By investigating thein vitroactivity of 21 antimicrobial agents that are commonly available for veterinary use against 303 Japanese isoletes ofActinobacillus pleuropneumoniaecollected between 1986-1987 (178 strains) and 1999-2000 (125 strains), the authors compared the susceptibility of strains isolated in different years to the drugs examined. The resistant frequencies of the recent isolates were increased in (P<0.01, χ2test): PCG (change of resistance rate: 1.1%→13.6%), AMPC (1.1%→12.0%), ASPC (1.1%→12.0%), OTC (5.6%→44.8%), CP (1.1%→27.2%) and TP (1.7%→30.4%), which are used mainly for the treatment of disease caused byActinobacillus pleuropneumoniae. In addition, among recent isolates, two of 24 strains typed into serotype 1 were resistant to fluoroquinolones, and one of 76 strains of serotype 2 was resistant to macrolides. Most of the recent isolates were highly susceptible to CTF, FF and fluoroquinolones.
Strains of Salmonella Typhimurium (ST) isolated from cattle on 14 farms in Fukushima Prefecture between 1992 and 2004 were analyzed using molecular epidemiological techniques. There were six kinds of ST drug resistance patterns. The experimental results suggested the possibility that the DT104 strains showed resistance to ampicillin (A), chloramphenicol (C), streptomycin (S), sulfonamides (Su) and tetracycline (T), to ASSuT, and to nalidixic acid (N) added to ACSSuT. One amino acid substitution was identified in GyrA of the N-resistant strain. The ACSSuT kanamycin (K) resistant strain was plasmid (170kbp) mediated drug resistant. The ASSuTK-resistant strain possessed a plasmid (120kbp) closely related to an ST pathogenic plasmid, and the PFGE type also differed greatly from that of the other strains. As 13 or 14 strains exhibited a resistance to four or more drugs, it is necessary, from the point of view of both animal health and public health, to monitor the acquisition of new drug resistance in ST.
A seven-year-old, male golden retriever suddenly developed bilateral hind limb paralysis. The paralytic condition progressed for almost three months until the dog ultimately died. Pathologically, multiple foci of chronic non-purulent meningoencephalomyelitis with protozoan cysts and/or pseudocysts were widely formed in the CNS, especially in the cerebellum and brainstem. Non-purulent myositis with cysts was also formed in some muscles. The parasites in the cysts were clearly positive forN. caninumimmunohistochemically, and characteristic ultrastructures ofN. caninumwere observed by electron microscopy. The specific band that relates toN. caninumwas detected by nested PCR. The base composition of the DNA products resulted in 98.2% homology with that of N. caninum. From these results, the dog was confirmed to be the first case ofN. caninuminfection seen in an adult dog in Japan.
To evaluate useful markers for estimating somatic cell counts (SCC) in bulk milk, electronic conductivity (EC), N-acetyl-β-D-glucosaminidase (NAGase) activity, lactate dehydrogenase (LDH) activity, chemiluminescence (CL) units, adenosine triphosphate (ATP) levels and lactoferrin (Lf) concentrations in milk were measured for comparison with their SCC values. The SCC values correlated significantly (P<0.05, 0.01) with both the CL and LDH values. The measurement of ATP in milk appears to have application in estimating SCC levels in bulk milk.