Maša Knežević (Author), Dobrica Rončević (Author), Darija Vukić Lušić (Author), Mirna Mihelčić (Author), Rok Kogoj (Author), Darja Keše (Author), Marin Glad (Author), Arijana Cenov (Author), Mateja Ožanič (Author), Daniela Glažar Ivče (Author), Marina Šantić (Author)

Abstract

Legionellae are gram-negative bacteria most commonly found in freshwater ecosystems and purpose-built water systems. In humans, the bacterium causes Legionnaires’ disease (LD) or a Pontiac fever. In this study, the different waters (drinking water, pool water, cooling towers) in which Legionella pneumophila has been isolated were studied to assess the possible risk of bacterial spreading in the population. The influence of physical and chemical parameters, and interactions with Acanthamoeba castellanii on L. pneumophila, were analyzed by Heterotrophic Plate Count, the Colony-forming units (CFU) methods, transmission electron microscopy (TEM), and Sequence-Based Typing (SBT) analysis. During the study period (2013–2019), a total of 1932 water samples were analyzed, with the average annual rate of Legionella-positive water samples of 8.9%, showing an increasing trend. The largest proportion of Legionella-positive samples was found in cooling towers and rehabilitation centers (33.9% and 33.3%, respectively). Among the isolates, L. pneumophila SGs 2–14 was the most commonly identified strain (76%). The survival of Legionella was enhanced in the samples with higher pH values, while higher electrical conductivity, nitrate, and free residual chlorine concentration significantly reduced the survival of Legionella. Our results show that growth in amoeba does not affect the allelic profile, phenotype, and morphology of the bacterium but environmental L. pneumophila becomes more resistant to pasteurization treatment.

Keywords

Acanthamoeba;environment;infection;Legionella;

Data

Language: English
Year of publishing:
Typology: 1.01 - Original Scientific Article
Organization: UL MF - Faculty of Medicine
UDC: 616.9
COBISS: 94193155 Link will open in a new window
ISSN: 1660-4601
Views: 78
Downloads: 36
Average score: 0 (0 votes)
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Other data

Secondary language: Slovenian
Secondary keywords: Acanthamoeba;okolje;okužba;Legionela;
Type (COBISS): Article
Pages: str. 1-19
Volume: ǂVol. ǂ19
Issue: ǂiss. ǂ3
Chronology: 2022
DOI: 10.3390/ijerph19031099
ID: 15504112