Evaluation of a rapid screening assay for bacterial identification (Dot-ELISA) in fecal samples from children

With the objective of standardizing a Dot Enzyme-Linked Immunosorbent Assay (Dot-ELISA) to detect antigens of fecal bacterial enteropathogens, 250 children, aged under 36 months and of both sexes, were studied; of which 162 had acute gastroenteritis. The efficacy of a rapid screening assay for bacterial enteropathogens (enteropathogenic Escherichia coli "EPEC", enteroinvasive Escherichia coli "EIEC", Salmonella spp. and Shigella spp.) was evaluated. The fecal samples were also submitted to a traditional method of stool culture for comparison. The concordance index between the two techniques, calculated using the Kappa (k) index for the above mentioned bacterial strains was 0.8859, 0.9055, 0.7932 and 0.7829 respectively. These values express an almost perfect degree of concordance for the first two and substantial concordance for the latter two, thus enabling this technique to be applied in the early diagnosis of diarrhea in infants. With a view to increasing the sensitivity and specificity of this immunological test, a study was made of the antigenic preparations obtained from two types of treatment: 1) deproteinization by heating; 2) precipitation and concentration of the lipopolysaccharide antigen (LPS) using an ethanol-acetone solution, which was then heated in the presence of sodium EDTA.

Legionnaires' disease in the renal transplant unit of "Hospital das Clinicas, FMUSP". During a five year period (1988-1993)

Several reports have related Legionella pneumophila with pneumonia in renal transplant patients, however this association has not been systematically documented in Brazil. Therefore this paper reports the incidence, by serological assays, of Legionella pneumophila serogroup 1 in these patients during a five year period. For this purpose sera from blood samples of 70 hospitalized patients with pneumonia from the Renal Transplant Unit of Hospital das Clinicas, FMUSP collected at the acute and convalescent phase of infection were submitted to indirect immunofluorescence assay (IFA) to demonstrate anti-Legionella pneumophila serogroup 1 antibodies. Of these 70 patients studied during the period of 1988 to 1993, 18 (25.71%) had significant rises in specific antibody titers for Legionella pneumophila serogroup 1. Incidence was interrupted following Hospital water decontamination procedures, with recurrence of infections after treatment interruption. In this study, the high susceptibility (25.71%) of immunodepressed renal transplant patients to Legionella pneumophila serogroup 1 nosocomial infections is documented. The importance of the implementation and maintenance of water decontamination measures for prophylaxis of the infection is also clearly evident.

[Legionellosis associated with pneumopathies in São Paulo. Study of the etiologic confirmation by isolation and serology]

The role of Legionella sp as an important pathogen, although reported in many countries, had not been well documented in Brazil. The main objective of the present study is to detect this organism or it's immunological response in patients with pulmonary infections in the city of São Paulo. For this purpose, specific laboratory methodology was introduced to cultivate the agent and demonstrate specific antibodies by serology. Patients from two University centers in São Paulo were studied: 100 from the Hospital Universitario, University of São Paulo with general pulmonary infections and 100 from Hospital das Clínicas, Faculdade de Medicina, University of São Paulo. The latter were selected to exclude pulmonary infections of other bacterial aetiology, and 30 of these were selected from the Renal Transplant Unit. Clinical specimens for cultures included sputum tracheal secretion, pleural, fluid, bronchial washing or lung tissue biopsy. Isolation of Legionella sp was attempted in BCYE medium with and without antibiotics, presumptive diagnosis by biochemical methods and identification through direct immunofluorescence staining and slide agglutination test. Direct evidence of the organism in tissue was attempted by direct immunofluorescence staining. Specific antibodies for Legionella pneumophila serogroup 1 were tested by the indirect immunofluorescence assay. Serology was also carried out in specimens from human contacts with Legionnaires' Disease. Legionella pneumophila serogroup 1 was isolated from two patients, demonstrating the presence of the pathogen in this country. Serology was able to establish present or past infection with the agent in 16 of the 100 patients from Hospital das Clínicas and in only one from Hospital Universitário. In patients considered as high risk groups from Hospital das Clínicas with renal transplantation, serology for present or past Legionellosis was positive in 33% and in 8.5% for community acquired infections. Serology in specimens from Medical personnel in contact with patients of Legionnaires' disease was positive for past infection in one single subject, confirming information already published that direct transmission from person to person is unusual. The introduction of specific methods for laboratorial evidence of Legionella sp infections at the Hospital das Clínicas-Faculdade de Medicina USP community has permitted diagnosis in able time to allow use of specific anti-microbial therapy, with good results.

Five cases of nosocomial and community-acquired Legionnaires' disease in São Paulo, Brazil

Legionella sp has been emerging over the last decade as an important cause of pneumonia both hospital and community-acquired. Following an outbreak in a Renal-Transplant Unit stocked serum was tested for antibodies against Legionella pneumophila serogroup 1, and 5 cases of Legionnaires' Disease were reviewed. Two of the cases were nosocomial and three cases were community-acquired. Clinical and laboratorial aspects were similar to those expected for other causes of pneumonia, however jaundice was encountered in two cases. This study suggests that the real incidence of pneumonia caused by Legionella sp is being underestimated and the authors emphasize the importance of considering Legionnaires' Disease when empirically treating community-acquired pneumonia.

[Legionella pneumophila associated with acute respiratory insufficiency. 1st isolation in Brazil]

Isolation of Legionella pneumophila sero-group 1 with serological evidence of present infection is reported from a 40 year-old male with serious respiratory infection which developed into acute respiratory failure. It was characterized by severe hypoxemia resistant to high inspired oxygen concentrations and radiographically by diffuse infiltrates in both lungs suggesting the clinical aspect of ARDS. Following the introduction of clindamycin, amikacin, ceftriaxone, volume-cycled ventilator and positive end expiratory pressure (PEEP) of 14 cm H2O, stabilization of clinical conditions and gradual recovery were achieved. Suspecting of legionellosis, blood and tracheal secretions specimens were collected for specific laboratory research. From tracheal secretion cultivated in BCYE medium, gran-negative bacilli were isolated and identified as Legionella pneumophila serogroup 1 through cultural and biochemical characteristics and direct immunofluorescence and slide agglutination tests. Serology (IFA) with blood samples collecting during the 1st, 3rd, 4th and 6th weeks of illness demonstrated antibody titers to the isolated microorganism of 128, 1024, 4096 and 8192, respectively. Definitive results were obtained during the patient's recovery. The authors emphasize: a) the demonstration of the presence of Legionella sp. as a pathogenic agent in Brazil; b) the importance of supportive care in the clinical outcome; c) the need of remembering this pathogen while making differential diagnosis of pneumonias and of continuing to pursue this etiology with specific laboratory methodology.