Staphylococcus aureus is one of the most common microorganisms responsible for high morbidity and mortality in humans and animals. Methicillin-resistant S. aureus are responsible for several outbreaks worldwide and therapeutic arsenal has become scarce. The present investigation verified the epidemiological profile of S. aureus strains isolated from the veterinary hospital staff, from dairy cattle workers and also from milk samples of dairy cattle presenting mastitis. Samples were characterized phenotypically by antibiogram, catalase, and coagulase tests, and also by Voges-Proskauer test. The isolated strains were characterized genotypically by specific Polymerase Chain Reaction and Amplified Ribosomal DNA Restriction Analysis (ARDRA). From the 218 isolated strains, 27 were identified as S. aureus (12%), four of them were resistant to oxacillin and two of them were classified as MRSA (Methicillin-resistant S. aureus). The prevalence of isolated strains among animal personnel care was low (2%) but all MRSA isolates were found among the clinical staff. Results of ARDRA pointed out that S. aureus strains isolated from different animal care personnel were grouped in the same cluster when HindIII and HinfII restriction enzymes were used. When ARDRA was performed with HaeIII enzyme, the formation of two clusters was observed, but the isolated strains were not correlated. The prevalence of S. aureus strains isolated was higher in clinical staff and the biochemical and molecular assays of them presented 100% of correlation.

Previous studies have reported on the phytotherapeutic potential of propolis from southern Brazil (Urupema, Santa Catarina State), in particular, its efficacy in the treatment of bovine mastitis. The present study evaluates the effect of seasonal variation on the chemical composition of propolis from southern Brazil and its resultant antimicrobial and cytotoxic activities in the context of treating bovine mastitis. Antimicrobial activity against Staphylococcus aureus was assessed, along with the cytotoxicity and induction of apoptosis in MAC-T bovine mammary epithelial cells. With the exception of spring propolis, the flavonoid quercetin was the main compound present in all samples. The minimum inhibitory concentration (MIC) of propolis against S. aureus from mastitic milk was 140 μg/mL for samples collected during the spring, autumn, and winter seasons, but 280 μg/mL for samples collected in summer. For MAC-T cells, the spring propolis extract was more toxic with an IC50 of 120 μg/mL. However, for 120 μg/mL of spring propolis extract, only 0.77% of necrotic and 37% of apoptotic MAC-T cells were found, respectively. Nonetheless, the induction of cell deaththrough apoptosis by propolis extract suggests less severe damage to bovine mammary glands. Moreover, only negligible seasonal variation was found in the chemical composition of propolis from southern Brazil, and no biological activities were determined to be harmful. Therefore, this propolis shows promise as an alternative to commercial antimicrobials in the control of bovine mastitis, offering support for organic milk production.

During a year (March/2004 to February/2005) 140 samples of raw milk, dairy staff, and Minas Frescal cheese were analyzed for the presence of S. aureus in a dairy plant in Goiás, Brazil. Strains were isolated from 75% of the personnel investigated resulting in 31 (33.7%) isolates from 92 collected samples (46 from hands and 46 from nasopharynx). The 24 raw milk samples resulted in 18 (75.0%) positive samples and 26 isolates, with mean number: 1.1 x 10(5) CFU/ml. Among 24 cheese samples 17 (70.8%) were positive resulting in 20 isolates, with mean number: 3.8 x 104 CFU/g. Thirteen samples (54.2%) were above the limit established by the brazilian legislation (10³ CFU/g). The differentiation of strains was performed by antimicrobial susceptibility test. All isolates were susceptible to ciprofloxacin and gentamicin. Resistance was observed in five (6.5%) isolates for erythromycin, 19 (24.7%) for tetracycline, one (1.3%) for vancomycin, four (5.2%) for oxacillin and 53 (68.8%) isolates for penicillin. Eleven isolates (14.3%) were susceptible to all antibiotics tested and 18 (23.4%) were resistant to more than one antibiotic. The antibiotic susceptibility allowed the discrimination of isolates in 12 different profiles (A-L), but the phenotypic typing failed to determine the source of bacteria for the cheese. | O trabalho teve por objetivo isolar, identificar e caracterizar fenotipicamente utilizando o antibiograma, Staphylococcus aureus isolados de manipuladores, leite cru e queijo Minas Frescal, em um laticínio de Goiás. Durante doze meses (Março/2004 a Fevereiro/2005) 140 amostras foram analisadas. As cepas foram isoladas de 75% dos manipuladores resultando em 31 (33,7%) isolados a partir de 92 amostras coletadas (46 de mãos e 46 de nasofaringe). Das 24 amostras de leite cru, 18 (75,0%) foram positivas, resultando em 26 isolados, com média de contagem de 1,1 x 10(5) UFC/ml. Das 24 amostras de queijo 17 (70,8%) foram positivas originando 20 isolados, com média de 3,8 x 10(4) UFC/g, sendo 13 (54,2%) com população acima do limite estabelecido pela legislação brasileira (10³ UFC/g). A tipagem das cepas foi feita pelo antibiograma, através do método de difusão em placas. Todos os isolados foram susceptíveis à ciprofloxacina e gentamicina. Foi observada resistência em cinco (6,5%) isolados para eritromicina, 19 (24,7%) para tetraciclina, um (1,3%) para vancomicina, quatro (5,2%) para oxacilina e 53 (68,8%) para penicilina. Onze (14,3%) isolados foram susceptíveis a todos os antibióticos testados e 18 (23,4%) foram resistentes a mais de um antibiótico. O antibiograma permitiu a classificação das cepas em doze perfis diferentes (A-L), porém não foi uma técnica eficiente em determinar a origem da contaminação final do queijo.

Staphylococcus aureus is one of the major agents of contagious mastitis and has high incidence worldwide in most of dairy herds. Besides the economic impact, the public health aspects of the enterotoxins and the toxic shock syndrome toxin are very important. The enterotoxin A is frequently correlated with food related illness in man and can be associated with raw, pasteurized and other milk products. The toxic shock syndrome is caused most frequently by toxic shock syndrome toxin, but enterotoxins B and C also can be implicated. The aim of this study was to verify the occurrence of Staphylococcus aureus enterotoxins and toxic shock syndrome toxin producers. Milk samples from cows with clinical and subclinical mastitis were collected. The results of toxins research by "celofane over agar" to TNAase and by commercial kit to enterotoxins were associated with the electronic somatic cell count. Total of 209 milk samples from cows with clinical and subclinical mastitis caused by S.aureus were verified. A total of 209 (98.86%) were TNAase producers, nine samples (4.39%) were enterotoxin producers, and one of them (0.49%) was EED producer, three (1.46%) EEC producers and three (1.46%) EEB producers. The toxic shock syndrome toxin was not identified in any of the samples assayed on this study. There was no statistical correlation between the somatic cell count results and the samples with toxin production. | O Staphylococcus aureus é um dos principais agentes das mastites consideradas contagiosas, apresentando elevada incidência na maioria dos rebanhos leiteiros em vários países. Além de perdas econômicas é importante salientar o aspecto de saúde pública para cepas produtoras de enterotoxinas e da toxina do choque tóxico. A enterotoxina A, relacionada com maior ênfase nos casos de toxinfecções alimentares, pode ser veiculada pelo leite cru, pasteurizado e subprodutos lácteos. A síndrome do choque tóxico é determinada mais freqüentemente pela toxina do choque tóxico, porém as enterotoxinas do tipo B e C também podem ser implicadas. O objetivo deste estudo foi verificar a ocorrência de S.aureus produtores de enteroxinas e da toxina do choque tóxico em amostras de leite de animais com mastite subclínica, e correlacionar estes resultados com a contagem de células somáticas; utilizando a técnica de "celofane over agar" para detecção da TNAase, kit comercial para identificação das enterotxinas e contagem eletrônica de células somáticas. Avaliod]MORENO, B.[u-se 209 amostras de leite oriundas de vacas com mastite subclínica por S.aureus, e dentre estas, 209 (98,86%) produziram TNAse, nove amostras (4,39%) foram produtoras de enterotoxinas, sendo que uma (0,49%) dentre elas foi produtora de EED, três (1,46%) de EEC, e três (1,46%) de EEB. Em uma amostra (0,49%), detectou-se concomitantemente EEA e EEB e em outra EEB e EEC. A toxina do choque tóxico não foi encontrada nas cepas avaliadas neste estudo, assim como não houve aumento estatisticamente significativo, na contagem de células somáticas, das amostras de cepas produtoras de enteroxinas.