Topical Chlorhexidine Research Articles

Patients with Long-Term Oral Carriage Harbor High-Persister Mutants of Candida albicans

Fungal biofilms produce a small number of persister cells which can tolerate high concentrations of fungicidal agents. Persisters form upon attachment to a surface, an important step in the pathogenesis of Candida strains. The periodic application of antimicrobial agents may select for strains with increased levels of persister cells. In order to test this possibility, 150 isolates of Candida albicans and C. glabrata were obtained from cancer patients who were at high risk for the development of oral candidiasis and who had been treated with topical chlorhexidine once a day. Persister levels were measured by exposing biofilms growing in the wells of microtiter plates to high concentrations of amphotericin B and plating for survivors. The persister levels of the isolates varied from 0.2 to 9%, and strains isolated from patients with long-term carriage had high levels of persisters. High-persister strains were isolated from every patient with Candida carriage of more than 8 consecutive weeks but from no patients with transient carriage. All of the high-persister isolates had an amphotericin B MIC that was the same as that for the wild type, indicating that these strains were drug-tolerant rather than drug-resistant mutants. Biofilms of the majority of high-persister strains also showed an increased tolerance to chlorhexidine and had the same MIC for this antimicrobial as the wild type. This study suggests that persister cells are clinically relevant, and antimicrobial therapy selects for high-persister strains in vivo. The drug tolerance of persisters may be a critical but overlooked component responsible for antimicrobial drug failure and relapsing infections.

Chlorhexidine, Toothbrushing, and Preventing Ventilator-Associated Pneumonia in Critically Ill Adults

Ventilator-associated pneumonia is associated with increased morbidity and mortality. To examine the effects of mechanical (toothbrushing), pharmacological (topical oral chlorhexidine), and combination (toothbrushing plus chlorhexidine) oral care on the development of ventilator-associated pneumonia in critically ill patients receiving mechanical ventilation. Critically ill adults in 3 intensive care units were enrolled within 24 hours of intubation in a randomized controlled clinical trial with a 2 x 2 factorial design. Patients with a clinical diagnosis of pneumonia at the time of intubation and edentulous patients were excluded. Patients (n = 547) were randomly assigned to 1 of 4 treatments: 0.12% solution chlorhexidine oral swab twice daily, toothbrushing thrice daily, both toothbrushing and chlorhexidine, or control (usual care). Ventilator-associated pneumonia was determined by using the Clinical Pulmonary Infection Score (CPIS). The 4 groups did not differ significantly in clinical characteristics. At day 3 analysis, 249 patients remained in the study. Among patients without pneumonia at baseline, pneumonia developed in 24% (CPIS >or=6) by day 3 in those treated with chlorhexidine. When data on all patients were analyzed together, mixed models analysis indicated no effect of either chlorhexidine (P = .29) or toothbrushing (P = .95). However, chlorhexidine significantly reduced the incidence of pneumonia on day 3 (CPIS >or=6) among patients who had CPIS <6 at baseline (P = .006). Toothbrushing had no effect on CPIS and did not enhance the effect of chlorhexidine. Chlorhexidine, but not toothbrushing, reduced early ventilator-associated pneumonia in patients without pneumonia at baseline.

Dermatomycosis in a pet inland bearded dragon (Pogona vitticeps) caused by a Chrysosporium species related to Nannizziopsis vriesii

A Chrysosporium sp. related to Nannizziopsis vriesii was isolated in pure culture from squames and biopsies of facial lesions in a pet inland bearded dragon (Pogona vitticeps) in Spain. The presence in histological sections of morphologically consistent fungal elements strongly incriminates this fungus as the aetiological agent of infection. Lesions regressed following treatment with oral ketoconazole and topical chlorhexidine and terbinafine until the lizard was lost to follow up 1 month later. The ITS-5.8S rRNA gene of the isolate was sequenced and a search on the GenBank database revealed a high match with the sequences of two Chrysosporium sp. strains recently isolated from green iguanas (Iguana iguana) with dermatomycosis, also in Spain. Phylogenetic analysis of the sequences revealed that all these strains are related to N. vriesii. This is the first report of dermatomycoses caused by a Chrysosporium species related to N. vriesii in a bearded dragon outside North America.

Persistence of Extracrevicular Bacterial Reservoirs After Treatment of Aggressive Periodontitis

The purpose of this study was to test the hypothesis that periodontal pathogens associated with aggressive periodontitis persist in extracrevicular locations following scaling and root planing, systemic antibiotics, and antimicrobial rinses. Eighteen patients with aggressive periodontitis received a clinical examination during which samples of subgingival plaque and buccal epithelial cells were obtained. Treatment consisted of full-mouth root planing, systemic antibiotics, and chlorhexidine rinses. Clinical measurements and sampling were repeated at 3 and 6 months. Quantitative polymerase chain reaction determined the number of Aggregatibacter actinomycetemcomitans (previously Actinobacillus actinomycetemcomitans), Prevotella intermedia, Porphyromonas gingivalis, Tannerella forsythia (previously T. forsythensis), and Treponema denticola in the plaque. Fluorescence in situ hybridization and confocal microscopy determined the extent of intracellular invasion in epithelial cells. Clinical measurements improved significantly following treatment. All bacterial species except P. gingivalis were significantly reduced in plaque between baseline and 3 months. However, all species showed a trend to repopulate between 3 and 6 months. This increase was statistically significant for log T. denticola counts. All species were detected intracellularly. The percentage of cells infected intracellularly was not affected by therapy. The 6-month increasing trend in the levels of plaque bacteria suggests that subgingival recolonization was occurring. Because the presence of these species within epithelial cells was not altered after treatment, it is plausible that recolonization may occur from the oral mucosa. Systemic antibiotics and topical chlorhexidine did not reduce the percentage of invaded epithelial cells. These data support the hypothesis that extracrevicular reservoirs of bacteria exist, which might contribute to recurrent or refractory disease in some patients.

Newborn umbilical cord and skin care in Sylhet District, Bangladesh: implications for the promotion of umbilical cord cleansing with topical chlorhexidine

Newborn cord care practices may directly contribute to infections, which account for a large proportion of the four million annual global neonatal deaths. This formative research study assessed current umbilical and skin care knowledge and practices for neonates in Sylhet District, Bangladesh, in preparation for a cluster-randomized trial of the impact of topical chlorhexidine cord cleansing on neonatal mortality and omphalitis. Unstructured interviews (n=60), structured observations (n=20), rating and ranking exercises (n=40) and household surveys (n=400) were conducted to elicit specific behaviors regarding newborn cord and skin care practices. These included hand-washing, skin and cord care at the time of birth, persons engaged in cord care, cord cutting practices, topical applications to the cord at the time of birth, wrapping/dressing of the cord stump and use of skin-to-skin care. Overall 90% of deliveries occurred at home. The umbilical cord was almost always (98%) cut after delivery of the placenta, and cut by mothers in more than half the cases (57%). Substances were commonly (52%) applied to the stump after cord cutting; turmeric was the most common application (83%). Umbilical stump care revolved around bathing, skin massage with mustard oil and heat massage on the umbilical stump. Overall 40% of newborns were bathed on the day of birth. Mothers were the principal provider for skin and cord care during the neonatal period and 9% of them reported umbilical infections in their infants. Unhygienic cord care practices are prevalent in the study area. Efforts to promote hand-washing, cord cutting with clean instruments and avoiding unclean home applications to the cord may reduce exposure and improve neonatal outcomes. Such efforts should broadly target a range of caregivers, including mothers and other female household members.

Poster 56: Pneumonias in Tracheostomy Patients: Does Topical Oral Chlorhexidine Decrease Incidence During Inpatient Rehabilitation?

Objective: To evaluate the effects of chlorhexidine, demographic variables, dysphagia, and their interaction on pneumonia incidence and resultant discharge destination in patients admitted to inpatient rehabilitation with tracheostomies. Design: Retrospective case-control study. Setting: Freestanding acute inpatient rehabilitation facility. Participants: 226 subjects admitted with tracheostomies over a 1-year period (2006). Interventions: All medical records of patients admitted to inpatient rehabilitation with a tracheostomy and discharged in 2006 were reviewed.

Breast-Feeding Patterns, Time to Initiation, and Mortality Risk among Newborns in Southern Nepal

Initiation of breast-feeding within 1 h after birth has been associated with reduced neonatal mortality in a rural Ghanaian population. In South Asia, however, breast-feeding patterns and low birth weight rates differ and this relationship has not been quantified. Data were collected during a community-based randomized trial of the impact of topical chlorhexidine antisepsis interventions on neonatal mortality and morbidity in southern Nepal. In-home visits were conducted on d 1–4, 6, 8, 10, 12, 14, 21, and 28 to collect longitudinal information on timing of initiation and pattern of breast-feeding. Multivariable regression modeling was used to estimate the association between death and breast-feeding initiation time. Analysis was based on 22,838 breast-fed newborns surviving to 48 h. Within 1 h of birth, 3.4% of infants were breast-fed and 56.6% were breast-fed within 24 h of birth. Partially breast-fed infants (72.6%) were at higher mortality risk [relative risk (RR) = 1.77; 95% CI = 1.32–2.39] than those exclusively breast-fed. There was a trend (P = 0.03) toward higher mortality with increasing delay in breast-feeding initiation. Mortality was higher among late (≥24 h) compared with early (<24 h) initiators (RR = 1.41; 95% CI = 1.08–1.86) after adjustment for low birth weight, preterm birth, and other covariates. Improvements in breast-feeding practices in this setting may reduce neonatal mortality substantially. Approximately 7.7 and 19.1% of all neonatal deaths may be avoided with universal initiation of breast-feeding within the first day or hour of life, respectively. Community-based breast-feeding promotion programs should remain a priority, with renewed emphasis on early initiation in addition to exclusiveness and duration of breast-feeding.

Acanthamoeba Keratitis

To report a non-contact lens wearer with persistent Acanthamoeba organisms in the cornea after being treated with medical therapy that included topical chlorhexidine as 1 agent for 1 year. A 53-year-old man with Acanthamoeba keratitis was treated with medical therapy for >1 year, followed by a penetrating keratoplasty. Histopathologic examination of the keratoplasty specimen revealed viable-appearing Acanthamoeba cysts and trophozoites within the deep corneal stroma in a focus of corneal scarring. The use of chlorhexidine as 1 agent in the medical management of Acanthamoeba keratitis may not eradicate the organisms.

Topical chlorhexidine and ventilator-associated pneumonia

Topical chlorhexidine and ventilator-associated pneumonia

The Effectiveness of Current Sterility Techniques in Natural Orifice Transluminal Endoscopic Surgery (NOTES)

Background: NOTES represents a potentially less invasive alternative to conventional laparoscopy. However, breach of the gut wall raises the specter of intra-peritoneal infection. Various anti-microbial techniques have been employed in animal survival studies—including sterile saline rinse, intravenous and topical antibiotics, and Betadine—despite a paucity of data regarding their general effectiveness. Aim: To assess the effectiveness of existing sterilization techniques for NOTES by quantifying and speciating colony-forming units (CFU's) before and after treatment in ex vivo porcine organs. Method: Stomachs and distal colons were harvested en bloc from six fasted adult female white pigs following euthanasia. Four of these animals received 1g of Cefazolin intravenously prior to sacrifice. After the organs were filleted open in sterile fashion, they were further sub-divided into 2.0 cm × 2.0 cm full-thickness square samples. Each tissue sample was then assigned to one of five treatment arms: (1) sterile 0.9% saline lavage, (2) Betadine lavage, (3) lavage with a Cefazolin/Metronidazole suspension, (4) 4% Chlorhexidine lavage, or (5) no treatment. Following 10 minutes of contact time with the treatment solution, the mucosal surface of each tissue sample was swabbed with a sterile cotton applicator and inoculated in 5 ml of normal saline for 1 hour, followed by serial dilutions. 100 mL aliquots of each dilution were plated onto Sheep's blood agar plates and incubated in aerobic conditions at 24 degrees Celsius. Colony-forming units (CFU's) were quantified after seven days, and representative samples were sent to a commercial veterinary laboratory for speciation. Results: Initial bacterial density was estimated to be 1.0 × 106 CFU's/cm2 for stomach and 1.2 × 106 CFU's/cm2 for colon. The predominant organisms were Escherichia coli in stomach and both Escherichia coli and Enterococcus sp in colon. Sterile normal saline lavage caused a 1-log reduction to 2.3 × 105 CFU's/cm2. Antibiotic lavage caused a 2-log reduction to 6 × 104 CFU's/cm2. Betadine lavage a 5-log reduction to 4.1 × 101 CFU's/cm2. Finally, Chlorhexidine lavage also caused a 5-log reduction to 6.0 × 101 CFU's/cm2. The use of intravenous antibiotics alone diminished bacterial load to 10 CFU's/cm2. The combined use of intravenous antibiotics and Betadine or Chlorhexidine decreased counts to zero. Data was analyzed using ANOVA 2-way analysis method and found to be statistically significant (P = 0.001). Conclusions: The use of intravenous antibiotics in addition to topical Betadine or Chlorhexidine effectively eradicated bacteria in both gastric and colonic mucosa in this porcine model.

Topical chlorhexidine for prevention of ventilator-associated pneumonia: A meta-analysis*

To assess the efficacy of topical chlorhexidine for prevention of ventilator-associated pneumonia (VAP) in a meta-analysis. Computerized PubMed and MEDLINE search supplemented by manual searches for relevant articles. Randomized controlled trials evaluating efficacy of topical chlorhexidine applied to the oropharynx vs. placebo or standard care for prevention of VAP. Data were extracted on patient population, inclusion and exclusion criteria, diagnostic criteria for VAP, form and concentration of topical chlorhexidine used, incidence of VAP, and overall mortality. Data on incidence of VAP and mortality were abstracted as dichotomous variables. Pooled estimates of the relative risk and 95% confidence intervals were obtained using the DerSimonian and Laird random effects model and the Mantel-Haenszel fixed effects model. Heterogeneity was assessed using the Cochran Q statistic and I. Subgroup analyses were used to explore heterogeneity. Seven randomized controlled trials met the inclusion criteria. Topical chlorhexidine resulted in a reduced incidence of VAP (relative risk, 0.74; 95% confidence interval, 0.56-0.96; p=.02) using a fixed effects model. Using the more conservative random effects model, the point estimate was similar (relative risk, 0.70; 95% confidence interval, 0.47-1.04; p=.07), but the results failed to achieve statistical significance. The I test showed moderate heterogeneity. Subgroup analysis showed that the benefit of chlorhexidine was most marked in cardiac surgery patients (relative risk, 0.41; 95% confidence interval, 0.17-0.98; p=.04). There was no mortality benefit with chlorhexidine although the sample size was small. Our analysis showed that topical chlorhexidine is beneficial in preventing VAP; the benefit is most marked in cardiac surgery patients. A large randomized trial is needed to determine the impact of topical chlorhexidine on mortality.

Topical minocycline microspheres versus topical chlorhexidine gel as an adjunct to mechanical debridement of incipient peri-implant infections: a randomized clinical trial

Topical minocycline microspheres versus topical chlorhexidine gel as an adjunct to mechanical debridement of incipient peri-implant infections: a randomized clinical trial

Impact of Umbilical Cord Cleansing With 4.0% Chlorhexidine on Time to Cord Separation Among Newborns in Southern Nepal: A Cluster-Randomized, Community-Based Trial

Within a community-based, cluster-randomized study of the effects of 4.0% chlorhexidine on omphalitis and mortality risk, we aimed to describe the distribution of times to separation and the impact of topical chlorhexidine treatment on cord-separation times. Between November 2002 and March 2005, 15123 infants were assigned randomly within communities in southern Nepal to receive 1 of the following 3 cord-care regimens: cleansing with 4.0% chlorhexidine, cleansing with soap and water, or dry cord care. In intervention clusters, field workers cleansed the cord in the home on days 1, 2, 3, 4, 6, 8, and 10 after birth. Newborns were monitored throughout the newborn period for signs of omphalitis, and the time to cord separation was noted. Separation times were compared across treatment groups. Cord infection risk and a range of infant and household characteristics were assessed for their relationships to separation time. The mean separation time was shorter in dry cord care (4.24 days) and soap/water (4.25 days) clusters than in chlorhexidine clusters (5.32 days; mean difference: 1.08 days). Cords of infants who received chlorhexidine were 3.6 times more likely to separate after 7 days. Separation time was not associated with omphalitis. Home-delivered topical antiseptics, facility-based birth, and birth attendant hand-washing were associated with greater likelihoods of cord separation after 7 days of age. In this setting, the umbilical cord separated more rapidly than observed in hospital-based studies, and the impact of chlorhexidine cleansing on separation times was negligible. Increased cord-separation time attributable to topical chlorhexidine treatment should not be considered a factor in decision-making in settings where the baseline risk of omphalitis is high and chlorhexidine might reduce infection and mortality risks significantly.

Risk Factors for Umbilical Cord Infection among Newborns of Southern Nepal

Although umbilical cord infection contributes to neonatal mortality and morbidity and risk can be reduced with topical chlorhexidine, behavioral or other factors associated with cord infection in low-resource settings have not been examined. Data on potential risk factors for omphalitis were collected during a community-based, umbilical cord care trial in Nepal during 2002-2005. Newborns were evaluated in the home for signs of umbilical cord infection (pus, redness, and swelling). Omphalitis was defined as either pus discharge with erythema of the abdominal skin or severe redness (>2 cm extension from the cord stump) with or without pus. Multivariable regression modeling was used to examine associations between omphalitis and maternal, newborn, and household variables. Omphalitis was identified in 954 of 17,198 newborns (5.5%). Infection risk was 29% and 62% higher in infants receiving topical cord applications of mustard oil and other potentially unclean substances, respectively. Skin-to-skin contact (relative risk (RR) = 0.64, 95% confidence interval (CI): 0.43, 0.95) and hand washing by birth attendants (RR = 0.73, 95% CI: 0.64, 0.84) and caretakers (RR = 0.76, 95% CI: 0.60, 0.95) were associated with fewer infections. In this community, unhygienic newborn-care practices lead to continued high risk for omphalitis. In addition to topical antiseptics, simple, low-cost interventions such as hand washing, skin-to-skin contact, and avoiding unclean cord applications should be promoted by community-based health workers.

OC8 The short‐term efficacy of osseointegrated implants in patients with non‐malignant oral mucosal disease: a case series

Purpose The spectrum of patients who may wish or warrant osseointegrated implants is increasing, despite few reports of the impact of non‐malignant oral mucosal disease upon implant placement. This report details the implant placement outcomes in three patients with pre‐existing oral mucosal disease.Case reports A: Four implants were placed in the lower anterior region of a 78‐year‐old female with longstanding mucous membrane pemphigoid (MMP) in 2004. The MMP had resulted in extensive cicatrisation of the upper and lower buccal and labial vestibules. One implant failed to osseointegrate, but was successfully replaced. There have been no other postplacement adverse events, despite the MMP remaining mildly active. B: A 36‐years‐old male with orofacial granulomatosis characterised by recurrent lip swelling and gingival enlargement, had a single implant placed in the upper canine region in 2001. Although still in situ significant peri‐implant alveolar bone loss has occurred and has been stabilised by repeated debridement, local administration of topical minocycline and several courses of systemic metronidazole. C: A 53‐years‐old female with oral manifestations of diffuse systemic sclerosis and fibrosing alveolitis had four lower anterior mandibular implants placed in 1995 to support an 8 unit bridge. One episode of peri‐implant inflammation was controlled with local debridement and topical chlorhexidine mouthrinse. The implants remain satisfactory 11 years postinsertion.Conclusion The short‐term failure of osseointegrated implant integration appears uncommon in patients with non‐malignant oral mucosal disease. There remains a need to establish appropriate case selection criteria and monitor outcomes.

Acanthamoeba Keratitis After LASIK

To report a case of Acanthamoeba infection following LASIK. A 20-year-old woman developed pain, redness, decreased vision, and corneal infiltrate in the right eye 15 days after bilateral LASIK. She did not use contact lenses postoperatively. Patient examination 3 months after surgery revealed a large, central, full-thickness corneal infiltrate with multiple satellite lesions in the right eye. Corneal scrapings were taken and the flap excised, and submitted for histopathologic examination. Microscopic examination of smears revealed Acanthamoeba cysts and non-nutrient agar showed a significant growth of Acanthamoeba. Histopathology examination of the excised flap demonstrated numerous Acanthamoeba cysts in tissue sections. The infiltrate was treated with a combination of topical polyhexamethylene biguanide, chlorhexidine, atropine sulfate, and oral itraconazole and resolved within 2 months. Laser in situ keratomileusis can be complicated by Acanthamoeba infection. Microbiologic evaluation is essential for accurate early diagnosis and treatment.

Topical minocycline microspheres versus topical chlorhexidine gel as an adjunct to mechanical debridement of incipient peri‐implant infections: a randomized clinical trial

This randomized clinical trial presents a 12-month follow-up of the clinical and microbiological results after application of minocycline microspheres as an adjunct to mechanical treatment of incipient peri-implant infections compared with an adjunctive treatment using 1% chlorhexidine gel application. Thirty-two subjects with probing depth > or =4 mm, combined with bleeding and/or exudate on probing and presence of putative pathogenic bacteria were given oral hygiene instructions and mechanical treatment of infected areas adjacent to implants. The subjects were then randomly assigned adjunctive subgingival antimicrobial treatment using either chlorhexidine gel or minocycline microspheres. Sixteen patients in the minocycline group and 14 in the chlorhexidine group completed the study. Follow-up examinations were carried out after 10 days, 1, 2, 3, 6, 9 and 12 months. The adjunctive use of minocycline microspheres resulted in improvements of probing depths and bleeding scores, whereas the adjunctive use of chlorhexidine only resulted in limited reduction of bleeding scores. For the deepest sites of the treated implants in the minocycline group, the mean probing depth was reduced from 5.0 to 4.4 mm at 12 months. This study could not show any significant difference in the levels of bacterial species or groups at any time point between the two antimicrobial agents tested. The present findings encourage further studies on adjunctive use of minocycline microspheres in the treatment of peri-implant lesions. The use of a local antibiotic as an adjunct to mechanical treatment of incipient peri-implantitis lesions demonstrated improvements in probing depths that were sustained over 12 months.

Effectiveness of topical chlorhexidine powder as an alternative to hexachlorophane for the control of Staphylococcus aureus in neonates

We routinely phage-type Staphylococcus aureus isolates from high-risk inpatients each week. This surveillance approach previously identified a five-year outbreak of a methicillin-susceptible S. aureus strain (MSSA, PT 53,85), which affected 202 babies on a regional neonatal unit. We previously reported this outbreak and the multiple staged infection control measures that were required to end it. These included strict emphasis on hand hygiene, environmental and staff surveillance sampling, application of topical triclosan solution and hexachlorophane powder, aseptic handling of a skin protectant material, and use of topical mupirocin for staff nasal carriers of the endemic MSSA strain and for babies colonized or infected with S. aureus. In summer 2000 topical hexachlorophane powder became unavailable and we therefore substituted topical 1% chlorhexidine powder as part of routine umbilical decontamination. We have continued prospective S. aureus surveillance for the past five years to monitor the effect of this practice change. We observed a continued decline in the numbers of monthly MSSA isolates from neonatal unit babies. Since the substitution of chlorhexidine for hexachlorophane, the median monthly number of MRSA isolates has been 0.5 (range 0–4). Only sporadic S. aureus PT 53,85 isolates were recovered. Control of S. aureus in our regional neonatal unit, in particular an endemic MSSA strain, was maintained when topical umbilical hexachlorophane powder was substituted with 1% chlorhexidine powder.

No difference between topical chlorhexidine and fluoride varnishes in preventing caries?

Design A 3-year randomised controlled trial in 180 13 to 14-year-old subjects.Intervention Either 0.1% fluoride or 1% chlorhexidine/thymol varnish professionally applied after prophylaxis every 3 months.Outcome measure Caries increment was identified using bitewing radiographs. The assessor was blind to treatment allocation.Results There were no significant differences between the two groups, with about three new approximal surfaces per child decayed or filled in each group, mostly restricted to the enamel surface (see Table 1).Conclusions There was no difference in caries experience with the use of fluoride varnish compared with the use of chlorhexidine varnish.

Effects of topical chlorhexidine applied to the rabbit nasal mucosa

Objective: To search the effects of administration of various concentrations of a wide-spectrum antimicrobial agent, chlorhexidine, to the nasal mucosa. Material and methods: About 0.20, 0.12, 0.06 and 0.03% concentrations of chlorhexidine gluconate were applied to the rabbit nasal mucosa as one puff twice a day throughout 5 days. Another group, treated with serum saline to the nose, behaved as the control group. On the fifth day following drug administration, specimens were taken from nasal mucosa of the rabbits and examined under light microscope. Results: As a result of comparison between drug treated group and control group, with increasing drug concentrations progressively increased neutrophil infiltration in mucosa, ciliary loss in cells, and occasional metaplasia were observed. Conclusion: There is a linear, positive and strong association between concentrations of chlorhexidine and its irritative effects on rabbit nasal mucosa. While 0.20 and 0.12% concentrations of chlorhexidine cause excess irritation on the nasal cavity, 0.06 and 0.03% concentrations of chlorhexidine gluconate causes lower irritation and effects on the animals which have experimentally induced rhinosinusitis must be evaluated.