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A 56-year-old Japanese male was admitted to Toyohashi Municipal Hospital because of fever, cough, and dyspnea. Chest X-ray film showed bilateral alveolar infiltrates. He suffered from severe hypoxemia and was given a diagnosis of acute respiratory distress syndrome. He was also complicated with disseminated intravascular coagulation and pseudomembranous colitis. He fully recovered by intensive treatment with antibiotics, mechanical ventilation and endotoxin eliminating therapy. Legionella longbeachae was isolated from his respiratory specimens and was regarded as the etiologic agent of his pneumonia.

Microbiological contamination of hot spring bath water is a public health concern. A province-wide survey was carried out to determine the extent and distribution of both Legionella and free-living amoebae contamination. Among 30 samples of hot spring bath from 12 sites in Kanagawa, Japan, L. pneumophila was detected in 21 water samples from 11 sites, ranging from 10(1)-10(3) CFU/100 ml. Serogroups 3, 5 and 6 of L. pneumophila were predominantly isolated from the samples. Naegleria (46.7%), Platyamoeba (33.3%), Acanthamoeba (10.0%) and 2 other genera of free-living amoebae were detected in 22 samples from 11 sites. One or more genera of host amoebae of Legionella occurred in 17 samples (56.7%) from 9 sites. Another thing to be noted is that 13 water samples contained N. lovaniensis. Although N. lovaniensis is nonpathogenic, it is considered an indicator organism for places that are suitable for the growth of N. fowleri, a causative agent of primary amoebic meningoencephalitis in man.

In order to promote the serological diagnosis of legionellosis in the clinical laboratory, the cutoff values of serum anti-Legionella antibody titers for microplate agglutination (MPAT) test were determined. Antibody levels were tested for 178 serum specimens including 98 healthy persons, 22 ordinally workers having either metabolic or renal failure, definitely diagnosed patients of 17 mycoplasmal and 9 chlamydial pneumonia, 32 patients of other bacterial pneumonia. Heat killed unstained cell suspension of each strain of Legionella pneumophila serogroup (SG) 1a, 1b, SGs 2 to 6, L. bozemanii, L. dumoffii, L. gormanii, and L. micdadei were used as antigens. Strains of L. pneumophila SG 1b were mainly isolated from environmental specimens. However, in some Legionella pneumonia cases, etiologic agents were determined as L. pneumophila SG 1 b. Thus the representative strain of SG 1b was used as an antigen for the determination of the patient's antibody titer. Quantitative agglutination was performed by using a 96-well U-bottom microplate for each antigen. Test sera were diluted from 1:16 to 1:256. Results were read after 20 h at 25 degrees C. Cutoff values for 11 antigens were determined, at this moment, as 4-fold or greater increase in level to > or = 1:128 in paired sera, and > or = 1:256 in single serum. However, final diagnosis should be given by over-all coordination of serological results and clinical symptoms together with other laboratory findings. Two culture-positive Legionella pneumonia cases due to either SG3 or 6 in which significant rise of serum antibody titers against organisms of corresponding SG estimated by MPAT method were discussed.

Legionellae was found in 57 per cent of 94 cooling towers and 21.8 per cent of 78 other environmental sources. These figures reveal that the existence of legionellae in cooling towers is more prevalent than that found in other environmental sources. Legionella pneumophila serogroup 1 was the most prevalent organism among the legionellae found in cooling towers and other environmental sources. The recovery of legionellae in each province was seasonally independent and was found throughout the year. This is the first report of an environmental survey representing the existence of legionellae in every region of Thailand.

We analyzed the initial and follow-up chest radiographs of 28 patients with culture-positive Legionella pneumonia, and developed a scoring system to quantitate the severity of radiological findings for pneumonia. Intrapulmonary shadows were observed on the initial chest radiograph in 26 patients, but pleural effusion was noted in only one. In one patient the initial chest radiograph had probably been obtained too early to reveal any pulmonary change. Alveolar shadows were noted on the initial radiograph in 21 (81%) patients, and interstitial shadows in 5 (19%). In ten (38%) patients shadows were present in both lung fields. Shadows were prominent in the middle and lower lung fields. A cavity was noted in only one patient, and pleural effusion was also noted at some time during the clinical course in 19 (70%). A large amount of pleural effusion was observed in four patients. The average pneumonia severity score was 3.3 in the 9 patients who survived, and 5.1 in the 17 who died (p > 0.05). The mortality rate was 53% in the 17 patients with pneumonia severity score of 5 or less and 89% in the 9 patients with a score of 6 or more (p > 0.05). Twelve patients died within one week after the initial chest radiograph was obtained. There were no differences among patients with community-acquired infection with or without underlying disease and those with nosocomial infection in characteristic and extension of shadow, presence of pleural effusion, or pneumonia score. The chest radiograph of Legionella pneumonia include bilateral shadow findings characteristic, pleural effusion and rapid progression of shadow, and are clinically useful for diagnosis.

The effects of biocidal treatments for cooling towers were examined through the use of chemicals and ultraviolet irradiation to inhibit the growth of legionellae and other microorganisms. In the water of cooling towers without continuous biocidal treatments, heterotrophic bacteria and bacterivorous protozoan first appeared, and then legionellae increased up to 10(4) CFU/100 ml. When a UV sterilizer was connected to the cooling tower, the legionellae count was 1/10 or 1/100 of that in the nontreated tower water. In the water of towers supplemented continuously with the biocidal chemicals, legionellae were not found during a 4-month period. The biocidal treatments tested were proved to suppress the increase of legionellae in cooling-tower water, and thus are useful in preventing the outbreak of legionellosis due to inhalation of contaminated aerosol from the cooling tower system.

In view of the wide-spread existence of legionellae in cooling-tower and other environmental water, asymptomatic infection of this organism could occur. In order to verify the possibility of colonization of legionellae at lower respiratory tract of patients with various pulmonary diseases, a total of 22,036 sputum samples from in- and out-patients at National Sanyoso Hospital were examined during a five-year period from September, 1984 to August, 1989. Four (0.073%) out of 5,502 cases were culture-positive for L. pneumophila. L. pneumophila strains were isolated from expectorated, subsequently washed sputum samples of two male and two female patients with respiratory tract diseases. The identification of the isolates was genetically confirmed by the fluorometric microplate DNA-DNA hybridization method. The serogroup (SG) and viable counts of L. pneumophila per ml of sputum of each patient were as follows: 73 y/o female K.H., SG-6, 10(3) CFU; 75 y/o male H.J., SG-5, 10(4) CFU; 61 y/o female M.S., SG-5, 10(5) CFU; and 77 y/o male M.G., not-agglutinable against SG-1-6 antisera, 10(4) CFU. None of the four patients was clinically suspected of legionellosis and antibody titer of paired sera remained 1:64 or lower than 1:32. From these findings, we concluded that L. pneumophila can cause, though quite rarely, asymptomatic infection in human respiratory tract. None of the environmental samples obtained from in- and out-side of the Hospital was culture-positive for legionellae. Thus, the source of infection has remained unknown.

Rapid genetic identification of 23 Legionella species was performed using microdilution plate hybridization. When an isolate appeared to be a strain of the Legionella species, its DNA was quickly extracted, labelled with photobiotin and distributed to microdilution wells where 23 different DNAs had previously been immobilized. After hybridization for 90 min at 45 degrees C, the microdilution well which emitted the maximum fluorescence was determined. The criterion for interpreting results of this genetic identification method is given.

Legionella pneumophila in sterile distilled water was not detected after ultraviolet irradiation by FLONLIZER, a new-type sterilizer, at a flow rate of 82.5 to 364.8 liters/hr. When irradiated by FLONLIZER at a flow rate of under 324.0 liters/hr, no viable cells of legionellae, other heterotrophic bacteria and bacterivorous protozoa were detected in the cooling tower water, which was found to contain L. pneumophila. No viable cells of L. pneumophila and L. bozemanii suspended in sterile distilled water were detected after the irradiation with UV-doses of over 6.16 X 10(3) micro W.sec/cm2. At the irradiation of low UV-doses under 1.06 X 10(4) micro W.sec/cm2, the viable count of legionellae recuperated by photoreactivation from UV-damage increased with the exposure time under a white fluorescent lamp. However, in the samples irradiated with UV-doses of over 3.52 X 10(4) micro W.sec/cm2, equal to the FLONLIZER, legionellae did not recuperate even after 18 hr illumination with a white fluorescent lamp. FLONLIZER is thus expected to act as a sterilizer which can control the legionellae inhabiting cooling tower systems placed in outdoor space.

The occurrence and viable counts of Legionella pneumophila in acid-treated water samples of 62 cooling towers on the main island of Japan were determined by inoculating them onto plates of Wadowsky-Yee-Okuda (WYO) agar medium. WYO plate cultures of 39 (63%) of the samples yielded L. pneumophila with viable counts ranging from 10 to 10(4) colony-forming units per 100 ml. Of the L. pneumophila isolates, 157 were serologically identified as serogroup 1, and the remaining 21 were agglutinated by serogroup 3 (2 strains) and serogroup 6 (19 strains) antisera. In each culture-positive water sample, the pH and the number of other bacteria were found not be statistically significantly correlated with the viable counts of L. pneumophila. However, a higher rate of recovery of L. pneumophila was obtained with the water samples with a smaller number of other bacteria. Practical use of commercially available antialgal or antimicrobial agents was found not to be significantly effective for controlling the occurrence and growth of L. pneumophila in cooling tower water.