Effect of High N-Acetylcysteine Concentrations on Antibiotic Activity against a Large Collection of Respiratory Pathogens.

Giulia Landini,Francesco Sergio,Gian Maria Rossolini,Jean-Denis Docquier,Lucia Pallecchi,Tiziana Di Maggio

doi:10.1128/aac.01334-16

Giulia Landini, Francesco Sergio + Show 4 more

Open Access

https://doi.org/10.1128/aac.01334-16

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Abstract

The effect of high N-acetylcysteine (NAC) concentrations (10 and 50 mM) on antibiotic activity against 40 strains of respiratory pathogens was investigated. NAC compromised the activity of carbapenems (of mostly imipenem and, to lesser extents, meropenem and ertapenem) in a dose-dependent fashion. We demonstrated chemical instability of carbapenems in the presence of NAC. With other antibiotics, 10 mM NAC had no major effects, while 50 mM NAC sporadically decreased (ceftriaxone and aminoglycosides) or increased (penicillins) antibiotic activity.

Highlights

The effect of high N-acetylcysteine (NAC) concentrations (10 and 50 mM) on antibiotic activity against 40 strains of respiratory pathogens was investigated
Discordant results were recently reported from two studies that investigated the effect of 10 mM NAC (i.e., 1.6 mg/ml) on the activity of some antibiotics against a few Gram-negative pathogens
The modulatory effects observed by Goswami et al [10] were not confirmed by Rodríguez-Beltrán et al [11], who demonstrated that the modulation of the activity of fluoroquinolones and aminoglycosides was related to the low pH of pure NAC powder solutions and not to NAC itself, suggesting that pH-related issues likely contributed to the inconsistency of data from previous studies

Summary

Introduction

The effect of high N-acetylcysteine (NAC) concentrations (10 and 50 mM) on antibiotic activity against 40 strains of respiratory pathogens was investigated. Discordant results were recently reported from two studies that investigated the effect of 10 mM NAC (i.e., 1.6 mg/ml) on the activity of some antibiotics against a few Gram-negative pathogens (including Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Acinetobacter baumannii). The stability of 200 ␮M imipenem, meropenem, and ertapenem solutions in the absence or presence of NAC was investigated in phosphate-buffered saline (PBS) (pH 7.4) at 25°C and 37°C and in cation-adjusted Mueller-Hinton broth (CAMHB) at 37°C.

Results

Conclusion