PHENOTYPIC AND GENOTYPIC DETECTION OF SERRATIA MARCESCENS EFFLUX PUMPS, BIOFILMS FORMATION, AND ANTIMICROBIAL RESISTANCE PROPERTIES IN DIFFERENT CLINICAL CASES IN WASIT PROVINCE, IRAQ

Abstract

Serratia marcescens Antibiotic-resistant bacteria with efflux pumps and biofilm formation, posing significant challenges in infection management. In the current study, 18 Serratia marcescens isolates were tested for antibiotic susceptibility and the reality resistance mechanisms. The isolates were obtained from urinary tract, wound, and respiratory tract infections.Phenotypicdetection methods, including efflux pumps of the Ethidium bromide-agar cartwheel method and biofilm formation assays, were used. Genotypic detection involved amplification of efflux pump and biofilm formation genes PCR assay using primersspecific for(efflux pumps genesSdeAB-B, SdeCDE-D, SdeXY-Y, and SsmE,and biofilm genes YmgB, BsmA, and HmsP).Gene sequencing was performed and analyzed using BLAST in NCBI and Geneious version -10, revealing similarities between Iraqi S. marcescens and global strains. The results showed that Serratia marcescens isolates exhibited high resistance to AMC (91.59%), CFM (90%), and CTX (87.48%). while they had the lowest resistance to IPM (35%), CIP (25%), and MEM (20%). Phenotypic detection revealed that (77.7%) of the isolates tested positive for efflux pump activity, while all 18 samples tested positive for biofilm formation using both the microtiter plate (MTP) and modified Congo red agar (MCRA) methods. Genotypic detection demonstrated the presence of SdeAB-B, SdeCDE-D, andSsmE (100%), SdeXY-Y (83.33%), genes associated with efflux pumps. For biofilm formation genes, YmgBwas present in (‎94.44%)‎, BsmAin (83.33%), and HmsP in ‎(77.77%) of the samples.‎ In conclusion, efflux pumps and biofilm formation contribute to Serratia marcescens' resistance to antibiotics. Sequencing revealed novel mutations in these genes, potentially impacting bacterial resistance levels. The appearance of these results brought us beyond the currently documented mutations in NCBI.‎

Keywords: Serratia marcescens; Antibiotic resistance; efflux pump; Biofilm formation