BACKGROUND AND ABJECTIVESalmonellosis is a major water and food-borne infection worldwide. With high mortality rates particularly among young children, antimicrobial resistant salmonellosis is considered a public health issue in low-income countries. Therefore, the aim of this study was to evaluate the genotypic and phenotypic resistance of third-generation cephalosporins and carbapenems in
Salmonella strains isolated from clinical samples in Mashhad teaching hospitals.MATERIALS AND METHODS In this cross-sectional study, ۶۴ isolates of
Salmonella were obtained from stool, blood, and urine samples of patients in teaching hospitals in Mashhad. Biochemical tests were used to identify and confirm the genus. In addition,
Salmonella antiserum kits were used to diagnose different serotypes and serogroups of pathogenic Salmonella. The antimicrobial resistance pattern for different antibiotics, including third-generation cephalosporins and meropenem, was determined by the disk diffusion method according to CLSI guidelines. The presence of ESBL, AmpC, and carbapenems encoding genes was evaluated using PCR and sequencing.RESULTS AND DISCUSSIONSalmonella isolates were serotypes A (n=۵, ۷%), B (n=۶, ۱۰%), C (n= ۱۳, ۲۱%), and D (n= ۴۰, ۶۲%). Antibiogram results showed that the most active antibiotics against these bacteria were meropenem (۱۰۰%), gentamicin (۹۷%), and chloramphenicol (۹۴%). Also, the highest antibiotic resistance rates were found for ampicillin (۲۰%) and trimethoprim-sulfamethoxazole (۲۱%). The PCR results showed that ۶ isolates were positive for ESBLs-producing genes, that blaCTX-M-۱۵ and blaTEM were identified in all ۶ samples and blaSHV was identified in one of them. In addition, multiplex-PCR results demonstrated that ۴ isolates (۳ of which were
ESBL positive) produced
AmpC β lactamases, that blaCMY and blaLAT genes were identified in all ۴ samples and blaFOX was in ۳ of them. Due to the lack of identification of meropenem-resistant isolates, PCR was not performed to identify the genes responsible for carbapenem resistance.CONCLUSION The phenotypic and genotypic results found in this study highlight the need for surveillance of antibiotic resistance and screening for
ESBL production to support appropriate action.