Shift in Oral Commensals During A 5-Day Metronidazole Therapy
Abstract
Fathilah AR, Zakir MH, Bakri MM, Ab-Murat N and Ramanathan A
Background: Antibiotic treatment induces great ecological impact on normal flora of the human body. Suppression of growth on these commensal microorganisms may give rise to opportunistic infection especially to those who are immuno-compromised. In the mouth, oral thrush represents a common indication of an opportunistic infection by fungus of the genus Candida. This study aimed to assess the effect of a 5-day metronidazole therapy on oral microbes to enable evaluation of its influence on the candidal, streptococci and other bacterial inhabitants of the oral cavity.
Methods: Tongue scrape specimens from ten patients who were due for minor oral surgery were collected and processed using conventional microbiological procedures involving spreading of specimens on selective agar plates. The specimens were collected on the first, second and a day after the 5-day metronidazole therapy.
Results: Distribution of oral candida, streptococci and other bacterial inhabitants experienced changes over the duration of treatment. An increased candidal population from 34.2% before to 45.3% during, and a contrasting decreased in streptococcal presence from 41% before to 28% during the therapy were observed. Similar trend of reduction was obtained on other bacteria from 37% before to 24% over the antibiotic therapy. The influence of metronidazole seem to slowly diminish upon completion of the 5-day therapy as all three microbial groups adapt to regain the original distribution pattern.
Conclusion: The course of a 5-day metronidazole treatment affected microbial balance of the oral residents that lead to a significant rise of opportunistic species to take advantage of the disturbed ecological balance.