We analyzed 108 strains of pathogenic Escherichia coli isolated from diseased swine (sampled from 63 farms, 96 cases and 103 individuals) in Ibaraki Prefecture, Japan, between 2006 and 2014. The O serogroups of the 108 strains were determined using the agglutination test and the predominant serogroups were found to be O116 (34.3%), O139 (11.3%) and O149 (9.3%). The results of antimicrobial susceptibility testing showed that the O116 strains were resistant to many antimicrobials (12.7 on an average; 19 maximum), whereas strains O139 and O149 exhibited resistance to a lower number of antimicrobials (6.6 and 7.3 on average, respectively). Surprisingly, all O116 strains were resistant to fluoroquinolones. Most of the O116 strains showed epidemiologically unrelated PFGE patterns and there is no relation between the isolation of fluoroquinolone-resistant O116 and the use of fluoroquinolones on the farm as a result of a hearing investigation. In this study, we demonstrated that O116 is a multidrug-resistant serogroup that can pose a threat to livestock production. Selective use of antimicrobials and detailed epidemiological studies are required to prevent further dissemination of O116 strains on farms.
We evaluated the incidence of porcine circovirus type 2 (PCV2) by conventional PCR in 163 serum samples which were pooled at each stage of 530 healthy pigs from 21 farms in Japan in 2015. Subsequent sequence analysis of the open reading frame 2 region of the PCV2 DNA (702 or 705 bp) from the PCR products showed that seven different PCV2 strains were present. Four PCV2 strains (from three farms in Kanagawa Prefecture and one in Hiroshima Prefecture) belonged to genotype PCV2a, while three (from one farm in Aomori Prefecture and two in Chiba Prefecture) belonged to the PCV2d group. Moreover, the PCV2d strains were closely related to the mPCV2 strain described as a rapidly proliferating strain in the U.S. in 2012, but not to the Japanese strains reported among PCV2d in 2008. In conclusion, it is probable that the dominance of PCV2 strains change with the progression of time in Japan.
In order to gain indirect insight into steroid hormone metabolism in the liver of dairy cattle with fatty liver syndrome, the concentration of estrogen and cortisol in the bile was measured from cattle with a fatty liver and cattle with a normal liver. Livers and bile were taken from 128 slaughtered Holstein dairy cows. Animals with less than a 10% deposit of fat in the liver were categorized as the normal liver group (n=56), those with at least 10% but less than 30% were categorized as the mild fatty liver group (n=41), and those with 30% or more were categorized as the severe fatty liver group (n=31). Comparison of the normal liver group and fatty liver groups indicated that the values for the three estrogen fractions in the bile showed the highest concentrations in the severe fatty liver group, and that the concentrations were the lowest in the normal liver group. The severe fatty liver group showed high values for cortisol in the bile. The present study confirmed that the steroid hormone concentration in the bile was affected by the severity of fatty liver syndrome in dairy cows.
Oral spirochetes existed in dental plaque and could be clearly distinguished by their characteristic morphology and motility using a phase-contrast or dark-field microscope. Oral spirochetes are considered to be periodontal disease bacteria in dogs. In this study, 33 dogs (average age 8.4 years) suffering from periodontal disease were treated with Azithromycin by oral administration for 7 days. The dental plaque was observed using a phase-contrast microscope and the clinical effect was evaluated. As a result, a decrease in oral spirochetes was shown in this experiment. The results for gingivitis, adhesion of dental plaque and halitosis were improved after medication relative to before medication. These results indicated that treatment with Azithromycin for periodontitis caused by oral spirochetes had a significant effect.