AUTHOR=Jones-Dias Daniela , Manageiro Vera , Ferreira Eugénia , Barreiro Paula , Vieira Luís , Moura Inês B. , Caniça Manuela 

TITLE=Architecture of Class 1, 2, and 3 Integrons from Gram Negative Bacteria Recovered among Fruits and Vegetables

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01400

DOI=10.3389/fmicb.2016.01400

ISSN=1664-302X

ABSTRACT=<p>The spread of antibiotic resistant bacteria throughout the food chain constitutes a public health concern. To understand the contribution of fresh produce in shaping antibiotic resistance bacteria and integron prevalence in the food chain, 333 antibiotic resistance Gram negative isolates were collected from organic and conventionally produced fruits (pears, apples, and strawberries) and vegetables (lettuces, tomatoes, and carrots). Although low levels of resistance have been detected, the bacterial genera identified in the assessed fresh produce are often described not only as environmental, but mostly as commensals and opportunistic pathogens. The genomic characterization of integron-harboring isolates revealed a high number of mobile genetic elements and clinically relevant antibiotic resistance genes, of which we highlight the presence of as <italic>mcr-1, qnrA1, bla</italic><sub>GES−11</sub>, <italic>mphA</italic>, and <italic>oqxAB</italic>. The study of class 1 (<italic>n</italic> = 8), class 2 (<italic>n</italic> = 3) and class 3 (<italic>n</italic> = 1) integrons, harbored by species such as <italic>Morganella morganii, Escherichia coli, Klebsiella pneumoniae</italic>, led to the identification of different integron promoters (PcW, PcH1, PcS, and PcW<sub>TNG−10</sub>) and cassette arrays (containing <italic>drfA, aadA, cmlA, estX, sat</italic>, and <italic>bla</italic><sub>GES</sub>). In fact, the diverse integron backbones were associated with transposable elements (e.g., Tn<italic>402</italic>, Tn<italic>7, ISCR</italic>1, Tn<italic>2</italic><sup>*</sup>, IS<italic>26</italic>, IS<italic>1326</italic>, and IS<italic>3</italic>) that conferred greater mobility. This is also the first appearance of In<italic>1258</italic>, In<italic>1259</italic>, and In<italic>3-13</italic>, which should be monitored to prevent their establishment as successfully dispersed mobile resistance integrons. These results underscore the growing concern about the dissemination of acquired resistance genes by mobile elements in the food chain.</p>