The role of bacterial pathogens in coliform mastitis in sows.

Even in modern piglet production, mastitis and lactation failure in sows represent a considerable health problem post partum, affecting in its consequences both the sow and her piglets. Known as a multifactorial syndrome, Mastitis-Metritis-Agalactia (MMA) has been topic of several studies investigating possible influencing factors at farm and sow level in the recent past. However, there is a lack of current investigations on the causative pathogens, especially with advanced laboratory methods and with an adequate control group of healthy animals. Therefore, 1026 milk samples from coliform mastitis (CM)-affected, and 972 samples from healthy sows on six farms were examined bacteriologically in this study. The spectrum of isolated bacteria did not differ significantly between diseased and healthy animals for most species, with Escherichia coli as predominant species with 70.4% positive samples from diseased, and 78.0% positive samples from healthy animals. Furthermore, other Enterobacteriaceae, Staphylococcaceae, Streptococcaceae and Enterococcaceae were isolated both from CM-affected and non-affected animals.The similar bacteria distribution underlines the multifactorial pathogenesis of CM: Only with further adverse--endogen or exogen--factors being present, ubiquitous bacteria from the sow's environment can contribute to the development of clinical signs of infection.

Comparison of virulence gene profiles of Escherichia coli isolates from sows with coliform mastitis and healthy sows.

Coliform mastitis (CM) is not only a serious economical and animal welfare touching problem in dairy cattle, but also in sows after farrowing. Due to this disease, the essential adequate supply with colostrum for the growth and the health of the piglets is not ensured. Besides other influencing factors, Escherichia (E.) coli is of great importance as a causative agent of this multifactorial disease. In this study, E. coli isolates from milk samples of healthy and CM-affected sows were examined for the presence of virulence genes associated with extraintestinal E. coli strains, enterotoxigenic E. coli and other pathogenic E. coli. The isolated E. coli harbored mainly virulence genes of extraintestinal E. coli strains (especially fimC, ompA, traT, hra, kpsMTII, iroN). The virulence gene spectrum for both samples from CM-affected and healthy sows did not differ significantly. Particular virulence gene profiles of E. coli isolates from diseased sows were not detected. This study provides novel insights into the role of E. coli in association with mastitis in sows since it is the first time E. coli isolates from CM-affected sows' milk were analysed for virulence genes. Because there were no differences in the prevalence of E. coli and their virulence-associated genes between healthy and diseased sows, other causative factors seem to have greater influence on the pathogenesis of porcine CM.

Assessing individual sow risk factors for coliform mastitis: a case-control study.

In order to investigate sow-specific risk factors associated with coliform mastitis, a case-control study was performed over the course of 28 months. Data of three farms were collected under production conditions. Sows suffering from coliform mastitis after farrowing served as cases, and healthy half- or full-sib sows from the same farm served as controls. Individual sow characteristics and the seasonal influence were analysed by conditional logistic regression. The final multivariate model identified four risk factors: the risk of suffering from coliform mastitis increased with a higher number of piglets born alive and stillborn piglets. Gilts had an increased risk for the disease, and birth intervention was also associated with a higher prevalence of mastitis. Birth induction and season had no significant influence on the occurrence of coliform mastitis. The time during and soon after farrowing is a very sensitive period in pig production demanding great attention by the farmer. With respect to the economic losses, monitoring of potentially endangered sows as well as detailed documentation and selection of disease cases are of particular importance when coping with coliform mastitis.

Bacteria in milk from anterior and posterior mammary glands in sows affected and unaffected by postpartum dysgalactia syndrome (PPDS).

BACKGROUND: The performance of piglet weight gain is strongly dependent on the sow's ability to meet the demand for adequate milk. Postparturient disorders, especially those subsumed under the term postpartum dysgalactia syndrome (PPDS), can alter or reduce the milk production sensitively, resulting in starving piglets. The aim of this study was to gather further information about the prevalence of different bacterial species in the anterior and posterior mammary glands of sows with respect to the clinical appearance of PPDS. METHODS: In this study, the health status of 56 sows after farrowing was determined with special regard to mastitis and dysgalactia. Pooled milk samples from anterior and posterior glands were taken from both affected and non-affected animals and analysed bacteriologically for the presence of a wide spectrum of different pathogens. RESULTS: Mainly Escherichia coli, staphylococci and streptococci were detected in high percentages but without significant differences in healthy and diseased animals and anterior and posterior glands. However, the large percentages of coliform bacteria suggested a transmission route via faecal contamination. CONCLUSION: In this study, the prevalence of different bacteria in anterior and posterior glands in PPDS positive and negative sows was analysed. No significant differences in bacteria of healthy and diseased sows were assessed. Therefore, the development of clinical PPDS and actual infection seems to be largely dependant on individual resistance in single sows.