Gene expression profiling of antibiotic resistance genes in multidrug-resistant bacteria in Northeast Syria: Evolving challenges in a conflict-affected region.

BACKGROUND

Conflict-affected regions represent under-characterized reservoirs for antimicrobial resistance (AMR), where healthcare disruption, population displacement, limited diagnostic capacity, and sustained antibiotic exposure may accelerate the emergence and dissemination of multidrug-resistant (MDR) pathogens. However, the molecular mechanisms underlying resistance gene regulation in Syria remain poorly characterized.

METHODS

We conducted a cross-sectional quantitative study in hospitals across Northeast Syria between June 2023 and September 2025. A total of 910 patients were screened for bacterial isolation and antimicrobial susceptibility testing. Representative multidrug-resistant isolates were subsequently analyzed using RT-qPCR to investigate transcriptional profiles of 273 resistance-associated genes across seven clinically important bacterial pathogens: Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecalis, Citrobacter freundii, and Staphylococcus aureus. Promoter regions of resistance determinants were sequenced to identify regulatory mutations.

RESULTS

Multiple resistance genes, including blaOXA-23, blaVEB-1, blaVIM, rmpA, blaSHV-1, GIM, and strB, demonstrated significantly elevated transcription in resistant isolates, whereas integron-associated genes, cfxA, and fosA showed no significant differences, potentially reflecting local antibiotic prescribing practices. Promoter analyses revealed recurrent base substitutions, notably a triple TG (TGTGTG) motif within the -18 region, consistent with enhanced transcriptional activity.

CONCLUSION

These findings indicate that sustained antibiotic pressure in conflict settings promotes promoter-level regulatory adaptations that enhance resistance gene expression. Such mechanisms may enable the persistence of multidrug resistance independent of ongoing horizontal gene transfer, highlighting the urgent need for context-specific antimicrobial stewardship in fragile healthcare systems.