Surveillance, prevention, and control of legionellosis in a tropical city-state

Goh, Kee Tai; Ng, D. L. K.; Yap, Jennifer; Ma, Stefan; Ooi, Eng Eong

doi:10.1016/j.ajic.2004.12.001

Cited by 14 publications

(11 citation statements)

References 9 publications

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“…In another study conducted during 1998–2002, Legionella spp. bacteria were found in 16.2% of mist fans and 23.7% of water taps and shower heads ( 35 ). However, these bacteria were not detected in the municipal potable water system because the surveillance program of the Public Utilities Board (National Water Agency) started in 2003.…”

Section: Discussionmentioning

confidence: 99%

Epidemiology and Control of Legionellosis, Singapore

Lam¹

2011

Emerg. Infect. Dis.

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To determine trends and clinical and epidemiologic features of legionellosis in Singapore, we studied cases reported during 2000–2009. During this period, 238 indigenous and 33 imported cases of legionellosis were reported. Cases were reported individually and sporadically throughout each year. Although the annual incidence of indigenous cases had decreased from 0.46 cases per 100,000 population in 2003 to 0.16 cases per 100,000 in 2009, the proportion of imported cases increased correspondingly from 6.2% during 2000–2004 to 27.3% during 2005–2009 (p<0.0005). The prevalence of Legionella bacteria in cooling towers and water fountains was stable (range 12.1%–15.3%) during 2004–August 2008.

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Section: Discussionmentioning

confidence: 99%

Epidemiology and Control of Legionellosis, Singapore

Lam¹

2011

Emerg. Infect. Dis.

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confidence: 99%

“…(9, 21), Balamuthia mandrillaris (54), and Naegleria fowleri (59), can proliferate in drinking water-related biofilms at elevated temperatures (36). In addition, Legionella pneumophila, the main etiologic agent of Legionnaires' disease (12), which proliferates in freshwater at temperatures above 25°C (57), is frequently observed in these environments (14,31,39).FLP in aquatic environments feed on bacteria, fungi, other protozoa, and organic detritus in biofilms and sediments or in the planktonic phase (32). The abundance of prey organisms and detritus depends on the water composition and the hydraulic conditions in distribution systems, which therefore also affect both the FLP abundance and community composition (52, 55).…”

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confidence: 99%

Relationships between Free-Living Protozoa, Cultivable Legionella spp., and Water Quality Characteristics in Three Drinking Water Supplies in the Caribbean

Valster

Wullings

Berg

et al. 2011

Appl Environ Microbiol

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The study whose results are presented here aimed at identifying free-living protozoa (FLP) and conditions favoring the growth of these organisms and cultivable Legionella spp. in drinking water supplies in a tropical region. Treated and distributed water (؎30°C) of the water supplies of three Caribbean islands were sampled and investigated with molecular techniques, based on the 18S rRNA gene. The protozoan host Hartmannella vermiformis and cultivable Legionella pneumophila were observed in all three supplies. Operational taxonomic units (OTUs) with the highest similarity to the potential or candidate hosts Acanthamoeba spp., Echinamoeba exundans, E. thermarum, and an Neoparamoeba sp. were detected as well. In total, 59 OTUs of FLP were identified. The estimated protozoan richness did not differ significantly between the three supplies. In supply CA-1, the concentration of H. vermiformis correlated with the concentration of Legionella spp. and clones related to Amoebozoa predominated (82%) in the protozoan community. These observations, the low turbidity In tropical regions, the water temperature in drinking water distribution system is permanently about 30°C (4). In these regions, free-living protozoa (FLP), serving as hosts for pathogenic bacteria, including Acanthamoeba spp. (1, 38), Hartmannella spp. (37), and Naegleria spp. (38, 49), have been observed in surface water, wastewater, cooling towers, and drinking water (3,5,19,45). Certain FLP with pathogenic properties, viz. Acanthamoeba spp. (9, 21), Balamuthia mandrillaris (54), and Naegleria fowleri (59), can proliferate in drinking water-related biofilms at elevated temperatures (36). In addition, Legionella pneumophila, the main etiologic agent of Legionnaires' disease (12), which proliferates in freshwater at temperatures above 25°C (57), is frequently observed in these environments (14,31,39).FLP in aquatic environments feed on bacteria, fungi, other protozoa, and organic detritus in biofilms and sediments or in the planktonic phase (32). The abundance of prey organisms and detritus depends on the water composition and the hydraulic conditions in distribution systems, which therefore also affect both the FLP abundance and community composition (52, 55). Most information on community composition and abundance of FLP in freshwater environments has been obtained by using cultivation methods and microscopy. Recently, however, the presence and identities of such organisms in drinking water supplies in temperate regions have been studied by using molecular methods for detection and identification (33, 51). In two groundwater supplies in the Netherlands a total of 127 operational taxonomic units (OTUs) of FLP were identified based on their 18S rRNA gene sequences. FLP, mostly pathogens, have been characterized in only a few studies in tropical regions (3,5,19). In recent reviews it was concluded that more research is needed to determine which factors favor the growth of these organisms in water supplies (47,48).Cases of Legionnaires' disease have been reporte...

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“…PCR technique can resolve the mentioned obstacles and increase the detection accuracy. 37,38 The selection of specific target regions of the L. pneumophila gene is important to reach precise results. To this end, we elected mip gene that covered all serogroups as specified by blasting of genetic databases.…”

Section: Discussionmentioning

confidence: 99%

Prevalence and molecular distribution of Legionella pneumophila in cold water taps across Alborz province, Iran

Yaslianifard

Mohammadzadeh

Pourmand

et al. 2019

Clinical Epidemiology and Global Health

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Background: The aim of this study is to explore the distribution of Legionella pneumophila (serogroups 1-6) in cold water taps across Alborz province, Karaj, Iran. In addition, some other non-fastidious gram-negative bacteria not belonging to the Enterobacteriaceae family (GNB-NE) were followed. Subject: A total of 162 water samples were collected from 6 countries and tested by culture and genus-specific polymerase chain reaction (PCR). The L. pneumophila isolates were subsequently analyzed by monoclonal antibodies (MAbs) for serogroup identification, molecularly by PCR, and sequencing for genetic diversity. The patterns of resistance to antibiotics were determined by disk diffusion. Results: Fifteen (9.25%) samples were detected as positive for L. pneumophila by PCR and 12 (7.4%) samples yielded growth in culture. All isolates of L. pneumophila were belonged to serogroup 1. Fifteen GNB-NE species were isolated from the samples, including nine isolates of Pseudomonas aeruginosa and six isolates of Acinetobacter spp. Antibiotic resistance was detected in 3 isolates of P. aeruginosa. Conclusions: Despite the prevalence of L. pneumophila, few clinical cases have been reported, which may be due to underdiagnosis of the disease caused by it. Therefore, the prompt attention should be paid to do clinical diagnosis of legionellosis by the effective diagnostic tests from patients with compatible clinical symptoms.

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Surveillance, prevention, and control of legionellosis in a tropical city-state

Cited by 14 publications

References 9 publications

Epidemiology and Control of Legionellosis, Singapore

Epidemiology and Control of Legionellosis, Singapore

Relationships between Free-Living Protozoa, Cultivable Legionella spp., and Water Quality Characteristics in Three Drinking Water Supplies in the Caribbean

Prevalence and molecular distribution of Legionella pneumophila in cold water taps across Alborz province, Iran

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