Molecular Characterization of Integrons in Epidemiologically Unrelated Clinical Isolates of <i>Acinetobacter baumannii</i> from Italian Hospitals Reveals a Limited Diversity of Gene Cassette Arrays

Abstract

Integron carriage by 36 epidemiologically unrelated Acinetobacter baumannii isolates collected over an 11-year period from patients in six different Italian hospitals was investigated. Sixteen type 1 integron-positive isolates (44%) were found, 13 of which carried the same array of cassettes, i.e., aacC1, orfX, orfX', and aadA1a. As ribotype analysis of the isolates demonstrated a notable genetic diversity, horizontal transfer of the entire integron structure or ancient acquisition was hypothesized.