QuEChER method for air microbiological monitoring in hospital environments

Introduction: Nosocomial pathogens have become a priority issue for public health, since they are responsible for increased morbidity and mortality in hospitalized patients and the development of multi-resistant microorganisms, as well. Recent studies found strong evidence that airborne transmission plays a key role in many nosocomial infections. Thus, we aim to develop a QuEChER methodology for the characterization of airborne microbial levels, analyzing potential variables that modify the air microbiological load. Methodology: Particulate matter levels and suspended and settled bioaerosols were determined simultaneously employing optical sensors, Harvard impactors and settle plates, respectively. Environmental variables were also measured at different sites during different working shifts and seasons. Results: We found a straightforward relationship between airborne particles, air exchange rates, and people influx. Levels of suspended microorganisms were related to fine particulate matter concentration, CO2 and ambient temperature. A positive linear relationship (R2 = 0.9356) was also found between fine particulate matter and CO2 levels and air microbial load. Conclusion: The QuEChER methodology is an effective methodology that could be used to improve the surveillance of nosocomial pathogens in developing countries hospitals where air quality is scarcely controlled.