Control of legionellae in a new healthcare facility following implementation of a thermal control strategy

Abstract

Introduction: The management of the Legionella risk in hospitals is essentially related to preventive measures of the hot-water supplies.

Aim: To monitor the control of legionellae before and after moving to a new hospital facility.

Methods: We implemented a survey program based on the surveillance of the temperature of the hot-water supply and detection and counting of Legionella pneumophila and Legionella spp. by quantitative polymerase chain reaction and culture methods.

Results: Our survey program revealed that the hot-water system was colonized by L. pneumophila and Legionella spp. before the arrival of the first patients, despite the implementation of preventive measures. Thus, maintenance on the hot-water production system and subsequent cleaning and superheat disinfection of the hot-water supplies were performed, leading to the eradication of L. pneumophila reservoirs and the decrease of Legionella spp. reservoirs. No reservoirs of L. pneumophila and only rare persistent reservoirs of Legionella spp. were detected after the transfer of hospitalized patients to the new healthcare facility and during the following four years, demonstrating the effectiveness of our corrective measures, without using biocides. L. anisa was identified as the only strain of viable and cultivable Legionella spp. and was undetected during the last year.

Conclusions: The strict application of our survey program before and after moving to the new hospital associated with strict implementation of corrective measures allowed us to efficiently manage the Legionella-linked risk during this period.

Keywords:

• Legionella pneumophila
• Legionella anisa
• Microbiological survey program
• Thermal control strategy

Disclosure statement

No potential conflict of interest was reported by the authors.

Table 2. Results of the Legionella anisa counts by bacterial culture and Legionella spp. counts by qPCR in the domestic water system supplies after moving to the new building.