Shafiq Muhammad, Huang Jinhu, Ur Rahman Sadeeq, Shah Jan Mohammad, Chen Li, Gao Yi, Wang Mengli, Wang Liping
Moe Joint International Research Laboratory of Animal Health and Food Safety, Laboratory of Veterinary Pharmacology and Toxicology, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China.
College of Veterinary Sciences and Animal Husbandry, Section Microbiology, Abdul Wali Khan University, Mardan, KP, Pakistan.
Infect Drug Resist. 2019 Jul 16;12:2135-2149. doi: 10.2147/IDR.S209473. eCollection 2019.
The coexistence of mobile colistin (COL)-resistant gene with extended-spectrum beta-lactamase (ESBL) gene in has become a serious threat globally. The aim of this study was to investigate the increasing resistance to COL and in particular its coexistence with ESBL-producing recovered from pig farms in China.
were isolated from 14 pig farms in Jiangsu China. Susceptibility testing was identified by micro-dilution method. PCR assay and nucleotide sequencing were used to detect COL-resistant genes, -1 to -5, as well as ESBL genes, , and . Conjugation experiment, plasmid replicon typing of the multidrug resistance (MDR), S1-PFGE and DNA southern hybridization were performed to study the transferability of these genes.
Overall, 275 isolates were recovered from a total of 432 cloacal and nasal swabs. More than 90% of the isolates were MDR, of which 70.18% were resistant to COL. Of these 275 isolates, was identified as the most predominant gene carried by 71.63% (197/275) of isolates, 39.59% (78/197) of the isolates were harboring both and ESBL genes ( and ). ESBL genotyping showed that was the most predominant ESBL (68.49%) followed by (16.4%) and (15%). Sequencing revealed that the most common variants of identified were, (69%), (29%) and (1.8%). IncHI2, IncFIB, IncFIC, IncN and IncX4 were found to be the most common Inc-types found both in donors and in transconjugants and were associated with the transfer of the and ESBL encoding genes. Six strains carried a total of five different plasmids: approximately 97-, 130-, 160-, 227- and 242-kb plasmids.
The coexistence of the and -carrying isolates displaying high MDR, recovered from of pig origin, is a major concern for both humans and veterinary medicine.
可移动的黏菌素（COL）耐药基因与超广谱β-内酰胺酶（ESBL）基因共存已在全球范围内构成严重威胁。本研究旨在调查中国养猪场中分离出的菌株对COL耐药性的增加情况，尤其是其与产ESBL菌株的共存情况。
从中国江苏的14个养猪场分离菌株。采用微量稀释法进行药敏试验。用PCR检测和核苷酸测序来检测COL耐药基因mcr -1至mcr -5以及ESBL基因blaCTX-M、blaTEM、blaSHV和blaOXA。进行接合试验、多药耐药（MDR）的质粒复制子分型、S1-PFGE和DNA Southern杂交以研究这些基因的可转移性。
总体而言，从总共432份泄殖腔和鼻拭子中分离出275株菌株。超过90%的分离株为MDR，其中70.18%对COL耐药。在这275株分离株中，mcr -1被确定为最主要携带的基因，71.63%（197/275）的分离株携带该基因，39.59%（78/197）的分离株同时携带mcr -1和ESBL基因（blaCTX-M和blaTEM）。ESBL基因分型显示blaCTX-M是最主要的ESBL（68.49%），其次是blaTEM（16.4%）和blaSHV（15%）。测序显示，鉴定出的mcr -1最常见变体为mcr -1.1（69%）、mcr -1.2（29%）和mcr -1.3（1.8%）。发现IncHI2、IncFIB、IncFIC、IncN和IncX4是供体菌和接合子中最常见的Inc类型，且与mcr -1和ESBL编码基因的转移有关。六株菌株共携带五种不同质粒：约97、130、160、227和242 kb的质粒。
从猪源分离出的携带mcr -1和ESBL的菌株共存且表现出高度MDR，这对人类医学和兽医学来说都是一个主要问题。
