Comparison of respiratory pathogen colonization and antimicrobial susceptibility in people with cystic fibrosis bronchiectasis versus non-cystic fibrosis bronchiectasis: a protocol for a systematic review.

BACKGROUND: Both cystic fibrosis (CF) and non-cystic fibrosis bronchiectasis are characterized by permanent bronchial dilation, impaired mucociliary clearance, and development of chronic colonization and infection. Although the major airway microbiota in both CF and non-CF bronchiectasis may be similar, there are some differences in clinical and microbiologic features. There may also be differences in antibiotic susceptibility patterns between the CF and non-CF populations. Therefore, analysis and comparison of the microbiota and antibiotic susceptibility pattern in CF bronchiectasis versus non-CF bronchiectasis would help to improve the management of both conditions. METHODS: Two authors will independently search the electronic databases PubMed, EMBASE, the Cochrane Library, and LIVIVO, for studies reporting bacterial colonization of the respiratory tract in adults and children diagnosed with bronchiectasis in either CF or non-CF. We will include studies examining any respiratory tract specimen, using conventional bacterial culture or other specialized techniques such as molecular methods. We will also examine the antimicrobial susceptibility patterns in people with CF bronchiectasis versus non-CF bronchiectasis. The authors will independently assess the risk of bias in each included study using the Newcastle Ottawa Scale (NOS). We will present the data with descriptive statistics and provide pooled estimates of outcomes, wherever it is feasible to perform meta-analysis. Heterogeneity in studies will be explored by visual inspection of forest plots as well as using the Higgins and Thompson I2 method. We will contact the corresponding authors of studies where data is/are missing and try to obtain the missing data. We will undertake sensitivity analysis to explore the impact of study quality and subgroup analysis based on pre-set criteria. We will prepare a summary of findings' table and assess the confidence in the evidence using the GRADE methodology. DISCUSSION: To date, there are no locally applicable evidence-based guidelines for antimicrobial treatment of non-CF bronchiectasis patients. In general, treatment is based on extrapolation of evidence in people with CF bronchiectasis. An insight into the microbiota and antimicrobial susceptibility patterns in the two conditions would facilitate appropriate rather than empiric antimicrobial therapy and hopefully reduce the burden of antimicrobial resistance created by rampant usage of antibiotics. SYSTEMATIC REVIEW REGISTRATION: The protocol has been registered in PROSPERO on July 26, 2020 (PROSPERO registration number: CRD42020193859 ).

Comparative Evaluation of Broth Microdilution with Polystyrene and Glass-Coated Plates, Agar Dilution, E-Test, Vitek, and Disk Diffusion for Susceptibility Testing of Colistin and Polymyxin B on Carbapenem-Resistant Clinical Isolates of Acinetobacter baumannii.

INTRODUCTION: With the increasing threat of multidrug-resistant organisms, such as Acinetobacter baumannii, the polymyxin class of drugs (colistin and polymyxin B) has become popular in clinical practice. A better understanding of antimicrobial susceptibility testing methods for colistin and polymyxin B is needed for optimal patient management. MATERIALS AND METHODS: Forty-two carbapenem-resistant A. baumannii isolates were subjected to susceptibility testing for colistin and polymyxin B using the following methods: broth microdilution (BMD) (glass-coated plates [BMD-Gs] and polystyrene plates [BMD-Ps]), agar dilution (AD), E-test®, Vitek®, and disk diffusion. Using BMD as the gold standard, comparative analysis between different methods was carried out. RESULTS: With BMD-Gs as reference, reliability was high for BMD-Ps and moderate for AD and Vitek for both the drugs. Similar results were obtained when the BMD-P was used as reference, but drug-polystyrene interaction was observed. CONCLUSION: Different susceptibility testing methods for polymyxins show great variation in their results and BMD using glass-coated plates can be considered the best candidate for gold standard.