Distribution of Van Genes of Vancomycin-resistant Enterococcus Isolated from Broilers in Peninsular Malaysia

Introduction Since first isolated in 1986 in Europe (1) vancomycin-resistant enterococcus (VRE) have emerged as a major nosocomial pathogen. Since then, VRE have been reported at an increasing number in countries outside Europe and the USA, such as in Singapore (2), Japan (3), Australia (4), and Korea (5). VRE is also a concern in Malaysia, however cases of VRE in human hospitals are uncommon (6, 7). Collective evidence from various works suggests that food animals such as poultry, is the reservoir of the organism. However, In Malaysia, Ong et al. (2002) showed that different species of VRE in Malaysia poultry wet markets are present at low rate (2.0%). Radu et al. (2001) recorded the occurrence of the vanA and vanC2/C3 genes in Enterococcus species from poultry sources in wet market. Epidemiological study by Hassan et al., (2006) documented a prevalence of 43.8% in broiler poultry including day-old chicks. VRE in poultry has been the concern to many export poultry and duck farmers in Malaysia since the link between poultry and VRE in humans was suggested. Currently Malaysia is under pressure to produce and export VRE-free chickens and thus incur additional costs from VRE screening procedures and disposal of positives produce. In 1999, it was estimated that more than 90% of export farms were suspended from exporting poultry and poultry products to Singapore (11, 12). No VRE has been reported in Singapore medical centers and a small VRE outbreak resulting from an imported case occurred once, but was reported to be easily controlled (13). Up till the present, evidence that prove VRE in animals directly causes disease in humans has not been conclusive. Information on VRE in Malaysia is scanty. The present study was initiated as part of a larger study with the long-term aim to establish the relationship between VRE found in animals to that in humans in Malaysia. The study will determine the distribution of vancomycin resistant genes among the broiler chicken isolates and establish the minimum inhibitory concentration (MIC) of vancomycin among the isolates.