Mrudula Patel

Antifungal activity of the plant Dodonaea viscosa var. angustifolia on Candida albicans from HIV-infected patients

THE AIM OF THIS STUDY was to determine the minimum inhibitory concentration (MIC) and the time taken by Dodonaea viscosa var. angustifolia (PLE) a South African medicinal plant, chlorhexidine gluconate (CHX) and triclosan (TRN) to kill Candida albicans. 41 strains of Candida albicans were investigated, 20 from HIV-positive patients, 20 from HIV-negative subjects and Candida albicans ATCC 90028. The MICs of an acetone extract of PLE, CHX and TRN were measured using a microtitre double dilution technique, and the time taken to kill 99.5% of the strains was determined. The MICs of PLE, CHX and TRN were 6.25-25, 0.008-0.16 and 0.0022-0.009 mg/ml, respectively. PLE killed all the test strains within 30s and CHX 40% of the isolates from HIV-positive patients and 20% of strains from HIV-negative subjects in 1 min. During the same time TRN killed 55% and 35% of isolates from HIV-positive and HIV-negative patients. Dodonaea viscosa var. angustifolia has antifungal properties and is more effective than commercially available mouthrinses.

Antifungal Effect of Mouth Rinses on Oral Candida Counts and Salivary Flow in Treatment-Naïve HIV-Infected Patients

Oral candidiasis is a major problem in developing countries where antiretroviral therapy is available to a small percentage of the infected population. HIV patients are prone to xerostomia and predisposed to Candida infection. Preventing oral candidiasis is better than the frequent use of antifungals that may lead to the development of drug resistance. This study investigated the ability of commercial mouth rinses and sodium bicarbonate to reduce salivary Candida and to improve the saliva flow of HIV-positive patients. One hundred fifty HIV patients without oral candidiasis were examined for oral lesions initially and after 2, 4, and 12 weeks. Unstimulated saliva was collected; the volume was measured and cultured for yeasts. Subjects were provided with mouth rinses containing either benzydamine hydrochloride, benzydamine hydrochloride with chlorhexidine gluconate, triclosan with sodium fluoride, 5% sodium bicarbonate, or placebo and asked to rinse twice daily for 12 weeks. The effect of the mouth rinses and placebo on Candida counts and saliva flow was analyzed using analysis of variance (ANOVA). A total of 108 patients completed the trial, 35 missed appointments, 4 died, 2 developed oral candidiasis, and 1 herpetic lesion. Triclosan/fluoride decreased the Candida count more than the placebo (p = 0.005) while chlorhexidine/benzydamine hydrochloride (p = 0.001) and triclosan/fluoride mouthrinses (p = 0.002) increased the salivary flow during the initial 4 weeks. The most effective mouth rinse triclosan/fluoride decreased oral Candida counts and increased saliva flow. Studies are needed to determine the efficacy of these mouth rinses for the long-term prevention of clinical oral candidiasis in adult HIV-positive patients.

Inhibitory activity of Dodonaea viscosa var. angustifolia extract against Streptococcus mutans and its biofilm

ETHNOPHARMACOLOGICAL RELEVANCE The leaves of Dodonaea viscosa var. angustifolia (DVA) are traditionally used for the treatment of fever, colds, oral thrush, toothaches and related problems. Streptococcus mutans is implicated in many oral infections. This study investigated the inhibitory activity of DVA extract against Streptococcus mutans and its biofilm. MATERIALS AND METHODS Crude extract of the leaves was prepared using methanol. The time-kill curve for Streptococcus mutans at different concentrations of methanol extract after 6 and 24 h was determined. Biofilms of Streptococcus mutans were grown in the presence of subinhibitory concentration of extract (0.78 mg/ml) for 30 h and the bacterial counts were obtained after 6, 24 and 30 h. The chemical profile of the crude extract was obtained using gas chromatography-mass spectrometry (GC-MS). RESULTS The reduction of Streptococcus mutans was concentration and exposure time dependent. The crude extract killed 48% of S. mutans at a lowest concentration of 0.1 mg/ml and 100% at 25 mg/ml after 6h. Biofilm formation was reduced by 95, 97 and 99% after 6, 24 and 30 h of exposure to the subinhibitory concentration of crude extract respectively. GC-MS analyses revealed the presence of polyphenols such as catechin or chromene groups, chalcones with trimethoxyphenyl group and tannin with 4-O-β-D-xylopyranoside. At high concentration the crude extract was bactericidal to Streptococcus mutans but subinhibitory concentration significantly reduced the planktonic cells and biofilm formation. CONCLUSIONS These results suggest that this plant has the potential to be used to control S. mutans and its biofilm which are responsible for oral infections.

The effect of Dodonaea viscosa var. angustifolia on Candida albicans proteinase and phospholipase production and adherence to oral epithelial cells.

AIM OF THE STUDY This study investigated effect of a crude extract of Dodonaea viscosa on the proteinase and phospholipase production and adherence to epithelial cells by Candida albicans isolated from HIV positive and HIV negative patients. MATERIALS AND METHODS Twenty Candida albicans strains isolated from HIV positive and 20 from HIV negative patients were investigated. The isolates were exposed to subinhibitory concentration of crude plant extract and adherence, proteinase and phospholipase production were assessed. The results were analysed using Students t-test and a two-way ANOVA. RESULTS Dodonaea viscosa var. angustifolia inhibited the adherence of Candida albicans to oral epithelial cells (p=<0.01) but no significant effect of the plant extract on proteinase and phospholipase production was observed. Results from Candida albicans strains isolated from HIV positive and HIV negative patients were similar. CONCLUSIONS Dodonaea viscosa var. angustifolia inhibited the adherence of Candida albicans to oral epithelial cells, which is the initial step of colonization in the infection process. This plant has a therapeutic potential at subinhibitory concentration.

Oral Candida colonization in HIV-positive women: associated factors and changes following antiretroviral therapy.

There is a paucity of information about the factors associated with oral colonization with Candida species and the changes associated with antiretroviral (ARV) therapy. This study investigated the role of ARV therapy and other factors in a study population. Relevant clinical and laboratory information was obtained and oral rinse specimens were tested for yeast identification. The findings were compared with previous data from the same clinic before ARV therapy was available. Of 197 patients, 117 (59.4 %) were colonized. Candida albicans was the dominant species (71 %) and Candida dubliniensis was the most frequent non-albicans Candida. The colonized group had a higher rate of concurrent tuberculosis (TB) infection (77.4 % compared with 56 % in the non-colonized patients, P = 0.03) and a lower median CD4(+) count (346.5 cells mm(-3)) compared with the non-colonized group (418 cells mm(-3)). Participants not on ARV therapy and those having oral prosthesis were all colonized (P = 0.003 and P = 0.022, respectively). The oral Candida count was negatively correlated with the CD4(+) count in participants on ARV therapy (P = 0.006). Associated factors using logistic regression were dental caries (odds ratio = 1.30; 95 % confidence interval = 1.07-1.60] and diabetes mellitus (odds ratio = 5.52; 95 % confidence interval = 1.68-18.12). The colonization rate was higher (81.3 %) as well as the yeast count before ARV therapy was available, while the prevalence of C. dubliniensis was found to have increased from 6.3 to 11 %. Dental caries, diabetes mellitus, oral prostheses and TB infection were associated with oral colonization. The colonization rate, variety and yeast counts declined with ARV therapy.

Effect of iron and pH on the survival of Vibrio cholerae in water

Many physicochemical factors affect the survival of Vibrio cholerae in the aquatic environment. An attempt was made to study the combined effect of pH and iron on the survival of V. cholerae in water in a laboratory environment. None of the 6 strains of V. cholerae used survived at pH 5.0; survival of all strains increased with increasing pH. The effect of ferric oxide on survival was significant for V. cholerae O1 only, not for non O1 strains. The longest survival of V. cholerae non O1 was 82 d, of El Tor V. cholerae 68 d, and of classical V. cholerae 56 d.

Isolation of Staphylococcus aureus and black-pigmented bacteroides indicate a high risk for the development of Ludwig's angina.

OBJECTIVE The aim of this study was to compare clinical, microbiological, enzymatic, and host immune response variables between subjects hospitalized with facial cellulitis, with Ludwigs angina (LA) and without Ludwigs angina (WOLA). STUDY DESIGN Microbiological and enzymatic tests on pus, and hematological and immunological assessments on blood samples of 15 patients with LA and 42 patients with WOLA were performed. Laboratory findings of both groups were compared using the Student t test. Multiple logistic regression analysis was performed and significant differences identified by univariate analysis. RESULTS Patients with LA demonstrated increased levels of white blood cell counts, urea, and CRP levels, and decreased levels of CIC compared with patients WOLA. However, only CRP and urea were found to be significantly raised in the LA group. A greater population of Staphylococcus aureus and black-pigmented bacteroides were isolated from patients with LA. CONCLUSION Elevated levels of CRP and urea could indicate the severity of infection in patients with LA. This could be because of the highly virulent and fast-spreading organisms, S. aureus and black-pigmented bacteroides, which may be a factor indicative of LA.

Virulence of oral Candida isolated from HIV-positive women with oral candidiasis and asymptomatic carriers

OBJECTIVE This study compared the virulence of oral Candida species isolated from human immunodeficiency virus (HIV)-positive women with and without oral candidiasis. STUDY DESIGN Candida species were isolated from 197 women, and their virulence attributes were measured. RESULTS Of the 197 women, 117 (59.4%) carried Candida. Of these, 15 (12.8%) had symptoms of oral candidiasis. Among highly active antiretroviral therapy (HAART)-naive patients, 33% were diagnosed with oral candidiasis, whereas 5.9% were asymptomatic carriers (P < .01). C. albicans was the predominant species, with higher virulence attributes than non-albicans Candida. Women diagnosed with oral candidiasis had higher levels of Candida (P = .02) than asymptomatic carriers. There was no difference in the CD4 counts and the virulence attributes of Candida from both the groups. CONCLUSIONS This study indicates that oral candidiasis is mainly caused by high counts of C. albicans and suggests the importance of therapies targeting Candida counts in the oral cavity even in patients on HAART to reduce the development of infections.

Dodonaea viscosa var. angustifolia Inhibits Germ Tube and Biofilm Formation by C. albicans

The virulence factors of Candida albicans are germ tube and biofilm formation, adherence to host tissues, and production of hydrolytic enzymes. This study investigated the effect of Dodonaea viscosa var. angustifolia extract on the germ tube and biofilm formation of C. albicans. Serum containing the three subinhibitory concentrations of leaf extract was inoculated with C. albicans, incubated, and viewed under a light microscope. Number of cells with germ tube was recorded and the results were analysed using Scheffe test for pairwise comparison. Biofilms were grown on coverslips in the presence of plant extracts and processed for scanning electron microscopy (SEM). Planktonic cells were grown in the presence of plant extract for 6 h and processed for electron microscopy (TEM). The crude plant extract significantly (P < 0.01) reduced the germ tube formation of C. albicans at 3.125 (85.36%), 1.56 (61.91%), and 0.78 mg/mL (26.27%) showing a concentration dependent effect. SEM results showed concentration dependent reduction in biofilm and hyphae formation. TEM results showed that the plant extract caused damage to the cell wall and cell membrane. DVA extract has ability to reduce virulence of C. albicans by inhibiting germ tube and biofilm formation through damage to the cell wall. Therefore, it has therapeutic potential.

Influence of cancer treatment on the Candida albicans isolated from the oral cavities of cancer patients

PurposeCancer treatment causes mucositis and the manifestation of oral candidiasis. This study investigated the virulence properties and antifungal susceptibilities of Candida albicans isolated from cancer patients undergoing therapy.MethodsC. albicans were isolated from 49 patients on cancer treatment and 21 healthy individuals and their virulence attributes measured. A correlation was determined between the length of treatment and the fungal counts and their virulence factors.ResultsAlthough Candida carriage was similar in all the study groups, high quantities of C. albicans and variety of Candida were found in cancer patients. Germ tubes were produced by all the strains. Significantly high number of yeast isolated from radiotherapy and chemotherapy produced large quantities of phospholipase compared to healthy individuals (p < 0.01). The length of chemotherapy was associated with an increase in the phospholipase production (p = 0.03) by the C. albicans. Proteinase production was seen in a significant number of isolates from the radiotherapy group (p < 0.01). Type of cancer treatment had no effect. Resistance to antifungal agents was low.ConclusionsHigh quantities of phospholipase were produced by C. albicans in cancer patients on therapy which also increased with the length of chemotherapy suggesting enhanced risk of oral and systemic infection. Therefore, during treatment, prophylactic topical antifungal therapy may be considered.