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Institute
Staphylococcus aureus is recognized worldwide as one of the major agents of dairy cow intra-mammary infections. This microorganism can express a wide spectrum of pathogenic factors used to attach, colonize, invade and infect the host. The present study evaluated 120 isolates from eight different countries that were genotyped by RS-PCR and investigated for 26 different virulence factors to increase the knowledge on the circulating genetic lineages among the cow population with mastitis. New genotypes were observed for South African strains while for all the other countries new variants of existing genotypes were detected. For each country, a specific genotypic pattern was found. Among the virulence factors, fmtB, cna, clfA and leucocidins genes were the most frequent. The sea and sei genes were present in seven out of eight countries; seh showed high frequency in South American countries (Brazil, Colombia, Argentina), while sel was harboured especially in one Mediterranean country (Tunisia). The etb, seb and see genes were not detected in any of the isolates, while only two isolates were MRSA (Germany and Italy) confirming the low diffusion of methicillin resistance microorganism among bovine mastitis isolates. This work demonstrated the wide variety of S. aureus genotypes found in dairy cattle worldwide. This condition suggests that considering the region of interest might help to formulate strategies for reducing the infection spreading.
A nonblinded, positively controlled, noninferiority trial was conducted to evaluate the efficacy of an alternative, nonantibiotic therapy with Masti Veyxym® to reduce ineffective antibiotic usage in the treatment of nonsevere clinical mastitis (CM) in cows with longer lasting udder diseases. The solely intramammary treatment with Masti Veyxym® (three applications, 12 hr apart) and the combined treatment with Masti Veyxym® and antibiotics as usual on the farm according to label of the respective product were compared with the reference treatment of solely antibiotic therapy. The matched field study was conducted on eight free-stall dairy farms located in Eastern Germany. Cases of mild-to-moderate CM in cows with longer lasting high somatic cell counts in preceding dairy herd improvement test days and with previous CM cases in current lactation were randomly allocated to one of the three treatment groups. A foremilk sample of the affected quarter was taken before treatment and again approximately 14 days and 21 days after the end of therapy for cyto-bacteriological examination. Primary outcomes were clinical cure (CC) and no CM recurrence within 60 days after the end of treatment (no R60). Bacteriological cure (BC) and quarter somatic cell count (QSCC) cure were chosen as secondary outcomes although low probabilities of BC and QSCC cure for selected cows were expected. The study resulted in the following findings: the pathogens mostly cultured from pretreatment samples were Streptococcus uberis, followed by Staphylococcus aureus and coagulase-negative staphylococci. There were no significant differences between the two test treatments in comparison with the reference treatment regarding all outcome variables. The sole therapy with Masti Veyxym® resulted in a numerically lower likelihood of BC without significant differences to the reference treatment. The combined therapy group showed a numerically higher nonrecurrence rate than the two other treatment groups and noninferiority compared to the reference treatment was proven. Having regard to the selection criteria of cows in this study, the findings indicated that sole treatment with Masti Veyxym® in nonsevere CM cases may constitute an alternative therapy to reduce antibiotics. However, noninferiority evaluations were mostly inconclusive. Further investigations with a larger sample size are required to confirm the results and to make a clear statement on noninferiority.
Mastitis is one of the most important diseases threatening modern dairy herds. The idea of fighting the disease through colonising the udder with lactic acid bacteria (LAB), thereby building a beneficial biofilm, is the base for a probiotic approach towards mastitis control. The purpose of this study was to screen 13 LAB strains (eleven wild strains, two ATCC strains) inhibitory to the growth of mastitis-causing pathogens for their in vitro ability to form a biofilm and to adhere to bovine glandular mammary epithelium in order to assess their probiotic potential. Furthermore, we aimed to gain knowledge about the chemical nature of the adhesins involved by subjecting the bacteria to various chemical and enzymatical pre-treatments. The biofilms were grown on hydrophilic glass and on hydrophobic polypropylene in de Man, Rogosa and Sharpe (MRS) broth and afterwards quantified with a crystal violet assay. Biofilm formation was observed in all strains. However, the extent strongly depended on the strain, surface charge and medium. The adhesion assay also revealed a strong strain dependency, but this trait was also present in all of the investigated LAB isolates. Depending on the strain, chemical or enzymatical pre-treatment revealed carbohydrate molecules as well as proteins and lipids to be crucial for the adhesion of LAB to epithelial cells. The seven strains showing the strongest biofilm formation and/or adhesion represent promising candidates for further investigation in order to develop a probiotic remedy for the treatment of mastitis. Still, their safety for consumers and patients as well as their capability to colonise the udder remain to be investigated in in vivo studies.