The purposes of this study were to identify sources of Staphylococcus aureus on dairies and to determine whether S. aureus colonization of heifer body sites increases the risk of S. aureus IMI at parturition. In herds with high (> 10%) or low (< 3%) prevalence of S. aureus IMI, S. aureus was isolated from heifer teat skin, heifer external orifices, housing, feedstuffs, humans, nonbovine animals, air, and equipment. Additionally, in herds with high prevalence, S. aureus was isolated from bedding, insects, and water. The predominant sources of S. aureus for both groups were other IMI and heifer body sites. Heifers with prepartum lacteal secretions with S. aureus were at greater risk of S. aureus IMI at parturition than were prepartum heifers with lacteal secretions that were negative for S. aureus. Heifers with teat skin colonized by S. aureus were 3.34 times more likely to have S. aureus IMI at parturition than were noncolonized heifers. Overall, 35% of 700 heifers were colonized with S. aureus on a body site at least once. Although colonizations of most body sites appeared to be transient, a few heifers were colonized on the same site for 1 yr. Persistently colonized heifers may represent the primary reservoirs of S. aureus for other heifers.

Intramammary infection (IMI), also known as mastitis, is the most frequently occurring and economically the most important infectious disease in dairy cattle. This study provides a validation of the analytical specificity and sensitivity of a real-time PCR-based assay that identifies 11 major pathogen species or species groups responsible for IMI, and a gene coding for staphylococcal beta-lactamase production (penicillin resistance). Altogether, 643 culture isolates originating from clinical bovine mastitis, human, and companion animal samples were analyzed using the assay. The isolates represented 83 different species, groups, or families, and originated from 6 countries in Europe and North America. The analytical specificity and sensitivity of the assay was 100% in bacterial and beta-lactamase identification across all isolates originating from bovine mastitis (n = 454). When considering the entire culture collection (including also the isolates originating from human and companion animal samples), 4 Streptococcus pyogenes, 1 Streptococcus salivarius, and 1 Streptococcus sanguis strain of human origin were identified as Streptococcus uberis, and 3 Shigella spp. strains were identified as Escherichia coli, decreasing specificity to 99% in Strep. uberis and to 99.5% in E. coli. These false-positive results were confirmed by sequencing of the 16S rRNA gene. Specificity and sensitivity remained at 100% for all other bacterial targets across the entire culture collection. In conclusion, the real-time PCR assay shows excellent analytical accuracy and holds much promise for use in routine bovine IMI testing programs. This study provides the basis for evaluating the assay's diagnostic performance against the conventional bacterial culture method in clinical field trials using mastitis milk samples.

Study objectives were to determine the efficacy of 4 methods (intramammary amoxicillin, frequent milk-out, a combined intramammary amoxicillin and frequent milk-out, and no treatment) of managing mild to moderate clinical mastitis in a university dairy herd. Clinical and microbiological cures, milk production, disease progression, and California Mastitis Tests scores were evaluated. Cows meeting the study criteria were assigned to one of four treatment options based on a systematic randomization scheme (blocked by stage of lactation). Treatments were initiated prior to knowledge of culture results. Cows were observed and evaluated on d 1 to 8, 15, 22, 29, and 36. Overall, treatments were not significantly different than controls. However, when efficacy was evaluated by pathogen group, differences were observed. Intramammary amoxicillin appeared to be the most efficacious treatment for environmental streptococci. Frequent milk-out appeared to be detrimental for environmental streptococci. Treatment method appeared to have little effect on Escherichia coli mastitis, as nearly all cases recovered within a short time frame. None of the treatments were satisfactory for cases of Klebsiella mastitis. When obtained in a timely manner, treatment selection for clinical mastitis should be based on culture results.

Patients rated interpretation services highly no matter how they were provided but experienced only the method employed at the time of the encounter. Providers and interpreters were exposed to all three methods, were more critical of remote methods, and preferred videoconferencing to the telephone as a remote method. The significantly shorter phone interviews raise questions about the prospects of miscommunication in telephonic interpretation, given the absence of a visual channel, but other factors might have affected time results. Since the patient population studied was Hispanic and predominantly female care must be taken in generalizing these results to other populations.