• Genomics & Informatics
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• 제12권4호
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• pp.268-275
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• 2014

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.

• 한국환경보건학회지
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• 제47권5호
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• pp.472-478
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• 2021

Background: The Legionella case detection and notification rate have increased in public artificial water environments where people visit, including large buildings, public baths, and hospitals. Objectives: In this study, the distribution of Legionella and its epidemiologic characteristics were analyzed in the water systems of public facilities in Chungcheongnam-do Province in South Korea. Methods: Culture and PCR analysis were performed on 2,991 environmental water system samples collected from 2017 to 2019, and associations with year, facilities, seasons, and temperature of water system were statistically analyzed by using R-Studio for Windows. Descriptive data was compared using chi-square tests and independent t-tests. Results: The detection rate of Legionella increased from 3.1% in 2017 to 10.3% in 2019, appearing most frequently in the order of public baths, large-scale buildings, hospitals, and apartments. It was detected mainly in summer from June to August, over 1.0×10³ CFU/L on average in 133 cases (66.5%). Lots of germs were detected in bathtub water, cooling tower water, and warm water (p<0.001), and it was detected at higher rates in the cities where multipurpose facilities were concentrated than in rural areas (p=0.018). Conclusions: This study suggests that continuous monitoring and control are required for Legionella in the water system environment of high risk facilities. Moreover, these results will be helpful to prepare efficient management plans to prevent the Legionellosis that occurs in Chungcheongnam-do Province.

• 대한미생물학회지
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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.

• Journal of Preventive Medicine and Public Health
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• 제45권1호
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• pp.1-7
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• 2012

Using three Austrian case studies, the variegated applications of molecular typing in today's public health laboratories are discussed to help illustrate preventive management strategies relying on DNA subtyping. DNA macrorestriction analysis by pulsed field gel electrophoresis has become the gold standard for subtyping of food borne pathogens like listeria, salmonella, campylobacter and Bacillus cereus. Using a Salmonella Mbandaka outbreak from the year 2010 as example, it is shown how the comparison of patterns from human isolates, food isolates, animal isolates and feed isolates can allow to identify and confirm a source of disease. An epidemiological connection between the simultaneous occurrence of tuberculosis in cattle and deer with cases of human tuberculosis due to Mycobacterium caprae in 2010 was excluded using mycobacterial interspersed repetitive units variable-number tandem repeats subtyping. Also in 2010, multilocus sequence typing with nonselective housekeeping genes, the so-called sequence based typing protocol, was used to elucidate connections between an environmental source (a hospital drinking water system) and a case of legionellosis. During the last decades, molecular typing has evolved to become a routine tool in the daily work of public health laboratories. The challenge is now no longer to simply type microorganisms, but to type them in a way that allows for data exchange between public health laboratories all over the world.

• Journal of Preventive Medicine and Public Health
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• 제31권3호
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• pp.540-563
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• 1998

This Study has been carried out to make a recommendation for the next amendment of the Infectious Disease Prevention Act with a specific focus on the kind of notifyable disease. Korean, Japanese, German, U.S, English and French acts on infectious diseases prevention were reviewed, compared with and analized in regards of numbers and kinds of notifyable infectious diseases and their tendency of amendments. An criteria was designed to assess the level of validity of diseases to be designated in the act. Four items, the fatality (greater than 10% or not), the possibility to make a big epidemic, the availability of efficient vaccination and the usefulness of isolation, are used in the assessment. This index is applied to the diseases in Korean and other countries' Infectious Disease Prevention Acts. Results are as follows: 1. The Korean Infectious Disease Preventon Act has a unique way of classifying the notifyable infectious disease, that is, the first, the second and the third class. But the author cannot find the basis of classification. No other countries reviewed have the similar classification. 2. The ten diseases, cholera, plague, yellow fever, diphtheria, typhoid fever, poliomyelitis, rabies, tetanus, malaria, and meningococcal meningitis are designated as the notifyable diseases not only in Korea but also in Japan, Germany, United States, England and france. 3. Thirty seven diseases including small pox, Lassa fever, anthrax, influenza, German measles, Legionellosis, infection with E. coli O157:H7, Q-fever, brucellosis, Lyme disease are designated as legal disease at least one of the above mentioned countries. 4. The Korea has been coped with the change of the infectious disease occurrence for last fifty years in amendment of the Infectious Disease Prevention Act. 5. Japan has a special infectious surveillance system composed of 3,880 clinics throughout the whole country. 6. Germany has classified infectious diseases in five categories which are based on seriousness of disease. Any confirmed death, cases and suspected cases in class I should be reported within 24 hours. But only confirmed death and cases in class II, but not suspected cases, are reportable in Germarny. 7. Plague, bacillary dysentery, pertussis, mumps, Japanese encephaltis and Korean hemorrhagic fevers are diseases with high credits validity index among Korean legal disease. 8. German measles, anthrax, E. coli O157 : H7 infection, Lassa fever, Q-fever, brucellosis are high in validity index among those which are not designated in Korea but designated in other countries. In conclusion, the Korean Infectious Disease Prevention Act has well been coped with the changes of infectious disease occurrence for last fifty years, but the classification basis and the validity of diseases to be designated as legal diseases is worth reevaluating.

• Journal of Microbiology and Biotechnology
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• 제12권1호
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• pp.114-120
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• 2002

A 1,989-bp genomic region encoding nickel resistance genes was isolated from Legionella pneumophila, a pathogen for legionellosis. From a sequencing and computer analysis, the region was found to harbor two structural genes, a nreB-like protein gene (1,149 bp) and a nreA-like protein gene (270 bp), in a row. Both genes exhibited a significant degree of similarity to the corresponding genes from Synechocystis sp. PCC6803 ($54\%$ amino acid sequence identity) and Achromobacter xylosoxidans 31A ($76\%$). The gene was successfully expressed in E. coli MG1655 and conferred a nickel resistance of up to 5 mM in an LB medium and 3 mM in a TMS medium including gluconate as the sole carbon source. E. coli harboring the nickel resistance gene also exhibited a substantial resistance to cobalt, yet no resistance to cadmium or zinc. Since the extracellular concentration of nickel remained constant during the whole period of cultivation, it was confirmed that the nickel resistance was provided by an efflux system like the $Ni^2＋$permease (nrsD) of Synechocystis sp. strain PCC6803. Since polyphosphate (poly-P) is known as a global regulator for gene expression as well as a potential virulence factor in E. coli, the nickel resistance of a ppk mutant of E. coli MG 1655 harboring the nickel resistance gene from L. pneumophila was compared with that of its parental strain. The nickel resistance was significantly attenuated by ppk inactivation, which was more pronounced in an LB medium than in a TMS medium.

• 한국환경보건학회지
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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.

• 미생물학회지
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• 제45권2호
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• pp.126-132
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• 2009

레지오넬라균은 치명적인 폐렴을 일으킬 수 있는 균으로서, 기후 온난화와 함께 노출의 수위가 높아지고 있는 병원성균이다. 본 연구는 2008년 6월부터 8월까지 서울시내 25개구 소재 수계시설에서 분리한 레지오넬라균 73개 주에 대해 혈청형, Dot/Icm라 일컬어지는 병원성 유전자 분석 그리고 Pulsed field gel electrophoresis (PFGE)를 실시하여 유전자형과 그들 사이의 상관관계를 파악하였다. 73개주 중 69주는 Legionella pneumophila로 혈청형의 분포는 sg1 43주, sg6 9주, sg5 8주, sg3 8주, sg2 1주로 파악되었으며, Legionella spp. 4개주는 Legionella nautarum였다. 분리된 Legionella pneumophila 대부분이 여러 개의 병원성 유전자를 보유하고 있었으며, 반면에 Legionella nautarum은 병원성 유전자가 많이 결핍되어있었다. PFGE pattern을 분석해 볼 때, Legionella pneumophila가 동일한 혈청형안에서 다양하게 분화되어감을 볼 수 있었으며, 병원성 유전자의 분포와 깊은 상관관계를 보였다.