In vitro interactions of ambroxol hydrochloride or amlodipine in combination with antibacterial agents against carbapenem-resistant Acinetobacter baumannii

Synergistic combination of carvedilol, amlodipine, amitriptyline, and antibiotics as an alternative treatment approach for the susceptible and multidrug-resistant A. baumannii infections via drug repurposing

We evaluated in vitro activity of 13 drugs used in the treatment of some non-communicable diseases via repurposing to determine their potential use in the treatment of Acinetobacter baumannii infections caused by susceptible and multidrug-resistant strains. A. baumannii is a multidrug-resistant Gram-negative bacteria causing nosocomial infections, especially in intensive care units. It has been identified in the WHO critical pathogen list and this emphasises urgent need for new treatment options. As the development of new therapeutics is expensive and time consuming, finding new uses of existing drugs via drug repositioning has been favoured. Antimicrobial susceptibility tests were conducted on all 13 drugs according to CLSI. Drugs with MIC values below 128 μg/mL and control antibiotics were further subjected to synergetic effect and bacterial time-kill analysis. Carvedilol-gentamicin (FICI 0.2813) and carvedilol-amlodipine (FICI 0.5625) were determined to have synergetic and additive effect, respectively, on the susceptible A. baumannii strain, and amlodipine-tetracycline (FICI 0.75) and amitriptyline-tetracycline (FICI 0.75) to have additive effect on the multidrug-resistant A. baumannii strain. Most remarkably, both amlodipine and amitriptyline reduced the MIC of multidrug-resistant, including some carbapenems, A. baumannii reference antibiotic tetracycline from 2 to 0.5 μg/mL, for 4-folds. All these results were further supported by bacterial time-kill assay and all combinations showed bactericidal activity, at certain hours, at 4XMIC. Combinations proposed in this study may provide treatment options for both susceptible and multidrug-resistant A. baumannii infections but requires further pharmacokinetics and pharmacodynamics analyses and in vivo re-evaluations using appropriate models.

In vitro and in vivo activity of meropenem+avibactam against MBL-producing carbapenem-resistant Klebsiella pneumoniae

BACKGROUND

Antibiotic resistance has become a public health problem to be solved worldwide and metallo-β-lactamase (MBL)-producing bacteria make this problem even more challenging.

METHODS

The interactions of meropenem (MEM) in combination with avibactam (AVI) in growth inhibition on MBL-producing carbapenem-resistant Klebsiella pneumoniae (CRKP) strains were tested. In vitro interactions of MEM+AVI were tested using the microdilution checkerboard assay and time-kill curves. In vivo interactions of MEM+AVI were tested using the Galleria mellonella model.

RESULTS

All strains were multi-drug resistant strains and six of them were proved to produce MBLs. We show that the combination of MEM+AVI generates profound synergistic effects on growth inhibition of all strains, which was better than that of MEM+vaborbactam or imipenem+relebactam. The time-kill curves further confirmed the potent synergistic antibacterial effects of MEM+AVI against MBL-producing CRKP strains. Galleria mellonella studies were consistent with in vitro analysis. Combining MEM with AVI improved survival rates and mean survival days were obviously prolonged compared to the drug alone and the untreated controls.

CONCLUSIONS

To our knowledge, this study is the first report of MEM+AVI collaborating against MBL-producing CRKP strains. Our findings showed that the combination of MEM+AVI has the potential for antibiotic drug development to combat MBL-producing pathogens.

The application of ambroxol hydrochloride combined with fiberoptic bronchoscopy in elderly patients with severe pneumonia: A meta-analysis and systematic review

BACKGROUND

The role of ambroxol hydrochloride combined with fiberoptic bronchoscopy in elderly patients with severe pneumonia remains unclear, we aimed to analyze this issue to provide evidences into the management of clinical pneumonia.

METHODS

We searched PubMed et al databases up to October 20, 2021 for the randomized controlled trials on the application of ambroxol hydrochloride combined with fiberoptic bronchoscopy in elderly patients with severe pneumonia. Related outcomes were extracted and analyzed. Review Manager 5.3 software was used for data analysis.

RESULTS

A total of 13 randomized controlled trials involving 1317 elderly patients (559 cases in the ambroxol hydrochloride + fiberoptic bronchoscopy group and 658 cases in the fiberoptic bronchoscopy group) with pneumonia were included. Meta-analyses indicated that the blood oxygen partial pressure [mean difference (MD) = 5.75, 95% confidence interval (CI) (3.80, 7.70)], blood oxygen saturation [MD = 6.43, 95% CI (4.39, 8.48)], oxygenation index [MD = 26.75, 95% CI (14.61, 38.89)] of experimental group was significantly higher than that of control group (all P < .001), the incidence of multiple organ failure [odds ratio = 0.42, 95% CI (0.31, 0.56), P < .001], mortality on day 28 [odds ratio = 0.44, 95% CI (0.33, 0.59)] of experimental group was significantly less than that of control group (all P < .001).

CONCLUSIONS

The high-dose ambroxol hydrochloride combined with fiberoptic bronchoscopy is beneficial to improve the patient's blood gas indicators, and reduce mortality in elderly patients with severe pneumonia.