Comparative Genome Study of Multidrug-resistantSerratia marcescensstrain IU-BTGE-M-3 Isolated from a Diarrheal Patient Reveals Antibiotic Resistance Profile

Abstract

Serratia marcescensis a notable pathogen known for its intrinsic and acquired antimicrobial resistance, posing challenges in healthcare. The study investigates the multidrug-resistant (MDR)Serratia marcescensstrain BTGE-M-3, focusing on its genomic features and antibiotic resistance. The strain was identified using both morphological and molecular approaches, and its genome, which measured 4.97 Mbp and exhibited a GC content of 59.7%, was sequenced. The genome has 4,827 genes, including essential antibiotic resistance genes, such astet(41) for tetracyclines,aac(6′)-Icfor aminoglycosides,OqxBfor fluoroquinolones, andblaSST-1 beta-lactam, alongside various virulence determinants. Comparative genomics revealed high similarity (98.06% ANI) toS. marcescensstrain KS10, supporting its classification within the same species. Additionally, the genome analysis showed thatS. marcescensstrain IU-BTGE-M-3 comprises of 4390 gene clusters, 4564 genes, and 244 unique singleton genes. To summarize, the results showed thatS. marcescensstrain IU-BTGE-M-3 exhibited a high level of genomic diversity as well as diverse metabolic, cellular, and biological functions, and it is hypothesized that frequent strain exchanges resulted in the horizontal transfer of drug resistance genes. This study underscores the importance of genomic surveillance in understanding and combating antibiotic resistance in therapeutic settings.