Portación de Staphylococcus aureus enterotoxigénico tipo A, en frotis nasofaríngeos en manipuladores de alimentos / Carriage of Staphylococcus aureus among food service workers

Background Staphylococcus aureus produces 11 serotypes of endotoxins that may cause food poisoning. Aim To determine the prevalence of type A enterotoxigenic Staphylococcus aureus carriage among food service workers in Chillan, Chile. Material and Methods Pharyngeal swabs were obtained from 100 food service workers and were cultured in Agar plates. After identifying the presence of Staphylococcus aureus, DNA was extracted to identify type A toxin by conventional PCR. Results Thirty eight percent of samples were colonized with Staphylococcus aureus. Among these, 26% were toxin A producers. Conclusions Half of the sampled workers carried Staphylococcus aureus and a quarter of these produced type A enterotoxin.

Habituation of enterotoxigenic Staphylococcus aureus to Origanum vulgare L. essential oil does not induce direct-tolerance and cross-tolerance to salts and organic acids

Enterotoxigenic Staphylococcus aureus strains that were isolated from foods were investigated for their ability to develop direct-tolerance and cross-tolerance to sodium chloride (NaCl), potassium chloride (KCl), lactic acid (LA) and acetic acid (AA) after habituation in sublethal amounts (1/2 of the minimum inhibitory concentration - 1/2 MIC and 1/4 of the minimum inhibitory concentration - 1/4 MIC) of Origanum vulgare L. essential oil (OVEO). The habituation of S. aureus to 1/2 MIC and 1/4 MIC of OVEO did not induce direct-tolerance or cross-tolerance in the tested strains, as assessed by modulation of MIC values. Otherwise, exposing the strains to OVEO at sublethal concentrations maintained or increased the sensitivity of the cells to the tested stressing agents because the MIC values of OVEO, NaCl, KCl, LA and AA against the cells that were previously habituated to OVEO remained the same or decreased when compared with non-habituated cells. These data indicate that OVEO does not have an inductive effect on the acquisition of direct-tolerance or cross-tolerance in the tested enterotoxigenic strains of S. aureus to antimicrobial agents that are typically used in food preservation.

Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding / Prevalência de genes codificadores de enterotoxinas e resistência antimicrobiana em estafilococos coagulase-negativo e coagulase-positivo isolados de morcilhas no sul do Brasil

INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS) and coagulasepositive (CoPS) isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa) and enterotoxin (se) genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82) were CoNS and 24.4% (20/82) were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8%) and Staphylococcus carnosus (15.9%) were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82) of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6%) and seb (27.5%). CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans.

INTRODUÇÃO: Estafilococos são patógenos responsáveis por surtos de doenças transmitidas por alimentos. O estudo investigou a prevalência de genes de enterotoxinas e o perfil de resistência aos antimicrobianos em estafilococos coagulase-negativo (CoNS) e estafilococos coagulase-positivo (CoPS) isolados de morcilhas no sul do Brasil. MÉTODOS: Duzentas colônias típicas e atípicas do ágar Baird-Parker foram inoculadas em ágar sal-manitol. Oitenta e dois estafilococos manitol-positivos foram submetidos a testes bioquímicos e perfil de susceptibilidade antimicrobiana. A presença dos genes da coagulase (coa) e enterotoxinas (se) foi investigada por reação em cadeia da polimerase (PCR). RESULTADOS: Os isolados foram divididos em dois grupos: 75,6% (62/82) CoNS e 24,4% (20/82) CoPS. Através dos testes bioquímicos, 9 espécies foram determinadas, Staphylococcus saprophyticus (37,8%) e Staphylococcus carnosus (15,9%) foram as mais prevalentes. Testes de susceptibilidade demostraram fenótipos de resistência aos antibióticos administrados em humanos, como gentamicina, tetraciclina, cloranfenicol e eritromicina. O gene coa foi detectado em 19,5% (16/82) das cepas e quatro fragmentos de DNA polimórficos foram observados. Cinco CoNS contendo o gene coa foram submetidos ao sequenciamento do 16S rRNA e três mostraram similaridade com CoNS. Quarenta amostras foram positivas para pelo menos um gene se, os mais frequentes foram sea (28,6%) e seb (27,5%). CONCLUSÕES: A presença de resistência aos antimicrobianos e de genes se nos isolados de morcilha indicou que este alimento pode representar um risco potencial à saúde, já que a presença nos alimentos pode causar doenças de origem alimentar ou ser uma possível rota de transferência de estafilococos resistentes aos humanos.

Brotes por Salmonella spp., Staphylococcus aureus y Listeria monocytogenes asociados al consumo de pollo / Outbreaks of Salmonella spp., Staphylococcus aureus and Listeria monocytogenes associated with poultry consumption. Systematic review.

Introducción. Las enfermedades transmitidas por alimentos son un serio problema de salud pública y, el pollo, uno de los alimentos asociados con ellas. Objetivo. Determinar la distribución y frecuencia de brotes alimentarios asociados al consumo de pollo contaminado por Salmonella spp., Listeria monocytogenes y Staphylococus aureus, mediante una revisión sistemática de la literatura científica. Materiales y métodos. Se buscaron los estudios de brotes asociados a Salmonella spp., S. aureus y L. monocytogenes, en las bases de datos Medline, Pubmed, Science Direct,SciELO,Librería Cochrane (CCRT),Biblioteca Virtual en Salud (BVS), Highwire,HINARI y MedicLatina. Se obtuvieron los datos para el cálculo de odds ratios (OR) mediante la elaboración de tablas de contingencia en el programa RevMan5™. Resultados. Siete artículos cumplieron con los criterios de inclusión y no se encontraron reportes de L. monocytogenes. El OR global fue de 3,01 (IC95% 2,37-3,81), lo que se interpreta como una asociación significativa entre el consumo de pollo contaminado y la infección alimentaria. Se presentó heterogeneidad en los estudios incluidos (p=0,03), por lo que fue necesario un análisis por subgrupos de microorganismos; para el caso de Salmonella spp., el OR fue de 2,67 (IC95% 2,09-3,41). No se hizo análisis para S. aureus por reportarse un solo artículo. Conclusiones. Se encontró un OR de 2,61, lo que indica que hay una fuerte asociación entre el consumo de pollo y la adquisición de salmonelosis. El principal factor de riesgo para adquirir salmonelosis es el consumo de pollo de asadero en los restaurantes.

Introduction. Food borne diseases are a serious public health problem. Poultry are often associated with these outbreaks. Objective. A systematic review of the literature is provided concerning the distribution and frequency of food borne outbreaks associated with consumption of chicken contaminated with Salmonella spp., Listeria monocytogenes and Staphylococcus aureus. Materials and methods. The search for studies of outbreaks associated with Salmonella, S. aureus and L. monocytogenes was conducted in Medline, Pubmed, Science Direct, Scielo, Cochrane Library (CCRT), Virtual Health Library (VHL), Highwire, HINARI and MedicLatina. Data were obtained for the calculation of odds ratio (OR) by preparing contingency tables using the RevMan5 program. Results. Seven articles met the inclusion criteria; however, no reports of L. monocytogenes were obtained. The overall OR was 3.01 (95% CI: 2.37, 3.81); this was interpreted as a significant association between the consumption of contaminated chicken and food poisoning. In the included studies heterogeneity (p= 0.03) was presented, so it took a subgroup analysis of microorganisms, in the case of Salmonella OR was 2.67 (95% CI: 2.09 -3.41). No analysis was made for S. aureus reported a single article. Conclusions. The OR indicated a strong association between chicken consumption and acquisition of salmonellosis. The main risk factor for acquiring salmonellosis is the consumption of chicken from grill restaurants.

Brote de enfermedad alimentaria en la localidad de El Huecú, provincia de Neuquén / Foodborne disease outbreak in El Huecú community, province of Neuquén

En febrero de 2006 ocurrió un brote epidémico de gastroenteritis aguda de origen alimentario, en ocasión de un festejo popular en una pequeña localidad de la provincia de Neuquén, Argentina. Aproximadamente 800 personas participaron de un almuerzo en las instalaciones del Gimnasio Municipal, y unas tres horas después de finalizado, cerca de 150 asistentes consultaron al hospital local, afectados por síndrome gastroentérico agudo. Se realizó una investigación epidemiológica caso-control a través de un muestreo representativo no probabilístico. Los resultados epidemiológicos establecieron un brote de ETA a fuente común, con una relación caso-control de 1:1,8. Los principales síntomas fueron cólicos abdominales (88%), vómitos (73,5%) y diarrea (60%). La torta que se sirvió en ese evento fue identificada como el alimento causal (OR 9,79; IC 95%; 2,66-36,00; valor p = 0,0001), sujeto a condiciones higiénico-sanitarias insatisfactorias en los diferentes procesos de elaboración, conservación y manipulación. De una porción de la torta se aisló una cepa de Staphylococcus aureus subespecie aureus, coagulasa positiva, enterotoxigénica, con un recuento de 2,4x10(6) UFC/g, y también se aisló este microorganismo de tres muestras de manos y narinas de personas involucradas en la preparación y el servicio. Las cepas aisladas de un operador y de la torta portaron el gen sea y presentaron el mismo patrón de SmaI-PFGE. Se atribuyó el brote de ETA a la contaminación durante el proceso de preparación de la torta consumida durante ese almuerzo popular, lo que podría estar relacionado con deficiencias en aspectos higiénicos y con la falta de refrigeración y de mantenimiento de la cadena de frío.

In the summer of 2006, an epidemic outbreak of acute gastrointestinal illness related to food consumption occurred in a small town in the province of Neuquén, Argentina. During a popular feast, approximately 800 local residents attended lunch held in the facilities of the Municipal Gymnasium. About three hours later, nearly 150 attendees sought medical assistance at the local hospital due to acute gastroenteritis. A case-control epidemiological investigation was conducted using representative non-probability sampling. The epidemiological investigation showed a common-source foodborne disease outbreak with a case-control ratio of 1:1.8. The main symptoms were abdominal cramps (88%), vomiting (73.5%) and diarrhea (60%). The cake was identified as the source of infection (OR 9.79; IC 95%, 2.66-36.00; p = 0.0001), and unsatisfactory hygienic conditions in food production, conservation and handling steps were identified. Coagulase positive, enterotoxigenic Staphylococcus aureus, subspecies aureus was detected in a piece of cake, with a count of 2.4x10(6) CFU/g, and in samples from the hands and nostrils of three people involved in food preparation and service. The strains isolated from both the cake and one of the food handlers carried the sea gene, and presented the same SmaI-PFGE pattern. The foodborne disease outbreak was considered to be due to contamination in the preparation process of the cake consumed at the feast, which was related to inadequate hygienic conditions, lack of refrigeration and cold chain disruption.

Brote de Toxi-Infección alimentaria asociado al consumo de leche ultrapasteurizada / Associated bud of nourishing Toxi-Infection to the ultrapasteurised milk consumption

Hace referencia a un estudio de caso sobre un brote de toxi-infección alimentaria asociada al consumo de leche ultrapasteurizada que tiene el objetivo de caracterizaral agente etiológico, se estima que las personas efectadas fueron 900, de las cuales 292 requirieron atención médica. El estudio se realizó con muestras de materia fecal de 12 pacientes, secreción nasal de 5 operarios de la planta y 3 muestras de leche, el resultado del estudio dió a la leche como vehículo de la toxi-infección y a un operario de la linea de producción como origen de la contimación de más de 50.000 litros de leche

Vigilancia epidemiológica de enfermedades transmitidas por alimentos en la Provincia de Río Negro, Argentina, 1993-2001 / Surveillance of foodborne diseases in the province of Rio Negro, Argentina, 1993-2001

A total of 39 outbreaks of foodborne diseases affecting 958 people in the province of Rio Negro, Argentina between 1993 and 2001 are described and evaluated. The main causal agents were identified involving food, sites of occurrence, risk factors and notification system used. Salmonella spp (38%), Trichinella spiralis (15%), Escherichia coli (13%) and Staphylococcus aureus (15%) were the most frequent agents present in outbreaks. Salmonella spp produced the largest number of cases (52%). Food involved were cooked meat (36%), cheese (10%), sandwiches (10%), deserts (10%) and ice cream (8%). Indeed, ice creams were involved in the largest number of cases and of people affected. In relation to the source of food, 41% of outbreaks were caused by homemade meals, 23% by catering or ice cream parlor, 13% in family parties, 8% in county fairs and 8% in hotel restaurants. In 28% of the outbreaks the etiological agent was identified exclusively by epidemiological analysis, in 64% isolation of the agent was carried out, and in 8% of the cases, a final diagnosis could not be obtained. Validity of epidemiological studies in foodborne disease, the necessity of strengthening the notification system of outbreaks, and the importance of good practices in food handling are analyzed.

Se describen 39 brotes de enfermedades transmitidas por alimentos que afectaron a 958 personasen la provincia de Río Negro, Argentina, en el período 1993- 2001. Se identifican los agentes causales, los alimentos involucrados, los sitios de ocurrencia, los factores de riesgo involucrados y los mecanismosde notificación empleados. Salmonella spp (38%), Trichinella spiralis (15%), Escherichia coli (13%) y Staphylococcus aureus (15%) resultaron los agentes más frecuentes en los brotes. Salmonella spp. tambiénprodujo el mayor número de casos (52%). Los principales alimentos involucrados resultaron cárneos (36%),quesos (10%), fiambres y sándwiches (10%), postres (10%) y helados (8%). El mayor número de casos, por suparte, fue causado por la ingestión de helados (37%). Con relación al origen de los alimentos, 41% de los brotesfueron causados por comidas elaboradas en los domicilios, 23% en establecimientos comerciales, 13% enfiestas familiares, 8% en fiestas comunitarias y 8% en restaurantes de hoteles. En el 28% de los brotes fueidentificado el agente etiológico por análisis epidemiológico exclusivamente, en el 64% se logró el aislamientodel agente, mientras que en el 8% de los casos no se logró el diagnóstico definitivo. Se analiza el valor de laencuesta epidemiológica en los estudios de enfermedades transmitidas por alimentos, la necesidad de fortalecerel sistema de notificación médica de casos y brotes y la importancia de las buenas prácticas en la manipulaciónde alimentos.

Staphylococcus aureus and food poisoning

Food-borne diseases are of major concern worldwide. To date, around 250 different food-borne diseases have been described, and bacteria are the causative agents of two thirds of food-borne disease outbreaks. Among the predominant bacteria involved in these diseases, Staphylococcus aureus is a leading cause of gastroenteritis resulting from the consumption of contaminated food. Staphylococcal food poisoning is due to the absorption of staphylococcal enterotoxins preformed in the food. Here, we briefly review the latest data on staphylococcal enterotoxins and some papers exemplifying the interactions between S. aureus and the food matrix; environmental factors affecting staphylococcal enterotoxin production are discussed

Parâmetros causadores de injúria celular em estafilococos, com ênfase a microrganismos competidores / Parameters causing cell injury in staphylococci, with emphasis on effect of competitive microorganisms

Os ensaios microbiológicos, com bactérias potencialmente patogênicas utilizados no controle de qualidade de alimentos, säo baseados em métodos microbiológicos empregados em espécimes clínicos. No entanto, as condiçöes ambientais dos patógenos nos dois tipos de materiais säo diferentes. Enquanto no material clínico, de modo geral, o microrganismo encontra um substrato ótimo, propiciando sua rápida multiplicaçäo até atingir um número elevado de células, no alimento, principalmente no industrializado, essas condiçöes ideais raramente ocorrem em virtude dos tratamentos físico e químico aos quais é submetido, como liofilizaçäo, altas temperaturas, acidificaçäo, reduçäo da atividade de água, bem como pela competiçäo com a microbiota existente. Essas condiçöes provocam danos às células bacterianas ou grande reduçäo de seu número, näo permitindo que cresçam de maneira satisfatória nos meios de cultura, ocasionando falsos resultados negativos. Com a finalidade de direcionar os cuidados a serem tomados na contagem de estafilococos injuriados, a revisäo discute os parâmetros causadores de injúria celular e enfatiza a influência dos microrganismos competidores sobre os estafilococos.

Intoxicaçäo por Staphylococcus aureus provocada por carne de peru defumada / Staphylococcus aureus infections caused by smoked meat of turkey

Carne de peru defumada preparada numa confeitaria do bairro de Laranjeiras, RJ, apresentado 4,0 x 10**7 Staphylococcus aureus enterotoxigênico/g, provocou intoxicaçäo em 4 pessoas de mesma família

Avaliaçäo analítica da produçäo de termonuclease pelo crescimento de Staphylococcus aureus em leite crú e pasteurizado / Analytic evaluation of thermonuclease production by Staphylococcus aureus in raw and pasteurized milk

O crescimento stafilocócico em dois níveis de inóculos, estirpe 100A, foi estudado comparativamente com a produçäo de termonuclease em leite pasteurizado e leite cru. O processo de extraçäo nestes produtos foi avaliado com o método analítico direto. O efeito dos inóculos iniciais de 10**3 e 10**6 UFC/ml no leite pasteurizado mostrou diferença estatisticamente significativa (P < ou = 0,05) no crescimento estafilocócico a 37-C durante 48 horas, com maior crescimento coincidindo com o inóculo mais elevado. Para o leite cru näo houve diferenca significativa entre os inóculos (P > ou = 0,05). Para ambos os produtos näo houve diferenças significativas para a produçäo de termonuclease ( P> ou = 0,05), durante o período de incubaçäo. Houve coerência dos achados entre a enumeraçäo de Staphylococcus aureus e produçäo de termonuclease, entretanto, quanto aos métodos de extraçäo e direto n adetecçäo desta enzima näo se alcançou perfeita concordância nos resultados

Determinaçäo comparativa de termonuclease em creme e manteiga contaminados experimentalmente con Staphylococcus aureus / Comparative determination of thermonuclease in cream and buter experimentally contamined by Staphylococcus aureus

A produçäo de termonuclease estafilocócica em creme e manteiga foi investigada para avaliar a contaminaçäo experimental de dois inóculos (10**3 e 10**6 UFC/ml) de Staphylococcus aureus patogênico. Também, os métodos direto e extrativo para quantificar a termonuclease foram comparados no creme e manteiga, observando-se nos produtos ricos em gordura maior tempo para a centrifugaçäo e difícil separaçäo da enzima precipitada quando se usava o processo extrativo, sugerindo-se por isto ensaios para viabilizar melhor esse método. No período de 48 h de incubaçäo dos inóculos 10**3 e 10**6 UFC/ml no creme näo houve diferença significativa no crescimento do S. aureus, porém para a manteiga registrou-se uma diferença com maior crescimento quando o inóculo foi 10**6 UFC/ml. Apesar de haver maior produçäo de termonuclease no inóculo mais elevado (10**6 UFC/ml), näo foi possível detectar diferenças significativas entre inóculos no creme e manteiga (P > ou = 0,05) para produçäo de termonuclease, talvez devido ao teor lipídico alto nesses produtos lácteos