Distribution ofLegionellaSpecies from Environmental Water Sources of Public Facilities and Genetic Diversity ofL. pneumophilaSerogroup 1 in South Korea

Abstract

A total of 560 Legionella species were isolated from environmental water sources from public facilities from June to September 2008 throughout South Korea. The distribution of Legionella isolates was investigated according to geographical region, facility type, and sample type. The genetic diversity of 104 isolates of Legionella pneumophila serogroup 1 (sg 1) was analyzed by sequence-based typing (SBT). L. pneumophila was distributed broadly throughout Korea, accounting for 85.0% of the isolates, and L. pneumophila sg 1 predominated in all of the public facilities except for the springs. Legionella anisa and Legionella bozemanii predominated among non-L. pneumophila species (48.1% and 21.0%, respectively). The second most dominant strain differed depending on the facility type: L. anisa was the second most dominant strain in the buildings (10.8%), L. pneumophila sg 5 in public baths (21.6%), L. pneumophila sg 6 in factories (12.0%), and L. pneumophila sg 7 in hospitals (13.1%). In the SBT analysis, 104 L. pneumophila sg 1 isolates were differentiated into 26 sequence types (STs) and categorized into 3 clonal groups (CGs) and 10 singleton STs via the eBURST V3 program. ST1, a potential founder of major CG1, was commonly distributed (48.1%). The dominant ST in hot water was ST-K1 (7, 12, 17, 3, 35, 11, 11), which was designated in this study (36.1%). The second most dominant strain differed depending on the type of facility from which the samples were obtained. The unique allelic profile of ST-K1, obtained from hot water, was not found in the European Working Group for Legionella Infections (EWGLI) SBT database.

Prevalence of Sequence Types among Clinical and Environmental Isolates of Legionella pneumophila Serogroup 1 in the United States from 1982 to 2012

“…In South Korea, ST1 was the predominant ST in isolates from cooling towers, whereas ST-K1, unique to South Korea, was the dominant ST in hot water samples (29). In Japan, ST1 was more prevalent in cooling tower water (74%) than in bathwater (12%) and was not isolated from any soil samples (28).…”

“…According to the studies of the distribution of Lp1 STs in different regions of the world, it appears that the most prevalent ST among clinical and environmental populations of Lp1 is either ST1 (8,(27)(28)(29)(30)(31)(32) or an ST that is confined to a specific geographic region (33)(34)(35). For example, in Belgium and the United Kingdom, the most frequently detected ST among clinical isolates was ST47 (9,35).…”

Insertion Sequences as Highly Resolutive Genomic Markers for Sequence Type 1 Legionella pneumophila Paris

“…A consensus trend emerged, with all data revealing both a high level of genetic diversity in Legionella and the emergence of specific groups of clones that showed high similarities and were responsible for both sporadic legionellosis cases and worldwide outbreaks (1,4,26,34,35,37,49,58). In particular, isolates from ST1 (which includes the widely distributed Paris strain), ST47, and ST222 have been detected in sporadic and outbreak cases.…”

“…Several studies combined these different methodologies to infer the distribution of Legionella isolates, especially from L. pneumophila serogroup 1, using collections of isolates sampled all over the world-in Japan (1), Canada (49,58), the United States (35), South Korea (37), and Europe (22,23,26). A consensus trend emerged, with all data revealing both a high level of genetic diversity in Legionella and the emergence of specific groups of clones that showed high similarities and were responsible for both sporadic legionellosis cases and worldwide outbreaks (1,4,26,34,35,37,49,58).…”

Applicability assessment of ceramic microbeads coated with hydroxyapatite-binding silver/titanium dioxide ceramic composite earthplus™ to the eradication of Legionella in rainwater storage tanks for household use

“…20,21 The water systems of artificial facilities, including potable water systems, 22,23 spa water, 24 and cooling towers 25,26 in large buildings, hotels, hospitals, and public baths that are contaminated with Legionella are the implicated sources of outbreaks and sporadic cases of Legionnaires' disease. Thus, it is important, from a public health perspective, not only to continually survey environmental water systems for the presence of Legionella [27][28][29][30] but also to make microbiological control of Legionella organisms in water environments. In particular, legionellosis occurs frequently in health care settings due to patients' susceptibility and complexity of hospital water distribution systems.…”