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Contamination of Legionella Species in Water Distribution Systems in Hospitals and Genetic Diversity of Isolated Legionella Pneumophila Serogroup 1

Author: TaoLiLi
Tutor: HuBiJie;LiHuaYin;WangZuoQing;ChenXueHua
School: Fudan University
Course: Internal Medicine
Keywords: Legionella Water supply system Pollution Hospital Infection Environmental Monitoring Risk factors Legionella pneumophila Pulsed-field gel electrophoresis Virulence gene sequencing genotyping Repetitive sequence polymerase chain reaction Epidemiological investigation
CLC: R378
Type: Master's thesis
Year: 2010
Downloads: 45
Quote: 0
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Objective: to understand a Shanghai hospital water supply system piping Legionella and amoeba pollution and analysis of water supply systems contaminated with Legionella risk factors. Methods: From May to September 2009, collecting eight hospitals in Shanghai water supply system pipe end of the water samples a total of 193 copies of Legionella and amoeba culture and latex agglutination test for Legionella Legionella isolated serum genotyping. Detected in water samples were collected at the same time, the water sample temperature, pH, and other indicators collected hospital water supply system. Results: in a sampling of eight hospitals, seven hospitals have Legionella colonization, accounting for 87.5%. 5 Hospital Legionella colonization rate (62.5%) of the total of more than 30% of the two hospitals Legionella pneumophila colonization rate of over 30% (25.0% of the total). A total of 193 water samples, the genus Legionella culture-positive water samples of 83, the positive rate was 43.0%, including Legionella pneumophila positive water samples were 33, total 39.8% of the positive water samples. Amoeba culture-positive water samples of 166 copies, the positive rate was 86.0%. In Legionella-positive 83 water samples, concentrations of ≥ 103cfu / water sample for 63, accounting for 75.9% of the positive, the concentration of ≥ 104 cfu / l of water samples were 22, accounting for 26.5% of the positive one detected concentration of ≥ 105cfu / non-type 1 Legionella pneumophila in water samples. 26 water samples collected from the intensive care unit (ICU), 11 (42.3%) were detected Legionella detection of Legionella pneumophila in 6 (23.1%), 21 (80.8%) were detected in amoeba . ICU in all water samples detected Legionella concentrations ≥ 103cfu / 1,7 parts water samples Legionella concentrations ≥ cfu / 1. Legionella pollution risk factor analysis, amoeba colonization, water pipe the disinfected water pipes type of galvanized steel pipe and tank indirect water supply are independent risk factors. Conclusion: Shanghai hospital water systems contaminated with Legionella common, and high concentrations of pollution, there are serious hidden dangers of Legionella pneumonia in the hospital or even an outbreak occurs, it is recommended that the hospital water supply system of Legionella pollution and hospital-acquired Legionella bacteria disease monitoring water systems and study the feasibility of an effective method for removal of Legionella contamination. Objective: To separate water supply system of five hospitals in Shanghai 25 Legionella pneumophila serotype 1 (LP1) genotyping understand the LP1 gene polymorphism in a Shanghai hospital environment analysis between hospitals LP1 Genotyping ties and differences, and to compare the results of the three kinds of genotyping methods. Method: the application of pulsed-field gel electrophoresis (PFGE), gene sequencing typing (SBT) and repetitive sequence polymerase chain reaction (Rep-PCR) technology will be a total of 25 LP1 genotyping separation of five hospitals. PFGE and Rep-PCR results expressed mutual contact with tree clustering Figure SBT results are uploaded to the site to obtain the corresponding strain typing Model Model strain typing linkages. Results: PFGE typing 24 LP1 (1 strain typing) is divided into subtypes of type 10, where the epidemic strains of type A, B, E of 3. SBT typing of 25 isolates were divided into seven types, most of ST-1 and ST-780. ST-780 and ST-784 are Chinese mainland unique strain type. 2 LP1 asd sequence failed all sequence matching website not get ST. Rep-PCR typing 23 LP1 divided into A, B, C, D four regional similarity is greater than 98.6% of the strains belonging to the same type of Legionella in each district, two unclassified. A District 11 LP1, respectively, from the hospital 1,2,6, is divided into seven different types of similarity of 98.6%, while Area B strains are mainly derived from the hospital 5, similarity and strip analysis is divided into 4 type. The three kinds Genotyping show that the presence of the same genotype, the major epidemic strain LP1 and dissemination of strains between different hospitals in Shanghai hospital water supply system memory and the memory in different genotypes of the same hospital. Fractal method the SBT and Rep-PCR Processed shortest three kinds of genes, the operation is relatively simple, and reliable SBT parting the results obtained, does not depend on the judgment of the graphics, sub-type high accuracy and is easy to different laboratories The comparison between expensive. PFGE strains higher resolution SBT the carve-type consistent strains in PFGE can be divided into different subtypes, but time consuming, complicated operation, rely on competent judgment and understanding of the image, resulting in various laboratories between the comparison difficult. Conclusion: Shanghai hospital water systems LP1 presence of epidemic strains and sporadic strains exist between different hospitals of the same genotype and memory in different genotypes of the same hospital. Serum during epidemiological investigations can not simply rely on LP1 monoclonal antibody typing make epidemiological association must correlation analysis by means of molecular biological methods. SBT typing accuracy rate, contribute to the comparison between the various laboratories, PFGE strains with higher resolution, but the need for gel image interpretation, is not conducive to the comparison.

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CLC: > Medicine, health > Basic Medical > Medical Microbiology ( pathogenic bacteriology,pathogenic microbiology ) > Pathogenic bacteria
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