Biology Exam Bank Questions with Solutions: Staphylococcus, Streptococcus, and Bacillus, Exams of Biology

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The most frequent agent of nosocomial bacteremia is: A. catalase-negative micrococci. B. coagulase-positive staphylococci. C. catalase-negative stomatococci. D. coagulase-negative staphylococci - Correct solution D The species of Staphylococcus, which is one of the most important human pathogens, is: A. S. lentus. B. S. aureus. C. S. mucilaginosus. D. S. intermedius - Correct solution B Which group of bacteria is described as catalase positive and is gram- positive cocci that grow facultatively anaerobic and form grapelike clusters? A. Neisseria B. Rothia (stomatococci) C. Staphylococcus D. Micrococcus - Correct solution C The first identification test performed on a clinical isolate of gram-positive, catalase-positive cocci would likely be the: A. penicillin test. B. Gram stain. C. oxidase test. D. coagulase test - Correct solution D The slide coagulase test is a rapid screening test for the production of: A. clumping factor. B. free coagulase. C. extracellular coagulase. D. catalase. - Correct solution A

A tube coagulase test was performed on catalase-positive, gram-positive cocci that were beta hemolytic and grew on mannitol salt agar. The tube was checked after overnight incubation and was negative. Which of the following statements explains this discrepancy? A. A tube coagulase should not be performed on a catalase-positive organism. B. A beta-hemolytic colony, which is catalase positive and grows on mannitol salt, is normally coagulase negative. C. The test should have been read in 1 to 4 hours in case any hemolysins are present. D. No discrepancy is present; the results are accurate - Correct solution C The tube coagulase test: A. detects bound coagulase. B. detects extracellular coagulase. C. is performed on slide coagulase-positive isolates to confirm a positive result. D. requires citrated reagent plasma - Correct solution B In clinical isolates, the most likely identification of coagulase-positive, catalase-positive, gram-positive cocci that are penicillin resistant would be: A. Staphylococcus aureus. B. Staphylococcus intermedius. C. Stomatococcus luteus. D. Micrococcus aureus - Correct solution A Which virulent and important human pathogen can also be recovered from the nares, perineum, and other skin sites of healthy people, especially in the hospital setting? A. Micrococcus luteus B. Staphylococcus intermedius C. Staphylococcus aureus D. All Micrococcaceae - Correct solution C The resident human flora, staphylococcus, which is more likely to cause infections in compromised hosts such as patients with cancer, is: A. S. saprophyticus. B. S. aureus. C. S. epidermidis.

D. S. intermedius - Correct solution C The Staphylococcaceae staphylococcus that is more likely to cause uncomplicated urinary tract infections in nonhospitalized hosts, especially sexually active young women, is: A. S. saprophyticus. B. S. aureus. C. S. epidermidis. D. S. intermedius. - Correct solution A Isolates of coagulase-negative Staphylococcus from urinary tract infections can be presumptively identified as S. saprophyticuson the basis of its: A. penicillin susceptibility. B. novobiocin resistance. C. penicillin resistance. D. novobiocin susceptibility - Correct solution B Quality control should be performed on which two organisms to determine the validity of the oxidase reagent? A. Staphylococcus aureus and S. epidermidis B. S. epidermidis and Enterococcus C. Aerococcus and Enterococcus D. Micrococcus and Aerococcus - Correct solution D An infected intravenous (IV) catheter tip grew out gram-positive cocci, which were catalase positive and coagulase negative. The zone size of the novobiocin disk measured 18 mm. The most likely organism causing infection is: A. Staphylococcus saprophyticus. B. S. epidermidis. C. S. hominis. D. S. cohnii - Correct solution B Which organism is catalase positive, coagulase negative, pyrrolidonyl arylamidase (PYR) positive, susceptible to novobiocin, urease negative, and beta hemolytic on sheep blood agar? A. Staphylococcus epidermidis B. S. saprophyticus C. S. cohnii D. S. haemolyticus - Correct solution D

Which of the following organisms best describes a catalase-negative, gram-positive coccus that is beta-hemolytic on sheep blood agar? A. Streptococcus pyogenes B. S. pneumoniae C. Staphylococcus epidermidis D. Micrococcaceae spp - Correct solution A Which species of bacteria is responsible for causing diseases such as rheumatic fever, glomerulonephritis, and exudative pharyngitis? A. Streptococcus agalactiae B. S. pyogenes C. S. pneumoniae D. Enterococcus - Correct solution B Streptococcus pneumoniae can be described as: A. resistant to bile and optochin. B. beta-hemolytic. C. catalase-positive. D. often carrying an antiphagocytic capsule. - Correct solution D The colonial morphologic features of this organism resemble a donut as it ages, and it has a polysaccharide capsule that is responsible for its virulence. What two characteristics describe this organism? A. Beta-hemolytic and susceptible to optochin B. Alpha-hemolytic and bile solubility-negative C. Gamma-hemolytic and resistant to optochin D. Alpha-hemolytic and bile solubility-positive - Correct solution D The development of acute rheumatic fever and subsequent valvular heart disease are problems that may be encountered by patients infected with: A. Enterococcus faecalis. B. Streptococcus pneumoniae. C. S. pyogenes. D. S. agalactiae. - Correct solution C The development of glomerulonephritis is a problem that may be encountered by patients infected with: A. Enterococcus faecalis. B. Streptococcus pneumoniae.

C. S. pyogenes. D. S. agalactiae - Correct solution C Erythrogenic toxin, hyaluronidase enzyme, and hemolysins S and O are extracellular products of: A. Enterococcus faecalis. B. Streptococcus pneumoniae. C. S. pyogenes. D. S. agalactiae - Correct solution C The bacterial species that can be described as able to hydrolyze hippurate, is beta-hemolytic, is a major cause of neonatal meningitis and sepsis, and is a producer of the Christie, Atkins, Munch-Petersen (CAMP) factor is: A. Enterococcus faecalis. B. Streptococcus pneumoniae. C. S. pyogenes. D. S. agalactiae. - Correct solution D The CAMP factor is produced by: A. Enterococcus faecalis. B. Streptococcus pneumoniae. C. S. pyogenes. D. S. agalactiae. - Correct solution D The major etiologic agent of bacterial endocarditis in the United States is: A. Enterococcus faecalis. B. Streptococcus pneumoniae. C. S. pyogenes. D. viridans streptococci. - Correct solution D Enterococci can be described as: A. able to hydrolyze bile esculin. Correct B. usually beta-hemolytic. C. a major cause of pharyngitis. D. often carrying an antiphagocytic capsule - Correct solution A The bacterial species that can be described as able to grow in 6.5% sodium chloride (NaCl) and 40% bile, is part of the normal fecal flora of animals and humans, is usually nonhemolytic, and is a major cause of nosocomial infections is:

A. Enterococcus faecalis. B. Streptococcus pneumoniae. C. S. pyogenes. D. S. agalactiae. - Correct solution A Generally speaking, nutritionally variant streptococci require what ingredient not found in most conventional media? A. Vitamin B B. Nalidixic acid and its components C. Nicotinamide adenine dinucleotide (NAD) enrichment D. Blood or blood products - Correct solution A What morphologic feature is a major consideration in determining an identification scheme for streptococci? A. Colony shape and color B. Hemolytic pattern C. Smell D. Consistency - Correct solution B What name is given to the type of hemolysis that produces incomplete hemolysis and a greening discoloration of the medium? A. Beta hemolysis B. Gamma hemolysis C. Alpha hemolysis D. Kappa hemolysis - Correct solution C What name is given to the type of hemolysis that produces complete hemolysis and a clearing of the medium? A. Beta hemolysis B. Gamma hemolysis C. Alpha hemolysis D. Kappa hemolysis - Correct solution A Differentiation of the pleomorphic strains of streptococci and the similar corynebacteria or lactobacilli can be best accomplished by: A. examination of Gram stain of the colony. B. vancomycin-susceptibility testing. C. serologic testing. D. examination of the morphologic features after growth in thioglycollate broth. - Correct solution D

Bacitracin, pyrrolidonyl arylamidase (PYR), CAMP factor, and hippurate are tests most likely performed on a(n) _______Streptococcus. A. alpha-hemolytic B. beta-hemolytic C. nonhemolytic D. gamma-hemolytic - Correct solution B Optochin, PYR, bile solubility, esculin, and 6.5% NaCl are tests most likely performed on a(n) _______ Streptococcus. A. alpha-hemolytic B. beta-hemolytic C. nonhemolytic D. gamma-hemolytic - Correct solution A The drugs of choice for most enterococcal infections are: A. vancomycin and a penicillin. B. clindamycin and vancomycin. C. penicillin and an aminoglycoside. D. septra. - Correct solution C Media that can be used for isolating Bacillus anthracis include: A. Thayer-Martin agar. B. 5% sheep blood agar. C. MacConkey agar. D. Columbia blood agar with colistin-nalidixic acid (CNA). - Correct solution B Suspect spore-forming, gram-positive Bacillus species that is nonhemolytic, nonmotile, and penicillin-susceptible and that produces a wide zone of lecithinase on egg yolk agar can be identified as: A. Corynebacterium diphtheria. B. Bacillus anthracis. C. Bacillus cereus. D. Corynebacterium jeikeium - Correct solution B Induction of sporulation by Bacillus species can be accomplished with _____ agar. A. 5% sheep blood B. PLET acetate

C. bicarbonate D. urea - Correct solution D Induction of capsule formation by B. anthracis can be accomplished with _____ agar. A. 5% sheep blood B. PLET acetate C. bicarbonate D. urea - Correct solution C Which of the following is described as a spore-forming, gram-positive Bacillus that is beta-hemolytic, motile, Voges-Proskauer (VP)-positive, and citrate-positive and causes two types of food poisoning as a result of toxin release? A. Corynebacterium diphtheria B. Bacillus anthracis C. Bacillus cereus D. Corynebacterium jeikeium - Correct solution C A U.S. Food and Drug Administration (FDA)-cleared immunochromatographic test produces a red line on the cassette and can presumptively identify which gram-positive Bacillus that is nonhemolytic and morphologically has a "Medusa head" appearance when grown on 5% sheep blood agar? A. Bacillus subtilis B. B. cereus C. B. mycoides D. B. anthracis - Correct solution D A gram-positive Bacillus, which is beta-hemolytic on 5% sheep blood agar, produces a wide zone of lecithinase on egg yolk agar, is nonmotile, and was isolated from the stool of a patient with abdominal pain and watery diarrhea. Because of the patient's existing immunocompromised state, the physician administered penicillin as the antibiotic therapy. The patient's condition did not improve after 7 days of treatment. Which one of the following statements explains the reason for the antibiotic failure? A. The course was too abbreviated and should be given for 14 days. B. The patient may be allergic to penicillin and its therapeutic effects. C. Penicillin is ineffective against gram-positive organisms.

D. The organism produces beta-lactamase, which renders the drug inactive. - Correct solution D Which of the following types of anthrax occurs after ingesting the spores and affects the abdominal or oropharyngeal area? (Patients usually die from toxemia and overwhelming sepsis.) A. Cutaneous B. Pulmonary C. Gastrointestinal D. Bubonic - Correct solution C A patient diagnosed with Bacillus anthracis is allergic to penicillin. Which antibiotic can be given that will be therapeutically effective? A. Ampicillin B. Ciprofloxacin C. Imipenem D. Vancomycin - Correct solution B Enzyme-linked immunosorbent assays (ELISAs) are available that can serologically identify which Bacillus species? A. B. cereus B. B. subtilis C. B. thuringiensis D. B. anthracis - Correct solution D Not including organisms in the Enterobacteriaceae family, the second most common gram-negative bacilli encountered in clinical specimens are: A. Pseudomonas. B. Burkholderia. C. Ralstonia. D. Vibrio. - Correct solution A Production of exotoxin A and several proteolytic enzymes and hemolysins are factors that contribute to the pathogenicity of which organism? A. Pseudomonas aeruginosa B. Burkholderia cepacia C. Ralstonia pickettii D. Burkholderia mallei - Correct solution A

The disease referred to as melioidosis is caused by which one of the following? A. Pseudomonas aeruginosa B. Ralstonia pickettii C. Burkholderia mallei D. Burkholderia pseudomallei - Correct solution D A convenient and reliable identification scheme for Pseudomonas aeruginosa involves which of the following conventional tests? A. Oxidase, triple sugar iron (TSI) slant, growth at 42° C on Mueller-Hinton agar or trypticase soy agar B. Catalase, lysine iron agar (LIA) slant, growth at 42° C on Mueller-Hinton agar or trypticase soy agar C. Oxidase, TSI slant, growth at 24° C on Mueller-Hinton agar or trypticase soy agar D. Catalase, TSI slant, growth at 42° C on sheep blood agar or blood trypticase soy agar - Correct solution A An organism described as oxidase-positive, (K/NC) on TSI media, growth at 42° C, and produces a bright bluish-green pigment on Mueller-Hinton agar is most likely: A. Pseudomonas aeruginosa. B. Ralstonia pickettii. C. Burkholderia mallei. D. Burkholderia pseudomallei - Correct solution A Which two organisms should be used to determine the validity of urea agar for quality control purposes? A. Pseudomonas fluorescens and Burkholderia cepacia complex B. Ralstonia mannitolilytica and Acidovorax delafieldii C. Brevundimonas diminuta and Brevundimonas vesicularis D. Brevundimonas vesicularis and Ralstonia pickettii - Correct solution D Which species of Burkholderia is the one most commonly found in clinical specimens? A. Burkholderia ralstonia B. Burkholderia pseudomallei C. Burkholderia mallei D. Burkholderia cepacia - Correct solution D

Which best describes the source of Burkholderia cepacia infections? A. Rice paddles B. Medical devices C. Oropharynx of animals D. Rodents - Correct solution B Which organism exhibits bipolar staining on the Gram stain, which resembles a "safety-pin" appearance? A. Burkholderia mallei B. Pseudomonas pseudomallei C. The Centers for Disease Control and Prevention (CDC) group D. Brevundimonas diminuta - Correct solution B Oxidative-fermentative base-polymyxin B-bacitracin-lactose (OFPBL) media is the best media to use to isolate which one of the following organisms from the sputa of patients with cystic fibrosis? A. Pseudomonas pseudomallei B. Ralstonia pickettii C. Burkholderia cepacia D. Acidovorax delafieldii - Correct solution C Pertussis (whooping cough), an epidemic disease, is a highly contagious, acute infection of the upper respiratory tract caused by the _________ species. A. Brucella B. Bordetella C. Pasteurella D. Francisella - Correct solution B The mode of transmission of Bordetella bronchiseptica can best be described as: A. person-to-person contact. B. exposure to contaminated water. C. inhalation of contaminated air. D. close contact with animals. - Correct solution D Gram-stain morphologic features, motility, and flagellar placement are important identifying characteristics of: A. Chryseobacterium. B. Flavobacterium.

C. Pseudomonas. D. Bordetella. - Correct solution D Quality control is set up to determine the validity of cetrimide agar. Which two organisms should be used? A. Bordetella bronchiseptica and Cupriavidus pauculus B. Achromobacter denitrificans and Alcaligenes faecalis C. Achromobacter piechaudii and Bordetella bronchiseptica D. Centers for Disease Control and Prevention (CDC) Alcaligenes-like group 1 and Cupriavidus pauculus - Correct solution C The mode of transmission of Achromobacter denitrificans can best be described as: A. person-to-person contact. B. exposure to contaminated water. C. contaminated fluids or medical solutions. D. close contact with animals. - Correct solution C Achromobacter, Alcaligenes, and Bordetella are all: A. urea-positive. B. oxidase-negative. C. nonglucose utilizers. D. lactose fermenters. - Correct solution C Which of the following statements best describes the habitats of Achromobacter, Alcaligenes, and Bordetella? A. The habitats are limited to the upper respiratory tract of various mammals. B. The habitats vary from the soil and water environment to the upper respiratory tract of various mammals. C. The habitats are limited to the soil and water environment. D. The habitats are limited to the mucous membranes of humans and animals - Correct solution B The organism most frequently associated with various infections in humans is: A. Bordetella. B. Oligella. C. Achromobacter. D. Roseomonas. - Correct solution C

The biochemical description of Bordetella bronchiseptica is: A. oxidase-positive, motile, and rapid urease-positive. B. indole-positive, nonmotile, and has a fruity odor. C. resistant to vancomycin and will grow on MacConkey agar at 42° C. D. nonmotile and both urea-positive and phenylalanine deaminase-positive

• Correct solution A The biochemical description of Myroides is: A. oxidase-positive, motile, and rapid urease-positive. B. urease-positive and has a fruity odor. C. resistant to vancomycin and will grow on MacConkey agar at 42° C. D. nonmotile and both urea-positive and phenylalanine deaminase-positive
• Correct solution B Stool specimens suspected of containing which of the following enteric pathogens should be collected and transported only in Cary-Blair medium because buffered glycerol saline is toxic for this bacterium? A. Vibrio B. Salmonella C. Shigella D. Plesiomonas - Correct solution A The selective medium, thiosulfate citrate bile salts sucrose (TCBS) agar, is especially formulated for isolating what pathogen from stool cultures? A. Vibrio B. Salmonella C. Shigella D. Plesiomonas - Correct solution A The reagent used in the "string test" is: A. bile solubility. B. sodium deoxycholate. C. bile esculin. D. 0/129 (2,4-diamino-6,7-diisopropylpteridine). - Correct solution B Vibrio cholera and V. alginolyticus appear what color on TCBS agar? A. Green B. Black C. Yellow

D. Blue - Correct solution C Colonies growing on modified cefsulodin-irgasan-novobiocin (CIN) agar appear to be either Aeromonas spp. or Yersinia enterocolitica. Which test should be performed to differentiate between these two organisms? A. String test B. Sucrose fermentation C. Glucose fermentation D. Oxidase - Correct solution D Vibrio cholerae and Photobacterium damsela are used to perform quality control on TCBS agar. After overnight incubation, no growth is observed. What is the next course of action? A. Reinoculate the TCBS agar, and incubate for 36 hours. B. Check the pH to ensure that it is 8.6. C. Reincubate the plates for another 24 hours. D. These two organisms are poor choices for quality control on TCBS agar

• Correct solution B An organism suspected of being one of the Vibrio spp. grew on MacConkey agar. To determine whether it was a vibrio cell or in the Enterobacteriaceae family, an oxidase test was performed on the colony. The results of the oxidase test, however, were negative. Which one of the following statements explains this discrepancy? A. The oxidase test should be performed on TCBS agar, not MacConkey agar. B. The oxidase test should be performed on a sheep blood agar plate to avoid false-negative results. C. The pH of the MacConkey agar is most likely elevated to alkaline conditions. D. No discrepancy is present. All vibrio cells are oxidase-negative - Correct solution B Which of the following statements best describes the habitats of Vibrio spp., Aeromonas spp., Plesiomonas shigelloides, andChromobacterium violaceum? A. Habitats are limited to the upper respiratory tract of various mammals. B. Habitats are limited to the gastrointestinal tract. C. Habitats are mostly soil and water environment. D. Habitats are limited mostly to soil. - Correct solution C

The primary habitat for Vibrio spp. is: A. fresh water. B. the upper respiratory tract of various mammals. C. brackish or marine water. D. the soil and water environment - Correct solution C A vibriostatic test using 0/129 (2,4-diamino-6,7-diisopropylpteridine)- impregnated disks differentiates vibrio cells, which are susceptible, and _________, which are resistant. A. Enterobacteriaceae B. Plesiomonas spp. C. aeromonads D. Chromobacterium spp - Correct solution C Which organism, which is oxidase positive, does not grow on TCBS agar, has the ability to decarboxylate lysine and ornithine but cannot utilize arginine, and would have the following colonial characteristics on sheep blood agar and MacConkey agar? A. Beta-hemolytic and is a nonlactose fermenter B. Alpha-hemolytic and is a lactose fermenter C. Gamma-hemolytic and is a nonlactose fermenter D. Alpha-hemolytic and is a nonlactose fermenter - Correct solution A Which of the following species of Aeromonas is oxidase-positive, sucrose- positive, and can decarboxylate ornithine? A. A. caviae B. A. schubertii C. A. hydrophila D. A. veronii biovar veronii - Correct solution D The transmission of Vibrio spp. to humans is by: A. exposure of disrupted skin and mucosal surfaces to contaminated animal hides. B. ingestion of contaminated seafood or water. C. inhalation of contaminated air. D. close contact with carriers of the organism - Correct solution B Transmission of Aeromonas spp. to humans is by:

A. exposure of disrupted skin and mucosal surfaces to contaminated animal hides. B. ingestion of contaminated seafood or water. C. inhalation of contaminated air. D. close contact with carriers of the organism - Correct solution B Transmission of Plesiomonas shigelloides to humans is by: A. exposure of disrupted skin and mucosal surfaces to contaminated animal hides. B. ingestion of contaminated seafood or water. C. inhalation of contaminated air. D. close contact with carriers of the organism - Correct solution B Transmission of Chromobacterium violaceum to humans is by: A. exposure of disrupted skin to contaminated water. B. ingestion of contaminated seafood or water. C. inhalation of contaminated air. D. close contact with carriers of the organism - Correct solution A The drug of choice to treat patients with Vibrio cholera is: A. tetracycline. B. ceftazidime. C. imipenem. D. aztreonam - Correct solution A To determine the validity of 0% sodium chloride (NaCl) broth, which two organisms should be used for quality control purposes? A. Vibrio alginolyticus and V. cincinnatiensis B. Photobacterium damsela and V. harveyi C. V. parahaemolyticus and V. cholerae D. V. vulnificus and P. damsela - Correct solution C Which organism appears green on TCBS agar and is halophilic? A. V. cholerae B. V. harveyi C. V. fluvialis D. V. vulnificus - Correct solution D

True cocci, such as most Neisseria spp. and Moraxella (Branhamella) catarrhalis, can be differentiated from morphologically similar Moraxella species by: A. comparing the penicillin susceptibility testing results of the bacteria. B. subjecting the bacterium to noninhibitory concentrations of penicillin. C. identifying the resistance of Moraxella to many beta-lactam antimicrobial agents. D. performing the deoxyribonucleic acid (DNA) test - Correct solution B The species of Moraxella that is most commonly associated with human infections, primarily of the respiratory tract, is: A. M. catarrhalis. B. M. lacunata. C. M. canis. D. M. atlantae - Correct solution A In Gram-stained preparations, Moraxella atlantae will appear as: A. either gram-negative coccobacilli or short, broad rods that tend to resist decolorization and may appear gram-variable. B. gram-negative cocci in pairs or short chains. C. coccobacilli or medium-sized rods. D. coccobacilli that may appear in chains - Correct solution A In Gram-stained preparations, Moraxella lacunata will appear as: A. either gram-negative coccobacilli or short, broad rods that tend to resist decolorization and may appear gram-variable. B. gram-negative cocci in pairs or short chains. C. coccobacilli or medium-sized rods. D. coccobacilli that may appear in chains - Correct solution C The virulence of this organism(s), which is transmitted via a dog bite, is attributed to: A. protease production. B. various toxins. C. hemolysins. D. something unknown. - Correct solution D Quality control should be performed on which two organisms to determine the validity of deoxyribonuclease (DNase) media? A. Moraxella atlantae and M. lacunata

B. M. lacunata and M. lincolnii C. M. nonliquefaciens and M. canis D. M. osloensis and M. lacunata - Correct solution C Testing for differentiation of Moraxella nonliquefaciens and M. osloensis can best be performed by: A. the ability to utilize acetate. B. the ability to liquefy serum. C. glucose utilization tests. D. growth on MacConkey agar - Correct solution A Testing for differentiation of Moraxella lacunata from other Moraxella species can best be performed by: A. the ability to utilize acetate. B. the ability to liquefy serum. C. glucose utilization tests. D. growth on MacConkey agar - Correct solution B Which organism appears clear on MacConkey agar and resembles some colonies of the Enterobacteriaceae family? A. Moraxella lacunata B. M. lincolnii C. M. canis D. M. nonliquefaciens - Correct solution C Which of the following tests can be performed to differentiate the two subspecies of Neisseria—elongata and glycolytica? A. Catalase B. Nitrate reduction C. DNase D. Growth in nutrient broth - Correct solution A With one exception, species of the genus Haemophilus require which of the following media ingredients for in vitro growth? A. Vitamin K and hemin B. Hemin and nicotine adenine dinucleotide (NAD) C. Vitamin K and NAD D. Hemin and cysteine - Correct solution B

Among H. influenzae strains, group designations (e.g., type b) are based on: A. flagellar antigens. B. capsular characteristics. C. cell wall antigens. D. infectious capabilities. - Correct solution B Chancroid is the sexually transmitted disease caused by: A. Haemophilus influenzae. B. H. ducreyi. C. H. aphrophilus. D. H. parainfluenzae - Correct solution B Which of the following media provides the factors necessary for the growth of Haemophilus spp.? A. 5% sheep blood agar B. Brain-heart infusion agar C. Chocolate agar D. Nutrient agar - Correct solution C In a phenomenon known as satelliting, tiny colonies of Haemophilus spp. may be observed growing on sheep blood agar close to colonies of: A. Streptococcus pyogenes. B. Staphylococcus aureus. C. Micrococcus spp. D. other Haemophilus spp - Correct solution B In a phenomenon known as satelliting, tiny colonies of Haemophilus spp. may be observed growing on sheep blood agar close to colonies of bacteria that can produce: A. hemin. B. NAD. C. vitamin K. D. cystine - Correct solution B Haemophilus ducreyi requires what special media to grow? A. Heart-infusion-based agar, supplemented with 10% IsoVitaleX and vancomycin B. Mueller-Hinton-based chocolate agar, supplemented with 1% IsoVitaleX and vancomycin

C. Heart infusion-based chocolate agar, supplemented with 10% fetal bovine serum and vancomycin D. Mueller-Hinton-based agar, supplemented with 10% IsoVitaleX and vancomycin - Correct solution B The sputum of a 75-year-old man with chronic lung infections yields the following:

• Many gram-negative coccobacilli in Gram stain
• X and V factors required for growth
• Nonhemolytic on rabbit blood agar The organism can be identified as: A. Haemophilus aegyptius. B. H. parainfluenzae. C. H. haemolyticus. D. H. influenzae. - Correct solution D Growth of most Haemophilus species in culture is enhanced by: A. incubation at 33° to 35° C. B. high humidity. C. 5% to 10% carbon dioxide (CO2). D. enriched special media - Correct solution C Performance of the "factor requirement test" for Haemophilus involves the: A. inoculation of unsupplemented media with a light suspension of the organism and placement of X and V factor disks on the agar surface B. inoculation of liquid media, unsupplemented and supplemented with X and V factors C. detection of the presence of enzymes that convert delta--aminolevulinic acid (ALA) into porphyrins. D. growth of the organism in the presence of bacterial species that produce X and V factors as metabolic byproducts. - Correct solution A Isolates from cerebrospinal fluid (CSF) or respiratory tract specimens that are gram-negative coccobacilli, grow on chocolate agar in CO2 but not on blood agar, and are porphyrin-negative and nonhemolytic on rabbit or horse blood may be identified as: A. Haemophilus parainfluenzae. B. H. parahaemolyticus. C. H. haemolyticus. D. H. influenzae. - Correct solution D

H. influenzae can be distinguished from H. aegyptius by its _____ test for _____. A. negative; sucrose fermentation B. negative; lactose fermentation C. positive; catalase D. positive; xylose fermentation - Correct solution D A 6-year-old boy was diagnosed with purulent conjunctivitis caused by a species of Haemophilus. What would the biochemical profile of the organism be? A. Growth requirements require both X and V factors; the organism is hemolytic on rabbit blood. B. Growth requirements require both X and V factors; the organism is nonhemolytic on rabbit blood. C. Growth requirements require V factor; the organism is hemolytic on rabbit blood. D. Growth requirements require X factor; the organism is nonhemolytic on rabbit blood - Correct solution A Although a useful test in the past, the particle agglutination assay for the detection of H. influenzae, type b, capsular polysaccharide antigen is no longer reliable because of: A. insufficiently high concentration of the organisms in clinical infections. B. a lack of sensitivity and specificity of the test procedure. C. the frequent use of antimicrobial therapy before collecting the specimen. D. the increased use of H. influenzae, type b, vaccination. - Correct solution D Of the following media, which provides the NAD necessary for the growth of Haemophilus spp.? A. 5% sheep blood agar B. Brain-heart infusion agar C. Chocolate agar D. Nutrient agar - Correct solution C Isolates from an ear swab that are gram-negative coccobacilli grow on chocolate agar in CO2 but not blood agar, require both X and V factors for growth, and are nonhemolytic on rabbit or horse blood may be identified as: A. Haemophilus parainfluenzae.

B. H. ducreyi. C. H. aphrophilus. D. H. influenzae. - Correct solution D Isolates from CSF that are gram-negative coccobacilli, grow on chocolate agar in CO2 but not blood agar, require factor V but not X, and are nonhemolytic on rabbit or horse blood may be identified as: A. Haemophilus parainfluenzae. B. H. influenzae. C. H. aphrophilus. D. H. ducreyi - Correct solution A To increase the sensitivity of direct Gram-stain examination of body fluid specimens, the specimens are usually: A. incubated for 18 to 24 hours before staining. B. centrifuged before staining. C. examined for at least 1 hour. D. stained for an additional 5 minutes - Correct solution B Which of the following opportunistic organisms is associated with slowly progressive subacute bacterial endocarditis? A. Haemophilus ducreyi B. H. influenzae C. Aggregatibacter aphrophilus D. H. parahaemolyticus - Correct solution C The virulence of this organism, which causes chancroid, is most likely attributed to: A. proteases. B. capsular factors. C. hemolysins. D. catalase - Correct solution B The majority of human infections with Campylobacter species are caused by: A. direct contact with carriers of the bacterium. B. contamination of food, milk, or water with animal feces. C. multiplication of the organism in food products. D. direct contact with persons infected with the bacterium - Correct solution B

Campylobacter spp. can sometimes be detected by direct Gram-stain examination of fecal sample, which would reveal many: A. large, faintly staining gram-negative bacilli. B. small curved or seagull-winged gram-negative bacilli. C. small gram-negative coccobacilli. D. plump, faintly staining gram-negative bacilli - Correct solution B Curved, microaerophilic, gram-negative rods, with most species having strong urease activity and the majority of which colonize mammalian stomachs or intestines, describe which group of bacteria? A. Campylobacter B. Helicobacter C. Arcobacter D. Enterobacter - Correct solution B Virulence determinants of Helicobacter pylori include: A. proteases. B. urease enzyme. C. hemolysins. D. exotoxins - Correct solution B Antimicrobial therapy for Helicobacter pylori infection consists of: A. penicillin, gentamycin, and imipenem. B. clindamycin, ceftriazone, and carbapenem. C. metronidazole, bismuth salt, and tetracycline. D. azithromycin alone - Correct solution C A gram-negative, spiral-shaped organism is isolated from a stool sample that was hippurate-positive, catalase-positive, susceptible to nalidixic acid, and resistant to cephalothin. The organism can be identified as: A. Campylobacter coli. B. C. jejuni subsp. doylei. C. C. jejuni subsp. jejuni. D. C. fetus subsp. fetus - Correct solution C Ensuring that all foods derived from animal sources are thoroughly cooked, all milk is pasteurized, and all drinking water is chlorinated are ways to avoid becoming infected with: A. Helicobacter.

B. Arcobacter. C. Enterobacter. D. Campylobacter. - Correct solution D Campylobacter jejuni subsp. jejuni grows best at what conditions? A. 37º C under microaerobic conditions B. 37º C under anaerobic conditions C. 42º C under microaerobic conditions D. 42º C under anaerobic conditions - Correct solution C Which of the following genes may attribute to the virulence of Helicobacter pylori by encoding for outer membrane proteins that mediate adherence to a specific blood group antigen on the surface of gastric epithelial cells? A. babA B. iceA C. cagA D. vacA - Correct solution A Which organisms should be used to perform quality control on hippurate reagent? A. Campylobacter coli and C. concisus B. C. curvus and C. hyointestinalis C. C. jejuni subsp. jejuni and C. jejuni subsp. doylei D. C. jejuni subsp. jejuni and C. coli - Correct solution D Individuals considered at greatest risk for contracting brucellosis are: A. dairy farmers. B. fishermen. C. prison guards. D. those working with exotic birds. - Correct solution A Facultative, intracellular parasitic bacteria are those that are able to: A. be cultured with or without oxygen but in cell cultures only. B. exist in both intracellular and extracellular environments. C. be cultured only with oxygen and in cell cultures. D. be cultured only inside living organisms such as mice. - Correct solution B Organisms belonging to the genus Brucella are: A. gram-positive diplococci.

B. gram-positive diphtheroid bacilli. C. gram-negative coccobacilli. D. gram-negative bacilli. - Correct solution C Although in vitro susceptibility testing is not reliable, which regimen of antibiotics is recommended for Brucella infections? A. Penicillin and azithromycin B. Ampicillin and gentamycin C. Doxycycline and rifampin D. Gentamycin and vancomycin - Correct solution C The animal reservoir for Brucella melitensis is: A. cattle. B. sheep or goats. C. swine. D. dogs - Correct solution B Pertussis (whooping cough) is an epidemic disease that is a highly contagious, acute infection of the upper respiratory tract caused by the: A. Brucella spp. B. Bordetella spp. C. Pasteurella spp. D. Francisella spp - Correct solution B The mode of transmission of Bordetella pertussis can best be described as: A. person-to-person contact. B. exposure to contaminated water. C. inhalation of contaminated air. D. close contact with animals. - Correct solution A During the catarrhal stage of pertussis, symptoms are: A. runny nose and mild cough. B. severe and violent coughing. C. vomiting and "whooping" as air is rapidly inspired into the lungs past a swollen glottis. D. lymphocytosis and fever. - Correct solution A During the paroxysmal stage of pertussis, symptoms are: A. runny nose and mild cough. B. severe and violent coughing.