Novel environmental class 1 integrons and cassette arrays recovered from an on-farm bio-purification plant

MARTINI, MARÍA CARLA; QUIROGA, MARÍA PAULA; PISTORIO, MARIANO; LAGARES, ANTONIO; CENTRÓN, DANIELA; DEL PAPA, MARÍA FLORENCIA

FEMS Microbiology Ecology

Federation of European Microbiological Societies - FEMS

Año: 2017 vol. 94 p. 1 - 9

Rapid dissemination and emergenceof novel antibiotic resistance genes among bacteria are rising problemsworldwide. Since their discovery in clinical isolates in the late 1980s, class1 integrons have been found in a wide range of bacterial genera and have beenextensively studied as contributors to dissemination of antibiotic resistance.The present study aimed to investigate the presence and structure of class 1integrons in plasmid-carrying bacterial isolates obtained from a biopurificationsystem used for decontamination of pesticide-contaminated water as well astheir possible role as reservoir of antimicrobial resistance gene cassettes. Atotal of 35 representative isolates were screened for the presence of class 1 integronintegrase encoded by intI1. PCR and DNA sequencing revealed the presence of sixclass 1 integrons with four variable regions: 5?CS-aadA1b-3?CS, 5?CS-aadA2-3?CS, 5?CS-aadA11c_-3?CS and 5?CS-dfrB3-aadA1di-catB2-aadA6k-3?CS, the last two being unseenarrays of antimicrobial resistance gene cassettes associated with novelenvironmental alleles of intI1. These four class 1 integrons were identified as beingpresent in four different genera, including Ochrobactrum, and Variovorax, where class 1 integrons have notbeen previously reported. The results provide evidence of the biopurification systemsas a tank of class 1 integron carrying strains and novel environmental class 1integron integrases associated with antimicrobial resistance gene cassettearrays.