MICROBIOLOGY AND PARASITOLOGY: A
TEXTBOOK AND LABORATORY MANUAL
FOR THE HEALTH SCIENCES
2ND EDITION
• AUTHOR(S)FE A. BARTOLOME, AND
ELIZABETH P. QUILES
TEST BANK
1
Reference
Ch. 1 — The Science of Microbiology
Stem
A 55-year-old patient develops sudden fever and purulent
wound drainage after abdominal surgery. The on-call clinician
suspects a postoperative infection and requests wound swabs.
The lab reports many polymorphonuclear leukocytes on direct
,Gram-stained smear and mixed moderate growth of skin-
colonizing organisms from the swab culture. Which
interpretation best guides the clinician about the likely cause
and next step?
Options
A. The Gram smear and culture indicate a deep surgical-site
infection by a single pathogen; start broad-spectrum IV
antibiotics immediately.
B. The Gram smear suggests inflammation, but mixed growth
from a swab likely reflects contamination; obtain a deep tissue
aspirate for culture.
C. Mixed growth means polymicrobial infection from the
operating room; no further sampling is necessary—treat with
topical antiseptic.
D. Presence of PMNs on smear rules out contamination; treat
empirically for Staphylococcus aureus only.
Correct answer
B
Rationales
Correct (B): A Gram-stained smear showing many PMNs
indicates true inflammation/infection, but swab cultures
frequently yield mixed skin flora due to contamination. For
accurate pathogen identification in suspected deep surgical-site
infection, a properly collected deep tissue sample or aspirate is
required before targeted therapy.
A: Incorrect — a swab with mixed growth does not reliably
,identify a single deep-tissue pathogen; immediate broad-
spectrum IV therapy may be premature without proper
specimen.
C: Incorrect — mixed culture from a superficial swab is more
consistent with contamination than definitive polymicrobial
operative contamination; topical antiseptic alone is inadequate
for likely deep infection.
D: Incorrect — PMNs show host response but do not identify a
single organism; assuming S. aureus risks inappropriate therapy.
Teaching point
Superficial swabs often contaminate; deep aspirates/tissue
samples improve diagnostic accuracy.
Citation
Bartolome, F. A., & Quiles, E. P. (Year). Microbiology and
Parasitology. 2nd Ed., Ch. 1.
2
Reference
Ch. 1 — The Science of Microbiology
Stem
A hospital microbiology lab is revising its biosafety practices. A
new bench procedure involves handling large volumes of non-
sterile environmental water suspected to contain Legionella.
Which biosafety level (BSL) and containment practice is most
, appropriate for routine culture and manipulation of this
environmental sample?
Options
A. BSL-1 with standard microbiological practices and open
bench work.
B. BSL-2 with enhanced PPE and biological safety cabinet (Class
II) for manipulations that can generate aerosols.
C. BSL-3 with negative-pressure rooms and full respiratory
protection for all culture plates.
D. BSL-4 with full-body positive-pressure suits due to unknown
environmental organisms.
Correct answer
B
Rationales
Correct (B): Legionella and many environmental opportunists
are handled at BSL-2; procedures that may create aerosols
(concentration, vortexing) require a Class II biosafety cabinet
and appropriate PPE. BSL-2 balances risk mitigation and
practicality for such organisms.
A: Incorrect — BSL-1 is for well-characterized agents not known
to cause disease in healthy adults; environmental water with
Legionella risk exceeds BSL-1.
C: Incorrect — BSL-3 is for agents with respiratory transmission
and higher virulence (e.g., Mycobacterium tuberculosis); not
routinely required for environmental Legionella work.
D: Incorrect — BSL-4 is reserved for high-risk, life-threatening
TEXTBOOK AND LABORATORY MANUAL
FOR THE HEALTH SCIENCES
2ND EDITION
• AUTHOR(S)FE A. BARTOLOME, AND
ELIZABETH P. QUILES
TEST BANK
1
Reference
Ch. 1 — The Science of Microbiology
Stem
A 55-year-old patient develops sudden fever and purulent
wound drainage after abdominal surgery. The on-call clinician
suspects a postoperative infection and requests wound swabs.
The lab reports many polymorphonuclear leukocytes on direct
,Gram-stained smear and mixed moderate growth of skin-
colonizing organisms from the swab culture. Which
interpretation best guides the clinician about the likely cause
and next step?
Options
A. The Gram smear and culture indicate a deep surgical-site
infection by a single pathogen; start broad-spectrum IV
antibiotics immediately.
B. The Gram smear suggests inflammation, but mixed growth
from a swab likely reflects contamination; obtain a deep tissue
aspirate for culture.
C. Mixed growth means polymicrobial infection from the
operating room; no further sampling is necessary—treat with
topical antiseptic.
D. Presence of PMNs on smear rules out contamination; treat
empirically for Staphylococcus aureus only.
Correct answer
B
Rationales
Correct (B): A Gram-stained smear showing many PMNs
indicates true inflammation/infection, but swab cultures
frequently yield mixed skin flora due to contamination. For
accurate pathogen identification in suspected deep surgical-site
infection, a properly collected deep tissue sample or aspirate is
required before targeted therapy.
A: Incorrect — a swab with mixed growth does not reliably
,identify a single deep-tissue pathogen; immediate broad-
spectrum IV therapy may be premature without proper
specimen.
C: Incorrect — mixed culture from a superficial swab is more
consistent with contamination than definitive polymicrobial
operative contamination; topical antiseptic alone is inadequate
for likely deep infection.
D: Incorrect — PMNs show host response but do not identify a
single organism; assuming S. aureus risks inappropriate therapy.
Teaching point
Superficial swabs often contaminate; deep aspirates/tissue
samples improve diagnostic accuracy.
Citation
Bartolome, F. A., & Quiles, E. P. (Year). Microbiology and
Parasitology. 2nd Ed., Ch. 1.
2
Reference
Ch. 1 — The Science of Microbiology
Stem
A hospital microbiology lab is revising its biosafety practices. A
new bench procedure involves handling large volumes of non-
sterile environmental water suspected to contain Legionella.
Which biosafety level (BSL) and containment practice is most
, appropriate for routine culture and manipulation of this
environmental sample?
Options
A. BSL-1 with standard microbiological practices and open
bench work.
B. BSL-2 with enhanced PPE and biological safety cabinet (Class
II) for manipulations that can generate aerosols.
C. BSL-3 with negative-pressure rooms and full respiratory
protection for all culture plates.
D. BSL-4 with full-body positive-pressure suits due to unknown
environmental organisms.
Correct answer
B
Rationales
Correct (B): Legionella and many environmental opportunists
are handled at BSL-2; procedures that may create aerosols
(concentration, vortexing) require a Class II biosafety cabinet
and appropriate PPE. BSL-2 balances risk mitigation and
practicality for such organisms.
A: Incorrect — BSL-1 is for well-characterized agents not known
to cause disease in healthy adults; environmental water with
Legionella risk exceeds BSL-1.
C: Incorrect — BSL-3 is for agents with respiratory transmission
and higher virulence (e.g., Mycobacterium tuberculosis); not
routinely required for environmental Legionella work.
D: Incorrect — BSL-4 is reserved for high-risk, life-threatening
