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

RETRATO DE NIÑOS [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

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

Functional universality and evolutionary diversity: insights from the structure of the ribosome

AbstractThe structure of the mammalian ribosome, reconstructed at 25 å resolution, has added a new dimension to our current knowledge, as it manifests the conservation and universality of the ribosome in respect to its primary tasks in protein biosynthesis. A combined approach to study of the ribosome, using X-ray crystallography and electron microscopy, may further improve our understanding of ribosome function in the future

In Vitro Activities of the Rx-01 Oxazolidinones against Hospital and Community Pathogens▿

Rx-01_423 and Rx-01_667 are two members of the family of oxazolidinones that were designed using a combination of computational and medicinal chemistry and conventional biological techniques. The compounds have a two- to eightfold-improved potency over linezolid against serious gram-positive pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant streptococci, and vancomycin-resistant enterococci. This enhanced potency extends to the coverage of linezolid-resistant gram-positive microbes, especially multidrug-resistant enterococci and pneumococci. Compounds from this series expand the spectrum compared with linezolid to include fastidious gram-negative organisms like Haemophilus influenzae and Moraxella catarrhalis. Like linezolid, the Rx-01 compounds are bacteriostatic against MRSA and enterococci but are generally bactericidal against S. pneumoniae and H. influenzae