Alba Patricia, Leekitcharoenphon Pimlapas, Franco Alessia, Feltrin Fabiola, Ianzano Angela, Caprioli Andrea, Stravino Fiorentino, Hendriksen Rene S, Bortolaia Valeria, Battisti Antonio
Department of General Diagnostics, National Reference Laboratory for Antimicrobial Resistance, Istituto Zooprofilattico Sperimentale del Lazio e della Toscana, Rome, Italy.
WHO Collaborating Centre for Antimicrobial Resistance in Foodborne Pathogens and Genomics and European Union Reference Laboratory for Antimicrobial Resistance, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark.
Front Microbiol. 2018 Jun 12;9:1217. doi: 10.3389/fmicb.2018.01217. eCollection 2018.
Colistin resistance by mobilisable genes has been described in bacteria of food-animal origin worldwide, which has raised public health concerns about its potential foodborne transmission to human pathogenic bacteria. Here we provide baseline information on the molecular epidemiology of colistin-resistant, -positive and isolates in food-producing animals in Italy in 2014-2015. A total 678, 861 and 236 indicator , Extended Spectrum Beta-Lactamase (ESBL)/AmpC-producing , and isolates, respectively, were tested for colistin susceptibility. These isolates were collected according to the EU harmonized antimicrobial resistance monitoring program and are representative of at least 90 and 80% of the Italian poultry (broiler chickens and turkeys) and livestock (pigs and bovines < 12 months) production, respectively. Whole genome sequencing by Illumina technology and bioinformatics (Center for Genomic Epidemiology pipeline) were used to type 42 positive isolates by PCR. Colistin resistance was mainly observed in the ESBL/AmpC population, and was present in 25.9, 5.3, 6.5, and 3.9% of such isolates in turkeys, broilers, pigs, and bovines, respectively. Most colistin-resistant isolates (141/161, 87.5%) harbored genes of the -1 group. 1 was also detected in a small proportion of isolates (3/146, 2.0%) in turkeys. Additional types were -3 in four ESBL-producing from bovines, and two -4 in ESBL ( = 1) and indicator ( = 1) from pigs and bovines. We describe notable diversity of variants with predominance of 1.1 and 1.2 on conjugative IncX4 plasmids in and in serovars Typhimurium, Newport, Blockley from turkey. A new variant, -1.13 was detected in the chromosome in in turkey and pig isolates. Additionally, we describe -3.2 and -4.3 in from bovines, and -4.2 in from pigs. These findings elucidate the epidemiology of colistin resistance in food-producing animals in Italy along with its genetic background, and highlight the likelihood of horizontal transfer between commensal bacteria and major food-borne pathogens () within the same type of productions. Thorough action and strategies are needed in order to mitigate the risk of transfer to humans, in a "One Health" perspective.
世界各地源自食用动物的细菌中已发现可移动基因介导的黏菌素耐药性，这引发了公众对其通过食物传播给人类病原菌的潜在风险的担忧。在此，我们提供了2014 - 2015年意大利食用动物中耐黏菌素、携带mcr基因的分离株的分子流行病学基线信息。分别对总共678株指示菌、861株产超广谱β-内酰胺酶（ESBL）/AmpC酶的菌株以及236株携带mcr基因的分离株进行了黏菌素敏感性测试。这些分离株是根据欧盟统一的抗菌药物耐药性监测计划收集的，分别代表了意大利至少90%的家禽（肉鸡和火鸡）和80%的家畜（猪和12月龄以下的牛）产量。通过Illumina技术和生物信息学方法（基因组流行病学中心流程）对42株携带mcr基因的阳性分离株进行全基因组测序及分型。黏菌素耐药性主要在产ESBL/AmpC酶的菌株群体中观察到，在火鸡、肉鸡、猪和牛的此类分离株中分别占25.9%、5.3%、6.5%和3.9%。大多数耐黏菌素分离株（141/161，87.5%）携带mcr - 1基因。mcr - 2也在一小部分火鸡分离株（3/146，2.0%）中被检测到。另外，在4株来自牛的产ESBL酶的菌株中发现了mcr - 3，在来自猪和牛的1株产ESBL酶（mcr = 1）和1株指示菌（mcr = 1）中发现了2株mcr - 4。我们描述了mcr变体的显著多样性，在火鸡的鼠伤寒沙门氏菌、新港沙门氏菌、布勒克利沙门氏菌血清型中，接合型IncX4质粒上以mcr - 1.1和mcr - 1.2为主。在火鸡和猪的分离株中，在染色体上检测到一个新的变体mcr - 1.13。此外，我们描述了来自牛的菌株中的mcr - 3.2和mcr - 4.3，以及来自猪的菌株中的mcr - 4.2。这些发现阐明了意大利食用动物中黏菌素耐药性的流行病学及其遗传背景，并突出了同一生产类型中共生细菌与主要食源性病原体（沙门氏菌）之间mcr基因水平转移的可能性。从“同一健康”的角度来看，需要采取全面的行动和策略来降低mcr基因转移给人类的风险。
