Infection by and dissemination of NDM-5-producing Escherichia coli in China: Table 1.

This study investigated the characteristics of Escherichia coli isolates carrying mcr-1-bla NDM from a chicken farm in China. Of the 78 E. coli isolates, 21 clonally unrelated isolates carried mcr-1-bla NDM . Diverse IncI2 plasmids disseminated mcr-1, while the dissemination of bla NDM was mediated by diverse IncB/O plasmids. More striking was the colocalization of resistance genes mcr-1 and bla in an IncHI2/ST3 plasmid, which might pose a great challenge for public health.KEYWORDS high incidence, mcr-1, bla NDM , colocalization, Escherichia coli C arbapenems have been reliable and potent agents against Gram-negative bacteria. The rapid increase of carbapenem-resistant Enterobacteriaceae poses a great threat to public health and has prompted the reconsideration of colistin as a last-resort therapeutic option (1). Recently, a plasmid-borne colistin resistance gene (mcr-1) was identified in Escherichia coli and Klebsiella pneumoniae strains from animals and humans in China (2). This finding foreshadowed the inevitable dissemination of colistin resistance worldwide and was confirmed by the presence of mcr-1 in other countries (3-6).The mcr-1 gene is often associated with the extended-spectrum ␤-lactamase gene and has been found with bla CTX-M in the same plasmid (4,7,8). The mcr-1 gene has also emerged in carbapenem-resistant isolates (4, 9, 10), and the cotransfer of mcr-1 and carbapenem resistance genes is obviously of great clinical concern. Recently, mcr-1 was even found with bla NDM in the same IncX3-X4 hybrid plasmid in E. coli from pets in China (11). However, only a few isolates resistant to both carbapenem and colistin were characterized in those previous studies.Food-producing animals, especially chickens, serve as resistance gene "reservoirs," so it is crucial to identify the origins of multidrug-resistant plasmids in these animals. In this study, we investigated the genetically diverse E. coli isolates carrying mcr-1 and bla NDM from a chicken farm and characterized the plasmids harboring mcr-1 or bla NDM .Seventy-eight E. coli isolates were collected from diseased chickens in four separate barns on a large chicken farm (100,000 animals) in Shandong Province, China in October 2015. Feces from chickens that showed signs of diarrhea were randomly collected and streaked onto MacConkey agar. After incubating at 37°C for 20 h, one colony with typical E. coli morphology was selected from each chicken sample. Although detailed information on antibiotic usage was not available, ceftiofur and colistin were often used for prophylaxis and treatment of bacterial infections on this farm.Susceptibilities to 18 antimicrobials were determined for these 78 isolates by the agar dilution method using the recommended breakpoints (12, 13). The colistin breakpoint (Ն2 g/ml) was used according to recommendations by the European Committee for Antimicrobial Susceptibility Testing.

contrasting

confidence: 99%

High Incidence of Escherichia coli Strains Coharboring mcr-1 and bla _NDM from Chickens

Liu

Song

Zou

et al. 2017

“…The NDM-5-encoding gene bla was first identified in an Escherichia coli strain recovered from a patient in the United Kingdom in 2011 (3). Since then, bla was identified in many countries, such as Algeria (4)(5)(6), the United States (7), Australia (8), China (9)(10)(11)(12), Denmark (13), Japan (14), India (15), and the United Kingdom (3). The widespread occurrence of NDM-5 in recent years should arouse our attention.…”

mentioning

confidence: 99%

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

Kong

Lei

et al. 2017

Sixteen different sequence types (STs) of Escherichia coli isolates from a commercial swine farm in China were confirmed to coharbor the carbapenem resistance gene bla and the colistin resistance gene mcr-1. Whole-genome sequencing revealed that bla NDM-5 and mcr-1 were located on a 46-kb IncX3 plasmid and a 32-kb IncX4 plasmid, respectively. The two plasmids can transfer together with a low fitness cost, which might explain the presence of various STs of E. coli coharboring bla NDM-5 and mcr-1.KEYWORDS Escherichia coli, carbapenems, bla NDM-5 , colistin, mcr-1, fitness cost C arbapenemase-producing Enterobacteriaceae has become a major public health threat around the world (1). The recently identified carbapenemase New Delhi metallo-␤-lactamase confers resistance to all ␤-lactam antimicrobials except monobactam (2). The NDM-5-encoding gene bla NDM-5 was first identified in an Escherichia coli strain recovered from a patient in the United Kingdom in 2011 (3). Since then, bla was identified in many countries, such as Algeria (4-6), the United States (7), Australia (8), China (9-12), Denmark (13), Japan (14), India (15), and the United Kingdom (3). The widespread occurrence of NDM-5 in recent years should arouse our attention. Colistin is a critically important medication for humans in the treatment of carbapenemaseproducing Enterobacteriaceae, and it has been widely used in veterinary medicine in China (16,17). The first plasmid-mediated colistin resistance gene, mcr-1, was reported in E. coli in 2015 (18). 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 (21-23) 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.A total of 105 anal swabs samples from swine were collected from a commercial pig farm on 1 October 2015 in Sichuan province. E. coli strains were selected by eosinmethylene blue agar, and only 1 isolate was picked up from each sample. All 105 isolates were identified by BD Phoenix 100 diagnostic systems (Sparks, MD). Sixty-four strains were nonsusceptible to imipenem and polymyxin B, identified by the agar dilution method according to Clinical and Laboratory Standards Institute guidelines (25). Isolates were divided into 16 different clones by pulsed-field gel electrophoresis after XbaI digestion according to the standard PulseNet conditions (26) (Fig. 1). Phy-

“…Recently, four studies have reported several sporadic cases of clinical infections linked to E. coli ST167 carrying bla NDM-5 in various parts of China (10-12). The gene was shown to be located on the IncX3 plasmid in two studies (11,12).In this work, we have conducted a more comprehensive investigation in order to better understand whether the E. coli ST167 strains are predominantly involved in the transmission of the bla NDM-1 and bla NDM-5 genes in hospitals in various parts of China. Clinical carbapenem-resistant E. coli strains, as determined by the Kirby-Bauer disk diffusion method according to CLSI guidelines, were obtained from 7 hospitals in various locations in China, as shown in Table 1, from 2013 to 2014.…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Since then, the gene has become detectable in most species of Enterobacteriaceae in various cities in China, and yet, there is a lack of information on the linkage of specific STs of E. coli to bla NDM-1 carriage due to the sporadic and noncomprehensive nature of CRE-related data in China. Recently, four studies have reported several sporadic cases of clinical infections linked to E. coli ST167 carrying bla NDM-5 in various parts of China (10)(11)(12). The gene was shown to be located on the IncX3 plasmid in two studies (11,12).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Widespread Dissemination of Carbapenem-Resistant Escherichia coli Sequence Type 167 Strains Harboring bla _NDM-5 in Clinical Settings in China

Huang

Xie³

et al. 2016

e This study reports the increasing prevalence of clinical Escherichia coli of sequence type 167 (ST167) carrying both bla NDM-1 and bla NDM-5 on the conjugative IncX3 plasmid in various parts of China. Close surveillance is needed to monitor the future dissemination of ST167 strains that harbor bla NDM-5 or other bla NDM -like genes.T he continuous emergence of carbapenem-resistant Enterobacteriaceae (CRE) strains in recent years has posed an increasing public health threat worldwide. The dissemination of mobile resistance elements, especially those carrying the New Delhi metallo-␤-lactamase gene (bla NDM-1 ), has been regarded as a major mechanism responsible for causing a dramatic increase in the prevalence of CRE in clinical settings. NDM-producing organisms were first reported on the Indian subcontinent and then in several Middle Eastern and Balkan countries in 2009 (1, 2). This gene has since spread to different species of Enterobacteriaceae and other Gram-negative bacteria throughout the world (3). The rapid increase in the prevalence of CRE may be due to both transmission of bla NDM-1 -carrying elements among the Enterobacteriaceae species and clonal spread of strains containing such elements (4, 5). Current evidence, however, suggests that the transmission of specific mobile resistance elements in CRE has a strong association with specific types of bacterial strains. For example, the bla NDM-1 -like genes are predominantly detected in multilocus sequence typing (MLST) sequence type 131 (ST131) and ST101 strains of Escherichia coli and ST11 strains of Klebsiella pneumoniae (5-8). The underlying mechanisms leading to the clustering of the bla NDM-1 -like genes in specific STs remain to be investigated.In China, bla NDM-1 was reported in 2011 (9). Since then, the gene has become detectable in most species of Enterobacteriaceae in various cities in China, and yet, there is a lack of information on the linkage of specific STs of E. coli to bla NDM-1 carriage due to the sporadic and noncomprehensive nature of CRE-related data in China. Recently, four studies have reported several sporadic cases of clinical infections linked to E. coli ST167 carrying bla NDM-5 in various parts of China (10-12). The gene was shown to be located on the IncX3 plasmid in two studies (11,12).In this work, we have conducted a more comprehensive investigation in order to better understand whether the E. coli ST167 strains are predominantly involved in the transmission of the bla NDM-1 and bla NDM-5 genes in hospitals in various parts of China. Clinical carbapenem-resistant E. coli strains, as determined by the Kirby-Bauer disk diffusion method according to CLSI guidelines, were obtained from 7 hospitals in various locations in China, as shown in Table 1, from 2013 to 2014. A total of 48 carbapenem-resistant E. coli isolates were obtained during the study period and screened for the presence of bla NDM-1 as previously described (13). Twenty-five (52%) were found to carry bla NDM carbapenemase genes, among which 11 were isolated from p...