In vivo studies on antibiotic combination for the treatment of carbapenem-resistant Gram-negative bacteria: a systematic review and meta-analysis protocol

ObjectiveThere is poor evidence to determine the superiority of combination regimens versus monotherapy against infections due to carbapenem-resistant (CR) Gram-negative bacteria. In vivo models can simulate the pathophysiology of infections in humans and assess antibiotic efficacy. We aim to investigate in vivo effects of antibiotic combination on mortality and disease burden for infections due to CR Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacteriaceae and provide an unbiased overview of existing knowledge. The results of the study can help prioritising future research on the most promising therapies against CR bacteria.Methods and analysisThis protocol was formulated using the Systematic Review Protocol for Animal Intervention Studies (SYRCLE) Checklist. Publications will be collected from PubMed, Scopus, Embase and Web of Science. Quality checklists adapted by Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies and SYRCLE's risk of bias tool will be used. If the meta-analysis seems feasible, the ES and the 95% CI will be analysed. The heterogeneity between studies will be assessed by I2 test. Subgroup meta-analysis will be performed when possible to assess the impact of the studies on efficacy of the treatments. Funnel plotting will be used to evaluate the risk of publication bias.DisseminationThis systematic review and meta-analysis is part of a wider research collaboration project, the COmbination tHErapy to treat sepsis due to carbapenem-Resistant bacteria in adult and paediatric population: EvideNCE and common practice (COHERENCE) study that includes also the analyses of in vitro and human studies. Data will be presented at international conferences and the results will be published in peer-reviewed journals.PROSPERO registration numberCRD42019128104(available at: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42019128104)

Systematic review and meta-analysis of in vitro efficacy of antibiotic combination therapy against carbapenem-resistant Gram-negative bacilli.

The superiority of combination therapy for carbapenem-resistant Gram-negative bacilli (CR-GNB) infections remains controversial. In vitro models may predict the efficacy of antibiotic regimens against CR-GNB. A systematic review and meta-analysis was performed including pharmacokinetic/pharmacodynamic (PK/PD) and time-kill (TK) studies examining the in vitro efficacy of antibiotic combinations against CR-GNB [PROSPERO registration no. CRD42019128104]. The primary outcome was in vitro synergy based on the effect size (ES): high, ES ≥ 0.75, moderate, 0.35ES0.75; low, ES ≤ 0.35; and absent, ES = 0). A network meta-analysis assessed the bactericidal effect and re-growth rate (secondary outcomes). An adapted version of the ToxRTool was used for risk-of-bias assessment. Over 180 combination regimens from 136 studies were included. The most frequently analysed classes were polymyxins and carbapenems. Limited data were available for ceftazidime/avibactam, ceftolozane/tazobactam and imipenem/relebactam. High or moderate synergism was shown for polymyxin/rifampicin against Acinetobacter baumannii [ES = 0.91, 95% confidence interval (CI) 0.44-1.00], polymyxin/fosfomycin against Klebsiella pneumoniae (ES = 1.00, 95% CI 0.66-1.00) and imipenem/amikacin against Pseudomonas aeruginosa (ES = 1.00, 95% CI 0.21-1.00). Compared with monotherapy, increased bactericidal activity and lower re-growth rates were reported for colistin/fosfomycin and polymyxin/rifampicin in K. pneumoniae and for imipenem/amikacin or imipenem/tobramycin against P. aeruginosa. High quality was documented for 65% and 53% of PK/PD and TK studies, respectively. Well-designed in vitro studies should be encouraged to guide the selection of combination therapies in clinical trials and to improve the armamentarium against carbapenem-resistant bacteria

Clinical management of severe infections caused by carbapenem-resistant Gram-negative bacteria: a worldwide cross-sectional survey addressing the use of antibiotic combinations.

OBJECTIVES: Optimal treatment of carbapenem-resistant Gram-negative (CR-GNB) infections is uncertain due to the lack of good-quality evidence and the limited effectiveness of available antibiotics. The aim of this survey was to investigate clinicians' prescribing strategies for treating CR-GNB infections worldwide. METHODS: A 36-items-questionnaire was developed addressing the following aspects of antibiotic prescribing: respondent's background, diagnostic and therapeutic availability, preferred antibiotic strategies and rationale for selecting combination therapy. Prescribers were recruited following the snowball-sampling approach, and a post-stratification correction with inverse proportional weights was used to adjust the sample's representativeness. RESULTS: 1012 respondents from 95 countries participated in the survey. Overall, 298 (30%) of respondents had local guidelines for treating CR-GNB at their facility and 702 (71%) had access to Infectious Diseases consultation, with significant discrepancies according to country economic status: 85% (390/502) in High-Income-Countries vs 59% (194/283) in Upper-Medium-Income-Countries and 30% (118/196) in Lower-Middle-Income-Countries/Lower-Income-Countries). Targeted regimens varied widely, ranging from 40 regimens for CR-Acinetobacter spp. to more than 100 regimens for CR-Enterobacteriaceae. Although the majority of respondents acknowledged the lack of evidence behind this choice, dual combination was the preferred treatment scheme and carbapenem-polymyxin was the most prescribed regimen, irrespective of pathogen and infection source. Respondents noticeably disagreed around the meaning of 'combination therapy' with 20% (150/783) indicating the simple addition of multiple compounds, 42% (321/783) requiring the presence of in vitro activity and 38% (290/783) of in vitro-synergism. CONCLUSIONS: Management of CR-GNB infections is far from being standardized. Strategic public health focussed randomised controlled trials are urgently required to inform evidence-based treatment guidelines

The role of combination therapy in the treatment of severe infections caused by carbapenem resistant gram-negatives: a systematic review of clinical studies

Abstract Background Effective treatment of sepsis due to carbapenem-resistant Gram-negative bacteria (CR-GNB) remains a challenge for clinicians worldwide. In recent years, the combination of antibiotics has become the preferred treatment strategy for CR-GNB infection. However, robust evidence to support this approach is lacking. This systematic review aimed at critically evaluating all available antibiotic options for CR-GNB sepsis with particular focus on combination. Methods We systematically searched published literature from January 1945 until December 2018 for observational comparative and non-comparative studies and randomized trials examining any antibiotic option for CR-GNB. Studies were included if reporting microbiologically-confirmed infection caused by Acinetobacter baumannii, Enterobacteriaceae/Klebsiella spp., or Pseudomonas aeruginosa, reporting at least one of the study outcomes, and definitive antibiotic treatment. Carbapenem-resistance was defined as phenotypically-detected in vitro resistance to at least one of the following carbapenems: doripenem, ertapenem, imipenem, meropenem. Each antibiotic regimen was classified as “defined” when at least the molecular class(es) composing the regimen was detailed. Primary outcomes were 30-day and attributable mortality. Bayesian network meta-analysis (NMA) approach was selected for quantitative synthesis to explore feasibility of pooling data on antibiotic regimens. Results A total of 6306 records were retrieved and 134 studies including 11,546 patients were included: 54 studies were on Acinetobacter, 52 on Enterobacteriaceae/Klebsiella, 21 on mixed Gram-negative, and 7 on Pseudomonas. Nine (7%) were RCTs; 19 prospective cohorts (14%), 89 (66%) retrospective, and 17 (13%) case series. Forty-one studies (31%) were multicentric. Qualitative synthesis showed an heterogeneous and scattered reporting of key-clinical and microbiological variables across studies. Ninety-two distinct antibiotic regimens were identified with 47 of them (51%, 5863 patients) not reporting any details on numbers, type, dosage and in vitro activity of the included antibiotic molecules. The NMAs could not be performed for any of the selected outcome given the presence of too many disconnected components. Conclusion The existing evidence is insufficient to allowing for the formulation of any evidence-based therapeutic recommendation for CR-GNB sepsis. Future studies must provide a standardized definition of antibiotic regimen to drive recommendations for using combination of antibiotics that can be reliably applied to clinical practice

In vivo studies on antibiotic combination for the treatment of carbapenem-resistant Gram-negative bacteria: a systematic review and meta-analysis protocol

Systematic review and meta-analysis protocol for in vivo studies describing combination treatments for Gram-negative MDR bacteri

Systematic review and meta-analysis of in vitro efficacy of antibiotic combination therapy against carbapenem-resistant Gram-negative bacilli

BACKGROUND: The superiority of combination therapy for carbapenem-resistant Gram-negative bacilli (CR-GNB) remains controversial. In vitro models may predict the efficacy of antibiotic regimens against CR-GNB.METHODS: A systematic review and meta-analysis were performed including pharmacokinetic/pharmacodynamic (PK/PD) and time-kill (TK) studies examining in vitro efficacy of antibiotic combinations against CR-GNB. Prospero registration number is CRD42019128104. Primary outcome was in vitro synergy (effect size, ES: high 65 075, moderate 035 < ES < 075, low 64 035, absent\u202f=\u202f0). A network meta-analysis assessed bactericidal effect and regrowth rate (secondary outcomes). An adapted version of the ToxRTool was used for risk of bias assessment.FINDINGS: Over 180 combination regimens from 136 studies were included. The most frequently analysed classes were polymyxins and carbapenems. Limited data were available for ceftazidime/avibactam, ceftolozane/tazobactam and imipenem/relebactam. High or moderate synergism was shown for polymyxin-rifampicin combination against Acinetobacter baumannii (ES 091, 95% CI 044 - 100), polymyxin-fosfomycin against Klebsiella pneumoniae (ES 100, 95% CI 066 - 100) and for imipenem and amikacin against Pseudomonas aeruginosa (ES 100, 95% CI 021 - 100). Compared to monotherapy, increased bactericidal activity and lower regrowth rates were reported for colistin-fosfomycin and polymyxin-rifampicin in K. pneumoniae and for imipenem-amikacin or tobramycin against P. aeruginosa. High quality was documented for 65% and 53% of PK/PD and TK studies, respectively.INTERPRETATION: Well-designed in vitro studies should be encouraged to guide the selection of combination therapies in clinical trials and improve the armamentarium against CR bacteria

Per Domenico De Robertis. Studi offerti dagli allievi fiorentini

Dalla letteratura delle origini alla contemporaneità, i diciassette saggi raccolti nel volume rispecchiano la vastità di interessi e di competenze del destinatario impegnando varie metodologie linguistico-filologiche, dalla metricologia (applicata al testo duecentesco anonimo dell'Intelligenza), alla lessicologia (su Manzoni e Leopardi), lo studio delle fonti e l'intertestualità (su Cavalcanti, Petrarca, Boccaccio, Pascoli, Montale e Ferlinghetti), l'edizione dei testi (è il caso del ritrovamento di un volume inedito di Margherita Guidacci, ma anche di una proposta ecdotica per Nicolò De Rossi), la codicologia e la storia della lingua (i codici Benci e un nuovo monumento dell'antico aretino), la ricerca storica (sugli anni svizzeri di Silone), fino all'impegnativa prova di traduzione e commento dei Carmina di Baldassarre Castiglione. Ne risulta un quadro mobile e vivace di una scuola critica che si propone per la sua fedeltà al testo letterario, per la coerenza metodologica e per un'assidua attività di ricerca archivistica ed esplorazione della tradizione