Articles producció científica> Ciències Mèdiques Bàsiques

Heterotrophic Plate Count Can Predict the Presence of Legionella spp. in Cooling Towers

  • Identification data

    Identifier: imarina:9295204
    Authors:
    Sanchis MInza IFigueras MJ
    Abstract:
    Legionella pneumophila (Lp) colonizes aquatic environments and is a potential pathogen to humans, causing outbreaks of Legionnaire’s disease. It is mainly associated with contaminated cooling towers (CTs). Several regulations, including Spanish legislation (Sl), have introduced the analysis of heterotrophic plate count (HPC) bacteria and Legionella spp. (Lsp) in management plans to prevent and control Legionella outbreaks from CTs. The 2003 Sl for CTs (RD 865/2003) considered that concentrations of HPC bacteria ≤10,000 cfu/mL and of Lsp ≤100 cfu/L are safe; therefore, no action is required, whereas management actions should be implemented above these standards. We have investigated to what extent the proposed standard for HPC bacteria is useful to predict the presence of Lsp in cooling waters. For this, we analyzed Lsp and HPC concentrations, water temperature, and the levels of chlorine in 1376 water samples from 17 CTs. The results showed that in the 1138 water samples negative for Legionella spp. (LN), the HPC geometric mean was significantly lower (83 cfu/mL, p < 0.05) than in the positive Lsp. samples (135 cfu/mL). Of the 238 (17.3%) LP samples, 88.4% (210/238) were associated with values of HPC ≤10,000 cfu/mL and most of them showed HPC concentrations ≤100 (53.7%). In addition, a relatively low percentage of LP (28/238, 11.6%) samples were associated with HPC bacteria concentrations >10,000 cfu/mL, indicating that this standard does not predict the colonization risk for Legionella in the CTs studied. The present study has demonstrated that a threshold concentration ≤100 cfu/mL of HPC bacteria could better predict the higher concentration of Legionella in CTs, which will aid in preventing possible outbreaks.
  • Others:

    Author, as appears in the article.: Sanchis M; Inza I; Figueras MJ
    Department: Ciències Mèdiques Bàsiques
    URV's Author/s: Figueras Salvat, María Josefa / Sanchis Talón, Marta
    Keywords: Legionella spp. (lsp) Heterotrophic plate count (hpc) Cooling towers (cts)
    Abstract: Legionella pneumophila (Lp) colonizes aquatic environments and is a potential pathogen to humans, causing outbreaks of Legionnaire’s disease. It is mainly associated with contaminated cooling towers (CTs). Several regulations, including Spanish legislation (Sl), have introduced the analysis of heterotrophic plate count (HPC) bacteria and Legionella spp. (Lsp) in management plans to prevent and control Legionella outbreaks from CTs. The 2003 Sl for CTs (RD 865/2003) considered that concentrations of HPC bacteria ≤10,000 cfu/mL and of Lsp ≤100 cfu/L are safe; therefore, no action is required, whereas management actions should be implemented above these standards. We have investigated to what extent the proposed standard for HPC bacteria is useful to predict the presence of Lsp in cooling waters. For this, we analyzed Lsp and HPC concentrations, water temperature, and the levels of chlorine in 1376 water samples from 17 CTs. The results showed that in the 1138 water samples negative for Legionella spp. (LN), the HPC geometric mean was significantly lower (83 cfu/mL, p < 0.05) than in the positive Lsp. samples (135 cfu/mL). Of the 238 (17.3%) LP samples, 88.4% (210/238) were associated with values of HPC ≤10,000 cfu/mL and most of them showed HPC concentrations ≤100 (53.7%). In addition, a relatively low percentage of LP (28/238, 11.6%) samples were associated with HPC bacteria concentrations >10,000 cfu/mL, indicating that this standard does not predict the colonization risk for Legionella in the CTs studied. The present study has demonstrated that a threshold concentration ≤100 cfu/mL of HPC bacteria could better predict the higher concentration of Legionella in CTs, which will aid in preventing possible outbreaks.
    Thematic Areas: Molecular biology Microbiology (medical) Microbiology Infectious diseases Immunology and microbiology (miscellaneous) Immunology and microbiology (all) Immunology and allergy General immunology and microbiology Farmacia
    licence for use: https://creativecommons.org/licenses/by/3.0/es/
    Author's mail: marta.sanchis@urv.cat mariajose.figueras@urv.cat
    Author identifier: 0000-0001-7251-6792 0000-0002-2268-8980
    Record's date: 2024-08-03
    Papper version: info:eu-repo/semantics/publishedVersion
    Link to the original source: https://www.mdpi.com/2076-0817/12/3/466
    Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
    Papper original source: Pathogens. 12 (3):
    APA: Sanchis M; Inza I; Figueras MJ (2023). Heterotrophic Plate Count Can Predict the Presence of Legionella spp. in Cooling Towers. Pathogens, 12(3), -. DOI: 10.3390/pathogens12030466
    Article's DOI: 10.3390/pathogens12030466
    Entity: Universitat Rovira i Virgili
    Journal publication year: 2023
    Publication Type: Journal Publications
  • Keywords:

    Immunology and Allergy,Immunology and Microbiology (Miscellaneous),Infectious Diseases,Microbiology,Microbiology (Medical),Molecular Biology
    Legionella spp. (lsp)
    Heterotrophic plate count (hpc)
    Cooling towers (cts)
    Molecular biology
    Microbiology (medical)
    Microbiology
    Infectious diseases
    Immunology and microbiology (miscellaneous)
    Immunology and microbiology (all)
    Immunology and allergy
    General immunology and microbiology
    Farmacia
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