Susceptibility profile of bacteria obtained from human oro-dental plaques at the dental clinic of the University of Benin Teaching Hospital, Benin City, Nigeria

Background: The oral cavity harbours a diverse community of anaerobic bacterial; many of which have been implicated in life threatening oro-dental and systemic infections.

Objectives: This study evaluated the antimicrobial susceptibility profile of aerobic and anaerobic bacterial isolates obtained from plaque scrapings in patients who visited the study center for scaling and polishing.

Methods: Plaques were scraped from the tooth surface of each study participants with the aid of a sterile tweezer; into specimen collection bottles containing 5mL of sodium thioglycolate broth. This was transported within 2 hours to the laboratory and then subcultured into appropriate growth media for aerobic and anaerobic incubation. Anaerobiosis was achieved by chemical method (pyrrogalor crystals+ NaOH solution). Gram staining and biochemical tests were used to identify resultant bacterial colonies. Susceptibility profile of bacteria isolates were determined by agar disc diffusion assay.

Results: In order of distribution, Streptococcus spp., had the highest frequency of occurrence (42%), followed by Prevotella spp which accounted for (34%). Staphylococcus and Clostridium spps. were least frequently encountered accounting for 15 and 9 % respectively. Susceptibility test result showed that the perfloxacin had high antimicrobial activity, while erythromycin, aminoglycosides and cefotaxim were moderately effective against bacterial isolates. However, amoxicillin and cotrimoxazole showed less activity.

Conclusion: Continuous surveillance studies on the antimicrobial susceptibility profiles of plaque associated bacteria is crucial in identifying emerging resistance patterns. This data can guide healthcare providers in adapting treatment strategies and developing new therapeutic approaches in the management of oro-dental infections.