Prevalence of Clostridium difficile in diarrhoeic and non-diarrhoeic piglets

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Abstract

Clostridium difficile is considered to be an important causative agent of porcine neonatal diarrhoea, having taken over from classic bacterial pathogens. However, there are currently no clear data concerning the prevalence of this microorganism in piglets, or about its relative distributions among diarrhoeic and non-diarrhoeic animals. In the present study, we analyzed the presence of C. difficile in rectal swabs from 780 piglets from two age groups (newborn and 1–2-month-old pigs) by means of molecular and microbiological procedures. Furthermore DNA was isolated from the bacteria in order to identify toxin A and toxin B genes.C. difficile was not found in any of the 239 samples taken from 1- to 2-month-old pigs. Bacteria were, however, recovered from 140 out of 541 newborn piglets (25.9%), including both diarrhoeic and non-diarrhoeic animals, and animals from control farms (free of diarrhoeic animals). Genes for the production of both toxins A and B were identified in 132 of the 140 isolates (A+B+). Only seven isolates, all from the same farm and from non-diarrhoeic animals, lacked both toxin genes (AB), while one isolate from this same group of animals was AB+.This study provides the first report comparing the prevalence of C. difficile in large numbers of diarrhoeic and non-diarrhoeic animals. There was no clear link between bacterial isolation and neonatal porcine diarrhoea.

Introduction

Clostridium difficile is a ubiquitous bacterium in the environment and has been recognised as an important emerging pathogen in both humans and animals. C. difficile is also the most important cause of antimicrobial- associated and hospital-associated diarrhoea in humans. In recent years, an increase in the incidence of human C. difficile infections has been reported, as well as an increase in the virulence and antimicrobial resistance of the isolates (Pepin et al., 2004, McDonald et al., 2005, Kuijper et al., 2006, Jhung et al., 2008).

Veterinary medicine has highlighted the role of animals as reservoirs for C. difficile, as well as its zoonotic implications and its pathogenicity in different animal species, mainly in equids and swine (Borriello et al., 1983, Arroyo et al., 2005, Rodriguez-Palacios et al., 2006, Rupnik, 2007). The importance of C. difficile as an agent involved in porcine neonatal diarrhoea has increased, displacing classic bacterial pathogens (Songer et al., 2000, Yaeger et al., 2002, Songer and Uzal, 2005). However, some questions remain to be answered, such as the role of toxins in the pathogenesis of the microorganism and the susceptibility of swine to C. difficile colonization (Waters et al., 1998, Songer, 2004, Songer and Anderson, 2006).

In spite of the importance of C. difficile as a swine pathogen, there are currently no clear data concerning the prevalence of this microorganism in pig farms in relation to age, or its relative prevalence in animals with and without diarrhoea.

The aims of this study were to analyse the prevalence of C. difficile in two age groups of diarrhoeic and non-diarrhoeic pigs (newborn pigs (1–7 days old) and 1–2-month-old pigs), and to determine the presence of C. difficile toxin A and toxin B genes in the isolates.

Section snippets

Samples

Rectal swabs were obtained from 780 animals: 541 from 1- to 7-day-old piglets (287 non-diarrhoeic and 254 diarrhoeic animals) and 239 from 1- to 2-month-old pigs (187 non-diarrhoeic and 52 diarrhoeic animals). Samples came from 13 pig farms located in three densely swine populated areas in Spain, located in three different Autonomous Communities (zone A [Aragon], zone B [Catalonia] and zone C [Castile-La Mancha]).

A total of 13 herds was sampled: 10 had experienced continuous problems with

Results

The results of C. difficile isolation from 1- to 7-day-old piglet faecal samples are shown in Table 1. Table 1 also shows the results of the PCR detection of C. difficile tcdA and tcdB genes. C. difficile was recovered from 140 out of 541 (25.9%) rectal swabs taken from 1- to 7-day-old piglets. Moreover, C. difficile was isolated from at least one non-diarrhoeic piglet from this age group from all the sampled farms, including the control farms. Conversely, at one farm (C2), C. difficile was not

Discussion

In the present work, C. difficile was not isolated from any 1–2-month-old pig. However, this bacterium was recovered from a considerable proportion of 1–7-day-old piglets, regardless of the presence or absence of diarrhoea. Moreover, differences in C. difficile prevalence in piglets were observed among the three production areas sampled, though significant differences were only found between zone B and other zones, or the control farms.

It has been suggested that C. difficile may be currently

Conflict of interest statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Acknowledgements

This work was partially supported by grant FAU2006-00005-C02 INIA from the Spanish Ministry of Education and Science. This work was partially supported by LABORATORIOS HIPRA, S.A. Sergio Álvarez-Pérez acknowledges a grant from the FPU programme (ref. AP 2005-1034), Spanish Ministry of Education and Science.

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