Quinolone resistance mutations in the faecal microbiota of Swedish travellers to India. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Johnning, Anna; Kristiansson, Erik; Angelin, Martin; Marathe, Nachiket; Shouche, Yogesh; Johansson, Anders; Larsson, D.
• Is Part Of: BMC microbiology. Volume 15:Issue 1(2015)
• Page Start: 1
• Page End: 8
• Publication Date: 2015-12
• Subjects: Antimicrobial resistance -- Gut microbiota -- 454 sequencing -- Fluoroquinolones; Microbiology -- Periodicals; 579.05
• DOI: 10.1186/s12866-015-0574-6
• Languages: English
• ISSNs: 1471-2180

Abstract

Abstract Background International travel contributes to the spread of antibiotic resistant bacteria over the world. Most studies addressing travel-related changes in the faecal flora have focused on specific mobile resistance genes, or depended on culturing of individual bacterial isolates. Antibiotic resistance can, however, also spread via travellers colonized by bacteria carrying chromosomal antibiotic resistance mutations, but this has received little attention so far. Here we aimed at exploring the abundance of chromosomal quinolone resistance mutations inEscherichia communities residing in the gut of Swedish travellers, and to determine potential changes after visiting India. Sweden is a country with a comparably low degree of quinolone use and quinolone resistance, whereas the opposite is true for India. Methods Massively parallel amplicon sequencing targeting the quinolone-resistance determining region ofgyrA andparC was applied to total DNA extracted from faecal samples. Paired samples were collected from 12 Swedish medical students before and after a 4–15 week visit to India. Twelve Indian residents were included for additional comparisons. Methods known resistance mutations were common in Swedes before travel as well as in Indians, with a trend for all mutations to be more common in the Indian sub group. There was a significant increase in the abundance of the most common amino acid substitution in GyrA (S83L, from 44 to 72 %, p = 0.036) in the samples collected after return to Sweden. No other substitution, including others commonly associated with quinolone resistance (D87N in GyrA, S80I in ParC) changed significantly. The number of distinct genotypes encoded in each traveller was significantly reduced after their visit to India for both GyrA (p = 0.0020) and ParC (p = 0.0051), indicating a reduced genetic diversity, similar to that found in the Indians. Conclusions International travel can alter the composition of theEscherichia communities in the faecal flora, favouring bacteria carrying certain resistance mutations, and, thereby, contributes to the global spread of antibiotic resistance. A high abundance of specific mutations in Swedish travellers before visiting India is consistent with the hypothesis that these mutation have no fitness cost even in the absence of an antibiotic selection pressure.