The socalled enteropathogenic Escherichia coli (EPEC) O serogroups include typical and atypical EPEC, enterohaemorrragic E. coli, enterotoxigenic E. coli, and enteroaggregative E. coli. The aim of this article is to review the composition of each O serogroup and the major serotypes, clones, and additional virulence characteristics of each of these diarrheageniccategories. Their adherence patterns and genetic relationships are also presented. The review is based on the study of 805 strains of serogroups O26, O55, O86, O111, O114, O119, O125, O126, O1127, O128, and O142 most of which isolated in São Paulo from children with diarrhea between 1970 and 1990. Since some O serogroups include more than one diarrheageniccategory O serogrouping only should be abandoned as a diagnostic method. However serotyping is a reliable method for those serotypes that correspond to clones.

OBJETIVO: Avaliar a situação de contaminação por ácaros em grãos comercializados a granel em nove mercados municipais da cidade de São Paulo, no período de novembro/1989 a novembro/1990. MÉTODOS: Foram analisadas microscopicamente após tamisação 25 amostras de arroz polido e 53 de feijão, semanalmente até completar 42 dias, mantidas à temperatura ambiente. Outras alíquotas das amostras foram mantidas em estufa a 25°C e 75% de umidade relativa do ar (URA), durante 28 dias. RESULTADOS: As amostras apresentaram-se negativas para ácaros no primeiro dia de análise, sendo detectados após incubação. As amostras mantidas em estufa apresentaram maior percentual de exames positivos para ácaros (incidência): 31,7% (1.845 ácaros). As amostras mantidas no ambiente apresentaram 6,9% (45 ácaros). As amostras de arroz polido apresentaram maior contaminação do que as amostras de feijão. O maior percentual de ácaros ocorreu em temperatura média mensal de laboratório de 21,5ºC a 22,5°C (37,8%) e a uma umidade de 73,5% a 74,5% (31,1%). CONCLUSÕES: A espécie predominante foi Tyrophagus putrescentiae. A população de ácaros apresentou maior proliferação na primavera, verão e início do outono, devido à influência da temperatura e da URA.Tais resultados confirmam a importância de aprimorar o armazenamento de grãos, visando a não proliferação de ácaros.

OBJECTIVE: To evaluate mite contamination rate in grains commercialized in nine municipal markets of the city of São Paulo, in the period from November 1989 to November 1990. METHODS: 23 samples of polished rice and 53 samples of beans were microscopically examined after sieving, once a week and during 42 days at air temperature. Other sample fractions were kept in an incubator at 25°C and 75% Relative Humidity (RH) during 28 days. RESULTS: Samples were negative for mites in the first day of analysis and were detected after incubation. Samples incubated revealed a higher percentage of positive examinations for mites (incidence): 31.7% (and 1,845 mites); while samples kept at air temperature showed only 6.9% (and 45 mites). Samples of polished rice were more contaminated in comparison to the ones of beans. There was a larger amount of mites when the mean monthly temperature of the laboratory was between 21.5°C to 22.5°C (37.8%) and humidity between 73.5% to 74.5% (31.1%). CONCLUSIONS: The predominant species was Tyrophagus putrescentiae and other identified species were Blomia tropicalis, Cheyletus spp., Blattisocius tarsalis, and others. Mite population had a higher proliferation rate during spring, summer and in the beginning of autumn, due to highest temperature and humidity. These results confirm the importance of improving grains storage, to avoid mites proliferation.

OBJETIVO: Avaliar a situação de contaminação por ácaros em grãos comercializados a granel em nove mercados municipais da cidade de São Paulo, no período de novembro/1989 a novembro/1990. MÉTODOS: Foram analisadas microscopicamente após tamisação 25 amostras de arroz polido e 53 de feijão, semanalmente até completar 42 dias, mantidas à temperatura ambiente. Outras alíquotas das amostras foram mantidas em estufa a 25°C e 75% de umidade relativa do ar (URA), durante 28 dias. RESULTADOS: As amostras apresentaram-se negativas para ácaros no primeiro dia de análise, sendo detectados após incubação. As amostras mantidas em estufa apresentaram maior percentual de exames positivos para ácaros (incidência): 31,7% (1.845 ácaros). As amostras mantidas no ambiente apresentaram 6,9% (45 ácaros). As amostras de arroz polido apresentaram maior contaminação do que as amostras de feijão. O maior percentual de ácaros ocorreu em temperatura média mensal de laboratório de 21,5ºC a 22,5°C (37,8%) e a uma umidade de 73,5% a 74,5% (31,1%). CONCLUSÕES: A espécie predominante foi Tyrophagus putrescentiae. A população de ácaros apresentou maior proliferação na primavera, verão e início do outono, devido à influência da temperatura e da URA.Tais resultados confirmam a importância de aprimorar o armazenamento de grãos, visando a não proliferação de ácaros.

OBJECTIVE: To evaluate mite contamination rate in grains commercialized in nine municipal markets of the city of São Paulo, in the period from November 1989 to November 1990. METHODS: 23 samples of polished rice and 53 samples of beans were microscopically examined after sieving, once a week and during 42 days at air temperature. Other sample fractions were kept in an incubator at 25°C and 75% Relative Humidity (RH) during 28 days. RESULTS: Samples were negative for mites in the first day of analysis and were detected after incubation. Samples incubated revealed a higher percentage of positive examinations for mites (incidence): 31.7% (and 1,845 mites); while samples kept at air temperature showed only 6.9% (and 45 mites). Samples of polished rice were more contaminated in comparison to the ones of beans. There was a larger amount of mites when the mean monthly temperature of the laboratory was between 21.5°C to 22.5°C (37.8%) and humidity between 73.5% to 74.5% (31.1%). CONCLUSIONS: The predominant species was Tyrophagus putrescentiae and other identified species were Blomia tropicalis, Cheyletus spp., Blattisocius tarsalis, and others. Mite population had a higher proliferation rate during spring, summer and in the beginning of autumn, due to highest temperature and humidity. These results confirm the importance of improving grains storage, to avoid mites proliferation.