background:Rheumatoid arthritis is a chronic inflammatory disease whose cause has not been fully elucidated. However,

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.

Introduction: Citrobacter spp. is an opportunistic bacteria that have been recognized as significant pathogens in patients with underlying diseases or immunocompromised status. The aim of this study was to identify extended-spectrum β-lactamases in clinical isolates of Citrobacter spp. Methods: This cross-sectional study was conducted at Hospital Central “Dr. Ignacio Morones Prieto” in San Luis Potosi, Mexico. Nineteen isolates of Citrobacter spp. were obtained from clinical specimens between April to December 2015. Four isolates were resistant to third-generation cephalosporins. The presence of genes encoding ESBL ( blaCTX-M-15, blaTEM-1, blaVEB-1, blaSHV, and blaPER-1) was analyzed by PCR. For this purpose, plasmid DNA was extracted and horizontally transferred to recipient E. coli Top 10. Results: blaCTX-M-15 and blaVEB-1 genes were detected in Citrobacter freundii and Citrobacter sedlakii, whereas blaPER-1 gene was identified in 1 isolate of Citrobacter freundii. In contrast, blaSHV gene was not detected in any isolate. One strain carried blaCTX-M-15, blaTEM-1, blaVEB-1, and blaPER-1 genes, most in a 275-kb plasmid. Conclusion: This study shows the presence of different types of ESBL in clinical isolates of Citrobacter freundii and Citrobacter sedlakii, which confer resistance to broad-spectrum β-lactams. The plasmid identified in this study harboring ESBL genes could play an important role in the dissemination of antibiotic resistance.

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.