Staphylococcus aureus Alpha-Toxin in Deep Tracheal Aspirates-Preliminary Evidence for Its Presence in the Lungs of Sepsis Patients.

The pore forming alpha-toxin (hemolysin A, Hla) of Staphylococcus aureus (S. aureus) is a major virulence factor with relevance for the pathogenicity of this bacterium, which is involved in many cases of pneumonia and sepsis in humans. Until now, the presence of Hla in the body fluids of potentially infected humans could only be shown indirectly, e.g., by the presence of antibodies against Hla in serum samples or by hemolysis testing on blood agar plates of bacterial culture supernatants of the clinical isolates. In addition, nothing was known about the concentrations of Hla actually reached in the body fluids of the infected hosts. Western blot analyses on 36 samples of deep tracheal aspirates (DTA) isolated from 22 hospitalized sepsis patients using primary antibodies against different epitopes of the Hla molecule resulted in the identification of six samples from five patients containing monomeric Hla (approx. 33 kDa). Two of these samples showed also signals at the molecular mass of heptameric Hla (232 kDa). Semiquantitative analyses of the samples revealed that the concentrations of monomeric Hla ranged from 16 to 3200 ng/mL. This is, to our knowledge, the first study directly showing the presence of S. aureus Hla in samples of airway surface liquid in human patients.

Decision-Making of Swiss Farmers and the Role of the Veterinarian in Reducing Antimicrobial Use on Dairy Farms.

The reduction of antimicrobials on dairy farms is a topical issue and confronts both veterinarians and farmers with major challenges. The aim of this study was to investigate dairy farmers' motivation to reduce antimicrobial use on their farms. Factors influencing dairy farmers' decision-making regarding dairy cow health were identified and the role of the veterinarian in these processes was characterized. A customized structured questionnaire was sent to all participants (n = 59) of an ongoing antimicrobial reduction project among dairy farmers in the Canton of Fribourg, Switzerland, by mail. Fifty-eight completed questionnaires were returned and evaluated (response rate 98.3%). The majority of respondents were men (56/58, 96.6%) and farm managers (55/57, 96.5%) managing their farms as their main occupation (56/57, 98.2%). Using a 5-point-Likert-scale (1 = not a reason, 5 = very important reason), respondents ranked "My veterinarian is putting pressure on us to use less antimicrobials" (median=2.5, interquartile range = 1-3) and "Other farmers also reduce antimicrobial use" (2.0, 1-3) as the least important factors affecting their motivation to reduce the use of antimicrobials in dairy cows (P < 0.001). Respondents ranked their veterinarian's opinion (4.0, 4-5) and their own feelings and knowledge (4.0, 3-4) as the two factors having significantly more importance on their decisions regarding dairy cow management (P < 0.001). The farmers indicated they were satisfied with the quality of the consultancy given by their veterinarians (4.0, 4-5) and with the quality of communication with veterinarians (4.0, 3-4). They indicated that they understood recommendations made by the veterinarian (4.0, 3.75-4) and also felt understood by the veterinarian (4.0, 3-4). However, only 25.9% (14/54) indicated they were willing to pay for good quality, farm-adapted consulting by their veterinarian. Based on these findings, veterinarians play an important role in influencing Swiss dairy farmers in decision-making concerning animal health and treatment. However, veterinarians were not viewed by farmers as important motivators for reducing antimicrobial use. Swiss veterinarians are encouraged to be aware of their influence on farmers' decisions and to use that influence to more clearly promote antimicrobial reduction on dairy farms.

Reducing Antimicrobial Use by Implementing Evidence-Based, Management-Related Prevention Strategies in Dairy Cows in Switzerland.

The aim of this study was to reduce antimicrobial use (AMU) on dairy farms that implemented evidence-based management strategies. The study not only examined whether these strategies led to a reduction in AMU in practice, but also examined the influence of the level of their implementation on AMU. For data analysis, practice software recordings of the farm veterinarians were used. The AMU data of 50 farms with prevention strategies applied (intervention group, IG) over 3 years (2017-2019) and of 74 farms without prevention strategies (control group, CG) over 2 years (2018-2019) were analyzed. Project participation was supported with 500 Swiss francs (~545 USD) per farmer per year. The AMU was compared between the IG and CG using the treatment incidence. In December 2017/January 2018, the farmers of the IG had chosen at least one of the proposed 17 prevention strategies from one of three sectors, i.e., udder health, uterine health and/or replacement calf health. The prevention strategies, were developed in a standard operating procedure protocol and were discussed in detail with the farmers before the implementation. Forty-eight farms chose at least one udder strategy, 10 farms at least one uterine strategy and 37 farms at least one calf strategy. By choosing an udder health strategy or a uterine health strategy, the corresponding systemically administered AMU could be significantly reduced (p < 0.04) in the IG compared with the CG. In addition, udder strategies that were well-implemented led to a significant reduction (p = 0.05) of intramammary "highest priority critically important antimicrobials (HPCIA)" (quinolones, cephalosporins 3rd and higher generation, macrolides and ketolides, glycopeptides, and polymyxins). The level of implementation was significantly lower in 2019 compared to 2018 (p < 0.05, Fisher's exact test). No significant reduction in AMU could be achieved for the calf sector. A reduction of AMU in dairy farms is possible by implementing evidence-based management-related prevention strategies. The level of implementation has only an influence on the consumption of HPCIA. The reduction of AMU in practice by means of evidence-based measures requires supportive human resources instead of financial support, because financial support for farmers seems not to motivate them sufficiently.

Veterinary peer study groups as a method of continuous education-A new approach to identify and address factors associated with antimicrobial prescribing.

Within the dairy industry, most antimicrobials are used for dry-cow therapy or mastitis treatment. To reduce antimicrobial usage in dairy cows, increasing awareness and behaviour change is necessary. As veterinarians are known to be influenced by their peers, peer study groups as a continuous education might contribute to this. Therefore, the objective of this study was to analyse written records of veterinary peer study group meetings to identify factors associated with antimicrobial prescribing decisions, and to analyse veterinarians' attitude towards the benefits of this continuous education method. Twenty-three participating Swiss cattle practitioners were divided into three groups. Each group met every two to five months, together with a facilitator and an expert on the topic to be discussed. Written records from every meeting were taken and analysed qualitatively to identify factors influencing veterinarians' decisions on antimicrobial prescribing and mastitis therapy. In addition, focus group discussions were conducted after the last meeting, to assess the veterinarians' learning achievements gained during the peer study group meetings. Extrinsic factors such as external pressure, competition, farmer, individual animal, farm and diagnostics as well as intrinsic factors such as own experience/attitude, knowledge and change of mindset during career could be shown to influence veterinarians' decisions on antimicrobial prescribing. In the focus group discussions, the veterinarians stated that they gained new knowledge, received new stimuli, exchanged with their peers and felt supported in their relationship to their farmers. Since the identified factors are partly interrelated, it is not sufficient to change a single factor to achieve a change in the antimicrobial prescription behaviour of veterinarians. Veterinary peer study groups could contribute to the intention to change, because veterinarians experienced multiple benefits from this method of continuous education. In order to quantify this, the prescription data of the veterinarians are analysed in a next step.