Tehran University Medical Journal (Dec 2023)
Investigation of the frequency of resistance to fluoroquinolones in Salmonella enterica subspecies enterica serovar Enteritidis isolates isolated from hospital gastroenteritis samples
Abstract
Background: Salmonella enterica subspecies enterica serotype Enteritidis (S. Enteritidis) is one of the leading causes of food-borne infections associated with the consumption of contaminated food products of animal origin in humans. gastroenteritis due to Salmonella is usually a self-limiting disease and does not require antibiotic therapy. However, antibiotic treatment for salmonellosis may be lifesaving for patients with severe infections.The objective of the present study was to examine antimicrobial resistance and determine its genetic basis in recently isolated S.Enteritidis strains. Methods: During this study, in a cross-sectional descriptive study, 44 isolates of Salmonella enteritidis from human sources were investigated between September 2021 and September 2022.. After identification of the isolates using phenotypic and molecular methods by Multoplex-PCR, antibiotic resistance testing was performed according CLSI 2023. The strains were examined for the presence of qnrA,qnrB,qnrS and gyrA resistance genes by PCR. Results: In a cross-sectional descriptive study, 44 isolates of Salmonella Enteritidis from human sources were investigated between September 2022 and September 2023. 100% of the strains were sensitive to imipenem and meropenem, and the sensitivity to the antibiotics ceftriaxone, ceftazidime, and cefotaxime were 93.2%, 90.9%, and 94.1%, respectively. 81.8% of isolates were sensitive to cotrimoxazole, sensitivity to ampicillin was 84.1%. Only 9.1% of isolates were sensitive to ciprofloxacin. Based on MIC results, 16 isolates had MIC between 0.002 and 0.064 and were placed in the sensitive area. 28 isolates had MIC between 0.125 and 0.5 and were placed in the area of reduced sensitivity. None of the strains resistant to disk diffusion method were resistant to MIC method. qnrA, qnrB and qnrS genes were not observed among ciprofloxacin resistant strains. All nalidixic acid resistant strains had gyrA gene. Conclusion: In general, it was shown in this study that the resistance to the fluoroquinolone family is increasing among Salmonella Enteritidis isolates. On the other hand, we see a decrease in the sensitivity and prevalence of strains resistant to broad-spectrum cephalosporins among serovar Enteritidis, which is the drug of choice for extraintestinal infections.
