The relationship between integrons, antibiotic resistance genes and SXT resistance in strains.

OBJECTIVE

To investigate the correlation between (SXT) resistance in () and the presence of integrons and relevant antibiotic resistance genes.

METHODS

We collected 115 strains of isolated from feces of children with diarrhea in Jinan from 2012 to 2020 and determined the minimum inhibitory concentration (MIC) of SXT by Etest method. The presence of class 1, class 2, and class 3 integron genes, variable region antibiotic resistance gene cassettes, and , and SXT elements were detected using polymerase chain reaction (PCR). Positive results were further analyzed by DNA sequencing and BLAST comparison.

RESULTS

In total, the resistance rate to SXT was 60.9% among the 115 strains. The prevalence of class 1 and class 2 integrons were 88.7% and 87.0%, respectively, with no class 3 integrons detected. Among the strains, 13.0% carried typical class 1 integrons with variable region antibiotic resistance gene cassettes and , while 85.2% carried atypical class 1 integrons with variable region antibiotic resistance gene cassette . The variable region antibiotic resistance gene cassettes of class 2 integrons were all . There was a statistical difference between the presence of class 1 integrons and class 2 integrons between the SXT-sensitive and resistant strains (χ=22.800, χ=16.365, P<0.01, P<0.01). Integrons carrying and by integrons also showed a statistical difference in SXT resistance (χ=9.422, χ=16.365, P<0.01, P<0.01). PCR revealed the presence of and in 13.0% and 47.0% of strains, respectively, with neither nor SXT elements detected. There was a significant difference between the presence of between the SXT-sensitive and resistant strains (χ=9.588, χ=65.445, P<0.01, P<0.01).

CONCLUSION

In summary, integrons are involved in SXT resistance of , and are closely related to SXT resistance of .