RESUMEN
INTRODUCTION: Community-acquired pneumonia (CAP) continues to be a leading cause of hospitalization and mortality worldwide. Streptococcus pneumoniae and Legionella pneumophila remain the major etiological agents and are responsible for a significant proportion of CAP mortality. Among diagnostic tests for CAP, urine antigen detection of S. pneumoniae and L. pneumophila is widely accepted due to the simplicity of collection and the rapidity of the test results. Areas covered: This comprehensive review outlines the urinary antigen tests available, discusses their sensitivity and specificity, and assesses the usefulness of their results as the basis for targeted therapy. Expert commentary: There have been advances in urine antigen detection tests for patients with CAP. New methodologies show greater sensitivity, detect S. pneumoniae and L. pneumophila in a single test, and also detect pneumococcal serotypes. In addition, urine antigen detection tests have shown a high specificity, which means that a positive result practically indicates the causative pathogen of CAP. Therefore, a positive result can lead to a targeted therapy that is likely to improve patient outcomes and reduce the risk of resistance and adverse events. However, well-designed studies are needed to evaluate the usefulness of urine antigen detection tests with regard to clinical outcomes.
Asunto(s)
Antígenos Bacterianos/orina , Infecciones Comunitarias Adquiridas/diagnóstico , Neumonía Bacteriana/diagnóstico , Adulto , Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Infecciones Comunitarias Adquiridas/microbiología , Farmacorresistencia Bacteriana , Hospitalización , Humanos , Legionella pneumophila/aislamiento & purificación , Enfermedad de los Legionarios/diagnóstico , Enfermedad de los Legionarios/microbiología , Neumonía Bacteriana/microbiología , Neumonía Neumocócica/diagnóstico , Neumonía Neumocócica/microbiología , Sensibilidad y Especificidad , Streptococcus pneumoniae/aislamiento & purificaciónRESUMEN
BACKGROUND: Streptococcus pneumoniae is a leading cause of pneumonia worldwide. However, the burden of pneumococcal pneumonia among adults in low- and middle-income countries is not well described. METHODS: Data from 2008-2012 was analyzed from two surveillance sites in Guatemala to describe the incidence of pneumococcal pneumonia in adults. A case of hospitalized pneumococcal pneumonia was defined as a positive pneumococcal urinary antigen test or blood culture in persons aged ≥ 18 years hospitalized with an acute respiratory infection (ARI). RESULTS: Among 1595 adults admitted with ARI, 1363 (82%) had either urine testing (n = 1286) or blood culture (n = 338) performed. Of these, 188 (14%) had pneumococcal pneumonia, including 173 detected by urine only, 8 by blood culture only, and 7 by both methods. Incidence rates increased with age, with the lowest rate among 18-24 year-olds (2.75/100,000) and the highest among ≥65 year-olds (31.3/100,000). The adjusted incidence of hospitalized pneumococcal pneumonia was 18.6/100,000 overall, with in-hospital mortality of 5%. CONCLUSIONS: An important burden of hospitalized pneumococcal pneumonia in adults was described, particularly for the elderly. However, even adjusted rates likely underestimate the true burden of pneumococcal pneumonia in the community. These data provide a baseline against which to measure the indirect effects of the 2013 introduction of the pneumococcal conjugate vaccine in children in Guatemala.
Asunto(s)
Mortalidad Hospitalaria , Hospitalización/estadística & datos numéricos , Neumonía Neumocócica/epidemiología , Adolescente , Adulto , Anciano , Antígenos Bacterianos/sangre , Antígenos Bacterianos/orina , Femenino , Guatemala/epidemiología , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Vacunas Neumococicas/uso terapéutico , Neumonía Neumocócica/diagnóstico , Neumonía Neumocócica/microbiología , Streptococcus pneumoniae/aislamiento & purificación , Adulto JovenRESUMEN
BACKGROUND: In US and European literature, Legionella pneumophila is reported as an important etiologic agent of severe community-acquired pneumonia (CAP), but in Chile this information is lacking. The aim of this study was to determine the incidence and identify predictors of severe CAP caused by L pneumophila in Santiago, Chile. METHODS: A multicenter, prospective clinical study lasting 18 months was conducted; it included all adult patients with severe CAP admitted to the ICUs of four hospitals in Santiago. We excluded patients who were immunocompromised, had been hospitalized in the previous 4 weeks, or presented with another disease during their hospitalization. All data for the diagnosis of severe CAP were registered, and urinary antigens for L pneumophila serogroup 1 were determined. RESULTS: A total of 104 patients with severe CAP were included (mean ± SD age, 58.3 ± 19.3 years; men, 64.4%; APACHE (Acute Physiology and Chronic Health Evaluation) II score, 16.7 ± 6.3; Sepsis-related Organ Failure Assessment score, 6.1 ± 3.2; Pitt Bacteremia Score, 3.4 ± 2.5; Pao2/Fio2, 170.8 ± 87.1). An etiologic agent was identified in 62 patients (59.6%), with the most frequent being Streptococcus pneumoniae (27 patients [26%]) and L pneumophila (nine patients [8.6%]). Logistic regression analysis showed that a plasma sodium level of ≤ 130 mEq/L was an independent predictor for L pneumophila severe CAP (OR, 11.3; 95% CI, 2.5-50.5; P = .002). Global mortality was 26% and 33% for L pneumophila. The Pitt bacteremia score and pneumonia score index were the best predictors of mortality. CONCLUSIONS: We found that in Santiago, L pneumophila was second to S pneumoniae as the etiologic agent of severe CAP. Severe hyponatremia at admission appears to be an indicator for L pneumophila etiology in severe CAP.
Asunto(s)
Infecciones Comunitarias Adquiridas/microbiología , Legionella pneumophila/fisiología , Enfermedad de los Legionarios/complicaciones , Neumonía/microbiología , APACHE , Adulto , Anciano , Anciano de 80 o más Años , Antígenos Bacterianos/orina , Chile/epidemiología , Infecciones Comunitarias Adquiridas/epidemiología , Comorbilidad , Femenino , Humanos , Hiponatremia/epidemiología , Legionella pneumophila/inmunología , Modelos Logísticos , Masculino , Persona de Mediana Edad , Infecciones Neumocócicas/complicaciones , Neumonía/epidemiología , Estudios Prospectivos , Índice de Severidad de la Enfermedad , Streptococcus pneumoniae/inmunología , Streptococcus pneumoniae/fisiología , Adulto JovenRESUMEN
A prospective cohort study of adult patients hospitalized due to community-acquired pneumonia was carried out for 1 year in a Brazilian university general hospital to detect the incidence of community-acquired pneumonia by Legionella pneumophila serogroups 1-6. During a whole year, a total of 645 consecutive patients who were hospitalized due to a initial presumptive diagnosis of respiratory disease by ICD-10 (J00-J99), excluding upper respiratory diseases, were screened to detect the patients with community-acquired pneumonia. Fifty-nine consecutive patients hospitalized due to community-acquired pneumonia between July 19, 2000 and July 18, 2001, were included in the study. They had determinations of serum antibodies to L. pneumophila serogroups 1-6 by indirect immunofluorescence antibody test at the Infectious Diseases Laboratory of University of Louisville (KY, USA) and urinary antigen tests for L. pneumophila serogroup 1. Three patients had community-acquired pneumonia by L. pneumophila serogroups 1-6, two patients being diagnosed by seroconversion and positive urinary antigen tests; the other had negative serologies but strongly positive urinary antigen test. The incidence of community-acquired pneumonia by L. pneumophila serogroups 1-6 in our hospital was 5.1%.
Asunto(s)
Legionella pneumophila/clasificación , Enfermedad de los Legionarios/epidemiología , Adolescente , Adulto , Anciano , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/orina , Brasil/epidemiología , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Técnica del Anticuerpo Fluorescente Indirecta , Hospitalización , Humanos , Incidencia , Legionella pneumophila/inmunología , Legionella pneumophila/aislamiento & purificación , Enfermedad de los Legionarios/diagnóstico por imagen , Enfermedad de los Legionarios/microbiología , Persona de Mediana Edad , Selección de Paciente , Estudios Prospectivos , Tomografía Computarizada por Rayos XRESUMEN
Streptococcus pneumoniae and Haemophilus influenzae type b are the main agents of bacterial community-acquired pneumonia in developing countries, although a definite etiologic diagnosis cannot be established in most cases. This study was carried out to assess the performance of a latex particle agglutination test (LPAT) from a commercial kit (Slidex Méningite Kit trade mark, BioMérieux, France) in diagnosing pneumococcal and H. influenzae type b pneumonia. One hundred and seven children (45 ill subjects and 62 healthy controls) were enrolled. All 45 cases had a presumptive diagnosis of bacterial pneumonia based on clinical (WHO criteria), laboratory (white blood cell count > or = 15.000/mm3, polymorphonuclear leukocytes > or = 70%, bands > or = 500/mm3, and C-reactive protein > or = 40 mg/l), and radiological findings, i.e., two or more positive points in the scoring system described by Khamapirad and Glezen (Semin Respir Infect 1987;2:130-144). Clinical, laboratory, and radiological assessments were performed in a blinded manner. LPAT was performed in urine samples after concentration through an ethanol-acetone solution. Sensitivity, specificity, and positive and negative predictive values were 77.3% (95% CI, 61.8-88.0%), 90.3% (95% CI, 79.5-96.0%), 85.0% (95% CI, 69.5-93.8%), and 84.8% (95% CI, 73.4-92.1%), respectively. Results suggest that LPAT is a useful diagnostic tool for the etiologic diagnosis of S. pneumoniae and H. influenzae type b pneumonia, especially in the developing world.
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Antígenos Bacterianos/orina , Infecciones por Haemophilus/diagnóstico , Haemophilus influenzae tipo b/inmunología , Neumonía Bacteriana/diagnóstico , Neumonía Neumocócica/diagnóstico , Streptococcus pneumoniae/inmunología , Estudios de Casos y Controles , Niño , Preescolar , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/inmunología , Femenino , Infecciones por Haemophilus/inmunología , Humanos , Pruebas de Fijación de Látex/métodos , Masculino , Microesferas , Neumonía Bacteriana/inmunología , Neumonía Neumocócica/inmunología , Juego de Reactivos para Diagnóstico , Sensibilidad y EspecificidadRESUMEN
Legionella pneumophila is the second cause of severe community acquired pneumonia. In Chile, however, there are few reports of pneumonia caused by Legionella. We report eight patients (6 men, aged 42 to 72 years old) with community-acquired pneumonia caused by Legionella pneumophila serogroup 1, confirmed by the measurement of urinary antigen. Clinical presentation was characterized by fever or hypothermia (in one case), cough, dyspnea and neurological abnormalities in four patients. Cigarette smoking was the most frequently identified risk factor. All patients had at least one American Thoracic Society severity criteria. Complications observed were acute hypoxemic respiratory failure in seven patients, shock in four, renal failure in four and need for mechanical ventilation in three. No patient died.
Asunto(s)
Legionella pneumophila/inmunología , Enfermedad de los Legionarios/orina , Adulto , Anciano , Antígenos Bacterianos/orina , Chile , Infecciones Comunitarias Adquiridas/microbiología , Infecciones Comunitarias Adquiridas/orina , Femenino , Humanos , Legionella pneumophila/aislamiento & purificación , Masculino , Persona de Mediana Edad , Índice de Severidad de la EnfermedadRESUMEN
Legionella pneumophila is the second cause of severe community acquired pneumonia. In Chile, however, there are few reports of pneumonia caused by Legionella. We report eight patients (6 men, aged 42 to 72 years old) with community-acquired pneumonia caused by Legionella pneumophila serogroup 1, confirmed by the measurement of urinary antigen. Clinical presentation was characterized by fever or hypothermia (in one case), cough, dyspnea and neurological abnormalities in four patients. Cigarette smoking was the most frequently identified risk factor. All patients had at least one American Thoracic Society severity criteria. Complications observed were acute hypoxemic respiratory failure in seven patients, shock in four, renal failure in four and need for mechanical ventilation in three. No patient died
Asunto(s)
Humanos , Masculino , Adulto , Femenino , Persona de Mediana Edad , Enfermedad de los Legionarios , Legionella pneumophila , Neumonía Bacteriana/etiología , Enfermedad de los Legionarios , Legionella pneumophila , Antígenos Bacterianos/orina , Antígenos BacterianosRESUMEN
OBJECTIVE: To compare first-voided urine specimens with paired endocervical swab specimens from women to determine the role of urine in complementing or replacing swab specimens for the detection of the chlamydial antigen. DESIGN: For 18 months, both endocervical swab specimens (the criterion standard) and urine specimens were tested for the chlamydial antigen, using an enzyme-linked immunosorbent assay (Chlamydiazyme, Abbott Laboratories, North Chicago, Ill). Positive results were confirmed using a blocking reagent (Abbott Laboratories) and/or a direct fluorescent antibody test (Micro-Trak, Syva, Palo Alto, Calif). A low level of chlamydial antigen (below the enzyme-linked immunosorbent assay threshold recommended by the manufacturer) was also looked for and, when found, was confirmed by the direct fluorescent antibody test. SETTING: Prenatal and family practice clinics in a 500-bed community hospital. PATIENTS: Specimens were collected from 489 random asymptomatic or symptomatic women. MAIN OUTCOME MEASURE: The detection of the chlamydial antigen from endocervical swab specimens was compared with the detection from first-voided urine specimens. RESULTS: Acceptable swab and urine specimens were obtained from 300 (61.3%) of the patients. The antigen of Chlamydia trachomatis was confirmed in 20 (6.7%) of the 300 women. Of the infected patients, the antigen was detected in both swab and urine specimens for nine patients (45%), only in the swab specimens for eight (40%), and only in the urine specimens for three (15%). Testing urine in addition to endocervical swab specimens allowed for the detection of 18% more chlamydial infections, whereas confirming the presence of the antigen below the enzyme-linked immunosorbent assay cutoff resulted in the detection of 54% more infections. CONCLUSIONS: Collecting multiple specimens and testing for low levels of chlamydial antigen may significantly improve the detection of chlamydial infections in women. First-voided urine may be an appropriate complementary specimen to endocervical swab specimens, but urine by itself does not allow for the adequate detection of the chlamydial antigen in women.
Asunto(s)
Antígenos Bacterianos/análisis , Infecciones por Chlamydia/diagnóstico , Chlamydia trachomatis/inmunología , Antígenos Bacterianos/orina , Infecciones por Chlamydia/orina , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Sensibilidad y Especificidad , Manejo de Especímenes/métodosRESUMEN
Although cases of community-acquired Legionnaires' disease have been epidemiologically linked to residential water supplies, the risk of acquiring Legionnaires' disease from exposure to Legionella pneumophila in residential water systems is uncertain. The residential water supplies of 218 members of the American Legion in six different geographical areas in Pittsburgh were cultured for L. pneumophila. Residents of the homes provided a recent medical history and a blood sample for detection of antibodies to legionella. A urine sample for legionella urinary antigen testing was also requested from individuals residing in legionella-positive homes and individuals with a positive antibody test. Six percent (14/218) of the homes yielded L. pneumophila (range within six areas 0-22%). Lower hot water tank temperature was significantly associated with legionella positivity (P less than 0.01). Analysis of water samples for mineral content showed no association between legionella positivity and concentrations of calcium and magnesium. Water samples from the area where 22% of the homes surveyed were positive for legionella had a higher iron content than water samples from the other areas tested. None of the individuals residing in legionella-positive homes showed elevated antibody titres to legionella or the presence of legionella antigen in urine. For the immunocompetent hosts, the risk of contracting Legionnaires' disease from exposure to contaminated household water supplies in the Pittsburgh area appears to be low.
Asunto(s)
Legionella pneumophila/aislamiento & purificación , Enfermedad de los Legionarios/epidemiología , Microbiología del Agua , Abastecimiento de Agua , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/orina , Calor , Humanos , Legionella pneumophila/inmunología , Persona de Mediana Edad , Minerales/análisis , Análisis Multivariante , Prevalencia , Abastecimiento de Agua/análisisRESUMEN
The incidence of antigenuria was documented after vaccination of 75 children 15 to 60 months of age with one of three Haemophilus influenzae type b conjugate vaccines, PRP-D (ProHIBiT), PRP-T and HbOC (HibTITER). Unconcentrated and concentrated urine was tested on the first, third, fifth and seventh days after vaccination. Antigenuria occurred on Day 1 in 100% of PRP-D, 43% of PRP-T and 12% of HbOC recipients. The percentages of children excreting antigen on Day 3 were 95, 17 and 8%; on Day 5 they were 36, 4 and 12%; and on Day 7 they were 14, 0 and 18% for PRP-D, PRP-T and HbOC, respectively. The difference in the occurrence of antigenuria resulting from each vaccine was statistically significant on Day 1 and for PRP-D compared with PRP-T or HbOC on Day 3. It is important for clinicians to be aware of the frequency with which antigenuria occurs after these vaccines so that appropriate therapeutic decisions can be made.
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Antígenos Bacterianos/orina , Proteínas Bacterianas/inmunología , Vacunas Bacterianas/inmunología , Toxoide Diftérico/inmunología , Vacunas contra Haemophilus , Haemophilus influenzae/inmunología , Toxoide Tetánico/inmunología , Preescolar , Infecciones por Haemophilus/diagnóstico , Infecciones por Haemophilus/prevención & control , Humanos , Lactante , Pruebas de Fijación de Látex , Factores de Tiempo , Vacunación , Vacunas Sintéticas/inmunologíaRESUMEN
Foi desenvolvido um metodo de precipitacao de antigenos polissacaridicos de S. pneumoniae e H influenzae tipo b na urina, atraves do tratamento com uma solucao de etnol-acetona 1:1 seguido de um tratamento a quente com EDTA 0,1M. Foram empregadas as tecnicas de contra-imunoeletroforese e latex aglutinacao para a deteccao de antigenos polissacarideos em amostras pareadas de urina e soro e ainda de liquido pleural, de criancas com diagnostico clinico e radiologico de pneumonia aguda. Contra-imunoeletroforese e latex aglutinacao apresentaram melhores indices de sensibilidade em urina do que em soro e tiveram otimo desempenho tanto para urina de volume inicial relativamente pequeno como de grande volume, colhidas antes ou durante os primeiros dias de antibioticoterapia. Os resultados obtidos em contra-imunoeletroforese e latex aglutinacao mostraram que a solucao etanol-acetona 1:1 fornece melhor rendimento na precipitacao de antigeno polissacaridico enquanto que o aquecimento com EDTA diminui a probabilidade de ocorrencia de resultados falso-positivos e de reatividade cruzada entre S. pneumoniae e H. influenzae tipo b. A urina mostrou-se como importante meio de deteccao de antigenos bacterianos no diagnostico de pneumonia bacteriana aguda, principalmente se a antibioticoterapia previa obstrui o crescimento bacteriano nos meios de cultura.
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Humanos , Recién Nacido , Lactante , Preescolar , Niño , Antígenos Bacterianos/análisis , Haemophilus influenzae/inmunología , Neumonía/diagnóstico , Streptococcus pneumoniae/inmunología , Enfermedad Aguda , Antígenos Bacterianos/sangre , Antígenos Bacterianos/orina , Contrainmunoelectroforesis , Pruebas Inmunológicas/métodos , Pruebas de Fijación de Látex/métodos , Derrame Pleural/diagnóstico , Valor Predictivo de las PruebasRESUMEN
We assessed the clinical significance of a reactive urine latex agglutination (LA) test in neonates without bacteriologically confirmed group B streptococcal (GBS) infection. In a retrospective review of a 3 1/2-month period, during which 367 urine specimens from newborn infants evaluated for suspected sepsis were tested by LA, 25 infants (6.9%) with sterile blood cultures but positive urine LA test results were compared with a control group of 112 infants with both blood cultures and urine LA test results negative for GBS. When the data were studied with stepwise discriminant analysis, the only variables significantly associated with a positive urine LA test result were immature to total neutrophil ratios greater than or equal to 0.16 at 0 and 12 hours. The influence of mucosal GBS colonization on urine LA test results was then investigated prospectively in 98 healthy infants (83 born to mothers colonized with GBS and 15 born to mothers with negative GBS cultures). Eight (8.2%) of the infants studied, or 8 of 52 (15.4%) infants colonized with GBS, had a positive urine LA test result. GBS was isolated from urine cultures of all infants with a positive urine LA test result. A positive urine LA test result was associated with positive GBS rectal and vaginal cultures and with increased density of colonization at those sites. We conclude that contamination of bag specimens of urine with GBS from perineal and rectal colonization may produce a positive urine LA test result in an infant with no systemic sign of infection.
Asunto(s)
Antígenos Bacterianos/orina , Recién Nacido/inmunología , Infecciones Estreptocócicas/diagnóstico , Streptococcus agalactiae/inmunología , Antígenos Bacterianos/análisis , Femenino , Humanos , Recién Nacido/sangre , Recién Nacido/orina , Pruebas de Fijación de Látex , Recuento de Leucocitos , Masculino , Intercambio Materno-Fetal , Membrana Mucosa/microbiología , Neutrófilos/patología , Embarazo , Estudios Prospectivos , Recto/microbiología , Estudios Retrospectivos , Infecciones Estreptocócicas/sangre , Infecciones Estreptocócicas/transmisión , Infecciones Estreptocócicas/orina , Streptococcus agalactiae/aislamiento & purificación , Vagina/microbiologíaRESUMEN
An inhibition of immunohemolysis assay was used to detect the enterobacterial common antigen (ECA) in urine samples from 40 children with cancer. Seven patients were excluded because bacterial contamination of urine. Thirty of the remaining 33 sterile samples gave an ECA-positive reaction. Specimens from 30 healthy control were negative. These findings may reflect a vascular dissemination and glomerular filtration of gram-negative lipopolysaccharide residues as a consequence of the malignancy. Detection of ECA in urine may be an useful tool for investigating the evolution of neoplastic diseases in the absence of urinary tract infections.
Asunto(s)
Antígenos Bacterianos/orina , Enterobacteriaceae/inmunología , Neoplasias/orina , Niño , Preescolar , Pruebas de Fijación del Complemento , Enterobacteriaceae/fisiología , Humanos , Síndromes de Inmunodeficiencia/etiología , Síndromes de Inmunodeficiencia/orina , Lactante , Absorción Intestinal , Intestinos/microbiología , Lipopolisacáridos/metabolismo , Neoplasias/inmunología , Neoplasias/microbiologíaRESUMEN
La detección de antígenos bacterianos en distintos fluidos corporales ha sido usada como método de detección de infecciones bacterianas, demostrándose recientemente mayor positividad en orina concentrada en relación al suero. Se presenta la técnica de detección de antígenos bacterianos por aglutinación por látex, en orina concentrada 50 veces mediante un sistema de ultrafiltrado Minicom y el uso de antisuero Bactigen para Haemophilus influenzae y Streptococcus pneumoniae. Se describe la participación de estos agentes en las IRAB del lactante menor de 1 año hospitalizado. Se estudian 3 grupos: Grupo A (control positivo): 7 casos, todos con aglutinación positiva. Grupo B (controles sanos): 3/16 con aglutinación positiva sólo para Haemophilus influenzae. Grupo C (pacientes con IRAB): 10/77 casos con aglutinación positiva a Haemophilus influenzae y sólo 2/77 positivos a Streptococcus pneumoniae. Se presenta un nuevo método de diagnóstico precoz, el que sugiere en forma preliminar que la obtención de antígenos en orina es un método útil en el diagnóstico etiológico de infecciones bacterianas y que el hallazgo de Streptococcus pneumoniae sería escaso en los lactantes menores de 1 año con IRAB. Se discute el hallazgo predominante de Haemophilus influenzae
Asunto(s)
Lactante , Humanos , Masculino , Femenino , Antígenos Bacterianos/orina , Haemophilus influenzae/inmunología , Infecciones del Sistema Respiratorio/diagnóstico , Streptococcus pneumoniae/inmunología , Pruebas de Fijación de Látex , Infecciones del Sistema Respiratorio/etiologíaRESUMEN
Demonstration of bacterial antigens in biological fluids has been used for early detection of bacterial infections. Recent evidence suggests that higher detection rates of these antigens can be obtained from concentrated urine than from serum samples of patients. Evidence of bacterial infection by antigen detection was looked for from 50 fold concentrated urine samples by means of an ultrafilter system (Minicom) and latex agglutination for Haemophilus influenzae B (HiB) and Streptococcus pneumoniae (Sp) in three groups of patients. Group A (Positive controls), included 7 patients whose blood culture were positive for HiB (n = 5) and Sp (n = 2). Group B (Healthy controls) involved 16 children without clinical and laboratory signs of infection, coming from ambulatory well baby clinics and surgical wards, and group C was formed by 77 patients with negative blood cultures but with clinical and X ray evidence of lower respiratory tract infection. The corresponding antigen was demonstrated in urine samples from all group A patients. Three group B subjects gave positive results for HiB antigen. HiB antigen was detected from 10 and Sp antigen from 2 group C patients. These results suggest that the search for bacterial antigens in urine would be useful for etiological diagnosis and management of patients with bacterial pneumoniae. There is no definite explanation for the finding of HiB antigen in urine from apparently healthy children but the possibility of previous or actual asymptomatic infections must be taken into account.