RESUMEN

Biennial H1N1pdm09 influenza A virus (IAV) epidemics have been associated with major severity of respiratory disease in Mexico. Atypically and in contrast with what happened in USA, Canada and Europe during 2017, an increase of infections due to the H1N1pdm09 pandemic virus instead of H3N2 was observed. In order to determine the viral contribution to severe acute respiratory disease, we characterized the pathogenicity determinants of IAV in Mexico during the 2015-2016 and 2016-2017 seasons. The RNA segments of 20 IAV samples were sequenced by NGS platform and phylogenetic analysis was conducted. The analysis of the hemagglutinin (HA) sequences established that all virus samples, except one, belong to clade (6B.1). The IAVs presented the substitution S162 N, which introduces a new glycosylation site in the hemagglutinin. We also found the D222 G substitution, which has been associated with a higher tropism towards the lower respiratory tract, and a non-reported insertion of one Ile in NS1 (Ile113). The IAVs from 2016 to 2017 in Mexico belong to the new clade 6B.1. The new glycosylation site in HA (S162 N) is a major change that may affect the efficacy of the current vaccine. We detected in several patients pathogenicity determinants associated with the severity of the respiratory disease.

Asunto(s)

Sustitución de Aminoácidos , Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Subtipo H1N1 del Virus de la Influenza A/genética , Gripe Humana/epidemiología , Gripe Humana/virología , Adolescente , Adulto , Anciano , Secuencia de Aminoácidos , Niño , Preescolar , Comorbilidad , Femenino , Glicoproteínas Hemaglutininas del Virus de la Influenza/química , Historia del Siglo XXI , Humanos , Lactante , Recién Nacido , Subtipo H1N1 del Virus de la Influenza A/clasificación , Gripe Humana/diagnóstico , Masculino , México/epidemiología , Persona de Mediana Edad , Modelos Moleculares , Filogenia , Estaciones del Año , Relación Estructura-Actividad , Evaluación de Síntomas , Adulto Joven

RESUMEN

Introduction: Healthcare-associated infections are an important cause of morbidity and mortality, are among the most common adverse events in healthcare, and of them, pneumonia is the most commonly reported. Our objective was to evaluate the incidence and clinical outcome of respiratory viruses in hospital-acquired pneumonia (HAP). Methods: This was a prospective cohort study, include patients aged between 0 and 18 who fulfilled Centers for Diseases Control and Prevention (CDC) criteria for HAP. Demographic and clinical data were obtained, and a nasopharyngeal swab specimen was taken for the detection of respiratory viruses. All included patients were monitored until discharge to collect data on the need for mechanical ventilation, intensive care unit (ICU) admission, and mortality. All-cause 30-day mortality was also ascertained. Results: Four thousand three hundred twenty-seven patients were followed for 42,658 patient-days and 5,150 ventilator-days. Eighty-eight patients (2.03%) met the CDC criteria for HAP, 63 patients were included, and clinical and epidemiological characteristics showed no statistically significant differences between patients with virus associated healthcare-associated pneumonia (VAHAP) and those with non-viral healthcare-associated pneumonia (NVHAP). At least one respiratory virus was detected in 65% [95% CI (53-77)] of episodes of HAP, with a single viral pathogen observed in 53.9% and coinfection with 2 viruses in 11.1% of cases. The outcome in terms of ICU admission, mechanical ventilation and the 30-day mortality did not show a significant difference between groups. Conclusions: In two-thirds of the patients a respiratory virus was identified. There was no difference in mortality or the rest of the clinical outcome variables. About half of the patients required mechanical ventilation and 10% died, which emphasizes the importance of considering these pathogens in nosocomial infections, since their identification can influence the decrease in hospital costs and be taken into account in infection control policies.