36 Hong Kong Med J ⎥ Volume 21 Number 6 (Supplement 7) ⎥ December 2015 ⎥ www.hkmj.org KEY MESSAGES 1. Tere is a high level of contamination of pig carcasses in Hong Kong with multi-drug resistant methicillin-resistant Staphylococcus aureus (MRSA) ST9. 2. Personnel occupationally exposed to pigs and pig carcasses are at risk of colonisation and possible infection. 3. Whilst the clinical signifcance of porcine MRSA ST9 is unclear, there is a need for continued surveillance of this potential reservoir of MRSA. 4. Butchers should be encouraged to wear gloves Prevalence of carriage and characterisation of methicillin-resistant Staphylococcus aureus in slaughter pigs and personnel exposed to pork carcasses MV Boost *, M O'Donoghue, L Guardabassi Introduction In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has emerged in the community. Tere have been increasing reports of MRSA colonisation of pigs and pig farmers in Europe 1 and North America. Multi-locus sequence typing (MLST) revealed widespread dissemination of a particular sequence type (ST) 398 among pigs in the Netherlands and subsequently the occurrence of this MRSA lineage has been reported in several other countries and animal species. Compelling microbiological and epidemiological evidence indicates that people who live or work on farms, especially pig farms, have an increased risk of colonisation or infection with ST398 MRSA. Human infection with ST398 MRSA has been reported in Hong Kong, but no information about occupation or pig contact was available. Porcine-associated MRSA ST398 typically harbours Staphylococcal cassette chromosome (SCC) mec type IV or V, but unlike most community MRSA, ST398 is increasingly multi-drug resistant. It appears that the genes for Panton-Valentine leucocidin toxin are rare in these strains. ST398 is non-typable by pulsed feld gel electrophoresis (PFGE) using the restriction endonuclease sma1, which is commonly used in the investigation of clonality of staphylococcal strains. Tis study aimed to (1) determine the MRSA colonisation level of locally slaughtered pigs and whether this colonisation results in spread to persons Hong Kong Med J 2015;21(Suppl 7):S36-40 RFCID project number: 08070912 1 MV Boost, 2 M O'Donoghue, 3 L Guardabassi 1 Department of Health Technology & Informatics, The Hong Kong Polytechnic University 2 School of Nursing, The Hong Kong Polytechnic University 3 Faculty of Life Sciences, University of Copenhagen, Denmark * Principal applicant and corresponding author: htmboost@polyu.edu.hk occupationally exposed, (2) characterise any MRSA isolates for the presence of toxin mediating genes, and (3) compare ST398 MRSA strain in this locality with the predominant strain reported elsewhere. Methods Tis study was conducted from January 2009 to December 2012. Ethics approval was obtained from the Human Subjects Ethics Sub-Committee of Te Hong Kong Polytechnic University. Nasal samples were collected from 400 slaughtered pigs after distribution to three wet markets in Hong Kong over a 3-month period. Butchers at all major wet markets in Hong Kong were invited to participate. A total of 300 butchers consented to sampling by self-collection of a nasal swab according to instructions. Butchers were asked about any recent hospitalisation, healthcare workers in the family, wound infections within the last year, and antibiotic use in the last 6 months. Nasal swabs were collected from 100 to 150 pigs of diferent ages (weaning pigs, market ready animals, and breeding sows) from two farms each in Hong Kong (n=220) and Guangdong (n=255). A small number of environmental samples were collected at the Hong Kong farms. Swabs were enriched in brain heart infusion, cultured on selective agar and presumptive MRSA colonies were identifed as S aureus by latex agglutination. Susceptibility to a range of antibiotics was determined following standard guidelines. MRSA isolates were tested by PCR for the RESEARCH FUND FOR THE CONTROL OF INFECTIOUS DISEASES whilst working and maintain good personal hygiene to reduce colonisation risk.