MTAP: Remaining bacte

What does the presence of clue cells in a vaginal smear suggest

Bacterial vaginosis (BV).

• What are the two scoring systems used to diagnose BV

Amsel and Nugent scoring systems.

• Which bacteria is the agent of trench fever and is spread by human lice

Bartonella quintana.

• Which member of the HACEK group is mainly associated with endocarditis and appears as rosettes on a Gram stain

Cardiobacterium hominis.

• What disease results from a bite by a rat infected with Streptobacillus moniliformis

Rat-bite fever.

• What is the name of the disease caused by ingesting food contaminated with S. moniliformis

Haverhill fever.

• Which genus of bacteria is characterized as halophilic (except for two species) and inhabits marine water

Vibrio.

• What selective and differential medium is used to isolate Vibrio species

Thiosulfate-citrate-bile salt sucrose (TCBS) agar.

• What clinical sign is characteristic of a Vibrio cholerae O1 infection

"Rice-water" stool.

• Which Vibrio species is a highly virulent cause of septicemia after eating raw oysters

Vibrio vulnificus.

• What are the three clinically important complexes/biovars of Aeromonas

A. hydrophila complex

• Which bacterium is a major cause of food poisoning from undercooked poultry and shows "darting motility" on a wet mount

Campylobacter jejuni.

• What is the optimal incubation temperature for recovering C. jejuni from stool

42°C.

• Which bacterium causes peptic and duodenal ulcers and is linked to stomach cancer

Helicobacter pylori.

• Why do Mycobacteria resist traditional Gram staining

High concentration of mycolic acids in their cell wall.

• What is the primary stain used in an acid-fast stain (AFB)

Carbol fuchsin.

• Which mucolytic agent is used to liquefy mucus in respiratory specimens for Mycobacteria culture

N-acetyl-L-cysteine (NALC).

• What egg-based solid medium is used for growing Mycobacteria and contains malachite green

Lowenstein-Jensen (LJ).

• Which Runyon group describes slow-growing mycobacteria that produce pigment only when exposed to light

Group 1 (Photochromogens).

• Which biochemical test differentiates M. tuberculosis from most other species due to its unique accumulation

Niacin test.

What is the causative agent of Hansen disease (leprosy)

Mycobacterium leprae.

• Which mycobacterium is a common tap water contaminant and is rarely pathogenic

Mycobacterium gordonae.

• What indicator is used in anaerobic systems to confirm that oxygen has been removed

Methylene blue (turns from blue to white).

• Which anaerobic gram-negative bacillus is the major normal biota of the colon and responsible for most anaerobic infections

Bacteroides fragilis.

• Which anaerobic bacteria produce a brick-red fluorescence under UV light

Prevotella melaninogenica and Porphyromonas spp..

• What bacterium causes gas gangrene and produces a double zone of beta-hemolysis on blood agar

Clostridium perfringens.

• What neurotoxin produced by Clostridium tetani causes "lockjaw

" Tetanospasmin.

• Why should honey not be given to infants under 12 months of age

It can contain Clostridium botulinum spores which cause infant botulism.

• Which bacterium is the primary cause of antibiotic-associated pseudomembranous colitis

Clostridioides (Clostridium) difficile.

What are the four first-line drugs used to treat tuberculosis

Isoniazid rifampin ethambutol and pyrazinamide.

What is the primary method used to place bacteria into two major groups based on cell wall differences

Gram stain.

• Which rapid test identifies the fatty acid composition of the bacterial cell wall using gas chromatography

Sherlock Microbial Identification System (MIDI

• Which technology produces a unique protein spectral fingerprint for bacteria by vaporizing biomolecules with a laser

MALDI-TOF mass spectrometry.

• Which biochemical test is used to differentiate Vibrio species based on sucrose fermentation

TCBS (Thiosulfate-citrate-bile salt sucrose) agar.

• Which enzyme test is positive for most Vibrio species except V. metschnikovii

Oxidase.

• What rapid test is positive for Helicobacter pylori and can be demonstrated in stomach biopsy material

Urease.

• Which biochemical test is specifically used to differentiate M. tuberculosis (positive) from most other mycobacteria

Niacin accumulation.

• What test differentiates M. bovis (susceptible) from most other Mycobacterium species

T2H (thiophene-2-carboxylic acid hydrazide) susceptibility.

• What test uses a 1:1 mixture of 30% H{2}O{2} and 10% Tween 80 to differentiate members of the M. tuberculosis complex

Heat-sensitive catalase (68^{\circ}C).

• Which anaerobic test identifies the production of proteolytic enzymes that produce an opaque zone or a "mother-of-pearl" sheen on agar

Egg yolk agar (Lecithinase and Lipase tests).

• Which indicator turns from blue to white to confirm anaerobic conditions have been met in a GasPak jar

Methylene blue.

• What test identifies Clostridium perfringens by observing an enhanced zone of hemolysis when grown with Group B streptococci

Reverse CAMP test.

• What is the causative agent of Lyme disease

the most common tickborne disease in the U.S.

• What is the unique clinical hallmark of the early stage of Lyme disease

Erythema migrans (a "bull's eye" rash).

• Which spirochete causes epidemic relapsing fever and is transmitted by human body lice

Borrelia recurrentis.

• What is the most accurate method for detecting antibodies to B. burgdorferi following a positive screen

Western immunoblotting.

• Which spirochete causes leptospirosis (Weil's disease) and is acquired through contact with animal urine

Leptospira interrogans.

• What are the specialized media used to recover Leptospira from blood or urine

Fletcher’s or Ellinghausen-McCullough-Johnson-Harris (EMJH).

• What is the lowest concentration of an antimicrobial agent that visibly inhibits the growth of an organism

Minimal Inhibitory Concentration (MIC).

• What class of antibiotics includes penicillins and cephalosporins and inhibits cell wall synthesis

Beta-lactams.

• How do bacteria commonly exhibit resistance to beta-lactam antibiotics

By producing beta-lactamase (an enzyme that cleaves the beta-lactam ring).

• Which class of drugs is active against both Mycoplasma and Chlamydia

Tetracyclines.

• What serious side effect limits the use of Chloramphenicol to only life-threatening infections

Aplastic anemia (bone marrow suppression).

• What is the only glycopeptide approved for use in the U.S. to treat resistant gram-positive infections

Vancomycin.

• Which phenotypes have been isolated due to resistance to vancomycin

VRE (Vancomycin-resistant enterococci) and VRSA (Vancomycin-resistant S. aureus).

• In the context of MRSA (Methicillin-resistant Staphylococcus aureus)

what defines MDR-TB

• What term describes the combined effect of two antimicrobials being greater than the sum of their individual effects

Synergy.

What is the standard thickness and pH required for Mueller-Hinton agar (MHA) in a Kirby-Bauer disk diffusion test

4 mm thick at a pH of 7.2–7.4.

What is the purpose of the D-zone test

To detect inducible clindamycin resistance by erythromycin.

• What anticoagulant is used in blood culture bottles to inhibit complement and inactivate neutrophils

Sodium polyanethol sulfonate (SPS).

Using the cefoxitin disk diffusion method

what zone size indicates that S. aureus is oxacillin resistant

• In a broth dilution test

what MIC value for oxacillin defines S. aureus as resistant

Why do gram-positive bacteria appear blue/purple

They have a thick layer of peptidoglycan that retains the primary stain

• What is the characteristic result of a catalase test for Gardnerella vaginalis

Catalase negative.

• Which bacteria are typically oxidase positive

Vibrio species (except V. metschnikovii) Aeromonas Campylobacter and Helicobacter pylori.

What does the Gram stain detect in the cell wall to differentiate bacteria

Peptidoglycan concentration.

• What enzyme does the Catalase test detect by adding hydrogen peroxide to a culture

Catalase.

• Which biochemical test identifies the presence of cytochrome c oxidase in the electron transport chain

Oxidase test.

• What does the Indole test detect as a metabolic byproduct of the amino acid tryptophan

Indole.

• Which test determines the ability of an organism to produce the enzyme tryptophanase

Indole test.

• What does the Methyl Red (MR) test detect in the IMViC series

Stable acid end products from glucose fermentation.

• What does the Voges-Proskauer (VP) test detect to identify neutral end products like acetoin

2

• What does the Citrate test detect regarding bacterial metabolism

The ability of an organism to use citrate as its sole carbon source.

• What does the PYR test detect to identify Group A Streptococci and Enterococci

L-pyrrolidonyl arylamidase enzyme.

• Which test detects the ability of an organism to liquefy gelatin by producing proteolytic enzymes

Gelatin hydrolysis test.

• What does the Coagulase test detect in Staphylococcus aureus

The enzyme coagulase which converts fibrinogen to fibrin.

• What does the Bile Solubility test detect in Streptococcus pneumoniae

Amidase enzyme activity that lyses the cell wall in the presence of bile salts.

• What does the Hippurate Hydrolysis test detect to identify Group B Streptococci

The enzyme hippuricase which breaks down sodium hippurate to glycine and benzoic acid.

• What does the ONPG test detect in slow lactose fermenters

Beta-galactosidase enzyme.

• What does a Triple Sugar Iron (TSI) agar slant detect

Glucose lactose and sucrose fermentation as well as H2S and gas production.

What does the Urease test detect by observing a color change to bright pink

The hydrolysis of urea into ammonia and CO2.

• Which test detects the enzyme that removes an amino group from phenylalanine

Phenylalanine deaminase (PAD) test.

• What does the Nitrate Reductase test detect in the identification of Mycobacteria and Enterobacteriaceae

The reduction of nitrate to nitrite or nitrogen gas.

• What does the Heat-sensitive Catalase test at 68°C detect in Mycobacteria

The presence of a heat-stable version of the catalase enzyme.

• What does the Arylsulfatase test detect in the identification of M. xenopi

The enzyme that breaks down phenolphthalein disulfate.