바닥분수에서 물놀이를 하는 아동들의 Legionella균 감염 위해도 분석

이인섭,조영근,Lee, In-Sup,Zo, Young-Gun 한국미생물학회 2013 미생물학회지 Vol.49 No.4

최근 국내의 각종 시설들에서 경관과 여름철 물놀이를 위한 바닥분수 설치가 선호되어, 그 수가 연간 50% 이상 급증하고 있다. 본 연구는, 정량적 미생물학적 위해성 평가 방법으로, 아동이 바닥분수에서 물놀이를 하는 동안 Legionella spp.에 의한 감염 위해도가 어느 정도인지 정량 하였다. 용수 중 Legionella균의 농도를 $10^{-1}-10^6$ CFU/L로 상정하고, 공기 중으로 에어로졸과 함께 비산하게 되는 Legionella균의 농도와 노출시간, 호흡률의 분포, 폐까지 도달하는 에어로졸의 비율을 곱하여 아동들의 노출량을 산정하고, Legionella pneumophila의 위해도를 도출하는 것으로 알려진 지수함수 모델에 따라, 감염 위해도로 변환하였다. 최고 위험군은 뛰어다니면서 물놀이를 하는 신체가 큰, 혹은 연령이 높은 아동이었으며, 이들이 $10^4$ CFU/L 이상의 Legionella균이 존재하는 분수 용수를 1회 이상 이용 시 0.05 이상의 위해도가 발생하였다. 이 결과에 따르면, $10^3$ CFU/L 미만의 Legionella균 농도를 공중이용시설의 모든 배관용수에 대하여 허용하는 현행 질병관리본부의 레지오넬라증 관리지침은 타당한 것으로 판정된다. 그러나, 이 기준은 건강한 성인 대상으로는 적합하나 아동의 면역력이 낮은 점을 감안하지 않았으므로, 아동에게 적합한 감염위해도 모델을 연구하여, 보다 철저한 관리 기준을 적용할 필요성이 있다. Recently interactive water fountains are gaining popularity in making public facilities in South Korea. The total number of interactive fountains is rapidly growing at the rate of >50% annually. In this study, we performed quantitative microbial risk assessment to estimate infection risks in children by Legionella spp. while playing in interactive fountains. The exposure dose for a given concentration of Legionella in water was calculated using water-aerosol partition rate of Legionella, exposure duration, inhalation rate, and deposit rate of aerosols in the lungs following inhalation. The dose was converted to infection risk by using the dose-response function developed for L. pneumophila. High weight and/or old children, i.e., 12-year children, running around in fountains were the highest risk group by showing >0.05 infection probability for fountain waters containing ${\geq}10^4$ CFU/L Legionella. The result supported the current guideline by Korea Centers for Disease Control and Prevention, which permits use of water with < $10^3$ CFU/L Legionella cells for all purposes. However, the results still warrant further evaluation of the guideline to accommodate risks for children because the dose-response relationship in the model was developed for healthy adults. Further risk assessment studies need to be conducted by employing dose-response model for children who generally carries weaker immune system than adults.

Innate immunity against Legionella pneumophila during pulmonary infections in mice

박봉규,박가영,김지영,임선아,이경미 대한약학회 2017 Archives of Pharmacal Research Vol.40 No.2

Legionella pneumophila is an etiological agentof the severe pneumonia known as Legionnaires’ disease(LD). This gram-negative bacterium is thought toreplicate naturally in various freshwater amoebae, but alsoreplicates in human alveolar macrophages. Inside hostcells, legionella induce the production of non-endosomalreplicative phagosomes by injecting effector proteins intothe cytosol. Innate immune responses are first line defensesagainst legionella during early phases of infection, anddistinguish between legionella and host cells using germline-encoded pattern recognition receptors such as Toll-likereceptors , NOD-like receptors, and RIG-I-like receptors,which sense pathogen-associated molecular patterns thatare absent in host cells. During pulmonary legionellainfections, various inflammatory cells such as macrophages,neutrophils, natural killer (NK) cells, largemononuclear cells, B cells, and CD4? and CD8? T cellsare recruited into infected lungs, and predominantly occupyinterstitial areas to control legionella. During pulmonarylegionella infections, the interplay between distinctcytokines and chemokines also modulates innate hostresponses to clear legionella from the lungs. Recognitionby NK cell receptors triggers effector functions includingsecretion of cytokines and chemokines, and leads to lysis oftarget cells. Crosstalk between NK cells and dendritic cells,monocytes, and macrophages provides a major first-linedefense against legionella infection, whereas activation ofT and B cells resolves the infection and mounts legionellaspecificmemory in the host.

일부 대중 목욕탕 욕수의 레지오넬라균 분포실태 및 혈청학적 특성

김영환(YoungWhan Kim),문경환(KyongWhan Moon),이장희(JangHee Lee),조일형(IlHyung Cho),김미라(MiRa Kim) 고려대학교 보건과학연구소 2004 보건과학논집 Vol.30 No.1

This study was to determine the prevalence of Legionella species in public spas and to know that the presence of Legionella was correlated with other microbiological parameters. A total of 81 water samples were collected from 30 different public spas and sudatoriums so called zzimzilbang in Korea. Although Legionella was not detected in raw water(tap water) and the cold tub water, of the 38 samples of hot and warm water taken from public tubs, 11 samples(28.8%) were found to be positive for Legionella spp. All of the isolates were identified as a species L. pneumophila serogroups 1 and 2-14 by latex agglutination. The levels of L. pneumophila were fairly distributed over a broad range of concentrations from <10² cfu/㎖ to 10⁴ /㎖, with 1 of a spas in the <100 cfu/㎖, 4 spas in the 10² to 10³ cfu/㎖, and 2 spas had levels of culturable L. pneumophila. >104 cfu/㎖. And HPC concentrations in all spa waters isolated Legionella were above the level of 104 cfu/ml. Total coliforms were detected in 45% of the samples and were grew in even raw water. But total coliform was not detected in the majority of Legionella-positive samples. The correlation between the presence of Legionella and total coliforms was not showed in the tub water. On the basis of these results, it would appeared that Legionella proliferate primarily in inadequate tubs to control the total bacteria numbers.

Screening-Level Assays for Potentially Human-Infectious Environmental Legionella spp.

Helen Y. Buse,Abby Brehm,Jorge W. Santo Domingo,Nicholas J. Ashbolt 한국미생물학회 2011 The journal of microbiology Vol.49 No.2

In spite of the fact that various Legionella species are isolated from nonclinical water settings, there is no standard method to determine whether environmental legionellae may be infectious to humans. Here we provide a screening-level approach based on an in vivo murine (A/J mouse) model and three in vitro proliferation assays using Acanthamoeba polyphaga, and THP-1 human and J774 murine macrophage cell lines to identify potentially human-infectious legionellae. As an initial demonstration the infectivity potential of three clinical (Legionella pneumophila, L. longbeacheae, and L. micdadei) and three environmental (L. dumoffii, L. maceachernii, and L. sainthelensi) legionellae were evaluated. A/J mice were intranasally infected and by 6 h post infection (p.i.), there were significant bacterial titers in the lungs. L. pneumophila,L. dumoffii, and L. micdadei densities were higher than L. longbeacheae, L. maceacherni, and L. sainthelensi at 24 h p.i. However, only L. pneumophila and L. micdadei persisted in the lungs after 48 h, indicating that the other isolates were rapidly cleared. Results from the in vitro assays showed that only L. pneumophila significantly multiplied within A. polyphaga, THP-1 and J774 cells after 72 h, but lysis of any of the in vitro hosts also flagged the strains for potential concern (e.g. L. dumoffii and L. micdadei). The results demonstrate the value of using multiple approaches to assess the potential level of pathogenicity of Legionella strains isolated from different environmental matrices.

레지오넬라균 출현위해도에 대한 현행 온천수 수질기준의 적합성 분석

김진남 ( Jinnam Kim ),이소영 ( Soyoung Lee ),조영근 ( Younggun Zo ) 한국미생물생명공학회(구 한국산업미생물학회) 2015 한국미생물·생명공학회지 Vol.43 No.3

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 <40oC. However, it was reverse-correlated with water temperature when the temperature was >50oC [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.

Application of Multilocus Sequence Analysis (MLSA) for Accurate Identification of Legionella spp. Isolated from Municipal Fountains in Chengdu, China, Based on 16S rRNA, mip, and rpoB Genes

Wang Guan,Ying Xu,Da-li Chen,Jia-nan Xu,Yu Tian,Jian-ping Chen 한국미생물학회 2012 The journal of microbiology Vol.50 No.1

Legionellosis (Legionnaires’ disease; LD) is a form of severe pneumonia caused by species of Legionella bacteria. Because inhalation of Legionella-contaminated aerosol is considered the major infection route, routine assessments of potential infection sources such as hot water systems, air-conditioner cooling water, and municipal fountains are of great importance. In this study, we utilized in vitro culture and multilocus sequence analysis (MLSA) targeting 16S rRNA, mip, rpoB, and mip-rpoB concatenation to isolate and identify Legionella spp. from 5 municipal fountains in Chengdu City, Sichuan Province, China. Our results demonstrated that 16S rRNA was useful for initial identification, as it could recognize isolates robustly at the genus level, while the genes mip, rpoB, and mip-rpoB concatenation could confidently discriminate Legionella species. Notably, the three subspecies of L. pneumophila could be distinguished by the analysis based on rpoB. The serotyping result of strain CD-1 was consistent with genetic analysis based on the concatenation of mip and rpoB. Despite regular maintenance and sanitizing methods, 4 of the 5 municipal fountains investigated in this study were positive for Legionella contamination. Thus, regularly scheduled monitoring of municipal fountains is urgently needed as well as vigilant disinfection. Although the application of MLSA for inspection of potential sites of infection in public areas is not standard procedure, further investigations may prove its usefulness.

Real-time PCR을 이용한 환경 중 물 시료의 레지오넬라 분석법 연구

이정희,이정희,박명기,김윤성,윤희정,이창희,정아용,윤미혜 한국환경보건학회 2019 한국환경보건학회지 Vol.45 No.5

Objectives: The standard method for the enumeration of environmental Legionella is culturing, which has several disadvantages, including long incubation and poor sensitivity. The purpose of this study is to demonstrate the usefulness of real-time PCR and to improve the standard method. Methods: In 200 environmental water samples, a real-time PCR and culture were conducted to detect and quantify Legionella. Using with the results of the survey, we compared the real-time PCR with the culture. Results: Each real-time PCR assay had 100% specificity and excellent sensitivity (5 GU/reaction). In the culture, 36 samples were positive and 164 samples were negative. Based on the results of the culture, real-time PCR showed a high negative predictive value of 99%, 35 samples were true positive, 105 samples were true negative, 59 samples were false positive and one sample was a false negative. Quantitative analysis of the two methods indicated a weak linear correlation (r 2 =0.29, r 2 =0.61, respectively). Conclusions: Although it is difficult to directly apply quantitative analysis results of real-time PCR in the enumeration of environmental Legionella, it can be used as a complementary means of culturing to rapidly screen negative samples and to improve the accuracy of diagnosis.

Community-acquired Legionnaires' Disease in a Newly Constructed Apartment Building

Ryu, Sukhyun,Yang, Kyungho,Chun, Byung Chul The Korean Society for Preventive Medicine 2017 Journal of Preventive Medicine and Public Health Vol.50 No.4

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.

Community-acquired Legionnaires’ Disease in a Newly Constructed Apartment Building

유석현,양경호,천병철 대한예방의학회 2017 예방의학회지 Vol.50 No.4

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.

Ubiquitin-regulating effector proteins from Legionella

Minwoo Jeong,Hayoung Jeon,Donghyuk Shin 생화학분자생물학회 2022 BMB Reports Vol.55 No.7

Ubiquitin is relatively modest in size but involves almost entirecellular signaling pathways. The primary role of ubiquitin ismaintaining cellular protein homeostasis. Ubiquitination regulatesthe fate of target proteins using the proteasome- or autophagymediateddegradation of ubiquitinated substrates, which can beeither intracellular or foreign proteins from invading pathogens. Legionella, a gram-negative intracellular pathogen, hinders thehost-ubiquitin system by translocating hundreds of effector proteinsinto the host cell’s cytoplasm. In this review, we describethe current understanding of ubiquitin machinery from Legionella. We summarize structural and biochemical differences betweenthe host-ubiquitin system and ubiquitin-related effectors of Legionella. Some of these effectors act much like canonical host-ubiquitinmachinery, whereas others have distinctive structures andaccomplish non-canonical ubiquitination via novel biochemicalmechanisms.