Santa Clara Valley Medical Center
Hospital / health systemSan Jose, California, United States
Research output, citation impact, and the most-cited recent papers from Santa Clara Valley Medical Center (United States). Aggregated across the NobleBlocks index of 300M+ scholarly works.
Top-cited papers from Santa Clara Valley Medical Center
Aspergillus species have emerged as an important cause of life-threatening infections in immunocompromised patients. This expanding population is composed of patients with prolonged neutropenia, advanced HIV infection, and inherited immunodeficiency and patients who have undergone allogeneic hematopoietic stem cell transplantation (HSCT) and/or lung transplantation. This document constitutes the guidelines of the Infectious Diseases Society of America for treatment of aspergillosis and replaces the practice guidelines for Aspergillus published in 2000 The objective of these
No controlled trials of therapy for invasive aspergillosis have been done. This review appraises 2,121 cases reported in 497 articles in the literature and analyzes 440 courses of treatment of infection at various body sites in 379 patients. The exclusion of early failures of therapy skews the results toward a favorable outcome. The rate of response to amphotericin B is 55%. Mortality from pulmonary aspergillosis in bone marrow transplant recipients exceeds 94% regardless of therapy, as does that from cerebral aspergillosis in all hosts. Amphotericin B (1 mg/[kg.d]) with flucytosine lowers mortality in neutropenic patients with pulmonary aspergillosis who did not receive a bone marrow transplant; relapse is common. Surgical debridement of aspergillus maxillary sinusitis is usually curative in nonimmunocompromised patients, whereas it increases mortality among neutropenic patients. Valve replacement is essential for aspergillus endocarditis. Both vitrectomy and intravitreal amphotericin B treatment are essential for aspergillus endophthalmitis. Flucytosine is somewhat useful clinically. Itraconazole shows efficacy in the treatment of pulmonary, skeletal, and pericardial aspergillosis. Although liposomal amphotericin B is less toxic than standard preparations of the drug, relevant data are limited. The proposed potentiation of amphotericin B by rifampin is unsupported by clinical data. Despite "conventional" therapy, mortality from invasive aspergillosis remains high; new approaches must be investigated.
BACKGROUND: Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age. OBJECTIVES: To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies. SEARCH STRATEGY: A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators. SELECTION CRITERIA: Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. DATA COLLECTION AND ANALYSIS: The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data. MAIN RESULTS: Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies. AUTHORS' CONCLUSIONS: There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.
Aspergillosis comprises a variety of manifestations of infection. These guidelines are directed to 3 principal entities: invasive aspergillosis, involving several organ systems (particularly pulmonary disease); pulmonary aspergilloma; and allergic bronchopulmonary aspergillosis. The recommendations are distilled in this summary, but the reader is encouraged to review the more extensive discussions in subsequent sections, which show the strength of the recommendations and the quality of the evidence, and the original publications cited in detail. Invasive aspergillosis. Because it is highly lethal in the immunocompromised host, even in the face of therapy, work-up must be prompt and aggressive, and therapy may need to be initiated upon suspicion of the diagnosis, without definitive proof (BIII). Intravenous therapy should be used initially in rapidly progressing disease (BIII). The largest therapeutic experience is with amphotericin B deoxycholate, which should be given at maximum tolerated doses (e.g., 1-1.5 mg/kg/d) and should be continued, despite modest increases in serum creatinine levels (BIII). Lipid formulations of amphotericin are indicated for the patient who has impaired renal function or who develops nephrotoxicity while receiving deoxycholate amphotericin (AII). Oral itraconazole is an alternative for patients who can take oral medication, are likely to be adherent, can be demonstrated (by serum level monitoring) to absorb the drug, and lack the potential for interaction with other drugs (BII). Oral itraconazole is attractive for continuing therapy in the patient who responds to initial iv therapy (CIII). Therapy should be prolonged beyond resolution of disease and reversible underlying predispositions (BIII). Adjunctive therapy (particularly surgery and combination chemotherapy, also immunotherapy), may be useful in certain situations (CIII). Aspergilloma. The optimal treatment strategy for aspergilloma is unknown. Therapy is predominantly directed at preventing life-threatening hemoptysis. Surgical removal of aspergilloma is definitive treatment, but because of significant morbidity and mortality it should be reserved for high-risk patients such as those with episodes of life-threatening hemoptysis, and considered for patients with underlying sarcoidosis, immunocompromised patients, and those with increasing Aspergillus-specific IgG titers (CIII). Surgical candidates would need to have adequate pulmonary function to undergo the operation. Bronchial artery embolization rarely produces a permanent success, but may be useful as a temporizing procedure in patients with life-threatening hemoptysis. Endobronchial and intracavitary instillation of antifungals or oral itraconazole may be useful for this condition. Since the majority of aspergillomas do not cause life-threatening hemoptysis, the morbidity and cost of treatment must be weighed against the clinical benefit. Allergic bronchopulmonary aspergillosis (APBA). Although no well-designed studies have been carried out, the available data support the use of corticosteroids for acute exacerbations of ABPA (AII). Neither the optimal corticosteroid dose nor the duration of therapy has been standardized, but limited data suggest the starting dose should be approximately 0.5 mg/kg/d of prednisone. The decision to taper corticosteroids should be made on an individual basis, depending on the clinical course (BIII). The available data suggest that clinical symptoms alone are inadequate to make such decisions, since significant lung damage may occur in asymptomatic patients. Increasing serum IgE levels, new or worsening infiltrate on chest radiograph, and worsening spirometry suggest that corticosteroids should be used (BII). Multiple asthmatic exacerbations in a patient with ABPA suggest that chronic corticosteroid therapy should be used (BIII). Itraconazole appears useful as a corticosteroid sparing agent (BII). (ABSTRACT TRUNCATED)
Because of the difficulties of recognizing allergic bronchopulmonary aspergillosis (ABPA) in the context of cystic fibrosis (because of overlapping clinical, radiographic, microbiologic, and immunologic features), advances in our understanding of the pathogenesis of allergic aspergillosis, new possibilities in therapy, and the need for agreed-upon definitions, an international consensus conference was convened. Areas addressed included fungal biology, immunopathogenesis, insights from animal models, diagnostic criteria, epidemiology, the use of new immunologic and genetic techniques in diagnosis, imaging modalities, pharmacology, and treatment approaches. Evidence from the existing literature was graded, and the consensus views were synthesized into this document and recirculated for affirmation. Virulence factors in Aspergillus that could aggravate these diseases, and particularly immunogenetic factors that could predispose persons to ABPA, were identified. New information has come from transgenic animals and recombinant fungal and host molecules. Diagnostic criteria that could provide a framework for monitoring were adopted, and helpful imaging features were identified. New possibilities in therapy produced plans for managing diverse clinical presentations.
Nonalcoholic fatty liver disease (NAFLD) is defined as the presence of hepatic fat accumulation after the exclusion of other causes of hepatic steatosis, including other causes of liver disease, excessive alcohol consumption, and other conditions that may lead to hepatic steatosis. NAFLD encompasses a broad clinical spectrum ranging from nonalcoholic fatty liver to nonalcoholic steatohepatitis (NASH), advanced fibrosis, cirrhosis, and finally hepatocellular carcinoma (HCC). NAFLD is the most common liver disease in the world and NASH may soon become the most common indication for liver transplantation. Ongoing persistence of obesity with increasing rate of diabetes will increase the prevalence of NAFLD, and as this population ages, many will develop cirrhosis and end-stage liver disease. There has been a general increase in the prevalence of NAFLD, with Asia leading the rise, yet the United States is following closely behind with a rising prevalence from 15% in 2005 to 25% within 5 years. NAFLD is commonly associated with metabolic comorbidities, including obesity, type II diabetes, dyslipidemia, and metabolic syndrome. Our understanding of the pathophysiology of NAFLD is constantly evolving. Based on NAFLD subtypes, it has the potential to progress into advanced fibrosis, end-stage liver disease and HCC. The increasing prevalence of NAFLD with advanced fibrosis, is concerning because patients appear to experience higher liver-related and non-liver-related mortality than the general population. The increased morbidity and mortality, healthcare costs and declining health related quality of life associated with NAFLD makes it a formidable disease, and one that requires more in-depth analysis.
BACKGROUND: Invasive aspergillosis is an important cause of morbidity and mortality in immunocompromised patients. Current treatments provide limited benefit. Posaconazole is an extended-spectrum triazole with in vitro and in vivo activity against Aspergillus species. METHODS: We investigated the efficacy and safety of posaconazole oral suspension (800 mg/day in divided doses) as monotherapy in an open-label, multicenter study in patients with invasive aspergillosis and other mycoses who were refractory to or intolerant of conventional antifungal therapy. Data from external control cases were collected retrospectively to provide a comparative reference group. RESULTS: Cases of aspergillosis deemed evaluable by a blinded data review committee included 107 posaconazole recipients and 86 control subjects (modified intent-to-treat population). The populations were similar and balanced with regard to prespecified demographic and disease variables. The overall success rate (i.e., the data review committee-assessed global response at the end of treatment) was 42% for posaconazole recipients and 26% for control subjects (odds ratio, 4.06; 95% confidence interval, 1.50-11.04; P=.006). The differences in response between the modified intent-to-treat treatment groups were preserved across additional, prespecified subsets, including infection site (pulmonary or disseminated), hematological malignancy, hematopoietic stem cell transplantation, baseline neutropenia, and reason for enrollment (patient was refractory to or intolerant of previous antifungal therapy). An exposure-response relationship was suggested by pharmacokinetic analyses. CONCLUSIONS: Although the study predates extensive use of echinocandins and voriconazole, these findings demonstrate that posaconazole is an alternative to salvage therapy for patients with invasive aspergillosis who are refractory to or intolerant of previous antifungal therapy.
This review summarizes knowledge on various aspects of paracoccidioidomycosis. Mycelial propagules, chlamydospores, and arthroconidia exhibit thermal dimorphism; arthroconidia are infectious in animals and, by electron microscopy, appear well provided for survival. The mycelial-to-yeast-phase transformation requires a strict control of glucan synthesis probably mediated by membrane enzymes. Hormonal influences on the transformation of the fungus (mycelium or conidium to yeast phase) have been demonstrated. Estrogen-binding proteins have been detected in the fungal cytosol, and during the transformation novel proteins are produced as a result of estradiol incorporation. Clinical forms have been better defined on the basis of better experimental models. Emphasis has been placed on the lungs as the portal of entry and on the existence of silent pulmonary infections. A specific Paracoccidioides brasiliensis antigen, the 43-kDa glycoprotein (Gp43), has been identified, characterized, and cloned. This has led to improved reproducibility and specificity of serologic tests. The depression of cell-mediated immune responses has been associated with severe disease in humans and in the experimental host. T-cell subsets in patients' tissues were characterized by means of monoclonal antibodies, and a reduced CD4/CD8 ratio was demonstrated. This has been related to alterations in lymphokine and tumor necrosis factor production, production of antigen-antibody complexes, etc. Amphotericin B has provided effective therapy. Azole derivatives have also improved prognosis and facilitated therapy. Itraconazole is presently the drug of choice, yet incapacitating sequelae (mainly pulmonary fibrosis) still constitute major problems.
AIM: To quantify the effects of hormone-replacement therapy (HRT) on components of the metabolic syndrome in postmenopausal women. METHODS: Comprehensive searches of electronic databases were performed from April 1966 to October 2004. We included randomized controlled trials that were of at least 8 weeks duration and evaluated the effect of HRT on metabolic, inflammatory or thrombotic components. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR). Subgroup analysis evaluated the effects for transdermal and oral treatment and for diabetic and non-diabetic women. RESULTS: Pooled results of 107 trials showed that HRT reduced abdominal fat [-6.8% (CI, -11.8 to -1.9%)], HOMA-IR [-12.9% (CI, -17.1 to -8.6%)] and new-onset diabetes [relative risk 0.7 (CI, 0.6-0.9)] in women without diabetes. In women with diabetes, HRT reduced fasting glucose [-11.5% (CI, -18.0 to -5.1%)] and HOMA-IR [-35.8% (CI, -51.7 to -19.8%)]. HRT also reduced low-density lipoprotein/high-density lipoprotein cholesterol ratio [-15.7% (CI, -18.0 to -13.5%)], lipoprotein(a) [Lp(a)] [-25.0% [CI, -32.9 to -17.1%)], mean blood pressure [-1.7% (CI, -2.9 to -0.5%)], E-selectin [-17.3% (CI, -22.4 to -12.1%)], fibrinogen [-5.5% (CI, -7.8 to -3.2%)] and plasminogen activator inhibitor-1 [-25.1% (CI, -33.6 to -15.5%)]. Oral agents produced larger beneficial effects than transdermal agents, but increased C-reactive protein (CRP) [37.6% (CI, 17.4-61.3%)] and decreased protein S [-8.6% CI, -13.1 to -4.1%)], while transdermal agents had no effect. CONCLUSIONS: HRT reduces abdominal obesity, insulin resistance, new-onset diabetes, lipids, blood pressure, adhesion molecules and procoagulant factors in women without diabetes and reduced insulin resistance and fasting glucose in women with diabetes. Oral agents adversely affected CRP and protein S, while transdermal agents had no effects.
Seven patients developed chronic and severe parkinsonism after repeatedly injecting 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intravenously. Levodopa and bromocriptine controlled the symptoms; however, within months, five of the seven patients experienced dyskinesias or on-off fluctuations. Therefore, neither prolonged levodopa treatment nor progressive disease was necessary for on-off phenomena. Because the neurotoxic effects of MPTP seem limited to the substantia nigra, damage to this system alone may produce all the motor features of Parkinson's disease. MPTP differs from other neurotoxins in that it consistently produces a pure parkinsonian state.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a neurotoxin which produces permanent parkinsonism in human and nonhuman primates. Treatment of squirrel monkeys with pargyline, a monoamine oxidase (MAO) inhibitor, prevents both clinical and neuropathological evidence of the neurotoxic effects of MPTP. Pargyline also inhibits conversion of MPTP to 1-methyl-4-phenylpyridinium ion (MPP+), a metabolic step that occurs rapidly after administration of MPTP in animals not treated with pargyline. It is proposed that the conversion of MPTP to MPP+, possibly involving MAO, may be important for the neurotoxic effects of MPTP to take place, and MPTP itself may not be the neurotoxic agent.
OBJECTIVE: To correlate self-reported antiretroviral adherence with virologic suppression. DESIGN: Prospective observational study of adherence to therapy nested in a randomized comparative trial of frequent versus infrequent monitoring of plasma HIV RNA. SETTING: Five university-affiliated HIV clinics. PATIENTS: A group of 173 HIV-infected patients with a mean baseline CD4 count of 142 x 10(6) cells/l (range 3-515) of whom 164 and 119 completed adherence questionnaires at 2 and 6 months, respectively. INTERVENTION: Individualized, unrestricted antiretroviral therapy. MEASUREMENTS: Patients were classified into four groups by adherence to therapy in the previous 4 weeks (< 80%, 80-95%, 95-99%, 100%). Plasma HIV RNA levels and CD4 lymphocyte counts were measured bimonthly. RESULTS: Recreational drug or alcohol use was associated with decreased adherence, whereas frequency of HIV RNA monitoring, demographic variables, (age, gender, education, and risk group) and stage of disease had no effect. Greater HIV suppression at 6 months was seen across four categories of increasing adherence (P = 0.009 for linear trend). Patients reporting < 80% adherence at 6 months had a 0.2 log10 copies/ml increase in HIV RNA and a loss of 19 x 10(6) CD4 cells/l compared with a 1.1 log10 copies/ml decrease in HIV RNA and an increase of 72 x 10(6) CD4 cells/l in those reporting 100% adherence (P = 0.02). CONCLUSION: Self-reported poor adherence (< 80%) and drug or alcohol use predicted non-response of HIV RNA at 6 months of antiretroviral therapy.
BACKGROUND: Allergic bronchopulmonary aspergillosis is a hypersensitivity disorder that can progress from an acute phase to chronic disease. The main treatment is systemic corticosteroids, but data from uncontrolled studies suggest that itraconazole, an orally administered antifungal agent, may be an effective adjunctive therapy. METHODS: We conducted a randomized, double-blind trial of treatment with either 200 mg of itraconazole twice daily or placebo for 16 weeks in patients who met immunologic and pulmonary-function criteria for corticosteroid-dependent allergic bronchopulmonary aspergillosis. A response was defined as a reduction of at least 50 percent in the corticosteroid dose, a decrease of at least 25 percent in the serum IgE concentration, and one of the following: an improvement of at least 25 percent in exercise tolerance or pulmonary-function tests or resolution or absence of pulmonary infiltrates. In a second, open-label part of the trial, all the patients received 200 mg of itraconazole per day for 16 weeks. RESULTS: There were responses in 13 of 28 patients in the itraconazole group (46 percent), as compared with 5 of 27 patients in the placebo group (19 percent, P=0.04). The rate of adverse events was similar in the two groups. In the subsequent open-label phase, 12 of the 33 patients who had not had a response during the double-blind phase (36 percent) had responses, and none of the patients who had a response in the double-blind phase of the trial had a relapse. CONCLUSIONS: For patients with corticosteroid-dependent allergic bronchopulmonary aspergillosis, the addition of itraconazole can lead to improvement in the condition without added toxicity.
At one time, the diagnosis of a deficiency of vitamin B12 or folate was considered to be relatively straightforward. As knowledge has accumulated, the limitations of such tests as serum vitamin level measurements and the Schilling test have become apparent. With the development of newer tests, atypical and subclinical deficiency states have been recognized. In this review, available tests used in the diagnosis of vitamin B12 and folate deficiency are discussed, and a rational approach to the diagnosis of these deficiency states is presented.
BACKGROUND: Incomplete adherence to tuberculosis (TB) treatment increases the risk of delayed culture conversion with continued transmission in the community, as well as treatment failure, relapse, and development or amplification of drug resistance. We conducted a systematic review and meta-analysis of adherence interventions, including directly observed therapy (DOT), to determine which approaches lead to improved TB treatment outcomes. METHODS AND FINDINGS: We systematically reviewed Medline as well as the references of published review articles for relevant studies of adherence to multidrug treatment of both drug-susceptible and drug-resistant TB through February 3, 2018. We included randomized controlled trials (RCTs) as well as prospective and retrospective cohort studies (CSs) with an internal or external control group that evaluated any adherence intervention and conducted a meta-analysis of their impact on TB treatment outcomes. Our search identified 7,729 articles, of which 129 met the inclusion criteria for quantitative analysis. Seven adherence categories were identified, including DOT offered by different providers and at various locations, reminders and tracers, incentives and enablers, patient education, digital technologies (short message services [SMSs] via mobile phones and video-observed therapy [VOT]), staff education, and combinations of these interventions. When compared with DOT alone, self-administered therapy (SAT) was associated with lower rates of treatment success (CS: risk ratio [RR] 0.81, 95% CI 0.73-0.89; RCT: RR 0.94, 95% CI 0.89-0.98), adherence (CS: RR 0.83, 95% CI 0.75-0.93), and sputum smear conversion (RCT: RR 0.92, 95% CI 0.87-0.98) as well as higher rates of development of drug resistance (CS: RR 4.19, 95% CI 2.34-7.49). When compared to DOT provided by healthcare providers, DOT provided by family members was associated with a lower rate of adherence (CS: RR 0.86, 95% CI 0.79-0.94). DOT delivery in the community versus at the clinic was associated with a higher rate of treatment success (CS: RR 1.08, 95% CI 1.01-1.15) and sputum conversion at the end of two months (CS: RR 1.05, 95% CI 1.02-1.08) as well as lower rates of treatment failure (CS: RR 0.56, 95% CI 0.33-0.95) and loss to follow-up (CS: RR 0.63, 95% CI 0.40-0.98). Medication monitors improved adherence and treatment success and VOT was comparable with DOT. SMS reminders led to a higher treatment completion rate in one RCT and were associated with higher rates of cure and sputum conversion when used in combination with medication monitors. TB treatment outcomes improved when patient education, healthcare provider education, incentives and enablers, psychological interventions, reminders and tracers, or mobile digital technologies were employed. Our findings are limited by the heterogeneity of the included studies and lack of standardized research methodology on adherence interventions. CONCLUSION: TB treatment outcomes are improved with the use of adherence interventions, such as patient education and counseling, incentives and enablers, psychological interventions, reminders and tracers, and digital health technologies. Trained healthcare providers as well as community delivery provides patient-centered DOT options that both enhance adherence and improve treatment outcomes as compared to unsupervised, SAT alone.
BACKGROUND AND METHODS: Symptomatic pulmonary aspergillosis has rarely been reported in patients with the acquired immunodeficiency syndrome (AIDS). We describe the predisposing factors, the clinical and radiologic features, and the therapeutic outcomes in 13 patients with pulmonary aspergillosis, all of whom had human immunodeficiency virus (HIV) infection and 12 of whom had AIDS. RESULTS: Pulmonary aspergillosis was detected a median of 25 months after the diagnosis of AIDS, usually following corticosteroid use, neutropenia, pneumonia due to other pathogens, marijuana smoking, or the use of broad-spectrum antibiotics. Two major patterns of disease were observed: invasive aspergillosis (in 10 patients) and obstructing bronchial aspergillosis (in 3). Cough and fever, the most common symptoms, tended to be insidious in onset in patients with invasive disease (median duration, 1.3 months before diagnosis). Breathlessness, cough, and chest pain predominated in the three patients with obstructing bronchial aspergillosis, who coughed up fungal casts. Radiologic patterns included upper-lobe cavitary disease (sometimes mistaken for tuberculosis), nodules, pleural-based lesions, and diffuse infiltrates, usually of the lower lobe. Transbronchial biopsies were usually negative, but positive cultures were obtained from bronchoalveolar-lavage fluid or percutaneous aspirates. Dissemination to other organs occurred in at least two patients, and direct invasion of extrapulmonary sites was seen in two others. The results of treatment with amphotericin B, itraconazole, or both were variable. Ten of the patients died a median of 3 months after the diagnosis (range, 0 to 12 months). CONCLUSIONS: Pulmonary aspergillosis is a possible late complication of AIDS; if diagnosed early, it may be treated successfully.
his document presents consensus panel recommendations for the medical care of pregnant women with preexisting diabetes, including type 1 and type 2 diabetes. The intent is to help clinicians deal with the broad spectrum of problems that arise in management of diabetes before and during pregnancy, and to prepare diabetic women for treatment that may reduce complications in the years after pregnancy. A thorough discussion of the evidence supporting the recommendations is presented in the book,
Methicillin-resistant Staphylococcus aureus, first identified just over 4 decades ago, has undergone rapid evolutionary changes and epidemiologic expansion. It has spread beyond the confines of health care facilities, emerging anew in the community, where it is rapidly becoming a dominant pathogen. This has led to an important change in the choice of antibiotics in the management of community-acquired infections and has also led to the development of novel antimicrobials.
Resistance to azole antifungals continues to be a significant problem in the common fungal pathogen Candida albicans. Many of the molecular mechanisms of resistance have been defined with matched sets of susceptible and resistant clinical isolates from the same strain. Mechanisms that have been identified include alterations in the gene encoding the target enzyme ERG11 or overexpression of efflux pump genes including CDR1, CDR2, and MDR1. In the present study, a collection of unmatched clinical isolates of C. albicans was analyzed for the known molecular mechanisms of resistance by standard methods. The collection was assembled so that approximately half of the isolates were resistant to azole drugs. Extensive cross-resistance was observed for fluconazole, clotrimazole, itraconazole, and ketoconazole. Northern blotting analyses indicated that overexpression of CDR1 and CDR2 correlates with resistance, suggesting that the two genes may be coregulated. MDR1 overexpression was observed infrequently in some resistant isolates. Overexpression of FLU1, an efflux pump gene related to MDR1, did not correlate with resistance, nor did overexpression of ERG11. Limited analysis of the ERG11 gene sequence identified several point mutations in resistant isolates; these mutations have been described previously. Two of the most common point mutations in ERG11 associated with resistance, D116E and E266D, were tested by restriction fragment length polymorphism analysis of the isolates from this collection. The results indicated that the two mutations occur frequently in different isolates of C. albicans and are not reliably associated with resistance. These analyses emphasize the diversity of mechanisms that result in a phenotype of azole resistance. They suggest that the resistance mechanisms identified in matched sets of susceptible and resistant isolates are not sufficient to explain resistance in a collection of unmatched clinical isolates and that additional mechanisms have yet to be discovered.
BACKGROUND: Long-acting beta-agonists may increase the risk for fatal and nonfatal asthma exacerbations. PURPOSE: To assess the risk for severe, life-threatening, or fatal asthma exacerbations associated with long-acting beta-agonists. DATA SOURCES: English- and non-English-language searches of MEDLINE, EMBASE, and Cochrane databases; the U.S. Food and Drug Administration Web site; and references of selected reviews through December 2005. STUDY SELECTION: Randomized, placebo-controlled trials that lasted at least 3 months and evaluated long-acting beta-agonist use in patients with asthma. All trials allowed the use of as-needed short-acting beta-agonists. DATA EXTRACTION: Outcomes measured were Peto odds ratio (OR) and risk difference of severe exacerbations requiring hospitalization, life-threatening exacerbations requiring intubation and ventilation, and asthma-related deaths. The OR for asthma-related deaths was obtained from the Salmeterol Multi-center Asthma Research Trial (SMART). DATA SYNTHESIS: Pooled results from 19 trials with 33 826 participants found that long-acting beta-agonists increased exacerbations requiring hospitalization (OR, 2.6 [95% CI, 1.6 to 4.3]) and life-threatening exacerbations (OR, 1.8 [CI, 1.1 to 2.9]) compared with placebo. Hospitalizations were statistically significantly increased with salmeterol (OR, 1.7 [CI, 1.1 to 2.7]) and formoterol (OR, 3.2 [CI, 1.7 to 6.0]) and in children (OR, 3.9 [CI, 1.7 to 8.8]) and adults (OR, 2.0 [CI, 1.1 to 3.9]). The absolute increase in hospitalization was 0.7% (CI, 0.1% to 1.3%) over 6 months. The risk for asthma-related deaths was increased (OR, 3.5 [CI, 1.3 to 9.3]), with a pooled risk difference of 0.07% (CI, 0.01% to 0.1%). LIMITATIONS: The small number of deaths limited the reliability in assessing this risk, and 28 studies did not report information on the outcomes of interest. CONCLUSIONS: Long-acting beta-agonists have been shown to increase severe and life-threatening asthma exacerbations, as well as asthma-related deaths.