CLS Micro Review Questions
Which of the following is associated with infections in humans often linked to deli meats and improperly pasteurized dairy products? A. Bacillus subtilis B. Listeria monocytogenes C. Leuconostoc D. Streptococcus agalactiae
B
Which of the following is not characteristic of L. monocytogenes? A. CAMP test positive B. Catalase negative C. Esculin hydrolysis positive D. Motile
B
Which of the following is most likely to be isolated in cultures from the anterior nares of healthcare workers? A. Bacillus cereus B. Streptococcus pneumoniae C. Staphylococcus aureus D. Staphylococcus saprophyticus
C
Which of the following nonfermenters is rarely isolated in the U.S.? A. Pseudomonas aeruginosa B. Stenotrophomonas maltophilia C. Burkholderia mallei D. Burkholderia cepacia
C
A fastidious GNR was isolated from a case of periodontal disease, which upon dark-field examination was noted to have gliding motility. The most likely identification of this etiologic agent would be...
Capnocytophaga
Streptococci are unable to synthesize the enzyme (___) which helps differentiate it from staph species.
Catalase
The sexually acquired disease characterized by genital ulcers and tender inguinal lymphadenopathy, which is caused by a small GNR, is known as...
Chancroid
An eenvironmental sampling study of respiratory therapy equipment produced cultures of yellow, nonfermentative (at 48 hours), GNR from several of the nebulizers, which would most likely be species of...
Chryseobacterium
Cystine-tellurite BAP is recommended for the isolation of...
Corynebacterium diphtheriae
Loeffler's serum medium is recommended for the cultivation of...
Corynebacterium diphtheriae
Tellurite reduction is used for the presumptive identification of...
Corynebacterium diphtheriae
The organism associated with a disease characterized by the presence of a pseudomembrane in the throat and the production of an exotoxin that is absorbed into the bloodstream with a lethal effect is...
Corynebacterium diphtheriae
An aerobic GPR known to cause bacteremia in hospitalized immunocompromised patients is...
Corynebacterium jeikeium
Pleomorphic GPR best describes...
Corynebacterium pseudophtheriticum
Colonies of Neisseria species turn color when a redox reagent is applied. The color change is indicative of the activity of the bacterial enzyme...
Cytochrome oxidase
S. saprophyticus, a recognized pathogen, is a cause of...
Urinary tract infections
The species of Vibrio closely associated with rapidly progressing wound infections seen in patients with underlying liver disease is...
V. vulnificus
Fecal cultures are inoculated on thiosulfate-citrate-bile salts-sucrose agar specifically for the isolation of...
Vibrio
The pulmonary form of anthrax is known as...
Woolsorter's disease
A common member of the normal flora of the upper respiratory tract is... A. Corynebacterium jeikeium B. Lactobacillus C. Staphylococcus epidermidis D. Viridans streptococcus
D
A negative PYR test is demonstrated by: A. Enterococcus faecalis B. Enterococcus faecium C. Streptococcus pyogenes D. Viridan streptococci
D
An example of an oxidase positive, glucose nonfermenting organism is... A. Aeromonas hydrophila B. E. coli C. K. pneumoniae D. Pseudomonas aeruginosa
D
The characteristics of being lactose negative, citrate negative, urease negative, lysine decarboxylase negative, and nonmotile best describe which organism? A. Proteus vulgaris B. Yersinia pestis C. Salmonella enterica D. Shigella dysenteriae
D
Which of the following diseases is most likely to be acquired from a hot tub or whirlpool? A. Q fever B. Erysipelas C. Acinetobacter cellulitis D. Pseudomonas dermatitis
D
Nocardia asteroides infections in humans characteristically produce...
Draining cutaneous sinuses
A culture of a decubitus ulcer grew a gram negative facultative bacillus. On TSI it produced an acid slant, acid butt, and gas. Test reations in other media were as follows: Citrate= Indole+ Urease= ONPG+ Voges-Proskauer= The organism was identified as...
E. coli
Precipitates of diphtheria toxin and antitoxin formed in agar gels are an in vitro means for detecting toxigenic strains of C. diphtheriae. The name of this test procedure is the...
Elek-test
A test for the hydrolysis of esculin in the presence of bile is especially useful in identifying species of which genus?
Enterococcus
A catalase-negative GPC is isolated from a urine sample of a hospitalized patient. The bacterium produced a black pigment on bile-esculine agar and formed acid from glucose in the presence of 6.5% NaCl. What is the most likely identification of this bacterium?
Enterococcus faecalis
Enterotoxin produced by Staphylococcus aureus is responsible for causing...
Enterocolitis
Bacillus cereus has been implicated as the etiologic agent in cases of...
Food poisoning
Which microorganism will grow only on culture media supplemented with either cysteine or cystine?
Francisella tularensis
Campylobacter spp. are associated most frequently with cases of...
Gastroenteritis
A causative agent of the form of conjunctivitis known as pinkeye is...
Haemophilus aegyptius
The K antigen of the family Enterobacteriaceae is...
Heat labile
Abiotrophia, formally known as nutritionally variant streptococci, will not grow on routine blood or chocolate agars because they are deficient in...
Pyridoxal
A former species of Corynebacterium pathogenic for swine, horses, and cattle is also known to cause disease in compromised hosts. This organism when grown on culture media produces pale pink colonies that help presumptively identify it as...
Rhodococcus equi
The beta-hemolysis produced by group A strep seen on the surface of a BAP is primarily the result of hemolysin...
S
In the CAMP test, a single streak of beta hemolytic Streptococcus is placed perpendicular to a streak of beta-lysin producing S. aureus. After incubation, a zone of increased lysis in the shape of an arrowhead is noted; this indicates the presumptive identification of...
S. agalactiae
A urine culture from a 23 year old female grew a catalase positive GPC, which would most likely be...
S. saprophyticus
Which of the following organisms would most likely produce the bichemical reactions shown in color plate 27?
Salmonella
Exfoliatin produced by S. aureus is responsible for causing...
Scalded skin syndrome
What disease involves erythrogenic toxin?
Scarlet fever
The Haemophilus influenzae vaccine protects against which serotype?
Serotype B
An organism occasionally misidentified as enteric pathogen because it produces a large amount of H2S is...
Shewanella putrefaciens
An infant was hospitalized with a severe, tender erythema. The child's epidermis was loose, and large areas of skin could be peeled off. The condition described is most consistent with a clinical syndrome associated with...
Staphylococcus aureus
Family members attending a picnic became ill about 2 hours after eating. the illness was characterized by rapid onset of violent vomiting. The most likely bacterial cause of such symptoms would be food poisoning caused by...
Staphylococcus aureus
The etiologic agent of the majority of adult joint infections is...
Staphylococcus aureus
The most common etiologic agent of infections associated with the surgical insertion of prosthetic devices such as artificial heart valves and CSF shunts is...
Staphylococcus epidermidis
The novobiocin susceptibility test is used for the identification of...
Staphylococcus saprophyticus
The enterotoxins of both Vibrio cholerae O1 and noninvasive (toxigenic) strains of E. coli produce serious diarrhea by what mechanisms?
Stimulation of adenylate cyclase, which gives rise to excessive fluid secretion by the cells of the small intestine
Colonies of Listeria monocytogenes on BAP most closely resemble colonies of...
Streptococcus agalactiae
The etiologic agent most commonly associated with septicemia and meningitis in newborns is...
Streptococcus agalactiae
Ethyllhydrocupreine HCl susceptibility is a presumptive test for the identification of...
Streptococcus pneumoniae
Rust colored sputum in cases of lobar pneumonia is characteristic of which etiologic agent?
Streptococcus pneumoniae
Solubility in the presence of sodium desoxycholate is characteristic of...
Streptococcus pneumoniae
A child presented in August at the pediatric clinic with a superficial skin infection of the neck. The large, itchy lesions were cultured, and the diagnosis of impetigo was made. One of the etiologic agents of this clinical condition is...
Streptococcus pyogenes
Cultures of the posterior pharynx are most commonly submitted to the clinical laboratory for the detection of...
Streptococcus pyogenes
The etiologic agent of the disease erysipelas is...
Streptococcus pyogenes
Streptococcus sanguis, a viridans streptococcus, is most commonly associated with which condition?
Subacute bacterial endocarditis
S. aureus, when present, could most likely be recovered from a stool sample if the primary plating medium included...
Phenylethyl alcohol
Legionella pneumophila is the etiologic agent of both Legionnaires disease and...
Pontiac fever
The single species in the genus Hafnia is...
alvei
The production of H2S is one characteristic used to differentiate which of the aerobic gram-positive bacilli? A. Corynebacterium B. Erysipelothrix C. Lactobacillus D. Nocardia
B
A fermentative GNR that is oxidase positive, motile, and grows well on MAC is... A. Aeromonas hydrophila B. Pseudomonas aeruginosa C. Stenotrophomonas maltophilia D. Yersinia enterocolitica
A
A gram-negative, "kidney-bean" cellular morphology is a distinguishing characteristic of... A. Neisseria menigitidis B. Yersinia pestis C. BArtonella spp. D. Actinobacter spp.
A
Color plate 26 shows the gram stain of a blood culture on a 23 year old pregnant woman who presented with fever and flu-like symptoms in her ninth month. The isolate on blood agar produced small, translucent beta-hemolytic colonies. Which of the following is most likely the etiologic agent? A. Listeria monocytogenes B. Propionibacterium acnes C. Streptococcus agalactiae D. Streptococcus pyogenes
A
Salmonella typhi exhibits a characteristic biochemical patter, which differentiates it from other salmonellae. Which of the following is not characteristic of S. typhi? A. Large amounts of H2S are produced in TSI agar B. Agglutination in Vi grouping serum C. Lysine decarboxykase positive D. Citrate negative
A
Which of the following is not associated with S. aureus? A. Endotoxin production B. Clumping factor production C. DNase production D. Hemolysin production
A
Which of the following is not true of Shigella sonnei? A. Large numbers of organisms must be ingested to produce disease? B. The organism produces an inflammatory condition in the large intestine with bloody diarrhea C. The organism produces disease most commonly in the pediatric population D. The organism is a delayed lactose fermenter
A
Which of the following organisms is able to hydrolyze sodium hippurate to benzoic acid and glycine? A. S. agalactiae B. S. pneumoniae C. L. monocytogenes D. E. faecalis
A
Which one of the following is not appropriate when describing Strep pneumo? A. Bile-resistant B. Alpha hemolytic C. Lancet shaped gram-positive diplococcus D. Virulent strains are encapsulated
A
An important characteristic of Neisseria gonorrhoeae or the infection it produces is...
Asymptomatic infections are common in females
Acinetobacter baumannii... A. Requires cysteine B. Is oxidase negative C. Ferments glucose D. Does not grow on MAC
B
Enterococcus faecium is characteristically... A. Inhibited by the presence of bile in culture media B. Able to grow in high salt concentrations C. PYR negative D. Beta-hemolytic
B
Erysipelothrix infections in humans characteristically produce...
Pathology at the point of entrance of the organism (Erysipeloid)
Which bacillus species is non-motile?
B. anthracis
What is the most commonly isolated species of Bacillus in opportunistic infections such as bacteremia, post-traumatic infections of the eye and endocarditis?
B. cereus
The causative agent of "malignant pustule" is...
Bacillus anthracis
The description of "Medusa head" colonies on solid agar is most characteristic of...
Bacillus anthracis
On Tinsdale agar, colonies of C. diphtheriae are characterized by the observance of...
Black colonies in the culture medium surrounded by brown halos
In suspected cases of brucellosis, the optimal specimen to be collected for isolation of the etiologic agent is...
Blood
In suspected cases of brucellosis, what is the most sensitive specimen to submit for culture?
Bone marrow
The etiologic agent of whooping cough is...
Bordetella pertussis
The causative agent of melioidosis is...
Burkholderia pseudomallei
A gram stain of a sputum specimen from a patient with a suspected case of lobar pneumonia reveals many WBCs and many GPC which are primarily diplococci. Which of the following statements would be appropriate, given these findings? A. A PYR test should be performed on the culture isolate B. An Elek test should be performed on the culture isolate C. An optichin test should be performed on the culture isolate D. A hippurate hydrolysis test should be performed on the culture isolate
C
An identifying characteristic of S. aureus is... A. DNase negative B. Coagulase negative C. Mannitol fermentation positive D. Growth inhibition in the presence of increased salt
C
Which of the following is a characteristic of staphylococci that would help in their isolation from clinical specimens? A. Bile resistance B. Growth at 55 degrees Celsius C. High salt tolerance D. Resistance to novobiocin
C
Which of the following is catalase negative? A. Bacillus B. Corynebacterium C. Leuconostoc D. Listeria
C
When an infection due to Streptomyces is suspected, isolates can be separated from most other bacteria by...
Incubating the culture at 25 degrees
The majority of clinical isolates of Klebsiella are...
K. pneumoniae
Streptococci obtain all their energy from the fermentation of sugars to...
Lactic acid
Neisseria lactamica closely resembles N. meningitidis but can be differentiated from it by its ability to metabolize...
Lactose
Growth in a 48 hour semisolid agar stab culture at room temperature reveals lateral filamentous growth away from the stab near the top of the medium. This observation is most characteristic of what organism?
Listeria monocytogenes
A gram-positive coccus that is catalase positive, nonmotile, lysostaphin resistant, and modified oxidase positive is best identified as a member of the genus...
Micrococcus
Erythromycin eye drops are routinely administered to infants to prevent infections by...
Neisseria gonorrhoeae
Severe DIC often complicates cases of septicemia caused by...
Neisseria menigitidis
A bone marrow transplant patient on immunosuppresive therapy developed a pulmonary abscess with symptoms of neurologic involvement. A brain abscess was detected by MRI, and aspirated material grew an aerobic, filamentous gram positive organism, which stained weakly acid-fast. The most likely etiologic agent in this case would be...
Nocardia asteroides
Nocardia can be differentiated from Actinomyces based on...
Nocardia being catalase positive
Streptococcus pyogenes can be presumptively identified using a(n)...
PYR disk
