Differences in bacteriologic treatment failures in acute otitis externa between ciprofloxacin/dexamethasone and neomycin/polymyxin B/hydrocortisone: results of a combined analysis

[The species composition and sensitivity of pathogenic microflora responsible for the development of otitis externa diffusa to the components of Polidexa]

The objective of the present work was to study microflora of the external auditory meatus in the patients presenting with bacterial otitis externa diffusa. The authors have analyzed the results of microbiological investigations involving 102 patients with this condition undergoing the treatment with 'Polidexa'. The characteristic of species composition of microflora associated with otitis externa diffusa is presented. The sensitivity of the most common pathogens responsible for the development of this pathology towards antibiotics contained in ear drops has been analysed. The advantages of the use Polidexa for the treatment of this acute ear disease are described.

Anti-biofilm activity of pseudoalteromonas haloplanktis tac125 against staphylococcus epidermidis biofilm: Evidence of a signal molecule involvement?

Staphylococcus epidermidis is recognized as cause of biofilm-associated infections and interest in the development of new approaches for S. epidermidis biofilm treatment has increased. In a previous paper we reported that the supernatant of Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 presents an anti-biofilm activity against S. epidermidis and preliminary physico-chemical characterization of the supernatant suggested that this activity is due to a polysaccharide. In this work we further investigated the chemical nature of the anti-biofilm P. haloplanktis TAC125 molecule. The production of the molecule was evaluated in different conditions, and reported data demonstrated that it is produced in all P. haloplanktis TAC125 biofilm growth stages, also in minimal medium and at different temperatures. By using a surface coating assay, the surfactant nature of the anti-biofilm compound was excluded. Moreover, a purification procedure was set up and the analysis of an enriched fraction demonstrated that the anti-biofilm activity is not due to a polysaccharide molecule but that it is due to small hydrophobic molecules that likely work as signal. The enriched fraction was also used to evaluate the effect on S. epidermidis biofilm formation in dynamic condition by BioFlux system.

Dexamethasone modulation of MUC5AC and MUC2 gene expression in a generalized model of middle ear inflammation

OBJECTIVES/HYPOTHESIS

To examine the effect of dexamethasone on basal and proinflammatory cytokine-induced gel-forming mucin expression in human middle ear epithelial cell line (HMEEC-1).

METHODS

HMEEC-1 was exposed to proinflammatory cytokines, tumor necrosis factor-alpha (TNF-), and interleukin-1 beta (IL-1β) to identify optimal mucin induction. The HMEEC-1 was incubated with dexamethasone in the steady state and in the presence of proinflammatory cytokine stimulation. Expression of MUC2 and MUC5AC was determined by quantitative polymerase chain reaction.

RESULTS

Proinflammatory cytokines, TNF-α and IL-1β, induced MUC2 and MUC5AC expression in HMEEC-1. Dexamethasone reduced steady state mRNA level of MUC5AC in a time-dependent (P < 0.05) and dose-dependent (P < 0.0001) manner. MUC2 was effectively suppressed at all time points tested (P < 0.05). Temporal difference between dexamethasone suppression of MUC2 and MUC5AC was demonstrated. Dexamethasone inhibits the proinflammatory cytokine-induced expression of both MUC2 and MUC5AC.

CONCLUSION

This work provides a conclusive picture of the ability of using glucocorticoids to downregulate mucin gene expression in human MEE using a generalizable model of inflammation that is applicable to multiple potential causes of MEE mucosal hypertrophy. This data adds to the promising potential of future interventions for patients with chronic otitis media.

LEVEL OF EVIDENCE

N/A. Laryngoscope, 126:E248-E254, 2016.

Development and validation of an Haemophilus influenzae supragenome hybridization (SGH) array for transcriptomic analyses

We previously carried out the design and testing of a custom-built Haemophilus influenzae supragenome hybridization (SGH) array that contains probe sequences to 2,890 gene clusters identified by whole genome sequencing of 24 strains of H. influenzae. The array was originally designed as a tool to interrogate the gene content of large numbers of clinical isolates without the need for sequencing, however, the data obtained is quantitative and is thus suitable for transcriptomic analyses. In the current study RNA was extracted from H. influenzae strain CZ4126/02 (which was not included in the design of the array) converted to cDNA, and labelled and hybridized to the SGH arrays to assess the quality and reproducibility of data obtained from these custom-designed chips to serve as a tool for transcriptomics. Three types of experimental replicates were analyzed with all showing very high degrees of correlation, thus validating both the array and the methods used for RNA profiling. A custom filtering pipeline for two-condition unpaired data using five metrics was developed to minimize variability within replicates and to maximize the identification of the most significant true transcriptional differences between two samples. These methods can be extended to transcriptional analysis of other bacterial species utilizing supragenome-based arrays.

Ciprofloxacin plus fluocinolone acetonide versus ciprofloxacin alone in the treatment of diffuse otitis externa

OBJECTIVE

We aimed to evaluate the clinical efficacy of ciprofloxacin plus fluocinolone acetonide (antibiotic plus corticosteroid) ear drops compared to ciprofloxacin (antibiotic) ear drops in diffuse otitis externa.

METHODS

This was a multicentre, randomised, parallel-group, double-blind study involving 590 patients of both sexes aged 7 years or older.

RESULTS

The rate of clinical cure was higher (p = 0.01) with ciprofloxacin plus fluocinolone acetonide than with ciprofloxacin alone. The mean total symptom score was lower with ciprofloxacin plus fluocinolone acetonide (p = 0.005). No differences were found in the percentage of patients reporting resolution of otalgia between patients receiving ciprofloxacin plus fluocinolone acetonide and patients receiving only ciprofloxacin. Resolution of oedema and otorrhoea (p = 0.003 and p = 0.002, respectively) was higher with ciprofloxacin plus fluocinolone acetonide, as was eradication or presumed eradication (p = 0.003). There were eight mild adverse events, three with the ciprofloxacin plus fluocinolone acetonide combination (not related to the treatment) and five when ciprofloxacin was administered alone (directly related to the treatment).

CONCLUSIONS

Ciprofloxacin plus fluocinolone acetonide is a more effective treatment for diffuse otitis externa than ciprofloxacin alone. The ciprofloxacin plus fluocinolone acetonide combination also has an excellent safety profile.

New information about the polymyxin/colistin class of antibiotics

Infections by multidrug resistant Gram-negative bacilli (MDR-GNB) have become a major threat for patients hospitalized in intensive care units, representing a prevalent cause of morbimortality in the critically ill, since these microorganisms have developed resistance to most available antimicrobial agents. In this respect, very few therapeutic innovations have been developed in recent years, and it is not foreseen that any new drugs will be commercialized in the near future. Tigecycline represents an effective alternative in this setting, but lacks activity against Pseudomonas aeruginosa, and its use has not been validated for all organ-specific infections. Frequently, only old antibiotics like colistin remain a valid option. New pharmaceutical formulations and dosage regimens of polymyxins have considerably reduced the toxicity previously attributed to these antimicrobials, and have made it possible to reintroduce them into clinical practice. Nonetheless, the effectiveness of polymyxins is still suboptimal, and the expansion of heteroresistance and pan-drug-resistant strains of gram-negative bacilli is of concern. Improvements in dosing, alternative methods of administration and different synergic antimicrobial combinations have been proposed in recent literature, among other measures, to enhance the effectiveness of polymyxins. The latest data regarding polymyxins and their clinical use are discussed in this review.