An outbreak of community-associated methicillin-resistant Staphylococcus aureus infection in a boarding school in Hong Kong Special Administrative Region (China).

Mui-Ling Wong,Sik-On Pak,Shuk-Kwan Chuang,Lai-Key Kwok,Kwok-Ming Poon,Yuen-Kong Wan

doi:10.5365/wpsar.2013.4.4.005

Abstract

In November 2012, an outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections affecting students at a boarding school in Hong Kong Special Administrative Region (China) was detected. A case was defined as any student or staff notified with MRSA infection from 25 October 2012 to 5 July 2013 with the clinical isolate being of staphylococcal cassette chromosome mec type IV or V and positive for Panton-Valentine leukocidin gene. We conducted field investigations, advised on control measures and enhanced surveillance for skin and soft tissue infections at the school. Decolonization therapies were offered to all cases and contacts, and carrier screening was conducted. There were five cases; two (40%) were hospitalized and three (60%) required surgical treatments. Initial screening comprised 240 students and 81 staff members. Overall, four cases (80%) plus eight other students (3.3%) were carriers, with eight of 12 (66.7%) from the same dormitory. All staff members screened negative. After intensified control measures, the number of students screened positive for CA-MRSA decreased from nine to one with no more cases identified in the school. Identification of carriers, decolonization therapy, monitoring of cases and contacts and strengthening of environmental and personal hygiene were control measures that helped contain this CA-MRSA outbreak in a boarding school in Hong Kong Special Administrative Region (China).

Highlights

In November 2012, an outbreak of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections affecting students at a boarding school in Hong Kong (China) was detected
We reported a CA-MRSA outbreak affecting five students in a boarding school in which two (40%) were hospitalized and three (60%) required surgical treatment; this was the largest institutional CA-MRSA outbreak recorded in Hong Kong (China)
Supervised decolonization therapy was adopted as part of intensified measures together with reinforcement of environmental and personal hygiene control

Summary

Methods

A case was defined as any student or staff notified with MRSA infection from 25 October 2012 to 5 July 2013 with the clinical isolate being of staphylococcal cassette chromosome mec type IV or V and positive for Panton-Valentine leukocidin gene. A case was defined as any student or staff member of School X who was notified with SSTIs (e.g. boil, abscess and pustule) or other infections (e.g. pneumonia, sepsis) from 25 October 2012 to 5 July 2013, with MRSA isolated from any clinical specimen with the isolate being of staphylococcal cassette chromosome mec (SCCmec) type IV or V and positive for Panton-Valentine leukocidin (PVL) gene. A carrier was any student or staff member of School X, without a clinical infection, who had MRSA isolated from any screening specimen collected from 25 October 2012 to 5 July 2013 with the isolate being of SCCmec type IV or V and positive for PVL gene. Attack rates (AR%) by dormitory were calculated by dividing the number of cases and carriers identified by the total number of students in the dormitory, assuming the total number remaining constant during the investigation period

Results

Discussion

Conclusion