Prevalence of virulence genes in Escherichia coli strains isolated from piglets in the suckling and weaning period in Mexico

Abstract

Faecal Escherichia coli isolates from suckling (n5503) and weaning (n5450) piglets with and without diarrhoea from 10 farms in Mexico were examined for identification and prevalence of virulence genes. E. coli isolates were tested further for enterotoxin (LT, STa, STb, Stx1, Stx2 and EAST1), fimbrial (F4, F5, F6, F17, F18 and F41) and eae adhesin genes by multiplex PCR. Of the 953 isolates of E. coli examined by multiplex PCR, 650 (68.2 %) isolates were positive for at least one adhesin gene. Among the isolates from diarrhoeic piglets, F41 (72 %) was the most prevalent adhesin followed by eae adhesin (27 %), F6 (12 %), F17 (9 %), F18 (9 %), F5 (8 %) and F4 (3 %). Enterotoxin genes were detected in 424 (44.5 %) of the isolates, of which EAST1 (38 %) and STa (30 %) were the most common, followed by STb (17 %), Stx2 (6 %) and LT (5 %). Twenty-three per cent of isolates from suckling piglets and 43 % of isolates from weaned piglets carried both enterotoxin and adhesin genes, the most common virotypes being F41 : STa, F41 : EAST1, EAST1 : eae, F41 : F6, F41 : STa : STb, F41 : eae and F17 : eae. The present study examined for the first time, to our knowledge, the prevalence of 13 virulence genes among E. coli strains isolated from piglets with and without diarrhoea in Mexico. The results suggested that there are a wide variety of virulence genes associated with diarrhoea in piglets. This study provides baseline information on the significance of specific virotypes associated with suckling and weaning periods in piglets in Mexico.

Aetiologically Relevant Typing of E. Coli Isolates from Diseased Pigs in Switzerland during 2014 and 2015

“…46 out of 52 ETEC isolates harboured the STb gene in combination with other enterotoxins. These findings substantiate other studies, where STb was the most frequently detected enterotoxin and often occurred in ETEC isolates in combination with other enterotoxins [3,4], except the study of Toledo et al [12], where the gene for STa was the most common enterotoxin.…”

“…These findings agree with other studies from different countries [4,5], where the fimbrial gene for F4 was one of the most frequent genes found in piglets suffering from diarrhoea. In contrast, a study from Mexico and China provided other results, indicating that the presence of virulence genes in E. coli varies with the geographical area [12,13]. The serogroup O149:K91 was clearly correlated with the F4 fimbrial gene, and contrarily O141:K85 was correlated with the F18 fimbrial gene.…”

Enterotoxigenic Escherichia coli strains are highly prevalent in Ugandan piggeries but disease outbreaks are masked by antibiotic prophylaxis

“…However, the epidemiology of infections remain largely unknown, and only limited recent reports on prevalences and characteristics of pathogenic strains from a few countries exist (Zhang et al 2007;Madoroba et al 2009;de la Fé Rodríguez et al 2011;Toledo et al 2012;Mohlatlole et al 2013;Liu et al 2014). Moreover, most farmers use antibiotic prophylaxis as a management strategy, a practice banned in Europe (Casewell, et al 2003) due to public health concern.…”

Prevalence and characterization of virulence genes in Escherichia coli isolated from piglets suffering post‐weaning diarrhoea in Shandong Province, China

“…In addition, ETEC can produce enterotoxins, including heat‐labile (LT‐I and LT‐II) and heat‐stable (STa and STb), to destroy fluid homoeostasis in the intestine leading to diarrhoea (Liu et al, ; Luppi et al, ). Many investigations demonstrated that enteroaggregative E. coli heat‐stable enterotoxin 1 (EAST1) is frequently detected among pathogenic E. coli isolates from humans and animals with diarrhoea (Liu et al, ; Toledo et al, ; Vu‐Khac et al, ; Zhang et al, ).…”