Major article
Trial to control an outbreak of Panton-Valentine leukocidin–positive methicillin-resistant Staphylococcus aureus at a boarding school in Japan

https://doi.org/10.1016/j.ajic.2011.02.010Get rights and content

Background

Our retrospective investigation of methicillin-resistant Staphylococcus aureus (MRSA) infection at a hospital in Japan around 2007 suggested dissemination of community-associated MRSA (CA-MRSA) strains among healthy students in a Japanese boarding school, which frequently caused skin disease and exhibited the same antibiogram patterns.

Methods

Active surveillance of skin diseases for 6 months after May 2008, examination of MRSA carriage in selected high-risk groups, and investigation of their life circumstances, including environmental cultures, were conducted in the school. Furthermore, we strengthened hygiene practices and improved recognized risk factors from November 2008 and observed the occurrence of skin diseases and MRSA carriage rate for the evaluation of infection controls.

Results

We identified 21 patients with skin diseases in whom MRSA strains were isolated. MRSA colonization rates in 3 selected groups ranged from 7.6% to 36.6%. The rates of both skin disease and MRSA carriage decreased significantly after infection controls were introduced. Genetic analysis revealed a main dissemination of a PVL-positive SCCmec IVc clone (41/47 isolates in total), presenting as a different pulsed-field type than USA300.

Conclusion

This first report of a PVL-positive CA-MRSA outbreak in Japan demonstrates systematic management of dissemination by conducting surveillance in a closed community.

Section snippets

Population characteristics

We surveyed a 3-year boarding high school in Japan, attended by approximately 700 healthy students aged 15-19 years and staffed by approximately 300 teachers and other staff members. The students live and work closely together, and sometimes experience skin abrasions from participating in regular training and sports clubs, such as rugby, martial arts, and baseball. Students or staff who become ill usually visit a clinic within the school. But because the clinic does not provide detailed

Active surveillance and clinical features of SSTI patients at the boarding school

During active surveillance of the school between May and October 2008, we identified 21 individuals with an SSTI (all males, with no past history of recent hospitalization), including 19 students, 1 teacher (case 8), and 1 other staff member (case 16). MRSA strains were isolated from all 21 individuals. The incidence of MRSA causing SSTIs was calculated as 32.4 per 1,000 outpatients during the period (21 MRSA cases per 649 outpatients from the school) and was considered an outbreak. The

Discussion

We report an outbreak of a PVL-positive MRSA clone in a boarding school and a prospective follow-up study aimed at reducing the prevalence. Our original hypothesis, based on retrospective investigation of MRSA strain antibiograms, suggested dissemination of the same CA-MRSA strains. Active surveillance and examination of MRSA carriage in the school proved this dissemination. Systematic measures were then implemented to suppress the outbreak. This is a first report of systematic management of a

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This work was supported in part by a grant from the Japan Ministry of Defense and a Grant-in-Aid (S0991013) from the Ministry of Education, Culture, Sport, Science, and Technology, Japan for the Foundation of Strategic Research Projects in Private Universities. The views expressed in this article are those of the authors and do not reflect the official policies of the Japan Ministry of Defense or the Japan Self-Defense Forces.

Conflict of interest: None to report.

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Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.