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Landscape Ecology - In March of 2011 a huge tsunami devastated forest habitats along the coast of Sendai Bay in northeastern Japan. Evaluation and monitoring of the changes in habitat connectivity... 相似文献
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Ozaki H Esaki H Takemoto K Ikeda A Nakatani Y Someya A Hirayama N Murase T 《Veterinary microbiology》2011,150(1-2):132-139
To investigate the effects of rearing practices of commercial broiler chickens on the incidence of antimicrobial resistance in commensal Escherichia coli isolates, fecal E. coli isolates obtained in 4 farms were screened for anitimicrobial resistance. Ten E. coli isolates were recovered from each of the fecal samples collected from 10 birds in the farms at the ages of 2 days, 14-17 days, and 47-50 days. In 2 out of the 4 farms, no antimicrobials were used during the rearing period. In the other two farms, following collection of the fecal samples at 14 and 15 days of age, oxytetracycline (OTC), sulfadimethoxine (SDMX), and tylosin were given to birds on one farm and SDMX was used in the other. Isolates resistant to ampicillin and OTC that were obtained from an untreated flock at different sampling times were closely related to each other by pulsed-field gel electrophoresis patterns (PFGE) of XbaI-digested chromosomal DNA. PFGE analysis together with in vitro conjugation experiments suggested that diversity of resistance phenotypes within a clone may be resulted from the acquisition and loss of R-plasmids in an untreated and a treated flock. The numbers of resistance phenotypes observed among fecal isolates increased during the growth of the chickens in all the farms. The results in the present study suggest that persistence of commensal E. coli strains resistant to antimicrobials even in the absence of antimicrobial administration. It is also hypothesized that horizontal transmission of resistance determinants resulted in the emergence of different resistance phenotypes in those farms. 相似文献
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Asai T Esaki H Kojima A Ishihara K Tamura Y Takahashi T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2006,68(8):881-884
Antimicrobial susceptibility of 183 Salmonella isolates from apparently healthy food-producing animals obtained during the period from 2000 to 2003 throughout Japan was examined. Of 29 serovars identified, Salmonella Infantis (37.7%) was the most prevalent, followed by S. Typhimurium (19.7%). Salmonella bacteria resistant to dihydrostreptomycin (77.6%) were about 10% more prevalent than those resistant to oxytetracycline (67.8%), though the nation-level veterinary use of tetracycline antibiotics is much greater than that of streptomycin in Japan. In seventeen isolates (9.3%) resistant to nalidixic acid, single point mutations were detected at 84 or 87 in the quinolone resistance-determining region of the gyrA gene. 相似文献
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Esaki H Asai T Kojima A Ishihara K Morioka A Tamura Y Takahashi T 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(1):75-77
A total of 27 clinical isolates of Mannheimia haemolytica from cattle in Japan from 2001 to 2002 were examined for antimicrobial susceptibility to 25 antimicrobial agents. The minimum inhibitory concentrations of 25 different antimicrobials were determined by an agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards. Of the 27 isolates, seven isolates (26.9%) were resistant to at least one of the 25 drugs and resistance rates ranged from 3.7 to 18.5%. Resistance rates to dihydrostreptomycin (18.5%), oxytetracycline (11.1%), and doxycycline (11.1%) were relatively high and those to the remaining drugs were less than 10%. 相似文献
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