RESUMO
Aim: Polymyxin B (PMB) is one of the few therapeutic options for treating infections caused by carbapenem-resistant Gram-negative bacteria (CR-GNB). However, the emergence of PMB-resistant CR-GNB strains has prompted the exploration of antibiotic adjuvants as potential therapeutic avenues. Thus, this study evaluates the potential of 3,5-dinitrobenzoic acid derivatives (DNH01, DNH11, DNH13 and DNH20) and isoniazid-N-acylhydrazones (INZ1-7, INZ9 and INZ11) as adjuvants to enhance PMB efficacy against CR-GNB.Materials & methods: MIC, MBC and drug combination assays were conducted using multidrug-resistant clinical isolates of Enterobacterales and Acinetobacter baumannii. In addition, the effects of PMB and PMB + DNH derivatives were assessed through flow cytometry and scanning electron microscopy (SEM).Results: DNH01, DNH11 and DNH20, unlike the INH-acylhydrazones, significantly restored PMB activity (MIC ≤ 2 µg/ml) in 80% of the tested isolates. Flow cytometry and SEM assays confirmed that DNH derivatives rescued the activity of PMB, yielding results comparable to those expected for PMB alone but at 256-fold lower concentrations.Conclusion: These findings suggest DNH derivatives hold substantial promise as PMB adjuvants to combat PMB-resistant CR-GNB infections.
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RESUMO
AIM: To investigate whether Brazilian green propolis improves the immune response against recurrent form isolate recurrent vulvovaginal candidiasis (RVVC) caused by Candida albicans by increasing neutrophil oxidative burst. MATERIALS & METHODS: We evaluated oxidant species production, oxygen consumption, microbicidal activity and myeloperoxidase activity in neutrophils previously treated with propolis and activated with different isolates of C. albicans (RVVC), vulvovaginal candidiasis, asymptomatic isolates and the reference strain. RESULTS: Propolis significantly increased oxidant species production, oxygen consumption, microbicidal activity and myeloperoxidase activity of neutrophils against different isolates of C. albicans including RVVC isolate that are considered resistant to the microbicidal activity of neutrophils. CONCLUSION: Brazilian green propolis may increase neutrophil burst oxidative response to RVVC leading to an efficient removal of C. albicans.