Nasal swabs of 293 calves were examined for Mycoplasma. The samples were collected from calves affected with respiratory diseases on 71 farms in various parts of Japan between 1996 and 1997. Mycoplasma bovirhinis was isolated from 47 of 293 calves (16.0%). Mycoplasma alkalescens, M. bovis, M. arginini, M. bovigenitalium and Acholeplasma spp. were isolated from 19 (6.5%), seven (2.4%), four (1.4%), four (1.4%) and 18 (6.1%) calves, respectively. Pasteurella multocida and P. haemolytica were isolated from 60% of Mycoplasma-positive calves. However, other bacteria were not isolated from calves. To evaluate the antimicrobial susceptibility of their isolates, 68 M. bovirhinis, 21 M. alkalescens and 10 M. bovis strains were examined for 12 antimicrobial agents. All isolates showed higher susceptibility to tiamulin than to the other drugs used in the study. However, erythromycin had no effect on any of the Mycoplasma strains studied. The field isolates were less susceptible than the type strains to some drugs, such as spiramycin, oxytetracycline and tylosin.
Staphylococcus pseudintermedius strains were isolated from healthy dogs and dogs with pyoderma in 2000-2002 and 2009. All the isolates from dogs with pyoderma in 1999-2000 and from healthy dogs in 2000-2002 and 2009 were susceptible to cefalexin and/or other cephalosporins and oxacillin. However, 7.1-12.5 and 11.4% of S. pseudintermedius isolates from dogs with pyoderma in 2009 were resistant to cephalosporins and oxacillin, respectively. All S. pseudintermedius isolates from dogs with pyoderma in 1999-2000 and those from healthy dogs in 2000-2002 were susceptible to fluoroquinolones; however, 50% of the S. pseudintermedius strains isolated from dogs with pyoderma in 2009 and 30% of the S. pseudintermedius strains isolated from healthy dogs in 2009 were resistant to fluoroquinolones. Of the 21 oxacillin-resistant S. pseudintermedius (MRSP) isolates, 11 carried SCCmec type V and 10 carried hybrid SCCmec types II-III. Staphylococcus pseudintermedius strains that were resistant to only one of three fluoroquinolones had a mutation in the quinolone resistance determination region of grlA, whereas S. pseudintermedius strains that were resistant to two or more fluoroquinolones had mutations in the quinolone resistance determination regions of both grlA and gyrA.
We previously reported the isolation of an exfoliative toxin from culture filtrates of Staphylococcus hyicus (shET) and reproduction of exfoliation in piglets injected with partially purified shET. In this study, we purified shET and compared the biological and physicochemical properties of shET and Staphylococcus aureus exfoliative toxin (sETA and sETB). shET was purified by ammonium sulfate precipitation, DEAE-celulofine A-500 column chromatography, Sephadex G-75 gel filtration, and polyacrylamide gel electrophoresis (7.5% polyacrylamide). Purified shET (p-shET) did not cause exfoliation of the epidermis in suckling mice but did cause exfoliation in 1-day-old chickens, whereas sETA and sETB produced by S. aureus caused exfoliation in suckling mice but not in 1-day-old chickens. The molecular mass of p-shET was determined as 27 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. p-shET did not show any cross-reactivity with sETA and sETB in Western immunoblotting analysis or the immunodiffusion test.
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