Studies on Escherichia coli in Pigs II. Serological Investigations1)

Abstract

Summary 957 strains of E. coli isolated from 294 pigs in 149 herds were investigated serologically. The antigenic analysis was mainly concerned with the definition of the O antigen and, to a certain extent, with the K antigen. More than 60% of all the strains investigated belonged to one of the O‐groups 8, 138, 139, 141, 147, and 149. The serological findings were compared with the clinical and autopsy diagnoses. The material was divided into pigs with enteritis confirmed by autopsy findings (material A) and pigs with autopsy findings other than enteriis (material B). There was no significant difference in the frequency of the above‐mentoined O‐groups between materials A and B in age‐groups I, III and IV; in age‐group II the frequency was higher in material A than in material B. In newborn and suckling piglets with enteritis, O‐groups 8, 141, and 147 were most often isolated. In weanling pigs with enteritis, O‐group 141 was most frequent, and in the pigs between approx. 10 weeks and 4 months old with enteritis, O‐groups 138 and 141 were most common. Pure cultures of E. coli were isolated from the intestinal tract and other internal organs in 21%, whereas the autopsy findings pointed to septicaemia in only 3%. Zusammenfassung Untersuchungen an E. coli aus Schweinen II. Serologische Prüfungen 957 Stämme von E. coli, welche von 294 Schweinen aus 149 Herden isoliert worden waren, wurden serologisch untersucht. Die Antigenanalysen konzentrierten sich hauptsächlich bis auf wenige Ausnahmen, wobei auch das K‐Antigen nachgewiesen wurde, auf die Bestimmung des O‐Antigens. Mehr als 60% der geprüften Stämme gehörten den O‐Gruppen 8, 138, 139, 141, 147 und 149 an. Die serologischen Ergebnisse wurden verglichen mit der klinischen Diagnose und den Autopsie‐Befunden. Das Material wurde unterteilt nach Schweinen mit pathologisch verifizierter Enteritis (Material A) und Schweinen mit anderen pathologischen Befunden (Material B). Es wurde dabei keine signifikante Differenz in der Häufigkeit der oben angeführten O‐Gruppen in Material A und B bei den Altersgruppen I, III und IV festgestellt. Bei Altersgruppe II waren sie in Material A stärker als in Material B vertreten. Bei Neugeborenen und bei Saugferkeln mit Enteritis wurden die O‐Gruppen 8, 141 und 147 am meisten isoliert. Bei Absetzferkeln mit Enteritis war die O‐Gruppe 141 am häufigsten vertreten und bei Schweinen in einem Alter von ungefähr zehn Wochen bis zu vier Monaten mit Enteritis dominierten E. coli den O‐Gruppen 138 und 141. Reinkulturen von E. coli wurden isoliert aus dem Verdauungstrakt und aus anderen inneren Organen in 21% der Fälle, während die Autopsie gleichzeitig nur bei 3% Septikaemie ergab. Résumé Recherches sur Escherichia coli chez les porcs II. Examens sérologiques On examine sérologiquement 957 souches de E. coli, isolées chez 294 porcs de 149 troupeaux. Les analyses antigéniques se concentrent principalement sur la détermination de l'antigène O, à part quelques exceptions où l'on a mis également en évidence l'antigène K. Plus de 60% des souches testées a...

Studies on Escherichia coli in Pigs

“…Another explanation might be that the wrong E. coli colonies were investigated from the piglets. Only one strain was investigated from each piglet, both for practical reasons and because it had been earlier shown (SODERLIND, 1971 b) that the pathogenic strains of E. coli in coli-induced piglet diarrhoea usually strongly dominate the aerobic flora of the intestine. An expanded study of 10 strains from each piglet was performed after this study and will be reported separately (SODERLIND and MOLLBY, to be published).…”

“…From each pig one representative E. coli strain was chosen for further investigation. E. coli-like colonies were examined biochemically by the following tests at 37 ('C: gas from glucose, urease, Voges-Proskauer and growth in SIMMONS' ammonium-citrate medium, fermentation of rhamnose, lactose, maltose, sucrose, adonitol and inositol (SODERLIND, 1971 a).…”

“…Immune sera for 0 antigens and K 88 antigen were prepared by the technique described in previous investigations (SODERLIND, 1971 b). Tube agglutination tests were carried out with 13 sera belonging to 0 groups 2, 6, 8, 9, 32, 45, 64, 138, 139, 141, 147, 149, and 157.…”

Phenotyping of E. coli serotypes associated to oedema disease

“…After incubation at 37°C for 18h, at least two colonies were cultivated in a beef extract broth (NVI product 311060) at 37°C for another 18h. The broth culture was then heated in 100°C for 1 hour and agglutinated with specific antisera from a panel of different E. coli serotypes [ 26 ]. This panel of serotypes is continuously updated in order to represent the most common pathogenic strains of E. coli in Sweden [ 29 , 27 ].…”

“…For diseases caused by a limited number of serotypes of E. coli , such as oedema disease, serotyping is a valuable diagnostic tool [ 25 ], and Sweden has a long tradition of serotyping E. coli collected from young pigs affected by intestinal disorders, including oedema disease [ 26 , 27 ]. Aiming to increase the information even furhter, all strains associated to oedema disease (O138, O139 and O141) collected during the period 1994–98 were phenotyped with a biochemical finger printing system [ 28 ] and comparisons were made within serotypes.…”