TEXTBOOK OF DIAGNOSTIC
MICROBIOLOGY SIXTH EDITION CONNIE R
MAHON VERIFIED CHAPTERS ONE
THROUGH FORTY ONE COMPLETE
QUESTIONS AND ANSWERS GRADED A+
⩥ List the major steps in the diagnostic microbiology cycle.
Answer: Clinical sample and history; sample transport; laboratory
analysis; interpretation and use of the information.
⩥ Why is collection of the correct clinical sample considered the critical
first step?
Answer: Because accurate organism identification depends on getting
the right specimen from the right site, collected properly and with the
right clinical history.
⩥ What clinical information should accompany a microbiology
specimen request?
Answer: Type and site of sample, suspected diagnosis, patient age,
overall health, prior antibiotic use, medications, and allergies.
⩥ Why should samples ideally be taken before antibiotics are started?
,Answer: Antibiotics can alter the quantity and viability of microbes,
leading to misleading or false-negative results.
⩥ What risk can delayed transport create for hardy organisms in a
specimen?
Answer: They may overgrow at room temperature and distort the true
microbiologic picture.
⩥ Why must specimen transport containers be appropriate and safe?
Answer: To preserve organism viability, prevent contamination, and
protect personnel from exposure.
⩥ What special transport condition is required for anaerobic organisms?
Answer: They must be transported in proper anaerobic containers to
prevent oxygen exposure.
⩥ Freshly collected specimens are preferred because why?
Answer: Microbial viability changes over time, and delays can reduce
recovery or alter quantitative results.
⩥ How should a purulent oral infection specimen be collected?
Answer: By needle aspiration of pus, followed by obligatory drainage.
⩥ How is a sample commonly collected for oral Candida on mucosa?
, Answer: With a dry swab from the affected mucosal surface.
⩥ What collection method can be used to quantify oral yeast growth?
Answer: An oral saline rinse transferred into a sterile tube.
⩥ What type of sample is useful for acute necrotizing ulcerative
gingivitis?
Answer: Deep gingival smears.
⩥ What type of sample is useful for DNA analysis of periodontopathic
bacteria?
Answer: Paper point samples.
⩥ Why may paper point DNA results in periodontal disease be
nonconclusive?
Answer: Because detecting bacterial DNA does not always prove active
disease or organism viability.
⩥ In dental caries, which organisms are commonly counted in saliva?
Answer: Lactobacilli and Streptococcus mutans.
⩥ For suspected thrush (Candida albicans), what sample is often sent to
the lab according to the notes?
MICROBIOLOGY SIXTH EDITION CONNIE R
MAHON VERIFIED CHAPTERS ONE
THROUGH FORTY ONE COMPLETE
QUESTIONS AND ANSWERS GRADED A+
⩥ List the major steps in the diagnostic microbiology cycle.
Answer: Clinical sample and history; sample transport; laboratory
analysis; interpretation and use of the information.
⩥ Why is collection of the correct clinical sample considered the critical
first step?
Answer: Because accurate organism identification depends on getting
the right specimen from the right site, collected properly and with the
right clinical history.
⩥ What clinical information should accompany a microbiology
specimen request?
Answer: Type and site of sample, suspected diagnosis, patient age,
overall health, prior antibiotic use, medications, and allergies.
⩥ Why should samples ideally be taken before antibiotics are started?
,Answer: Antibiotics can alter the quantity and viability of microbes,
leading to misleading or false-negative results.
⩥ What risk can delayed transport create for hardy organisms in a
specimen?
Answer: They may overgrow at room temperature and distort the true
microbiologic picture.
⩥ Why must specimen transport containers be appropriate and safe?
Answer: To preserve organism viability, prevent contamination, and
protect personnel from exposure.
⩥ What special transport condition is required for anaerobic organisms?
Answer: They must be transported in proper anaerobic containers to
prevent oxygen exposure.
⩥ Freshly collected specimens are preferred because why?
Answer: Microbial viability changes over time, and delays can reduce
recovery or alter quantitative results.
⩥ How should a purulent oral infection specimen be collected?
Answer: By needle aspiration of pus, followed by obligatory drainage.
⩥ How is a sample commonly collected for oral Candida on mucosa?
, Answer: With a dry swab from the affected mucosal surface.
⩥ What collection method can be used to quantify oral yeast growth?
Answer: An oral saline rinse transferred into a sterile tube.
⩥ What type of sample is useful for acute necrotizing ulcerative
gingivitis?
Answer: Deep gingival smears.
⩥ What type of sample is useful for DNA analysis of periodontopathic
bacteria?
Answer: Paper point samples.
⩥ Why may paper point DNA results in periodontal disease be
nonconclusive?
Answer: Because detecting bacterial DNA does not always prove active
disease or organism viability.
⩥ In dental caries, which organisms are commonly counted in saliva?
Answer: Lactobacilli and Streptococcus mutans.
⩥ For suspected thrush (Candida albicans), what sample is often sent to
the lab according to the notes?
