• Journal of Microbiology and Biotechnology
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• 제9권3호
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• pp.371-375
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• 1999

AL072 is a potent anti-Legionella antibiotic produced by Streptomyces strain AL91. The minimum inhibitory concentration (MIC) of AL072 against Legionella pneumophila was 0.2$\mu$g/ml. Bacterial growth was rapidly inhibited at the dose range between the MIC and 20 times of the MIC when the antibiotic was added at the mid-exponential phase. Ultrastructural changes in L. pneumophila were observed upon treatment with AL072. Under electron microscopical observation, the organisms treated with AL072 exhibited characteristic morphological changes in the cellular outer coat. Also irregular morphological changes, such as the formation of filamentous materials in the cytoplasm, an increase in the size and number of cytoplasmic vacuoles, the extruding of cytoplasmic contents, the formation of spheroplast and ghost cells, and blebbings in the cell wall were observed. Furthermore, immunoelectron microscopical observation of the group treated with the MIC showed that the immune complex attached mainly to the cell wall. The results of these experiments indicate that AL072, like the inhibitors of cell wall synthesis, act selectively on the cell wall of L. pneumophila.

• The Journal of the Korean Society for Microbiology
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• 제21권1호
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• pp.107-111
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• 1986

An outbreak of Pontiac fever was reported in Seoul in 1984, but legionnaires disease was not known in Korea yet. Our knowledge on the presence or abscence of Legionella in cooling tower. which is the main source of the infection. is very limited. In this study an attempt was made to determine the presence of Legionella in cooling towers during June-September. and in the sputum specimens for routine bacteria culture, which was taken during July-August 1985. Among the 83 water samples 6 yielded L. pneumophila serogroup 1, while none of the 189 sputum samples yielded growth of Legionella. It is concluded that legionellosis can occur in Korea and if it happens it is most likely due to L. pneumophila serogroup 1.

• Tuberculosis and Respiratory Diseases
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• 제50권4호
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• pp.409-414
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• 2001

Background : Legionella pneumophila has been recognized as an important cause of community-acquired pneumonia(CAP) requiring hospitalization. However, epidemiological data on the occurrence of legionella-related pneumonia is unavailable in Korea. The purpose of this study was to evaluate the etiological importance of legionella pneumophila serogroup 1 in patients hospitalized with CAP. Method : The CAP patients over 16 year-old were recruited from July 1999 to June 2000 at the Chunchon Sacred Heart Hospital. Fifty four patients (male 29, female 25, average age $63.8{\pm}15.3$) were included in this study. A diagnosis of a legionella pneumophila infection was based on a urinary antigen test using the Binax Company enzyme immunoassay. The severity of pneumonia was assessed using the Fine's PORT scoring system. Result : The average Fine's PORT score was 99.7(${\pm}44.9$). According to the risk classification proposed by the Infectious Disease Society of America, the number of patients in each class(from class I to class V) were 6(11.1%), 13(24.1%), 9(16.7%), 14(25.8%), and 12(22.2%), respectively. Thirty two patients(59.3%) were initially admitted to the intensive care unit. The mortality rate was 16.7%(9 in 54). In all patients, urinary antigens to Legionella pnewnophila serogroup 1 were not detected. Conclusion : Legionella pnewnophila may play little role in causing adult CAP in Korea. Therefore, the routine use of macrolide in the empirical treatment of the CAP patients based upon the ATS guidelines(1993) in Korea should be reevaluated.

• Microbiology and Biotechnology Letters
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• 제43권3호
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• pp.259-266
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• 2015

Observed trends in climate change, globalization and an aging population have an effect on public health conditions in Korea, prompting a reevaluation of current environmental regulations. In this study, we evaluated the performance of the total coliform (TC) standard, which is the only microbiological standard in the current regulation regime for hot spring water, by estimating correlation with the presence/absence of Legionella, a non-fecal opportunistic pathogen with heat-tolerance. Microbiological data in 7 studies that surveyed Legionella in hot spring waters were subjected to meta-analyses with the odds ratio (OR) as the effect size. The presence/absence of Legionella was significantly correlated to TC levels [OR = 3.1(1.5–6.4, 95% CI), p = 0.002]. Due to there being no direct explanation as to the reason for the occurrence of TC, mesophilic fecal bacteria, being coupled with Legionella presence, the mechanism of the correlation between the two kinds of bacteria was further investigated. Legionella presence was more prevalent with a high heterotrophic plate count [HPC; 4.0(2.2–7.2); p < 0.001] and water temperature [4.3(1.4–13.6), p = 0.011] when the temperature range was <40℃. However, it was reverse-correlated with water temperature when the temperature was >50℃ [0.2(0.1–0.4), p < 0.001]. Therefore, bacterial standing crops in hot spring waters appear to be determined by water temperature in general, and this forces TC and Legionella levels be correlated. In accordance with this relationship, HPC rather than TC reflect the levels of non-fecal contamination better. Therefore, employing HPC as the sole microbiological standard, or adding HPC into the current standard of hot spring water assessment, is suggested as a proactive measure to prevent health issues arising from contamination.

• Korean Journal of Microbiology
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• 제53권3호
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• pp.156-162
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• 2017

Legionnaires' disease (LD) is a severe and potentially fatal pneumonia caused by colonization of human-made water system and subsequent aerosolization and inhalation of Legionella bacteria. A total of 147 Legionella strains was isolated from environmental water sources from public facilities in Gyeonggi-do, South Korea. The distribution of Legionella isolates was investigated according to facility type, and sample type. L. pneumophila was distributed broadly throughout Gyeonggi-do, accounting for 85.7% of the isolates, and L. pneumophila serogroup (sg) 1 predominated in all of the public facilities. L. wadsworthii predominated among non-L. pneumophila species. We performed comparative analyses of L. pneumophila sg 1 isolated from environment water of public facilities in Gyeonggi-do by pulsed field gel electrophoresis (PFGE) and sequence-based typing (SBT). Thirty-two isolates were classified into 22 types by PFGE and 9 sequence types (STs) by SBT and categorized into 3 groups. ST1 was the most prevalent sequence type and two STs obtained in this study had unique allelic profiles. The use of SBT data from different countries for epidemiology study of LD constitutes a technically uncomplicated and relatively easy method for strain subtyping, especially compared to other contemporary techniques.

• Journal of Environmental Health Sciences
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• 제39권2호
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• pp.166-177
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• 2013

Objectives: 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. Thus, we investigated the contamination of Legionella pneumophila on water supply systems in Seoul, including cooling towers, public baths, hospitals and fountains. Methods: The existence of 16S rRNA and mip gene of L. pneumophila was confirmed in the genome of the isolated strains by PCR. Results: During the summer season of 2010 and 2011, Legionella pneumophila were detected from 163 samples (21.1%) out of 772 samples collected. Among the 163 strains of L. pneumophila, eighty one isolates belonged to serogroup 1 (57.4%), 23 isolates were serogroup 5 (16.3%), 21 isolates were serogroup 6 (14.9%), 8 isolates were serogroup 2 (5.79%), and 8 isolates were identified in serogroup 3 (5.7%). Through PFGE (pulsed-field gel electrophoresis) analysis using Sfi I, genetic types of L. pneumophila were classified into five (A to E) patterns by the band similarity with excess of 70% from public baths. Conclusions: The PFGE patterns of the serotypes showed a tendency for diversity of L. pneumophila. Our results suggest the existence of serological and genetic diversity among the L. pneumophila isolates.

• Journal of Preventive Medicine and Public Health
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• 제50권4호
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• pp.274-277
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• 2017

Objectives: Legionnaires' disease (LD) is a severe type of pneumonia caused by inhalation of aerosols contaminated with Legionella. On September 22, 2016, a single case of LD was reported from a newly built apartment building in Gyeonggi province. This article describes an epidemiologic investigation of LD and identification of the possible source of infection. Methods: To identify the source of LD, we interviewed the patient's husband using a questionnaire based on the Legionella management guidelines from the Korea Centers for Disease Control and Prevention. Water samples from the site were collected and analyzed. An epidemiological investigation of the residents and visitors in the apartment building was conducted for 14 days before the index patient's symptoms first appeared to 14 days after the implementation of environmental control measures. Results: Legionella pneumophila serogroup 1 was isolated from the heated-water samples from the patient's residence and the basement of the apartment complex. Thirty-two suspected cases were reported from the apartment building during the surveillance period, yet all were confirmed negative based on urinary antigen tests. Conclusions: The likely source of infection was the building's potable water, particularly heated water. Further study of effective monitoring systems in heated potable water should be considered.

• Applied Chemistry for Engineering
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• 제25권5호
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• pp.544-547
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• 2014

In this study, an enzyme-linked immunosorbent assay (ELISA) and immuno-chromatographic technique were combined to fabricate immuno-strip sensors for the detection of Legionella pneumophila. The immuno-strip sensor was manufactured with four different membranes. A nitrocellulose membrane was used to immobilize capture antibody and generate signals due to the high affinity to antibodies, and glass fiber membranes were used as a conjugate release pad and a sample application pad. A cellulose membrane was used as an absorption pad to induce sample flow by the capillarity. Colorimetric signals produced by sandwich immuno-reaction and enzyme reaction could be analyzed qualitatively and quantitatively within 30 min. Under the given experimental conditions, sensor signals with L. pneumophila samples were observed qualitatively by naked eyes and measured quantitatively in a range of $1.3{\times}10^3-1.3{\times}10^6CFU/mL$ with a digital camera and home-made image analysis software.

• Microbiology and Biotechnology Letters
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• 제29권3호
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• pp.127-133
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• 2001

Pseudomonas aeruginosa KLP-2 possessing antimicro- bial activity against Legionella pneumophila was isolated from cooling tower-waters. The culture filtrates of P. aeruginosa KLP-2 showed antimicrobial activity against L. pneumophila Vibro cholerae non-Ol. Bacillus cereus, Bacillus subtilis and staphylococcus aureus. The culture filtrates of P. aeruginosa KLP-2 showed the highest anti-microbial activity against. L pneumophila among micoorganisms tested in this study. The optimal conditions of temperature, pH carbon source and nitogen source to obtain maximal antimicrobial activity from culture filtrates of P. aeruginosa KLP-2 were determined to be 35$^{\circ}C$ pH 7.0 % of glycerol and 0.6% of proteose peptone respec- tively. The antimicrobial activity of culture filtrates from P. seruginosa KLP-2 was highest against L. pneumophila when cultivated with shaking for 24 h and without shaking for 4 day at 35$^{\circ}C$.

• Journal of Environmental Health Sciences
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• 제28권3호
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• pp.39-48
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• 2002

Cooling towers water has frequently been known as a source of infection in outbreaks of Legionnaires' disease and a source of indoor air pollution. However, there have been a few reports on the presence of Legionella in cooling towers water and aerosols of various public facilities. This study was carried out to investigate the indoor and outdoor dis-tribution of Legionella spp and microbe from 132 cooling towers water of public facilities detected 1. pneumophila in Seoul and Gyeonggi-Do areas. The results showed that the Lpneumophila among the selected 132 cooling towers was detected mostly in July (12.0%), followed by August (4.0%) and June, September no-detected. The 1. pneumophiia in public facilities was detected mostly in department store (27.3%), followed by hospital (8.7%), office building (5.9%), big market (5.0%) and hotel, subway no-detected. The pH values of cooling towers water with presence of 1. pneumophila showed mostly 8.0 or higher (9.5%), followed by 7.0～8.0 (6.8%), lower 7.0 no-detected. The tem-perature of cooling towers water with presence of L pnemophila showed mostly 30℃ or higher (9.8%), followed by 26～30℃ (6.9%), lower 25℃ no-detected. The turbidity of cooling towers water with presence of 1. pneumaphila showed mostly 1-2 M (8.8%), followed by above 2 NTU (5.9%), lower 1 NTU no-detected. The correlation coef-ficient between indoor and outdoor concentration of microbes in public facilities showed 0.67 in Legionella spy. (p>0.05), 0.93 in bacteria (p<0.01), 0.94 in fungus (p<0.01), 0.98 in coilform (p<0.01), respectively.