To determine the prevalence of indicator bacteria resistant to antimicrobials among poultry in three Southeast Asian countries (Vietnam, Indonesia and Thailand), we examined the antimicrobial susceptibilities of commensal bacteria isolated from chickens. In total, 125, 117 and 180 isolates of Escherichia coli, Enterococcus faecalis and Enterococcus faecium, respectively, were used to test for antimicrobial susceptibility. Bacterial resistance to antimicrobial treatment was most frequently observed with oxytetracycline with a prevalence of 73.6% (E. coli), 69.2% (E. faecalis) and 92.2% (E. faecium). Resistance to fluoroquinolones, which are critically important medicines, was also frequently observed in E. coli (48.8%), E. faecalis (17.9%) and E. faecium (82.8%). The prevalence of indicator bacteria resistant to most of the antimicrobials tested in these countries was higher than those for developed countries. The factors underlying antimicrobial resistance may include inappropriate and/or excessive use of antimicrobials. These results highlight the need for monitoring the emergence and prevalence of antimicrobial resistance in developing countries.

In this study, we carried out experimental infections in cattle and goats using a foot-and-mouth disease virus (FMDV) isolate from the 2010 epidemic in Japan to analyze clinical manifestations, virus-shedding patterns and antibody responses in the animals. We found that the FMDV O/JPN/2010 isolate is virulent in cattle and goats, produces clinical signs, is spread efficiently by direct contact within the same species, and is persistently infectious in cattle. Quantitative analysis of levels of viral RNA in the tissues of cattle and goats infected with the isolate showed that the pharyngeal region is an important major target of the FMDV O/JPN/2010. Time course data of viral loads, excretion and transmission of the FMDV O/JPN/2010 in this study are key in providing quantitative data essential for epidemiological investigation and risk analysis in relation to disease controls.

ABSTRACT. In this study, we validated three commercial ELISA (NSP-ELISA) kits that detect antibodies to a nonstructural protein of footand-mouth disease virus (FMDV) in terms of their specificities and sensitivities. Although the specificities of the NSP-ELISA kits were as high as that of liquid-phase blocking ELISA (LPBE) in non-infected, non-vaccinated animals, the sensitivities of the NSP-ELISA kits were significantly lower than those of the present LPBE and did not agree with the findings of a previous report on infected animals in the field. Therefore, although countries can adopt both a "vaccination-to-kill" policy and a "vaccination-to-live" policy after emergency vaccination during an FMD epidemic, the NSP-ELISA kits do not seem to be suitable for the latter policy in Japan. These results should be useful for choosing appropriate control measures for potential future FMD epidemics in Japan and elsewhere.