Pathogenic bacterial profile and antimicrobial susceptibility patterns in odontogenic facial cellulitis among Egyptian patients: A cross-sectional study.

Odontogenic facial cellulitis is the most common facial space infection worldwide, originating from untreated dental caries and progressing to life-threatening complications. This stems from the polymicrobial nature of the disease, along with the widespread and over-the-counter misuse of antibiotics in Egypt. This study aims to identify the pathogenic bacterial species involved in odontogenic facial cellulitis in an Egyptian patient sample. Forty-four samples were collected from patients presenting with odontogenic facial cellulitis. Bacterial profiles were investigated using selective media, Gram staining/colony identification, biochemical tests, and Clinical and Laboratory Standards Institute standardized antibiotic susceptibility testing. Resistant strains (≥ 3 agents) were identified using 16 S rRNA sequencing and deposited in the NCBI GenBank. Odontogenic cellulitis originated primarily from lower posterior teeth, specifically the lower first molar, and spread commonly in the submandibular and submental spaces. Regarding bacterial profile, the Gram-positive cocci were the predominant ones. Complete resistance to metronidazole was reported, while previous antibiotic administration showed no statistically significant association with susceptibility to amoxicillin and clindamycin. Among multidrug-resistant isolates, 16 S rRNA sequencing identified predominantly Bacillus, Enterococcus, and Staphylococcus species. Two isolates showed < 90% identity to known species, suggesting possible novel taxa and informing empirical therapy through phenotypic resistance profiles.