Yasuji Katsube

Prevalence of Arcobacter species in retail meats and antimicrobial susceptibility of the isolates in Japan

A survey was conducted to examine the prevalence of Arcobacter species among meat samples and to investigate the antimicrobial susceptibility of the isolates in Japan. In 1998 and 1999, samples of beef (n=90), pork (n=100) and chicken meat (n=100) were purchased from seven retail shops. Arcobacter species were isolated from 2.2%, 7.0% and 23.0% of beef, pork and chicken meat samples, respectively. The rate of isolations in chicken meats was shown to be significantly higher than those of beef and pork. Species-specific polymerase chain reaction (PCR) demonstrated that the most dominant Arcobacter species was Arcobacter butzleri among the isolates examined. Multiple contaminations with different Arcobacter species were observed in 5% of the chicken samples. Almost all the strains tested showed resistance to vancomycin (100%) and methicillin (97.5%). Strains resistant to cephalothin, sulfamethoxazole-trimethoprim, nalidixic acid and chloramphenicol were detected at the rate of 81.1%, 67.2%, 53.5% and 24.6%, respectively. All Arcobacter strains examined were susceptible to ampicillin, tetracycline, streptomycin and kanamycin.

Seroprevalence of Bartonella henselae, Toxoplasma gondii, FIV and FeLV infections in domestic cats in Japan.

Seroprevalence of Bartonella henselae, Toxoplasma gondii, feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was investigated in 1,447 domestic cats derived from the north (Hokkaido) to the south (Okinawa) prefectures in Japan. Of the cats investigated, 8.8% (128/1,447) were seropositive to B. henselae, 5.4% (78/1,447) to T. gondii, 9.8% (107/1,088) to FIV, and 2.9% (32/1,088) to FeLV, respectively. For B. henselae infection, the positive rate varied from 11.5% in cats of 1 to <2 years old to 7.2% in those over 3 years old. Outdoor cats showed higher positive rate (14.5%) than that (7.0%) in indoor ones. The rate (13.5%) in flea‐infested cats was significantly higher than that (7.4%) in flea‐negative cats. The positive rates in southern and urban sites were more likely to be higher than those in northern and suburban sites, suggesting that warm and humid environments, density of cat population, and raising status, including hygienic condition and flea infestation in cats may correlate to higher seroprevalence of B. henselae infection. For T. gondii, FIV and FeLV infections, the seroprevalence also tended to be higher in outdoor, flea‐infested cats and advanced age groups. For FIV infection, the positive rates in male (14.3%) and outdoor cats (15.0%) were significantly higher than those in female (5.0%) and indoor cats (4.6%). On the other hand, no significant difference in seropositivities was observed in FeLV and T. gondii infections concerning to both genders and raising status.

Distribution of Arcobacter species among livestock in Japan

A survey was conducted to examine the distribution of Arcobacter species among livestock in Japan. During May 1999 and May 2000, fecal samples from cattle (n=332) and swine (n=250), chicken cloacal swabs (n=234), and vaginal swabs of cattle (n=61) and swine (n=15) were submitted for the isolation of Arcobacter species. Arcobacter species were isolated from 3.6 and 10.0% of the cattle and swine fecal samples, respectively, along with 14.5% of chicken cloacal swabs. No significant seasonal differences were observed. Species-specific polymerase chain reaction assay showed that A. butzleri was the most prevalent species (83.3, 60.0 and 47.1% of the cattle, swine and chicken isolates, respectively), followed by A. cryaerophilus 1B (16.7, 36.0 and 55.9% of the cattle, swine and chicken isolates, respectively). Of the samples from vaginal swabs, 8.1 and 13.3% were positive for Arcobacter in cattle and swine, respectively. This is the first report demonstrating the distribution of Arcobacter species among livestock in Japan.

Production of bacteriocin-like-substance by Listeria innocua against Listeria monocytogenes.

Cultures and culture filtrates of 129 Listeria innocua strains were examined for inhibitory activity against 18 strains of Listeria monocytogenes. Of the strains examined, 114 (88.4%) cultures and 126 (97.7%) culture filtrates had an inhibitory activity against strains of L. monocytogenes and most filtrates were sensitive to trypsin treatment. The authors concluded that most L. innocua strains produce a trypsin sensitive bacteriocin-like substance against L. monocytogenes.

Genomic diversity of Bartonella henselae isolates from domestic cats from Japan, the USA and France by pulsed-field gel electrophoresis

The genomic DNA diversity of 27 Bartonella henselae and three B. clarridgeiae isolates from 18 domestic cats from Japan, the USA and France was investigated by pulsed-field gel electrophoresis (PFGE) with NotI, AscI and SmaI restriction enzymes. A great diversity of genomic patterns was found for all B. henselae, but none for B. clarridgeiae isolates. The DNA size of B. henselae and B. clarridgeiae isolates were 1.7-2.9 and 1.7Mbp, respectively. All 13 Japanese cat isolates were identified as B. henselae type I. Furthermore, three of the four Japanese cats harbored genetically different B. henselae type I isolates, suggesting for the first time co-infection with various type I isolates. One French cat and one American cat were co-infected with B. henselae and B. clarridgeiae. B. henselae type I and type II were mainly grouped in two different clusters by PFGE using SmaI endonuclease in the dendrogram.

Serological Investigation of Bartonella henselae Infections in Clinically Cat‐Scratch Disease‐Suspected Patients, Patients with Cardiovascular Diseases, and Healthy Veterinary Students in Japan

Seroprevalence of Bartonella henselae was investigated in Japan in 48 individuals clinically suspected of having cat‐scratch disease (CSD), 159 patients with cardiovascular diseases, and 129 healthy veterinary students. Of 48 CSD‐suspected patients examined, 19 (39.6%) were positive for B. henselae‐IgG and 4 (8.3%) for B. henselae‐IgM. Of 159 patients with cardiovascular diseases, 5 (3.1%) were positive for B. henselae‐IgG. In healthy veterinary students, 14 of 129 (10.9%) were positive for B. henselae‐IgG and 1 (0.8%) for B. henselae‐IgM. The positive rates of B. henselae‐IgG and ‐IgM in CSD‐suspected patients were significantly higher than in other sources. Most CSD‐suspected and healthy individuals who were positive for B. henselae antibody had had some contacts with cats. In CSD‐suspected patients, the B. henselae positive rate in females was significantly higher than in males, and high seropositive rates to B. henselae were found in younger age groups.

Experimental feline toxoplasmosis.

The route of inoculation as well as stage of inoculated organism in its life cycle influenced the pathogenicity or infectivity of Toxoplasma in cats. All 6 cats administered orally with Toxoplasma cysts were infected without any clinical symptoms and excreted oocysts in the feces at the early stage of infection (5-12 days after administration). Of 3 cats administered orally with Toxoplasma oocysts, only one animal developed latent infection excreting oocysts in the feces at the end of 5th week after administration (38th, 40th day). On postmortem examination, none of infected animals showed abnormalities. Toxoplasma was recovered from the lung, striated musculatures and others. When cats were inoculated intraperitoneally with cysts, all of them developed fatal infection. Clinical signs were manifested by fever, anorexia, lethargy and dyspnea, which were similar to those of cats infected naturally. On postmortem examination, a large amount of fluid was found to have accumulated in the pleural and peritoneal cavities. Cloudy swelling of the liver and inflammatory edem of the lung were also observed. The level of SGOT and SGPT values was elevated significantly. None of animals inoculated intraperitoneally with cysts excreted oocysts in their feces though Toxoplasma was recovered from all tissues and organs of them. Intramusculally inoculation of cortisone acetate did not affect on relapsing or oocyst reproduction.

The Molar Combining Ratio of Anti‐Albumin Fab' Fragments to Homologous and Heterologous Serum Albumins

The number of antibody combining sites on bovine (BSA), goat (GSA) and sheep (SSA) serum albumins was studied using rabbit and chicken antibodies. In homologous reactions, the profiles of quantitative precipitations with chicken antibody were similar to those with rabbit antibody reported previously (12), and the antigenic valence in the extreme antibody excess zone was found to be 6–7 for each albumin.