Molecular and Phenotypic Characteristics ofEscherichia coliIsolates from Farmed Minks in Zhucheng, China

Abstract

In this study, the prevalence, phenotypes, and clonal relationships of Escherichia coli (E. coli) strains isolated from minks were investigated. In July 2017, a total of 62 fresh faecal swab samples were randomly collected from one large-scale mink farm in Zhucheng, Shandong Province, China. In all the samples, 50 E. coli strains were isolated and then assigned to serotyping, antimicrobial susceptibility test, detection of antimicrobial resistance genes and the Class 1 integrons, and multilocus sequence typing (MLST). Four pathogenic serotypes were identified among all the isolates, while the most common serotype was enterohemorrhagic E. coli O104:H4 (6.0 %). Antimicrobial sensitivity testing revealed that most isolates were susceptible to cefoxitin (96.0 %) and amikacin (82.0 %), while most isolates were resistant to ampicillin (92.0 %) and tetracycline (90.0 %). An analysis of the nucleotide sequences revealed that 7 isolates (14.0%) carried 4 types of Class 1 integron cassette, including dfrA27+aadA2+qnrA (57.1%), dfrA17+aadA5 (14.3%), dfrA12+aadA2 (14.3%), and dfrA1+aadA1 (14.3%). PCR screening showed that 14 antibiotic resistance genes were presented in 50 isolates, while the most prevalent resistance gene was qnrS, which was detected in 60.0 % of isolates, followed by sul2 (40.0%) and oqxA (38.0%). MLST analysis showed that 32 sequence types (STs) were identified, while ST46 was the predominant genotype among all isolates. Clonal complex 3 (CC3) was dominant. Compared with 340 human E. coli STs reported in China, the ST10 clonal complex, known as the largest human clonal complex, was also found in the 50 mink E. coli isolates. Meanwhile, mink-derived strain ST206 formed a new clonal complex, CC206, which was different from human ST strains. Our results showed that farmed minks could be reservoirs of antimicrobial-resistant E. coli with Class 1 integron cassettes and resistance genes, which were likely to pose a threat to public health. Therefore, continuous inspections and monitoring of E. coli in minks are essential for detecting and controlling emerging E. coli with different serovars as well as antibiotic resistance.

Plasmid mediated colistin resistant mcr-1 and co-existence of OXA-48 among Escherichia coli from clinical and poultry isolates: first report from Nepal

“…Another study reported from Iran had showed 77.7% resistance to ciprofloxacin, 33.3% resistance to gentamicin but no resistance to Imipenem [39]. A study from China reported higher rate of resistance to tetracycline (90%), cefixime (71.4%), and ceftazidime (66.1%) in E. coli isolates [33]. Another study from Pakistan reported higher resistance to gentamicin (77%) and ciprofloxacin (65%) in clinical isolates of Enterobacteriaceae [40].…”

“…However, similar study from Bangladesh reported 100% MDR in E. coli isolates [43]. Open access between poultry farms and communities, unhygienic practice, inappropriate use of antibiotics, are some of the reasons attributed for emerging resistance patterns including MDRs in Nepal [33,43,44].…”

Prevalence of avian-origin mcr-1–positive Escherichia coli with a potential risk to humans in Tai'an, China

“…Pulsotypes A, E, I, and K (the epidemic strains) were distributed and disseminated among poultry in the Tai'an area. Multilocus sequence typing provides a scalable typing system that reflects the population and evolutionary biology of E. coli , thereby enabling valid comparisons of the results from different laboratories ( Qiu et al., 2019 ). Multilocus sequence typing of these 27 poultry-origin POL-resistant E. coli strains also showed diversity among the isolates.…”

Synergism of the Combination of Traditional Antibiotics and Novel Phenolic Compounds against Escherichia coli

“…Many E. coli strains in the intestinal tract of humans and animals are considered as commensal members of the microbiota [ 1 ]. However, some strains, including enteropathogenic E. coli , enteroinvasive E. coli , enteroaggregative E. coli , enterotoxigenic E. coli , and enterohemorrhagic E. coli , are highly pathogenic, and may initiate a wide spectrum of diseases ranging from self-limiting to life-threatening intestinal and extra-intestinal illnesses, such as enteritis, pyelonephritis, enterotoxaemia, mastitis, cystitis, meningitis, septicemia, and arthritis [ 1 , 2 , 3 ]. Antibiotics have long been considered the first line of defense to prevent pathogenic E. coli -associated infections.…”

“…Antibiotics have long been considered the first line of defense to prevent pathogenic E. coli -associated infections. However, the treatment of pathogenic E. coli has become complicated by the rapid emergence and dissemination of antibiotic-resistant strains [ 2 ].…”