Background: Integrons are genetic elements which are known for their role in capturing and spreading of antibiotic resistance determinants among Gram-negative bacilli. So far, there is no study regarding Class 3 integron and their genetic organisation in India.
Objective: This study investigates the occurrence of Class 3 integron and their gene cassette array among Escherichia coli.
Materials and methods: In this study, a total of 200 E. coli isolates were collected from indoor and outdoor patients from Silchar Medical College and Hospital during September 2015 to February 2016. Detection of the integrase genes and gene cassettes within the Class 3 integron was performed by polymerase chain reaction which was further analysed by sequencing.
Results: Twenty-seven isolates were found to harbour Class 3 integron. Sequencing of the gene cassettes and whole Class 3 integron revealed the presence of nine different types of cassettes array, out of which the arrangement with glycerol kinase gene cassette was found to be the most prevalent. Arrangement with blaCTX-Mgene cassette was also detected in few isolates.
Conclusion: This study provides epidemiological profiling of Class 3 integrons in this geographical area. The data generated in this study are helpful in infection control programme, anti-infective research and search for epidemiological markers.
Keywords: Class 3 integron; Enterobacteriaceae; gene cassette; integrase; multidrug resistance.