Staphylococcus aureus was isolated from 44 (74.6%) of 59 rats (Rattus norvegicus) from a fish market in Chiba Prefecture and 9 (34.6%) of 26 rats from a slaughterhouse in Kanagawa Prefecture. Of 104 isolates from the fish market, the most frequent was 81 strains (77.9%) of biotype C, followed by 16 strains (15.4%) of biotype B, 6 strains (5.8%) of biotype A and untypable 1 strain (1.0%). Eight (88.9%) of 9 isolates from the slaughterhouse were of biotype G and 1 (11.1%) was of biotype B. The coagulase types of isolates from the fish market were of VIII (26.9%), I (22.1%), VII (13.5%), IV (8.7%), II (5.8%), III (2.9%), V (2.9%), VI (2.9%) and untypable (14.4%), while those from the slaughterhouse were of VIII (44.4%), V (22.2%), VII (22.2%) and untypable (11.1%). Twelve isolates from 9 rats in the fish market produced enterotoxins A (11 strains) and B (1 strain).
ABSTRACT Germ‐free chickens were monocontaminated or dicontaminated with microorganisms isolated from the cecal contents and feces of chickens. In the case of monocontamination, the viable number of organisms in the alimentary tract considerably varied depending on the species or genus. Staphylococcus epidennidis. Streptococcus faecalis var. liquefaciens and Escherichia coli became established in much larger numbers in germ‐free chickens than in ordinary birds. While Bifidobacterium thermophilum and Catenabacterium sp. were unable to become established, other anaerobic organisms and a strain of yeast became established almost at the same level as in the ordinary microflora. Anaerobic non‐sporeforming gram‐positive rods (AR), which were occasionally found in the ordinary chickens, were always well established throughout the gut of monocontaminated birds. In the case of dicontamination, the numbers of S. epidermidis, Catenabacterium sp. and B. thermophilum were comparable to those in the ordinary microflora. Growth of S. epidermidis was suppressed by E. coli. Catenabacterium sp. and B. thermophilum became well established when given in combination with other bacteria, except that the establishment of B. thermophilum in combination with Catenabacterium sp. was irregular. Growth of AR was prevented when administered together with E. coli . On the other hand, the numbers of E. coli and S. faecalis var. liquefaciens were continuously large even in the presence of any other bacterium.
A total of 18 strains of Fusobacterium necrophorum, of which 15 were freshly isolated from bovine liver abscesses, apparently normal bovine liver tissues, bovine rumen fluids and heifer mastitis secretions, were submitted to detailed characterization of overall cultural and biochemical properties, guanine-plus-cytosine (G+C) contents of deoxyribo-nucleic acids and pathogenicity for mice. The strains were divided into two groups on the basis of colonial and cellular morphologies, growth mode in liquid medium, hemagglutination titer and pathogenicity for mice. The two groups of organisms were considered to correspond to bivars A and B of Fievez in F. necrophorum. This differentiation of groups was substantiated by the results of deoxyribonucleic acid homology tests; the homology indices among the strains of the two groups were 53 to 76%. This level of deoxyribonucleic acid homology was in accordance with that of subspecies proposed by Johnson for the genetic definition of taxonomic groupings.
A total of 593 cats consisting of 144 adults and 449 kittens obtained from Animal Protection Center, Prefecture of Kanagawa, were examined. Of these, 51 (8.6%) had Campylobacter, 12 (2.1%) had Yersinia, and 8 (1.4%) had Salmonella. In adult cats, the respective recovery rates of the 3 bacteria were 9.0, 5.8, and 2.1% and in kittens, 8.5, 0.9, and 1.1%. Of 64 Campylobacter strains, 48 from 36 cats were identified as C. jejuni and 16 from 16 cats were as C. coli. Of 12 Yersinia strains, 6 were identified as Y. enterocolitica, 5 were as Y. frederiksenii, and 1 was as Y. pseudotuberculosis. Biovars (Wauters) of the 6 Y. enterocolitica strains were biovar 1 (5 strains) and biovar 2 (1 strain) and their serovars were 06 (1 strain), 07 (1 strain), 014 (1 strain), and ungroupable other than 01 to 033 (3 strains). Eight Salmonella strains were all identified as S. choleraesuis subsp. choleraesuis and belonged to 4 serovars, agona (3 strains), blockley (3 strains), braenderup (1 strain), and typhimurium (1 strain). These results indicate that Campylobacter is carried in the healthy pet cats more frequently than Yersinia and Salmonella.
Eighteen strains of Shiga toxin-producing Escherichia coli (STEC) were isolated from 14 (8.9%) of 158 fecal samples from slaughtered cattle. Isolate serotypes were 015 (1 strain), 028ac (1 strain), 0119 (2 strains), 0126 (1 strain), 0157 (2 strains), and OUT (11 strains). Isolates of 0157 (2 strains) and OUT (4 strains) harbored 3 virulence factors (the stx gene, the eaeA gene, and the hlyA gene); 28ac (1 strain) and OUT (2 strains) harbored 2 factors (the stx gene and the hlyA gene). PCR examinations were performed on 233 fecal samples for STEC virulence factors. Of them, 55 (23.6%) were positive for stx genes. Of these, 19 samples were positive for 3 factors (the stx gene, the eaeA gene, and the hlyA gene); 18 were positive for 2 factors (the stx gene and the hlyA gene); and 1 was positive for 2 factors (the stx gene and the eaeA gene). Factor detection rates varied from farm to farm.
A total of 40 strains of Listeria monocytogenes which have been demonstrated to be serovar 1/2a, 1/2b, and 4b were genotyped by pulsed-field gel electrophoresis (PFGE) after separate digestion with Apa I, Asc I, Sma I, and Sse 8387 I. Twenty-seven unrelated strains including four representative strains showed distinctly different genotypes according to their PFGE profiles. Then nine strains isolated from shredded cheese of different lots and four strains isolated from the cheese-processing environment were shown to display the same genotype. Therefore, it is suggested that the Listeria was spread in cheese by cross-contamination from the cheese-processing environment. Thus, PFGE analysis has a good typeability and excellent discriminatory power, and has provided a useful tool for investigation of the source of Listeria contamination.
