The changes of MRSA infections in chronic suppurative otitis media.

OBJECTIVES

To investigate the epidemiologic and microbiological characteristics of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) infections in the otorrhea of chronic suppurative otitis media (COM) patients.

DESIGN

Retrospective study of patients with newly identified MRSA infections from January 1998 through December 2006. A total of 2773 patients with a diagnosis of COM were included in this study. An antibiotic sensitivity test was performed for each isolate.

RESULTS

The prevalence of MRSA in COM was 4.9 percent (137 of 2773 patients). The proportion of CA-MRSA rose from 0.7 percent in 1998 to 11.4 percent in 2006. However, the proportion of HA-MRSA did not change significantly, from 0.7 percent in 1999 to 1.3 percent in 2006. All of the CA-MRSA strains identified in our study were susceptible to trimethoprim/sulfamethoxazole (TMP/SMX). Rifampin susceptibility was also noted in 90 percent of the cases.

CONCLUSIONS

CA-MRSA infections have risen dramatically in the past decade. CA-MRSA and HA-MRSA in COM differed in both clinical and microbiological aspects.