Water-based cooling towers and their water supply at two hospitals in Johor were surveyed for the presence Legionella pneumophila. L. pneumophila were grown from 19 (76%) out of 25 collected water samples. One hospital cooling tower was contaminated with L. pneumophila serogroup 1.
cooling ; Legionella pneumophila ; Hospitals ; L ; Need for isolation

BACKGROUND: It is important to define a source of infection when outbreak of Legionella infections has occurred. The performance of a molecular strain typing method was evaluated for environmental and clinical isolates of Legionella pneumophila. METHODS: Thirteen environmental strains, eleven clinical isolates and one type strain (ATCC 33152) of Legionella pneumophila were used for the analysis of pulsed field gel electrophoresis. RESULTS: All 25 strains were discriminated into 21 types. Two strains isolated from different locations in a same building showed different types. Each two, four, and two strains were shown as the same PFGE patterns. CONCLUSIONS: Even though PFGE typing of Legionella pneumophila is excellent for strain differentiation, the same pattern does not necessarily indicate the same source of isolates.
Busan* ; Electrophoresis, Gel, Pulsed-Field ; Korea* ; Legionella pneumophila ; Legionella* ; Water*

Objective: To analyze the pollution status and influencing factors of Legionella pneumophila in a secondary water supply facility in a city. Methods: From June to August 2020, a survey on the level of Legionella pneumophila in secondary water supply unit was carried out in a city in northern China, and 304 sets of secondary water supply facilities were included in the study. A total of 760 water samples were collected from the inlet and outlet water of the secondary water supply facilities and some water samples in the water tank were collected for the detection of Legionella pneumophila, standard plate-count bacteria and related physical and chemical indicators. Through questionnaire survey, the basic information of secondary water supply facilities and daily management of water quality were collected. Multivariate logistic regression model was used to analyze the influencing factors of Legionella pneumophila contamination. Results: Among 304 sets of secondary water supply facilities, most of them were located in residential buildings [57.24% (174/304)]. High and low water tank water supply, low water tank variable frequency conversion water supply and non-negative pressure water supply accounted for 26.6% (81/304), 36.8% (112/304) and 36.5% (111/304), respectively. About 25.7% of facilities (78/304) were positive for Legionella pneumophila. Among them, the positive rates of Legionella pneumophila in high and low water tank water supply, low water tank variable frequency conversion water supply and non-negative pressure water supply facilities were 38.3% (31/81), 29.5% (33/112) and 12.6% (14/111), respectively. The results of multivariate logistic regression model analysis showed that the disinfectant residue could reduce the risk of Legionella pneumophila contamination in water samples, and the OR (95%CI) value was 0.083 (0.022-0.317). The increase of the standard plate-count bacteria and conductivity might increase the risk of Legionella pneumophila contamination in water samples. The OR (95%CI) values were 3.160 (1.667-5.99) and 1.004 (1.001-1.006), respectively. Compared with the non-negative pressure water supply, the risk of Legionella pneumophila contamination of secondary water supply facilities was increased by water supply from high and low water tanks and variable frequency conversion water supply from low water tanks, with OR (95%CI) values of 4.296 (2.096-8.803) and 2.894 (1.449-5.782), respectively. Conclusion: The positive rate of Legionella pneumophila in secondary water supply in the study city is high. Disinfectant residue, conductivity and method of water supply are associated with the positive rate of Legionella pneumophila.
Humans ; Legionella ; Water Microbiology ; Water Supply ; Legionella pneumophila ; Reproduction ; Disinfectants

Legionella pneumophila are intracellular pathogens, associated with human disease, attributed to the presence and absence of certain virulent genes. In this study, virulent gene loci (lvh and rtxA regions) associated with human disease were determined. Thirty-three cooling tower water isolates, isolated between 2004 to 2006, were analyzed for the presence of these genes by PCR method. Results showed that 19 of 33 (57.5%) of the L. pneumophila serogroup 1 isolates have both the genes. Six (18.2%) of the isolates have only the lvh gene and 2 (6.1%) of the isolates have only the rtxA gene. However, both genes were absent in 6 (18.2%) of the L. pneumophila isolates. The result of our study provides some insight into the presence of the disease causing L. pneumophila serogroup 1 in the environment. Molecular epidemiological studies will provide better understanding of the prevalence of the disease in Malaysia.
L ; Malaysia ; Genes ; Legionella pneumophila serogroup 1 ; occurrence

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*

Twenty two strains of Legionella species isolated from Jejudo, Korea were identified by comparing the rpoB (300 bp), dotA (360 bp), and mip (396 bp) gene sequence analysis. Furthermore, their genotypes were determined by sequence analysis of rpoB/dotA subgroup typing, pulse-field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) patterns. Of the 22 isolates, 21 strains were identified as L. pneumophila and 1 strain was close to L. erythra (>95% similarity of rpoB and mip). Most of the L. pneumophila strains (90%) belonged to P-I of rpoB/dotA subgroup typing, one strain of each P-III and P-IV. L. pneumophila isolates were further grouped into 4 and 6 different PFGE (P1 to P4) and RAPD (R1 to R6) patterns, respectively. On the basis of these genotypes, which may be useful for future epidemiological studies, existence of diverse L. pneumophilla population in Jejudo, Korea were observed.
DNA ; Electrophoresis ; Epidemiologic Studies ; Genotype ; Korea ; Legionella ; Legionella pneumophila ; Molecular Biology ; Sequence Analysis ; Sprains and Strains

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*

To use in the identification of Legionella pneumophila isolates, one Legionella genus-specific, an two L. pneumophila species-specific monoclonal antibodies (MAbs) were produced. Reactivities of the MAbs with Legionella species and non-Legionella strains were tested by immunoblot. MAb 7D8-F1, MAb 7D8-A9, and MAb 1G12-C11 reacted only with protein. MAb 7D8-F1 recognized a genus-specific epitope in the protein ranged from 28 to 34 kDa in the tested 40 species with 61 serogroups. MAb 7D8-A9 and MAb 1G12-C11 reacted strongly with 49 kDa and 70 kDa protein from 18 L. pneumophila serogroups but did not react with 39 non-L. pneumophila species, respectively. In addtion, 17 non-Legionella strains, including Coxiella burnetii, Klebsiella pneumoniae, Mycoplasma pneumoniae, Pseudomonas areoginosa, Francisella tularensis, and Staphylococcus pneumoniae did not show cross-reacivities with the three MAbs. The MAbs reacted with 28 environmemtal isolates and three clinical isolates previously identified as L. pneumophila. When the immunoblot patterns were divided into four types (type I~IV) by using MAb 7D8-F1, all the 31 isolates belonged to the type II. These results indicate that the MAbs were highly specific to Legionella and can be used for the identification of L. pneumophila isolates on the genus and species levels.
Antibodies, Monoclonal* ; Coxiella burnetii ; Francisella tularensis ; Klebsiella pneumoniae ; Legionella pneumophila ; Legionella* ; Mycoplasma pneumoniae ; Pneumonia ; Pneumonia, Mycoplasma ; Pseudomonas ; Staphylococcus

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