Patrizia De Filippis1, Cinzia Mozzetti2, Alessandra Messina3, Gian Loreto D'Alò4. 1. Section of Hygiene, Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Via Montpellier 1, 00133 Rome, Italy. Electronic address: patrizia.de.filippis@uniroma2.it. 2. Section of Hygiene, Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Via Montpellier 1, 00133 Rome, Italy. Electronic address: cinzia.mozzetti@uniroma2.it. 3. Section of Hygiene, Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Via Montpellier 1, 00133 Rome, Italy. Electronic address: alessandra.messina@uniroma2.it. 4. Section of Hygiene, Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Via Montpellier 1, 00133 Rome, Italy. Electronic address: gianloretod@gmail.com.
Abstract
BACKGROUND: Although historically the focus has been placed above all on hospital infections and travel-associated outbreaks, most of the cases of Legionella infection are sporadic and occur in community-dwellers. OBJECTIVES: To evaluate the presence and load of Legionella in hot water systems of non-healthcare facilities that host closed communities. Furthermore, we tried to verify the association between Heterotrophic Plate Counts (HPCs) and presence of Legionella. METHODS: We collected hot water and biofilm samples from the showerheads of retirement homes and group homes. Samples were tested by culture method for the presence of Legionella. Confirmation and identification were carried out through Latex test and PCR. We determined the HPCs at 22 and 37 °C by the pour plate method. Statistics performed through STATA. RESULTS: We collected 140 hot water and biofilm samples, 95 from 26 retirement homes and 35 from 9 group homes. Legionella was found in 36.8% samples collected from retirement homes and only in 10.3% group homes' samples (p = 0.01). Legionella was identified more frequently in water than in biofilm (29.8% vs 16.9%); just in one case the pathogen was found in the biofilm only. L. pneumophila sg 1 was the pathogen more frequently isolated (65.8%), with an average load of 2720 CFU/L (SD = 8393 CFU/L). We have often noticed a high microbial contamination (67% of HPCs >200 CFU/mL) and identified a higher prevalence of Legionella for intermediate values of HPC 22 °C (p = 0.011). 32% of people hosted in retirement homes were exposed to Legionella. CONCLUSIONS: Colonization of water-systems of retirement homes and group homes is anything but occasional, and in our survey it mainly affects the former, moreover often due to L. pneumophila sg 1. The search for the pathogen in the biofilm has proved to be of little use. The relationship between HPC and Legionella deserves further studies.
BACKGROUND: Although historically the focus has been placed above all on hospital infections and travel-associated outbreaks, most of the cases of Legionella infection are sporadic and occur in community-dwellers. OBJECTIVES: To evaluate the presence and load of Legionella in hot water systems of non-healthcare facilities that host closed communities. Furthermore, we tried to verify the association between Heterotrophic Plate Counts (HPCs) and presence of Legionella. METHODS: We collected hot water and biofilm samples from the showerheads of retirement homes and group homes. Samples were tested by culture method for the presence of Legionella. Confirmation and identification were carried out through Latex test and PCR. We determined the HPCs at 22 and 37 °C by the pour plate method. Statistics performed through STATA. RESULTS: We collected 140 hot water and biofilm samples, 95 from 26 retirement homes and 35 from 9 group homes. Legionella was found in 36.8% samples collected from retirement homes and only in 10.3% group homes' samples (p = 0.01). Legionella was identified more frequently in water than in biofilm (29.8% vs 16.9%); just in one case the pathogen was found in the biofilm only. L. pneumophila sg 1 was the pathogen more frequently isolated (65.8%), with an average load of 2720 CFU/L (SD = 8393 CFU/L). We have often noticed a high microbial contamination (67% of HPCs >200 CFU/mL) and identified a higher prevalence of Legionella for intermediate values of HPC 22 °C (p = 0.011). 32% of people hosted in retirement homes were exposed to Legionella. CONCLUSIONS: Colonization of water-systems of retirement homes and group homes is anything but occasional, and in our survey it mainly affects the former, moreover often due to L. pneumophila sg 1. The search for the pathogen in the biofilm has proved to be of little use. The relationship between HPC and Legionella deserves further studies.
Authors: Ileana Federigi; Osvalda De Giglio; Giusy Diella; Francesco Triggiano; Francesca Apollonio; Marilena D'Ambrosio; Lorenzo Cioni; Marco Verani; Maria Teresa Montagna; Annalaura Carducci Journal: Int J Environ Res Public Health Date: 2022-02-10 Impact factor: 3.390
Authors: Michele Totaro; Anna Laura Costa; Lorenzo Frendo; Sara Profeti; Beatrice Casini; Antonio Gallo; Gaetano Privitera; Angelo Baggiani Journal: Int J Environ Res Public Health Date: 2020-09-26 Impact factor: 3.390