Microbiology - Analytic Procedures For
Bacteriology Exam Study Guide
1. A Staphylococcus species recovered from a CSF shunt culture was found to
produce acid from sucrose and maltose and showed alkaline phosphatase
activity. The Staphylococcus was also coagulase negative. The most likely
identification is:
A. Staphylococcus epidermidis
B. Staphylococcus aureus
C. Staphylococcus schleiferi
D. Staphylococcus saprophyticus - ANSWER A
2. Isolates of nonmotile and nonpigmented enterococci that are resistant to
vancomycin can be assumed to have an acquired resistance by the transfer of
which of the following genes?
A. van A and van C genes
B. van B and van C genes
C. van A and van B genes
D. mec A and van C genes - ANSWER C
3. Some strains of Group F Strep can carry the group A antigen, potentially
leading to a false positive identification of group A, Streptococcus pyogenes. A
spot test that is helpful in differentiating these two species and thus preventing a
false report is:
A. Catalase
B. Bile solubility
C. Pyrrolidonyl-b-naphthylamide (PYR)
D. Cytochrome oxidase - ANSWER C
4. A tech is interpreting a urine culture from a catheter as the source. There is 1
colony of Staphylococcus epidermidis present on the blood agar which was
streaked with a 0.001 loop. What should the tech do next?
A. Reject culture due to contamination
B. Perform sensitivity on S. epidermidis
C. Report culture as no growth
D. List S. epidermidis as a possible contaminant - ANSWER D
,5. Small, transparent, gray-yellow 48 hour colonies incubated at 37°C are
surrounded by wide zones of beta hemolysis. This culture was obtained from a
throat swab of a patient with pharyngitis. The isolate is susceptible to the
bacitracin "A" disc. What is the presumptive identification of this isolate?
A. Streptococcus pyogenes (Group A)
B. Streptococcus agalactiae (Group B)
C. Streptococcus pneumoniae
D. Streptococcus anginosus (Group F) - ANSWER A
6. Which of the following Enterobacteriaceae produces H2S?
A. Klebsiella species
B. Escherichia species
C. Salmonella species
D. Yersinia species - ANSWER C
7. Sulfonamides, such as sulfamethoxazole (SMZ), and trimethoprim (TMP), work
by targeting:
A. Penicillin-binding proteins; disrupting bacterial cell wall synthesis
B. Tetrahydrofolate synthesis; preventing bacterial DNA synthesis
C. 30S ribosomal subunits; inhibiting bacterial protein translation
D. 50S ribosomal subunits; inhibiting bacterial protein translation - ANSWER B
8. In patients who present with a classic "strep throat", the beta-hemolytic,
catalase negative, Gram positive bacillus that must be included in the
differential diagnosis is:
A. Actinomyces species
B. Arcanobacterium haemolyticum
C. Listeria monocytogenes
D. Gardnerella vaginalis - ANSWER B
9. Which of the following serological tests would be used for the diagnosis of Q-
fever?
A. Weil-Felix test
B. Quellung test
C. EIA or indirect immunoflourescence
D. Cold agglutinin test - ANSWER C
10. On MacConkey (MAC) agar, an isolate from a stool sample produced clear,
colorless colonies. On Hektoen enteric (HE) agar, colonies were green with
black centers, indicative of H2S production. Additional biochemical tests were
,positive for methyl red, and negative for indole, VP, citrate, and PAD. From the
choices listed, which species best matches the characteristics described?
A. Salmonella Typhi
B. Proteus mirabilis
C. Shigella sonnei
D. Escherichia coli - ANSWER A
11. In an urinalysis, tests are performed that serve as a method of screening for
urinary tract infections. Which of following tests detects the presence of
inflammatory cells?
A. Niacin test
B. Nitrate reduction test
C. Leukocyte esterase test
D. Catalase test - ANSWER C
12. A microbiology laboratory recently purchased a rapid identification
instrument that uses a laser on the microorganisms, which produces an ion
cloud. These ions are then separated in a tube and travel within the tube to a
detector. The time of travel will be measured and a mass spectrum will be
produced. Which of the following techniques uses this methodology?
A. API 20E
B. Vitek
C. Microscan
D. MALDI-TOF - ANSWER D
13. Which of the following is oxidase positive?
A. Pseudomonas aeruginosa
B. Serratia marscescens
C. Edwardsiella tarda
D. Providencia rettgeri - ANSWER A
14. An Enterobacteriaceae grows as a clear colony on MacConkey but a salmon-
colored colony with a black center on Hektoen enteric agar. Which of the
following TSI reactions would match these morphologies?
A. Alk/A H2S
B. A/A H2S
C. Alk/A no H2S
D. A/A no H2S - ANSWER B
15. What is the role of a sentinel laboratory within the Laboratory Response
Network (LRN)?
, A. Performs tests to detect and confirm or "rule-in" the presence of a threat
agent
B. Use standardized testing protocols to rule-out critical biological agents or
refer them to one of the LRN reference laboratories for identification
C. Act as the highest level in the LRN to handle highly infectious agents and have
the ability to identify specific agent strains
D. Development of new diagnostic tests for identification of potential bioterror
agents - ANSWER B
16. Specimen handling from patients with symptoms consistent with tularemia
requires work in a biological safety cabinet. Although PCR may confirm infection
with Francisella tularensis, the following culture characteristics and tests aid in
presumptive identification:
A. Slow growth on MAC, fast growth on CHOC; oxidase positive, negative
catalase, X and V factor requirement positive
B. No growth on MAC, slow growth on CHOC; oxidase negative, positive
catalase and ß-lactamase
C. Fast growth on SBA and MAC; oxidase, catalase, and urease positive
D. Slow growth on MAC and EMB; oxidase, catalase, and urease negative -
ANSWER B
17. A CSF specimen was sent to the laboratory for analysis. A glucose, protein,
and cell count were performed. Based on the following results, what would be
the probable cause?
Glucose - 50 mg/dL
Protein - 25 mg/dL
Leukocytes - 2 cells/mm^3
A. Normal CSF
B. Viral infection
C. Purulent infection
D. Tuberculosis or fungi infection - ANSWER A
18. Many organisms have developed resistance to antibiotics. What mode of
resistance has MRSA acquired?
A. Acquisition of new targets
B. Enzymatic inactivation of antibiotics
C. Efflux
D. Target site modification - ANSWER A
19. Eikenella corrodens is associated with which of the following?
Bacteriology Exam Study Guide
1. A Staphylococcus species recovered from a CSF shunt culture was found to
produce acid from sucrose and maltose and showed alkaline phosphatase
activity. The Staphylococcus was also coagulase negative. The most likely
identification is:
A. Staphylococcus epidermidis
B. Staphylococcus aureus
C. Staphylococcus schleiferi
D. Staphylococcus saprophyticus - ANSWER A
2. Isolates of nonmotile and nonpigmented enterococci that are resistant to
vancomycin can be assumed to have an acquired resistance by the transfer of
which of the following genes?
A. van A and van C genes
B. van B and van C genes
C. van A and van B genes
D. mec A and van C genes - ANSWER C
3. Some strains of Group F Strep can carry the group A antigen, potentially
leading to a false positive identification of group A, Streptococcus pyogenes. A
spot test that is helpful in differentiating these two species and thus preventing a
false report is:
A. Catalase
B. Bile solubility
C. Pyrrolidonyl-b-naphthylamide (PYR)
D. Cytochrome oxidase - ANSWER C
4. A tech is interpreting a urine culture from a catheter as the source. There is 1
colony of Staphylococcus epidermidis present on the blood agar which was
streaked with a 0.001 loop. What should the tech do next?
A. Reject culture due to contamination
B. Perform sensitivity on S. epidermidis
C. Report culture as no growth
D. List S. epidermidis as a possible contaminant - ANSWER D
,5. Small, transparent, gray-yellow 48 hour colonies incubated at 37°C are
surrounded by wide zones of beta hemolysis. This culture was obtained from a
throat swab of a patient with pharyngitis. The isolate is susceptible to the
bacitracin "A" disc. What is the presumptive identification of this isolate?
A. Streptococcus pyogenes (Group A)
B. Streptococcus agalactiae (Group B)
C. Streptococcus pneumoniae
D. Streptococcus anginosus (Group F) - ANSWER A
6. Which of the following Enterobacteriaceae produces H2S?
A. Klebsiella species
B. Escherichia species
C. Salmonella species
D. Yersinia species - ANSWER C
7. Sulfonamides, such as sulfamethoxazole (SMZ), and trimethoprim (TMP), work
by targeting:
A. Penicillin-binding proteins; disrupting bacterial cell wall synthesis
B. Tetrahydrofolate synthesis; preventing bacterial DNA synthesis
C. 30S ribosomal subunits; inhibiting bacterial protein translation
D. 50S ribosomal subunits; inhibiting bacterial protein translation - ANSWER B
8. In patients who present with a classic "strep throat", the beta-hemolytic,
catalase negative, Gram positive bacillus that must be included in the
differential diagnosis is:
A. Actinomyces species
B. Arcanobacterium haemolyticum
C. Listeria monocytogenes
D. Gardnerella vaginalis - ANSWER B
9. Which of the following serological tests would be used for the diagnosis of Q-
fever?
A. Weil-Felix test
B. Quellung test
C. EIA or indirect immunoflourescence
D. Cold agglutinin test - ANSWER C
10. On MacConkey (MAC) agar, an isolate from a stool sample produced clear,
colorless colonies. On Hektoen enteric (HE) agar, colonies were green with
black centers, indicative of H2S production. Additional biochemical tests were
,positive for methyl red, and negative for indole, VP, citrate, and PAD. From the
choices listed, which species best matches the characteristics described?
A. Salmonella Typhi
B. Proteus mirabilis
C. Shigella sonnei
D. Escherichia coli - ANSWER A
11. In an urinalysis, tests are performed that serve as a method of screening for
urinary tract infections. Which of following tests detects the presence of
inflammatory cells?
A. Niacin test
B. Nitrate reduction test
C. Leukocyte esterase test
D. Catalase test - ANSWER C
12. A microbiology laboratory recently purchased a rapid identification
instrument that uses a laser on the microorganisms, which produces an ion
cloud. These ions are then separated in a tube and travel within the tube to a
detector. The time of travel will be measured and a mass spectrum will be
produced. Which of the following techniques uses this methodology?
A. API 20E
B. Vitek
C. Microscan
D. MALDI-TOF - ANSWER D
13. Which of the following is oxidase positive?
A. Pseudomonas aeruginosa
B. Serratia marscescens
C. Edwardsiella tarda
D. Providencia rettgeri - ANSWER A
14. An Enterobacteriaceae grows as a clear colony on MacConkey but a salmon-
colored colony with a black center on Hektoen enteric agar. Which of the
following TSI reactions would match these morphologies?
A. Alk/A H2S
B. A/A H2S
C. Alk/A no H2S
D. A/A no H2S - ANSWER B
15. What is the role of a sentinel laboratory within the Laboratory Response
Network (LRN)?
, A. Performs tests to detect and confirm or "rule-in" the presence of a threat
agent
B. Use standardized testing protocols to rule-out critical biological agents or
refer them to one of the LRN reference laboratories for identification
C. Act as the highest level in the LRN to handle highly infectious agents and have
the ability to identify specific agent strains
D. Development of new diagnostic tests for identification of potential bioterror
agents - ANSWER B
16. Specimen handling from patients with symptoms consistent with tularemia
requires work in a biological safety cabinet. Although PCR may confirm infection
with Francisella tularensis, the following culture characteristics and tests aid in
presumptive identification:
A. Slow growth on MAC, fast growth on CHOC; oxidase positive, negative
catalase, X and V factor requirement positive
B. No growth on MAC, slow growth on CHOC; oxidase negative, positive
catalase and ß-lactamase
C. Fast growth on SBA and MAC; oxidase, catalase, and urease positive
D. Slow growth on MAC and EMB; oxidase, catalase, and urease negative -
ANSWER B
17. A CSF specimen was sent to the laboratory for analysis. A glucose, protein,
and cell count were performed. Based on the following results, what would be
the probable cause?
Glucose - 50 mg/dL
Protein - 25 mg/dL
Leukocytes - 2 cells/mm^3
A. Normal CSF
B. Viral infection
C. Purulent infection
D. Tuberculosis or fungi infection - ANSWER A
18. Many organisms have developed resistance to antibiotics. What mode of
resistance has MRSA acquired?
A. Acquisition of new targets
B. Enzymatic inactivation of antibiotics
C. Efflux
D. Target site modification - ANSWER A
19. Eikenella corrodens is associated with which of the following?
