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Severity-Related Changes of Bronchial Microbiome in Chronic Obstructive Pulmonary Disease

ABSTRACT Bronchial colonization by potentially pathogenic microorganisms (PPMs) is often demonstrated in chronic obstructive pulmonary disease (COPD), but culture-based techniques identify only a portion of the bacteria in mucosal surfaces. The aim of the study was to determine changes in the bronchial microbiome of COPD associated with the severity of the disease. The bronchial microbiome of COPD patients was analyzed by 16S rRNA gene amplification and pyrosequencing in sputum samples obtained during stable disease. Seventeen COPD patients were studied (forced expiratory volume in the first second expressed as a percentage of the forced vital capacity [FEV1%] median, 35.0%; interquartile range [IQR], 31.5 to 52.0), providing a mean of 4,493 (standard deviation [SD], 2,598) sequences corresponding to 47 operational taxonomic units (OTUs) (SD, 17) at a 97% identity level. Patients were dichotomized according to their lung function as moderate to severe when their FEV1% values were over the median and as advanced when FEV1% values were lower. The most prevalent phyla in sputum were Proteobacteria (44%) and Firmicutes (16%), followed by Actinobacteria (13%). A greater microbial diversity was found in patients with moderate-to-severe disease, and alpha diversity showed a statistically significant decrease in patients with advanced disease when assessed by Shannon (ρ = 0.528; P = 0.029, Spearman correlation coefficient) and Chao1 (ρ = 0.53; P = 0.028, Spearman correlation coefficient) alpha-diversity indexes. The higher severity that characterizes advanced COPD is paralleled by a decrease in the diversity of the bronchial microbiome, with a loss of part of the resident flora that is replaced by a more restricted microbiota that includes PPMs.

Long-term azithromycin therapy in patients with severe COPD and repeated exacerbations

Background The aim of this study was to determine whether long-term intermittent azithromycin therapy reduces the frequency of exacerbation in severe chronic obstructive pulmonary disease (COPD). Methods We retrospectively investigated the clinical benefits of long-term azithromycin (500 mg orally three times per week) over 12 months in patients with severe COPD and a minimum of four acute exacerbations (AECOPD) per year or chronic bronchial colonization by Pseudomonas aeruginosa, comparing the number of AECOPD, hospitalizations due to respiratory disease, days of hospital stay, and bacterial infections during azithromycin treatment and in the year prior to this therapy. Results Twenty patients who completed the 12-month treatment period were analyzed. No clinically significant adverse events were observed during azithromycin treatment. Compared with baseline data, azithromycin therapy significantly reduced the number of AECOPD (2.8 ± 2.5 versus 6.8 ± 2.8, P < 0.001), hospitalizations (1.4 ± 1.5 versus 3.6 ± 1.4, P < 0.001), and cumulative annual days of hospital stay (25 ± 32.2 versus 43.7 ± 21.4, P = 0.01). The improvement was particularly significant in patients with exacerbations caused by common potentially pathogenic microorganisms, who had 70% fewer AECOPD and hospitalizations. Patients colonized by P. aeruginosa had reductions of 43% in AECOPD and 47% in hospitalizations. Conclusion Long-term azithromycin is well tolerated and associated with significant reductions in AECOPD, hospitalizations, and length of hospital stay in patients with severe COPD.

Pseudomonas aeruginosa isolates in severe chronic obstructive pulmonary disease: characterization and risk factors

BackgroundPatients with severe chronic obstructive pulmonary disease (COPD) are at increased risk of infection by P. aeruginosa. The specific role of bronchiectasis in both infection and chronic colonization by this microorganism in COPD, however, remains ill defined.To evaluate the prevalence and risk factors for P. aeruginosa recovery from sputum in outpatients with severe COPD, characterizing P. aeruginosa isolates by pulsed-field gel electrophoresis (PFGE) and focusing on the influence of bronchiectasis on chronic colonization in these patients.MethodsA case-cohort study of 118 patients with severe COPD attended at a Respiratory Day Unit for an acute infectious exacerbation and followed up over one year. High-resolution CT scans were performed during stability for bronchiectasis assessment and sputum cultures were obtained during exacerbation and stability in all patients. P. aeruginosa isolates were genotyped by PFGE. Determinants of the recovery of P. aeruginosa in sputum and chronic colonization by this microorganism were assessed by multivariate analysis.ResultsP. aeruginosa was isolated from 41 of the 118 patients studied (34.7%). Five of these 41 patients (12.2%) with P. aeruginosa recovery fulfilled criteria for chronic colonization. In the multivariate analysis, the extent of bronchiectasis (OR 9.8, 95% CI: 1.7 to 54.8) and the number of antibiotic courses (OR 1.7, 95% CI: 1.1 to 2.5) were independently associated with an increased risk of P. aeruginosa isolation. Chronic colonization was unrelated to the presence of bronchiectasis (p=0.75). In patients with chronic colonization the isolates of P. aeruginosa retrieved corresponded to the same clones during the follow-up, and most of the multidrug resistant isolates (19/21) were harbored by these patients.ConclusionsThe main risk factors for P. aeruginosa isolation in severe COPD were the extent of bronchiectasis and exposure to antibiotics. Over 10% of these patients fulfilled criteria for chronic colonization by P. aeruginosa and showed clonal persistence, independently of the presence of bronchiectasis.

In vitro effect of three-drug combinations of antituberculous agents against multidrug-resistant Mycobacterium tuberculosis isolates

Multidrug resistance has become a problem in the management of tuberculosis, leading to an urgent need for research related to new regimens including the currently available drugs. The objectives of this study were: (i) to study the effect of the following second-choice three-drug combinations against multidrug-resistant (MDR) and drug-susceptible clinical isolates (levofloxacin, linezolid and ethambutol; levofloxacin, amikacin and ethambutol; and levofloxacin, linezolid and amikacin); and (ii) to compare the effect of these combinations with an isoniazid, rifampicin and ethambutol combination against drug-susceptible clinical isolates. A total of 9 MDR clinical and 12 drug-susceptible isolates (11 clinical isolates and the H37Rv reference strain) were studied using an adaptation of the chequerboard assay. The fractional inhibitory concentration index (FICI) was calculated as follows: FICI=FIC(A)+FIC(B)+FIC(C)=A/MIC(A)+B/MIC(B)+C/MIC(C), where A, B and C are the minimum inhibitory concentrations (MICs) of each antibiotic in combination and MIC(A), MIC(B) and MIC(C) are the individual MICs. The FICI was interpreted as synergism when the value was <0.75. The FICI of all the combinations ranged from 1.5 to 3, showing indifferent activity. No differences were found between MDR and drug-susceptible isolates, or between the second-choice combinations and the fourth combination against drug-susceptible isolates. In conclusion, the second-choice drugs are equally effective as the combination of isoniazid, rifampicin and ethambutol.

In Vitro Susceptibilities of Clinical Yeast Isolates to the New Antifungal Eberconazole Compared with Their Susceptibilities to Clotrimazole and Ketoconazole

ABSTRACT The antifungal activity of eberconazole, a new imidazole derivative, against 124 clinical isolates of Candidacomprising eight different species and to 34 isolates ofCryptococcus neoformans was compared to those of clotrimazole and ketoconazole. MICs of eberconazole, determined by the National Committee for Clinical Laboratory Standards standardized microbroth method, were equal to or lower than those of other azoles, especially for Candida krusei and Candida glabrata, which are usually resistant to triazoles.

The volatile metabolic fingerprint of ventilator-associated pneumonia

Dear Editor, The diagnostic approach for ventilator-associated pneumonia (VAP) needs to be improved [1]. Volatile organic compounds (VOCs), produced either by invading respiratory pathogens or the patient’s pulmonary defense system, could serve as early diagnostic markers for VAP [2]. Electronic nose (eNose) technology integratively captures complex VOC mixtures to create a ‘VOC fingerprint’ using an array of semi-selective sensors [3]. We hypothesized that an eNose would be able to discriminate patients with VAP from those without VAP based on analysis of headspace air from tracheal aspirates (TAs). In a prospective cohort study we collected TAs every third day from 45 intensive care unit (ICU) patients who were ventilated for more than 7 days. Fourteen patients developed VAP, 14 patients had airway colonization but did not develop VAP and 17 patients developed neither VAP nor airway colonization (study methodology and patient characteristics are given in the Electronic Supplementary Material). The eNose was able to accurately discriminate patients with VAP from those without VAP in both a cross-sectional and longitudinal analysis (Fig. 1, upper panels), and the use of a ‘VOC fingerprint’ was found to improve the diagnostic accuracy of the Clinical Pulmonary Infection Score (Fig. 1, lower panels) in this small cohort of patients. Notably, discrimination by the eNose was not affected by airway colonization, and the findings were independent of the number of colony forming units in the TAs. Our study has several limitations. First, we were not able to identify which VOCs differentiate between patients with VAP and those without VAP. Furthermore, this study was performed in a highly selected cohort of patients, and the sample size was rather small, thereby limiting generalization of our findings. Indeed, the results of our study need to be confirmed in robust and larger studies. Of interest, the results of our study suggest that the observed changes in VOC-fingerprints are not solely the result of the presence or absence of bacteria in TAs. VOC-fingerprints can change with the bacterial ecology from colonization to infection, which

Evaluation of the VersaTREK System Compared to the Bactec MGIT 960 System for First-Line Drug Susceptibility Testing of Mycobacterium tuberculosis

ABSTRACT The aim of this study was to evaluate the reliability of the VersaTREK system for Mycobacterium tuberculosis drug susceptibility testing compared with results obtained with the Bactec MGIT 960 system. A total of 67 strains were evaluated. Overall agreement was at 98.5%. Kappa indexes were 1.0 for isoniazid, rifampin, and ethambutol, 0.937 for pyrazinamide, and 0.907 for streptomycin. The VersaTREK system is validated for M. tuberculosis drug susceptibility testing.

Biomarkers kinetics in the assessment of ventilator-associated pneumonia response to antibiotics - results from the BioVAP study

Purpose: Our aim was to evaluate the role of biomarker kinetics in the assessment of ventilator‐associated pneumonia (VAP) response to antibiotics. Materials and methods: We performed a prospective, multicenter, observational study to evaluate in 37 microbiologically documented VAP, the kinetics of C‐reactive protein (CRP), procalcitonin (PCT), mid‐region fragment of pro‐adrenomedullin (MR‐proADM). The kinetics of each variable, from day 1 to 6 of therapy, was assessed with a time dependent analysis comparing survivors and non‐survivors. Results: During the study period kinetics of CRP as well as its relative changes, CRP‐ratio, was significantly different between survivors and non‐survivors (p = 0.026 and p = 0.005, respectively). On day 4 of antibiotic therapy, CRP of survivors was 47% of the initial value while it was 96% in non‐survivors. The kinetics of other studied variables did not distinguish between survivors and non‐survivors. In survivors the bacterial load also decreased markedly. Adequate initial antibiotic therapy was associated with lower mortality (p = 0.025) and faster CRP decrease (p = 0.029). Conclusions: C‐reactive protein kinetics can be used to identify VAP patients with poor outcome as soon as four days after the initiation of treatment. (Trial registration ‐ NCT02078999; registered 3 August 2012). HIGHLIGHTSBiomarkers could be useful in the assessment of VAP response to antibiotics.Among the studied biomarkers CRP and CRP‐ratio showed the best performance.CRP course showed a good correlation with the adequacy of antibiotic therapy.CRP course showed a good correlation with the tracheal bacterial load.

Imported cases of Chikungunya in Barcelona in relation to the current American outbreak

BACKGROUND The Chikungunya virus (CKIKV) is currently present in America. Travel between America and Europe is particularly intense and one of the main vectors of CHIKV, Aedes albopictus, is well established in the Mediterranean basin. We describe a series of imported cases that could originate a European outbreak. METHODS We retrospectively studied cases of CHIKV originating in America and diagnosed in the last year in three Tropical Medicine Units of Barcelona of the International Health Program of the Catalan Health Institute (PROSICS). Clinical, microbiological and epidemiological data were analyzed. RESULTS Forty-two CHIKV cases who had returned from 11 American countries were included. Fever was the most common symptom at onset (96.1%). Three months after symptom onset 50% continued with arthralgias, 35.3% fatigue and 11.8% arthritis. Three patients were viremic at the time of diagnosis by RT-PCR, and the remaining were diagnosed by serology (CHIKV IgM or IgG). Five (11.9%) patients had positive IgM for both dengue virus and CHIKV. CONCLUSIONS The origin of the cases was diverse, the most frequent being initially the Dominican Republic, followed later by Venezuela and Colombia. Symptoms were not severe but persisted, accompanied by unremitting positive IgM. Diagnosis was mainly based on serology and RT-PCR, with the performance of the rapid immunochromatographic test being low. Phylogenetic studies showed that two viremic cases were caused by a strain of Asian lineage with a lower adaptability to Aedes albopictus. Co-infection with the dengue virus was common, but the clinical course was not affected by coinfection. Non-steroidal anti-inflammatory drugs were administered to 71.4% and steroids to 21.4%. The number of imported cases of CHIKV in Spain is rising due to introduction of this virus in America, and this could lead to an autochthonous outbreak if Public Health measures are not taken.

El cribado de las enfermedades parasitarias en la población inmigrante asintomática

Parasitic diseases suppose an important health problem in people from high endemic areas, so these must be discarded properly. Usually, these infections develop asymptomatically but, in propitious situations, are likely to reactivate themselves and can cause clinical symptoms and/or complications in the receiving country. Moreover, in some cases it is possible local transmission. Early diagnosis of these parasitic diseases made by appropriate parasitological techniques and its specific treatment will benefit both, the individual and the community. These techniques must be selected according to geoepidemiological criteria, patients origin, migration route or time spent outside the endemic area; but other factors must also be considered as its sensitivity and specificity, implementation experience and availability. Given the high prevalence of intestinal parasites on asymptomatic immigrants, it is recommended to conduct a study by coproparasitological techniques. Because of its potential severity, the screening of asymptomatic malaria with sensitive techniques such as PCR (polymerase chain reaction) is also advisable. Serological screening for Chagas disease should be performed on all Latin American immigrants, except for people from the Caribbean islands. Other important parasites, which should be excluded, are filariasis and urinary schistosomiasis, by using microscopic examination. The aim of this paper is to review the different techniques for the screening of parasitic diseases and its advices within the care protocols for asymptomatic immigrants.Resumen Las enfermedades parasitarias pueden suponer un importante problema de salud en individuos provenientes de zonas de alta endemicidad, por lo que deben descartarse adecuadamente. Generalmente son asintomaticas, pero en situaciones favorables se pueden reactivar y producir manifestaciones clinicas y/o complicaciones. Aunque no muy frecuentemente, existe tambien la posibilidad de transmision en el pais de acogida. El diagnostico precoz, mediante protocolos de cribado adecuados, permitira un tratamiento especifico que beneficie tanto al individuo como a la comunidad. Estas tecnicas seran seleccionadas segun criterios geoepidemiologicos como el origen del paciente, la ruta migratoria o el tiempo transcurrido fuera del area endemica; pero tambien deben considerarse otros factores como su sensibilidad y especificidad, la experiencia en su implementacion y su disponibilidad. Dada su alta prevalencia y considerando estos criterios, deben descartarse las parasitosis intestinales mediante estudio coproparasitologico. Por su potencial gravedad, es aconsejable el cribado de la malaria utilizando tecnicas muy sensibles como la PCR (reaccion en cadena de la polimerasa). El cribado serologico de la enfermedad de Chagas esta indicado en todos los inmigrantes de origen latinoamericano, excepto en aquellos procedentes de las islas del Caribe. Otras parasitosis importantes, como la filariasis y la esquistosomiasis urinaria, seran descartadas mediante examen microscopico. El objetivo de este trabajo es la revision de las distintas tecnicas de cribado de enfermedades parasitarias y su indicacion dentro de los protocolos de atencion a la poblacion inmigrante asintomatica.