Molecular profiling of toxin–antitoxin systems and their association with antimicrobial resistance in Pseudomonas aeruginosa clinical isolates

Background: Pseudomonas aeruginosa is an opportunistic multidrug-resistant pathogen causing healthcare-associated infections. This study evaluated the prevalence of type II toxin–antitoxin (TA) systems higBA and relBE in clinical isolates and examined their potential association with antibiotic resistance. Methods: 150 clinical specimens (burn, ear, and urine) were collected from patients at four hospitals in Basrah city. Identification of the isolates was performed by standard microbiological methods and confirmed by the VITEK system. DNA was extracted using the Promega kit. TA genes were identified by PCR. Results: A total of 50 (33.3%) Pseudomonas aeruginosa isolates were identified from 150 clinical samples, mainly from burns isolates 28 (56%), followed by ear isolates 13 (26%) and urine isolates 9 (18%). The resistance patterns of P. aeruginosa clinical isolates to various antibiotics showed that (75.5%), (67.3%), (75.5%), (76%), (76%), (76%), (66%), (46%), (80%) and (88%) of P. aeruginosa isolates were resistant to TZP, CZA, C/T, CAZ, FEP, IPM, MEM, CST, GEN and CIP respectively. relBE and higBA genes were detected in 96% and 90% of isolates respectively, without significant differences among isolates types or resistance patterns (p > 0.05). Conclusion: higBA and relBE are widely distributed among P. aeruginosa clinical isolates and may function in stress adaptation and persistence rather than direct antimicrobial resistance.