Factors Associated with Detection in the Water Systems of National Lodging Organization Facilities with Water Management Programs in the United States.

A better understanding of risk factors and the predictive capability of water management program (WMP) data in detecting are needed to inform the efforts aimed at reducing growth and preventing outbreaks of Legionnaires' disease. Using WMPs and testing data from a national lodging organization in the United States, we aimed to (1) identify factors associated with detection and (2) assess the ability of WMP disinfectant and temperature metrics to predict detection. We conducted a logistic regression analysis to identify WMP metrics associated with serogroup 1 (SG1) detection. We also estimated the predictive values for each of the WMP metrics and SG1 detection. Of 5435 testing observations from 2018 to 2020, 411 (7.6%) had SG1 detection, and 1606 (29.5%) had either SG1 or non-SG1 detection. We found failures in commonly collected WMP metrics, particularly at the primary test point for total disinfectant levels in hot water, to be associated with SG1 detection. These findings highlight that establishing and regularly monitoring water quality parameters for WMPs may be important for preventing growth and subsequent disease. However, while unsuitable water quality parameter results are associated with detection, this study found that they had poor predictive value, due in part to the low prevalence of SG1 detection in this dataset. These findings suggest that testing provides critical information to validate if a WMP is working, which cannot be obtained through water quality parameter measurements alone.