First report of ciprofloxacin-resistant Salmonella Enteritidis isolated from human cases in Morocco.

INTRODUCTION

Salmonella enterica serovar Enteritidis is a principal cause of foodborne and invasive infections worldwide. Ciprofloxacin continues to be a primary treatment for invasive cases, but resistance has emerged in several regions. In Morocco, although S. Enteritidis is frequently isolated, no ciprofloxacin-resistant isolates have been reported to date.

METHODOLOGY: A total of 60 Salmonella strains were detected in clinical samples from the Mohammed VI University Hospital Center in Marrakech between 2018 and 2024. Strain S54 was identified as S. Enteritidis by serotyping. Antimicrobial susceptibility testing was performed by disk diffusion. Whole-genome sequencing was conducted using Illumina technology, and resistance and virulence determinants were analyzed with ResFinder, PlasmidFinder, and VFDB databases.

RESULTS

Three isolates (5%), including the S54 strain, showed resistance to ciprofloxacin. Genomic analysis identified a D87Y substitution in gyrA and the presence of efflux genes (mdsA, mdsB). Several virulence genes, including those located in SPI-1 and SPI-2, were also detected.

CONCLUSIONS

This study represents the first report of a ciprofloxacin-resistant S. Enteritidis strain in Morocco. These findings highlight the urgent need to strengthen molecular surveillance and implement preventive measures against fluoroquinolone-resistant Salmonella.