the occurrence and characterization of class i, ii, and iii integrons among carbapenemase-producing clinical strains of acinetobacter baumannii in tehran, iran

Background: acinetobacter baumannii has emerged as a critical pathogen with high morbidity and mortality in long-term hospitalized patients who stay in intensive care units. carbapenemases and integrons are two critical dna elements that contribute to the emergence of multidrug-resistant (mdr) a. baumannii. objectives: the current study aimed at characterization and molecular detection of class 1, 2, and 3 integrons among carbapenemase-producing a. baumannii strains recovered from a clinical setting in tehran, iran. methods: a total of 65 non-replicated clinical strains were considered in this study. class 1, 2, and 3 carbapenemase genes and clonal relatedness of the isolates were investigated by pcr assay. results: the prevalence of carbapenemases was as follows: blaoxa23 (92.31%), blavim (69.23%), and blandm (1.54%). in addition, pcr sequencing confirmed the presence of gene cassette arrays consisting of aaca4-catb8-aada1 (12/46, 26.09%), aadb-aada1 (26.09%, 12/46), arr2-cm1a5 (30.43%, 14/46), and dfra1-aada1 (7.39%, 8/46) in class 1 integron and dfra1-sat2 (52.94%, 9/17), and sat2-aada1 (47.06%, 8/17) in class 2 integron. sequence-based typing of both blaoxa-51-like and ampc revealed the following distribution of three different clone types among isolates: clonal complex (cc) 10 (46.15%, 30/65), cc2 (40%, 26/65), and cc3 (13.85%, 9/65). statistical analysis showed that the presence of the inti1, blaoxa23, blavim, or blandm genes can significantly increase the acquiring mdr phenotypes in a. baumannii isolates. conclusions: high prevalence of carbapenemase-producing a. baumannii harboring integrons is alarming public health. it seems that class 1 integron can be served as a predictive biomarker for the presence of mdr phenotypes in the clinical setting. however, integrons do not carry carbapenemases in these strains.