Background: Staphylococcus aureus is a leading cause of broad-spectrum infections both in the community and within healthcare settings. Methicillin-resistant Staphylococcus aureus (MRSA) has become a global public health issue. The aim of this study was to examine the clinical and molecular characteristics of Staphylococcus aureus isolates and to define the population structure and distribution of major MRSA clones isolated in a tertiary-care hospital in Mexico. Results: From April 2017 to April 2018, 191 Staphylococcus aureus isolates were collected. The frequency of MRSA was 26.7%; these strains exhibited resistance to clindamycin (84.3%), erythromycin (86.2%), levofloxacin (80.3%), and ciprofloxacin (86.3%). The majority of MRSA strains harbored the SCCmec type II (76.4%) and t895 (56.8%) and t9364 (11.7%) were the most common spa types in both hospital-associated MRSA and community-associated MRSA isolates. ST5-MRSA-II-t895 (New York /Japan clone) and ST1011-MRSA-II-t9364 (New York /Japan-Mexican Variant clone) were the most frequently identified clones. Furthermore, different lineages of Clonal Complexes 5 (85.4%) and 8 (8.3%) were predominantly identified in this study. Conclusion: Our study provides valuable information about the epidemiology of MRSA in a city of the central region of Mexico, and this is the first report on the association between t895 and t9364 spa types and ST5 and ST1011 lineages, respectively. These findings support the importance of permanent surveillance of MRSA aimed to detect the evolutionary changes of the endemic clones and the emergence of new strains.

BACKGROUND Staphylococcus aureus is a leading cause of broad-spectrum infections both, in the community and within the healthcare settings. The methicillin-resistant Staphylococcus aureus (MRSA) variant has became a global issue of public health. The aim of this study was to examine the clinical and molecular characteristics of Staphylococcus aureus isolates and to define the population structure and distribution of major MRSA clones present in a tertiary-care hospital in Mexico. RESULTS From April 2017 to April 2018, 191 isolates of Staphylococcus aureus were collected. The frequency of MRSA was 26.7%, these strains exhibited resistance to clindamycin (85.3%), erythromycin (86.2%), levofloxacin (80.3%), and ciprofloxacin (86.3%). The majority of MRSA strains harbored the SCCmec type II (39/51); the t895 (29/51) and t9364 (6/51) were the most common spa types in both, hospital-associated MRSA and community associated MRSA isolates. The clones ST5-MRSA-II-t895 (New York /Japan clone) and ST1011-MRSA-II-t9364 (New York /Japan-Mexican Variant clone) were the most frequent. Finally, different lineages of Clonal Complex 5 (90.6%) and Clonal Complex 8 (9.1%) were identified in this study. CONCLUSION Our study provides valuable information about the epidemiology of MRSA in a city of the central region of Mexico, and this is the first report on the association between the t895 and t9364 spa types and the ST5 and ST1011 lineages, respectively.