Materials and Methods: A hospital based descriptive cross-sectional study was conducted from January to December 2019; pus was aspirated from Dentoalveolar abscess in 60 patients, the specimen collected, transported anaerobically and was subjected to standard methods for isolation and identification of microorganisms, Antimicrobial susceptibility testing to different agents was carried out using the disc diffusion method, all demographic, clinical, laboratory data and results of cultures were collected for each case. Continuous variables are described as mean ± SD and were compared using unpaired Student’s t-test, for independent Categorical variables are described as (%) compared by chi square test or fisher exact test as appropriate. A p value < 0.05 was considered significant.

Results: A total of 92 anaerobes were isolated, the prevalence of Gram-positive was high (p<0.001) 33 of them were Peptostreptococcus, 29 Peptococccus, 16 Fusobacterium, 8 Prevotella, 6 were Bacteroides, Metronidazole was the most sensitive drug (100%) followed by Ciprofloxacin, Amoxicillin/clavulanic acid (90%), Clindamycin (85%) and Cefotaxime (75%). The Amoxicillin was 100% resistant.

Conclusions: Anaerobic bacteria are prevalent in Dentoalveolar abscess, they are subjected throughout life to a continuous challenge by antimicrobial agents used in clinical therapy, and high prevalence of bacterial resistance to ampicillin suggests the need for regular antibiotic susceptibility tests and rational use of antibiotics in the management of these infections.