In Yemen, antimicrobials are administered without prescription and no information is available about the prevalence of antimicrobial resistance of periodontal pathogens. Objective: To assess the prevalence of resistance of four putative periodontal pathogens in a population of dental patients from Yemen to two commonly used antimicrobials in dentistry, ampicillin and metronidazole. Methods: Subgingival plaque was collected from 34 dental patients at three dental clinics in Sana’a, Yemen and immediately transported (transport time: two days) in VMGA III transport medium to the Laboratory of Oral Microbiology, University of Bergen, Norway. At arrival in the laboratory, the samples were plated on blood agar with and without either 2 µg /ml of ampicillin or 2 µg/ml of metronidazole. The plates were then incubated anaerobically for 10 days at 37°C. Speciation of growth was done using whole genomic DNA-DNA probes and checkerboard hybridization. Results:
Porphrymonas gingivalis (
Pg) was identified in 29 of the 34 (85%) samples,
Tanerella forsythensis (
Tf) in 23 (67%),
Fusobacterium nucleatum (
Fn) in 19 (55%), and
Actinobacillus actinomycetemcomitans (
Aa) in 9 (26%) of the 34 samples. Prevalence % (number of isolates testing positive/total number of isolates tested ) of antimicrobals resistance among the isolates were as follows:
| Antimicrobails | Pg | Tf | Fn | Aa |
| Ampicillin | 51% (15/29) | 52% (12/23) | 31% (6/19) | 55% (5/9) |
| Metronidazole | 7% (2/29) | 9% (2/23) | 21% (4/19) | 100% (9/9) |
Conclusions: The high prevalence of ampicillin and metronidazole resistance of the bacteria isolated from the study population indicate that antimicrobial resistance is common among periodontal pathogens in Yemen. It is likely that this is caused by uncontrolled use of antimicrobial agents.