Acquisition and Loss of CTX-M-Producing and Non-Producing Escherichia coli in the Fecal Microbiome of Travelers to South Asia.

Bevan, Edward R and McNally, Alan and Thomas, Christopher M and Piddock, Laura J V and Hawkey, Peter M (2018) Acquisition and Loss of CTX-M-Producing and Non-Producing Escherichia coli in the Fecal Microbiome of Travelers to South Asia. mBio, 9 (6). ISSN 2150-7511.

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Official URL: https://mbio.asm.org/content/9/6/e02408-18.long

Abstract

Over 80% of travelers from the United Kingdom to the Indian subcontinent acquire CTX-M-producing (CTX-M-EC), but the mechanism of CTX-M-EC acquisition is poorly understood. We aimed to investigate the dynamics of CTX-M-EC acquisition in healthy travelers and how this relates to populations of non-CTX-M-EC in the fecal microbiome. This is a prospective observational study of healthy volunteers traveling from the United Kingdom to South Asia. Fecal samples were collected pre- and post-travel at several time points up to 12 months post-travel. A toothpicking experiment was used to determine the proportion of cephalosporin-sensitive in fecal samples containing CTX-M-EC. MLST and SNP type of pre-travel and post-travel were deduced by WGS. CTX-M-EC was acquired by 89% (16/18) of volunteers. Polyclonal acquisition of CTX-M-EC was seen in 8/15 volunteers (all had >3 STs across post-travel samples), suggesting multiple acquisition events. Indistinguishable CTX-M-EC clones (zero SNPs apart) are detectable in serial fecal samples up to 7 months after travel, indicating stable maintenance in the fecal microbiome on return to the United Kingdom in the absence of selective pressure. CTX-M-EC-containing samples were often co-colonized with novel, non-CTX-M strains after travel, indicating that acquisition of non-CTX-M-EC occurs alongside CTX-M-EC. The same pre-travel non-CTX-M strains (<10 SNPs apart) were found in post-travel fecal samples after CTX-M-EC had been lost, suggesting return of the fecal microbiome to the pre-travel state and long-term persistence of minority strains in travelers who acquire CTX-M-EC. strains which produce CTX-M extended-spectrum beta-lactamases are endemic as colonizers of humans and in the environment in South Asia. This study demonstrates that acquisition of CTX-M-producing (CTX-M-EC) in travelers from the United Kingdom to South Asia is polyclonal, which is likely due to multiple acquisition events from contaminated food and drinking water during travel. CTX-M-EC frequently persists in the fecal microbiome for at least 1 year after acquisition, often alongside newly acquired non-CTX-M strains. In travelers who acquire CTX-M-EC, pre-travel non-CTX-M remains as a minority population in the gut until the CTX-M-EC strains are lost. The non-CTX-M strains are then reestablished as the predominant population. This study has shed light on the dynamics of CTX-M-EC acquisition, colonization, and loss after travel. Future work involving manipulation of nonvirulent resident could be used to prevent colonization with antibiotic-resistant .

Item Type: Article
Subjects: WC Communicabable diseases
WC Communicabable diseases > WC680 Tropical medicine
Divisions: Clinical Support > Infection Control
Clinical Support > Infectious Diseases
Related URLs:
Depositing User: Mr Philip O'Reilly
Date Deposited: 19 Mar 2019 16:14
Last Modified: 19 Mar 2019 16:14
URI: http://www.repository.heartofengland.nhs.uk/id/eprint/1954

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