Frequency of integrons 1 and 2 and their relationship with drug resistance patterns of Salmonella isolates in patients with gastroenteritis in Tehran, Iran

Salmonella is one of the most important bacteria that causes gastroenteritis in humans and the spread of Salmonella strains with multidrug resistance is an acute global problem. Integrons are one of the most important factors responsible for transfering of drug resistance genes among Salmonella serotypes. In the present study, the frequency of class 1 and class 2 integrons as well as their relationship with drug resistance patterns in patients with gastrointestinal symptoms were investigated.

In this cross-sectional study, 400 human fecal samples with gastrointestinal symptoms were collected from 4 hospitals in Tehran. All the samples were analyzed by standard method for microbial culture and the results were confirmed by biochemical and PCR tests. Antimicrobial susceptibility testing was performed by disk diffusion method. After DNA extraction, the presence of class 1 and 2 integrons was investigated by PCR. Statistical analysis for detection of correlation between the presence of integrons and resistance patterns was done using SPSS software and Fisherʼs exact test.

The results showed that Salmonella was present in 5.5% (22.400) of the stool specimens. The prevalence rates of class 1 and 2 integrons for human stool specimens were 40.9% (9/22) and 27.2% (6/22), respectively. MDR phenotype was detected in 4.5% (1.22) of the Salmonella isolates from patients with gastroenteritis.

In this study, high levels of integrons 1 and 2 were observed in the patients' Salmonella isolates with gastroenteritis. The observed relationship between drug resistance patterns and the integrons indicated a possible increased risk of drug resistance genes in Salmonella isolates with human gastroenteritis.