In vitro efficacy of N-acetylcysteine on bacteria associated with chronic suppurative otitis media

Abstract

BackgroundThe safety and efficacy of Ciprodex® has been demonstrated for treatment of chronic suppurative otitis media (CSOM). However, symptoms fail to resolve in 9-15% of patients. The objective of this study is to evaluate the efficacy of N-acetylcysteine (NAC) on S. aureus, and planktonic and sessile (biofilm forming) P. aeruginosa in vitro using clinical isolates from patients with CSOM.Methods1) Stability was assessed using liquid chromatography-mass spectrometry for each component in a prepared mixture of Ciprodex® and NAC over 15 days. Sterility was assessed by measuring bacterial growth on a blood agar plate. Efficacy was assessed using a disc diffusion method by inoculating plates with S. aureus ATCC 29513 and P. aeruginosa ATCC 27853, and measuring the clearance zone.2) Fifteen P. aeruginosa strains were isolated from patients with CSOM and tested in vitro using the bioFILM PA™ antimicrobial susceptibility assay. Treatment solutions included Ciprodex® & ciprofloxacin +/- NAC, and NAC alone (0.25%, 0.5% & 1.25%).Results1) NAC combined with Ciprodex® demonstrated stability, sterility, and efficacy over a two-week period2) P. aeruginosa strains in the sessile (33%-40%) and planktonic (13%) state demonstrated resistance to Ciprodex® and ciprofloxacin. When NAC ≥0.5% was used in isolation or as an adjunct to either of these medications, no resistance was found in the sessile or planktonic state among all 15 strains.Conclusion1) Ciprodex® combined with NAC has a shelf life of at least two weeks given the documented preservation of stability, sterility, and clinical efficacy of the mixed compounds.2) P. aeruginosa strains demonstrated resistance to both Ciprodex® and ciprofloxacin. NAC ≥0.5% overcomes issues with resistance and shows promise in the treatment of CSOM.

In vitroantimicrobial activity of seven adjuvants against common pathogens associated with canine otitis externa

“…Conversely, an older study observed that P. aeruginosa growth curve and inhibition in the presence of NAC were both dose‐ and inoculum size‐dependent; consequently, they were able to detect a NAC MIC of P. aeruginosa at a lower concentration range (2–20 μg/mL). Another study used NAC as an adjunctive therapy against fluoroquinolone/ciprofloxacin‐resistant P. aeruginosa strains associated with human chronic otitis media at concentrations ≥0.5% or 5,000 μg/mL . Taken together, our results and those from previous studies suggest that NAC could potentially be a useful antimicrobial adjuvant that could be safely incorporated in the treatment and management of OE in dogs, especially in cases associated with antimicrobial resistance.…”

The effect of N -acetylcysteine on biofilms: Implications for the treatment of respiratory tract infections

“…biofilm-associated respiratory tract infections. In particular, Lea and colleagues [36] evaluated the effects of ciprofloxacin alone, ciprofloxacin + dexamethasone, NAC alone, and NAC + ciprofloxacin on 15 strains of P. aeruginosa isolated from patients with suppurative otitis media. While P. aeruginosa strains grew in the presence of ciprofloxacin + dexamethasone and ciprofloxacin alone, no growth was found in the sessile or planktonic state among all 15 strains when NAC (≥ 5 mg/ml) was used either alone or in combination with ciprofloxacin.…”

Efficiency of Propolis and N-acetylcisteine on Reduction in Symptom Severity of Respiratory Infection in Children with Adenoid Hypertrophy

“…It is considered that NAC has multiple inhibitory effects on biofilm formation; it has an effect on bacteria adhesion to the surface, matrix production and architecture as well as on the pre-formed biofilms spreading. After Peres-Giraldo et al first described antibiofilm activity, by examining the effect that NAC has on Staphylococcus epidermidis, a number of studies followed, proving such activity in a number of gram-positive and gram-negative bacteria [10][11][12]. Although in-vitro studies provide strong arguments that NAC can disrupt biofilm, clinical data are still being collected.…”