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.