Metronidazole is added to doxycycline in some outpatient regimens for pelvic inflammatory disease. The principal additional coverage provided by metronidazole in this setting is against:
- A Anaerobes such as Bacteroides species ✓
- B Chlamydia trachomatis
- C Mycoplasma genitalium
- D Trichomonas vaginalis in the lower tract only
Correct answer: A. Anaerobes such as Bacteroides species
Explanation
PID is polymicrobial, and anaerobes of the Bacteroides group contribute to tubo-ovarian abscess formation. Metronidazole provides anaerobic coverage that doxycycline lacks, reducing abscess risk. Doxycycline already covers chlamydia, and neither agent reliably treats Mycoplasma genitalium, which needs azithromycin or moxifloxacin. Although metronidazole treats trichomoniasis, that is incidental here and not the rationale for its inclusion in PID therapy.
Reference: CDC STI Treatment Guidelines, 2021 ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.