Salmonella serotypes, resistance patterns, and food vehicles of salmonellosis in southern Brazil between 2007 and 2012.

INTRODUCTION: Previous studies have identified Salmonella as the main causative agent of foodborne diseases in the state of Rio Grande do Sul (RS), southern Brazil, between 1997 and 2006. This study aimed to describe the Salmonella serotypes, antimicrobial patterns, and food vehicles of salmonellosis that occurred in RS between 2007 and 2012. METHODOLOGY: Information about Salmonella isolates and salmonellosis outbreaks registered in the official records of the Central Laboratory of RS (FEEPS/IPB-LACEN/RS) was analyzed. RESULTS: Among the 163 isolates investigated, 138 (84.7%) were identified as S. Enteritidis. The second and third most frequent serovars identified were S. Schwarzengrund (5.5%) and S. Typhimurium (3.7%). Homemade mayonnaise was the food vehicle most frequently identified (17.39%), followed by pastry products (15.94%) and beef (12.32%). Antimicrobial resistance was analyzed; 12 drugs were tested. Higher percentages of resistance were observed to nitrofurantoin (94.2%) and nalidixic acid (89.1%). The resistance to these two drugs was verified in 80.43% of the isolates. Multi-resistance to three and five drugs was verified in four and two isolates, respectively. CONCLUSIONS: Comparing the results of the present study with results of previous reports, it was possible to conclude that S. Enteritidis and homemade mayonnaise are still the main serotype and food vehicle of salmonellosis in RS and that antimicrobial resistance has been increasing among S. Enteritidis responsible for foodborne outbreaks in southern Brazil.

O desinfetante hipoclorito de sódio como barreira sanitária: condições de atividade frente a Staphylococcus aureus isolados em alimentos envolvidos em surtos de toxinfecções alimentares / The disinfectant sodium hypochlorite as a sanitary barrier: activity conditions against Staphylococcus aureus isolated from foods implicated in foodborne disease outbreaks

Para monitorar a eficácia do desinfetante hipoclorito de sódio como barreira sanitária, foi avaliada a atividade frente a 32 isolados de Staphylococcus aureus obtidos, no IPB-LACEN/RS, em alimentos envolvidos em surtos de toxinfecções alimentares. Foi usado o teste de suspensão com o seguinte delineamento: solução com 200 ppm de cloro livre na ausência e presença de matéria orgânica (1% de leite integral); solução com100 ppm de cloro livre; quatro tempos de contato (5, 10, 15 e 30 min). Como resultados: com 200 ppm, na ausência de matéria orgânica, todas os isolados foram inativados; com 200 ppm e matéria orgânica, 27 isolados permaneceram viáveis mesmo após 30 min de contato; a solução com 100 ppm necessitou de 30 min para que 24 isolados se apresentassem inativos. Concluiu-se que, para o uso deste desinfetante na proteção da saúde de comensais frente ao gênero bacteriano confrontado, o recomendado é uma solução com pelo menos 200 ppm de cloro livre, tempo de contato não inferior a 30 min e resíduos orgânicos nas superfícies com níveis inferiores a 1%.

Quantification and molecular characterization of Salmonella isolated from food samples involved in salmonellosis outbreaks in Rio Grande do Sul, Brazil / Quantificação e perfil molecular de Salmonella isolada de alimentos envolvidos em surtos de salmonelose no Rio Grande do Sul

Data concerning the prevalence and populations of Salmonella in foods implicated in outbreaks may be important to the development of quantitative microbial risk assessments of individual food products. In this sense, the objective of the present study was to assess the amount of Salmonella sp. in different foods implicated in foodborne outbreaks in Rio Grande do Sul occurred in 2005 and to characterize the isolated strains using phenotypic and genotypic methods. Nineteen food samples involved in ten foodborne outbreaks occurred in 2005, and positive on Salmonella isolation at the Central Laboratory of the Health Department of the State of Rio Grande do Sul, were included in this study. Food samples were submitted to estimation of Salmonella using the Most Probable Number (MPN) technique. Moreover, one confirmed Salmonella colony of each food sample was serotyped, characterized by its XbaI-macrorestriction profile, and submitted to antimicrobial resistance testing. Foods containing eggs, mayonnaise or chicken were contaminated with Salmonella in eight outbreaks. Higher counts (>10(7) MPN.g-1) of Salmonella were detected mostly in foods containing mayonnaise. The isolation of Salmonella from multiple food items in five outbreaks probably resulted from the cross-contamination, and the high Salmonella counts detected in almost all analyzed samples probably resulted from storing in inadequate temperature. All strains were identified as S. Enteritidis, and presented a unique macrorestriction profile, demonstrating the predominance of one clonal group in foods involved in the salmonellosis outbreaks. A low frequency of antimicrobial resistant S. Enteritidis strains was observed and nalidixic acid was the only resistance marker detected.

Dados sobre a prevalência e a população de Salmonella em alimentos implicados em surtos podem contribuir na condução de análises de risco. Dessa forma, o objetivo desse estudo foi determinar a quantidade de Salmonella sp. presente em alimentos implicados em surtos ocorridos no Rio Grande do Sul em 2005 e caracterizar os isolados por meio de técnicas fenotípicas e genotípicas. Dezenove amostras de alimentos obtidas em dez surtos ocorridos em 2005 e identificadas como positivas para Salmonella no Laboratório Central da Secretaria da Saúde do Estado do Rio Grande do Sul foram incluídas no estudo. A quantificação de Salmonella foi feita pela técnica do Número Mais Provável (NMP). Ao lado disto, uma colônia de Salmonella obtida de cada amostra de alimento foi submetida à sorotipificação, macro-restição com XbaI e determinação de resistência a antimicrobianos. Salmonella esteve presente em alimentos a base de ovos, maionese e frango em oito surtos. As contagens mais elevadas (>10(7) NMP.g-1) foram detectadas principalmente em alimentos contendo maionese. O isolamento de Salmonella de vários alimentos em cinco surtos resultou, provavelmente, da contaminação cruzada, enquanto as elevadas contagens encontradas, em quase todos os alimentos, podem ser explicadas por armazenamento em temperatura inadequada. Todos os isolados foram identificados como S. Enteritidis, e apenas um perfil foi encontrado na macro-restrição, demonstrando a predominância de um grupo clonal desse sorovar nos surtos de salmonelose. Uma baixa freqüência de isolados de S. Enteritidis resistentes a antimicrobianos foi encontrada, sendo a resistência ao ácido nalidíxico o único perfil encontrado.

Quantification and molecular characterization of Salmonella isolated from food samples involved in salmonellosis outbreaks in Rio Grande do Sul, Brazil.

Data concerning the prevalence and populations of Salmonella in foods implicated in outbreaks may be important to the development of quantitative microbial risk assessments of individual food products. In this sense, the objective of the present study was to assess the amount of Salmonella sp. in different foods implicated in foodborne outbreaks in Rio Grande do Sul occurred in 2005 and to characterize the isolated strains using phenotypic and genotypic methods. Nineteen food samples involved in ten foodborne outbreaks occurred in 2005, and positive on Salmonella isolation at the Central Laboratory of the Health Department of the State of Rio Grande do Sul, were included in this study. Food samples were submitted to estimation of Salmonella using the Most Probable Number (MPN) technique. Moreover, one confirmed Salmonella colony of each food sample was serotyped, characterized by its XbaI-macrorestriction profile, and submitted to antimicrobial resistance testing. Foods containing eggs, mayonnaise or chicken were contaminated with Salmonella in eight outbreaks. Higher counts (>10(7) MPN.g(-1)) of Salmonella were detected mostly in foods containing mayonnaise. The isolation of Salmonella from multiple food items in five outbreaks probably resulted from the cross-contamination, and the high Salmonella counts detected in almost all analyzed samples probably resulted from storing in inadequate temperature. All strains were identified as S. Enteritidis, and presented a unique macrorestriction profile, demonstrating the predominance of one clonal group in foods involved in the salmonellosis outbreaks. A low frequency of antimicrobial resistant S. Enteritidis strains was observed and nalidixic acid was the only resistance marker detected.