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H Hayashidani

Publications and source records attributed to H Hayashidani.

At least 19 recordsLinked to original sources
PubMed2005

Differences in heat resistance among pathogenic Yersinia enterocolitica depended on growth temperature and serotype.

To gain a better understanding about the effect of growth temperature on heat resistance of Yersinia enterocolitica, we determined decimal reduction times at 60 degrees C (D60-values) for O:3; O:5,27; O:8; and O:9 strains harboring virulence plasmid coding for Yersinia outer membrane protein and experimentally virulence plasmid-deleted strains after they were grown to stationary phase at 7, 25, or 37 degrees C. Bacteria were inoculated into Trypticase soy broth and were incubated at several temperatures. D60-values of O:3; O:5,27; and O:8 strains were larger when they were grown at 37 degrees C than at 7 or 25 degrees C, despite the presence or absence of virulence plasmids. However, similar D60-values were observed in O:9 strains, despite growth at 7, 25, or 37 degrees C. The results indicate two types of Y. enterocolitica strains, growth temperature-dependent and -independent, and a Yersinia outer membrane protein that is not directly involved in growth temperature-dependent heat resistance.

Bacterial Outer Membrane Proteins↗
PubMed2002

Isolation and characterization of Lactococcus piscium strains from vacuum-packaged refrigerated beef.

AIMS: To characterize gram-positive, catalase-negative, psychrotrophic, lactic acid-homofermentative, non-motile cocci isolated from vacuum-packaged refrigerated beef using phenotypic and genotypic methods. METHODS AND RESULTS: A total of 89 strains was isolated at 2 and 6 weeks as one of the predominant microflora of five samples of vacuum-packaged beef stored at 2 degrees C. The strains were compared with reference strains of some gram-positive, catalase-negative cocci using SDS-PAGE whole-cell protein pattern analysis, biochemical characterization and 16S rDNA sequencing. The biochemical and physiological characteristics of the isolates resembled those of Lactococcus piscium GTC 552(T). Numerical analysis of the SDS-PAGE whole-cell protein patterns resulted in close clustering of the strains with L. piscium GTC 552(T) (r > 0.68). Other Lactococcus and Leuconostoc species could be distinguished from the isolates using SDS-PAGE whole-cell protein patterns (r < 0.58) and biochemical characteristics. The 16S rDNA sequencing of four randomly selected strains showed that the strains differed from L. piscium GTC 552(T) by two to three bases in the highly variable region of the sequence. This is the first report on the isolation of L. piscium from vacuum-packaged beef. CONCLUSIONS: The gram-positive catalase-negative cocci isolated from vacuum-packaged refrigerated beef have been identified as L. piscium. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings of this work contribute to the knowledge of the microflora of vacuum-packaged refrigerated beef.

Animals↗
PubMed2001

Pulsed-field gel electrophoresis in differentiation of erysipelothrix species strains.

We report here the first analysis of Erysipelothrix spp. using pulsed-field gel electrophoresis (PFGE). Seventy strains of Erysipelothrix spp. were analyzed. SmaI, AscI, and NotI were tested for the ability to cleave the DNA extracted from those strains, and among them, SmaI was the most reliable enzyme. Sixty-three distinct PFGE patterns were produced, and no DNA degradation was observed, allowing the identification of all of the strains. Based on these results and on those of a previous analysis using randomly amplified polymorphic DNA and ribotyping, PFGE with SmaI might be considered to be more sensitive than those methods and to be the best method for epidemiological studies of strains of this genus.

Animals↗
PubMed2000

Lactobacillus algidus sp. nov., a psychrophilic lactic acid bacterium isolated from vacuum-packaged refrigerated beef.

Lactobacillus algidus sp. nov. is described on the basis of 40 strains isolated as one of the predominant bacteria from five specimens of vacuum-packaged beef collected from different meat shops and stored at 2 degrees C for 3 weeks. These strains were quite uniform in the overall characteristics examined. They are facultatively anaerobic, psychrophilic, Gram-positive, non-spore-forming, non-motile, lactic acid-homofermentative rods. The cells occurred singly and in pairs on agar media and in rather long chains in broth media. They differed in several cultural and biochemical characteristics from the authentic meso-diaminopimelic acid-positive or psychrophilic lactic acid bacteria in the genera Lactobacillus, Carnobacterium and Brochothrix. The SDS-PAGE whole-cell protein pattern was clearly distinctive. DNA-DNA hybridization and phylogenetic analysis of 16S rDNA also failed to associate these strains closely with any of the validly described organisms used. The phylogenetic analysis showed that these strains are rather remotely but most closely related to Lactobacillus mali (93% sequence similarity), which belongs to the Lactobacillus casei/Pediococcus group. Therefore, these strains should be included in the genus Lactobacillus and considered to represent a new species, Lactobacillus algidus sp. nov. The type strain is M6A9T (= JCM 10491T).

Animals↗
PubMed2000

Randomly amplified polymorphic DNA analysis of Erysipelothrix spp.

The usefulness of randomly amplified polymorphic DNA method (RAPD) to identify each species of genus Erysipelothrix and for epidemiological analysis of this genus was studied. Eighty-one strains and 18 random primers were tested. Among the tested primers, the primers NK51 (GGTGGTGGTATC) and NK6 (CCCGCGCCCC) produced noticeable results. The primer NK51 revealed four species-specific RAPD patterns. Of the 66 strains of E. rhusiopathiae, 64 had the same unique band of 884 bp. Of the 12 strains of E. tonsillarum, 11 produced a 1,265-bp band. In addition, two strains, previously thought to be E. rhusiopathiae, produced the 1,265-bp band, suggesting that they had been misclassified. One strain of E. tonsillarum produced the 884-bp band, suggesting that it too was E. rhusiopathiae. The E. rhusiopathiae strain of serovar 13 produced a 650-bp band, and the strain of serovar 18 produced a clear 420-bp band as well as three weak bands of 1,265, 918, and 444 bp. The primer NK6 revealed 14 RAPD patterns that were not serovar specific. However, different patterns were produced among strains of the same serovar showing that the RAPD method is able to identify the genetic variations of strains of this genus and can rapidly and easily differentiate strains of the same serovar. Based on these results, we concluded that the RAPD method with primers NK51 and NK6 is a rapid and reliable method to identify the species of this genus; we also concluded that this method might be a useful tool for the epidemiological analysis of the Erysipelothrix species.

Erysipelothrix↗
PubMed1999

Morphology of intestinal colonization of Yersinia enterocolitica serovar O3 in mice.

The present study was made to know the morphology of the initial invasion and lesions involved in the intestinal colonization of Yersinia enterocolitica serovar O3 in the epithelium of Peyer's patches of mice. Microfold (M) cells formed a specific structure like a pseudopodium and the bacteria were observed on the surface of the pseudopodium-like structure 4 hr after oral administration of serovar O3. The colonies of serovar O3 were observed in the epithelium and the lamina propria of the Peyer's patches dome region, and the bacteria grown in the Peyer's patches were in direct contact with the lumen without covered with the host tissue 24 hr after the administration.

Animals↗
PubMed1999

Prevalence and persistence of Salmonella in broiler chicken flocks.

Cecal contents of 2,345 broiler chickens consisting of 28 flocks originated from 12 farms were examined for the prevalence of Salmonella to know the actual status of infection with Salmonella in the chicken flocks. Salmonella was isolated from 336 (14.3%) samples. From these isolates, eight serovars were identified. Of the 336 Salmonella isolates, 242 (72.0%) were serotyped as S. Blockley, 60 (17.9%) S. Hadar, 15 (4.5%) S. Bredeney, nine (2.7%) S. Schwarzengrund, four (1.2%) S. Anatum, three (0.9%) S. Enteritidis, two (0.6%) S. Ohio, and one (0.3%) S. Livingstone. The same serovars of Salmonella were repeatedly found in the chickens from the same farms. S. Typhimurium and S. Enteritidis were detected in pooled broken eggshell samples collected from the hatchery. Analysis of plasmid profiles revealed 11 patterns of S. Blockley and seven patterns of S. Hadar. Strains of the same plasmid profiles of S. Blockley were isolated repeatedly from the same farm over one year after the first isolation.

Animals↗
PubMed1999

Bacterial contamination of ready-to-eat foods and fresh products in retail shops and food factories.

Raw vegetables cut for salad, cooked salad, cooked rice, boiled noodles, bean curd, and cooked Japanese foods were purchased in 27 retail shops in Tokyo. Intact vegetables before being processed and ready-to-eat fresh salad products were obtained from two food factories located in the suburbs of Tokyo. Two hundred thirty-eight retail samples, 137 samples of intact vegetables, and 159 samples of fresh products were examined for aerobic plate count (APC), coliforms, Escherichia coli, Listeria spp., Staphylococcus aureus, and Bacillus cereus. The APC of retail foods were 2.1 to 5.7 log CFU/g, and the range for the coliforms was 0.1 to 2.3 log CFU/g. The APC and coliform values showed that the raw vegetables cut for salad were the most heavily contaminated among the six kinds of ready-to-eat foods examined. Although L. monocytogenes was not detected, two samples of raw vegetables and five kinds of cooked foods yielded Listeria spp. S. aureus was detected in one sample of Japanese cooked food. The APC of the intact vegetables were 2.9 to 7.3 log CFU/g upon arrival and 2.2 to 7.2 log CFU/g after 3 days storage at 10 degrees C. The APC of the fresh products were 3.4 to 7.6 log CFU/g upon arrival and 4.7 to 8.7 log CFU/g after 3 days storage at 10 degrees C. The isolation rates for coliforms were 6.1 to 50% for intact vegetables and 50 to 66.7% for fresh products. E. coli was detected only in the fresh products. B. cereus was isolated from 20.1% (17 of 81) of the intact vegetables and 9.2% (8 of 87) of the fresh products.

Bacteria↗
PubMed1999

Bacterial contamination in the environment of food factories processing ready-to-eat fresh vegetables.

A total of 196 samples were collected from equipment for trimming, washing, slicing, soaking, dehydrating, blending, and packaging and from the floor and air of operation rooms before and after operation in two food factories processing ready-to-eat fresh vegetables located in the suburbs of Tokyo. Heavy contamination determined by an aerobic plate count of >5.0 log CFU/cm2 or ml was observed after operation in most of the samples examined, as were samples taken before operation on the interior surfaces of equipment for washing, slicing, dehydrating, and blending, the surfaces of blades for slicing, and the floor surfaces of operation rooms. From these environmental samples, the coliform group was detected before operation. Although 67 strains of 70 coliforms isolated were nonfecal, three Escherichia coli strains were detected in the surface of the operation room floors and the gloves of employees. Bacillus cereus was isolated from 9 of 86 and 17 of 85 samples examined before and after operation with the number of 2.0 to 3.0 log CFU/cm2 or ml. Listeria spp. were not detected in the environment of the food factories.

Bacillus cereus↗
PubMed1998

Occurrence of Erysipelothrix spp. in broiler chickens at an abattoir.

From September 1995 to August 1996, 750 chickens from 66 farms sent to an abattoir in Nagano Prefecture, Japan, were examined for the presence of Erysipelothrix spp. Erysipelothrix spp. were isolated from 118 (15.7%) of 750 skin samples, 27 (7.3%) of 372 hypoderm samples, 12 (1.9%) of 630 throat samples, 106 (59.2%) of 179 feather samples, and none of 257 spleen samples. Of 66 farms, 55 farms (83.3%) sent Erysipelothrix-positive chickens and 11 farms (16.7%) only negative ones. Of 297 Erysipelothrix isolates, 273 isolates were identified as Erysipelothrix rhusiopathiae and 24 as Erysipelothrix tonsillarum. E. rhusiopathiae isolates were serotyped into nine different serovars. Of the 273 E. rhusiopathiae isolates, 33 (11.1%) were serotyped to serovar 6; 22 (7.4%) were serovar 5; 19 (6.4%) were serovar 2; 15 (5.1%) were serovar 8; 2 (0.7%) were serovar 21; 4 each (1.3% each) were serovars 1b, 9, 12, and 19; and 178 (59.9%) were untypeable. Of 24 E. tonsillarum isolates, 15 (5.1%) were serotyped to serovar 3, and 9 (3.0%) were serovar 7. These findings indicate that chickens seem to be a potential reservoir of Erysipelothrix spp. in nature and to be a source of human Erysipelothrix infection.

Animals↗
PubMed1998

Occurrence of Erysipelothrix spp. in chicken meat parts from a processing plant.

From March 1996 to March 1997, 153 domestic raw chicken meat samples, including 71 thigh, 50 outer breast muscle, and 32 white meat samples, from a processing plant located in a chicken abattoir in Nagano Prefecture, Japan, were examined for the presence of Erysipelothrix spp. Erysipelothrix spp. were isolated from 49 (30.0%) of the 153 chicken meat samples. Of 67 Erysipelothrix isolates, 65 and 2 isolates were identified as E rhusiopathiae and E. tonsillarum. E. rhusiopathiae and E. tonsillarum isolates were serotyped into 11 and 2 different serovars, respectively. These findings might indicate that domestic chicken meat is frequently contaminated with E. rhusiopathiae and seems to be a potential source of human Erysipelothrix infection.

Abattoirs↗
PubMed1995

Experimental infection with Yersinia enterocolitica serovar 0:8 in beagle dogs.

Dogs were challenged orally with Yersinia enterocolitica serovar 0:8 biovar 1 for assessment of the infectivity of 0:8 bacteria. The bacteria were shed in the feces for 7-21 days following oral challenge. They were also recovered from intestinal contents and small intestinal Peyer's patches, but not from deeper organs of dogs euthanized 3 and 7 days after oral challenge. Dogs challenged subsequently with 10(10) bacteria showed protection from establishment of the bacteria in the intestinal tract. High titers of serum O-agglutinins developed in the dogs challenged with the bacteria. No clinical or hematological abnormalities were observed. The possibility that dogs may be a source of infection of 0:8 bacteria to human is discussed.

Agglutinins↗
PubMed1995

Development of intestinal lactobacilli in normal piglets.

The development of intestinal Lactobacillus spp. in 18 normal piglets from six litters was investigated from 1 to 45 d after birth. Faecal Lactobacillus strains isolated from piglets and their dams were identified at species and biovar levels on the basis of carbohydrate fermentation. A definite pattern was observed in the changes of four species and 20 biovars of lactobacilli appearing in faeces, with growth of the piglets. Lactobacillus reuteri colonized the animals on the first day of birth. The Lact. acidophilus group appeared 1 week after birth and maintained high levels in the intestine. Biovars B, C and E of Lact. reuteri were recovered as major biovars on the first to fourteenth days after birth. In the third and fourth weeks after birth, however, biovars F and G of Lact. reuteri were mainly recovered from piglet faeces. By the seventh week, biovars B, C and E predominated again in the intestine. No change in the composition of species and biovars of the genus Lactobacillus in the dams was detected.

Animals↗
PubMed1995

Potential sources of sporadic human infection with Yersinia enterocolitica serovar O:8 in Aomori Prefecture, Japan.

In November 1992 and June and August 1993 rectal contents from 204 small mammals living in the wild were collected and examined for the presence of Yersinia enterocolitica serovar O:8 to clarify the source of human infections caused by this microbe in the Tsugaru Region of Aomori Prefecture, Japan. Serovar O:8 was isolated from 10 (5.2%) of 193 wild rodents trapped in June 1993 (9 of 107) and August 1993 (1 of 23) but not from animals trapped in November 1992 (0 of 63). This serovar was not isolated from 11 moles. From May to September 1993, 12 human patients were found to have become ill and to be infected with Y. enterocolitica O:8. The patients lived in the same districts where the wild rodents harboring serovar O:8 were trapped. Two different patterns by restriction enzyme analysis of the virulence plasmid were observed. One pattern obtained by restriction enzyme analysis of the virulence plasmid was observed in 20 isolates from 11 human patients and 9 wild rodents, and the other was observed in 2 isolates from 1 human patient and 1 wild rodent. These findings indicate that wild rodents seem to play an important role as a source of human Y. enterocolitica O:8 infection.

Animals↗
PubMed1994

Infectivity and pathogenicity of Yersinia enterocolitica serovar 0:8 to wild rodents in Japan.

Three species of wild rodents, Anderson's red-backed voles (Eothenomys andersoni), large Japanese field mice (Apodemus speciosus) and small Japanese field mice (Apodemus argenteus), mainly living in mountainous areas in Japan, were challenged orally with Yersinia enterocolitica serovar 0:8 to determine infectivity and pathogenicity of this micro-organism with respect to wild rodents. Y. enterocolitica 0:8 was shown to colonize the intestinal tract of these three types of wild rodents, and was occasionally fatal. The faecal excretion period of these mice was 10-14 days in E. andersoni and A. speciosus, and 35-49 days in A. argenteus. Wild rodents recovering from the infection showed resistance to a second challenge with the same infectious agent. These results suggest that these three species of wild rodents living in mountainous areas in Japan may play an important role in the ecology of Y. enterocolitica 0:8.

Animals↗
PubMed1992

Isolation of Yersinia enterocolitica serovar O8 from free-living small rodents in Japan.

Yersinia species were isolated from 65 of 223 free-living small mammals trapped in 10 regions on Honshu Island in Japan. Of the 65 strains isolated, 1 was Yersinia enterocolitica serovar O3, 8 were Y. enterocolitica O5, 6 were Y. enterocolitica O8, 3 were Y. enterocolitica O9, and 1 was Yersinia pseudotuberculosis 4b. Of the six Y. enterocolitica O8 strains, five were positive for autoagglutination, Ca2+ dependence, and the 45-MDa virulence plasmid and showed high pathogenicity for mice.

Animals↗