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 (Foundations &
Koch’s postulates)
Stem: A patient develops a wound infection after a dog bite. A
microbiology student isolates the same Gram-negative bacillus
from the wound and from the wound fluid in pure culture;
inoculation of a healthy mouse with the isolate produces a
similar lesion. Recovery of the same organism from the
experimentally infected mouse is confirmed. Which conclusion
,is most supported?
A. The isolated organism is a normal skin commensal.
B. The organism is the likely etiologic agent of the wound
infection.
C. The infection is caused by a viral co-pathogen not detected
by culture.
D. The isolate is a laboratory contaminant and unrelated to
disease.
Correct answer: B
Rationale — Correct (B): The described sequence fulfills Koch’s
postulates (isolation from disease, pure culture, reproduction of
disease in a susceptible host, and re-isolation), supporting
causation by the isolated organism. This provides strong
experimental evidence that the bacterium is the etiologic agent.
Rationale — Incorrect (A): A commensal would not reliably
reproduce the same disease in an animal model.
Rationale — Incorrect (C): No data supports a viral co-
pathogen; culture and disease reproduction implicate the
bacterium.
Rationale — Incorrect (D): A contaminant would be unlikely to
reproduce identical disease in an animal and be consistently re-
isolated.
Teaching point: Koch’s postulates link isolation and disease
reproduction to identify etiologic agents.
Citation: Bartolome, F. A., & Quiles, E. P. (Year). Microbiology
and Parasitology. 2nd Ed., Ch. 1.
,2.
Reference: Ch. 1 — The Science of Microbiology (Microbial
diversity & taxonomy)
Stem: A clinician receives a lab report naming an organism by a
three-part designation (genus, species, subspecies). The
clinician asks why scientific names are used instead of common
names. Which is the best explanation for the preference for
binomial nomenclature in clinical microbiology?
A. Common names are banned by international law in lab
reports.
B. Binomial names standardize identification and reduce
ambiguity across languages and regions.
C. Common names always refer to viruses, so they are unusable
for bacteria.
D. Binomial names are easier to pronounce for clinicians.
Correct answer: B
Rationale — Correct (B): Binomial nomenclature (genus and
species; sometimes subspecies) provides a universal,
standardized naming system that reduces ambiguity and
enables precise communication in clinical and public-health
contexts.
Rationale — Incorrect (A): There is no legal ban on common
names; the issue is precision and standardization.
Rationale — Incorrect (C): Common names can refer to any
microbe; the problem is ambiguity, not organism type.
, Rationale — Incorrect (D): Pronounceability is irrelevant; the
system’s value is unambiguous identification.
Teaching point: Scientific names provide universal,
unambiguous organism identification.
Citation: Bartolome, F. A., & Quiles, E. P. (Year). Microbiology
and Parasitology. 2nd Ed., Ch. 1.
3.
Reference: Ch. 1 — The Science of Microbiology (Microscopy &
resolution)
Stem: A lab technologist must visualize intracellular bacteria in
a fresh sputum smear. Bright-field light microscopy with a 100×
oil-immersion objective yields poor detail. Which microscopic
technique will best improve resolution to reveal small
intracellular bacteria?
A. Phase-contrast microscopy without staining.
B. Electron microscopy (transmission).
C. Fluorescence microscopy using DAPI.
D. Simple light microscopy at 40× objective.
Correct answer: B
Rationale — Correct (B): Transmission electron microscopy
provides much higher resolution (nanometer scale) than light
microscopy and can visualize ultrastructural details of small
intracellular bacteria. It’s the appropriate choice when light
microscopy lacks resolving power.