Even in climate-controlled health care units, the outside temperature can influence the indoor temperature, and these changes may impact the incidence of multidrug-resistant organisms, or MRDOs, researchers reported in Infection Control & Hospital Epidemiology.
“It remains unclear why seasonality and associations with high temperatures are detected even in hospitals or hospital units with climate control,” Dayanna Conislla Limaylla, MSc, from the post-graduate program in collective health at São Paulo State University, and colleagues wrote. “To fill these gaps in our knowledge, we conducted a prospective ecological study in a teaching hospital in Brazil.”
According to the authors, the hospital is located in a tropical climate and was originally built as a tuberculosis sanatorium, with wide windows that open to the outside and high ceilings. Only the five ICUs in the hospital have climate control, the researchers reported.
Between July 2017 and June 2018, Limaylla and colleagues measured the inside temperature and relative humidity in 15 non-climate-controlled wards and one medical-surgical ICU containing 11 beds. They also monitored the incidence of health care-associated multidrug-resistant pathogens, including gram-positive organisms like MRSA and vancomycin-resistant Enterococci (VRE), and gram-negative organisms like carbapenem-resistant Enterobacteriaceae, Acinetobacter baumanni and Pseudomonas aeruginosa.
According to Limaylla and colleagues, the findings demonstrated a negative association between humidity and overall MDROs and gram-negative pathogens in units without climate control, and a positive association between temperature and overall MDROs, overall gram-positive pathogens, VRE and P. aeruginosa in the climate-controlled ICU.
In the ICU, the median daily temperature was 72°F and varied only slightly, with a range of 67.3° to 74.8° — indicating that the incidence of MDROs is affected by even small increases in temperature, the researchers said.
In the wards without climate control, the median daily temperature was higher than the ICU wards at 76.6°F, with a larger range of 64.9° to 85.1°. Limaylla and colleagues reported that the temperature did not have a detectable impact on the incidence of MDROs in the non-climate-controlled wards.
“Even though this finding contradicts previous findings of our group, the smaller incidence of MDROs in the 15 wards, due both to less vulnerable patients and because we did not perform an active search using surveillance cultures, may have hindered the statistical power of our analysis,” they wrote.
For both the ICU and the non-climate-controlled wards, Limaylla and colleagues reported that the inside temperature was significantly correlated with the temperature measured at a nearby meteorological station, indicating that weather conditions outside influenced indoor temperatures.
“This finding helps explain why seasonality of health care-associated infections and pathogens is found even in completely climate-controlled hospitals and wards,” Limaylla and colleagues wrote. “Our findings reinforce the importance of strengthening infection control measures during warm periods.” – by Marley Ghizzone
Disclosures: The authors report no relevant financial disclosures.