Isolation of Pittsburgh pneumonia agent from a hospital shower.

Tatlockia (Legionella) micdadei, the Pittsburgh pneumonia agent, was isolated from a hospital shower. Although it was not possible, at the current time, to establish an epidemiological link to disease acquisition, this information may be significant because it provides further evidence that a water-associated reservoir of this organism exists within the hospital.     

Tatlockia micdadei (Pittsburgh pneumonia agent) growth kinetics may explain its infrequent isolation from water and the low prevalence of Pittsburgh pneumonia.

Sediment and indigenous microflora taken from water distribution systems has been shown to promote the survival of Legionella pneumophila. The effect of sediment and indigenous microflora on Tatlockia micdadei (Pittsburgh pneumonia agent, PPA) was evaluated by growth curve experiments. Symbiosis between PPA and environmental bacteria was demonstrated by satellitism experiments. Unlike L. pneumophila, the concentration of PPA remained stationary in test tube suspensions containing both microflora and sediment. The difference in the ecology between the two organisms may explain the infrequent environmental recovery of PPA and, ultimately, the epidemiologic differences between Legionnaires disease and Pittsburgh pneumonia.     

Tatlockia micdadei (Pittsburgh pneumonia agent) growth kinetics may explain its infrequent isolation from water and the low prevalence of Pittsburgh pneumonia

Sediment and indigenous microflora taken from water distribution systems has been shown to promote the survival of Legionella pneumophila. The effect of sediment and indigenous microflora on Tatlockia micdadei (Pittsburgh pneumonia agent, PPA) was evaluated by growth curve experiments. Symbiosis between PPA and environmental bacteria was demonstrated by satellitism experiments. Unlike L. pneumophila, the concentration of PPA remained stationary in test tube suspensions containing both microflora and sediment. The difference in the ecology between the two organisms may explain the infrequent environmental recovery of PPA and, ultimately, the epidemiologic differences between Legionnaires disease and Pittsburgh pneumonia.     

Alveolar macrophage activation in experimental legionellosis.

Legionella pneumophila is a facultative intracellular parasite of alveolar macrophages. In vitro studies have shown that lymphokine-activated mononuclear phagocytes inhibit intracellular replication of L. pneumophila. To determine if recovery from legionellosis is associated with activation of alveolar macrophages in vivo to resist L. pneumophila, we studied an animal model of Legionnaires' disease. Rats were exposed to aerosolized L. pneumophila and alveolar macrophages were harvested during the recovery phase of infection. We compared these alveolar exudate macrophages with normal resident alveolar macrophages for the capacity to support or inhibit the intracellular growth of L. pneumophila. We also measured Ia expression as a marker of immunologic activation, and studied binding of bacteria, superoxide release, and the expression of transferrin receptors as potential mechanisms of resistance to L. pneumophila. For perspective on the specificity of these responses, we also studied alveolar exudate cells elicited by inhalation of heat-killed L. pneumophila, live Listeria monocytogenes, and live Escherichia coli. We found that alveolar exudate macrophages elicited by live L. pneumophila, but not heat-killed L. pneumophila, resisted the intracellular growth of L. pneumophila. Exudate macrophages in resolving legionellosis exhibited increased Ia expression, diminished superoxide production, and downregulation of transferrin receptors. Binding of L. pneumophila to exudate macrophages was indistinguishable from that to resident macrophages in the presence of normal serum, and augmented in the presence of immune serum. Alveolar exudate macrophages elicited by E. coli also inhibited growth of L. pneumophila, and exhibited a modest increase in Ia expression without change in transferrin receptors. Exudate cells induced by L. monocytogenes exhibited up-regulation of Ia without diminution of superoxide release. Alveolar cells harvested after inhalation of heat-killed L. pneumophila did not differ from resident alveolar macrophages in the expression of surface markers. These findings suggest that alveolar macrophages are immunologically activated in vivo to serve as effector cells in resolving legionellosis, and that live bacteria are required to induce this expression of immunity. The mechanism of resistance to parasitism by L. pneumophila may entail restriction of the intracellular availability of iron, but does not involve diminished bacterial binding or an augmented respiratory burst.     

Cytokines and legionellosis

Recent studies have led to an enhanced understanding of the role of cell-mediated immunity and cytokines in Legionnaires' disease. In particular, the effect of interferon gamma on human mononuclear phagocyte iron metabolism and the role of iron availability inLegionella pneumophila intracellular multiplication in human monocytes has been elucidated. With this knowledge it is now possible to develop treatment strategies for Legionnaires' disease using interferon gamma and/or agents affecting human mononuclear phagocyte iron metabolism.Abbreviations M-CSF Macrophage colony stimulating factor     

Malaria in Nottingham children.

In five and a half years 16 children were admitted to hospital in Nottingham suffering from malaria. Thirteen cases were caused by Plasmodium vivax and two by P falciparum, and in one the type was not identified. All were children of immigrant parents, predominantly from Pakistan, although most were born in England but had been visiting Asia. Three children were ill on or soon after arrival, but in the others the onset of symptoms was delayed by up to nine months. All made an uneventful recovery, although two children with P vivax infections had a further relapse after chloroquine treatment only. The question "Where have you been?" should be put to all immigrant parents whose children have a febrile illness. Agencies who provide travel for Asian immigrant families returning home for a visit should be encouraged to provide instructions about malaria prophylaxis.     

Standards for laboratory diagnostics of legionellosis and their application during epidemic outbreak of pneumonia in town Verkhnyaya Pyshma

High effectiveness of application of international standards for legionellosis laboratory diagnostics was confirmed during investigation of pneumonia outbreak in town Verkhnyaya Pyshma. Use of immunochromatographic method and enzyme immunoassay for detection of Legionella antigen in urine of patients allows to confirm diagnosis of Legionella infection during several hours, promptly begin etiologic antibacterial treatment and reveal possible sources of infection in potentially dangerous environmental objects.     

Cases of legionellosis infection in Tbilisi

The epidemic outbreak of Legionella infection at two industrial enterprises during the period of July-August 1988 is described. The results of the epidemiological study, the clinical course and the serological diagnosis of the outbreak are presented. For the first time in the USSR a new form of the disease has been described at the territory of Georgia. This form, named Legionella fever, is manifested mainly by skin eruptions.     

Overview of diagnostic and detection methods for legionellosis and Legionella spp.

Since 1977, the diagnostic tools for Legionnaires' disease have been based on culture and serological investigations. Both methods require considerable time to produce results and have 'low' to 'reasonable' sensitivity. Since the introduction of urinary antigen tests in the mid 1990s, underdiagnosis has diminished and mortality has declined, thanks to early diagnosis. To obtain the most accurate diagnosis, culture, serological investigation, and urinary antigen testing should all be performed. In the last decade, advances in polymerase chain reaction technology allowed the development of assays detecting Legionella nucleic acids in clinical and environmental samples. Thus far, only widely varying results with relatively small series have been reported. Furthermore, these assays which are still labour intensive and complicated are not yet practicable for the average medical and/or environmental microbiological laboratory.     

Chronic renal failure in Nottingham and requirements for dialysis and transplantfacilities.

A retrospective study of uraemic patients covering 12 months of 1970 and a prospective survey covering six months in 1973-4 is reported for a population of almost 3/4million. The number of patients requiring regular dialysis treatment or transplantation or both is considered to be 45 per million of population under 65, 39 per million under 60, and 29 per million under 50 years of age.     

Non-fundholding in Nottingham: a vision of the future.

The 1991 health service reforms introduced the internal market and grave individual fundholding practices budgets with which they could attempt to secure preferential access to secondary health care for their patients. In the view of many doctors this undermined the principle of equity on which the NHS was founded. In Nottingham 200 non-fundholding general practitioners have joined together to act in liaison with their purchasing health authority. A committed representative group of general practitioners can collectively offer more time and knowledge to the contracting process while minimising the impact on clinical workload. As a large purchaser with low management costs the group has secured access to quality secondary care which is equitably available to all patients, preventing the development of a local two tier service. Nottingham''s non-fundholding model of commissioning is equitable and efficient.     

Fatal legionellosis in patients with malignant hematologic diseases

Pneumonia was present in 70/157 (44.6%) autopsied patients with malignant hematologic diseases. In 16/70 patients (22.9%), legionellae were found to be the causative agents by screening lung tissue specimens with the direct fluorescent antibody method. In 5/16 patients with Legionella pneumonia, in whom legionellosis had been suspected clinically, the diagnosis had already been established by serology, urinary Legionella antigen detection, and culture. These results provide evidence that legionellosis is an important pneumonia etiology in patients with malignant hematological diseases. Thus, Legionella diagnostics should be applied routinely, and antibiotics effective in the treatment of legionellosis should be added to the usual therapy in patients with etiologically unexplained pneumonias. In view of the common occurrence of relapses of Legionella pneumonia, antibiotic therapy should be continued for an extended period.