Molecular detection of virulence genes of Serratia marcescens isolates from diverse clinical sources

Serratia marcescens is a rare opportunistic pathogen that produces a red pigment and possess a serious threat to vulnerable people in healthcare settings. This study aimed to identify the virulence genes (cnfI, sat, hlyA, PhIA, ShIA, ShIB, swr, and sepA) in clinical isolates of S. marcescens. For that purpose, 152 samples were collected from various clinical sources including burns, wounds, and urinary tract infections. Cultural characteristics and biochemical tests were relied upon for the initial diagnosis. The diagnosis was confirmed using the Vitek-2 system and the final determination for S. marcescens was achieved via sequencing of the 16S rRNA. Only 5/152 (3.28%) samples were confirmed as S. marcescens via 16S rRNA sequencing. Out of 8 virulence factors studied, only hlya and phIA were detected 60% and 80% were detected, respectively. The number of infections with S. marcescens is constantly increasing in Iraq and determining the virulence genes is crucial in order to identify the spread of virulent strains in patients.