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

Abstract

The present study was performed to investigate the prevalence and characteristics of virulence genes in Escherichia coli (E. coli) isolated from piglets suffering post‐weaning diarrhoea (PWD) in Shandong Province, China. The standard bacteriological method was used to isolate and identify E. coli, and then multiplex polymerase chain reaction (mPCR) was performed to determine virulence genes in E. coli. Among the 300 isolates, 166 (55.3％) harboured at least one virulence gene. Among the 166 isolates, 155 (93.4％) contained toxin‐related genes. For enterotoxin genes, EAST1 (58/166, 34.9％) and LT‐I (45/166, 27.1％) were the most common, followed by STa (32/166, 19.3％) and STb (21/166, 12.7％); for pathogenicity island (PAI) genes, irp2 (49/166, 29.5％) was the most dominant, followed by eae (48/166, 28.9％); for Shiga toxigenic E. coli (STEC)‐associated toxin genes, Stx2e and hlyA genes were observed in 19 (19/166, 11.4％) and three strains (3/166, 1.8％) respectively. In addition, of the 166 isolates, 95 (95/166, 57.2％) contained adhesin genes, and AIDA‐I (33/166, 19.9％) was the most common, followed by paa (27/166, 16.3％), F5 (K99) (20/166, 12.0％), F18 (15/166, 9.0％) and F41 (12/166, 7.2％). In summary, these findings demonstrated the prevalence and characteristics of virulence factors in E. coli isolates from piglets with PWD in Shandong Province of China, and the data may be useful for establishing preventive measures for post‐weaning piglet diarrhoea.

A multivalent vaccine candidate targeting enterotoxigenic Escherichia coli fimbriae for broadly protecting against porcine post-weaning diarrhea

“…This lack of cross-protection is because there is no cross-reactivity between K88, K99, 987P, F18, and F41 fimbriae. Though the predominant fimbrial types of ETEC isolated associated with cases of PWD are K88 and F18 fimbriae, K99, 987P, and F41 fimbriae have also been detected with different rates in different regions [4,6,7]. Therefore, each of these fimbria types needs to be included in the vaccine to allow for the broadest level of protection.…”

“…Molecular epidemiological studies, from cases of calibacillosis in pigs, have indicated that post-weaning diarrhea (PWD) is primarily caused by ETEC strains expressing K88 and F18 fimbriae, with the K88ac variant of the K88 fimbria being the most prevalent [4,5]. Although K99, 987P, and F41 fimbriae are usually associated with neonatal diarrhea, they are occasionally found in PWD infections [4,6,7]. Despite the difference in the antigenic classification of K88 serological variants (e.g., K88ab, ac, ad), the major structural subunit-FaeG-has been recognized as the common adhesive subunit to all variants [8].…”

“…Luppi et al [6] reported that the prevalence rate of K99, 987P and F41 fimbriae among ETEC isolated from cases of PWD was 0.6%, 0.6% and 0.3%, respectively in Europe. In China, F5 (12%), F6 (7.2%) and F41 (6%) were also frequently detected, suggesting that these fimbriae were closely related to ETEC isolated from piglets with PWD [7]. Therefore, a vaccine that encompasses all five ETEC fimbriae would be more effective in providing holistic protection against ETEC-driven PWD.…”

A Retrospective Study of the Prevalence of Virulence Factors of Escherichia Coli Causing Postweaning Diarrhoea in Spain.

“…With respect to AIDA, a recent study carried on China showed AIDA-1 as the most prevalent adhesion factor gene (19.9%) [9]. Another study from Austria remarks the possible importance of this adhesion factor since it was detected in a high percentage of affected animals (99).…”

Effects of organic acid, Enterococcus faecalis strain EC-12 and sugar cane extract in feed against enterotoxigenic Escherichia coli-induced diarrhea in pigs

“…Post-weaning diarrhea (PWD) by enterotoxigenic Escherichia coli (ETEC) has significant economic impact on swine production worldwide (Amezcua et al 2002;Li et al 2020). ETEC that induces PWD produces heatlabile enterotoxin (LT) and/or heat-stable enterotoxin (STa, STb) and are mainly expressed in F4 or F18 fimbriae.…”