RESUMEN
The transmission of tuberculosis (TB) in bars is difficult to study. The objective was to describe a large TB outbreak in a company's bar and other leisure settings. A descriptive study of a TB outbreak was carried out. Contacts were studied in the index case's workplace bar (five circles of contacts) and other recreational areas (social network of three bars in the index case's neighbourhood). Chest X-rays were recommended to contacts with positive tuberculin skin tests (TST) (⩾5 mm). The risk of latent tuberculosis infection (LTBI) was determined using an adjusted odds ratio. The dose-response relationship was determined using the chi-square test for linear trend. We studied 316 contacts at the index case's workplace and detected five new cases of TB. The prevalence of LTBI was 57·9% (183/316) and was higher in the first circle, 96·0% (24/25), and lower in the fifth, 46·5% (20/43) (P < 0·0001). Among 58 contacts in the three neighbourhood bars, two TB cases were detected and the LTBI prevalence was 51·7% (30/58). Two children of one secondary TB company patient became ill. Bars may be transmission locations for TB and, as they are popular venues for social events, should be considered as potential areas of exposure.
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Brotes de Enfermedades/estadística & datos numéricos , Tuberculosis Latente/epidemiología , Tuberculosis Latente/transmisión , Instalaciones Públicas , Adolescente , Adulto , Niño , Preescolar , Trazado de Contacto , Femenino , Humanos , Actividades Recreativas , Masculino , Persona de Mediana Edad , España/epidemiología , Adulto JovenRESUMEN
El presente artículo no revisa únicamente aquellos aspectos de la neumonía adquirida en la comunidad fundamentales para la práctica clínica diaria, sino que incide en los temas polémicos, y aporta la información más novedosa disponible. Se considera la neumonía adquirida en la comunidad en un sentido amplio, sin excluir ciertas variantes que, durante los últimos años, algunos autores han llegado a deslindar, como la neumonía asociada a cuidados sanitarios. Esta última no es más que la misma enfermedad que incide en pacientes más frágiles, con un mayor número de factores de riesgo, compartiendo ambas un planteamiento global común (AU)
This article not only reviews the essential aspects of community-acquired pneumonia for daily clinical practice, but also highlights the controversial issues and provides the newest available information. Community-acquired pneumonia is considered in a broad sense, without excluding certain variants that, in recent years, a number of authors have managed to delineate, such as healthcare-associated pneumonia. The latter form is nothing more than the same disease that affects more frail patients, with a greater number of risk factors, both sharing an overall common approach (AU)
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Femenino , Humanos , Masculino , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/prevención & control , Neumonía/epidemiología , Neumonía/prevención & control , Factores de Riesgo , Pronóstico , Biomarcadores , Radiografía Torácica/instrumentación , Radiografía Torácica/métodos , Infecciones Neumocócicas/epidemiología , Infecciones Neumocócicas/prevención & control , Streptococcus pneumoniae/aislamiento & purificaciónRESUMEN
This article not only reviews the essential aspects of community-acquired pneumonia for daily clinical practice, but also highlights the controversial issues and provides the newest available information. Community-acquired pneumonia is considered in a broad sense, without excluding certain variants that, in recent years, a number of authors have managed to delineate, such as healthcare-associated pneumonia. The latter form is nothing more than the same disease that affects more frail patients, with a greater number of risk factors, both sharing an overall common approach.
RESUMEN
We aimed to determine the incidence, clinical consequences and microbiological findings related to the presence of pleural effusion in community-acquired pneumonia, and to identify predictive factors for empyema/complicated parapneumonic effusion. We analysed 4,715 consecutive patients with community-acquired pneumonia from two acute care hospitals. Patients were classified into three groups: no pleural effusion, uncomplicated parapneumonic effusion and empyema/complicated parapneumonic effusion. A total of 882 (19%) patients had radiological evidence of pleural fluid, of whom 261 (30%) met criteria for empyema/complicated parapneumonic effusion. The most important event related to the presence of uncomplicated parapneumonic effusion was a longer hospital stay. Relevant clinical and microbiological consequences were associated with empyema/complicated parapneumonic effusion. Five independent baseline characteristics could predict the development of empyema/complicated parapneumonic effusion: age < 60 yrs (p = 0.012), alcoholism (p = 0.002), pleuritic pain (p = 0.002), tachycardia >100 beats·min⻹ (p = 0.006) and leukocytosis >15,000 mm⻳ (p < 0.001). A higher incidence of anaerobes and Gram-positive cocci was found in this subgroup of patients. We conclude that only the development of empyema/complicated parapneumonic effusion carried relevant consequences; this condition should be suspected in the presence of some baseline characteristics and managed by using antimicrobials active against Gram-positive cocci and anaerobes.
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Derrame Pleural/etiología , Neumonía Bacteriana/complicaciones , Adulto , Anciano , Antibacterianos/uso terapéutico , Infecciones Comunitarias Adquiridas , Empiema Pleural/diagnóstico , Empiema Pleural/tratamiento farmacológico , Empiema Pleural/etiología , Empiema Pleural/microbiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Derrame Pleural/diagnóstico , Derrame Pleural/tratamiento farmacológico , Derrame Pleural/microbiología , Neumonía Bacteriana/tratamiento farmacológico , Neumonía Bacteriana/microbiología , Pronóstico , Factores de RiesgoRESUMEN
BACKGROUND: Recommendations for diagnostic testing in hospitalised patients with community-acquired pneumonia remain controversial. The aim of the present study was to evaluate the impact of a therapeutic strategy based on the microbiological results provided by urinary antigen tests for Streptococcus pneumoniae and Legionella pneumophila. METHODS: For a 2-year period, hospitalised patients with community-acquired pneumonia were randomly assigned to receive either empirical treatment, according to international guidelines, or targeted treatment, on the basis of the results from antigen tests. Outcome parameters, monetary costs and antibiotic exposure levels were compared. RESULTS: Out of 194 enrolled patients, 177 were available for randomisation; 89 were assigned to empirical treatment and 88 were assigned to targeted treatment. Targeted treatment was associated with a slightly higher overall cost (euro 1657.00 vs euro 1617.20, p=0.28), reduction in the incidence of adverse events (9% vs 18%, p=0.12) and lower exposure to broad-spectrum antimicrobials (154.4 vs 183.3 defined daily doses per 100 patient days). No statistically significant differences in other outcome parameters were observed. Oral antibiotic treatment was started according to the results of antigen tests in 25 patients assigned to targeted treatment; these patients showed a statistically significant higher risk of clinical relapse as compared with the remaining population (12% vs 3%, p=0.04). CONCLUSIONS: The routine implementation of urine antigen detection tests does not carry substantial outcome-related or economic benefits to hospitalised patients with community-acquired pneumonia. Narrowing the antibiotic treatment according to the urine antigen results may in fact be associated with a higher risk of clinical relapse.
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Antibacterianos/uso terapéutico , Antígenos Bacterianos/orina , Neumonía Bacteriana/diagnóstico , Neumonía Bacteriana/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/tratamiento farmacológico , Infecciones Comunitarias Adquiridas/economía , Femenino , Costos de la Atención en Salud/estadística & datos numéricos , Hospitalización , Humanos , Legionella/inmunología , Enfermedad de los Legionarios/diagnóstico , Enfermedad de los Legionarios/tratamiento farmacológico , Enfermedad de los Legionarios/economía , Masculino , Persona de Mediana Edad , Neumonía Bacteriana/economía , Neumonía Neumocócica/diagnóstico , Neumonía Neumocócica/tratamiento farmacológico , Neumonía Neumocócica/economía , Estudios Prospectivos , Streptococcus pneumoniae/inmunología , Resultado del TratamientoRESUMEN
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Humanos , Electromiografía/métodos , Pacientes Ambulatorios , Neurología , Necesidades y Demandas de Servicios de Salud/estadística & datos numéricos , Estudios Prospectivos , Síndrome del Túnel Carpiano/diagnóstico , Síndrome del Túnel Carpiano/epidemiología , Hospitales GeneralesAsunto(s)
Acetazolamida/uso terapéutico , Neuralgia del Trigémino/tratamiento farmacológico , Cefalalgias Vasculares/tratamiento farmacológico , Anciano , Anticonvulsivantes/uso terapéutico , Femenino , Humanos , Síndrome , Resultado del Tratamiento , Neuralgia del Trigémino/complicaciones , Neuralgia del Trigémino/diagnóstico , Cefalalgias Vasculares/complicaciones , Cefalalgias Vasculares/diagnósticoRESUMEN
BACKGROUND: Community-acquired pneumonia frequently constitutes a nonsevere infection manageable at home. However, for these low-risk episodes, the epidemiological features have not been carefully analyzed. OBJECTIVES: To determine the cause of nonsevere community-acquired pneumonia and to investigate if a correlation exists between cause and severity or comorbidity. METHODS: During a 3-year period, all patients with nonsevere community-acquired pneumonia, according to the Pneumonia Patient Outcome Research Team prognostic classification (patients in groups 1-3), were included in the study. Causes were investigated through the following procedures: cultures of blood, sputum, and pleural fluid; serologic tests; and polymerase chain reaction methods to detect Streptococcus pneumoniae DNA in whole blood or Mycoplasma pneumoniae and Chlamydia pneumoniae DNA in throat swab specimens. RESULTS: Of 317 initially included patients, 247 were eligible for the study. A microbial diagnosis was obtained in 162 patients (66%), and the main pathogens detected were S pneumoniae (69 patients [28%]), M pneumoniae (40 patients [16%]), and C pneumoniae (28 patients [11%]). For the 58 patients in prognostic group 1, M pneumoniae was the most prevalent cause, and atypical microorganisms constituted 40 (69%) of the isolated agents. In contrast, for patients in prognostic groups 2 and 3, S pneumoniae was the leading agent, and a significant reduction of M pneumoniae cases and a greater presence of other more uncommon pathogens were observed. The existence of comorbid conditions was not a determining factor for particular causes. CONCLUSIONS: Among low-risk patients with community-acquired pneumonia, there was a certain correlation between severity and cause. In contrast, the existence of a comorbidity did not have a predictive causative value.
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Neumonía Bacteriana/epidemiología , Neumonía Bacteriana/microbiología , Adulto , Anciano , Infecciones por Chlamydophila/epidemiología , Chlamydophila pneumoniae/aislamiento & purificación , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/microbiología , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycoplasma pneumoniae/aislamiento & purificación , Neumonía por Mycoplasma/epidemiología , Neumonía Neumocócica/epidemiología , Reacción en Cadena de la Polimerasa , Pronóstico , Índice de Severidad de la Enfermedad , Streptococcus pneumoniae/aislamiento & purificaciónRESUMEN
Although initial presentation has been commonly used to select empirical therapy in patients with community-acquired pneumonia (CAP), few studies have provided a quantitative estimation of its value. The objective of this study was to analyse whether a combination of basic clinical and laboratory information performed at bedside can accurately predict the aetiology of pneumonia. A prospective study was developed among patients admitted to the Emergency Department University Hospital Arnau de Vilanova, Lleida, Spain, with CAP. Informed consent was obtained from patients in the study. At entry, basic clinical (age, comorbidity, symptoms and physical findings) and laboratory (white blood cell count) information commonly used by clinicians in the management of respiratory infections, was recorded. According to microbiological results, patients were assigned to the following categories: bacterial (Streptococcus pneumoniae and other pyogenic bacteria), virus-like (Mycoplasma pneumoniae, Chlamydia spp and virus) and unknown pneumonia. A scoring system to identify the aetiology was derived from the odds ratio (OR) assigned to independent variables, adjusted by a logistic regression model. The accuracy of the prediction rule was tested by using receiver operating characteristic curves. One hundred and three consecutive patients were classified as having virus-like (48), bacterial (37) and unknown (18) pneumonia, respectively. Independent predictors related to bacterial pneumonia were an acute onset of symptoms (OR 31; 95% CI, 6-150), age greater than 65 or comorbidity (OR 6.9; 95% CI, 2-23), and leukocytosis or leukopenia (OR 2; 95% CI, 0.6-7). The sensitivity and specificity of the scoring system to identify patients with bacterial pneumonia were 89% and 94%, respectively. The prediction rule developed from these three variables classified the aetiology of pneumonia with a ROC curve area of 0.84. Proper use of basic clinical and laboratory information is useful to identify the aetiology of CAP. The prediction rule may help clinicians to choose initial antibiotic therapy.
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Neumonía/etiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/etiología , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neumonía/diagnóstico , Neumonía Bacteriana/diagnóstico , Neumonía Bacteriana/etiología , Neumonía Viral/diagnóstico , Neumonía Viral/etiología , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: Streptococcus pneumoniae is the leading cause of community acquired pneumonia; however, only a small proportion of cases can be detected by conventional methods. The ability of the polymerase chain reaction (PCR) test performed on whole blood samples to identify patients with pneumococcal pneumonia was investigated. METHODS: One hundred and fourteen consecutive adult patients with community acquired pneumonia were evaluated by a wide battery of diagnostic tests in order to determine the aetiology. Blood samples from these patients and 50 controls were also tested by the nested PCR test to detect selected pneumolysin gene fragments of S pneumoniae. RESULTS: The patients were divided into four groups: (1) 40 patients with pneumococcal pneumonia in 22 of whom (55%) the PCR was positive (eight of 11 with bacteraemia and 14 of 29 without); (2) 30 with pneumonia due to other pathogens in all of whom the PCR was negative; (3) 44 with pneumonia of unknown aetiology in 14 of whom (32%) PCR was positive, and (4) 50 controls in whom the PCR test was positive in two (4%). Thus, the sensitivity of the test was 55% and the specificity 100% (81% if positive PCR tests among undiagnosed patients are considered as false positive results). CONCLUSION: PCR applied to whole blood samples appears to be a sensitive and very specific diagnostic test for identifying patients with pneumococcal pneumonia with a potential application in clinical practice.
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Neumonía Neumocócica/diagnóstico , Reacción en Cadena de la Polimerasa/métodos , Streptococcus pneumoniae/aislamiento & purificación , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Infecciones Comunitarias Adquiridas/sangre , Infecciones Comunitarias Adquiridas/diagnóstico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neumonía Neumocócica/sangre , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: To assess the impact of the use of a therapeutic strategy based on classifying patients with community-acquired pneumonia (CAP) according to the probability of short-term mortality. PATIENTS AND METHODS: During one year, all patients admitted to the Emergency Department with diagnosis of CAP were included. Clinicians were invited to treat patients according to a recently published protocol that stratifies patients into five categories (from low to high-risk mortality): patients assigned to class 1 were managed at home; patients included in classes 2 and 3 were assigned to a short-time period at emergency department before managed at home; and patients assigned to classes 4 and 5 were hospitalized. RESULTS: The final population analyzed included 101 patients. The rate of acceptability among clinicians was 96.7%. Patients were classified by the following terms: risk-class 1: 17 (16.8%); risk-classes 2 and 3: 40 (39.7%); risk-classes 4 and 5: 44 (43.6%). During follow-up, of the 57 non-hospitalized patients, 3 (5.2%) were subsequently admitted to hospital and 7 (12.2%) patients initially assigned to a short-time period at emergency department were hospitalized, and 1 (1.7%) of them died. By this program, the reduction of the hospitalization rate was 23.8%. CONCLUSION: A strategy of management of CAP based on a prognostic classification has a good safety and acceptability among clinicians, and reduces the rate of hospitalizations.
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Neumonía/mortalidad , Neumonía/terapia , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Infecciones Comunitarias Adquiridas/mortalidad , Infecciones Comunitarias Adquiridas/terapia , Urgencias Médicas , Femenino , Hospitalización , Humanos , Tiempo de Internación , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo , Factores de TiempoRESUMEN
PURPOSE: Although a wide variety of recognized pathogens can cause community-acquired pneumonia, in many patients the etiology remains unknown after routine diagnostic workup. The aim of this study was to identify the causal agent in these patients by obtaining lung aspirates with transthoracic needle aspiration. SUBJECTS AND METHODS: During a 15-month period, all consecutive patients with community-acquired pneumonia who were eligible for transthoracic needle aspiration were enrolled in the study. In addition to conventional microbial methods (culture of blood and sputum, serologic studies), we performed cultures and genetic and antigen tests for common respiratory pathogens in lung aspirates. RESULTS: The study group consisted of 109 patients. Conventional microbial studies identified an etiology in 54 patients (50%), including Mycoplasma pneumoniae in 19 patients, Chlamydia pneumoniae in 9 patients, and Streptococcus pneumoniae in 9 patients. Among the remaining 55 patients, study of the lung aspiration provided evidence of the causal agent in 36 (65%). In 4 additional patients with a single microbial diagnosis by conventional methods, the lung sample provided evidence of an additional microorganism. The new pathogens detected by lung aspiration were S. pneumoniae in 18 patients, Haemophilus influenzae in 6 patients, Pneumocystis carinii in 4 patients, and C. pneumoniae in 3 patients; other organisms were identified in 4 patients. CONCLUSIONS: In our study, S. pneumoniae was the leading cause of community-acquired pneumonia, accounting for 25% of all cases, including about one-third of the cases the cause of which could not be ascertained with routine diagnostic methods.
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Infecciones Comunitarias Adquiridas/microbiología , Neumonía Bacteriana/microbiología , Streptococcus pneumoniae/aislamiento & purificación , Succión , Adulto , Anciano , Anciano de 80 o más Años , Cartilla de ADN , ADN Bacteriano/química , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Streptococcus pneumoniae/genéticaRESUMEN
Detection of pneumococcal antigen has been used to increase the rate of diagnosis of pneumococcal pneumonia. The present study was designed to determine the value of rapid detection of pneumococcal antigen in samples obtained by transthoracic needle aspiration (TNA) from patients with community-acquired pneumonia (CAP) in a comparative analysis with culture and polymerase chain reaction (PCR). Pneumococcal antigen was detected by latex agglutination. One hundred and ten consecutive patients diagnosed with CAP underwent TNA. Patients were grouped, according to PCR, culture and serological results, into pneumococcal pneumonia (n = 18), other known aetiology (n = 67) and unknown aetiology (n = 25). In patients with pneumococcal pneumonia, antigen was detected in 17 (94.4%) cases. Antigen was detected in one and nine patients with pneumonia of other known or unknown aetiologies, respectively, yielding a specificity of 89.1%. In conclusion, detection of pneumococcal antigen on samples obtained by TNA from patients with CAP provides a sensitive and specific diagnosis of Streptococcus pneumoniae infection. Furthermore, its rapid results would reduce the dependence on empirical treatments.
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Antígenos Bacterianos/análisis , Neumonía Neumocócica/diagnóstico , Streptococcus pneumoniae/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Técnicas Bacteriológicas , Biopsia con Aguja , Infecciones Comunitarias Adquiridas/diagnóstico , Infecciones Comunitarias Adquiridas/microbiología , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Neumonía Bacteriana/diagnóstico , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
OBJECTIVE: Evaluate the effect of HIV infection in the appearance of toxicity in patients treated with rifampin, analysing the involved elements in its genesis. METHODS: We realized a comparative study of the epidemiologic and clinical characteristics, and the incidence of adverse reactions to rifampin (between 1986-1993), comparing the seropositive patients treated with rifampin, during more than 3 months, with one control group, of equal number of patients, without evidence of HIV infection, taken at random, with epidemiologic characteristics (age and sex) similar to the first group and also treated with rifampin during a similar period. In the group with HIV infection, we analysed the related epidemiologic, clinical and analytic characteristics, in a way statistically significative, with the appearance of toxicity to rifampin. RESULTS: The risk of toxicity to rifampin was associated significantly to HIV infection (p < 0.01), without finding any other distinguishing characteristics among the analysed groups. Indicative parameters of advanced HIV infection: advanced clinical stage, minor level of lymphocytes CD4+, total leukocytes, total lymphocytes and quotient CD4+/CD8+, also high levels of beta 2-microglobulinemia and [correction of 2-microglobulina e] IgA, and a negative protein purified derivative test (PPD) were found statistically related with the appearance to toxicity to rifampin. Patients with number of lymphocytes CD4+ between 20-50/mm3, showed a major predisposition of suffering toxicity to rifampin. CONCLUSION: HIV infection involved a notably increase of toxicity risk to rifampin. Clinical or analytic parameters associated with advanced illness conditioned an increase of this risk, essentially among patients with number of CD4+ between 20-50/mm.
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Antibióticos Antituberculosos/efectos adversos , Hipersensibilidad a las Drogas/epidemiología , Infecciones por VIH/inmunología , VIH-1 , Rifampin/efectos adversos , Infecciones Oportunistas Relacionadas con el SIDA/complicaciones , Infecciones Oportunistas Relacionadas con el SIDA/tratamiento farmacológico , Adulto , Hipersensibilidad a las Drogas/etiología , Femenino , Seronegatividad para VIH , Humanos , Inmunidad Celular , Incidencia , Masculino , Factores de Riesgo , España/epidemiología , Tuberculosis Pulmonar/complicaciones , Tuberculosis Pulmonar/tratamiento farmacológicoRESUMEN
STUDY OBJECTIVE: This study was designed to evaluate the usefulness of polymerase chain reaction (PCR) to detect Mycoplasma pneumoniae DNA in samples obtained by transthoracic needle aspiration (TNA). DESIGN: Prospective study of cases. SETTING: A university hospital in Lleida, Spain. PATIENTS: A total of 101 unselected patients, admitted between January 1993 and March 1994 in the emergency department, with a clinical and radiologic picture of community-acquired pneumonia, and without contraindications for TNA application. INTERVENTIONS: Patients were studied with conventional diagnostic techniques for community-acquired pneumonia. In addition, a sample obtained by TNA was processed by the following methods: culture in standard media, culture in selective media for Legionella, detection of capsular antigens for Streptococcus pneumoniae and Haemophilus influenzae, and detection of M pneumoniae specific genome by PCR. RESULTS: Serologic data were not available in eight patients and were excluded from this analysis. M pneumoniae PCR amplification was possible in eight cases, well correlated with serologic responses indicating current infection. Samples from ten additional patients, negative by PCR, were found to be demonstrative of recent M pneumoniae infection by serologic study. Finally, in all the remaining 75 cases, including the 59 patients for whom a different microbial diagnosis was established, M pneumoniae PCR test gave negative results. CONCLUSION: This study indicates that PCR, applied to samples obtained by TNA, appears to be a moderately sensitive and highly specific method for rapid detection of M pneumoniae lung infection.
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Pulmón/microbiología , Mycoplasma pneumoniae/aislamiento & purificación , Neumonía por Mycoplasma/diagnóstico , Reacción en Cadena de la Polimerasa , Adulto , Biopsia con Aguja/métodos , Infecciones Comunitarias Adquiridas , Estudios de Evaluación como Asunto , Humanos , Persona de Mediana Edad , Neumonía por Mycoplasma/patología , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
A prospective, randomized study was conducted to evaluate the role of vitamin B12 and folinic acid supplementation in preventing zidovudine (ZDV)-induced bone marrow suppression. Seventy-five human immunodeficiency virus (HIV)-infected patients with CD4+ cell counts < 500/mm3 were randomized to receive either ZDV (500 mg daily) alone (group I, n = 38) or in combination with folinic acid (15 mg daily) and intramascular vitamin B12 (1000 micrograms monthly) (group II, n = 37). Finally, 15 patients were excluded from the study (noncompliance 14, death 1); thus, 60 patients (31 in group I and 29 in group II) were eligible for analysis. No significant differences between groups were found at enrollment. During the study, vitamin B12 and folate levels were significantly higher in group II patients; however, no differences in hemoglobin, hematocrit, mean corpuscular volume, and white-cell, neutrophil and platelet counts were observed between groups at 3, 6, 9 and 12 months. Severe hematologic toxicity (neutrophil count < 1000/mm3 and/or hemoglobin < 8 g/dl) occurred in 4 patients assigned to group I and 7 assigned to group II. There was no correlation between vitamin B12 or folate levels and development of myelosuppression. Vitamin B12 and folinic acid supplementation of ZDV therapy does not seem useful in preventing or reducing ZDV-induced myelotoxicity in the overall treated population, although a beneficial effect in certain subgroups of patients cannot be excluded.