Colistin- and Carbapenem-Resistant Escherichia coli Harboring mcr-1 and bla _NDM-5 , Causing a Complicated Urinary Tract Infection in a Patient from the United States

Abstract

Colistin is increasingly used as an antibiotic of last resort for the treatment of carbapenem-resistant Gram-negative infections. The plasmid-borne colistin resistance gene mcr-1 was initially identified in animal and clinical samples from China and subsequently reported worldwide, including in the United States. Of particular concern is the spread of mcr-1 into carbapenem-resistant bacteria, thereby creating strains that approach pan-resistance. While several reports of mcr-1 have involved carbapenem-resistant strains, no such isolates have been described in the United States. Here, we report the isolation and identification of an Escherichia coli strain harboring both mcr-1 and carbapenemase gene blaNDM-5 from a urine sample in a patient without recent travel outside the United States. The isolate exhibited resistance to both colistin and carbapenems, but was susceptible to amikacin, aztreonam, gentamicin, nitrofurantoin, tigecycline, and trimethoprim-sulfamethoxazole. The mcr-1- and blaNDM-5-harboring plasmids were completely sequenced and shown to be highly similar to plasmids previously reported from China. The strain in this report was first isolated in August 2014, highlighting an earlier presence of mcr-1 within the United States than previously recognized.

Various Sequence Types of Escherichia coli Isolates Coharboring bla NDM-5 and mcr-1 Genes from a Commercial Swine Farm in China

“…In a short period, colistin-resistant E. coli carrying the mcr-1 gene were reported worldwide (19,20). Recently, mcr-1 was reported to coexist with bla NDM (21)(22)(23) and bla CTX-M (24), which brought great challenges for the treatment of bacterial infection. In the present study, we are the first to report the presence of isolates of various sequence types of E. coli coharboring bla NDM-5 and mcr-1 genes from a commercial pig farm in China.…”

Efflux in the Oral Metagenome: The Discovery of a Novel Tetracycline and Tigecycline ABC Transporter

“…This work also shows that the human oral cavity harbors unknown tetracycline resistance determinants in the absence of any obvious selection pressure. There is potential for these genes to be acquired by mobile genetic elements and transferred to bacterial pathogens, which is particularly worrying given the recent identification of a carbapenem and colistin resistant strains of E. coli some of which could only be inhibited by doxycycline and tigecycline (Liu et al, 2016; Mediavilla et al, 2016; Yao et al, 2016). However, the associated fitness cost of tet AB(60) observed in E. coli may limit any possible fixation following dissemination of the genes from their native host to E. coli strains in the absence of a tetracycline or tigecycline selective pressure.…”

Investigation ofEscherichia coliHarboring themcr-1Resistance Gene — Connecticut, 2016

“…Plasmids can be transferred between bacteria, potentially spreading the resistance gene to other bacterial species. Since its discovery, the mcr-1 gene has been reported from Africa, Asia, Europe, South America, and North America (2,3), including the United States, where it has been identified in Escherichia coli isolated from three patients and from two intestinal samples from pigs (2,(4)(5)(6). In July 2016, the Pathogen Detection System at the National Center for Biotechnology Information (Bethesda, Maryland) identified mcr-1 in the whole genome sequence of an E. coli isolate from a Connecticut patient (7); this is the fourth isolate from a U.S. patient to contain the mcr-1 gene.…”