Micro Exam 3
Which organism is sometimes mistaken for Salmonella and will agglutinate in Salmonella polyvalent antiserum? C. freundii strains Proteus mirabilis strains S. sonnei strain E. coli
C. freundii strains
A fastidious gram-negative bacillus was isolated from a case of periodontal disease, which upon darkfield examination was noted to have gliding motility. The most likely identification of this etiologic agent would be Capnocytophaga Chromobacterium Kingella Plesiomonas
Capnocytophaga
Rapid testing for beta-lactamase production is recommended, before initiation of antimicrobial therapy, for isolates of Serratia marcescens Haemophilus influenzae Staphylococcus epidermidis Streptococcus pyogenes
Haemophilus influenzae
In multi-drug resistant tuberculosis (MDR-TB), which drugs normally used in first-line treatment of TB are ineffective? Amikacin and kanamycin Aminoglycosides Fluoroquinolones Isoniazid and rifampin
Isoniazid and rifampin
Which of the following Legionella spp. is positive for Hippurate hydrolysis? L. micdadei L. longbeachae L. gormanii L. pneumophila
L. pneumophila
Which drug known to be active against parasitic infections has importance as a therapeutic agent in cases of disease caused by anaerobic bacteria? Isoniazid Metronidazole Rifampin Trimethoprim
Metronidazole
Which atmospheric condition is needed to recover Campylobacter spp. from specimens inoculated onto a Campy-selective agar at 35°C-37°C and 42°C? 5% O2, 10% CO2, and 85% N2 20% O2, 10% CO2, and 70% N2 20% O2, 20% CO2, and 60% N2 20% O2, 5% CO2, and 75% N2
5% O2, 10% CO2, and 85% N2
The pH of the agar used for the Kirby-Bauer test should be 7.0-7.2 7.2-7.4 7.4-7.6 7.6-7.8
7.2-7.4
The colonies shown in this 5% sheep blood agar (left) and MacConkey agar (right) split frame photograph are most likely those of: Escherichia coli Enterobacter sakasakii Proteus mirabilis Morganella morganii
Morganella morganii
A gram-negative rod is recovered from a catheterized urine sample from a nursing home patient. The lactose-negative isolate tested positive for indole, urease, ornithine decarboxylase, and phenylalanine deaminase and negative for H2S. The most probable identification is: Edwardsiella spp Morganella spp Ewingella spp Shigella spp
Morganella spp
Which genera are positive for phenylalanine deaminase? Enterobacter, Escherichia, and Salmonella Morganella, Providencia, and Proteus Klebsiella and Enterobacter Proteus, Escherichia, and Shigella
Morganella, Providencia, and Proteus
Which group of tests best identifies the Morganella and Proteus genera? Motility, urease, and phenylalanine deaminase Malonate, glucose fermentation, and deoxyribonuclease (DNase) Indole, oxidase, MR, and VP Indole, citrate, and urease
Motility, urease, and phenylalanine deaminase
The agar recommended by the Clinical and Laboratory Standard Institue for routine susceptibility testing of nonfastidious bacteria is MacConkey agar Middlebrook 7H10 agar Mueller-Hinton agar Trypticase soy agar
Mueller-Hinton agar
Which of the following media should be used for in vitro susceptibility testing of S. pnuemoniae? Chocolate agar Charcoal yeast extract agar Mueller-Hinton base supplemented with 5% lysed horse blood Mueller-Hinton base supplemented with 1% hemoglobin and 1% IsoVitaleX
Mueller-Hinton base supplemented with 5% lysed horse blood
Which of the following antimicrobial agents acts by inhibiting protein synthesis? Gentamicin Methicillin Rifampin Ampicillin
Gentamicin
The phenomenon of bacterial resistance to the bactericidal activity of penicillins and cephalosporins, with only inhibitions of organism's growth, is known as High-level resistance Intrinsic resistance Inducible resistance Tolerance
Tolerance
The following statement is true regarding hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) and community-associated MRSA (CA-MRSA)? Resistance is conferred by the mecA gene for only the HA strains. CA strains tend to demonstrate resistance to more drug classes than HA strains. CA strains tend to be associated with the PVL gene and skin and soft tissue infections. Incorrect: HA Strains are typically more susceptible to non-beta-lactam antibiotics.
CA strains tend to be associated with the PVL gene and skin and soft tissue infections.
A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-negative bacillus and the physician would like to use an antibiotic that inhibits cell wall synthesis. Which of the following antibiotics would be the best choice? Gentamycin Tetracycline Ciprofloxacin Cefazolin
Cefazolin
The extended-spectrum beta-lactamases confer resistance to Amoxicillin Ceftriaxone Erythromycin Rifampin
Ceftriaxone
The most sensitive method for the detection of β-lactamase in bacteria is by the use of: Chromogenic cephalosporin Penicillin Oxidase Chloramphenicol acetyltransferase
Chromogenic cephalosporin
Which of the following organisms is often confused with the Salmonella species biochemically and on plated media? E. coli Citrobacter freundii Enterobacter cloacae Shigella dysenteriae
Citrobacter freundii
Which of the following amino acids are required for growth of Francisella tularensis? Leucine and ornithine Arginine and lysine Cysteine and cystine Histidine and tryptophan
Cysteine and cystine
Which of the following is not true about Pasteurella multocida? Most common human infections occur in soft tissues, bones, and joints Humans harbor the organism as part of their normal flora It is the most virulent of the species in the genus It grows on sheep blood agar
Humans harbor the organism as part of their normal flora
Foodborne outbreaks of brucellosis are most commonly associated with eating Raw shellfish Imported cheese Contaminated potato salad Improperly cooked hamburger
Imported cheese
Which group of tests, along with colonial morphology on primary media, aids most in the rapid identification of the Enterobacteriaceae? MR and VP, urease, and blood agar plate Phenylalanine deaminase, urease, and CDC agar plate Bacitracin, β-lactamase, and MacConkey agar plate Indole, oxidase, MacConkey, and blood agar plates
Indole, oxidase, MacConkey, and blood agar plates
Legionella pneumophila Infections are most often acquired from environmental sources Metabolizes a number of carbohydrates Stains easily on the routine Gram stain Does not autofluoresce
Infections are most often acquired from environmental sources
Direct spread of pneumonic plague disease occurs by which route? Fecal-oral route Rat bite Ingestion of contaminated tissue Inhalation of contaminated airborne droplets
Inhalation of contaminated airborne droplets
Penicillin is active against bacteria by Inhibition of protein synthesis at the 30S ribosomal subunit Reduction of dihydrofolic acid Inhibition or peptidoglycan synthesis Inhibition of nucleic acid function
Inhibition or peptidoglycan synthesis
Brucella spp. are Hide answer choices The etiologic agents of relapsing fever Small spiral organisms Primarily a cause of endogenous human infections Intracellular pathogens
Intracellular pathogens
Buffered charcoal yeast extract agar is the recommended medium for the recovery of Hafnia alvei Legionella pneumophilia Neisseria meningitidis Vibrio cholerae
Legionella pneumophilia
Which agar that is used for routine stool cultures is the medium of choice for the isolation of Yersinia strains from stool specimens? Salmonella-Shigella agar Hektoen enteric agar MacConkey agar CNA agar
MacConkey agar
SITUATION: A group of elementary students became ill after eating undercooked ground beef prepared in the school cafeteria. The suspected pathogen, E. coli serotype 0157:H7, is usually recovered using which of the following media? XLD agar MacConkey agar MacConkey agar with sorbitol Hektoen agar
MacConkey agar with sorbitol
SITUATION: Several attendees of a medical conference in the Gulf coast area became ill after frequenting a seafood restaurant. A presumptive identification of Vibrio cholera was made after stool specimens from several subjects grew clear colonies on MacConkey agar and yellow colonies on TCBS agar. Which key tests would help eliminate Aeromonas and Plesiomonas spp.? Mannitol fermentation, Na+ requirement Correct answer Oxidase, motility Oxidase, nitrate Hemolysis on blood agar, catalase
Mannitol fermentation, Na+ requirement
The nitrate reduction test is used to determine the ability of an organism to reduce nitrate. The Enterobacteriaceae group can reduce nitrate. Based on this test, what is the end product for which nitrate is reduced? CO2 NH3 O2 N2
N2
The classic toxigenic strains of which serogroup are implicated in epidemic infections of Vibrio choleare? O1 O2 O3 O4
O1
Which of the following is not a correct description regarding Aeromonas hydrophila? Beta-hemolytic Catalase positive ONPG negative Oxidase positive
ONPG negative
Metronidazole is most commonly recommended for treatments of infections caused by Aerobic microorganisms Microaerophilic microorganisms Obligate anerobic microorganisms Obligate intercellular microorganisms
Obligate anerobic microorganisms
Which is the best rapid test to differentiate Plesiomonas shigelloides from a Shigella species on selective enteric agar? Oxidase Correct answer Indole TSI Urease
Oxidase
Smooth gray colonies showing no hemolysis are recovered from an infected cat scratch on blood and chocolate agar but fail to grow on MacConkey agar. The organisms are gram-negative pleomorphic rods that are both catalase and oxidase positive and strongly indole positive. The most likely organism is: Capnocytophaga spp. Pasteurella spp. Proteus spp. Pseudomonas spp.
Pasteurella spp.
Why might it be necessary for both pink (lactose-positive) and colorless (lactose-negative) colonies from an initial stool culture on MacConkey agar to be subcultured and tested further for possible pathogens? Most Shigella strains are lactose positive Most Salmonella strains are maltose negative Most Proteus spp. are lactose negative Pathogenic E. coli can be lactose positive or lactose negative
Pathogenic E. coli can be lactose positive or lactose negative
An example of a halophilic microorganism is Morganella morganii Plesiomonas shigelloides Vibrio parahaemolyticus Correct answer Yersinia pestis
Vibrio parahaemolyticus
Explosive watery diarrhea with severe abdominal pain after eating raw shellfish is most characteristic of infection caused by Campylobacter jejuni Helicobacter pylori Shigella dysenteriae Vibrio parahemolyticus
Vibrio parahemolyticus
Vibrio vulnificus is a well-established human pathogen that is known to cause Gastroenteritis Pneumonia Pyelonephritis Wound infections
Wound infections
Cold enrichment of feces (incubation at 4°C) in phosphate-buffered saline prior to subculture onto enteric media enhances the recovery of: Enterotoxigenic E. coli Salmonella paratyphi Hafnia alvei Y. enterocolitica
Y. enterocolitica
Assume you perform microbiology for an institution submitting surveillance cultures for MRSA. Which isolate should receive further workup to rule out methicillin (oxacillin) resistance? On Baird Parker agar, a gray brownish colony with no clear zone. Gram-positive cocci in clusters, catalase positive. Black colonies on Chromagar. Catalase-positive, Gram-positive cocci in clusters. Yellow colonies on Mannitol Salt agar; catalase-positive, coagulase-positive. Clear colonies on Mannitol Salt agar; catalase-positive, coagulase-negative.
Yellow colonies on Mannitol Salt agar; catalase-positive, coagulase-positive.
Enterobacter sakazakii can best be differentiated from Enterobacter cloacae by which of the following characteristics? Yellow pigmentation and negative sorbitol fermentation Pink pigmentation and positive arginine dihydrolase Yellow pigmentation and positive urease H2S production on TSI
Yellow pigmentation and negative sorbitol fermentation
Which of the 2 different antimicrobial agents listed below are commonly used and may result in synergistic action in the treatment of endocarditis caused by Enterocolcus faecalis? an aminoglycoside and a macrolide a penicillin derivative and an aminoglycoside a cell membrane active agent and nalidixic acid a macrolide and a penicillin derivative
a penicillin derivative and an aminoglycoside
A Klebsiella pneumoniae isolate is known to produce carbapenemase; therefore, it therapeutically will not respond to the antibiotics: amoxicillin, cefazolin and imipenem colistin and rifampin sulfamethoxazole and trimethoprim-sulfamethoxazole tetracycline and doxycycline
amoxicillin, cefazolin and imipenem
Representative beta-lactam antibiotics and their mechanism of action include: ampicillin, cefazolin and imipenem; and inhibition of cell wall synthesis ampicillin, cefazolin and imipenem; and inhibition of DNA replication ciprofloxacin, levofloxacin and aztreonam; and inhibition of cell wall synthesis ciprofloxacin, levofloxacin and aztreonam; and inhibition of DNA replication
ampicillin, cefazolin and imipenem; and inhibition of cell wall synthesis
In disk diffusion susceptibility testing, as an antimicrobial agent diffuses away from the disk, the concentration of antibiotic is: increased decreased unchanged inoculum dependent
decreased
A stool from a 2-year-old girl grew clear colonies on MacConkey agar, red colonies on XLD (without black centers), and green colonies on HE (without black centers). It is ornithine positive and indole negative. It should agglutinate in antisera of which serogroup of the somatic O antigen? A B C D
D
Which are the best two tests to differentiate A. hydrophilia from Pleisomonas shigelloides? Oxidase and motility DNase and VP Indole and lysine decarboxylase Growth on MacConkey and blood agar
DNase and VP
A suspension of the test organism for use in broth dilution and disk diffusion testing is adjusted to match the turbidity of a Hide answer choices #0.5 McFarland Standard #1.0 McFarland Standard #2.0 McFarland Standard #3.0 McFarland Standard
#0.5 McFarland Standard
Sulfonamides, such as sulfamethoxazole (SMZ), and trimethoprim (TMP), work by targeting: Penicillin-binding proteins; disrupting bacterial cell wall synthesis Tetrahydrofolate synthesis; preventing bacterial DNA synthesis 30S ribosomal subunits; inhibiting bacterial protein translation 50S ribosomal subunits; inhibiting bacterial protein translation
30S ribosomal subunits; inhibiting bacterial protein translation
At which pH does the methyl red (MR) test become positive? 7.0 6.5 6.0 4.5
4.5
Which culture agar combinations below will be MOST sufficient for routine urine culture investigations? 5% sheep blood and Chocolate 5% sheep blood and MacConkey 5% sheep blood and Thayer-Martin MacConkey and Eosin Methylene Blue
5% sheep blood and MacConkey
The minimum bactericidal concentration (MBC) of an antimicrobial agent is defined as the lowest concentration of that antimicrobial agent that kill at least ______ of the original inoculum. 95.5% 97% 99.9% 100%
99.9%
Which of the following is true concerning Campylobacter jejuni? Catalase negative Isolated best at 24C Hydrogen sulfide positive A leading cause of bacterial diarrhea worldwide
A leading cause of bacterial diarrhea worldwide
Kingella denitrificans can be differentiated from Neisseria gonorrhoeae because it is Able to grow on Thayer-Martin agar Able to reduce nitrates Oxidase positive Glucose positive
Able to reduce nitrates
Which of the following variables may change the results of an MIC? Inoculum size Incubation time Growth rate of the bacteria All of these options
All of these options
A patient is being treated with gentamicin for a Gram-negative bacterial infection. The chemistry department has repeating peak and trough orders on the patient. Which of the following antibiotic classes does gentamicin belong to? Aminoglycosides Beta-lactams Fluoroquinolones Polymyxins
Aminoglycosides
Which class of antibiotics is used for the treatment of serious gram-negative infections as well as infections with Mycobacterium tuberculosis? Cephalosporins Penicillins Tetracyclines Aminoglycosides
Aminoglycosides
An elderly woman who cared for several domestic cats was hospitalized with suspected cat-scratch disease (CSD). Blood cultures appeared negative, but a small, slightly curved pleomorphic gram-negative bacillus grew on BHI agar (brain, heart infusion agar with 5% horse or rabbit blood). What is the most likely identification? Bartonella spp Brucella spp Kingella spp Haemophilus spp
Bartonella spp
Clavulanic acid is classified as Beta-lactam Beta-lactamase inhibitor Macrolide Aminoglycoside
Beta-lactamase inhibitor
A 5-year-old nonimmunized male with a persistent cough, fever, and flulike symptoms was admitted to the hospital. Nasopharyngeal swabs were cultured on 15% blood, chocolate, Bordet-Genjou, and Regan-Lowe (with 10% charcoal) agars. All media grew a gram-negative coccobacillus. Carbohydrate and biochemical tests were negative. What is the most likely identification? Haemophilus influenza Bordetella pertussis Haemophilus parainfluenzae Bordetella bronchiseptica
Bordetella pertussis
Which of the following is the optimal clinical specimen for the recovery of Legionella pneumophilia? Stool Blood Bronchial washings Nasopharyngeal swab
Bronchial washings
The species of Campylobacter noted to produce septicemia, septic arthritis, meningitis, jaundice with hepatomegaly, and thrombophlebitis in debilitated patients is C. coli C. fetus Correct answer C. laris C. sputorum
C. fetus
The HACEK group of organisms (Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella spp.) are all known for which type of infection? Urinary tract Endocarditis Pharyngitis Tonsillitis
Endocarditis
A suspected case of Legionnaires' disease was noted on the request form for a culture and sensitivity ordered on a sputum sample. The patient was a 70-year-old male who presented with a positive serological test for Legionella spp. What is the most efficient way to confirm the infection using the submitted sample? Culture the sputum on MacConkey agar Gram stain of the sputum Acid-fast staining Direct immunofluorescent microscopy
Direct immunofluorescent microscopy
Which of the following organisms are generally positive for β-galactosidase? Salmonella spp. Shigella spp. Proteus spp. E. coli
E. coli
A 6-year-old female patient was admitted to the hospital following 2 days of severe diarrhea. Cultures from three consecutive stool samples contained blood and mucus. Patient history revealed a hamburger lunch at a fast-food restaurant 3 days earlier. Which pathogen is most likely responsible for the following results? Growth on: XLD agar = yellow colonies HE agar = yellow colonies Mac agar = light pink and dark pink colonies Mac with sorbitol agar - few dark pink and many colorless colonies Salmonella spp Shigella spp E. coli O157:H7 Yersinia enterocolitica
E. coli O157:H7
The majority of clinical laboratories with a microbiology department should have the capability of serotyping which pathogenic Enterobacteriaceae? Yersinia enterocolitica, Shigella spp E. coli O157:H7, Salmonella spp., Shigella spp Yersinia pestis, Salmonella spp Edwardsiella spp., Salmonella spp
E. coli O157:H7, Salmonella spp., Shigella spp
Xylose lysine deoxycholate (XLD) agar is a highly selective medium used for the recovery of which bacteria? Staphylococcus spp. from normal flora Yersinia spp. that do not grow on Hektoen agar Enterobacteriaceae from gastrointestinal specimens Streptococcus spp. from stool cultures Microbiology/Select methods/Reagents/Media/Stool culture/1
Enterobacteriaceae from gastrointestinal specimens
Resistance to clindamycin can be induced in vitro by Ampicillin Erythromycin Gentamicin Penicillin
Erythromycin
Which of the following microorganisms is LEAST likely to produce a capsule or slime layer? Escherichia coli Klebsiella pneumoniae Streptococcus pneumoniae Pseudomonas aeruginosa
Escherichia coli
Which genera of the Enterobacteriaceae are known to cause diarrhea and are considered enteric pathogens? Enterobacter, Klebsiella, Providencia, and Proteus Escherichia, Salmonella, Shigella, and Yersinia Pseudomonas, Moraxella, Acinetobacter, and Aeromonas Enterobacter, Citrobacter, and Morganella
Escherichia, Salmonella, Shigella, and Yersinia
Which microorganism will grow only on culture media supplemented with either cysteine or cystine? Actinobacillus lignieresii Bartonella bacilliformis Francisella tularensis Kingella kingae
Francisella tularensis
A tech receives a request for VRE colonization testing on a patient in the hospital. Which of the following is an appropriate area of the body for culture for screening? Anterior nares Rectal area Groin Urine
Rectal area
When using the rapid chromogenic cephalosporin method for the detection of beta-lactamase production by an organism, a positive test is indicated by the color Yellow Green Red Blue
Red
Lysine iron agar (LIA) showing a purple slant and a blackened butt indicates: E. coli Citrobacter spp Salmonella spp Proteus spp
Salmonella spp
Which of the following is not one of the standard control organisms used for the weekly testing of antimicrobial disks? Staphylococcus epidermidis(ATCC 25833) Pseudomonas aeruginosa(ATCC 27853) Escherichia coli(ATCC 25922) Enterococcus faecalis(ATCC 29212)
Staphylococcus epidermidis(ATCC 25833)
Which of the following organisms would not routinely undergo antimicrobial susceptibility testing? Escherichia coli Proteus mirabilis Staphylococcus aureus Streptococcus pyogenes
Streptococcus pyogenes
Which one of the following organisms dos not require susceptibility testing to the antimicrobial indicated when isolated from a clinically significant source? Staphylococcus aureus clindamycin Proteus mirabilis gentamicin Streptococcus pyogenes penicillin Escherichia coli levofloxacin
Streptococcus pyogenes penicillin
The chemotherapeutic agents structurally similar to the vitamin p-aminobenzoic acid that act by inhibiting bacteria via inhibition of folic acid synthesis are Aminoglycosides Penicillins Macrolides Sulfonamides
Sulfonamides
The term that denotes a situation in which the effect of two antimicrobial agents together is greater than the sum of the effects of either drug alone is Additivism Antagonism Sensitivity Synergism
Synergism
The breakpoint of an antimicrobial drug refers to The amount needed to cause bacteriostasis A minimum inhibitory concentration (MIC) of 16 μg/mL or greater A MIC of 64 μg/mL or greater The level of drug that is achievable in serum
The level of drug that is achievable in serum
In this image is a quadrant plate containing brain heart infusion agar supplemented with 6 µg/mL of vancomycin. The right upper quadrant was inoculated with the test strain of Enterococcus faecium. The presence of growth in the inoculated quadrant indicates ___________? The organism is susceptible to vancomycin The organism is not E. faecium. The organism is resistant to vancomycin The plate is contaminated and a repeat should be performed.
The organism is resistant to vancomycin
When performing the oxidase test, which of the following would not be appropriate? The reagent used is o-nitrophenyl-B-D-galactopyranoside A nichrome wire loop should be used to acquire inoculum for testing Colonies from sheep blood agar can be used A positive colony turns dark purple within 10 seconds after application of the reagent
The reagent used is o-nitrophenyl-B-D-galactopyranoside
Which of the following statements is not true of Brucella? Infection may occur via abrasions of the oral mucosa, conjunctiva, and genitals They are fastidious and require supplemented media for isolation The risk of accidental laboratory infection is no greater than with any other organism Phage and dye sensitivity tests are used for identification to the species level
The risk of accidental laboratory infection is no greater than with any other organism
An example of bactericidal antibiotic is Chloramphenicol Erythromycin Tetracycline Tobramycin
Tobramycin
Kligler iron agar (KIA) differs from triple-sugar iron agar (TSI) in the: Ratio of lactose to glucose Ability to detect H2S production Use of sucrose in the medium Color reaction denoting production of acid
Use of sucrose in the medium
Which of the following antimicrobial agents acts by inhibiting cell wall synthesis? Clindamycin Gentamicin Naladixic acid Vancomycin
Vancomycin
A quality control procedure on a new batch of Mueller-Hinton agar plates using a Staphylococcus aureus ATCC strain and incubation in ambient air resulted in all the disk zone sizes measuring too small. The most likely reason for this is that the: Hide answer choices Mueller-Hinton plates were poured too thin potency of the antibiotic disks is too high bacterial suspension was not diluted to the proper concentration incubation should have been in a 5-10% CO2 atmosphere
bacterial suspension was not diluted to the proper concentration
Penicillin resistance in Neisseria gonorrhoeae can be due to the organism producing: beta-D-galactosidase beta-lactamase butyrate esterase DNase
beta-lactamase
The organisms Klebsiella pneumoniae, Enterobacter cloacae, and Escherichia coli can produce carbapenemases due to which of the following genes? mec A van A blaKPC erm
blaKPC
When performing antimicrobial susceptibility testing on Enterobacteriaceae, first- generation cephalosporins can be adequately represented by cefuroxime ceftriaxone cefazolin cefonicid
cefazolin
An antibiotic used to suppress or kill contaminating fungi in media is: amphotericin B penicillin chloramphenicol cycloheximide streptomycin
cycloheximide
An Enterobacteriaceae organism will appear to be more resistant on a disk diffusion susceptibility test if the depth of the agar is too thin inoculum is too concentrated the antimicrobial agent in disk is too concentrated test interpretation occurs after 12 hours of ambient air incubation
inoculum is too concentrated
Oxacillin resistance in clinical strains of staphylococci is confirmed by the detection of the _______ gene. vanA vanB mecA mefA
mecA
The lowest concentration of antibiotic that inhibits growth of a test organism is the: minimum bactericidal concentration minimum inhibitory concentration serum bactericidal concentration serum inhibitory concentration
minimum inhibitory concentration
The most sensitive substrate for the detection of beta-lactamases is: penicilin ampicilin cefoxitin nitrocefin
nitrocefin
An antibiotic that inhibits cell wall synthesis is: chloramphenicol colistin penicillin sulfamethoxazole
penicillin
The procedure that assures the most accurate detection of mecA-mediated oxacillin resistance in routine broth microdilution susceptibility testing against S aureus is: addition of 4% NaCI incubation at 30°C incubation for 48 hours testing with cefoxitin
testing with cefoxitin
An isolate of E. coli recovered from the stool of a patient with severe bloody diarrhea should be tested for which sugar before sending it to a reference laboratory for serotyping? Sorbitol (fermentation) Mannitol (oxidation) Raffinose (fermentation) Sucrose (fermentation)
Sorbitol (fermentation)
Eikenella corrodens is an opportunistic pathogen, but it is the most noted for causing Hide answer choices Abscesses of the oral cavity Pneumonia Postsurgical wound infections Urinary tract infections
Abscesses of the oral cavity
When an unknown member of the Enterobacteriaceae family is recovered in primary culture, which key characteristics would lead you to suspect Klebsiella pneumoniae? Indole production Absence of motility Positive ornithine decarboxylase Positive phenylalanine deaminase
Absence of motility
The Voges-Proskauer (VP) test detects which end product of glucose fermentation? Acetoin Nitrite Acetic acid Hydrogen sulfide
Acetoin
Which genus (in which most species are oxidase and catalase positive) of small gram-negative coccobacilli is associated mainly with animals but may cause endocarditis, bacteremia, as well as wound and dental infections in humans? Actinobacillus Pseudomonas Campylobacter Vibrio
Actinobacillus
Identify the fermentative agent that may infect reptiles and fish as well as humans when they are exposed to contaminated soil or water Aeromonas Correct answer Chromobacterium Chryseobacterium Enterobacter
Aeromonas
A fermentative gram-negative bacillus that is oxidase positive, motile, and grows well on MacConkey agar is Aeromonas hydrophila Correct answer Pseudomonas aeruginosa Stenotrophomonas maltophilia Yersinia enterocolitica
Aeromonas hydrophila
SITUATION: Abdominal pain, fever, vomiting, and nausea prompted an elderly male to seek medical attention. A watery stool specimen producing no fecal leukocytes or erythrocytes was cultured and grew a predominance of gram-negative fermentative bacilli. The colonies were beta-hemolytic on blood agar and cream colored on MacConkey agar. The colonies were both oxidase and catalase positive. What is the Aeromonas hydrophilia Escherichia coli Salmonella spp Shigella spp
Aeromonas hydrophilia
A suspected case of plague requires which of the following procedures in order to confirm Yersinia pestis? Collection of multiple sets of blood cultures Incubation of blood cultures at both 28°C and 35°C Culture aspirates from bubos to MacConkey agar at room temperature All of these options
All of these options
Illustrated in the left tube of this photograph is a positive Voges Proskauer reaction (left tube). The red pigment is produced from the reactions of: Alpha naphthol with acetoin (dimethyl carbinol) Alpha naphthol with diacetyl Potassium hydroxide with acetoin (dimethyl carbinol) Pyruvate with acetoin (dimethyl carbinol)
Alpha naphthol with diacetyl
Decarboxylation of the amino acids lysine, ornithine, and arginine results in the formation of: Ammonia Urea CO2 Amines
Amines
In the test for urease production, ammonia reacts to form which product? Ammonium citrate Ammonium carbonate Ammonium oxalate Ammonium nitrate
Ammonium carbonate
A positive Simmons citrate test is seen as a: Blue color in the medium after 24 hours of incubation at 35°C Red color in the medium after 18 hours of incubation at 35°C Yellow color in the medium after 24 hours of incubation at 35°C Green color in the medium after 18 hours of incubation at 35°C
Blue color in the medium after 24 hours of incubation at 35°C
A gram-negative S-shaped rod recovered from selective media for Campylobacter species gave the following results: Catalase = + Oxidase = + Motility = + Hippurate hydrolysis = + Growth at 42°C = + Nalidixic acid = Susceptible Pigment = Neg Grape odor = Neg Cephalothin = Resistant The most likely identification is: Pseudomonas aeruginosa Campylobacter jejuni Campylobacter fetus Pseudomonas putida
Campylobacter jejuni
Fever, abdominal cramping, watery stools, and fluid and electrolyte loss preceded by bloody stools 2-3 days before is characteristic of shigellosis but may also result from infection with: Campylobacter spp Salmonella spp Proteus spp Yersinia spp
Campylobacter spp
A 46-year-old dog warden was admitted to the hospital with several puncture bite wounds encountered while wrangling with a stray dog. Culture at 48 hours produced small yellow colonies on 5% sheep blood and chocolate agars in 10% CO2, but no growth on MacConkey agar. Gram stain showed gram-negative curved, fusiform rods. Colonies were oxidase and catalase positive. What is the most likely identification? Capnocytophaga canimorsus Francisella tularensis Legionella pneumophila Pseudomonas aeruginosa
Capnocytophaga canimorsus
Cultures obtained from a dog bite wound produced yellow, tan, and slightly pink colonies on blood and chocolate agar with a margin of fingerlike projections appearing as a film around the colonies. Given the following results at 24 hours, which is the most likely organism? Oxidase = + Catalase = + Growth on MacConkey agar = Neg Motility = Neg Actinobacillus spp. Eikenella spp. Capnocytophaga spp Pseudomonas spp.
Capnocytophaga spp
Care must be taken when identifying biochemical isolates of Shigella because serological cross reactions occur with: E. coli Salmonella spp Pseudomonas spp Proteus spp
E. coli
Four blood cultures were taken over a 24-hour period from a 20-year-old woman with severe diarrhea. The cultures grew motile (room temperature), gram-negative rods. A urine specimen obtained by catheterization also showed gram-negative rods, 100,000 col/mL. Given the following results, which is the most likely organism? TSI = A/A gas Indole = + VP = Neg MR = + H2S = Neg Citrate = Neg Urease = Neg Lysine decarboxylase = + Phenylalanine deaminase = Neg Proteus vulgaris Salmonella typhi Yersinia enterocolitica E. coli
E. coli
The Shiga-like toxin (verotoxin) is produced mainly by which Enterobacteriaceae? Klebsiella pneumoniae E. coli Salmonella typhimurium Enterobacter cloacae
E. coli
A mixture of slender gram-negative rods and coccobacilli with rounded ends was recovered from blood cultures following a patient's root canal surgery. Given the following results after 48 hours, what is the most likely organism? Catalase = Neg Ornithine decarboxylase = + Urease = Neg Lysine decarboxylase = + Oxidase = + X and V requirement = Neg Indole = Neg Carbohydrates = Neg (no acid produced) Growth on blood and chocolate agar = + (with pitting of agar) Growth on MacConkey agar = Neg Eikenella corrodens Actinobacillus spp. Cardiobacterium hominis Proteus spp.
Eikenella corrodens
Kingella kingae is usually associated with which type of infection? Middle ear Endocarditis Meningitis Urogenital
Endocarditis
Which Enterobacteriaceae is the most common cause of uncomplicated urinary tract infections (UTIs)? Proteus mirabilis Klebsiella oxytoca Escherichia coli Pseudomonas aeruginosa
Escherichia coli
Biochemically, the Enterobacteriaceae are gram-negative rods that: Ferment glucose, reduce nitrate to nitrite, and are oxidase negative Ferment glucose, produce indophenol oxidase, and form gas Ferment lactose and reduce nitrite to nitrogen gas Ferment lactose and produce indophenol oxidase
Ferment glucose, reduce nitrate to nitrite, and are oxidase negative
Which of the following has a negative oxidase test? Aeromonas Chryseobacterium Hafnia Vibrio
Hafnia
Select the primary and differential media of choice for recovery of most fecal pathogens MacConkey, blood, birdseed, and Campylobacter (Campy) agars Hektoen, MacConkey, Campy, blood agar CNA and Christensen urea agars and thioglycollate media Blood, Campy, Mueller-Hinton agars, and thioglycollate media
Hektoen, MacConkey, Campy, blood agar
Infection of the gastric mucosa leading to gastritis or peptic ulcers is most commonly associated with Campylobacter jejuni Helicobacter pylori Correct answer Salmonella Typhi Shigella sonnei
Helicobacter pylori
Campylobacter jejuni is Nonmotile Oxidase negative Hippurate hydrolysis positive Correct answer A straight gram-negative bacillus
Hippurate hydrolysis positive
Which group of tests best differentiates Enterobacter aerogenes from Edwardsiella tarda? Motility, citrate, and urease Hydrogen sulfide (H2S) production, sucrose fermentation, indole, and VP Lysine decarboxylase, urease, and arginine dihydrolase Motility, H2S production, and DNase
Hydrogen sulfide (H2S) production, sucrose fermentation, indole, and VP
Which of the following tests may be used to differentiate Cardiobacterium hominis from Actinobacillus spp.? Gram stain Indole Anaerobic incubation Oxidase
Indole
Which single test best separates Klebsiella oxytoca from K. pneumoniae? Urease Sucrose Citrate Indole
Indole
Cardiobacterium hominis, as inhabitant of the upper respiratory tract of humans, has been recovered as the etiologic agent from cases of endocarditis. An identifying characteristic of the organism is Positive oxidase Positive catalase Indole negative Inability to grow on sheep blood agar
Indole negative
Which one of the following statements about E.coli O157:H7 is false? It has been reported in contaminated unpasteurized milk, unpasteurized apple juice, and undercooked hamburger It can cause hemolytic-uremic syndrome (HUS) in children It causes hemorrhagic diarrhea, abdominal pain, and other symptoms It ferments sorbitol rapidly
It ferments sorbitol rapidly
Which of the following is not characteristic of Eikenella corrodens? It is a thin, gram-negative bacillus Colonies sometimes pit the surface of the agar medium It is found in the mouth and upper respiratory tract of humans It is often found in pure culture when recovered from infections
It is often found in pure culture when recovered from infections
Which of the following organism is unable to grow on MacConkey agar? Bordetella bronchiseptica Burkholderia cepacia Kingella denitrificans Plesiomonas shigelloides
Kingella denitrificans
A leg culture from a nursing home patient grew gram-negative rods on MacConkey agar as pink to dark pink oxidase-negative colonies. Given the following results, which is the most likely organism? TSI = A/A Indole = Neg MR = Neg VP = + Citrate = + H2S = Neg Urease = + Motility = Neg Antibiotic susceptibility: resistant to carbenicillin and ampicillin Serratia marcescens Proteus vulgaris Enterobacter cloacae Klebsiella pneumoniae
Klebsiella pneumoniae
Which of the following tests best differentiates Shigella species from E. coli? Hydrogen sulfide, VP, citrate, and urease Lactose, indole, ONPG, and motility Hydrogen sulfide, MR, citrate, and urease Gas, citrate, and VP
Lactose, indole, ONPG, and motility
Infections caused by Yersinia pestis are rare in the United States. Those cases that do occur are most frequently located in which region? New Mexico, Arizona, and California Alaska, Oregon, and Utah North and South Carolina and Virginia Ohio, Michigan, and Indiana
New Mexico, Arizona, and California
Which of the following is not true regarding virulent strains of Vibrio cholerae? Adherent to enterocytes Mucinase production Nonmotile Toxigenic
Nonmotile
In the Kauffmann-White schema, the combined antigens used for serological identification of the Salmonella spp. are: O antigens H antigens Vi and H antigens O, Vi, and H antigens
O, Vi, and H antigens
A bloody stool cultured from a 26-year-old woman after 3 days of severe diarrhea showed the following results at 48 hours after being plated on the following media: MacConkey agar: little normal flora with many non-lactose-fermenting colonies Hektoen enteric agar: many blue-green colonies Campylobacter blood agar and C. difficile agar: no growth Clear colonies (from MacConkey agar) tested negative for oxidase, indole, urease, motility, and H2S The most likely identification is: Shigella spp. Salmonella spp. Proteus spp. E. coli
Shigella spp.
The ortho-nitrophenyl-β-galactopyranoside (ONPG) test is most useful when differentiating: Salmonella spp. from Pseudomonas spp Shigella spp. from some strains of Escherichia coli Klebsiella spp. from Enterobacter spp Proteus vulgaris from Salmonella spp
Shigella spp. from some strains of Escherichia coli
A tech is working on a urine culture and finds the following isolates: Escherichia coli: >100,000 CFU/mL Staphylococcus epidermidis: 5,000 CFU/mL How should the tech continue with the culture workup? Perform sensitivity on E. coli and list the S. epidermidis as a contaminant Perform sensitivity testing on both organisms Quantitate culture and report as mixed urethral flora/contaminants Perform sensitivity testing on S. epidermidis and list E. coli as a contaminant
Perform sensitivity on E. coli and list the S. epidermidis as a contaminant
Which genera of Enterobacteriaceae are usually nonmotile at 36°C? Shigella, Klebsiella, and Yersinia Escherichia, Edwardsiella, and Enterobacter Proteus, Providencia, and Salmonella Serratia, Morganella, and Hafnia
Shigella, Klebsiella, and Yersinia
Which of the following organisms, found in normal fecal flora, may be mistaken biochemically for the genus Yersinia? Klebsiella spp Proteus spp E. coli Enterobacter spp
Proteus spp
Three blood cultures taken from a 30-year-old cancer patient receiving chemotherapy and admitted with a urinary tract infection grew lactose-negative, motile, gram-negative rods prior to antibiotic therapy. Given the following biochemical reactions, which is the most likely organism? H2S (TSI) = + Indole = + MR = + VP = Neg Citrate = Neg Urease = + DNase = + Phenylalanine deaminase = + Gelatin hydrolysis = + Ornithine decarboxylase = Neg Proteus vulgaris Proteus mirabilis Serratia marcescens Klebsiella pneumoniae
Proteus vulgaris
Which species of Shigella is most commonly associated with diarrheal disease in the United States? S. dysenteriae S. flexneri S. boydii S. sonnei
S. sonnei
The malonate test is most useful in differentiating which members of the Enterobacteriaceae? Shigella Proteus Salmonella subgroups 2, 3 (the former Arizona) Serratia
Salmonella subgroups 2, 3 (the former Arizona)
A routine, complete stool culture procedure should include media for the isolation of E. coli O157:H7 as well as: Salmonella, Shigella, Yersinia, Campylobacter, and Staphylococcus aureus Vibrio cholerae, Brucella, and Yersinia spp S. aureus, group B streptococci, and group D streptococci Clostridium difficile, Clostridium perfringens, and Yersinia spp
Salmonella, Shigella, Yersinia, Campylobacter, and Staphylococcus aureus
A leg-wound culture from a hospitalized 70-year-old diabetic man grew motile, lactose-negative colonies on MacConkey agar. Given the following biochemical reactions at 24 hours, what is the most probable organism H2S (TSI) = Neg Indole = Neg MR = Neg VP = + DNase = + Citrate = + Urease = Neg Phenylalanine deaminase = Neg Ornithine and lysine decarboxylase = + Arginine decarboxylase = Neg Gelatin hydrolysis = + Proteus vulgaris Serratia marcescens Proteus mirabilis Enterobacter cloacae
Serratia marcescens
The positive phenylalanine deaminase reaction seen in the left tube (green pigmentation in the slant compared to the negative control on the right) may be produced by each of the following bacterial species EXCEPT: ***Just concentrate on the information given deaminase positive***, I know it does not look like the one seen in the lab (wine color) Proteus vulgaris Serratia marcescens Morganella morganii Providencia stuartii
Serratia marcescens
All of the following Enterobacteriaceae below are appropriately matched with the characteristic listed, EXCEPT: Escherichia coli - indole positive Citrobacter freundii - H2S positive Serratia marscens - Voges-Proskauer negative Klebsiella pneumoniae - indole negative
Serratia marscens - Voges-Proskauer negative
Kingella kingae can best be differentiated from Eikenella corrodens using which medium? Sheep blood agar Chocolate agar MacConkey agar XLD agar
Sheep blood agar
Illustrated in this photograph, reading from left to right, are tubes of Kligler Iron agar (KIA), Sulfide Indole Motility agar, indole broth, Voges Proskauer broth and Simmons citrate. The bacterial species most likely producing the reactions illustrated here is: **TSI k/a, motility: negative, indole: negative, citrate negative, MR + Shigella sonnei Escherichia coli Yersinia frederikensii Providencia stuartii
Shigella sonnei
The appearance of the bacterial colonies growing on the surface of the Hektoen Enteric (HE) agar plate shown in the photograph to the right are consistent with all of the following bacterial species EXCEPT: Serratia marcesens Shigella sonnei Klebsiella oxytoca Enterobacter sakasakii
Shigella sonnei
The enterotoxins of both Vibrio cholerae O1 and noninvasive (toxigenic) strains of Escherichia coli produce serious diarrhea by what mechanism? Hide answer choices Stimulation of adenylate cyclase, which gives rise to excessive fluid secretion by the cells of the small intestine Penetration of the bowel mucosa Stimulation of colicin production Elaboration of a dermonecrotizing toxin
Stimulation of adenylate cyclase, which gives rise to excessive fluid secretion by the cells of the small intestine
A visitor to South America who returned with diarrhea is suspected of being infected with V. cholerae. Select the best medium for recovery and identification of this organism MacConkey agar Blood agar TCBS agar Correct answer XLD agar
TCBS agar
A stool culture from a 30-year-old man suffering from bloody mucoid diarrhea gave the following results on differential enteric media: MacConkey agar = clear colonies; XLD agar = clear colonies; Hektoen agar = green colonies; Salmonella-Shigella agar = small, clear colonies Which tests are most appropriate for identification of this enteric pathogen? TSI, motility, indole, urease, Shigella typing with polyvalent sera TSI, motility, indole, lysine, Salmonella typing with polyvalent sera TSI, indole, MR, VP, citrate TSI, indole, MR, and urease
TSI, motility, indole, urease, Shigella typing with polyvalent sera
When performing the oxidase test, which of the following would not be appropriate? The reagent used is o-nitrophenyl-B-D-galactopyranoside Correct answer A nichrome wire loop should be used to acquire inoculum for testing Colonies from sheep blood agar can be used A positive colony turns dark purple within 10 seconds after application of the reagent
The reagent used is o-nitrophenyl-B-D-galactopyranoside
All of the following are true about all members of the Enterobacteriaceae, EXCEPT: Hide answer choices They are all gram-negative They are all oxidase-positive They are all bacilli They all ferment glucose
They are all oxidase-positive
For the selective isolation of Vibrio spp. the recommended agar is Thiosulfate-citrate-bile sault-sucrose-agar Correct answer Charcoal yeast extract agar Mannitol salt agar Tinsdale agar
Thiosulfate-citrate-bile sault-sucrose-agar
Select the media of choice for recovery of Vibrio cholerae from a stool specimen MacConkey agar and thioglycollate media Thiosulfate-citrate-bile-sucrose (TCBS) agar and alkaline peptone water (APW) broth Correct answer Blood agar and selenite-F (SEL) broth CNA agar
Thiosulfate-citrate-bile-sucrose (TCBS) agar and alkaline peptone water (APW) broth
Which group of tests best differentiates Helicobacter pylori from C. jejuni? Catalase, oxidase, and Gram stain Catalase, oxidase, and nalidixic acid sensitivity Catalase, oxidase, and cephalothin sensitivity Urease, nitrate, and hippurate hydrolysis
Urease, nitrate, and hippurate hydrolysis
The species of Vibrio closely associated with rapidly progressing wound infections seen in patients with underlying liver disease is V. alginolyticus V. cholerae V. vulnificus V. parahaemolyticus
V. vulnificus
Fecal cultures are inoculated on thiosulfate-citrate-bile salts-sucrose agar specifically for the isolation of Shigella Vibrio Campylobacter Salmonella
Vibrio
The symptom of diffuse, watery diarrhea that produces a relatively clear stool containing mucus flecks is suggestive of an infection caused by Enterohemorrhagic Escherichia coli Shigella dysenteriae Vibrio cholerae Correct answer Yersinia enterocolitica
Vibrio cholerae
A curved gram-negative rod producing oxidase-positive colonies on blood agar was recovered from a stool culture. Given the following results, what is the most likely identification? Lysine decarboxylase = + Arginine decarboxylase = Neg Indole = + KIA = Alk/Acid VP = Neg Lactose = Neg Urease = ± String test = Neg TCBS agar = Green colonies Vibrio cholerae Vibrio parahaemolyticus Shigella spp. Salmonella spp.
Vibrio parahaemolyticus
Three consecutive stool cultures from a 25-year-old male patient produced scant normal fecal flora on MacConkey and Hektoen agars. However, colonies on CIN agar (cefsulodin-irgasan-novobiocin) displayed "bulls-eye" colonies after 48 hours incubation. The patient had been suffering from enterocolitis with fever, diarrhea, and abdominal pain for 2 days. What is the most likely identification of this gram-negative rod? E. coli Proteus mirabilis Yersinia enterocolitica Klebsiella pneumoniae
Yersinia enterocolitica
Following a 2-week camping trip to the Southwest (US), a 65-year-old male patient was hospitalized with a high fever and an inflammatory swelling of the axilla and groin lymph nodes. Several blood cultures were obtained, resulting in growth of gram-negative rods resembling "closed safety pins." The organism grew on MacConkey's agar showing non-lactose-fermenting colonies. Testing demonstrated a nonmotile rod that was biochemically inert. What is the most likely identification? Yersinia pestis Klebsiella pneumoniae Proteus vulgaris Morganella morganii
Yersinia pestis
What bacteria is responsible for the bubonic plague? Mycobacterium tuberculosis Yersinia pestis Vibrio cholerae Corynebacterium diphtheriae
Yersinia pestis
The supervisor of a microbiology laboratory has been asked to begin performing in vitro antimicrobial susceptibility testing of Mycobacterium tuberculosis because of an increase in reported resistance in his community. Which of the following methods would be appropriate for this testing? Broth microdilution method using Mueller-Hinton brother Kirby-Bauer method BACTEC method Schlichter method
BACTEC method
In addition to CO2 requirements and biochemical characteristics, Brucella melitensis and Brucella abortus are differentiated by growth on media containing which two dyes? Basic fuchsin and thionin Methylene blue and crystal violet Carbol fuchsin and iodine Safranin and methylene blue
Basic fuchsin and thionin
A tech working in the laboratory receives a VRE screening culture. Which of the following agars should the tech use to set up the VRE screening culture? Bile-esculin-azide (BEA) agar with vancomycin Columbia Nalidixic acid (CNA) agar MacConkey agar Buffered Charcoal yeast extract (BYCE) agar
Bile-esculin-azide (BEA) agar with vancomycin
Which medium is recommended for the recovery of Brucella spp. from blood and bone marrow specimens? Biphasic Castenada bottles with Brucella broth Blood culture bottles with Brucella broth Bordet-Gengou agar plates and THIO broth Blood culture bottles with THIO broth
Biphasic Castenada bottles with Brucella broth
In suspected cases of brucellosis, the optimal specimen to be collected for the isolation of the etiologic agent is Blood Urine Cerebrospinal fluid Nasopharyngeal exudates
Blood
Chloramphenicol is an important antimicrobial agent for the treatment of meningitis as well as several other serious infections. Unfortunately, chloramphenicol exhibits significant complications that limit its clinical usefulness. These effects include Allergic reactions and anaphylaxis Bone marrow suppression and aplastic anemia Significant gastrointestinal manifestations Photosensitivity
Bone marrow suppression and aplastic anemia
Which media should be used to recover Bordetella pertussis from a nasopharyngeal specimen? Chocolate agar Blood agar MacConkey agar Bordet-Gengou agar
Bordet-Gengou agar
Which medium is best for recovery of Legionella pneumophila from clinical specimens? Chocolate agar Bordet-Gengou agar New yeast extract agar Buffered charcoal-yeast extract (CYE) agar
Buffered charcoal-yeast extract (CYE) agar
When testing the antimicrobial susceptibility of Haemophilus influenzae strains by disk-agar diffusion, the recommended medium is Chocolate agar Charcoal yeast extract agar Mueller-Hinton base supplemented with 5% sheep blood Mueller-Hinton base supplemented with hematin, NAD, and yeast extract
Mueller-Hinton base supplemented with hematin, NAD, and yeast extract
Members of the genus Cedecea are best differentiated from Serratia spp. by which test result? Positive motility Positive urease Positive phenylalanine deaminase Negative DNase
Negative DNase
Shigella species generally exhibit which of these characteristics? Urease positive Non-motile Oxidase positive Lactose fermentation
Non-motile
Which of the following tests should be done first in order to differentiate Aeromonas spp. from the Enterobacteriaceae? Hide answer choices Urease OF glucose Oxidase Correct answer Catalase
Oxidase
Which of the following species of Pasteurella is associated with human infections following cat bites? P. avium P. canis P. multocida P. stomatis
P. multocida
In case of legionellosis Person-to-person transmission is common Farm animals are important animal reseroirs Patients can present with a self-limited nonpneumonic febrile illness Specimens may be cold enriched to enhance recovery of the organism
Patients can present with a self-limited nonpneumonic febrile illness
Beta-lactamase-producing strains of Haemophilus influenzae are resistant to Chloramphenicol Erythromycin Penicillin Trimethoprim sulfamethoxazole
Penicillin
Putrescine is an alkaline amine product of which bacterial enzyme? Arginine decarboxylase Phenylalanine deaminase Lysine decarboxylase
Phenylalanine deaminase
Legionella pneumophila is the etiologic agent of both Legionnaires disease and Swine fever Pontiac fever Rift Valley fever San Joaquin Valley fever
Pontiac fever
A tech receives a call from the floor regarding antimicrobial therapy. The patient culture yielded an aerobic Gram-positive coccus and the physician would like to use an antibiotic that inhibits RNA synthesis. Which of the following antibiotics would be the best choice? Ciprofloxacin Ceftazidime Vancomycin Rifampin
Rifampin
According to the Kirby-Bauer standard antimicrobial susceptibility testing method, what should be done when interpreting the zone size of a motile, swarming organism such as a Proteus species? The swarming area should be ignored The results of the disk diffusion method are invalid The swarming area should be measured as the growth boundary The isolate should be retested after diluting to a 0.05 McFarland standard
The swarming area should be ignored
When performing a disk diffusion susceptibility test, the antibiotic disks are placed on the agar 30 minutes after organism inoculation and then incubated within 15 minutes of the disk placement. This procedure will result in: the antibiotic not diffusing into the medium, resulting in no zone decreased zone diameters increased zone diameters no effect on the final zone diameter
decreased zone diameters
Susceptibility testing performed on quality control organisms using a new media lot number yielded zone sizes that were too large for all antibiotics tested. The testing was repeated using media from a previously used lot number, and all zone sizes were acceptable. The unacceptable zone sizes are best explained by the: antibiotic disks were not stored with the proper desiccant depth of the media was too thick depth of the media was too thin antibiotic disks were not properly applied to the media
depth of the media was too thin
Antibiotics routinely tested and reported for Pseudomonas aeruginosa isolates include: clindamycin erythromycin gentamicin Incorrect: penicillin
gentamicin
Which of the following reagents is added to detect the production of indole? p-Dimethylaminobenzaldehyde Bromcresol purple Methyl red Cytochrome oxidase
p-Dimethylaminobenzaldehyde