Selecting oral Treponema species When attempting to select Treponema species from the human oral cavity, which practical criteria can be used to enrich and recognize these spirochetes during laboratory work?

Introduction / Context:
Treonemes in the oral cavity are delicate, thin spirochetes that can be difficult to culture. When recovery is required for research or advanced diagnostics, laboratories combine environmental controls, microscopic screening, and tailored media to enrich treponemes from polymicrobial oral specimens.

Given Data / Assumptions:

• Treponema are slender, highly motile spirochetes.
• They prefer near-neutral pH, reduced oxygen tension, and specific temperatures.
• Dark-field microscopy allows rapid recognition by size and motility.

Concept / Approach:
Enrichment of oral Treponema typically includes microaerophilic or anaerobic incubation and temperature near human physiological range, together with media components that do not suppress spirochetes. Screening by dark-field detects their distinctive corkscrew motility and small diameter compared with commensal rods and cocci. pH adjustment, while not extreme, supports viability and can suppress some competitors.

Step-by-Step Solution:
Control pH to conditions compatible with treponemal survival (near neutral, avoiding extremes).Incubate at appropriate temperature (about 35–37 °C) under microaerophilic/anaerobic conditions.Use dark-field to identify thin, actively motile spirochetes by size and movement pattern.Combine these measures to enrich and select oral Treponema from mixed flora.

Verification / Alternative check:
Classic periodontal research protocols employ microaerophilic chambers and dark-field motility counts to track Treponema abundance.

Why Other Options Are Wrong:

• A/B/C individually help, but optimal recovery uses the combination; hence “All of these.”
• E is incorrect because each listed factor can contribute to selection.

Common Pitfalls:
Over-oxidizing environments or using routine aerobic incubation will kill or severely reduce treponemes, leading to false-negative results.

Final Answer:
All of these