Norwalk-like virus genes were detected by RT-PCR in the caecum contents of pigs. Positive PCR products were produced from four out of 1,117 samples by nested PCR using human SRSV primers. Nucleotide sequences between 4,561 and 4,852 numbered according to the Norwalk virus genomic RNA in the RNA polymerase region were determined. Between the Norwalk virus sequence and the sequences detected in pigs, there was 58.2% to 59.9% sequence homology. The swine sequences were located on genogroup II of human SRSVs, but formed a subgroup in the phylogenetic tree of caliciviruses.

The prevalence of Coxiella burnetii antibodies was investigated by indirect immunofluorescence (IF) test in 55 paired sera (acute and convalescent phases) of school children who had influenza-like symptoms. Of the convalescent serum samples examined, 18 (32.7%) sera reacted positively to phase II antigen of C. burnetii. Coxiella-like organism was isolated from the sera of 13 children after injection of the 18 acute phase sera into mice. The organism was identified as C. burnetii by Giemsa staining and the IF antigen test of mouse spleen smears, the polymerase chain reaction (PCR) method, electron microscopic observations of the mouse spleen cells, and the IF antibody test of mouse sera. This is the first report of isolation of C. burnetii from serum specimens of children having influenza-like symptoms. The evidence that C. burnetii was isolated from people indigenous to Japan at a considerably high incidence suggested that C. burnetii may be widespread as a cause of influenza-like symptoms in Japan.

ABSTRACT. Coxiella burnetii was isolated by inoculation into cyclophosphamide-treated mice from 9 of 29 (31%) vaginal swabs collected from feline clients at veterinary clinics in Shizuoka city. -KEY WORDS: Coxiella burnetii, feline, vagina.

Escherichia albertii is an emerging foodborne pathogen. The source of infection in most foodborne outbreaks is unknown, as it is difficult to isolate E. albertii from suspected foods or water. E. albertii has a broad host range among birds and can be isolated from chicken meat. In this study, PCR assay, enrichment and isolation conditions for detecting E. albertii in chicken meat were evaluated. The growth of 48 E. albertii strains isolated in Japan between 1994 and 2018 was evaluated in modified EC broth (mEC) and mEC supplemented with novobiocin (NmEC) and on different media containing carbohydrates. In addition, the enzyme for nested PCR, the enrichment condition, the most probable number (MPN) method, and agar media were also evaluated for chicken meat. To distinguish E. albertii from presumptive non-E. albertii bacteria, desoxycholate hydrogen sulfide lactose agar (DHL), MacConkey agar (MAC), and these agars supplemented with rhamnose and xylose (RX-DHL and RX-MAC, respectively) were used. All E. albertii strains grew in mEC and NmEC at both 36°C and 42°C and did not utilize rhamnose, sucrose, or xylose. Both the first PCR and nested PCR, using TaKaRa Ex Taq which was 10–100 times superior to the other enzymes, showed positive results in enrichment culture of 25 g of chicken meat inoculated with >20 CFU of E. albertii in mEC and NmEC at 42°C for 22 ± 2 h. Thus, the first PCR was sensitive enough to detect E. albertii in chicken meat. The MPN values in mEC and NmEC were 0.5- and 2.3-fold of inoculated bacterial concentration, respectively. E. albertii in chicken meat was more efficiently isolated with enrichment in NmEC (70.1-100%) and plating onto RX-DHL (85.4%) and RX-MAC (100%) compared to enrichment in mEC (53.5-83.3%) and plating onto DHL (70.1%) and MAC (92.4%), respectively. Thus, optimized conditions for the surveillance of E. albertii contamination in food and investigations of E. albertii outbreaks, including the infectious dose, were clarified.

The 16s rFWA genes of Japanese Coxiella isolates obtained from various sources and geographical areas were directly sequenced by dideoxynucleotide chain termination methods in which Taq DNA polymerase was used. The levels of sequence similarity among Japanese, European, and American isolates were more than 99%, and the Japanese isolates were identified as Coxiella burnetii. C. burnetii strains isolated worldwide, including Japan, were found to be very similar.