Legionella Diversity and Spatiotemporal Variation in The Occurrence of Opportunistic Pathogens within a Large Building Water System.

Helen Y Buse,Vicente Gomez-Alvarez,John S Hall,Brian J Morris,Jeffrey G Szabo

doi:10.3390/pathogens9070567

Helen Y Buse, Vicente Gomez-Alvarez + Show 3 more

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https://doi.org/10.3390/pathogens9070567

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Abstract

Understanding Legionella survival mechanisms within building water systems (BWSs) is challenging due to varying engineering, operational, and water quality characteristics unique to each system. This study aimed to evaluate Legionella, mycobacteria, and free-living amoebae occurrence within a BWS over 18–28 months at six locations differing in plumbing material and potable water age, quality, and usage. A total of 114 bulk water and 57 biofilm samples were analyzed. Legionella culturability fluctuated seasonally with most culture-positive samples being collected during the winter compared to the spring, summer, and fall months. Positive and negative correlations between Legionella and L. pneumophila occurrence and other physiochemical and microbial water quality parameters varied between location and sample types. Whole genome sequencing of 19 presumptive Legionella isolates, from four locations across three time points, identified nine isolates as L. pneumophila serogroup (sg) 1 sequence-type (ST) 1; three as L. pneumophila sg5 ST1950 and ST2037; six as L. feeleii; and one as Ochrobactrum. Results showed the presence of a diverse Legionella population with consistent and sporadic occurrence at four and two locations, respectively. Viewed collectively with similar studies, this information will enable a better understanding of the engineering, operational, and water quality parameters supporting Legionella growth within BWSs.

Highlights

Various Legionella species, such as L. anisa, L. feeleii, L. longbeachae, L. pneumophila, and L. micdadei, can cause legionellosis, which are bacterial infections resulting in either a mild flu-like illness (Pontiac Fever) or a potentially fatal form of pneumonia (Legionnaires’ Disease (LD)) [1].These infections are primarily caused by the inhalation of Legionella-contaminated aerosols generated from engineered water systems [2,3]
Contained a variety of plumbing materials, varying water flow/rates, and usage patterns at each of the sampled locations (Table 1) with previous detection of Legionella in the cold water. This building was chosen because it contains both office and production facilities where large volumes of water are used in the latter portions and smaller volumes in the office spaces for employees
No culturable Legionella was detected in samples from the polyvinyl chloride (PVC)-MA, Spigot, or Fountain location; from the second draw and biofilm samples from

Summary

Introduction

Various Legionella species, such as L. anisa, L. feeleii, L. longbeachae, L. pneumophila, and L. micdadei, can cause legionellosis, which are bacterial infections resulting in either a mild flu-like illness (Pontiac Fever) or a potentially fatal form of pneumonia (Legionnaires’ Disease (LD)) [1]. These infections are primarily caused by the inhalation of Legionella-contaminated aerosols generated from engineered water systems [2,3]. Over the past 40 years, Legionella occurrence in drinking water distribution systems (DWDSs) has been well-studied since the first speculation that exposure to aerosols, derived from contaminated water chillers, caused the deadly 1976 American Legion convention outbreak in Philadelphia [6]. Legionella occurrence has been documented in both antiquated (>100 years old) and newly constructed buildings [10,11]

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