Mycoplasma pneumoniae in Children With and Without Community-acquired Pneumonia. What do PCR and Serology Say?

BACKGROUND: IgM titers of Mycoplasma pneumoniae can remain high for months or years, and specific DNA can be detected in asymptomatic people. METHODS: We compared the performance of serology and PCR in children with and without community-acquired pneumonia (CAP) for the diagnosis of M. pneumoniae. RESULTS: In children with CAP, a positive test by M. pneumoniae (PCR and/or paired serology or both) were found in 13.9%. Of these, 10.3% were positive by multiplex PCR (Seeplex-Seegen), and 6.7% exhibited quadrupled titers (22 for IgG, 6 for IgM and 5 for both). Both tests were positive in 2.8% of cases. In the group without CAP, 3.3% were positive by PCR. Thirty-two percent of children with CAP and 38.3% of healthy children had IgM titers >11 in the acute phase. CONCLUSIONS: The detection of IgM is not useful for diagnosing acute M. pneumoniae infection, and a positive PCR result can be due to colonization and not infection. New and better diagnostic techniques are required.

Inflammatory Cell Differentiation and Chemotaxis and Extracellular Tissue Repair Markers Are Correlated with Pulmonary Dysfunction in HIV Infected Individuals Presenting with Community-Acquired Pneumonia.

Prior studies have shown that HIV patients develop permanent pulmonary dysfunction following an episode of community-acquired pneumonia (CAP). However, the mechanism causing pulmonary dysfunction remains an enigma. HIV patients experience chronic inflammation. We hypothesized that CAP exacerbates inflammation in HIV patients resulting in an accelerated decline in lung function. A prospective cohort pilot study enrolled HIV patients hospitalized in Medellin, Colombia, with a diagnosis of CAP. Sixteen patients were eligible for the study; they were split into 2 groups: HIV and HIV+CAP. Plasma, sputum, and pulmonary function test (PFT) measurements were retrieved within 48 h of hospital admission and at 1 month follow-up. The concentrations of 13 molecules and PFT values were compared between the 2 cohorts. The HIV+CAP group had lower lung function compared to the HIV group; forced vital capacity (FVC)% predicted and forced expiratory volume in 1 s (FEV1)% predicted decreased, while FEV1/FVC remained constant. APRIL, BAFF, CCL3, and TIMP-1 correlated negatively with FVC% predicted and FEV1% predicted; the relationships however were moderate in strength. Furthermore, the concentrations of BAFF, CCL3, and TIMP-1 were statistically significant between the 2 groups (P ≤ 0.05). Our results indicate that HIV patients with CAP have a different inflammatory pattern and lower lung function compared to HIV patients without CAP. BAFF, CCL3, and TIMP-1 were abnormally elevated in HIV patients with CAP. Future studies with larger cohorts are required to verify these results. In addition, further investigation is required to determine if BAFF, CCL3, and TIMP-1 play a role in the process causing pulmonary dysfunction.

[Current characteristics of tuberculosis and human immunodeficiency virus co-infection in a cohort of hospitalized patients in Medellín, Colombia].

INTRODUCTION: Tuberculosis (TB) is an important cause of morbidity and mortality in HIV patients. It is unknown if the advent of molecular diagnostic methods and a greater availability of antiretroviral therapy (ART) in our country have changed some characteristics of the TB/HIV co-infection. OBJECTIVE: To describe the epidemiology, clinical features, diagnosis, resistance patterns, tuberculosis drug effects and mortality in co-infected patients. MATERIALS AND METHODS: Retrospective study based on the review of medical records of hospitalized co-infected adults in a university hospital in Medellín, Colombia. RESULTS: A total of 178 patients was included in the study. TB and HIV diagnosis was simultaneous in 49.4%. In the moment of TB diagnosis, the median CD4 count was 61 cells/µL (27-145). Pulmonary tuberculosis (PTB) occurred in 28% of patients, extrapulmonary (EPTB) in 23%, and mixed TB in 48.9%. The main EPTB affectations were lymphatic (55.4%), gastrointestinal (35.9%), and of the central nervous system (18.7%). Ziehl-Neelsen stain was positive in 137 patients (77%), mycobacterium culture in 121 (68%), and TB-PCR, in 85 of those patients in whom the test was done. Rifampicin resistance was detected in six cases (4.9%). Transaminases (ALT) increased in half of the patients during TB treatment, but only 10% met liver-toxicity criteria. In-hospital mortality was 11.3%. The single risk factor associated with mortality was CD4 count <50/µL (RR=3.9; 95% CI: 1.36-11.37; p=0.01). CONCLUSIONS: When it occurs as an opportunistic infection, TB usually leads to the diagnosis of advanced HIV disease. If used appropriately, TB diagnosis in these patients can be done by conventional methods. It is always necessary to monitor liver function during TB treatment and to rule out drug resistance.

Current characteristics of tuberculosis and human immunodeficiency virus co-infection in a cohort of hospitalized patients in Medellín, Colombia / Características actuales de la coinfección con tuberculosis y el virus de la inmunodeficiencia humana en pacientes hospitalizados en Medellín, Colombia

Introduction: Tuberculosis (TB) is an important cause of morbidity and mortality in HIV patients. It is unknown if the advent of molecular diagnostic methods and a greater availability of antiretroviral therapy (ART) in our country have changed some characteristics of the TB/HIV co-infection. Objective: To describe the epidemiology, clinical features, diagnosis, resistance patterns, tuberculosis drug effects and mortality in co-infected patients. Materials and methods: Retrospective study based on the review of medical records of hospitalized co-infected adults in a university hospital in Medellín, Colombia. Results: A total of 178 patients was included in the study. TB and HIV diagnosis was simultaneous in 49.4%. In the moment of TB diagnosis, the median CD4 count was 61 cells/µL (27-145). Pulmonary tuberculosis (PTB) occurred in 28% of patients, extrapulmonary (EPTB) in 23%, and mixed TB in 48.9%. The main EPTB affectations were lymphatic (55.4%), gastrointestinal (35.9%), and of the central nervous system (18.7%). Ziehl-Neelsen stain was positive in 137 patients (77%), mycobacterium culture in 121 (68%), and TB-PCR, in 85 of those patients in whom the test was done. Rifampicin resistance was detected in six cases (4.9%). Transaminases (ALT) increased in half of the patients during TB treatment, but only 10% met liver-toxicity criteria. In-hospital mortality was 11.3%. The single risk factor associated with mortality was CD4 count <50/µL (RR=3.9; 95% CI: 1.36-11.37; p=0.01). Conclusions: When it occurs as an opportunistic infection, TB usually leads to the diagnosis of advanced HIV disease. If used appropriately, TB diagnosis in these patients can be done by conventional methods. It is always necessary to monitor liver function during TB treatment and to rule out drug resistance.

Introducción. La tuberculosis es una causa importante de morbilidad y mortalidad en pacientes positivos para el HIV. Los métodos de diagnóstico molecular y una mayor disponibilidad del tratamiento antirretroviral en el país pueden haber cambiado las características de la infección concomitante. Objetivo. Describir la epidemiología, las características clínicas, el diagnóstico, los patrones de resistencia, los efectos secundarios de los medicamentos antituberculosos y la mortalidad, en pacientes con las dos infecciones. Materiales y métodos. Se hizo un estudio retrospectivo basado en la revisión de historias clínicas de adultos hospitalizados en un hospital universitario de Medellín, Colombia. Resultados. Se incluyeron 178 pacientes en el estudio. El diagnóstico de tuberculosis e infección por el HIV fue simultáneo en 49,9 %. En el momento del diagnóstico, la mediana de CD4 fue de 61 células/ µL (rango de 27 a 145). La tuberculosis pulmonar ocurrió en 28 % de los pacientes, la extrapulmonar en 23% y la mixta en 48,9%. En la tuberculosis extrapulmonar, el compromiso fue principalmente linfático (55,4 %), gastrointestinal (35,9%) y del sistema nervioso central (18,7 %). La tinción de Ziehl-Neelsen fue positiva en 137 pacientes (77 %), en tanto que el cultivo para micobacterias lo fue en 121 (68 %). La reacción en cadena de la polimerasa para detectar la tuberculosis fue positiva en 85 de los pacientes a quienes se les hizo la prueba. Se detectó resistencia a la rifampicina en seis casos (4,9 %). Al iniciar el tratamiento antituberculoso, las transaminasas se elevaron en la mitad de los pacientes, pero solo 10 % cumplieron los criterios de hepatotoxicidad. La mortalidad hospitalaria fue de 11,3 %. El único factor de riesgo asociado con la mortalidad fue un conteo de CD4 menor de 50/µL (RR=3,9; IC95% 1,36-11,37; p=0,01). Conclusiones. Cuando la tuberculosis se presenta de manera oportunista, comúnmente lleva al diagnóstico de enfermedad avanzada por el HIV. Su diagnóstico en estos pacientes puede hacerse con los métodos convencionales. Es necesario vigilar la función hepática durante el tratamiento y excluir la resistencia a los medicamentos.

Genotyping and macrolide resistance of Mycoplasma pneumoniae identified in children with community-acquired pneumonia in Medellín, Colombia.

OBJECTIVES: The aim of this study was to describe the genotypes and the main characteristics of community-acquired pneumonia (CAP) caused by Mycoplasma pneumoniae in hospitalized children in Medellín and neighboring municipalities during the period 2011-2012. METHODS: The M. pneumoniae genotype was determined by PCR and sequencing of the p1 and 23S rRNA genes from induced sputum samples and nasopharyngeal swabs (NPS). Samples were obtained from children with CAP who were hospitalized in 13 healthcare centers. In addition, a spatio-temporal analysis was performed to identify the potential risk areas and clustering of the cases over time. RESULTS: A variant of type 2 was the dominant genotype in the induced sputum (96.1%) and NPS (89.3%) samples; the type 1 variant was identified in 3.9% and 10.7% of these samples, respectively. No strains with mutations in the 23S rRNA gene associated with macrolide resistance were found. The cases in Medellín were mainly concentrated in the northeastern areas and western districts. However, no temporal relationship was found among these cases. CONCLUSIONS: A variant of type 2 of M. pneumoniae prevailed among children with CAP during the study period. No strains with mutations associated with macrolide resistance were found.

Comparison of serological methods with PCR-based methods for the diagnosis of community-acquired pneumonia caused by atypical bacteria.

BACKGROUND: The diagnosis of community-acquired pneumonia (CAP) caused by Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae is traditionally based on cultures and serology, which have special requirements, are time-consuming, and offer delayed results that limit their clinical usefulness of these techniques. We sought to develop a multiplex PCR (mPCR) method to diagnosis these bacterial infections in CAP patients and to compare the diagnostic yields obtained from mPCR of nasopharyngeal aspirates (NPAs), nasopharyngeal swabs (NPSs), and induced sputum (IS) with those obtained with specific PCR commercial kits, paired serology, and urinary antigen. RESULTS: A total of 225 persons were included. Of these, 10 patients showed serological evidence of L. pneumophila infection, 30 of M. pneumoniae, and 18 of C. pneumoniae; 20 individuals showed no CAP. The sensitivities were mPCR-NPS = 23.1%, mPCR-IS = 57.1%, Seeplex®-IS = 52.4%, and Speed-oligo®-NPA/NPS = 11.1%, and the specificities were mPCR-NPS = 97.1%, mPCR-IS = 77.8%, Seeplex®-IS = 92.6%, and Speed-oligo®-NPA/NPS = 96.1%. The concordance between tests was poor (kappa <0.4), except for the concordance between mPCR and the commercial kit in IS (0.67). In individuals with no evidence of CAP, positive reactions were observed in paired serology and in all PCRs. CONCLUSIONS: All PCRs had good specificity but low sensitivity in nasopharyngeal samples. The sensitivity of mPCR and Seeplex® in IS was approximately 60%; thus, better diagnostic techniques for these three bacteria are required.

[Microscopic diagnosis of Pneumocystis jirovecii pneumonia in bronchoalveolar lavage and oropharyngeal wash samples of immunocompromised patients with pneumonia]. / Diagnóstico microscópico de neumonía por Pneumocystis jirovecii en muestras de lavado broncoalveolar y lavado orofaríngeo de pacientes inmunocomprometidos con neumonía.

INTRODUCTION: The diagnosis of Pneumocystis jirovecii pneumonia is based on observation of the microorganism using several staining techniques in respiratory samples, especially bronchoalveolar lavage and induced sputum. Recently, the fungus also has been detected in oropharyngeal wash samples, but only using molecular tests. OBJECTIVE: The diagnostic yield of two microscopic stains, toluidine blue O and direct fluorescent antibody, was compared in bronchoalveolar lavage and oropharyngeal wash samples for the detection of P. jirovecii in immunocompromised patients with pneumonia. MATERIALS AND METHODS: Cross-sectional evaluation diagnostic tests were used in 166 immunosuppressed patients with suspected P. jirovecii. By protocol, bronchoscopic bronchoalveolar lavage and oropharyngeal wash samples were prepared by cytocentrifugation, and slides were stained with toluidine blue and fluorescent antibody. The proportion of positive results from each stain and concordance between them were determined. RESULTS: Twenty-four cases (14.5%) of P. jirovecii were detected in bronchoalveolar lavage samples. Of them, 21 were positive by both toluidine blue and fluorescent antibody stains, whereas 3 cases were detected by fluorescent antibody alone. None of the 166 oropharyngeal wash samples were positive by either of these techniques. No significant differences were found between proportions from positive results (p=0.63). Concordance (kappa coefficient) between both stains was 0.92 (95% CI: 0.84-1.00). CONCLUSIONS: Both techniques were useful to diagnose P. jirovecii in bronchoalveolar lavage samples. However, toluidine blue stain did not detect 12% of fluorescent antibody positive cases. Oropharyngeal wash samples do not provide sufficient material for the microscopic identification of this fungus.

Reading and interpretation of chest X-ray in adults with community-acquired pneumonia

INTRODUCTION: Traditional reading of chest X-rays usually has a low prognostic value and poor agreement. OBJECTIVE: This study aimed to determine the interobserver and intraobserver agreement using two reading formats in patients with community-acquired pneumonia, and to explore their association with etiology and clinical outcomes. METHODS: A pulmonologist and a radiologist, who were blind to clinical data, interpreted 211 radiographs using a traditional analysis format (type and location of pulmonary infiltrates and pleural findings), and a quantitative analysis (pulmonary damage categorized from 0 to 10). For both, the interobserver and intraobserver agreement was estimated (Kappa statistic and intraclass correlation coefficient). The latter was assessed in a subsample of 25 radiographs three months after the initial reading. Finally, the observers made a joint reading to explore its prognostic usefulness via multivariate analysis. RESULTS: Seventy-four chest radiographs were discarded due to poor quality. With the traditional reading, the mean interobserver agreement was moderate (0.43). It was considered good when the presence of pleural effusion, and the location of the infiltrates in the right upper lobe and both lower lobes, were evaluated; moderate for multilobar pneumonia; and poor for the type of infiltrates. The mean intraobserver agreement for each reviewer was 0.71 and 0.5 respectively. The quantitative reading had an agreement between good and excellent (interobserver 0.72, intraobserver 0.85 and 0.61). Radiological findings were neither associated to a specific pathogen nor to mortality. CONCLUSION: In patients with pneumonia, the interpretation of the chest X-ray, especially the smallest of details, depends solely on the reader.

Diagnóstico microscópico de neumonía por Pneumocystis jirovecii en muestras de lavado broncoalveolar y lavado orofaríngeo de pacientes inmunocomprometidos con neumoníA / Microscopic diagnosis of Pneumocystis jirovecii pneumonia in bronchoalveolar lavage and oropharyngeal wash samples of immunocompromised patients with pneumonia

Introducción. El diagnóstico de neumonía por Pneumocystis jirovecii se fundamenta en la visualización microscópica del hongo en secreciones respiratorias. Técnicas moleculares recientes también lo han detectado en muestras de orofaringe, pero su utilidad diagnóstica es discutible. En Colombia, hay poca información al respecto. Objetivo. Comparar el rendimiento de dos coloraciones, azul de toluidina O e inmunofluorescencia directa, en muestras de lavado broncoalveolar y lavado orofaríngeo en pacientes inmunocomprometidos con neumonía. Materiales y métodos. Se llevó a cabo un estudio transversal de evaluación de pruebas diagnósticas en 166 pacientes inmunocomprometidos con sospecha de neumonía por P. jirovecii. Por protocolo, las muestras de lavado broncoalveolar y orofaríngeo se citocentrifugaron y se colorearon con azul de toluidina e inmunofluorescencia. Se determinó la proporción de resultados positivos con ambas tinciones en cada una de las muestras, y la concordancia entre ellas. Resultados. Se detectaron 24 casos de neumonía por P. jirovecii en las muestras de lavado broncoalveolar (14,5 %), 21 de los cuales fueron positivos por ambas pruebas, mientras que tres casos se detectaron sólo por inmunofluorescencia. Ninguna de las 166 muestras de lavado orofaríngeo fue positiva por cualquiera de estas técnicas. Al comparar las proporciones de resultados positivos, no se encontraron desacuerdos significativos (p=0,63). La concordancia (coeficiente kappa) entre ellas fue de 0,92 (IC95%: 0,84-1). Conclusiones. Ambas coloraciones son útiles para diagnosticar neumonía por P. jirovecii en muestras de lavado broncoalveolar. Sin embargo, el azul de toluidina no detecta, aproximadamente, el 12 % de los casos positivos por inmunofluorescencia. Las muestras de lavado orofaríngeo no son apropiadas para detectar microscópicamente P. jirovecii.

Introduction. The diagnosis of Pneumocystis jirovecii pneumonia is based on observation of the microorganism using several staining techniques in respiratory samples, especially bronchoalveolar lavage and induced sputum. Recently, the fungus also has been detected in oropharyngeal wash samples, but only using molecular tests. Objective. The diagnostic yield of two microscopic stains, toluidine blue O and direct fluorescent antibody, was compared in bronchoalveolar lavage and oropharyngeal wash samples for the detection of P. jirovecii in immunocompromised patients with pneumonia. Materials and methods. Cross-sectional evaluation diagnostic tests were used in 166 immunossupressed patients with suspected P. jirovecii. By protocol, bronchoscopic bronchoalveolar lavage and oropharyngeal wash samples were prepared by cytocentrifugation, and slides were stained with toluidine blue and fluorescent antibody. The proportion of positive results from each stain and concordance between them were determined. Results. Twenty-four cases (14.5%) of P. jirovecii were detected in bronchoalveolar lavage samples. Of them, 21 were positive by both toluidine blue and fluorescent antibody stains, whereas 3 cases were detected by fluorescent antibody alone. None of the 166 oropharyngeal wash samples were positive by either of these techniques. No significant differences were found between proportions from positive results (p=0.63). Concordance (kappa coefficient) between both stains was 0.92 (95% CI: 0.84-1.00). Conclusions. Both techniques were useful to diagnose P. jirovecii in bronchoalveolar lavage samples. However, toluidine blue stain did not detect 12% of fluorescent antibody positive cases. Oropharyngeal wash samples do not provide sufficient material for the microscopic identification of this fungus.

Reading and interpretation of chest X-ray in adults with community-acquired pneumonia.

INTRODUCTION: Traditional reading of chest X-rays usually has a low prognostic value and poor agreement. OBJECTIVE: This study aimed to determine the interobserver and intraobserver agreement using two reading formats in patients with community-acquired pneumonia, and to explore their association with etiology and clinical outcomes. METHODS: A pulmonologist and a radiologist, who were blind to clinical data, interpreted 211 radiographs using a traditional analysis format (type and location of pulmonary infiltrates and pleural findings), and a quantitative analysis (pulmonary damage categorized from 0 to 10). For both, the interobserver and intraobserver agreement was estimated (Kappa statistic and intraclass correlation coefficient). The latter was assessed in a subsample of 25 radiographs three months after the initial reading. Finally, the observers made a joint reading to explore its prognostic usefulness via multivariate analysis. RESULTS: Seventy-four chest radiographs were discarded due to poor quality. With the traditional reading, the mean interobserver agreement was moderate (0.43). It was considered good when the presence of pleural effusion, and the location of the infiltrates in the right upper lobe and both lower lobes, were evaluated; moderate for multilobar pneumonia; and poor for the type of infiltrates. The mean intraobserver agreement for each reviewer was 0.71 and 0.5 respectively. The quantitative reading had an agreement between good and excellent (interobserver 0.72, intraobserver 0.85 and 0.61). Radiological findings were neither associated to a specific pathogen nor to mortality. CONCLUSION: In patients with pneumonia, the interpretation of the chest X-ray, especially the smallest of details, depends solely on the reader.

Histoplasmosis en pacientes con sida: Un estudio de cohorte en Medellín, Colombia / Histoplasmosis in AIDS patients: A cohort study in Medellín, Colombia

Introducción: la histoplasmosis es una micosis endémica en nuestro país y una complicación relativamente frecuente de los pacientes con sida. El objetivo del estudio era identificar las características clínicas, epidemiológicas y los factores de riesgo asociados a la mortalidad en pacientes con sida coinfectados con histoplasmosis. Materiales y métodos: se realizó un estudio de cohorte retrospectivo en el Hospital Universitario San Vicente de Paúl, en Medellín, con 1177 pacientes con VIH atendidos en un programa especializado de sida. Se identificaron los pacientes con histoplasmosis confirmada por aislamiento del hongo, o identificaci&oacut compatibles con Histoplasma capsulatum, mediante microscopía. Se analizaron variables demográficas, clínicas, de laboratorio, comorbilidad, tratamiento recibido y mortalidad. Resultados: La histoplasmosis afectó a 44 de 709 pacientes con sida (6,2%). Entre éstos, el 95,4% tuvo fiebre, el 54,5% enfermedad diseminada e;n de levaduras intracelulares y el 61,3% compromiso pulmonar. El cultivo fue positivo en el 89,3% y la histopatología en el 93,3%. Se encontró tuberculosis concomitante en el 15,9% y neumocistosis en el 11,4%. La mortalidad fue del 22,7%. El riesgo de morir fue mayor en pacientes con formas diseminadas (todas las muertes ocurrieron en sujetos con este tipo de compromiso), disnea (RR 13; IC95% 1,8-93,8), hipotensión (RR 4,5; IC95% 1,6-13,1), deshidrogenasa láctica (DHL) >2 veces (RR 5,2; IC95% 1,2-22,5), y fue menor en quienes recibieron Anfotericina B (RR 0,3; IC95% 0,1-0,8). Discusión: en la región, la histoplasmosis es frecuente en pacientes con sida, y el rendimiento diagnóstico de las técnicas de rutina para H. capsulatum es alto, por lo que deben solicitarse en cualquier caso compatible. Demostrar la comorbilidad sida-histoplasmosis no descarta otras infecciones oportunistas. Los pacientes con formas diseminadas, disnea, hipotensión y DHL alta tienen mayor riesgo de muerte. El tratamiento con anfotericina B se asoció con una mayor sobrevida.

Introduction: histoplasmosis is an endemic mycosis in Colombia and a relatively common complication in HIV patients. The aim of this study was to identify clinical and epidemiological characteristics and mortality risk factors in patients infected with histoplasmosis and HIV. Materials and methods: a retrospective cohort study was carried out at Hospital Universitario San Vicente de Paúl in Medellín with 1177 HIVpositive patients. Patients with histoplasmosis were confirmed by isolation of Histoplasma capsulatum from culture or by identification of intracellular yeasts through microscopy. Data collected from patients included demographic and clinical variables, laboratory values, treatment, and survival. Results: histoplasmosis affected 44/709 patients with AIDS (6.2%). Out of those, 95.4% had fever, 54.5% disseminated illness, and 61.3% pulmonary disease. Culture was positive in 89.3%, and histopathology in 93.3%. Concomitant tuberculosis and Pneumocystis jirovecii infection were diagnosed in 15.9% and 11.4%, respectively. General mortality was 22.7%. Mortality was higher in patients with disseminated forms (all 10 deaths occurred in this fashion), dyspnea (RR 13; 95% CI 1.8-93.8), hypotension (RR 4.5; 95% CI 1.6-13.1), lactate dehydrogenase >2 times the upper limit of the normal range (RR 5.2; 95% CI 1.2-22.5), and it was lower among patients treated with amphotericine B (RR 0.3; 95% CI 0.1-0.8). Discusion: histoplasmosis is frequent in AIDS patients in the region. As the diagnosis yield of routine techniques to identify H. capsulatum is high, they must be required in any compatible setting. Many patients with AIDS-histoplasmosis co-infection acquire other opportunistic infections. Patients with disseminated forms, dyspnea, hypotension, and high levels of DHL have a higher mortality risk. Exposure to amphotericine B is associated with longer survival.

Evaluación de la concordancia entre dos métodos de lavado broncoalveolar para el diagnóstico microbiológico de la neumonía en pacientes con asistencia respiratoria mecánica / Concordance between two methods of bronchoalveolar lavage for the microbiological diagnosis of pneumonia in mechanically ventilated patients

Introducción. El diagnóstico microbiológico de la neumonía permite optimizar el uso de antibióticos en pacientes con asistencia respiratoria mecánica. Para ello se han cultivado cuantitativamente las muestras del lavado broncoalveolar broncoscópico, procedimiento que no siempre es posible. Objetivo. Evaluar la concordancia microbiológica entre muestras respiratorias tomadas porlavado broncoalveolar broncoscópico y no broncoscópico, y establecer si el uso previo de antibióticos y el momento de presentación de la neumonía pueden afectarla. Materiales y métodos. Estudio prospectivo realizado en el Hospital Universitario San Vicente de Paúl, en 38 pacientes con sospecha de neumonía y con asistencia respiratoria mecánica. En todos se practicó el lavado broncoalveolar por fibrobroncoscopia y el lavado nobroncoscópico usando un catéter telescopado de punta preformada (Balcatho). Todas las muestras fueron procesadas siguiendo protocolos microbiológicos convencionales. Resultados. Considerando el lavado broncoalveolar por fibrobroncoscopia como patrón dereferencia, los cultivos permitieron identificar el agente en 60,5 por ciento de los casos. El acuerdo diagnóstico se logró en 82 por ciento de los pacientes y 79 por ciento de los aislamientos. Utilizando el índice kappa de Cohen, la concordancia general entre los dos métodos fue 0,76 [0,60-0,93]; pero en quienes habían recibido antibióticos previos fue 0,26 [0,05-0,48], versus 1,0 en quienes no lo habían hecho (p<0,0001). La concordancia no difirió significativamente cuando se compararon los casos de neumonía temprana y tardía. Conclusiones. La concordancia general entre los dos métodos de lavado broncoalveolar es buena en pacientes con neumonía y respiración asistida mecánicamente. Sin embargo, el uso previo de antibióticos y no el momento de aparición de la neumonía, disminuye ésta significativamente.

[Concordance between two methods of bronchoalveolar lavage for the microbiological diagnosis of pneumonia in mechanically ventilated patients]. / Evaluación de la concordancia entre dos métodos de lavado broncoalveolar para el diagnóstico microbiológico de la neumonía en pacientes con asistencia respiratoria mecánica.

INTRODUCTION: Microbiological diagnosis of pneumonia allows the optimal use of antibiotics in mechanically ventilated patients. That is why samples of bronchoscopic bronchoalveolar lavage had been quantitatively cultivated, but this procedure is not always possible. OBJECTIVE: To evaluate the microbiological concordance between respiratory samples obtained by non-bronchoscopic protected bronchoalveolar lavage compared to the bronchoscopic ones, and to find out whether concordance was affected by previous use of antibiotics or the time of pneumonia onset. MATERIALS AND METHODS: Prospective study conducted at Hospital Universitario San Vicente de Paúl, in 38 patients with suspected pneumonia in mechanical ventilation. Bronchoalveolar lavage specimens were taken by two methods, the traditional one and non-bronchoscopic bronchoalveolar lavage, using a telescoping preformed tip catheter (Balcath). All samples were processed using conventional microbiologic protocols. RESULTS: Considering flexible bronchoscopy with bronchoalveolar lavage as the gold standard, cultures allowed the identification of at least one respiratory pathogen in 60.5% of cases. Diagnostic agreement was achieved in 82% of patients and 79% of microbiologic isolates. Using the Cohen's kappa coefficient, general concordance between both methods was 0.76 [0.60-0.93]; but in those who received previously antibiotics was 0.26 [0.05-0.48], versus 1.0 in those who did not (p<0.0001). Concordance did not differ significantly when cases of early or late pneumonia were compared. CONCLUSIONS: Concordance between non-bronchoscopic and bronchoscopic bronchoalveolar lavage is good in mechanically ventilated patients with pneumonia. However, the use of antibiotics previously, but not the time of pneumonia presentation, significantly decreases that concordance.