High prevalence of t895 and t9364 spa types of methicillin-resistant Staphylococcus aureus in a tertiary-care hospital in Mexico: different lineages of clonal complex 5.

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.

Complete Genome Sequence of Human Coronavirus OC43 Isolated from Mexico.

We report the complete genome sequence of the first Mexican human coronavirus (HCoV) OC43, obtained by new-generation sequencing and a metagenomic approach, isolated from a child hospitalized with pneumonia. The genome is closely related to the other OC43 genome sequences available, ranging from 99.8% to 98.2% nucleotide sequence identity.

NKG2C gene deletion in the Mexican population and lack of association to respiratory viral infections.

Expansion of a natural killer (NK) cell population that expresses NKG2C has been associated with cytomegalovirus and other viral infections. It has been suggested that this cell population may play a role in infection control. Deletion of the NKG2C gene (homozygous or heterozygous) has been reported with high prevalence in European and Asian populations. However, the effect of NKG2C genotype on NK cell responses to infection remains poorly defined. We determined the prevalence of the NKG2C deletion in a Mexican population (n = 300) and in a group of patients (n = 131) to assess whether NKG2C genotype affects the incidence of symptomatic viral infections caused by influenza or respiratory syncytial virus. The frequency of the NKG2C deletion haplotype in Mexican mestizos was significantly lower (10.3%) than that reported in other populations (17.5-21.9%). No difference in the prevalence of NKG2C deletion was observed in subjects with viral infections compared with the reference population. In addition, no differences in clinical characteristics and infection outcome were observed between patients with and without the NKG2C gene deletion. Our results indicate that copy number variation in the NKG2C gene has no impact on the severity of respiratory viral infections.