Dilma Scala Gelli

Food borne disease outbreaks caused by Salmonella Enteritidis

OBJECTIVE It is to describe outbreaks of salmonellosis reported from July 1993 through June 1997 in the Northwest region of S. Paulo State, Brazil, one of the areas where several foodborne outbreaks of salmonellosis have been recently detected. METHOD Data of 19 epidemiological investigations were analysed; 87 stool specimens and 38 food samples (including 12 of shell eggs) were processed for microbiological analysis. Salmonella strains were identified by serotyping, phagetyping and antimicrobial susceptibility testing. RESULTS There were 906 ill persons including 295 hospitalized patients. Phage type 4 (PT 4) Salmonella Enteritidis strains were isolated from 80.5% of stool samples, from all food samples and from 41.7% of eggs. Of the outbreaks, 95.7% were associated with the consumption of food containing raw or undercooked eggs. All strains were susceptible to the 13 antimicrobials, except the strains from the nosocomial outbreak. CONCLUSIONS The results obtained show the need for the implementation of control measures regarding egg and storage, as well as for guidance to the public as to the risks involved in the consumption of inadequately prepared eggs.

Inactivation by ionizing radiation of Salmonella Enteritidis, Salmonella Infantis, and Vibrio parahaemolyticus in oysters (Crassostrea brasiliana)

Irradiation is considered one of the most efficient technological processes for the reduction of microorganisms in food. It can be used to improve the safety of food products, and to extend their shelf lives. Oysters are considered one of the most important vehicles for pathogenic bacteria because of their feeding characteristics. The aim of this study was to evaluate the influence of a gamma radiation process on high levels of Salmonella Enteritidis, Salmonella Infantis, and Vibrio parahaemolyticus incorporated by oysters (Crassostrea brasiliana), as well as the effects of the process on the survival of the oysters and on their sensory attributes. The oysters were exposed to gamma radiation (60Co) in doses ranging from 0.5 to 3.0 kGy. A dose of 3.0 kGy was generally sufficient to reduce the level of Salmonella serotypes by 5 to 6 log10 units. A dose of 1.0 kGy was sufficient to produce a 6-log10 reduction in the level of V. parahaemolyticus. The highest irradiation dose did not kill the oysters or affect their sensory attributes. Hence, a dose of 3.0 kGy can be considered effective in inactivating Salmonella and V. parahaemolyticus in oysters without changing their odor, flavor, or appearance.

Pathogenic bacteria associated with oysters (Crassostrea brasiliana) and estuarine water along the south coast of Brazil

Abstract Oysters and estuarine water samples were collected monthly, from June 1998 to March 1999, in the Cananéia estuary, on the south coast of São Paulo, Brazil, and analyzed for bacterial hazards with and without depuration in filtered estuarine water. Aeromonas spp., Plesiomonas shigelloides, Vibrio cholerae O1, Vibrio parahaemolyticus, and Vibrio vulnificus were counted in oyster samples using the most probable number (MPN) and their presence verified in the surrounding estuarine water samples. The presence of Salmonella, Shigella, Escherichia coli O157:H7, and fecal coliforms counts were determined in oysters and in water samples too. Sixty percent of water samples contained fecal coliforms ranging from <1 to >200 CFU/100 ml and 100%, 30%, 20% and 10% were positive for V. parahaemolyticus, Salmonella, Aeromonas, and V. vulnificus in 5 l of water samples, respectively. In oyster samples, the fecal coliforms concentration ranged from <3.0 to ≥2.4 × 103 MPN/g in 40% of untreated and from <3.0 to 1.1 × 103 MPN/g in 40% of treated samples. Vibrio parahaemolyticus Kanagawa-negative was detected in all oyster samples and their concentration varied from 3.6 to ≥2.4 × 103 MPN/g. For the untreated oyster samples 80%, 70%, and 10% were positive for V. vulnificus (<3 – 11.0 MPN/g), Aeromonas (<3 – 15 MPN/g), and Salmonella (presence in 25 g), respectively. However, for treated oyster samples 60%, 30%, and 0% of them contained the same bacteria, respectively. Escherichia coli O157:H7, Shigella spp., P. shigelloides, and V. cholerae O1 were not detected in any of the samples. Fecal indicators did not correlate with Vibrio presence (p>0.05), although the isolation of Aeromonas species had a positive correlation (p = 0.017). The results showed no correlation between temperature, salinity, and bacteria (p > 0.05). The comparison between bacterial concentration in treated and untreated oyster samples, showed that only Aeromonas was higher in untreated oyster samples (p = 0.039). This study contributes toward creating a more global understanding of food-borne bacterial pathogens. The presence and concentration of viable bacterial hazards in oysters and water surrounding areas was determined for the first time on the south coast of São Paulo and it helps to define better the true microbial hazard in the aquatic environment and oysters.

Surto alimentar por Salmonella Enteritidis no Noroeste do Estado de São Paulo, Brasil

A foodborne outbreak which affected 211 persons occurred, in a School, in 1993. The epidemiological data obtained by interviewing the affected and non affected persons sampled showed as predominant symptoms: diarrhoea, fever (77.7%), abdominal cramps (67.7%), vomiting (65.8%), hot-and-cold sensations (54.5%) and headache (44.5%). The median incubation period was of 17 hours, the limits being 3 and 29 hours. The disease period was of from 3 to 4 days. The food concerned was a kind of pate, a mayonnaise mixture prepared with fresh eggs with boiled potatoes that was consumed with bread. The biological material analysis - 3 coprocultures, and leftovers of the food revealed the presence of one and the same organism: Salmonella Enteritidis. In the food, the numbers of this bacterium per gram were sufficient to account for the manifestation of the disease (104 and 105/g). The antibiogram of all the isolates showed the same sensibility pattern. The preparation related to this outbreak suggests the endogenous contamination of the eggs; the cross contamination - the outbreak affected three school periods, as the food was prepared separately for each school period; and the conditions under which the food was kept during the time from preparation to consumption. The observation of the 3 food handlers, by successive coprocultures, for one week, indicates that they were not asymptomatic carriers nor were they affected as a result of this outbreak by the causal bacteria.Em 1993 ocorreu um surto alimentar em escola, com 211 afetados. Os dados epidemiologicos levantados por entrevista de amostragem de afetados e nao afetados mostraram que os sintomas predominantes foram diarreia, febre (77,7%), dor abdominal (67,7%), vomito (65,8%), calafrios (54,5%) e cefaleia (44,5%). A mediana de incubacao foi de 17 horas, com limites entre 3 e 29 horas. A duracao da doenca foi de 3 a 4 dias. O alimento consumido foi um tipo de pate, mistura de molho de maionese preparada com ovos crus com batata cozida, passado em pao. A analise de material biologico (3 coproculturas) e de restos de alimentos revelou a presenca do mesmo microrganismo, a Salmonella Enteritidis. No caso dos alimentos, o numero encontrado desta bacteria por gramo de produto era compativel com a quantidade de celulas necessaria para desencadear a doenca (104e 105/g). O antibiograma de todas as cepas isoladas revelou o mesmo padrao de sensibilidade. As falhas no preparo do alimento relacionadas com o levantamento indicam a possibilidade de contaminacao endogena dos ovos; contaminacao cruzada - o surto afetou tres periodos escolares, sendo que para cada um o alimento foi preparado em separado - e as condicoes de manutencao do alimento apos preparo e ate o consumo. A observacao por uma semana seguida das 3 merendeiras envolvidas, atraves de coprocultura, nao indicaram que as mesmas fossem portadoras assintomaticas desta bacteria ou que tivessem sido envolvidas no surto em questao.A foodborne outbreak which affected 211 persons occurred, in a School, in 1993. The epidemiological data obtained by interviewing the affected and non affected persons sampled showed as predominant symptoms: diarrhoea, fever (77.7%), abdominal cramps (67.7%), vomiting (65.8%), hot-and-cold sensations (54.5%) and headache (44.5%). The median incubation period was of 17 hours, the limits being 3 and 29 hours. The disease period was of from 3 to 4 days. The food concerned was a kind of paté, a mayonnaise mixture prepared with fresh eggs with boiled potatoes that was consumed with bread. The biological material analysis-3 coprocultures, and leftovers of the food revealed the presence of one and the same organism: Salmonella Enteritidis. In the food, the numbers of this bacterium per gram were sufficient to account for the manifestation of the disease (10(4) and 10(5)g). The antibiogram of all th isolates showed the same sensibility pattern. The preparation related to this outbreak suggests the endogenous contamination of the eggs; the cross contamination-the outbreak affected three school periods, as the food was prepared separately for each school period; and the conditions under which the food was kept during the time from preparation to consumption. The observation of the 3 food handlers, by successive coprocultures, for one week, indicates that they were not asymptomatic carriers nor were they affected as a result of this outbreak by the causal bacteria.

Botulism: a laboratory investigation on biological and food samples from cases and outbreaks in Brazil (1982-2001)

Laboratory investigation of botulism from 1982 to 2001 confirmed the occurrence of eight positive outbreaks/cases of botulism in Brazil. From those, type A botulism was observed in seven of them. Biological material of one case (serum and feces) was positive in the first step of the bioassay, but the amount of sample was not sufficient for typification. One of the outbreaks that occurred in 2001 was negative for botulinum toxin in samples of serum, gastric washing and feces, collected eight days before the onset of the symptoms in the affected person who was clinically diagnosed as presenting the disease. Other two cases presenting compatible clinical diagnoses presented negative results. However, in those cases, the collection of samples was (1) after antiserum administration or (2) later than eight days of the onset of symptoms. Investigation was performed by mouse bioassay, as described in the Compendium of Methods for the Microbiological Examination of Foods (compiled by American Public Health Association--APHA)11, using specific antiserum from Centers for Disease Control (CDC), USA.

Detection of Salmonella in Foods Using Tecra Salmonella VIA and Tecra Salmonella UNIQUE Rapid Immunoassays and a Cultural Procedure

The presence of Salmonella in 200 raw food samples of animal origin was investigated by means of the rapid immunoassays Tecra Salmonella VIA and Tecra Salmonella UNIQUE (Tecra Diagnostics, Rosewille, New South Wales, Australia) and a cultural procedure. Forty-five samples (22.5%) were Salmonella positive by at least one of the three methods. The number of positive samples according to the analytical method was 34 (75.6%) for the cultural procedure, 29 (64.4%) for Tecra Salmonella VIA, and 27 (60.0%) for Tecra Salmonella UNIQUE. Tecra Salmonella UNIQUE detected three positive samples that were not detected by the two other methods. The cultural method also detected three positive samples that both rapid methods were unable to detect. McNemars chi-square tests indicated that the differences between results given by the rapid immunoassays when compared with those of the cultural method were not significant (P > 0.05).

Botulism in Brazil, 2000-2008: epidemiology, clinical findings and laboratorial diagnosis

Botulism is a rare and potentially lethal illness caused by Clostridium botulinum neurotoxin. We describe the findings of a laboratorial investigation of 117 suspected cases of botulism reported to the surveillance system in Brazil from January 2000 to October 2008. Data on the number and type of samples analyzed, type of toxins identified, reporting of the number of botulism cases and transmission sources are discussed. A total of 193 clinical samples and 81 food samples were analyzed for detection and identification of the botulism neurotoxin. Among the clinical samples, 22 (11.4%) presented the toxin (nine type A, five type AB and eight with an unidentified type); in food samples, eight (9.9%) were positive for the toxin (five type A, one type AB and two with an unidentified type). Of the 38 cases of suspected botulism in Brazil, 27 were confirmed by a mouse bioassay. Laboratorial botulism diagnosis is an important procedure to elucidate cases, especially food-borne botulism, to confirm clinical diagnosis and to identify toxins in food, helping sanitary control measures.

Botulism: considerations about eight cases occurred in Triângulo Mineiro, Minas Gerais, Brazil

Botulism constitutes a rare form of intoxication, particularly in our country. The only confirmed outbreak of this disease in Brazil occurred in the 50s in Rio Grande do Sul where nine persons acquired the disease after ingestion of home-canned fish. The present work reports an outbreak of type A botulism which occurred in eight members of the same family of whom seven contracted this food toxic infection after ingestion of home-canned pork. Two persons died and the others recovered after variable time of evolution. After eleven months a new case of botulism was diagnosed, but the source of this intoxication could not be found. The authors intend with this work to divulge the second confirmed outbreak of botulism in Brazil and to direct a special attention to ootulism clinical pictures, diagnostic and treatment pratically unknown in our country.

Estudo da radiosensibilidade ao 60CO do Vibrio cholerae O1 incorporado em ostras

OBJETIVO: Avaliar a eficiencia da radiacao ionizante por 60CO na eliminacao de Vibrio cholerae O1, El Tor Ogawa, nao-toxigenico, incorporados laboratorialmente em ostras vivas da especie Crassostrea brasiliana. METODO: Foram selecionadas amostras de ostras provenientes de Cananeia (litoral sul de Sao Paulo, Brasil), as quais foram contaminadas com Vibrio cholerae e irradiadas com doses de 0,5 kGy e 1,0 kGy. RESULTADOS: Foram observadas diminuicoes significativas do numero inicial do microrganismo indicado: de 3,4.10(7) para 10³ e 10², respectivamente. Os valores de D10 correspondentes foram de 0,173 a 0,235. CONCLUSAO: Adotando-se o fator 6 como nivel de seguranca, conclui-se que a dose de irradiacao de 1,41 kGy e necessaria para eliminar numeros elevados de celulas viaveis de V. cholerae em ostras. Os experimentos foram realizados com os controles respectivos.

Estudo da sensibilidade in vitro de diferentes cepas de Vibrio cholerae 01 à radiação gama de 60Co

A presenca de certos microrganismos nos alimentos ou de metabolitos originados durante sua multiplicacao pode dar lugar a varias enfermidades no homem: as intoxicacoes e as infeccoes alimentares. Dentre os agentes causadores das Enfermidades Transmitidas por Alimentos encontra-se o Vibrio cholerae 01. Estudou-se no presente trabalho a radiossensibilidade in vitro de quatro cepas de V. cholerae 01, submetidas ao tratamento com diferentes doses de radiacao ionizante de 60Co, e compararam-se os resultados obtidos com dados da literatura relacionados a problemas de veiculacao alimentar de bacterias patogenicas, incluindo a agua.