Current Bacteriology of Suppurative Otitis

Saunders, James E.; Raju, Ryan; Boone, Jonathan D.; Berryhill, Wayne E.

doi:10.1097/mao.0b013e3181977b6e

Cited by 17 publications

(2 citation statements)

References 12 publications

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“…P. aeruginosa resistance to quinolones has been documented to be as high as 18% in suppurative otitis [6] and this coupled with recent evidence of P. aeruginosa biofilm formation in otology [7,8] could explain many treatment failures. Biofilm formation may sustain the inflammatory response that promotes persistent drainage from the ear [9,10].…”

Section: Introductionmentioning

confidence: 99%

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

Lea

Conlin

Sekirov

et al. 2014

Journal of Otolaryngology - Head & Neck Surgery

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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.

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Section: Introductionmentioning

confidence: 99%

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

Lea

Conlin

Sekirov

et al. 2014

Journal of Otolaryngology - Head & Neck Surgery

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“…However, treatment failures with ototopical fluoroquinolones continue to be a problem and the role of bacterial resistance is debated. Treatment failures in aural infections correlate with resistant bacterial isolates, and previous use of ototopical fluoroquinolones is associated with resistance (7,16,18,(27)(28)(29). Because of their widespread use, fluoroquinolone resistance has steadily risen along with increasing concern about the impact of resistance on ototopical therapy (30)(31)(32)(33).…”

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confidence: 99%

Characterization of Ciprofloxacin Resistance Levels: Implications for Ototopical Therapy

Trinh¹,

Ruoff

Rees³

et al. 2021

Otology &Amp; Neurotology

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Hypothesis:Ciprofloxacin-resistant pathogens are inhibited by high concentrations of ciprofloxacin found in commercially-available ototopical solutions.Background:Ciprofloxacin-resistant pathogens in otitis media are currently treated with ototopical ciprofloxacin suspensions. This is done irrespective of laboratory-reported ciprofloxacin susceptibility, under the assumption that the high concentration of ciprofloxacin applied topically is sufficient to overcome antimicrobial resistance.Methods:We evaluated 34 ciprofloxacin-resistant isolates consisting of Staphylococcus aureus, Pseudomonas aeruginosa, Corynebacterium spp., and Turicella otitidis. Ciprofloxacin minimum inhibitory concentration (MIC) assays and clinical ototopical solution minimum bactericidal concentration (CMBC) assays were performed.Results:Amongst the ciprofloxacin-resistant isolates, ciprofloxacin MICs ranged from 8 to 256 mcg/ml (mean: 87.1 mcg/ml) and CMBCs ranged from 23.4 to 1500 mcg/ml (mean: 237.0 mcg/ml). There were no significant differences with respect to MIC in comparing P. aeruginosa versus Corynebacterium spp. (mean: 53.3 versus 55.2, p = 0.86), S. aureus versus P. aeruginosa (mean: 128.0 versus 53.3, p = 0.34), and S. aureus versus Corynebacterium spp. (mean: 128.0 versus 55.2, p = 0.09). The correlation between ciprofloxacin MIC and CMBC was poor (Pearson's r = –0.08, p = 0.75).Conclusions:Ciprofloxacin-resistant pathogens commonly recovered from otitis media exhibit highly variable ciprofloxacin MIC and CMBC levels. Ciprofloxacin was able to inhibit growth in all isolates tested at MIC levels less than or equal to 256 mcg/ml; however, CMBC's up to 1500 mcg/ml were observed within that same group. The clinical relevance of these in vitro MICs is unclear due in part to higher bactericidal concentrations (CMBC) in several strains. Our results suggest that treatment failures may be due to a combination of factors rather than high-level resistance alone.

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Methicillin‐resistant and methicillin‐sensitive Staphylococcus aureus laryngitis

Shah

Klein

2012

The Laryngoscope

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Current Bacteriology of Suppurative Otitis

Abstract: Previous antibiotic use is correlated with increased bacterial resistance in the case of otitis externa. Highly resistant bacteria were associated with an increased rate of treatment failure. Culture plays an essential role in the management of refractory otorrhea.

Cited by 17 publications

References 12 publications

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

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

Characterization of Ciprofloxacin Resistance Levels: Implications for Ototopical Therapy

Methicillin‐resistant and methicillin‐sensitive Staphylococcus aureus laryngitis

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