Phenotypic characterization of intestinal Escherichia coli of pigs during suckling, postweaning, and fattening periods

Abstract

A highly discriminatory and standardized biochemical fingerprinting method was used to monitor the persistence and colonization of intestinal Escherichia coli isolated from the feces of four sows and their litters (four piglets from each) during the suckling, postweaning, and fattening periods. Altogether, 195 fecal samples were collected and 1,827 E. coli strains were tested (mean number of isolates tested per fecal sample per pig, 9.5). Strains were divided into similarity groups on the basis of their biochemical phenotypes (BPTs). The diversity of E. coli strains in each sample was measured with Simpson's index of diversity, and similarity between E. coli floras of piglets was calculated with a population similarity index. Each fecal sample contained several BPTs of E. coli, some of which dominated that population. The intestinal colonization of piglets consisted of successive waves of different E. coli BPTs, the tenure of which varied from a few days to 2 weeks. Most of these BPTs disappeared in the succeeding samples and were not recovered again from the same piglets. On the other hand, some E. coli strains which colonized piglets early during the suckling period persisted for a long period and were referred to as resident BPTs. Each piglet carried more than one resident BPT (mean of 2.4 BPTs per pig), some of which were also found in other piglets. This finding indicates that both strain and host specificity are important for colonization and persistence of E. coli in pigs. During the first week of life, E. coli floras of piglets were quite different from those of their dams, suggesting that the dominant E. coli strains in piglets might be quite different from those of their sow. Despite the similarity in E. coli floras between littermates during suckling, each piglet developed a unique flora during postweaning and fattening periods. Pigs which were kept together in one litter until the end of the study had E. coli floras more similar to each other than those mixed with other pigs.

ExPEC‐typical virulence‐associated genes correlate with successful colonization by intestinal E. coli in a small piglet group

“…In conclusion, we confirmed high dynamical and individual E. coli populations in pigs as already shown by other authors (Katouli et al, 1995). Even tiny changes of the intestinal milieu might force the different growth kinetics of single clones.…”

“…However, as we found similar mucosa-adherent and non-adherent E. coli populations in the porcine colon in a previous study, we assume that E. coli populations of rectal samples roughly reflect colonic colonization (Schierack et al, 2007). As the Enterobacteriaceae flora of pigs is very individual, additional slaughtered pigs would also not help to describe colonization of other living individuals (Katouli et al, 1995;Schierack et al, 2007). In our study, a higher number of ExPEC-typical VAGs correlated with a better colonization success of the respective clones in the fast developing intestine of young piglets and the presence of high numbers of VAGs supported colonization under severely differing milieus as seen for clones which were isolated before as well as after weaning.…”

“…Commensal E. coli is a member of the gastrointestinal autochthonous flora of most mammalian hosts (Gordon and Lee, 1999). Intestinal porcine E. coli populations have been described as being highly individual and dynamical (Katouli et al, 1995). Diet, climate, age, sex and weaning are thought to be responsible for changes or differences in E. coli populations (Duriez et al, 2001;Franklin et al, 2002;Gordon and Cowling, 2003;Gordon et al, 2005).…”

Determination of Vibrio scophthalmi and its phenotypic diversity in turbot larvae

“…This may indicate that the strains that remain during a certain period of time might have certain characteristics that allow them to colonize the intestine and maintain their population more easily than others. A similar situation has also been described in Escherichia coli strains from the intestinal microbiota of other animals and children (Kühn et al, 1986;Katouli et al, 1995).…”

“…This was probably a result of the fact that there are many factors (nutrition, temperature, water flux, water conditions) affecting the microbiota. The influence of nutritional factors in the alteration of the composition of the intestinal microbiota is well documented in reared fish (Gatesoupe, 1994;Ringø et al, 1995;Blanch et al, 1997), as well as in other animals (Katouli et al, 1995).…”