Application of Hydrogen Peroxide as an Innovative Method of Treatment for Legionella Control in a Hospital Water Network.

Beatrice Casini,Anna Costa,Francesco Aquino,Benedetta Tuvo,Michele Totaro,Gaetano Privitera,Mario Miccoli,Irio Galli,Angelo Baggiani,Paola Valentini,Carlo Giustarini,Laura Manfredini

doi:10.3390/pathogens6020015

Beatrice Casini, Anna Costa + Show 10 more

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https://doi.org/10.3390/pathogens6020015

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Journal: Pathogens	Publication Date: Apr 17, 2017
Citations: 26	License type: CC BY 4.0

Affiliation: University of Pisa, Ospedale di Livorno

Abstract

Objectives: To evaluate the effectiveness of hydrogen peroxide (HP) use as a disinfectant in the hospital water network for the control of Legionella spp. colonization. Methods: Following the detection of high levels of Legionella contamination in a 136-bed general hospital water network, an HP treatment of the hot water supply (25 mg/L) was adopted. During a period of 34 months, the effectiveness of HP on Legionella colonization was assessed. Legionella was isolated in accordance with ISO-11731 and identification was carried out by sequencing of the mip gene. Results: Before HP treatment, L. pneumophila sg 2–15 was isolated in all sites with a mean count of 9950 ± 8279 cfu/L. After one-month of HP treatment, we observed the disappearance of L. pneumophila 2–15, however other Legionella species previously not seen were found; Legionella pneumophila 1 was isolated in one out of four sampling sites (2000 cfu/L) and other non-pneumophila species were present in all sites (mean load 3000 ± 2887 cfu/L). Starting from September 2013, HP treatment was modified by adding food-grade polyphosphates, and in the following months, we observed a progressive reduction of the mean load of all species (p < 0.05), resulting in substantial disappearance of Legionella colonization. Conclusion: Hydrogen peroxide demonstrated good efficacy in controlling Legionella. Although in the initial phases of treatment it appeared unable to eliminate all Legionella species, by maintaining HP levels at 25 mg/L and adding food-grade polyphosphates, a progressive and complete control of colonization was obtained.

Highlights

Legionella spp. is a Gram-negative aerobic opportunistic bacterium, responsible for a severe form of pneumonia called Legionnaires’ disease (LD) [1]
The bacterial species was identified as Legionella pneumophila 2–15
This potentially critical situation led to the application of a hydrogen peroxide (HP)-based disinfection strategy on

Summary

Introduction

Legionella spp. is a Gram-negative aerobic opportunistic bacterium, responsible for a severe form of pneumonia called Legionnaires’ disease (LD) [1]. It is a waterborne human pathogen frequently associated with nosocomial infections, among immunosuppressed patients such as those with acquired immune-deficiency syndrome (AIDS), transplant patients, and those undergoing aggressive chemotherapy [2]. The case fatality rate of LD associated with outbreaks is lower than that of sporadic cases, generally around 8–15%, but it can be higher, especially in the case of hospital-acquired infections, AIDS patients, transplant patients, and those undergoing aggressive chemotherapy [3]. The genus Legionella includes 57 species (including subspecies) and about 70 serogroups, not all associated with human disease. The species most frequently detected in diagnosed cases [5] is Legionella pneumophila, consisting of 16 serogroups; Legionella pheumophila serogroup 1, responsible for the first identified outbreak, occurred in 1976 in Philadelphia (USA), is the cause of 95% of infections in Europe and 85% in the world [6]

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