Effects of topical chlorhexidine applied to the rabbit nasal mucosa

Sinonasal Stent Coated with Slow-Release Varnish of Chlorhexidine Has Sustained Protection against Bacterial Biofilm Growth in the Sinonasal Cavity: An In Vitro Study

The aim of the study was to develop a sustained-release varnish (SRV) containing chlorhexidine (CHX) for sinonasal stents (SNS) to reduce bacterial growth and biofilm formation in the sinonasal cavity. Segments of SNS were coated with SRV-CHX or SRV-placebo and exposed daily to bacterial cultures of Staphylococcus aureus subsp. aureus ATCC 25923 or Pseudomonas aeruginosa ATCC HER-1018 (PAO1). Anti-bacterial effects were assessed by disc diffusion assay and planktonic-based activity assay. Biofilm formation on the coated stents was visualized by confocal laser scanning microscopy (CLSM) and high-resolution scanning electron microscopy (HR-SEM). The metabolic activity of the biofilms was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) method. Disc diffusion assay showed that SRV-CHX-coated SNS segments inhibited bacterial growth of S. aureussubsp. aureus ATCC 25923 for 26 days and P. aeruginosa ATCC HER-1018 for 19 days. CHX was released from coated SNS segments in a pH 6 medium up to 30 days, resulting in growth inhibition of S. aureussubsp. aureus ATCC 25923 for 22 days and P. aeruginosa ATCC HER-1018 for 24 days. The MTT assay showed a reduction of biofilm growth on the coated SNS by 69% for S. aureussubsp. aureus ATCC 25923 and 40% for P. aeruginosa ATCC HER-1018 compared to the placebo stent after repeated exposure to planktonic growing bacteria. CLSM and HR-SEM showed a significant reduction of biofilm formation on the SRV-CHX-coated SNS segments. Coating of SNS with SRV-CHX maintains a sustained delivery of CHX, providing an inhibitory effect on the bacterial growth of S. aureussubsp. aureus ATCC 25923 and P. aeruginosa ATCC HER-1018 for approximately 3 weeks.

Comparative study of the efficacy of topical steroid and antibiotic combination therapy versus oral antibiotic alone when treating acute rhinosinusitis

Background:

Acute rhinosinusitis arises as a consequence of viral rhinitis, and bacterial infection can subsequently occur. Intranasal antibiotics as an adjunct to corticosteroids usually demonstrate the greatest symptom relief.

Aim:

We wanted to clinically evaluate the effects of a topical antibiotic and steroid combination administered intranasally, versus an oral antibiotic alone when treating acute rhinosinusitis.

Method:

Forty patients with acute bacterial rhinosinusitis were divided into two groups. Group A received an antibiotic and steroid combination (ofloxacin 0.26 per cent and dexamethasone 0.053 per cent nasal drops) for 10 days, administered intranasally (5 drops in each nostril/8 hours). Group B, the control group, received an oral antibiotic alone (amoxicillin 90 mg/kg).

Results:

Eight hours after commencing treatment, facial pain was more severe in group B and nasal obstruction was reduced in both groups. Ten days after commencing treatment, anterior nasal discharge was 0.15 per cent in group A and absent in group B.

Conclusion:

The application of a topical antibiotic and steroid combination into the nasal cavity is an effective way of treating uncomplicated, acute bacterial rhinosinusitis with the theoretical advantages of easy administration, high local drug concentration and minimal systemic adverse effects.

Use of the probiotic Lactobacillus plantarum 299 to reduce pathogenic bacteria in the oropharynx of intubated patients: a randomised controlled open pilot study

Introduction

Ventilator-associated pneumonia (VAP) is usually caused by aspiration of pathogenic bacteria from the oropharynx. Oral decontamination with antiseptics, such as chlorhexidine (CHX) or antibiotics, has been used as prophylaxis against this complication. We hypothesised that the probiotic bacteria Lactobacillus plantarum 299 (Lp299) would be as efficient as CHX in reducing the pathogenic bacterial load in the oropharynx of tracheally intubated, mechanically ventilated, critically ill patients.

Methods

Fifty critically ill patients on mechanical ventilation were randomised to either oral mechanical cleansing followed by washing with 0.1% CHX solution or to the same cleansing procedure followed by oral application of an emulsion of Lp299. Samples for microbiological analyses were taken from the oropharynx and trachea at inclusion and at defined intervals thereafter.

Results

Potentially pathogenic bacteria that were not present at inclusion were identified in oropharyngeal samples from eight of the patients treated with Lp299 and 13 of those treated with CHX (p = 0.13). Analysis of tracheal samples yielded similar results. Lp299 was recovered from the oropharynx of all patients in the Lp299 group.

Conclusions

In this pilot study, we found no difference between the effect of Lp299 and CHX used in oral care procedures, when we examined the effects of those agents on colonisation of potentially pathogenic bacteria in the oropharynx of intubated, mechanically ventilated patients.

Effects of Single Intratracheal Exposure to Chlorhexidine Gluconate on the Rat Lung

Chlorhexidine gluconate (CHX) is an antiseptic that has been widely used for disinfection of cutaneous wound and gingivae. Recently, a patient who inhaled CHX solution died from acute respiratory distress syndrome (ARDS). Although it is highly possible that direct pulmonary damage might be the cause of ARDS, there is no preclinical information about the pulmonary toxicity of CHX. In the current study, the acute direct action of CHX to the lung was evaluated in rats. We successfully exposed the left but not the right lung either to CHX at concentrations of 1%, 0.1%, and 0.01% or to saline using a curved-tip administration tube. At the higher concentrations of CHX (0.1% and 1%), severe congestion to the alveoli and capillaries and perivascular and intra-alveolar hemorrhages were observed 1 day after exposure. Aniline blue-stained collagen fibers with an infiltration of inflammatory cells were present 7 days after exposure. The fibrotic changes and intra-alveolar inflammatory cells had decreased but were still observed sporadically 28 and 84 days after exposure. These detrimental effects were more severe at 1% than at 0.1% CHX. No remarkable effect was observed after exposures to 0.01% CHX and saline. We were able to evaluate the time-course changes in the pulmonary toxicity of CHX by exposures limited to the left lung. It is highly possible that CHX at a concentration of more than 0.1% might directly induce ARDS when aspirated and reaching to the alveoli.

Local irritant effects of topical oral sprays on oral mucosa in mice

Topical oral sprays are frequently used to prevent and manage oropharyngeal inflammation and lesions. This study investigated the histopathologic changes noted in the oral mucosa of mice after topical application of 3 widely prescribed antibacterial products. The 25 animals were divided into 5 groups and treated for 10 days with 2 sprays daily, as follows: group 1-chlorhexidine gluconate 0.12% + benzydamine hydrochloride 0.15%; group 2-benzydamine 0.27 mg/0.18 mL x 30 mL; group 3-chlorhexidine 0.2%; group 4-fusafungine 1%; and group 5 (cohort)-physiologic serum. On day 10 after drug administration, biopsy specimens were taken from the oropharyngeal mucosa of the tongue, the cheek mucosa, and the tongue base; these were examined under a light microscope and were classified as normal or pathologic. All topical oral sprays produced some degree of histopathologic change, such as hyperplasia, fibrosis, low-grade dysplasia, congestion, or edema. The local irritant effects of topical oral sprays should be considered when treatment is selected for patients with oropharyngeal disorder.