Incidence of non-01 Vibrio cholerae and Aeromonas spp. in fresh water in Araraquara, Brazil

The occurrence of Aeromonas spp., Vibrio cholerae, and Plesiomonas shigelloides in fresh water from various sources in Araraquara, State of São Paulo, Brazil was determined. Samples from ten distinct irrigation systems used in vegetable cultivation, from five distinct streams, from two reservoirs, from one artificial lake, and from three distinct springs were analyzed. All isolates were serotyped and tested for hemolysin, cytotoxin, heat-stable (ST) and heat-labile (LT) enterotoxins production; presence of plasmid; autoagglutination and drug resistance. V. cholerae isolates were also tested for cholera enterotoxin (CT) production, and Aeromonas isolates for suicide phenomenon. No P. shigelloides was found. V. cholerae non 01 was found in five irrigation water samples and in three stream samples. Aeromonas sp. were isolated in two samples of irrigation water, in three streams, and in one reservoir. All the V. cholerae and Aeromonas isolates were positive for P-hemolysin production, and all Aeromonas isolates were positive for suicide phenomenon; cytotoxic activities were observed in two Aeromonas strains. Cholera enterotoxin was not found in eight V. cholerae non-01 isolates tested by the Y-1 mouse adrenal cell. All isolates were also negative for the other virulence markers. Ii cholelerae isolates were found to be sensitive to the majority of drugs tested, while Aeromonas strains presented multiple drug resistance..

Prevalence and virulence properties of Vibrio cholerae non-O1, Aeromonas spp. and Plesiomonas shigelloides isolated from Cambe Stream (State of Parana, Brazil)

The incidence of Vibrio cholerae, Aeromonas spp, and Plesiomonas shigelloides was determined in Rater samples from Cambe Stream. The samples were collected from seven different sites. The serogroups, virulence markers and drug resistance profiles were also evaluated. Twelve. Aer. hydrophila, 12 Aer. caviae, eight Aer. sobria, seven Ple. shigelloides and two V. cholerae non-O1 were isolated. They belonged to different serogroups and all produced haemolysis in different assays. Five of the Aeromonas strains and one of V, cholerae non-O1 were positive for enterotoxin activity. Haemagglutination and its inhibition, using erythrocytes of different origins, was variable for Aeromonas spp and V. cholerae, while none of the Plt. shigelloides haemagglutinated in association with any type of erythrocyte. All isolates exhibited multiple drug resistance. These results indicate that the occurrence of V. cholerae non-O1, Aeromonas spp, and Ple. shigelloides, in water used for vegetable irrigation, human recreation and animal consumption, among others, represents a potential risk for humans.

Microbiological quality of ice used to refrigerate foods

Ice used for human consumption or to refrigerate foods can be contaminated with pathogenic microorganisms and may become a vehicle for human infection. To evaluate the microbiological content of commercial ice and ice used to refrigerate fish and seafood, 60 ice samples collected at six different retail points in the city of Araraquara, SP, Brazil, were studied. The following parameters were determined: total plate counts (37° C and 4° C), most probable number (MPN) for total coliforms, fecal coliforms and Escherichia coli, presence of Salmonella spp., Shigella spp., Yersinia spp., E. coli, Vibrio cholerae and Aeromonas spp.. Results suggested poor hygienic conditions of ice production due to the presence of indicator micro-organisms. Fifty strains of E. coli of different serotypes, as well as one Y. enterocolitica biotype 1, serogroup 0:5, 27 and phage type Xz (Ye 1/05,27/Xz) and one Salmonella Enteritidis phage type 1 (PT1) were isolated. Aeromonas spp., Shigella spp. and V. cholerae were not detected. The presence of high numbers of coliforms, heterotrophic indicator micro-organisms and pathogenic strains suggested that commercial ice and ice used to refrigerate fish and seafood may rep resent a potential hazard to the consumer in our community. © 2002 Elsevier Science Ltd. All rights reserved.