mcr-1 Identified in Fecal Escherichia coli and Avian Pathogenic E. coli (APEC) From Brazil

Abstract

Colisitin-associated resistance in bacteria of food producing animals has gained significant attention with the mcr gene being linked with resistance. Recently, newer variants of mcr have emerged with more than nine variants currently recognized. Reports of mcr associated resistance in Escherichia coli of poultry appear to be relatively limited, but its prevalence requires assessment since poultry is one of the most important and cheapest sources of the world’s protein and the emergence of resistance could limit our ability to treat disease outbreaks. Here, 107 E. coli isolates from production poultry were screened for the presence of mcr 1–9. The isolates were collected between April 2015 and June 2016 from broiler chickens and free-range layer hens in Rio de Janeiro, Brazil. All isolates were recovered from the trachea and cloaca of healthy birds and an additional two isolates were recovered from sick birds diagnosed with colibacillosis. All isolates were screened for the presence of mcr-1 to 9 using PCR and Sanger sequencing for confirmation of positive genes. Additionally, pulse field gel electrophoresis (PFGE) analysis, avian fecal E. coli (APEC) virulence associated gene screening, plasmid replicon typing and antimicrobial resistance phenotype and resistance gene screening, were also carried out to further characterize these isolates. The mcr-1 gene was detected in 62 (57.9%) isolates (61 healthy and 1 APEC) and the mcr-5 gene was detected in 3 (2.8%) isolates; mcr-2, mcr-3, mcr-4, mcr-6, mcr-7, mcr-8, and mcr-9 were not detected in any isolate. In addition, mcr 1 and 5 positive isolates were phenotypically resistant to colistin using the agar dilution assay (> 8ug/ml). PFGE analysis found that most of the isolates screened had unique fingerprints suggesting that the emergence of colistin resistance was not the result of clonal dissemination. Plasmid replicon types IncI2, FIB, and B/O were found in 38, 36, and 34% of the mcr positive isolates and were the most prevalent replicon types detected; tetA and tetB (32 and 26%, respectively) were the most prevalent antimicrobial resistance genes detected and iutA, was the most prevalent APEC virulence associated gene, detected in 50% of the isolates. Approximately 32% of the isolates examined could be classified as APEC-like, based on the presence of 3 or more genes of APEC virulence associated path panel (iroN, ompT, hlyF, iss, iutA). This study has identified a high prevalence of mcr-1 in poultry isolates in Brazil, suggesting that animal husbandry practices could result in a potential source of resistance to the human food chain in countries where application of colistin in animal health is practiced. Emergence of the mcr gene and associated colisitin resistance in production poultry warrants continued monitoring from the animal health and human health perspective.

The Occurrence and Genomic Characteristics of mcr-1-Harboring Salmonella from Retail Meats and Eggs in Qingdao, China

“…As colistin has been a last-resort antimicrobial for defending against MDR Gram-negative bacteria, we are surprised to see the high detection rate of mcr-1 in Salmonella from food products. Given mcr-1 has been found in Salmonella from animals in many countries [ 6 , 53 ] and also occurred in Salmonella of human origin [ 17 , 19 ], food products, especially fresh eggs, may play a key role in disseminating such pathogens between animals and humans. In this study, all the mcr-1 -positive Salmonella isolates were ST34 S .…”

“…The mcr-1 gene has been reported in plasmids with different replicon types including IncI2, IncX4, IncHI2, IncHI1, IncP, IncFII and IncFIB [ 1 , 17 ], and the primary replicon type varies among different Enterobacteriaceae members. For instance, IncI2 and IncX4 were the two primary replicon types of plasmids harboring mcr-1 in E. coli from animals [ 6 ] and humans [ 5 ]. However, mcr-1 -carrying IncHI2 plasmid was the primary type in Salmonella from animals [ 57 ] and humans [ 17 ].…”

“…To date, several subtypes of mcr ( mcr-1 to mcr-10 ) have been identified in various Enterobacteriaceae members [ 1 , 3 , 4 ]. The mcr-1 gene shows the highest prevalence among members of Enterobacteriaceae, especially Escherichia coli , and has been found in samples of different origins around the world in recent years, including humans [ 5 ], food-producing animals [ 6 ], aquaculture [ 7 ], migratory birds [ 8 ], wild animals [ 9 ], environments [ 10 ], flies [ 11 ], vegetables [ 12 ] and retail meats [ 13 ].…”

Co-Occurrence of NDM-9 and MCR-1 in a Human Gut Colonized Escherichia coli ST1011

“…Plasmid pL889-MCR1 is a 63,050 bp circular plasmid belonging to IncI2, which was associated with the global dissemination of MCR-1-producing E. coli from animal and human sectors. [27][28][29][30][31] Nucleotide sequence alignment indicated that it aligned very well to plasmids pHNTH02-1 (KY693674), pHLJ179-34 (MN232213), and p5CRE51-MCR-1 (CP021176) (Figure 2B). Of note, p5CRE51-MCR-1 carrying isolate was recovered from a urinary tract infection, which represents the first case reported an E. coli strain co-producing MCR-1 and NDM-9.…”

Epidemiology and Traits of Mobile Colistin Resistance (mcr) Gene-Bearing Organisms from Horses

“…An MDR and ESBL-producing ST711 E. coli carrying a new mcr -5 variant, named mcr -5.3 on a novel 5361 bp plasmid, was isolated from the lung tissue of a horse that never received COL and died of pneumonia in 2012 in Brazil [ 55 ], suggesting that E. coli that co-produces MCR-5 and ESBL has been present in South America for at least almost a decade and is associated with difficult-to-treat diseases in horses. The mcr -5 gene has been detected in E. coli isolates from poultry birds in Brazil [ 80 ]. The livestock sector could be the source of mcr -5 in the Brazilian equine sector since massive amounts (up to 10 g/ton of feed) of polymyxins/COL was used in livestock feed as a growth enhancer in Brazil [ 81 ].…”