Determinación de carga bacteriana y detección de bacterias con potencial patogénico a partir de muestras de filtros de aire acondicionado recolectadas en ambientes domésticos del noreste de México

Airborne pathogens can adversely affect human health not solely through infections but causing allergic responses or toxic effects. These microorganisms can find an ideal environment for growing in air conditioning units, and although innovations for cleaner and healthier airflow is available, users in developing countries have older models or lack of an adequate cleaning routine of the filters employed, which presents a health hazard for vulnerable populations, spending long periods of time in climatized environments. Therefore, our objective was to detect by microbiological and molecular methods the presence of pathogens in filter samples collected in Tamaulipas, Mexico. Our findings exhibit a mean bacterial load surpassing the 2,300,000 CFU (colony forming units)/g, evidence of β-hemolysis in more than 20% of blood agar cultures, growth in selective media for Staphylococcus sp. and members of the Enterobacteriaceae family in over 50% of samples, the latter confirmed by molecular assays, which also showed a low prevalence of genes related to antibiotic resistance. These results indicate that accumulated dust in air conditioning grid filters can effectively serve as reservoir for bacteria with pathogenic characteristics.