatic infants, and 83% in asymptomatic (looking for 47 kD specific ag). Immunoblots are used as confirmatory tests |
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| Mobiluncus Etiology: Condition, People affected |
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| Bacterial Vaginosis (member in nonspecific vaginitis) Women |
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| Mobiluncus Bacterial Characteristics (Gram, Aer/An, Appearance, spores) |
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| Variable Gram Negative stain (GP wall char's), Gull-wing Rod in singles or pairs, motile, non-spore forming Anaerobe Lacking of outer membrane (typical of G+), yet young cultures stain gram variable; older stain gram neg |
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| Bacterial strains associated with bacterial vaginosis |
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| Gardnerella vaginalis Mycoplasma hominus Mobiluncus Spp Peptostreptococcus anaerobius, P. asaccharolyticus, P. magnus |
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| Typical characteristics of bacteria associated with bacterial vaginosis |
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| Anaerobic cocci Anaerobic Gram pos rods (eg. Propionibacterium) =Synergistic infection |
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| Diagnostic criteria of bacterial vaginosis |
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| 1. thin but profuse discharge 2. pH>4.5 3. fishy odor (esp. upon adding 10% KOH) 4. Clue Cells: squamous epithelial cells w/ many small rods adherent to surface (wet mount/Gram) |
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| Mobiluncus cultures |
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| Grow on many non-selective media (ABA, CHOC) 2-4 days, colonies are 2-4 mm in diameter, colorless, smooth, flat, sometimes spreading appearance |
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| How to differentiate Mobiluncus from M. curtisii and M. mulieris |
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| NEG) Indole and Catalase POS) Growth in Arg presence, Hippurate hydrolysis -->(Difficult to differentiate) |
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| Chlamydia Trachomatis Direct detection in clinical specimens: methods? |
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| Right-Giemsa (or Gimenez) Inclusions in cytoplasm of epithelial cells are perinuclear, must distinguish from fragmented nuclei. |
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| Chlamydia Trachomatis Frequency of inclusion detection for each kind of specimen |
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| Inclusions detected... MOST in neotatal conjunctivitis Less in adult conjunctivitis/trachoma LEAST in urethritis and cervicitis |
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| Chlamydia Trachomatis Antigen detection technique/plate appearance in a positive result |
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| Uses immunofluorescence/enzyme immunoassay Evans blue-->Cells stain bright red, black background Antigens fluoresce yellow/bright green McCoy cell monolayer treated with cyclohexamide, fluorescein-conjugated monoclonal antibody. All black, sparse tiny green dots=intracytoplasmic inclusion |
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| Chlamydia Trachomatis Nucleic Acid detection tests, names, sensitivity |
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| 1st: Gen-Probe, DNA probe agains rRNA (sens~80-95% dep. on population) 2nd: Amplification of any kind~ more sens. than hybridization (like Gen-Probe) MOST COMMON NA TESTS: PCR, Strand Displacement Amplification, Transcription-Mediated Amplification |
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| Chlamydia Trachomatis problem with NA detection (amplification) |
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| Cost--all are more sensitive than cheaper methods, and can detect in urine, but used less |
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| Chlamydia Trachomatis When are screens performed? Interpretation? |
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| Screening is typically done in asymptomatic phase, Inconclusive tests are up to the lab director |
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| Neisseria gonorrhoeae Gram stain taken from male with these symptoms (2); appearance |
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| Gonococcal urethritis, and subsequent discharge Intracellular diplococci within pale neutrophils |
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| Neisseria gonorrhoeae Growth requirements, typical medium (describe) |
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| 35-37 C @ 5% CO2 MTM (modified Thayer-Martin) Agar. =Chocolate-agar contains vancomycin (GP), colistin (GN), and nystatin (Fungal) *parentheses=orgs inhibited by each |
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| Neisseria gonorrhoeae Colony characteristics |
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| on MTM (looks like a more red CHOC) Colonies are somewhat large, yellowish brown, glossy |
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| Neisseria gonorrhoeae CTA--> What is it? What does N. gonorrhoeae look like? |
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| Cysteine Tryptic Agar Semisolid agar to ID Neisseria Spp.; differentiates by sugars utilized; CTA-(Glucose, Maltose, Sucrose, Lactose, Control) N. Gono-->ONLY UTILIZES GLUCOSE (phenol red indicator turns yellow) |
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| Neisseria gonorrhoeae GONOCHEK II test principles, result appearance/interpretation |
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| 3 chromogenic substrates to detect glycosidase and aminopeptidase activity in Neisseria (Meningitidis, lactamica, gonorrhoeae) BLUE->Lactamica (B-galactoside hydrolysis) YELLOW->Meningitidis (gamma-glutamyl-p-nitroanilide hydrolysis) PINK/RED->Gonorrhoeae (prolyl-B-naphthylamide hydrolysis) COLORLESS-> presump. Moraxella Catarrhalis |
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| Haemophilus ducreyi Disease? Characteristics of this disease? |
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| Chancroid, may resemble syphilis chancres, but are painful and soft (syphilis=painless/hardened), can culture the bacteria from these lesions |
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| Bacillus anthracis Gram stain/Malachite Green spore stain |
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| relatively large Gram positive bacilli with terminal endospores that don't swell the cell. Spore stain: ovoid spores (no swelling), bamboo arrangement (also in Gram) |
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| Signs/Symptoms of GI Anthrax? |
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| Lesions of cecum and adjacent areas of bowel cause abdominal pain, bloody diarrhea and hematemesis (blood vomit) |
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| Bacillus anthracis on SBA? |
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| Offwhite, dull, nonhemolytic, comma-shaped outgrowths ("Medusa-head Colonies") |
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| Bacillus sereus on SBA |
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| (more frequently isolated bacillus in lab); unlike B. anthracis, is B-hemolytic, motile, and B-lactamase positive |
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| Yersinia pestis Presentation on humans |
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| Hematogenous spread can cause IV coagulation-->endotoxic shoc-->small hemorrhages on skin |
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| Yersinia pestis Gram stain |
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| short, plump gram-neg rods bipolar stain shows pale center, characteristic "safety-pin" appearance |
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| Yersinia pestis Wright stain-- done on what kind of sample? |
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| Peripheral blood smear; shows dark blue bacteria, light blue PMNs with purple nuclei, and tan RBCs |
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| Yersinia pestis On SBA- time to culture, colony morphology |
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| 48-72 hours grey-white to slight yellow (looks blue in book), opaque, raised, irregular "fried-egg" shape. May have "hammered copper" shiny surface. gamma-hemolytic |
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| Listeria monocytogenes Gram stain morphology |
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| short, gram positive bacilli (in picture, kinda looks like clumped cocci) |
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| Listeria monocytogenes SBA (growth requirements, hemolytic patterns) |
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| 72 hours @ 35-37 C and 5% CO2 B-hemolytic, but not very visible after first 24 hours. Even after 48 hours, hemolysis barely extends from colony margin, and is not much more evident than the 48 hour sample |
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| Listeria monocytogenes Bile-esculin agar characteristics, appearance, and interpretation |
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| When not inoculated, medium is golden brown Like enterococci, Listeria monocytogenes hydrolyzes esculin in the presence of 40% bile Medium turns black |
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| Francisella tularensis Disease? Characteristics? |
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| Tularemia; Inguinal lymphadenopathy, abdominal distension, watery diarrhea Similar to typhoid Meningitis-associated (low gluc/high protein near brain) |
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| F. tularensis Biosafety levelIsolation obtained from? |
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| BSL-3, prior it was 2 (bioterror threat) Take from primary ulcer, LN aspirate or biopsy, sputum, BM, and tissue biopsy. Cultures isolated from typhoidal, pneumonic, oropharyngeal |
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| F. tularensis Growth method? |
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| BACTEC- takes 7-9 days to grow MTM agar/CHOC: enriched with IsoVitalex Buffered Charcoal Yeast Extract (BCYE) Agar: -->Used for legionella; can support fastidious org's Requires 5% CO2 (caprophilic), 2-5 days at 35-37 C. |
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| F. tularensis ID method vs other Francisella? |
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| PCR, 16s rRNA sequencing, DNA probe hybridization, EIA using monoclonal LPS subsp. tularensis. |
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| F. tularensis Serologic tests |
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| Hard to diagnose til late in the course, so serologic tests are BEST FOR DIAGNOSIS. (tube agglutination, TA) |
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| Rickettsia Infected organs Transmission route |
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| Symptomatic= Skin, Lung, Brain obligate intracellular pathogen Tx: Arthropod Bite Cats/opossums |
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| Coxiella burnetii Transmission/infection type |
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| obligate intracellular pathogen infected milk or aerosols |
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| Scrub typhus: t/f endemic in USA |
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| False-- Orientia tsutsugamushi (Cent/East Asia?) seen w/ 1* eschar- seen rarely with Rocky Mtn Spotted Fever |
