Prevalence of Parabacteroides distasonis in Aleppo governorate and its antibiotic susceptibility profile

Parabacteroides distasonis is a prominent gut commensal with increasing interest due to its metabolic versatility and potential therapeutic applications. Its abundance is influenced by various host-related factors, including diet, medication, antibiotic exposure, and environmental conditions. This study investigated the prevalence of P. distasonis among residents of Aleppo Governorate and assessed its antibiotic susceptibility patterns. Of the 100 stool samples analyzed, 50 were subjected to culture-based isolation, yielding only two P. distasonis isolates, while the remaining 50 samples (25 from healthy individuals and 25 from patients with type 2 diabetes) were analyzed directly by PCR. The two isolates demonstrated broad multidrug resistance, exhibiting elevated MIC values for ampicillin, clindamycin, amoxicillin-clavulanate, metronidazole, and various cephalosporins. Interestingly, the isolate harboring the rfbA gene showed increased susceptibility to cephalosporins and cefoperazone/sulbactam when compared with the rfbA-negative strain. These findings provide the first regional data on P. distasonis in Syria and emphasize its dual role as both a candidate next-generation probiotic and a potential reservoir of antimicrobial resistance. Ongoing surveillance and molecular characterization are warranted to clarify its therapeutic promise and clinical risks.