Detection of Legionella DNA in guinea pig peripheral leukocytes, urine and plasma by the polymerase chain reaction

Legionella DNA has been detected in respiratory tract, serum and urine samples from patients with pneumonia by the polymerase chain reaction. A guinea pig model was used to assess whether Legionella DNA could also be detected in peripheral leukocytes during active infection. Ten guinea pigs were infected intraperitoneally with Legionella pneumophila serogroup 1, and leukocyte, plasma and urine samples were collected immediately before inoculation and on days 1, 3, 7 and 14 thereafter. All samples were tested for Legionella DNA by the polymerase chain reaction. Overall, Legionella DNA was detected in 55% of leukocyte samples, 28% of urine samples and 21% of plasma samples collected after inoculation. The sensitivity of the polymerase chain reaction on leukocytes was highest for samples collected within 3 days of inoculation. Further studies testing leukocyte samples from human Legionella infection are required to confirm these observations.

Remission of hairy cell leukemia without treatment

A patient is described with hairy cell leukemia, in whom a remission occurred spontaneously or in association with Legionnaires or subsequent HIV infection. Possible pathophysiological mechanisms are reviewed. Currently it is seventeen years since the diagnosis of hairy cell leukemia and fourteen years since the infusion of HIV infected blood. Hairy cell leukemia has yet to return and HIV infection has not progressed to AIDS.

IL-10 enhances the growth of Legionella pneumophila in human mononuclear phagocytes and reverses the protective effect of IFN-gamma: differential responses of blood monocytes and alveolar macrophages

Legionella pneumophila is a facultative intracellular pathogen that parasitizes human alveolar macrophages and blood monocytes recruited to the lungs. The inhibitory cytokines IL-10, TGF-beta, and IL-4 generally deactivate macrophages and permit enhanced microbial growth in some models of intracellular infection, but their effects on human alveolar macrophages are unknown. We hypothesized that inhibitory cytokines could facilitate the infection of human alveolar macrophages and monocytes by virulent intracellular lung pathogens. Therefore, we tested the effects of IL-10, TGF-beta, and IL-4 in an in vitro model of human alveolar macrophage and monocyte infection with L. pneumophila. We found that unstimulated alveolar macrophages supported over 100-fold greater L. pneumophila growth than did unstimulated monocytes. IL-10 treatment significantly enhanced L. pneumophila growth in monocytes, and completely reversed the protective effect of IFN-gamma against intracellular L. pneumophila replication. IL-10 had similar but less potent effects on alveolar macrophages. In contrast, TGF-beta and IL-4 had no significant effects on L. pneumophila growth in resting or IFN-gamma-activated monocytes or alveolar macrophages. IL-10 blocked TNF-alpha production by infected cells, but exogenous TNF-alpha did not reverse the activating defect in cells cocultured with IFN-gamma and IL-10. Finally, L. pneumophila-infected monocytes produced substantially more IL-10 than did infected alveolar macrophages. In summary, IL-10 significantly enhances the growth of L. pneumophila in human monocytes, reverses the protective effect of IFN-gamma, blocks TNF-alpha secretion, and is secreted by infected monocytes and alveolar macrophages. Induction of IL-10 may be a virulence mechanism that promotes intracellular bacterial replication in human legionellosis.

Use of the polymerase chain reaction to detect Legionella DNA in urine and serum samples from patients with pneumonia

Legionella pneumonia can be difficult to diagnose. Existing laboratory tests for detecting Legionella species lack sensitivity or provide only a retrospective diagnosis. We used the polymerase chain reaction (PCR) with primers that amplify a 104-base pair segment of the coding region of the 5S tRNA gene to detect Legionella DNA in urine and serum samples from patients with pneumonia. Stored urine and serum samples from patients enrolled in two prospective studies of pneumonia were tested. Legionella DNA was detected in urine and/or serum samples from 18 (64%) of 28 patients with legionella pneumonia diagnosed by conventional tests, but it was not detected in urine or serum samples from 24 patients with pneumonia due to other organisms. The sensitivity of PCR improved to 73% if testing was restricted to samples taken within 4 days of the onset of symptoms. Detection of Legionella DNA in urine and serum promises to be a valuable tool for the rapid diagnosis of legionella pneumonia.

Increased plasma adenosine deaminase activity in the early phase of Legionella pneumophila infection in guinea pigs

We measured adenosine deaminase (ADA) activity in a guinea pig model of Legionella pneumophila infection. Female Hartley guinea pigs were inoculated intraperitoneally with one-quarter of the LD50 dose of L. pneumophila Philadelphia-1 strain. Control groups were inoculated with clinical isolates of Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae or Klebsiella pneumoniae. Each group consisted of 5 animals. ADA activity in plasma was assayed calorimetrically before and at various intervals after infection by measuring the amount of ammonia produced after adenosine was added to plasma samples. ADA activity before inoculation was 25.6 +/- 6.0 IU/1, it reached 174.4 +/- 60.0 IU/1 on day 3 after inoculation of L. pneumophila. ADA activity returned to normal levels on day 14. ADA activity did not increase significantly in guinea pigs infected with the other types of bacteria. These findings suggest that measurement of plasma ADA activity may be useful for the diagnosis of Legionella infection.

[Epidemiologic outbreak of Legionnaire's disease in an open community: 10 years later]

AIM

The aim of this study was to describe an outbreak of pneumonia due to L. pneumophila in Llutxent (Valencia) and to know the evolution of these patients 10 years after.

METHODS

The definition and identification of cases was carried out with the use of IFI techniques. An environmental and epidemiological study was performed for determining the origin and route of disease dissemination. The patients were clinically, functionally and serologically reviewed 10 years after.

RESULTS

From July to August 1983, 35 cases of pneumonia were reported in Llutxent (rate = 1.5%). L. pneumophila serotype 1 was serologically identified and was also found in shower heads and toilet tanks (in the context of the entry of sand into the drinking water supply). Ten years after, the patients had no respiratory symptoms with titers of antibodies versus Legionella sp. being under 1/64.

CONCLUSIONS

The authors emphasize the involvement of the distribution system for drinking water to the population in this first outbreak of Legionnaires disease in an open community. The health care measures taken were effective as demonstrated by no further pneumonias being recorded and after normalization of the rate of antibodies on a 10 year review.

Myocarditis: a rare complication during Legionella infection

Legionella often causes systemic manifestations. The clinical spectrum now includes cardiac legionellosis. The first case of myocarditis was reported by Gross in 1981. To date few additional cases have been described. Myocardial involvement might be more frequent than supposed in legionnaires' disease.

[Comparative study of Legionella pneumonia and other nosocomial-acquired pneumonia]

We studied 20 cases of legionella pneumonia and 23 cases of non-legionella pneumonia. Hyponatremia, elevated GOT and GPT were higher (P < 0.05) in legionella pneumonia group. In spite of the number of cases with diarrhoea, dyspnea, nervous symptoms, myalgia and complication were higher, especially with diarrhoea in legionella pneumonia group when compared to non-legionella pneumonia group, but the number of cases in both types of pneumonia did not show a statistically significant difference.

A framework for investigating geographical variation in diseases, based on a study of Legionnaires' disease

Demonstration of geographical variations in disease can yield powerful insight into the disease pathway, particularly for environmentally acquired conditions, but only if the many problems of data interpretation can be solved. This paper presents the framework, methods and principles guiding a study of the geographical epidemiology of Legionnaires' Disease in Scotland. A case-list was constructed and disease incidence rates were calculated by geographical area; these showed variation. Five categories of explanation for the variation were identified: short-term fluctuations of incidence in time masquerading as differences by place; artefact; and differences in host-susceptibility, agent virulence, or environment. The methods used to study these explanations, excepting agent virulence, are described, with an emphasis on the use of previously existing data to test hypotheses. Examples include the use of mortality, census and hospital morbidity data to assess the artefact and host-susceptibility explanations; and the use of ratios of serology tests to disease to examine the differential testing hypothesis. The reasoning and process by which the environmental focus of the study was narrowed and the technique for relating the geographical pattern of disease to the putative source are outlined. This framework allows the researcher to plan for the parallel collection of the data necessary both to demonstrate geographical variation and to point to the likely explanation.

[The clinical picture of legionnaires' disease]

The results of the clinico-laboratory study of 12 cases of acute pneumonia of Legionella etiology are presented. The laboratory diagnosis of Legionella infection was carried out by the study of paired sera in the passive hemagglutination test with the use of Legionella pneumophila (serotype 1) erythrocyte diagnosticum. The clinical picture of pneumonia was characterized by a severe and moderate course of the disease. Characteristic symptoms indicating the presence of indurations and infiltrations in the lung tissue were registered. Roentgenological examination revealed that the foci of pulmonary tissue infiltration appeared in the segments of the lower lobes of both lungs. In 6 patients neutrophil leukopenia, in 4 patients relative lymphocytopenia, in 5 patients monocytopenia, in 11 patients the increase of the erythrocyte sedimentation rate and in 4 patients normochromic anemia were registered. More seldom changes in the levels of residual nitrogen, urea, fibrinogen and transaminases were observed. In most cases the resolution of pneumonia was observed on weeks 2-3 of treatment. In this treatment erythromycin, rifampicin and oleandomycin, used in combination, used in combination with detoxication and infusion therapy, vitamins, vascular and other symptomatic remedies, proved to be most effective. The cases of Legionella infection under study were sporadic and epidemiologically unrelated. The severity of the course of the disease depended mainly on the general state of the patient prior to infection, age and concomitant diseases.

Cytomegalovirus and legionella species as the cause of liver enzyme elevations in haemodialysis patients

We conclude that reinfection or recurrent infection with CMV or legionella may be responsible for serum glutamic-pyruvic transaminase (SGPT) elevations in up to one fourth of haemodialysis patients. Since NANB infection or asymptomatic coinfection with these agents cannot be discounted with certainty, it seems prudent to maintain haemodialysis patients with abnormal liver-function tests on Body Fluid Precautions, even if they remain asymptomatic.

[Adult respiratory distress syndrome in legionella pneumonia--successful treatment with extracorporeal CO2 elimination procedures]

We report on successful treatment of an 46-year-old patient with ARDS (Adult Respiratory Distress Syndrome), caused by legionella-pneumophilia-pneumonia. The treatment with conventional artifical mechanical ventilation had failed. The new method of extracorporeal CO2-Elimination and low frequency positive pressure ventilation (ECCO2-R-LFPPV), introduced by L. Gattinoni (2) was in that case of severest ARDS very helpful. Supported by antimicrobial therapy with Erythromycin and Rifampicin the lung function could be improved to "restitutio ad integrum". Changes in chest radiographs, clinical parameters of ventilation, gas exchange and haemodynamics as well as the results of sequential pulmonary studies are demonstrated and discussed.

Characteristics of anti-Legionella antibodies in patients infected with Legionella pneumophila serogroups 1, 6, and 10

Nosocomial infections with Legionella pneumophila serogroups 1 and 10 in the Leiden University Hospital and infections with L. pneumophila serogroup 6 in neighboring hospitals gave us an opportunity to study the development of opsonizing antibodies against L. pneumophila serogroups 1, 6, and 10 in the serum of 13 patients. Seven of these patients were infected with L. pneumophila serogroup 1, two were infected with serogroup 6, and four were infected with serogroup 10. The opsonic cross-reactivity of antibodies against these serogroups of L. pneumophila and complement involvement in opsonization were also investigated. Convalescent-phase sera from patients infected with L. pneumophila serogroup 1 or 6 were able to promote ingestion of these serogroups by polymorphonuclear leukocytes, whereas ingestion of L. pneumophila serogroup 10 was enhanced only in the presence of convalescent-phase sera from patients infected with this serogroup. Opsonization of L. pneumophila serogroups 1, 6, and 10 was complement dependent.

Are health care workers at risk for infection during an outbreak of nosocomial Legionnaires' disease?

We studied data from 500 health care workers to answer the question: Are health care workers at risk for infection during an outbreak of nosocomial Legionnaires' disease? These workers were employed at a hospital where eight cases of nosocomial Legionella pneumophila serogroup 1 pneumonia occurred over a 4-week period. The source was potable water. Acute-phase blood samples were collected on the day the water supply was decontaminated, convalescent samples were collected 4 to 6 weeks later from 373 subjects, and a single serum sample was obtained from an additional 127 subjects. Antibody titers to L. pneumophila were determined by an indirect immunofluorescent antibody (IFA) technique and by a microagglutination assay with the epidemic strain as the test antigen. Subjects who had an IFA titer of greater than or equal to 1:256 were retested with an anti-human IgM conjugate. None of the 373 health care workers had a fourfold rise in antibody titer. The geometric mean antibody titer of 73.8 for the 500 health care workers was significantly higher than that of 68.1 for 976 blood donors (p less than 0.01). Only 2.4% had recent infection as evidenced by a microagglutination test, despite the fact that 84% were susceptible. We conclude that in the setting of a short-term outbreak of Legionnaires' disease caused by contaminated potable water the risk of infection among health care workers is low: 2.4% or less.

Clinical chemical responses to experimental airborne legionellosis in the guinea-pig

Legionella pneumophila infection of guinea-pigs by the aerosol route with either of two strains, one (serogroup I) giving an acute the other (serogroup 3) giving a protracted illness, induced a pyrexia and similar pneumonic lesions. With both strains there was a bacteraemia with early decreases in serum iron and zinc and increases in serum copper concentrations. Marked changes in other serum components were evident only in those animals which had protracted illness (serogroup 3-infected animals). These included transient increases in aminotransferase, creatine kinase and sorbitol dehydrogenase activities and triglyceride levels, together with gradual decreases in alkaline phosphatase and leucine aminopeptidase activities. Serum lysozyme activity and acute-phase protein synthesis increased, as did the ratio of phenylalanine to tyrosine. The findings confirm the relevance of the aerosol-infected guinea-pig model for the investigation of the disease processes and evaluation of therapeutic measures for use in man.

Changes in iron and transferrin levels and body temperature in experimental airborne legionellosis

Guinea pigs were infected with either 5 or 100 cfu of Legionella pneumophila by aerosol exposure. Between two and 10 days after infection, groups of animals were killed, and their lungs and spleen were removed and cultured quantitatively. L. pneumophila multiplied in the lungs and spread to the spleen; the organisms were cleared first from the spleen and then the lungs. Significant changes were demonstrated in serum iron and transferrin levels and body temperature. The body temperature correlated directly and the serum iron concentration correlated inversely with the number of L. pneumophila recovered from the lungs but not from the spleen. These data suggest that fever and iron may restrict the growth of L. pneumophila in vivo.

Myelosuppression in Legionnaires' disease

A patient undergoing examination for moderately severe renal insufficiency had fulminant five-lobed pneumonia caused by Legionella pneumophila. Her clinical course was complicated by granulocytopenia. Bone marrow aspiration showed notable inhibition of myelopoiesis, involving all stages of maturation. The presence of a serum inhibitor of granulopoiesis was demonstrated by in vitro bone marrow culture. Normal bone marrow cultured in the presence of serum from two normal control subjects yielded 69 +/- 5.2 (mean +/- SE) and 61 +/- 5 granulocyte colonies. When the patient's serum was substituted for normal human serum only 14.3 +/- 2.3 colonies were formed. Each of the drugs to which she had been exposed was tested in the in vitro system, using therapeutic concentrations, and none showed significant suppression of granulocyte colony formation. These observations indicate that legionnaires' disease was associated with a serum factor that notably inhibited the growth of granulocyte colonies in this patient.

Legionnaires' disease with severe hypoxemia and saddleback fever

In the case of Legionnaires' disease described, severe respiratory problems necessitated mechanical ventilatory support, tracheal intubation, and positive end-expiratory pressure. Fever was eliminated with erythromycin therapy but returned after five days, and lung infiltrates spread. After supplementary treatment with other antibiotics and methylprednisolone sodium succinate, both the fever and the infiltrates disappeared. We feel that the multisystem involvement and the recrudescence of fever in our patient emphasize the wide spectrum of characteristics of Legionnaires' disease and the importance of continuation of antibiotics for a prolonged period to eradicate infection.

Legionnaires' disease: concentrations of selenium and other elements

Selenium concentrations in the serums of 17 acutely ill Legionnaires' disease patients were significantly lower than in their matching convalescent-phase serums. This trend was not observed in ten similarly paired samples of serum from control patients with pneumonia. There were no significant differences in the concentrations of nickel, copper, bromine, rubidium, lead, barium, or titanium in the serums of Legionnaires' disease and control patients.