The aim of this study was to determine the prevalence of fecal ESBL-producing Escherichia coli (E. coli) in pigs on large and small farms in Latvia, to characterize beta-lactamase genes and establish an antimicrobial resistance profile. Fecal samples (n = 615) were collected from 4-week, 5-week, 6-week, 8-week, 12-week and 20-week-old piglets, pigs and sows on four large farms (L1, L2, L3, L4) and three small farms (S1, S2, S3) in Latvia. ChromArt ESBL agar and combination disc tests were used for the screening and confirmation of ESBL-producing E. coli. The antimicrobial resistance was determined by the disc diffusion method and ESBL genes were determined by polymerase chain reaction (PCR). Subsequently, ESBL-producing E. coli was confirmed on three large farms, L1 (64.3%), L2 (29.9%), L3 (10.7%) and one small farm, S1 (47.5%); n = 144 (23.4%). The prevalence of ESBL-producing E. coli differed considerably between the large and small farm groups (26.9% vs. 12.7%). Of ESBL E. coli isolates, 96% were multidrug-resistant (MDR), demonstrating there were more extensive MDR phenotypes on large farms. The distribution of ESBL genes was bla_TEM (94%), bla_CTX-M (94%) and bla_SHV (48%). On the small farm, bla_SHV dominated, thus demonstrating a positive association with resistance to amoxicillin-clavulanic acid, ceftazidime and cefixime, while on the large farms, bla_CTX-M with a positive association to cephalexin and several non-beta lactam antibiotics dominated. The results indicated the prevalence of a broad variety of ESBL-producing E. coli among the small and large farms, putting the larger farms at a higher risk. Individual monitoring of ESBL and their antimicrobial resistance could be an important step in revealing hazardous MDR ESBL-producing E. coli strains and reviewing the management of antibiotic use.

中文翻译：

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拉脱维亚不同规模农场猪的粪便产超广谱β-内酰胺酶大肠杆菌的流行率和特征

本研究的目的是确定拉脱维亚大型和小型农场猪的粪便产 ESBL大肠杆菌( E.coli )的流行情况，以表征 β-内酰胺酶基因并建立抗菌素耐药性概况。粪便样本 (n = 615) 从四个大农场 (L1、L2、L3 , L4) 和拉脱维亚的三个小农场 (S1, S2, S3)。ChromArt ESBL 琼脂和组合圆盘测试用于筛选和确认产 ESBL大肠杆菌。抗菌素耐药性由圆盘扩散法测定，ESBL 基因由聚合酶链反应 (PCR) 测定。随后，产生 ESBL 的E .在三个大型农场 L1 (64.3%)、L2 (29.9%)、L3 (10.7%) 和一个小型农场 S1 (47.5%) 中确认了大肠杆菌；n = 144 (23.4%)。大农场和小农场之间产 ESBL大肠杆菌的流行率差异很大（26.9% 对 12.7%）。ESBL大肠杆菌分离株中，96% 具有多重耐药性 (MDR)，这表明大型农场存在更广泛的 MDR 表型。ESBL 基因的分布为bla _TEM (94%)、  bla _CTX-M (94%) 和bla _SHV (48%)。在小农场，bla _SHV占主导地位，因此表明与对阿莫西林-克拉维酸、头孢他啶和头孢克肟的耐药性呈正相关，而在大型农场，bla _CTX-M与头孢氨苄和几种非β内酰胺抗生素呈正相关。结果表明，在小型和大型农场中广泛存在产 ESBL 的大肠杆菌，使较大的农场面临更高的风险。对 ESBL 及其抗菌素耐药性的个体监测可能是揭示危险的 MDR ESBL 产生大肠杆菌菌株和审查抗生素使用管理的重要一步。