Legionella species are abundant in the built environment and are increasingly recognized as a cause of Legionnaires' disease (LD). As the number of cases of Legionnaires' disease acquired by local communities in the Seoul metropolitan area in Korea has been increased, there was concern that changes in environmental factors could affect disease outbreaks. We described the association between climatic variables and occurrence of legionellosis in Korea and Legionella detection rate in Seoul area. A total of 418 cases of legionellosis were reported between 2014 and 2017. There was a seasonal peak in summer. LD continuously occurred from early spring to winter every year and rapidly increased in summer. In the regression analysis, the primary variables of interest- PM2.5 (µg/m³), NO₂ (ppb), and a number of the date of issue O₃ warning were not significant except for average temperature (R²=0.8075). The Legionella detection rate in Seoul, Korea showed a trend similar to precipitation (P=0.708, ANOVA). A relatively high proportion of Legionella detection rate was shown, especially cooling tower (17.7%) and public bath (19.3%). This finding is in line with current understanding of the ecological profile of this pathogen and supports the assertion that legionellosis occurs through contamination of water sources.
Baths ; Disease Outbreaks ; Epidemiology ; Korea ; Legionella ; Legionellosis ; Legionnaires' Disease ; Regression Analysis ; Seasons ; Seoul ; Water

The harshness of legionellosis differs from mild Pontiac fever to potentially fatal Legionnaire's disease. The increasing development of drug resistance against legionellosis has led to explore new novel drug targets. It has been found that phosphoglucosamine mutase, phosphomannomutase, and phosphoglyceromutase enzymes can be used as the most probable therapeutic drug targets through extensive data mining. Phosphoglucosamine mutase is involved in amino sugar and nucleotide sugar metabolism. The purpose of this study was to predict the potential target of that specific drug. For this, the 3D structure of phosphoglucosamine mutase of Legionella pneumophila (strain Paris) was determined by means of homology modeling through Phyre2 and refined by ModRefiner. Then, the designed model was evaluated with a structure validation program, for instance, PROCHECK, ERRAT, Verify3D, and QMEAN, for further structural analysis. Secondary structural features were determined through self-optimized prediction method with alignment (SOPMA) and interacting networks by STRING. Consequently, we performed molecular docking studies. The analytical result of PROCHECK showed that 95.0% of the residues are in the most favored region, 4.50% are in the additional allowed region and 0.50% are in the generously allowed region of the Ramachandran plot. Verify3D graph value indicates a score of 0.71 and 89.791, 1.11 for ERRAT and QMEAN respectively. Arg419, Thr414, Ser412, and Thr9 were found to dock the substrate for the most favorable binding of S-mercaptocysteine. However, these findings from this current study will pave the way for further extensive investigation of this enzyme in wet lab experiments and in that way assist drug design against legionellosis.
Computer Simulation* ; Data Mining ; Drug Delivery Systems ; Drug Design ; Drug Resistance ; Fever ; Legionella pneumophila* ; Legionellosis* ; Legionnaires' Disease ; Metabolism ; Phosphoglycerate Mutase

BACKGROUND: Because of the ubiquity of Legionella species in aquatic environments, molecular epidemiological analysis of Legionella isolates is important in investigation for source of infection and subsequent control of nosocomial legionellosis. In association with an unusual cluster of nosocomial pneumonia with Legionella in a tertiary-care hospital, we performed an environmental surveillance with molecular epidemiological study of Legionella isolates. METHODS: We randomly collected 20 samples of environmental and portable water from the hospital where three cases of Legionella pneumonia occurred consecutively during the period of 5 months. We detected Legionella from the samples by using both culture and polymerase chain reaction(PCR), and analyzed Legionella isolates from patients and environmental samples together with 12 reference strains by ribotyping using HpaI and EcoRI. RESULTS: Legionella was isolated from 3 out of 20(15%) samples by culture, and detected in 9 of 20(45%) by PCR. Ribotyping analysis showed that 2 patients' and 2 environmental isolates from a faucet of the patient's room and an air handling unit shared the same pattern which was also identical to that of Legionella pneumophila serogroup 6, a reference strain. CONCLUSION: The study showed that the hospital environments were contaminated with at least 2 Legionella species including L. pneumophila serogroup 6, and indicated that an unusual cluster of Legionella pneumonia occurred in the hospital was possibly linked to the contamination of a faucet with L. pneumophila serogroup 6.
Environmental Monitoring ; Epidemiologic Studies* ; Humans ; Legionella pneumophila ; Legionella* ; Legionellosis ; Pneumonia* ; Polymerase Chain Reaction ; Ribotyping ; Water

BACKGROUND: To prevent and control legionellosis outbreaks, it is important to monitor cooling towers for Legionella and establish epidemiological markers. We determined level of contamination with Legionella of cooling tower in Seoul city, analyzed the distribution of Legionella subtypes, and evaluated molecular typing methods for discrimination power and feasibility. METHODS: Water samples from 120 cooling towers in 25 areas(Gu) of Seoul city were collected during June, 1997. Culture and duplex-PCR(polymerase chain reaction) with Southern hybridization probed with Legionella-specific genes were performed with filtered samples. Twenty-two Legionella isolates were analyzed comparatively by pulsed-field gel electrophoresis(PFGE) and arbitrarily primed(AP)-PCR using a M13 reverse primer. RESULTS: Culture and duplex-PCR with Southern hybridization were positive for Legionella in 22(18.3%) and 106(88.3%) of 120 samples, respectively, resulting in 90.8%(109/120) of contamination level. Out of 22 Legionella isolates, 17 were identified as Legionella pneumophila serogroup 1, 4 as L. pneumophila serogroup 6 and 1 as an unknown. Molecular analysis of 17 isolates of L. pneumophila serogroup 1 showed 7 subtypes by PFGE(A0 in 9 isolates; A1, 2; A2, 1; A3, 2; B, 1; C, 1; D, 1) and 5 subtypes by AP-PCR(Ia in 11 isolates; Ib, 2; Ic, 2; II, 1; III, 1). The agreement of results of both methods was 76.5%(13/17) of L. pneumophila serogroup 1 and 81.8%(18/22) of all isolates, respectively. CONCLUSION: Most of cooling towers in Seoul city were already contaminated with Legionella just before summer, requiring decontamination measures and continuous surveillance. L. pneumophila serogroup 1 was the predominant isolate with variable subtypes. The AP-PCR can be used as a rapid and reproducible screening tool in tracking legionellosis outbreak.
Decontamination ; Discrimination (Psychology) ; Disease Outbreaks ; Legionella pneumophila ; Legionella* ; Legionellosis ; Mass Screening ; Molecular Typing ; Seoul* ; Water*

BACKGROUND: The frequent outbreak of legionellosis makes it critical to identify infection sources for the prevention and blockade of transmission of the disease. METHODS: Thirty-one strains of Legionella pneumophila isolated from the cooling towers of big buildings in Busan and Gyungsangnamdo Province areas, 12 strains of L. pneumophila from patients in Japan, and one type strain (L. pneumophila ATCC 33152) were used for molecular strain typing by using an infrequent-restriction-site polymerase chain reaction (IRS-PCR). RESULTS: Each strain revealed to have 7-16 bands of 200-1000 bp size. All 44 strains showed band patterns different from each other, except two strains sharing 90% homology. CONCLUSION: The molecular typing of Legionellaby IRS-PCR is an excellent and rapid method for discriminating strains; therefore, it should be useful in demonstrating the identity of possible outbreak strains.
Busan ; Humans ; Japan ; Legionella pneumophila* ; Legionella* ; Legionellosis ; Molecular Typing ; Polymerase Chain Reaction*

Legionella is a pathogenic bacteria associated to aquatic habit of natural and artificial environments. Clinical cases of legionellosis have been reported in Korea but there is a lack of information about the incidence of this bacterium on environmental sources. Thus, we investigated the contamination of Legionella on water supply systems in Gwangju, Korea, including cooling towers, public baths, hospitals and fountains. Legionella spp. were detected from 81 samples (16.9%) out of 480 samples collected and the major species of Legionella isolates was identified to L. pneumophila serogroup (sg) 1 (n=33). The result of PFGE pattern analysis for L. pneumophila sg 1 isolates was discriminated into 11 pulsotypes. In dendrogram of PFGE, the clusters of isolates from cooling tower were quite different from those derived from hot water system of public bath. Surveillance for 4 sentinel public baths showed that their water supply systems had been contaminated with Legionella spp. and L. pneumophila sg 5 or sg 6 was the major isolate. The similarity of its PFGE patterns was 92.3%, 96.6%, respectively. Thus, PFGE may be a useful tool in molecular epidemiology studies, and the monitor and control for water supply systems of public utilizing facilities will be able to provide a resolution for the reduction of Legionella infection.
Bacteria ; Baths ; Incidence ; Korea ; Legionella ; Legionellosis ; Molecular Epidemiology ; Nitriles ; Organothiophosphorus Compounds ; Pyrethrins ; Water ; Water Supply

Legionella is a pathogenic bacteria associated to aquatic habit of natural and artificial environments. Clinical cases of legionellosis have been reported in Korea but there is a lack of information about the incidence of this bacterium on environmental sources. Thus, we investigated the contamination of Legionella on water supply systems in Gwangju, Korea, including cooling towers, public baths, hospitals and fountains. Legionella spp. were detected from 81 samples (16.9%) out of 480 samples collected and the major species of Legionella isolates was identified to L. pneumophila serogroup (sg) 1 (n=33). The result of PFGE pattern analysis for L. pneumophila sg 1 isolates was discriminated into 11 pulsotypes. In dendrogram of PFGE, the clusters of isolates from cooling tower were quite different from those derived from hot water system of public bath. Surveillance for 4 sentinel public baths showed that their water supply systems had been contaminated with Legionella spp. and L. pneumophila sg 5 or sg 6 was the major isolate. The similarity of its PFGE patterns was 92.3%, 96.6%, respectively. Thus, PFGE may be a useful tool in molecular epidemiology studies, and the monitor and control for water supply systems of public utilizing facilities will be able to provide a resolution for the reduction of Legionella infection.
Bacteria ; Baths ; Incidence ; Korea ; Legionella ; Legionellosis ; Molecular Epidemiology ; Nitriles ; Organothiophosphorus Compounds ; Pyrethrins ; Water ; Water Supply

As a type of
Humans ; Legionella/genetics* ; Legionella longbeachae/genetics* ; Legionellosis/drug therapy* ; Pneumonia/diagnosis* ; Retrospective Studies

The genus Legionella is common in aquatic environments. Some species of Legionella are recognized as potential opportunistic pathogens for human, notably Legionella pneumophila that causes Legionellosis. During the summer season between June and August in 2010, we isolated 61 L. pneumophila from the bath facilities of public establishments of 25 wards in Seoul. The existence of 16S rRNA and mip gene of L. pneumophila was confirmed in the genome of the isolated strains by PCR. Among the 61 strains of L. pneumophila, thirty three isolates belong to serogroup 1 (54.1%), 13 isolates were serogroup 6 (21.3%), 9 isolates were serogroup 5 (14.8%), 3 isolates were serogroup 3 (4.9%), and 3 isolates were identified in serogroup 2 (4.9%). On pulsed-field gel electrophoresis (PFGE) analysis using SfiI, genetic types of L. pneumophila were classified into 8 (A to H) patterns by the band similarity with excess of 65%. Our results suggest the existence of serological and genetic diversity among the L. pneumophila isolates.
Baths ; Electrophoresis, Gel, Pulsed-Field ; Genetic Variation ; Genome ; Humans ; Legionella ; Legionella pneumophila ; Legionellosis ; Molecular Epidemiology ; Polymerase Chain Reaction ; Seasons

Building-related illness is an increasingly common problem. The disease fall into two categories : those that have an identifiable cause-such as legionellosis, humidifier fever, and conditions resulting from exposure to known substances such as asbestos, lead in paint, formaldehyde, etc-and those that have no readily identifiable cause but can be described only by a group of symptoms known as sick building syndrome (SBS). Although objective physiologic abnormalities are generally not found and permanent sequelae are rare, the symptoms of SBS can be uncomfortable, even disabling, and whole workplaces may be rendered non-functional. In assessment of patients with SBS complaints, specific building-related illnesses should be ruled out by history or physical examination. On-site assessment of buildings is extremely useful. Symptoms of non-specific building-related illnesses are common ; their heterogeneity suggests that they do not represent a single disorder. Although there is little convincing, direct evidence to implicate specific causative agents, there is sufficient indirect evidence to support a number of recommendations. For example, it seems prudent to maintain an outdoor-air supply of more than 10 liters per second per person ; to select the building materials, furnishings, and equipments that are least likely to release pollutants such as formaldehyde or volatile organic compounds ; to ensure proper maintenance and cleaning ; and to avoid materials that may act as substrates for the proliferation of microbes or dust mites.
Asbestos ; Construction Materials ; Dust ; Fever ; Formaldehyde ; Humans ; Humidifiers ; Legionellosis ; Mites ; Paint ; Physical Examination ; Population Characteristics ; Sick Building Syndrome ; Volatile Organic Compounds