No abstract available.
Legionella*

BACKGROUND: Hospitals present ideal locations for transmission of Legionnaires' disease, a pneumonia-like disease caused by Legionella spp. In these settings, hospitalized patients may be exposed to aerosols generated by cooling towers, respiratory therapy equipment, showers and faucets, that facilitate transmission of the bacterium.

OBJECTIVE: The study aimed to determine the presence of Legionella spp. in water samples taken from the cooling tower and water holding systems of a hospital in Metro Manila.

METHODS: A total of 12 water samples were collected: 6 samples from the cooling tower, 4 from two cisterns and 2 from the water tank. The samples were concentrated, acid-treated, gram-stained and cultured. Biochemical tests were done for identification of Legionella spp.

RESULTS:  Legionella spp. was detected in 2 (16.67%) out of 12 samples, both of them from the pre-condenser sampling site of the hospital's cooling tower.

CONCLUSION: The study documents the presence of Legionella spp. in the cooling tower, a potential source of infectious aerosols that can be disseminated in the hospital and affect hospitalized patients.

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

Serological investigation of antibodies to Legionella species in 1,802 sera collected in seoul was conducted with indirect fluorescent antibody assay (IFA). With an antibody titer of > or =1:128 to be positive, 17 (0.9%) of these sera were positive and 6 (35.3%) of positive sera showed cross-reactions between Legionella species. The number of sera with antibody titers of > or =1:128 to L. pneumophila serogroup 1, L. pneumophila serogroup 4, L. pneumophila serogroup 5, L. bozemanii, L. micdadei, L. anisa were 6 (35.3%), 3 (17.6%), 3 (17.6%), 2 (11.8%), 1 (5.9%), 2 (11.8%) respectively. Among 17 positive sera, 10 (58.8%) sera were from male and 7 (41.2%) from female. An average age of them was 68.9 (+/-15.3; 27~89). Except for one serum, 16 (94.1%) of positive sera were from those older than 50 years old. The result suggests that the aged over 50 years old should be more careful of Legionella infection.
Aged ; Antibodies ; Female ; Humans ; Korea ; Legionella ; Male

The principal mode of the transmission of Legionnaires disease is an inhalation of the cooling tower water droplets in which Legionellae exist. As a central cooling system is popularized in many public buildings and large buildings nowadays, the number of cooling towers in rapidly increasing. Therefore the possibility of an outbreak of Legionnaires disease is likely increased. To determine the presence of Legionella in cooling tower water as the first step for the prevention of Legionnaires disease, 48 samples of cooling tower water were taken from 24 buildings in Taegu city in July and September 1987. Three samples out of 24 water samples in September yielded Legionella but it was not isolated in the samples of July. Isolated 3 Legionellas were identified as Legionella peumophila. It seems that Legionella from the cooling tower will be isolated more frequently in late summer than early because central cooling system is stopped operation during winter season which in cool. As based on our survey, Legionnaires disease can occur in Taegu city and if it happens it is most likely due to L. pneumophila.
Daegu ; Inhalation ; Legionella* ; Legionnaires' Disease ; Seasons ; Water*

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

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: 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*

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