MSSAClinical Isolates in the

TO THE EDITOR—We read with great inter-est the study by Uhlemann et al [1] reporting the emergence of methicillin-susceptibleStaphylococcus aureus (MSSA) clone sequence type (ST) 398 as a ma-jor community- and hospital-associated pathogen in theDominicanneighborhood ofnorthernManhattan.Theauthorsreport certain unique antimicrobial susceptibil-ity patterns among the 64 nonblood-stream ST398 MSSA isolates compared to controls (non-ST398 MSSA isolates). In this study, 97 % (62/64) of ST398 MSSA isolates were resistant to both erythromycin and clindamycin compared to 38 % of controls. Also, none of the ST398 MSSA isolates were resistant to tetracycline. Similar findings were report-ed in a French study of 17 ST398 MSSA strains isolated from bloodstream infec-tions [2]. In this study, 88.2 % (15/17) of ST398 MSSA strains were resistant to erythromycin compared to 8.7 % (52/ 598) of non-ST398 MSSA strains and none of these 17 strains were resistant to tetracycline. Several other studies report-ed a similar susceptibility pattern [3–5]. Assuming that this pattern of antimicro-bial susceptibility could be the pheno-typic expression of ST398 MSSA, we examined the national trends of MSSA susceptibility to erythromycin, clindamy-cin, and tetracycline using a large data-base of clinical isolates from across the United States. We used data for antimicrobial sus