Bacteriologic features and antimicrobial resistance of organisms associated with extracted teeth: findings from a Nigerian university teaching hospital

Abstract

Background: Empirically prescribed antibiotics are widely employed in the management of odontogenic infections.

Objective: To characterise the infections associated with extracted teeth and assess effectiveness of the antibiotics prescribed empirically following tooth extraction.

Methods: The study was cross-sectional and consisted of 41 consecutively recruited subjects who required extraction for infections associated with the tooth. Appropriate clinical specimens were collected aseptically from each patient and transported in Stuart's transport medium for processing in the laboratory. Isolation, identification, and susceptibility pattern of anaerobic and facultative organisms were done employing standard bacteriologic techniques. Antimicrobial susceptibility testing was performed by the disc diffusion technique.

Results: There were positive cultures for 37 patients. Twenty-eight aerobic (45.9%) bacteria and 32 anaerobic (54.1%) bacteria were isolated, an approximation of two microorganisms per patient. Staphylococcus was the most predominant aerobe (25.0%) whereas Bacteroides fragilis was the most predominant anaerobe (34.2%). All the bacteria isolated showed in vitro resistance to cephalexin, cloxacillin and metronidazole. Eighteen (64.3%) different aerobic bacteria and 13 (40.6%) different anaerobic bacteria were sensitive to ciprofloxacillin and these included staphylococcus and Bacteroides fragilis. Sensitivity pattern for amoxycillin was very poor with 3.6% and 6.3% for aerobes and anaerobes respectively.

Conclusion: Odontogenic infections from our centre are polymicrobial in nature with anaerobes predominating. High resistance to most of the antibiotics routinely prescribed in our centre is common. Ciprofloxacillin demonstrated the highest sensitivity pattern.