Alireza Kalbasi

Bio: Alireza Kalbasi is an academic researcher from Harvard University. The author has contributed to research in topics: Medicine & Cytokine. The author has an hindex of 8, co-authored 16 publications receiving 568 citations. Previous affiliations of Alireza Kalbasi include Pfizer & Brigham and Women's Hospital.

Systematic Review and Meta-analysis of Clinical and Economic Outcomes from the Implementation of Hospital-Based Antimicrobial Stewardship Programs

Abstract: The implementation of antimicrobial stewardship programs (ASPs) is a promising strategy to help address the problem of antimicrobial resistance. We sought to determine the efficacy of ASPs and their effect on clinical and economic parameters. We searched PubMed, EMBASE, and Google Scholar looking for studies on the efficacy of ASPs in hospitals. Based on 26 studies (extracted from 24,917 citations) with pre- and postimplementation periods from 6 months to 3 years, the pooled percentage change of total antimicrobial consumption after the implementation of ASPs was -19.1% (95% confidence interval [CI] = -30.1 to -7.5), and the use of restricted antimicrobial agents decreased by -26.6% (95% CI = -52.3 to -0.8). Interestingly, in intensive care units, the decrease in antimicrobial consumption was -39.5% (95% CI = -72.5 to -6.4). The use of broad-spectrum antibiotics (-18.5% [95% CI = -32 to -5.0] for carbapenems and -14.7% [95% CI = -27.7 to -1.7] for glycopeptides), the overall antimicrobial cost (-33.9% [95% CI = -42.0 to -25.9]), and the hospital length of stay (-8.9% [95% CI = -12.8 to -5]) decreased. Among hospital pathogens, the implementation of ASPs was associated with a decrease in infections due to methicillin-resistant Staphylococcus aureus (risk difference [RD] = -0.017 [95% CI = -0.029 to -0.005]), imipenem-resistant Pseudomonas aeruginosa (RD = -0.079 [95% CI = -0.114 to -0.040]), and extended-spectrum beta-lactamase Klebsiella spp. (RD = -0.104 [95% CI = -0.153 to -0.055]). Notably, these improvements were not associated with adverse outcomes, since the all-cause, infection-related 30-day mortality and infection rates were not significantly different after implementation of an ASP (RD = -0.001 [95% CI = -0.009 to 0.006], RD = -0.005 [95% CI = -0.016 to 0.007], and RD = -0.045% [95% CI = -0.241 to 0.150], respectively). Hospital ASPs result in significant decreases in antimicrobial consumption and cost, and the benefit is higher in the critical care setting. Infections due to specific antimicrobial-resistant pathogens and the overall hospital length of stay are improved as well. Future studies should focus on the sustainability of these outcomes and evaluate potential beneficial long-term effects of ASPs in mortality and infection rates.

Microfluidic Brain-on-a-Chip: Perspectives for Mimicking Neural System Disorders

Abstract: Neurodegenerative diseases (NDDs) include more than 600 types of nervous system disorders in humans that impact tens of millions of people worldwide. Estimates by the World Health Organization (WHO) suggest NDDs will increase by nearly 50% by 2030. Hence, development of advanced models for research on NDDs is needed to explore new therapeutic strategies and explore the pathogenesis of these disorders. Different approaches have been deployed in order to investigate nervous system disorders, including two-and three-dimensional (2D and 3D) cell cultures and animal models. However, these models have limitations, such as lacking cellular tension, fluid shear stress, and compression analysis; thus, studying the biochemical effects of therapeutic molecules on the biophysiological interactions of cells, tissues, and organs is problematic. The microfluidic “organ-on-a-chip” is an inexpensive and rapid analytical technology to create an effective tool for manipulation, monitoring, and assessment of cells, and investigating drug discovery, which enables the culture of various cells in a small amount of fluid (10−9 to 10−18 L). Thus, these chips have the ability to overcome the mentioned restrictions of 2D and 3D cell cultures, as well as animal models. Stem cells (SCs), particularly neural stem cells (NSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs) have the capability to give rise to various neural system cells. Hence, microfluidic organ-on-a-chip and SCs can be used as potential research tools to study the treatment of central nervous system (CNS) and peripheral nervous system (PNS) disorders. Accordingly, in the present review, we discuss the latest progress in microfluidic brain-on-a-chip as a powerful and advanced technology that can be used in basic studies to investigate normal and abnormal functions of the nervous system.

Bilirubin suppresses Th17 immunity in colitis by upregulating CD39

Abstract: Unconjugated bilirubin (UCB), a product of heme oxidation, has known immunosuppressant properties but the molecular mechanisms, other than antioxidant effects, remain largely unexplored. We note that UCB modulates T helper type 17 (Th17) immune responses, in a manner dependent upon heightened expression of CD39 ectonucleotidase. UCB has protective effects in experimental colitis, where it enhances recovery after injury and preferentially boosts IL-10 production by colonic intraepithelial CD4+ cells. In vitro, UCB confers immunoregulatory properties on human control Th17 cells, as reflected by increased levels of FOXP3 and CD39 with heightened cellular suppressor ability. Upregulation of CD39 by Th17 cells is dependent upon ligation of the aryl hydrocarbon receptor (AHR) by UCB. Genetic deletion of CD39, as in Entpd1-/- mice, or dysfunction of AHR, as in Ahrd mice, abrogates these UCB salutary effects in experimental colitis. However, in inflammatory bowel disease (IBD) samples, UCB fails to confer substantive immunosuppressive properties upon Th17 cells, because of decreased AHR levels under the conditions tested in vitro. Immunosuppressive effects of UCB are mediated by AHR resulting in CD39 upregulation by Th17. Boosting downstream effects of AHR via UCB or enhancing CD39-mediated ectoenzymatic activity might provide therapeutic options to address development of Th17 dysfunction in IBD.

Inappropriate Management of Asymptomatic Patients With Positive Urine Cultures: A Systematic Review and Meta-analysis.

Abstract: Background Mismanagement of asymptomatic patients with positive urine cultures (referred to as asymptomatic bacteriuria [ASB] in the literature) promotes antimicrobial resistance and results in unnecessary antimicrobial-related adverse events and increased health care costs. Methods We conducted a systematic review and meta-analysis of studies that reported on the rate of inappropriate ASB treatment published from 2004 to August 2016. The appropriateness of antimicrobial administration was based on guidelines published by the Infectious Diseases Society of America. Results A total of 2142 nonduplicate articles were identified, and among them 30 fulfilled our inclusion criteria. The pooled prevalence of antimicrobial treatment among 4129 cases who did not require treatment was 45% (95% CI, 39-50). Isolation of gram-negative pathogens (odds ratio [OR], 3.58; 95% CI, 2.12-6.06), pyuria (OR, 2.83; 95% CI, 1.9-4.22), nitrite positivity (OR, 3.83; 95% CI, 2.24-6.54), and female sex (OR, 2.11; 95% CI, 1.46-3.06) increased the odds of receiving treatment. The rates of treatment were higher in studies with ≥100 000 cfu/mL cutoff values compared with <10 000 cfu/mL for bacterial growth (P, .011). The implementation of educational and organizational interventions designed to eliminate the overtreatment of ASB resulted in a median absolute risk reduction of 33% (rangeARR, 16-36%, medianRRR, 53%; rangeRRR, 25-80%). Conclusion The mismanagement of ASB remains extremely frequent. Female sex and the overinterpretation of certain laboratory data (positive nitrites, pyuria, isolation of gram-negative bacteria and cultures with higher microbial count) are associated with overtreatment. Even simple stewardship interventions can be particularly effective, and antimicrobial stewardship programs should focus on the challenge of differentiating true urinary tract infection from ASB.

The aryl hydrocarbon receptor: an environmental sensor integrating immune responses in health and disease.

Abstract: The environment, diet, microbiota and body’s metabolism shape complex biological processes in health and disease. However, our understanding of the molecular pathways involved in these processes is still limited. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that integrates environmental, dietary, microbial and metabolic cues to control complex transcriptional programmes in a ligand-specific, cell-type-specific and context-specific manner. In this Review, we summarize our current knowledge of AHR and the transcriptional programmes it controls in the immune system. Finally, we discuss the role of AHR in autoimmune and neoplastic diseases of the central nervous system, with a special focus on the gut immune system, the gut–brain axis and the therapeutic potential of targeting AHR in neurological disorders. By sensing environmental, dietary, microbial and metabolic cues, the ligand-activated transcription factor aryl hydrocarbon receptor controls complex transcriptional programmes that are relevant to autoimmune, neoplastic, metabolic and degenerative diseases.

Effect of antibiotic stewardship on the incidence of infection and colonisation with antibiotic-resistant bacteria and Clostridium difficile infection: a systematic review and meta-analysis

Abstract: Summary Background Antibiotic stewardship programmes have been shown to reduce antibiotic use and hospital costs. We aimed to evaluate evidence of the effect of antibiotic stewardship on the incidence of infections and colonisation with antibiotic-resistant bacteria. Methods For this systematic review and meta-analysis, we searched PubMed, the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, and Web of Science for studies published from Jan 1, 1960, to May 31, 2016, that analysed the effect of antibiotic stewardship programmes on the incidence of infection and colonisation with antibiotic-resistant bacteria and Clostridium difficile infections in hospital inpatients. Two authors independently assessed the eligibility of trials and extracted data. Studies involving long-term care facilities were excluded. The main outcomes were incidence ratios (IRs) of target infections and colonisation per 1000 patient-days before and after implementation of antibiotic stewardship. Meta-analyses were done with random-effect models and heterogeneity was calculated with the I 2 method. Findings We included 32 studies in the meta-analysis, comprising 9 056 241 patient-days and 159 estimates of IRs. Antibiotic stewardship programmes reduced the incidence of infections and colonisation with multidrug-resistant Gram-negative bacteria (51% reduction; IR 0·49, 95% CI 0·35–0·68; p Staphylococcus aureus (37%; 0·63, 0·45–0·88; p=0·0065), as well as the incidence of C difficile infections (32%; 0·68, 0·53–0·88; p=0·0029). Antibiotic stewardship programmes were more effective when implemented with infection control measures (IR 0·69, 0·54–0·88; p=0·0030), especially hand-hygiene interventions (0·34, 0·21–0·54; p Interpretation Antibiotic stewardship programmes significantly reduce the incidence of infections and colonisation with antibiotic-resistant bacteria and C difficile infections in hospital inpatients. These results provide stakeholders and policy makers with evidence for implementation of antibiotic stewardship interventions to reduce the burden of infections from antibiotic-resistant bacteria. Funding German Center for Infection Research.

Opportunities and Challenges for Biosensors and Nanoscale Analytical Tools for Pandemics: COVID-19.

Abstract: Biosensors and nanoscale analytical tools have shown huge growth in literature in the past 20 years, with a large number of reports on the topic of 'ultrasensitive', 'cost-effective', and 'early detection' tools with a potential of 'mass-production' cited on the web of science Yet none of these tools are commercially available in the market or practically viable for mass production and use in pandemic diseases such as coronavirus disease 2019 (COVID-19) In this context, we review the technological challenges and opportunities of current bio/chemical sensors and analytical tools by critically analyzing the bottlenecks which have hindered the implementation of advanced sensing technologies in pandemic diseases We also describe in brief COVID-19 by comparing it with other pandemic strains such as that of severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) for the identification of features that enable biosensing Moreover, we discuss visualization and characterization tools that can potentially be used not only for sensing applications but also to assist in speeding up the drug discovery and vaccine development process Furthermore, we discuss the emerging monitoring mechanism, namely wastewater-based epidemiology, for early warning of the outbreak, focusing on sensors for rapid and on-site analysis of SARS-CoV2 in sewage To conclude, we provide holistic insights into challenges associated with the quick translation of sensing technologies, policies, ethical issues, technology adoption, and an overall outlook of the role of the sensing technologies in pandemics