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Emilio Bouza

Publications and source records attributed to Emilio Bouza.

At least 55 records · Page 3Linked to original sources
PubMed2004

Rapid direct detection of multiple rifampin and isoniazid resistance mutations in Mycobacterium tuberculosis in respiratory samples by real-time PCR.

Rapid detection of resistance in Mycobacterium tuberculosis can optimize the efficacy of antituberculous therapy and control the transmission of resistant M. tuberculosis strains. Real-time PCR has minimized the time required to obtain the susceptibility pattern of M. tuberculosis strains, but little effort has been made to adapt this rapid technique to the direct detection of resistance from clinical samples. In this study, we adapted and evaluated a real-time PCR design for direct detection of resistance mutations in clinical respiratory samples. The real-time PCR was evaluated with (i) 11 clinical respiratory samples harboring bacilli resistant to isoniazid (INH) and/or rifampin (RIF), (ii) 10 culture-negative sputa spiked with a set of strains encoding 14 different resistance mutations in 10 independent codons, and (iii) 16 sputa harboring susceptible strains. The results obtained with this real-time PCR design completely agreed with DNA sequencing data. In all sputa harboring resistant M. tuberculosis strains, the mutation encoding resistance was successfully detected. No mutation was detected in any of the susceptible sputa. The test was applied only to smear-positive specimens and succeeded in detecting a bacterial load equivalent to 10(3) CFU/ml in sputum samples (10 acid-fast bacilli/line). The analytical specificity of this method was proved with a set of 14 different non-M. tuberculosis bacteria. This real-time PCR design is an adequate method for the specific and rapid detection of RIF and INH resistance in smear-positive clinical respiratory samples.

Antibiotics, Antitubercular↗
PubMed2004

Analysis of clonal composition of Mycobacterium tuberculosis isolates in primary infections in children.

The assumption that Mycobacterium tuberculosis infections should be considered clonally homogeneous has been weakened in the last few years. Recent studies have shown (i) the isolation of different M. tuberculosis strains from sequential episodes, (ii) mixed infections by two M. tuberculosis strains, and (iii) genetic variations in M. tuberculosis subpopulations due to microevolution events. Nevertheless, it is unknown whether clonal heterogeneity could be found in the initial steps of M. tuberculosis infection, i.e., the primary infection. In the present study we analyzed the clonal composition of the M. tuberculosis isolates causing primary infections in children. Cultures were clonally homogeneous in most cases (11 of 12). In 1 of the 12 cases (8.3%), clonal heterogeneity among the M. tuberculosis isolates was found by spoligotyping and IS6110-based restriction fragment length polymorphism analysis. This case occurred in a 2-year-old child in whom microevolution events were unlikely and who had no risk factors for overexposure to M. tuberculosis. Clonal heterogeneity should also be considered in primary M. tuberculosis infections, including circumstances in which it is usually unexpected.

Adolescent↗
PubMed2003

The isolation of Aspergillus fumigatus from respiratory tract specimens in heart transplant recipients is highly predictive of invasive aspergillosis.

BACKGROUND: Prompt recognition of invasive pulmonary aspergillosis (IPA) after heart transplantation is essential for achieving a successful outcome. However, the significance of the isolation of from respiratory specimens in heart transplant recipients is not established. METHODS: From 1990 to 1999, we analyzed first respiratory specimens with spp. growth from heart transplant patients in our institution. All specimens were cultured in both fungal and conventional media. Diagnosis of proven and probable IPA or colonization was made according to criteria of the Mycoses Study Group. RESULTS: During the 10-year study period, spp. was recovered from 30 episodes from 27 heart transplant recipients (incidence: 10.5%). Three episodes were classified as indeterminate and were included in the analysis in a double way, first considering them as true positives and afterward as true negatives, so ranges were obtained. After applying diagnostic criteria, 18 of 30 episodes were proven or probable IPA, and 9 episodes were colonizations. Accordingly, 7 to 8% of heart transplant recipients suffered an IPA, and the overall positive predictive value (PPV) was 60% to 70%. When analyzed by species, the PPV of recovering was 78% to 91%, whereas it was 0% for other species. The PPV increased to 88% to 100% when was recovered from a respiratory specimen other than sputum and decreased to 50% to 67% when it was recovered from sputum. The sensitivities of fungal and conventional media for the recovery of spp. were 95% to 100% and 33% to 38%, respectively. CONCLUSION: The isolation of from the respiratory tract of a heart transplant recipient is highly predictive of invasive aspergillosis.

Aspergillosis, Allergic Bronchopulmonary↗
PubMed2003

Polyclonal and compartmentalized infection by Mycobacterium tuberculosis in patients with both respiratory and extrarespiratory involvement.

Infection by Mycobacterium tuberculosis (MTB) is assumed to be caused by a single strain, and several MTB strains within the same patient are rarely considered. The present study analyzes the phenomenon of mixed infections by MTB in a group of 50 patients with both respiratory and extrarespiratory tuberculosis. First, the proportion of patients with infection by >1 strain was defined, and second, the clonal composition of the MTB populations at different infected sites was studied. In 3 (6%) of 50 patients, >1 strain was cultured, which indicates that mixed infections are not anecdotal. The coinfecting strains were not equally distributed at the respiratory and extrarespiratory site, which reflects a compartmentalization of the infection. In 1 patient, although 2 strains were found at the respiratory site, only 1 of these strains was involved in the extrarespiratory infection, which suggests that clonal selection can occur in the dissemination of the infection.

Bacterial Typing Techniques↗
PubMed2003

Ventilator-associated pneumonia after heart surgery: a prospective analysis and the value of surveillance.

OBJECTIVE: To determine the frequency, etiology, and risk factors of ventilator-associated pneumonia (VAP) and purulent tracheobronchitis (TBX) in patients who have undergone heart surgery. To study the predictive role of systematic surveillance cultures. DESIGN: Prospective study. SETTING: Heart surgery intensive care unit. PATIENTS: Intubated heart surgical patients. INTERVENTIONS: Systematic tracheal aspirate and protected brush catheter cultures of all intubated patients. MEASUREMENTS AND MAIN RESULTS: Studied were the frequency of lower respiratory tract infection in ventilated patients and the role of surveillance cultures. The frequency of VAP was 7.87% (34.5 per 1,000 days of mechanical ventilation), and the criteria for purulent tracheobronchitis was fulfilled by 8.15% of patients (31.13 per 1,000 days of mechanical ventilation). After multivariate analysis, the variables independently associated with the development of respiratory tract infection were central nervous system disorder (relative risk [RR] = 4.7), ulcer disease (RR = 3.6), New York Heart Association score >/=3 (RR = 4), need for mechanical circulatory support (RR = 6.8), duration of mechanical ventilation >96 hrs (RR = 12.3), and reintubation (RR = 63.7). Mortality in our study was as follows: VAP patients, 57.1%; purulent tracheobronchitis patients, 20.7%; colonized patients, 11.5%; and noncolonized patients, 1.6%. Regular surveillance cultures were taken from all ventilated patients to assess the anticipative value of the cultures in predicting respiratory tract infection. A total of 1,626 respiratory surveillance samples were obtained. Surveillance cultures effectively predicted only one episode of VAP and one of tracheobronchitis. CONCLUSIONS: Patients undergoing heart surgery have a high frequency of VAP. VAP is associated with a poor prognosis. In this study, surveillance cultures failed as an anticipative diagnostic method.

Aged↗
PubMed2003

In vitro activities of linezolid against clinical isolates of Mycobacterium tuberculosis that are susceptible or resistant to first-line antituberculous drugs.

We evaluated 117 isolates of Mycobacterium tuberculosis for susceptibility to linezolid by the proportion and E-test methods. Linezolid showed high in vitro activity, with all the strains inhibited by <or=1 microg of the drug per ml. E-test MICs were at least 4 dilutions lower than their equivalents by the standard proportion method.

Acetamides↗
PubMed2003

In vitro activities of tigecycline (GAR-936) and 12 other antimicrobial agents against 90 Eikenella corrodens clinical isolates.

The activity of tigecycline was compared with those of other antimicrobials against 90 isolates of Eikenella corrodens. The MIC at which 90% of the isolates were inhibited was 2 micro g/ml for tigecycline and 1, </=0.5/0.25, 0.5, </=0.12, </=2, and 0.5 micro g/ml for ampicillin, amoxicillin-clavulanate, cefotaxime, imipenem, chloramphenicol, and ciprofloxacin, respectively.

Anti-Bacterial Agents↗
PubMed2003

Increased incidence of pneumococcal bloodstream infections.

Pneumococcal bloodstream infections in pediatric patients rose from 3.6 to 14.8 episodes per 100,000 from 1986 to the year 2000 (P < 0.001) in a population of approximately 650,000 inhabitants (16% <16 years of age). Incidence in the group <24 months of age increased from 7.4 to 78.6 episodes per 100,000 per year (P < 0.001). Overall 75% of the serogroups are included in the new heptavalent vaccine.

Adolescent↗
PubMed2002

Tuberculosis recurrences: reinfection plays a role in a population whose clinical/epidemiological characteristics do not favor reinfection.

BACKGROUND: Tuberculosis (TB) recurrences can be due to either reactivation by the same strain (standard assumption) or reinfection by a new strain. Reinfection has mainly been studied in selected populations with a high risk of reexposure to TB. Our aim was to analyze the role of reinfection in TB recurrences in unselected populations, without the clinical/epidemiological circumstances that favor the involvement of a new different strain of Mycobacterium tuberculosis in the recurrence. METHODS: A molecular typing analysis was performed with 92 sequential isolates of M tuberculosis from 43 patients with recurrent TB, during a 12-year period. The subjects were both positive and negative for the human immunodeficiency virus, most did not adhere to anti-TB therapy, and they lived in an area with a moderate incidence of TB. Recurrence was considered as being caused by reinfection when the molecular fingerprints for the strains involved in the sequential episodes of TB were different. RESULTS: In 14 (33%) of the 43 patients, different M tuberculosis strains were involved in the first and in subsequent episodes of TB. Reinfection was found for patients who were both positive and negative for the human immunodeficiency virus, and most patients did not adhere to anti-TB therapy. Differences between the reinfection and reactivation groups were not significant (P =.77) according to the time interval between episodes. CONCLUSIONS: Reinfection plays an important role in recurrent TB in a population without the clinical/epidemiological circumstances that are usually assumed to favor it. Reinfection should, thus, be considered as a cause of TB recurrences in a wider context than before.

Adult↗
PubMed2002

JC virus load in progressive multifocal leukoencephalopathy: analysis of the correlation between the viral burden in cerebrospinal fluid, patient survival, and the volume of neurological lesions.

JC virus (JCV) is the causative agent of progressive multifocal leukoencephalopathy (PML), a demyelinating central nervous system infection that mainly affects patients with acquired immunodeficiency syndrome. The diagnostic value of the detection of JCV DNA in cerebrospinal fluid (CSF) has been proved. A correlation between the JCV burden in CSF and the PML prognosis has been proposed. To our knowledge, the present study is the first to examine JCV burden in CSF in relation to the magnitude of neurological damage. An in-house quantitative polymerase chain reaction assay was used for measurement of the JCV burden in CSF samples from 12 patients with PML. A wide variation in JCV load (6.4 log) was found among the patient CSF samples, a finding that makes JCV load measurements worthwhile. Virus load values of >4.68 log were associated with shorter patient survival time. No correlation was found between the virus load values and the global volume of brain tissue damaged. Our data suggest that factors other than the volume of neurological lesions influence the shedding of JCV in the CSF.

Adult↗
PubMed2002

Frequency and clinical significance of bloodstream infections caused by C albicans strains with reduced susceptibility to fluconazole.

Reduced susceptibility to fluconazole (RSF) is relatively common in non-albicans Candida isolates and in Candida albicans recovered from HIV-infected patients with relapsing Candida stomatitis or esophagitis. However, little clinical data on bloodstream infections caused by C. albicans with RSF is available. We analyzed 116 episodes of C. albicans fungemia detected over an 11-year period. Four patients (3.4%) had a blood isolate of C. albicans with RSF. Fluconazole MICs were 16 (3 SDD strains) and 128 microg/ml (1 resistant strain), respectively. Three of the patients were HIV (+) and the fourth was a liver transplant recipient. All of them had been previously treated with an azole compound. The liver recipient had breakthrough fungemia while being treated with 400 mg of preemptive fluconazole despite having an MIC of 16 microg/ml. Fluconazole clinical failure was documented in two of the remaining three cases. Only five other patients with C. albicans fungemia caused by fluconazole-resistant strains (>or=64 microg/ml) are described in the literature. Candida albicans fungemia produced by strains with RSF is still uncommon. It should be suspected in patients previously treated with azole agents or with breakthrough fungemia. In our experience, fluconazole remains a safe option for the treatment of most C. albicans fungemias, although surveillance seems advisable.

Antifungal Agents↗
PubMed2002

Extra-abdominal infections due to Gemella species.

OBJECTIVES: To understand the role of Gemella species as a pathogen causing extra-abdominal infections in the Hospital General Universitario Gregorio Marañón. MATERIALS AND METHODS: Between 1994 and 1998, one or more isolates of Gemella sp. were found in 128 patients. The 113 patients with isolates from nonsignificant specimens or representing intra-abdominal infections were excluded. The clinical records of the remaining 15 patients were reviewed as well as the more recent literature. RESULTS: Mean age of patients was 41 years. The underlying conditions most frequently noted were intravenous drug users (n=6; 3 positive for human immunodeficiency virus), alcoholism (n=2), cardiovascular disease (n=2), chronic lung disease (n=2), diabetes (n=1), kidney transplant (n=1). The extra-abdominal infections were skin and soft tissue abscess (n=5), empyema (n=4), brain abscess (n=2), primary bacteremia (n=1), lung abscess (n=1), septic thrombophlebitis (n=1), complicated urinary tract infection (n=1). The infection was monomicrobial in six and polymicrobial in nine cases. Surgical drainage and betalactam antibiotics were used. The outcome was favorable in almost all cases. CONCLUSIONS: Gemella sp. should be included as a cause of localized soft-tissue abscesses, empyema, and bloodstream infection. No case of infective endocarditis was found. Although it is susceptible to several antibiotics, Gemella sp. requires a careful microbiologic diagnosis and a subtle clinical interpretation.

Abscess↗
PubMed2002

Klebsiella and enterobacter: antibiotic resistance and treatment implications.

KLEBSIELLA: spp. and Enterobacter spp. are widespread throughout the environment and also carried by humans. Both genera are well-recognized community and nosocomial pathogens and cause significant infections. They are a common cause of respiratory and nonrespiratory infections. Klebsiella spp. is responsible for 1% to 5% of all cases of community-acquired pneumonia and between 0% to 23% of those acquired in the hospital, and its frequency is greater in alcoholic patients. The majority of cases are unilateral in the posterior segment of the right upper lobe. Lung abscess can occur after a pneumonic process or secondarily to Klebsiella spp. infections and have high rates of morbidity and mortality. K. pneumoniae is one of the most common microorganisms responsible for empyema. Klebsiella spp. and Enterobacter spp. rank fourth and third, respectively, as causes of hospital-acquired pneumonia mainly in patients during the early period of mechanical ventilation. Klebsiella spp. are intrinsically resistant to penicillins and can acquire resistance to third- and fourth-generation cephalosporins owing to the production of plasmid-mediated extended-spectrum beta-lactamases (ESBLs). These plasmids frequently carry aminoglycoside-modifying enzymes. Enterobacter spp. are intrinsically resistant to ampicillin, amoxicillin, amoxicillin-clavulanate, first-generation cephalosporins, and cefoxitin owing to the production of constitutive AmpC beta-lactamase. The derepression of this enzyme is increasingly frequent among clinical isolates and confers resistance to third-generation cephalosporins, and ureido- and carboxypenicillins; fourth-generation cephalosporins retain reasonable activity against depressed strains. Most isolates of Klebsiella spp. and Enterobacter spp. are susceptible to fluoroquinolones, trimethoprimsulfamethoxazole, aminoglycosides, and carbapenems. In some instances, treatment of severe infections caused by these microorganisms may benefit from the combination of beta-lactams (or fluoroquinolones) with aminoglycosides. Because of the high risk for developing resistance during treatment, all severe infections should be carefully watched during therapy.

Anti-Bacterial Agents↗
PubMed2002

Use of anaerobically incubated media to increase yield of positive blood cultures in children.

During a 3-year period we received 10024 blood samples for culture from pediatric patients. Overall 181 episodes of significant bacteremia were documented. During the study period we would have missed 35 (19%) of all significant episodes of pediatric bloodstream infections if we had not been using the anaerobically incubated blood bottle. Anaerobically incubated blood samples are also necessary in the pediatric population.

Adolescent↗
PubMed2002

New real-time PCR able to detect in a single tube multiple rifampin resistance mutations and high-level isoniazid resistance mutations in Mycobacterium tuberculosis.

The emergence of resistance to antituberculosis drugs is a relevant matter worldwide, but the retrieval of antibiograms for Mycobacterium tuberculosis is severely delayed when phenotypic methods are used. Genotypic methods allow earlier detection of resistance, although conventional approaches are cumbersome or lack sensitivity or specificity. We aimed to design a new real-time PCR method to detect rifampin (RIF)- and isoniazid (INH)-resistant M. tuberculosis strains in a single reaction tube. First, we characterized the resistant isolates in our area of Spain by DNA sequencing. Some mutation was found within the rpoB core region in all the RIF-resistant (RIF(r)) strains. Forty-six percent of the INH-resistant (INH(r)) strains showed a mutation in katG codon 315, and most of these were associated with high MICs. Eighteen of the RIF(r), INH(r), and multidrug-resistant strains sequenced were tested by our real-time PCR assay; and full concordance of the results of the PCR with the sequencing data was obtained. In addition, a blind test was performed with a panel of 15 different susceptible and resistant strains from throughout Spain, and our results were also in 100% agreement with the sequencing data. Ours is the first assay based on rapid-cycle PCR able to simultaneously detect in a single reaction tube a large variety of mutations associated with RIF resistance (12 different mutations affecting 8 independent codons, including the most prevalent mutations at positions 526 and 531) and the most frequent INH resistance mutations. Our design could be a model for new, rapid genotypic methods able to simultaneously detect a wide variety of antibiotic resistance mutations.

Antitubercular Agents↗