A total of 35 samples (1000 ml each) of pasteurized milk and 25 samples (100 g each) of white cheese purchased at supermarkets in Rio de Janeiro were analyzed for the presence of Aeromonas. Strains of Aeromonas were isolated from 28.5% of pasteurized milk and 32% of white cheese samples. Standard Plate counts in the pasteurized milk samples ranged from 7.2 × 10* to 2.5 × 105 CFU/ml. Total and fecal coliform counts in white cheese samples ranged from 1.9 × 10* to 2.4 × 105 most probable number per g and 3.2 × 102 to 1.2 × 105 most probable number per g, respectively. It was possible to identify Aeromonas caviae (58.9%), Aeromonas hydrophila (12.8%), and Aeromonas schubertii (2.5%) among the cultures isolated from pasteurized milk samples. Twenty-five percent of the strains could only be classified as Aeromonas spp. In white cheese samples, unclassified strains were the most frequent isolates (61.5%) followed by A. hydrophila (26.9%), A. caviae (7.6%) and Aeromonas sobria (3.8%). Only strains of A. hydrophila and A. sobria showed high rate of positive results when tested for the production of hemolysin, cytotoxin, and staphylolytic activity. Heat-stable enterotoxin and autoagglutination test did not correlate as virulence factors. The presence of Aeromonas species in refrigerated food samples suggests that this microorganism could be a potential foodborne pathogen, and dairy products may represent an important vehicle of its transmission.

Fresh and salt water samples analyzed in Rio de Janeiro city showed the presence of Plesiomonas shigelloides. Forty-six strains were isolated from both environments. A high incidence of P. shigelloides was achieved in polluted fresh and salt waters as well as in samples from non-polluted streams. P. shigelloides isolates had biochemical characteristics similar to those already described in the literature. None of the isolates analyzed produced enterotoxin in the suckling mouse assay. Hemolytic activity against sheep and human type A erythrocytes was detected in the strains tested. The results of the antibiotic susceptibility tests indicated that all the isolates were susceptible to the cephalosporins, penicillins combined with a beta-lactamase inhibitor, aminoglycosides, imipenem, norfloxacin, tetracycline, chloramphenicol and trimethoprim-sulfamethoxazole. All the isolates were resistant to the penicillins.

Anti-Brucella agglutinins were found in 5 of 53 (9.4%) vampire bats Desmodus rotundus, captured in the State of Bahia, Brasil. Two specimens of Diphylla ecaudata were negative. Fifty specimens of the small monkey, Callithrix penicillata, were also negative.

Thirty-seven (16.9%) of 219 raw milk samples and 38 (13.7%) of 280 pasteurized milk samples were positive for Yersinia sp. The isolates from raw milk samples include Yersinia enterocolitica (32.4%) comprising biotype 1 (0:5, 10.8%), and biotype 2 (0:10 K1, 1.6%); Yersinia intermedia (64.9%) comprising 0:18 (40.5%), 0:7,8 (8.1%), 0:16 (2,7%) and non-typable (13.5%) and Yersinia frederiksenii (0:22, 2.7%). The isolates from pasteurized milk samples include Y. enterocolitica (41.5%) comprising 0:5 (31.7%), 0:13 (2.4%), 0:7,8 (2.4%) and 0:16 (4.8%); Y. frederiksenii (56.1%) comprising 0:27 (7.3%), 0:25,35 (12.2%), non-typable (36.6%) and Y. intermedia (non-typable, 2.4%). Most Y. enterocolitica and about one third of non-Y. enterocolitica strains produce heat-stable toxin (ST). Antibiotic susceptibility, autoagglutination capacity and calcium-dependency of strains also were investigated.