Multilocus sequence typing schemes for the emerging swine pathogen Mycoplasma hyosynoviae.

Mycoplasma (M.) hyosynoviae is a commensal of the upper respiratory tract in swine, which has the potential to spread systemically, usually resulting in arthritis in fattening pigs and gilts. To date, very little is known about the epidemiology of M. hyosynoviae, mainly due to a lack of suitable typing methods. Therefore, this study aimed to develop both a conventional multi locus sequence typing (MLST) and a core genome (cg) MLST scheme. The development of the cgMLST was based on whole genome sequences of 64 strains isolated from pigs and wild boars during routine diagnostics as well as nine publicly available genomes. A cgMLST scheme containing 390 target genes was established using the Ridom© SeqSphere+ software. Using this scheme as a foundation, seven housekeeping genes were selected for conventional MLST based on their capability to reflect genome wide relatedness and subsequently, all 73 strains were typed by applying both methods. Core genome MLST results revealed a high diversity of the studied strain population and less than 100 allele differences between epidemiologically unrelated strains were only detected for four isolates from the US. On the other hand, seven clonal clusters (≤ 12 allele differences) comprising 20 isolates were identified. Comparison of the two typing methods resulted in highly congruent phylogenetic trees and an Adjusted Rand Coefficient of 0.893, while cgMLST showed marginally higher resolution when comparing closely related isolates, indicated by a slightly higher Simpson's ID (0.992) than conventional MLST (Simpson's ID = 0.990). Overall, both methods seem well suited for epidemiological analyses for scientific as well as diagnostic purposes. While MLST is faster and cheaper, cgMLST can be used to further differentiate closely related isolates.

Rye and Rye Bran as Components of Diets in Piglet Production-Effects on Salmonella Prevalence.

The nutritional benefits of rye (and therefore rye bran) are mainly due to its high content of fermentable dietary fiber, the non-starch polysaccharides (NSP). Microorganisms in the large intestine are able to convert these into short-chain fatty acids (SCFA), including butyrate. Butyrate strengthens the epithelial barrier function in the colon by nourishing the enterocytes and inhibiting the spread of Salmonella in the intestinal tract. Therefore, the aim of this study was to test under field conditions whether a diet with rye or rye bran as the main ingredient for gilts, sows, and weaned piglets is associated with a lower Salmonella prevalence. Depending on the age groups, between 20-30% rye or between 15-20% rye bran was used in the experimental group. A total of n = 1983 boot swabs, n = 356 fecal samples, and n = 1909 serum samples were examined. The results of this study show that rye or rye bran at the levels used had no apparent effect on the number of positive Salmonella samples. However, the Salmonella OD values in the experimental groups were significantly lower than in the control group. This suggests that the use of rye leads to a lower incidence of infection, but this effect could not be proven from swabs.

Epidemiological Study on Salmonella Prevalence in Sow Herds Using Direct and Indirect Detection Methods.

In piglet production, the beginning of pork production, Salmonella prevalence requires greater attention as having an impact on the subsequent production steps. The aim of this study was to investigate Salmonella prevalence in three sow herds with attached piglet rearing units. Salmonella prevalence was investigated either directly by boot swabs and feces or indirectly by serum samples taken during gilt integration, the peripartal period, and piglet rearing. Boot swabs and feces were analyzed by real-time PCR and subsequent microbiology. Results indicated that high biosecurity measures in sow husbandry do not necessarily result in a low Salmonella prevalence. Furthermore, the sow herds' Salmonella prevalence should not be used to infer the situation in the associated piglet rearing. The proportion of positive boot swabs was 10.5, 3.6, and 21.3% for sows (gilts and peripartal) with an inverse situation in piglet rearing with 50.0, 63.3, and 5.8% positive swabs for farms A, B, and C, respectively. Boot swabs are suitable as a direct sampling method to gain an overview of Salmonella prevalence in both sows and piglets. Indirect serum antibody testing can be useful, although it should be evaluated considering age-dependent levels of antibody titres.

[Cure rates of chronic subclinical Staphylococcus aureus mastitis in lactating dairy cows after antibiotic therapy]. / Heilungsraten chronischer subklinischer Staphylococcus aureus-Mastitiden nach antibiotischer Therapie bei laktierenden Milchkühen.

Staphylococcus (S.) aureus is an important mastitis causing pathogen in dairy cows worldwide. The aim of this controlled and randomized study was to analyze the effects of an antibiotic treatment on chronic subclinical S.aureus mastitis during lactation.The study was conducted between July 2011 and December 2011 in Northern Germany including 134 udder quarters (i. e. 103 dairy cows) infected with S. aureus. The animals were randomly divided into two groups (control and treatment group). Quarter foremilk duplicate samples were taken on days 0, 7, 32 and 39 from each infected udder quarter for microbiological analysis and somatic cell count determination. Treatment consisted of cephalexin (200 mg intramammarily 5 times every 12 h) plus marbofloxacine (2 mg/kg BM subcutaneously 3 times every 24 h). "Pathogen elimination" was assessed as the status, when no S. aureus was isolated from the quarter samples of days 32 and 39. "Cure" was defined as the status, when in addition to pathogen elimination the somatic cell count of the quarter in both milk samples was below 100 000/ml. Animals of the treatment group showed a pathogen elimination rate of 35.9% and a cure rate of 21.9%. The rates for the control group were 21.4% and 8.6%, resp. The differences between groups were statistically significant. These results indicate that pathogen elimination and cure rates of chronic subclinical S. aureus mastitis are low after an intramammary cephalexin and subcutaneous marbofloxacine treatment, but still significantly better than without any antibiotic treatment.