MolecularEpidemiology of orf513-Bearing Class 1 Integrons in MultiresistantClinical Isolates from ArgentineanHospitals

Abstract
The spread of orf513-bearing class 1 integrons is associated with blaCTX-M-2 in gram-negative clinical isolates in Argentina, with In35 being the most frequently found integron (74%). Among 65 isolates without blaCTX-M-2, only one harbored a novel orf513-bearing class 1 integron with the dfrA3b gene. The finding of orf513 not associated with class 1 integrons in two gram-positive strains indicates the widespread occurrence of this putative site-specific recombinase.