Serratia nevei in Nigeria: First Report and Global Distribution

<i>Serratia</i> species are opportunistic human pathogens found in diverse environmental habitats. Here, we report the first isolation of <i>Serratia nevei</i> from food samples in Nigeria. During a two-month epidemiological surveillance at a local food market in Dutsin-Ma, Katsina State, Nigeria, a total of 180 food samples were collected, and isolation and species identification were performed using chromogenic agar and MicroScan autoSCAN-4, respectively. Antimicrobial susceptibility and minimum inhibitory concentrations (MICs) were determined using the MicroScan autoSCAN-4 system. Strain F129B, recovered from a fresh, unprocessed beef sample, was initially identified as <i>Klebsiella pneumoniae</i> by chromogenic agar and MicroScan autoSCAN-4, and subsequently as <i>Serratia marcescens</i> by MALDI-TOF MS. Only Whole Genome Sequencing (WGS) and bioinformatics analyses confirmed its identity as <i>S. nevei</i>. The strain was then selected for further characterization by Whole Genome Sequencing (WGS) and bioinformatics analyses to confirm its identity. The strain was phenotypically resistant to amoxicillin/clavulanic acid and colistin, with elevated MICs for aztreonam (4 mg/L) and cefuroxime (16 mg/L). In silico analyses of its genome confirmed the isolate as <i>S. nevei</i>, harboring genes conferring resistance to β-lactams (<i>blaSTR-2</i>), aminoglycosides (<i>aac</i> (<i>6'</i>)<i>-Ic</i>), fosfomycin (<i>fosA</i>), streptomycin (<i>satA</i>), and tetracycline (<i>tet</i> (<i>41</i>)). Its virulence repertoire comprises genes associated with adhesion (<i>yidE</i>, <i>yidR</i>, <i>yidQ</i>), colicin tolerance (<i>creA</i> and <i>creD</i>), and heavy metal resistance (<i>czcD</i>, <i>chrBACF</i> operon). These findings underscore the need for genomic characterization for accurate species identification within the <i>Serratia</i> genus. Our findings revealed the emergence of <i>S. nevei</i> in the food supply chain and highlighted its potential for zoonotic transmission. Robust surveillance of the local food supply chain is urgently needed in north-western Nigeria.