High prevalence of F4+ and F18+ Escherichia coli in Cuban piggeries as determined by serological survey

Abstract

Little information is available on the prevalence of swine enteropathogens in Cuba where diarrheic diseases are responsible for 31% and 37% of the total mortality during the neonatal and postweaning periods. F4 + and F18 + enterotoxigenic Escherichia coli and F18 + verotoxigenic E. coli induce diarrhea and edematous disease in pigs, but their distribution has never been thoroughly studied in the Cuban swine population. Therefore, the present study estimated the prevalence of F4-and F18-specific antibodies in sera of 1,044 6-month-old gilts distributed in 34 piggeries spread over the Cuban territory. For the data analysis, which included the optical density of individual samples tested by ELISA, random-effects models and a mixture model in R (package "mixAK"; Komárek, Computational Statistics and Data Analysis 53:3932-3947, 2009) were fitted. Low, moderate, and high levels of F4-specific antibodies were found in 67.6%, 26.8%, and 5.6% of the gilts, while 66.4% and 33.6% of gilts showed low and high levels of F18-specific antibodies. Hereby, we show that F4 + and F18 + E. coli are highly prevalent as potential enteropathogens in Cuban piggeries.

A Tripartite Fusion, FaeG-FedF-LT192A2:B, of Enterotoxigenic Escherichia coli (ETEC) Elicits Antibodies That Neutralize Cholera Toxin, Inhibit Adherence of K88 (F4) and F18 Fimbriae, and Protect Pigs against K88ac/Heat-Labile Toxin Infection

“…Moreover, two control piglets died within 18 h postinoculation. When the ileum segments of the small intestines were used for quantitative colonization assays, we found that the immunized piglets had 3.16 Ϯ 2.62 (ϫ10 8 ) CFU of 3030-2 bacteria colonized per gram of ileal tissue, which was significantly lower than the level of colonization in the control piglets (15.83 Ϯ 6.38 [ϫ10 8 ] CFU per gram of ileum) (P Ͻ 0.01). In addition, the total amounts of plasma proteins detected in blood samples of the control piglets after challenge were significantly greater (P Ͻ 0.01) than those in the blood samples collected before oral inoculation, suggesting that dehydration occurred in the control piglets after being challenged with the ETEC strain.…”

“…FaeG-FedF-LT 192 A2:B ELICITS ANTIADHESIN AND ANTITOXIN Abs 1597 causing postweaning diarrhea express K88 or F18 adhesin and LT and/or ST toxins (6,8,9,16,22,37,44 ). However, this K88ac/LT 192 -STb strain is not expected to protect weaned pigs against F18 ETEC strains, as it does not induce cross-protective anti-F18 immunity.…”

“…However, when the conserved F18 minor fimbrial subunit FedF was produced as a fusion protein with maltose-binding protein (MBP) and conjugated to K88 fimbriae, protective anti-F18 immunity was induced (29). Therefore, it was suggested that the FedF antigen should be conjugated with K88 fimbriae for developing vaccines against porcine ETEC postweaning diarrhea (8,29). Data from the current study showed that genetic fusion of the FedF peptide with the K88 FaeG major subunit (and LT 192 A2:B) induced antibodies inhibiting F18 fimbrial adherence.…”

“…Fimbriae expressed by ETEC strains isolated from young pigs with diarrhea include K88 (F4), F18, K99 (F5), 987P (F6), and F41 (F7), and toxins produced by porcine ETEC strains are heat-labile (LT), heat-stable type I (STa), heat-stable toxin type II (STb), Shiga toxin 2e (Stx2e), and enteroaggregative heatstable toxin 1 (EAST1) (9,44). ETEC strains expressing K88 or F18 fimbriae and LT and ST (STa and STb) toxins are the most commonly associated with diarrhea in weaned pigs (8,9,22,44). In the United States, nearly all porcine postweaning diarrhea cases are associated with ETEC strains expressing K88 or F18 fimbria with one or more toxins (44).…”

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.…”