Abstract Background Natural products represent important sources of antimicrobial compounds. Propolis and compounds from essential oils comprise good examples of such substances because of their inhibitory effects on bacterial spores, including bee pathogens. Methods Ethanol extracts of propolis (EEP) from Apis mellifera were prepared using different methods: double ultrasonication, double maceration and maceration associated with ultrasonication. Together with the antimicrobial peptides nisin and melittin, and compounds present in the essential oils of clove (Syzygium aromaticum) and cinnamon (Cinnamomum zeylanicum), assays were carried out on one Bacillus subtilis isolate and Paenibacillus alvei (ATCC 6344) against vegetative and sporulated forms, using the resazurin microtiter assay. Synergism with all the antimicrobials in association with tetracycline was verified by the time-kill curve method. Potassium and phosphate efflux, release of proteins and nucleic acids were investigated. Results EEPs showed the same MIC, 156.25 µg/mL against B. subtilis and 78.12 µg/mL against P. alvei. The peptides showed better activities against B. subtilis (MIC of 12 µg/mL for melittin and 37.50 µg/mL for nisin). Antimicrobials showed similar inhibitory effects, but cinnamaldehyde (39.06 µg/mL) showed the best action against P. alvei. Melittin and nisin showed the greatest capacity to reduce spores, regarding B. subtilis there was a 100% reduction at 6.25 and 0.78 µg/mL, respectively. Concerning P. alvei, the reduction was 93 and 98% at concentrations of 80 µg/mL of melittin and 15 µg/mL of nisin. EEPs showed the highest effects on the protein release against B. subtilis and P. alvei. Nucleic acid release, phosphate and potassium efflux assays indicated bacterial cell membrane damage. Synergism between antimicrobials and tetracycline was demonstrated against both bacteria. Conclusion All antimicrobials tested showed antibacterial activities against vegetative and sporulated forms of P. alvei and B. subtilis, especially nisin and melittin. Synergism with tetracycline and damage on bacterial cell membrane also occurred.

Abstract Listeria monocytogenes is a food pathogen responsible for many foodborne disease outbreaks. Listeria innocua is similar to L. monocytogenes, could be considered biologically similar to L. monocytogenes and could be used to predict its behavior. The aims of this work were to isolate Listeria spp. in dairy processing plants, perform genotypic characterization of virulence, evaluate the antimicrobial resistance profile, and verify the sensitivity of the strains to essential oils. Sampling was held in six dairy processing plants in the region of Campinas, Brazil. Seventeen Listeria innocua strains were isolated, all negative for virulence genes inlA, inlB, inlC, inlJ, actA, plcA, and plcB. The strains were resistant to kanamycin (5.9%), penicillin (11.8%), ampicillin (11.8%), cefoxitin (58.8%), clindamycin (76.50%) and oxacillin (100%). The susceptibility of the strains to commercial essential oils (Rosemarinus officinalis, Cymbopogon citratus, Eucalyptus citirodora, Mentha piperita, Piper nigrum, Vetiveria zizanioides, Cymbopogon nardus, Cymbopogon martinii and Pogostemon cablin) was evaluated by Minimum Inhibitory Concentration (MIC) test. The results showed Cymbopogon citratus, Cymbopogon martini, Cymbopogon nardus and Mentha piperita oils were most efficient. The resistance of Listeria innocua isolated in dairy processing plants is worrisome, and the use of essential oils could be an alternative for development of new drugs and products.

RESUMO: O queijo Minas frescal é muito apreciado no Brasil. Por ser fresco e úmido, seu tempo de prateleira é curto. A utilização de leite cru como matéria prima, a não maturação do queijo e a facilidade de contaminação durante seu processamento são fatores que comprometem a qualidade microbiológica do produto. Este trabalho verificou a qualidade higiênico-sanitária de 50 queijos Minas frescal comercializados na cidade de Botucatu, São Paulo, Brasil, em datas próximas a sua fabricação e na data de expiração da validade, utilizando os parâmetros propostos pela RDC nº 12 da Agência Nacional de Vigilância Sanitária (ANVISA). Cepas de S. aureus foram submetidas à pesquisa de genes codificadores de produção de enterotoxinas clássicas e, também, sua produção in vitro. Encontraram-se coliformes a 45ºC, acima do permitido por legislação, em 36% das amostras durante a primeira análise e, na segunda, em 44%. Quanto à contagem de estafilococos coagulase positiva, 10% não atendiam ao padrão exigido por lei na data de produção, e 14%, na data de expiração da validade. Salmonella foi apenas observada em uma amostra próxima à data de produção, enquanto L. monocytogenes somente em uma amostra na data de expiração da validade. Observou-se produção de Staphylococcal Enterotoxin B (SEB)e Staphylococcal Enterotoxin C (SEC) in vitro por três cepas de S. aureus. Ressalta-se, em decorrência disso, a importância de armazenar corretamente esse alimento, por seu potencial de causar intoxicação. Concluiu-se que a qualidade higiênico-sanitária desses queijos Minas frescais foi insatisfatória, implicando riscos para a saúde do consumidor.

ABSTRACT: The Minas fresh cheese is a fresh and moist cheese and, therefore, has a short shelf-life. The use of raw milk as the main feedstock, the absence of ripening and the facility of contamination are factors that can compromise the product’s microbiological quality. The aim of this study was to describe the hygienic-sanitary quality of 50 Minas fresh cheeses marketed in Botucatu city, São Paulo, Brazil, close to their production date, and another 50 units from the same lot exactly on the expiration date, according to the Brazilian Sanitary Surveillance Agency (ANVISA). We also searched for enterotoxins genes in Staphylococcus aureus and its in vitro expression. In 36% of the first analyzed samples, the count of coliforms at 45ºC was above the limit and, as for the second analysis, 44%. Regarding coagulase positive staphylococci, 10 (20%) samples showed concentration above the permitted by law next to the production date and 14% on the expiration date. Salmonella was only observed in one sample analyzed near the date of production, while L. monocytogenes only in one sample analyzed on the expiration day. We isolated three enterotoxigenic strains of S. aureus that produced Staphylococcal Enterotoxin B (SEB) and Staphylococcal Enterotoxin C (SEC) in vitro, highlighting the importance of proper storage of this product due to its potential to cause intoxication. Overall, the quality of Minas fresh cheese is still unsatisfactory, leading to risks to consumers’ health.

O sistema Diramic foi avaliado para o diagnóstico das infecções do trato urinário (ITU). O sistema Diramic foi desenvolvido em Cuba e possibilita resultados de diagnóstico das infecções do trato urinário (ITU) em quatro horas e baseia-se na variação da turvação do crescimento microbiano no meio de cultura após incubação a 37ºC/4 horas. 396 amostras de urinas provenientes de ambulatórios e enfermarias do HC da FMB-UNESP-Botucatu/SP foram analisadas pelo sistema Diramic. O método da alça calibrada (AC) foi adotado como método de referência. A taxa de coincidência entre os dois métodos foi de 96,46% (382 amostras de urina), não havendo diferença significativa entre os resultados obtidos nos dois métodos. Os resultados para sensibilidade e especificidade foram 84,37 e 98,80% respectivamente e 10 resultados no Diramic foram falsos negativos (2,5%) e 4 falso positivos (1,01%). Os microrganismos identificados nas urinas positivas foram Escherichia coli (68,75%), Klebsiella pneumoniae (10,94%), leveduras (6,25%), Pseudomonas aeruginosa (4,69%), Enterobacter cloacae (3,12%) e Proteus mirabilis, Staphyloccocus coagulase negativo, Morganella morganii e Citrobacter freundii também foram identificadas (1,56% para cada espécie). O método Diramic foi eficiente na triagem das urinoculturas, porém verificou-se algumas restrições quanto ao diagnóstico das infecções do trato urinário quando causadas por leveduras e em pacientes submetidos a antibioticoterapia.

The use of the Diramic system in microbiological diagnosis of urinary tract infections (UTI) was evaluated. This system was developed at the National Center for Scientific Research of Cuba, and it reads turbidimetric changes of microbial growth in culture media at 37ºC incubated for 4 hours. A total of 396 urine specimens were tested in the Laboratory of Microbiology of the School of Medicine - UNESP, Brazil using the Diramic system and the counting of colony forming units per urine millimeter (calibrated loop) as the reference method. The coincidence rate between the two methods was 96.46% (382 urine samples), and the differences in results were not significant (p<0.05). Sensitivity and specificity rates were 84.37% and 98.80%, respectively. False negative and false positive rates were 2.50% and 1.01%, respectively. The microorganisms isolated from positive urines were: Escherichia coli (68.75%); Klebsiella pneumoniae (10.94%); yeast (6.25%); Pseudomonas aeruginosa (4.69%); Enterobacter cloacae (3.12%); Proteus mirabilis, coagulase negative Staphylococcus, Morganella morganii, and Citrobacter freundii (1.56% each). The Diramic system was effective as screening method for urine cultures, however restrictions in the UTI diagnosis caused by yeasts and patients undergoing antibiotic therapy were negative characteristics of the system.