Arcanobacterium pyogenes is commonly isolated from ruminant animals as an opportunistic pathogen that co-infects with other bacteria, normally causing surface or internal abscesses. Twenty-eight strains of A. pyogenes isolated from forest musk deer suppurative samples were identified by their 16S rRNA gene sequences, and confirmed by amplification of the pyolysinencoding gene (plo) in all isolates. The MICs of 14 commonly used antibiotics were determined by an agar dilution method. Class 1 and 2 intI genes were amplified to determine whether integrons were present in the A. pyogenes genome. Class 1 gene cassettes were detected by specific primers and analysed by sequencing. All of the strains were susceptible to most fluoroquinolone antibiotics; however, high resistance rates were observed for b-lactams and trimethoprim. A total of 18 of the isolates (64.3 %) were positive for the class 1 intI gene, and 16 (57.1 %) contained class 1 gene cassettes with the aacC, aadA1, aadA2, blaP1 and dfr2a genes. Most were present in the multi-resistant isolates, indicating a general concordance between the presence of gene cassettes and antibiotic resistance, and that the integrons have played an important role in the dissemination of antimicrobial resistance in this species.
INTRODUCTIONForest musk deer (Moschus berezovskii) are solitary ruminants encountered mainly in South-West China. The musk secreted by the deer is a traditional and precious Chinese medicine, and is also used in the manufacture of perfumes. As a result of the decreasing population size, all forest musk deer species were categorized as first-class key species of wildlife protected by Chinese legislation in 2002 (Chen et al., 2007;Guha et al., 2007;Guan et al., 2009). Artificial breeding of forest musk deer started in the 1950s, and diseases were the most significant restriction factor preventing a population increase (Lu et al., 2009). In Miyaluo Farm (Sichuan Province, China), every eight to ten forest musk deer are fed in one fold of about 200 m 2 due to the timid and leaping character of these animals, which means that they easily hurt themselves. Dyspepsia, pneumonia, metritis, urinary stones and abscesses are common diseases of forest musk deer here, and abscesses in particular have cause hundreds of deaths. Antibiotics have been used here for over 15 years, but due to the previous negligent management where drug abuse was prevalent and the dose was always on the high side, resistance has developed, meaning that many of the drugs have become useless against some of the pathogenic infections.Arcanobacterium pyogenes is considered an important opportunistic pathogen of the upper respiratory tract and in puerperal uterine infections of cattle, sheep, swine, birds, humans and many other species (Nattermann & Horsch, 1977;Queen et al., 1994;Narayanan et al., 1998;Silva et al., 2008). It was recently reclassified from the genus Actinomyces on the basis of the rRNA gene sequence (Pascual Ramos et al., 1997). The organisms enter the blood stream and interact...