Hot water plumbing in residences and office buildings have distinctive risk of Legionella pneumophila contamination

Donohue, Maura J.; Mistry, Jatin H.; Tucker, Nicole; Vesper, Stephen

doi:10.1016/j.ijheh.2022.114023

Cited by 4 publications

(4 citation statements)

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“…They reported that the highest frequency of L. pneumophila ‐positive samples was in November (21.6%), followed by April (21%) and August (19.1%). Likewise, Donohue et al (2022) reported that L. pneumophila 's highest frequencies in the samples were detected in March–August for the office buildings and in June–November for the residences. Sharaby et al (2019) stated that the incidence of L. pneumophila is highest in summer and autumn, while Abdalla et al (2020) claimed to be in spring and autumn.…”

Section: Resultsmentioning

confidence: 85%

“…More than 20 subspecies of Legionella spp. can cause human infections (Donohue et al, 2022; Li et al, 2015). Two basic mechanisms have been proposed for aquatic L. pneumophila to reach the lungs: (1) the bacteria settles in the upper respiratory system and reaches the lungs by aspiration, or (2) the water droplets (aerosols) hanging in the air cause this bacteria to reach the lungs through respiration (Moumanis et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Long‐term monitoring of the microbial quality and Legionnaires' disease risk in tap water from mass catering establishments

2023

Water & Environment J

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Legionnaires' disease is caused by Legionella (L.) pneumophila. Inhaling aerosolized water containing this bacteria is the most common transmission route. Shower heads used in the catering industry's dishwashing units are also potential amplifying systems for bacteria and possible sources of infection by generating droplets and aerosols. Therefore, these systems should not contain pathogenic bacteria. This study aims to monitor the microbial quality, Legionnaires' disease risk and L. pneumophila presence in tap water samples from the water outlet of the shower‐type dishwashing unit of mass catering establishments for a year. Seventy‐two tap water samples were microbiologically tested for total mesophilic aerobic bacteria count, coliform, Escherichia (E.) coli and L. pneumophila. DNA was isolated from L. pneumophila‐positive samples, and their serogroup was characterized by real‐time PCR. The correlation between seasonal variation and prevalence of L. pneumophila serogroup and L. pneumophila and other indicator bacteria were statistically tested by Spearman rank test (p < 0.05). Findings showed that 17 (24%) samples had microbial growth, 14 (19.4%) were positive for L. pneumophila and 13 isolates were characterized as L. pneumophila serogroup 1. The statistical analysis showed no significant correlation between seasonal variation (p = 0.491) and L. pneumophila and total mesophilic aerobic bacteria count, coliform and E. coli (p = 0.923). Overall, Legionella spp. is an essential indicator of the microbial quality in the tap water from mass catering establishments and should be regularly monitored for public health independently from seasonal variation and other indicator bacteria.

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Section: Resultsmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Long‐term monitoring of the microbial quality and Legionnaires' disease risk in tap water from mass catering establishments

2023

Water & Environment J

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“…14 Ideal L. pneumophila growth conditions are found in plumbing allowing amplification even when not detected in influent water, 15 or when disinfectant is present. 16,17 Stagnation may provide particularly ideal conditions, with disinfectant decay, nutrient availability, and warm water temperatures. A study analyzing water quality in student dormitories discovered that the microbial community composition changed and cell counts increased by a factor of 10 000 cells per mL following six days of stagnation.…”

Section: Introductionmentioning

confidence: 99%

Water quality during extended stagnation and flushing in a college residential hall

Angert,

Ley,

et al. 2023

Environ. Sci.: Water Res. Technol.

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“…More than 67 % of the study participants live in buildings built between 1950's and 1990's and the plumbing systems had not been renovated in the majority of cases. However, previous research has confirmed equal probability of Legionella contamination in old and new buildings, while direct disinfection measures can improve public health (Donohue et al, 2022).…”

Section: The Main Reservoirs Formentioning

confidence: 95%

Prevalence, Genetic Diversity, and Virulence Potential of Legionella spp. Summary of the Doctoral Thesis

Valciņa

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Legionella spp. is one of the most important water-borne pathogens that can cause both outbreaks and sporadic cases. Legionella is spread by water aerosols containing the bacteria. In the form of aerosols, bacteria can spread several kilometres from the primary source of infection while remaining viable. Legionellosis is a preventable disease and a form of atypical pneumonia caused by Legionella pneumophila and related bacteria. Clinical manifestations of the disease range from a mild, self-limiting flu-like illness (Pontiac fever) to potentially fatal pneumonia (Legionnaires' disease). The aim of the study was to investigate Legionella spp. distribution trends, genetic diversity and virulence potential for diagnosis and prevention of legionellosis in Latvia. Materials and methods. To assess the seroprevalence of L. pneumophila in the general healthy population and to identify associated risk factors, 2007 blood samples were collected from healthy blood donors. To evaluate Legionella spp. distribution in water supply systems, 1467water samples were taken in different types of buildings. 137 L. pneumophila isolates were selected for the study of genetic diversity and virulence genes were determined for 58 isolates. Immunoenzymatic reaction was performed for all blood samples to detect IgG antibodies against L. pneumophila SG 1-6. Determination of Legionella spp. in water and biofilm samples was performed according to a standardized method. Free-living protozoa were determined morphologically and by three different PCR protocols. Whole genome sequencing of L. pneumophila isolates was performed with Illumina MiSeq. Sequence-based typing was performed according to the scheme developed by ESCMID. cgMLST typing was performed using the previously described protocol. The database of virulence factors was used to determine virulence determinants. Results. The seroprevalence of L. pneumophila SG 1-6 in blood donors was 4.8 % and 0.2 % of donors were seropositive for L. pneumophila SG1. Seroprevalence was higher in women (5.9 %) than men (3.3 %), and in regions with a larger population, ranging from 3.5 % in rural regions to 6.8 % in the capital Riga. Legionella spp. prevalence in water supply systems varied from an average of 25 % in cold water samples to 35 % in hot water samples. The predominant L. pneumophila serogroup (SG) was SG 3, which was identified in 208 of 482 cases (43.2 %). At least one free-living amoeba genus was detected in at least 77.2 % of the samples. The average hot water temperature was 47.8 ± 0.7 °C. Temperature measurements showed that only 249 out of 1275 hot water samples exceeded 55 °C. Overall, 137 L. pneumophila strains included in the study represented 46 sequence types, including new 10 sequence types, previously unrecorded in the world. Using cgMLST typing 116 genotypes were obtained. 420 virulence genes were identified of which 260 genes were found in all sequenced L. pneumophila isolates. Virulence factors encoding enhC, htpB, omp28 and mip genes were detected in all isolates, suggesting that adhesion, attachment and entry into the host cell are enabled for all isolates. Relative frequency of virulence genes among L. pneumophila isolates was high. Conclusions. Residents of apartment buildings are exposed to a higher risk of legionellosis than those living in private houses (OR = 2.23; p = 0.011). The highest risk of seropositivity was for residents of buildings with centralized hot water supply (OR = 3.16; p = 0.001). High Legionella spp. prevalence in water supply systems is related to low hot water temperature (average 47.8 ± 0.7 °C) and high presence of free-living amoebae (84.2 %). Environmental isolates of L. pneumophila exhibited a high diversity of SBT and cgMLST sequence types and showed signs of regional clonal expansion, with ST-338, ST-366 and ST-1104 as the predominant sequence type group characteristic of our region. The relative frequency of virulence genes suggests that L. pneumophila isolates have a high virulence potential and the presence of a wide range of virulence factors. 3.1 Basic medicine; Sub-Sector – Other Basic Medicines. Keywords: Legionella, genetic diversity, cgMLST typing, virulence.

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Hot water plumbing in residences and office buildings have distinctive risk of Legionella pneumophila contamination

Cited by 4 publications

References 37 publications

Long‐term monitoring of the microbial quality and Legionnaires' disease risk in tap water from mass catering establishments

Long‐term monitoring of the microbial quality and Legionnaires' disease risk in tap water from mass catering establishments

Water quality during extended stagnation and flushing in a college residential hall

Prevalence, Genetic Diversity, and Virulence Potential of Legionella spp. Summary of the Doctoral Thesis

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