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
Q1
Reference: Ch. 1 — The Science of Microbiology
Stem: A newly admitted patient has fever and an indwelling
urinary catheter. The laboratory receives a midstream urine
specimen and notes abundant neutrophils on wet mount but
scant bacterial growth on standard aerobic culture after 24
hours. Which laboratory explanation best fits these findings?
A. The infection is viral and therefore will not grow on bacterial
culture.
,B. The specimen contains fastidious bacteria requiring enriched
or special media.
C. The specimen was contaminated with epithelial cells, diluting
the pathogen.
D. The culture incubation time was excessive and killed the
bacteria.
Correct answer: B
Rationale — Correct (B): Fastidious bacteria (e.g., Haemophilus,
Gardnerella-like organisms) may appear in inflammatory urine
but fail to grow on routine media; enriched/special media or
prolonged incubation is required. The presence of neutrophils
indicates host response consistent with bacterial infection, not
viral. Recognizing growth requirements informs appropriate
culture requests.
Rationale — A: Viral urinary infections are uncommon and
would not produce neutrophil-rich urine; viruses also typically
require different detection methods, not routine bacterial
culture.
Rationale — C: Contamination with epithelial cells usually
indicates poor collection but would not explain neutrophil
predominance plus low culture yield.
Rationale — D: Excessive incubation does not kill bacteria;
short incubation might miss slow growers, not prolonged
incubation.
Teaching point: Fastidious organisms need special media or
prolonged incubation for detection.
,Citation: Bartolome, F. A., & Quiles, E. P. (Year). Microbiology
and Parasitology. 2nd Ed., Ch. 1.
Q2
Reference: Ch. 1 — The Science of Microbiology
Stem: A public health team is investigating an outbreak; they
must demonstrate a particular microbe causes disease. Which
approach best satisfies Koch’s postulates in this real-world
setting?
A. Detect microbe DNA in patient samples using PCR alone.
B. Isolate the organism in pure culture and reproduce disease in
a suitable model.
C. Observe the organism microscopically in patient tissues
without isolation.
D. Show that patients share a common exposure history via
epidemiologic curve.
Correct answer: B
Rationale — Correct (B): Koch’s postulates require consistent
association, isolation in pure culture, and reproduction of
disease in a susceptible host; isolation plus disease
reproduction provides strong causality evidence. Modern
adaptations accept molecular substitutes when models are
impractical, but classical demonstration remains gold standard.
Rationale — A: PCR detection shows association but cannot
prove causation alone, as DNA may persist without active
disease.
, Rationale — C: Microscopic observation supports association
but lacks proof of causality without isolation and reproduction.
Rationale — D: Exposure histories support epidemiologic links
but do not prove a specific organism causes disease.
Teaching point: Koch’s postulates emphasize isolation and
reproduction of disease for causation.
Citation: Bartolome, F. A., & Quiles, E. P. (Year). Microbiology
and Parasitology. 2nd Ed., Ch. 1.
Q3
Reference: Ch. 1 — The Science of Microbiology
Stem: A lab student must choose which microscope objective to
use when identifying bacterial morphology in a Gram-stained
slide. The teacher expects clear resolution of cocci in clusters.
Which objective and technique are appropriate?
A. 40× objective alone, with brightfield illumination.
B. 100× oil-immersion objective with immersion oil and
brightfield.
C. 10× objective with phase-contrast illumination.
D. 4× scanning objective and darkfield illumination.
Correct answer: B
Rationale — Correct (B): Bacterial morphology (size and
arrangement) requires high magnification and numerical
aperture; the 100× oil-immersion objective with oil increases
resolution for Gram-stained bacteria in brightfield. Proper oil
contact and focusing technique are essential.
TEXTBOOK AND LABORATORY MANUAL
FOR THE HEALTH SCIENCES
2ND EDITION
• AUTHOR(S)FE A. BARTOLOME, AND
ELIZABETH P. QUILES
TEST BANK
Q1
Reference: Ch. 1 — The Science of Microbiology
Stem: A newly admitted patient has fever and an indwelling
urinary catheter. The laboratory receives a midstream urine
specimen and notes abundant neutrophils on wet mount but
scant bacterial growth on standard aerobic culture after 24
hours. Which laboratory explanation best fits these findings?
A. The infection is viral and therefore will not grow on bacterial
culture.
,B. The specimen contains fastidious bacteria requiring enriched
or special media.
C. The specimen was contaminated with epithelial cells, diluting
the pathogen.
D. The culture incubation time was excessive and killed the
bacteria.
Correct answer: B
Rationale — Correct (B): Fastidious bacteria (e.g., Haemophilus,
Gardnerella-like organisms) may appear in inflammatory urine
but fail to grow on routine media; enriched/special media or
prolonged incubation is required. The presence of neutrophils
indicates host response consistent with bacterial infection, not
viral. Recognizing growth requirements informs appropriate
culture requests.
Rationale — A: Viral urinary infections are uncommon and
would not produce neutrophil-rich urine; viruses also typically
require different detection methods, not routine bacterial
culture.
Rationale — C: Contamination with epithelial cells usually
indicates poor collection but would not explain neutrophil
predominance plus low culture yield.
Rationale — D: Excessive incubation does not kill bacteria;
short incubation might miss slow growers, not prolonged
incubation.
Teaching point: Fastidious organisms need special media or
prolonged incubation for detection.
,Citation: Bartolome, F. A., & Quiles, E. P. (Year). Microbiology
and Parasitology. 2nd Ed., Ch. 1.
Q2
Reference: Ch. 1 — The Science of Microbiology
Stem: A public health team is investigating an outbreak; they
must demonstrate a particular microbe causes disease. Which
approach best satisfies Koch’s postulates in this real-world
setting?
A. Detect microbe DNA in patient samples using PCR alone.
B. Isolate the organism in pure culture and reproduce disease in
a suitable model.
C. Observe the organism microscopically in patient tissues
without isolation.
D. Show that patients share a common exposure history via
epidemiologic curve.
Correct answer: B
Rationale — Correct (B): Koch’s postulates require consistent
association, isolation in pure culture, and reproduction of
disease in a susceptible host; isolation plus disease
reproduction provides strong causality evidence. Modern
adaptations accept molecular substitutes when models are
impractical, but classical demonstration remains gold standard.
Rationale — A: PCR detection shows association but cannot
prove causation alone, as DNA may persist without active
disease.
, Rationale — C: Microscopic observation supports association
but lacks proof of causality without isolation and reproduction.
Rationale — D: Exposure histories support epidemiologic links
but do not prove a specific organism causes disease.
Teaching point: Koch’s postulates emphasize isolation and
reproduction of disease for causation.
Citation: Bartolome, F. A., & Quiles, E. P. (Year). Microbiology
and Parasitology. 2nd Ed., Ch. 1.
Q3
Reference: Ch. 1 — The Science of Microbiology
Stem: A lab student must choose which microscope objective to
use when identifying bacterial morphology in a Gram-stained
slide. The teacher expects clear resolution of cocci in clusters.
Which objective and technique are appropriate?
A. 40× objective alone, with brightfield illumination.
B. 100× oil-immersion objective with immersion oil and
brightfield.
C. 10× objective with phase-contrast illumination.
D. 4× scanning objective and darkfield illumination.
Correct answer: B
Rationale — Correct (B): Bacterial morphology (size and
arrangement) requires high magnification and numerical
aperture; the 100× oil-immersion objective with oil increases
resolution for Gram-stained bacteria in brightfield. Proper oil
contact and focusing technique are essential.
