Vaginal Isolates Of Candida Albicans Research Articles

Resistance to Fluconazole of Candida albicans in Vaginal Isolates: a 10-Year Study in a Clinical Referral Center.

Review of vaginal isolates of Candida albicans that caused clinical failure in a 10-year collection of vaginal C. albicans specimens obtained in a university vaginitis referral clinic indicated an increase in fluconazole resistance. Factors contributing to azole resistance are discussed, including treatment choice associated with fluconazole-resistant C. albicans vaginal infection.

Sweet Relief: Determining the Antimicrobial Activity of Medical Grade Honey Against Vaginal Isolates of Candida albicans.

Recurrent vulvovaginal candidiasis (RVVC) is predicted to increase to almost 158 million cases annually by 2030. Extensive self-diagnosis and easily accessible over-the-counter (OTC) fungistatic drugs contribute to antifungal-resistance, illustrating the need for novel therapies. Honey possesses multiple antimicrobial mechanisms, and there is no antimicrobial resistance towards honey reported. We evaluated the susceptibility of five clinical isolates of Candida albicans and a control strain to regular honey and a medical grade honey (MGH) gel formulation (L-Mesitran, containing 40% honey and vitamins C and E) using an adapted version of the EUCAST protocol at pH 5.2, 4.6, and 4.0. 40% regular honey did not kill or inhibit C. albicans. In contrast, the minimal inhibitory concentration (MIC) of L-Mesitran was 25%–50%, while fungicidal effects occurred at a 50% concentration (MBC) of the MGH formulation, except for one strain which was not killed at pH 4.0. Overall, pH had little effect on antimicrobial activity. MGH formulation L-Mesitran has antimicrobial activity against C. albicans over a relevant pH range. The vitamin supplements or other components of L-Mesitran may enhance the antifungal activity of the honey. This study supports performing clinical trials for conditions, such as RVVC, to find an alternative to available OTC fungistatic drugs.

Antifungal effects of ethanolic and aqueous extracts of Vitex agnus-castus against vaginal isolates of Candida albicans

Background and Purpose: Vulvovaginal candidiasis is one of the most common infections in female genital organs, which is caused by Candida species. Candida albicans is the causative agent of more than 80% of infections, and the role of non-Candida strains in the disease etiology is less prominent. The expansion of Azoles resistance among C. albicans strains is considered an important medical problem. According to previous studies, Vitex agnus-castus (vitex) has some antimicrobial effects. We aimed to evaluate the anti-fungal effects of aqueous and alcoholic extracts of vitex against clinical vaginal isolates of C. albicans in comparison with fluconazole.
 Materials and Methods: Gas chromatography-mass spectrometry analysis was performed on vitex to identify its possible bioactive components. Forty C. albicans clinical isolates were identified by using germ tube, chlamydospore production, culture on CHROMagar, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Finally, after the extraction of vitex, drug susceptibility test was carried out according to the clinical laboratory standards institute (CLSI) M27-S4 document guidelines.
 Results: The major chemical components of vitex leaf as determined by gas chromatography included α-Pinene, isoterpinolene, caryophyllene, and azulene. The minimum inhibitory concentrations (MICs) of aqueous and alcoholic extracts of vitex, as well as fluconazole were within the ranges of 15.62–62.5, 7.81–15.62, and 0.25–8 μg/mL, respectively.
 Conclusion: Our findings showed that the alcoholic and aqueous extracts of vitex had antifungal activity against clinical isolates of C. albicans. Moreover, the alcoholic extract of vitex and fluconazole were more effective against clinical vaginal isolates of C. albicans compared to the aqueous extract of vitex.

Antifungal effects of ethanolic and aqueous extracts of Vitexagnus-castus against vaginal isolates of Candida albicans.

Background and Purpose:Vulvovaginal candidiasis is one of the most common infections in female genital organs, which is caused by Candida species. Candida albicans is the causative agent of more than 80% of infections, and the role of non-Candida strains in the disease etiology is less prominent. The expansion of Azoles resistance among C. albicans strains is considered an important medical problem. According to previous studies, Vitex agnus-castus (vitex) has some antimicrobial effects. We aimed to evaluate the anti-fungal effects of aqueous and alcoholic extracts of vitex against clinical vaginal isolates of C. albicans in comparison with fluconazole.Materials and Methods:Gas chromatography-mass spectrometry analysis was performed on vitex to identify its possible bioactive components. Forty C. albicans clinical isolates were identified by using germ tube, chlamydospore production, culture on CHROMagar, and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Finally, after the extraction of vitex, drug susceptibility test was carried out according to the clinical laboratory standards institute (CLSI) M27-S4 document guidelines.Results:The major chemical components of vitex leaf as determined by gas chromatography included α-Pinene, isoterpinolene, caryophyllene, and azulene. The minimum inhibitory concentrations (MICs) of aqueous and alcoholic extracts of vitex, as well as fluconazole were within the ranges of 15.62–62.5, 7.81–15.62, and 0.25–8 μg/mL, respectively.Conclusion:Our findings showed that the alcoholic and aqueous extracts of vitex had antifungal activity against clinical isolates of C. albicans. Moreover, the alcoholic extract of vitex and fluconazole were more effective against clinical vaginal isolates of C. albicans compared to the aqueous extract of vitex.

Genotypic analysis of secreted aspartyl proteinases in vaginal Candida albicans isolates

ABSTRACT Introduction: Candida albicans is the most common etiologic agent of fungal vaginitis. These yeasts produce secreted aspartyl proteinases encoded by a family of 10 genes (SAP1-10). Objective: The purpose of this study was to analyze the presence of genes SAP1-7 in vulvovaginal C. albicans. Materials and method: The study included 26 C. albicans vaginal isolates. Detection of aspartyl proteases genes (SAP1-7) was performed by polymerase chain reaction (PCR). Results: The most frequent gene in C. albicans isolated from colonization was SAP6 (93.33%), and from infection, SAP7 (100%). We observed a statistical difference (p = 0.049) in SAP1 gene frequency between isolates from vulvovaginal colonization and infection. Conclusion: High frequency of SAP genes was observed in vulvovaginal C. albicans. The results suggest SAP1 participation in vulvovaginal candidiasis infection.

Cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies.

The present study aimed to characterize cell damage caused by vaginal Candida albicans isolates from women with different symptomatologies. It was evaluated 12 clinical isolates of C. albicans from vaginal samples: 4 from asymptomatic women (AS), 4 from women with a single episode of vulvovaginal candidiasis (VVC) and 4 from women with recurrent vulvovaginal candidiasis (RVVC). We evaluated the ability of C. albicans to adhere to human cervical cancer cells (SiHa), the yeast-SiHa cell interactions and cell damage. All of the clinical isolates presented a high adhesion capacity on SiHa cells. However, clinical isolates from symptomatic women (VVC and RVVC) had higher filamentation after contact (24 h) with SiHa cells and a greater capacity to cause cell damage (>80 %). Clinical isolates from symptomatic women had greater potential to invade SiHa cells, suggesting that they are more pathogenic than AS isolates.

Extracellular Esterase Secretion by Vaginal Isolates of Candida Albicans

Extracellular Esterase Secretion by Vaginal Isolates of Candida Albicans

Clinical characteristics of vulvovaginal candidiasis and antifungal susceptibilities of Candida species isolates among patients in southern China from 2003 to 2006

To determine the clinical characteristics of vulvovaginal candidiasis (VVC), the Candida species involved and the antifungal susceptibility of Candida species isolated from patients with VVC. Candida organisms were cultured from samples obtained from patients who presented with VVC to the Gynecology Department, Peking University Shenzhen Hospital. Antifungal susceptibility testing was performed using a commercial agar diffusion test. Of the 1,070 cases of VVC reported in this study, 36.5% were uncomplicated VVC, and 63.5% were complicated VVC. Twenty-four patients were identified as having two species of Candida. Candid albicans alone was isolated from 89.5% of cases (n = 958). Candida glabrata was isolated from 85 cases (7.9%), Candida tropicalis from 10 (0.9%), Saccharomyces cerevisiae from eight (0.7%), Candida parapsilosis from six (0.6%), Candida famata from two (0.2%), and Candida krusei from one case (0.1%). All isolates of Candida albicans were susceptible to nystatin. The resistant rate of Candida albicans to azole agents was 0-4.9%. Candida albicans was the predominant Candida species isolated from this series of patients with VVC. Resistance of vaginal Candida albicans isolates to antifungal agents was infrequent.

Therapeutic efficacy of posaconazole against isolates ofCandida albicanswith different susceptibilities to fluconazole in a vaginal model

A battery of 34 vaginal isolates of Candida albicans was tested against posaconazole (POS) and fluconazole (FLU) to determine their in vitro susceptibilities and to obtain FLU-susceptible and FLU-resistant strains for the murine in vivo studies. FLU-resistant strains were chosen on the basis of their 48-h MICs. The 48-h geometric mean MICs for all isolates tested were 0.016 and 0.656 microg/ml for POS and FLU, respectively. The treatment regimens for the vaginal murine infection model were POS or FLU at 10 or 20 mg/kg of body weight/day and 20 mg/kg twice a day. All regimens with POS were effective in reducing fungal burden of both the fluconazole-susceptible and resistant isolates of C. albicans. All FLU regimens were effective against infection induced by the fluconazole-susceptible strain. While FLU at 10 mg/kg was ineffective against fungal burden of the resistant strain, treatment with FLU at 20 mg/kg once or twice a day was effective against this strain. Both POS and FLU at 20 mg/kg twice a day were able to clear C. albicans from vaginas of mice infected with the fluconazole-susceptible strain. POS displayed a more effective in vivo activity than FLU in the treatment of murine C. albicans vaginitis produced by isolates with different susceptibilities to FLU.

Characterization of Weissella kimchii PL9023 as a potential probiotic for women

From more than 100 lactic acid bacteria, Weissella kimchii PL9023 was selected as producing the most hydrogen peroxide and was characterized as a probiotic for women. W. kimchii PL9023 inhibited the growth and adherence of vaginal isolates of Candida albicans, Escherichia coli, Staphylococcus aureus and Streptococcus agalactiae. The surface components involved in adherence of W. kimchii PL9023 to vaginal epithelial cells appeared to be glycoproteins, as determined by susceptibility to proteinase K, heat, or periodate. W. kimchii PL9023 did not produce harmful metabolites or enzymes. The results of this study suggest that W. kimchii PL9023 is a potential probiotic for vaginal health.

Assessment of genetic relatedness of vaginal isolates of Candida albicans from different geographical origins

PCR fingerprinting with single non-specific primers was used to type vaginal isolates of C. albicans from Portugal, Angola, Madagascar, and two regions of Germany (Berlin and Munich). In addition to analysing isolates that exhibited the normal biotype of C. albicans, the study included atypical strains that failed to assimilate glucosamine and N-acetylglucosamine, which were isolated from women in Angola and Madagascar. A total of 212 strains of C. albicans were studied, representing 87 different multi-locus genotypes. The genotypes of strains from each geographical population were highly similar but not identical. There was one exception: a strain from Portugal grouped with the typical strains from Angola. The typical and especially the atypical populations from Africa displayed less genotype variation than the populations from Europe. The Portuguese samples exhibited the greatest genotypic heterogeneity. Distance analysis (UPGMA) revealed a statistically weak correlation between genotype and geographical origin of the C. albicans isolates.

DNA FINGERPRINTING AND KARYOTYPE OF CANDIDA ALBICANS ISOLATED FROM VAGINAL INFECTIONS

The vaginopathic potential and the intravaginal morphology of different Candida albicans strains isolated from 25 symptomatic cases suffering from vaginitis and from 25 asymptomatic cases were studied. During infection of symptomatic patients, the Candida albicans cells did not maintain their yeast morphology but gave rise to hyphal filaments and germ tube formation as well as protease production. Vaginal Candida albicans isolates taken from the asypmtomatic patients were found to have inability of protease production and germ tube formation. Candida albicans cells forming germ tube demonstrated the highest percentage of adherence to epithelial cells. DNA figerprinting and electrophoretic karyotype anal ysis of Candida albicans strains of different morphology and pathology proved to have different DNA bands pattern of fingerprint. The results suggest that protease production, germ tube formation and adherence to epithelial cells play an important role in virulence of Candida albicans.

High aspartyl proteinase production and vaginitis in human immunodeficiency virus-infected women.

Vaginal isolates of Candida albicans from human immunodeficiency virus-positive (HIV+) and HIV- women with or without candidal vaginitis were examined for secretory aspartyl proteinase (Sap) production in vitro and in vivo and for the possible correlation of Sap production with pathology and antimycotic susceptibility in vitro. HIV+ women with candidal vaginitis were infected by strains of C. albicans showing significantly higher levels of Sap, a virulence enzyme, than strains isolated from HIV+, C. albicans carrier subjects and HIV- subjects with vaginitis. The greater production of Sap in vitro was paralleled by greater amounts of Sap in the vaginal fluids of infected subjects. In an estrogen-dependent, rat vaginitis model, a strain of C. albicans producing a high level of Sap that was isolated from an HIV+ woman with vaginitis was more pathogenic than a strain of C. albicans that was isolated primarily from an HIV-, Candida carrier. In the same model, pepstatin A, a strong Sap inhibitor, exerted a strong curative effect on experimental vaginitis. No correlation was found between Sap production and antimycotic susceptibility, as most of the isolates were fully susceptible to fluconazole, itraconazole, and other antimycotics, regardless of their source (subjects infected with strains producing high or low levels of Sap, subjects with vaginitis or carrier subjects, or subjects with or without HIV). Thus, high Sap production is associated with virulence of C. albicans but not with fungal resistance to fluconazole in HIV-infected subjects, and Sap is a potentially new therapeutic target in candidal vaginitis.

Phenotypic and genotypic characterization of unusual vaginal isolates of Candida albicans from Africa.

As expected by its global prevalence, the most frequently isolated species of yeast from vaginal swabs obtained from patients in Africa was Candida albicans, which accounted for 53 of 85 (62.4%) of the isolates from women in Madagascar and 35 of 54 (64.8%) of the culture-positive women in Angola. However, 40% of the Madagascan and 23% of the isolates from Angola, as well as two isolates obtained from one German patient, were not able to utilize the amino sugars glucosamine and N-acetylglucosamine as the sole carbon source. These isolates were able to form germ tubes but did not form chlamydospores. The correct identification as C. albicans was made possible only by using a PCR-based method of DNA fingerprinting. Only minor phenotypic and genotypic variation was observed among these strains. Whether they represent a distinct clone that is found mainly in Africa is not clear. The relevance of the amino sugar catabolic pathway in C. albicans is discussed in view of these results.

Comparativein vitroactivity of antimycotic agents against pathogenic vaginal yeast isolates

Although numerous antimycotic agents are available for the treatment of yeast vaginitis there is little comparative data on the in vitro activity of these drugs. In the present two-part study, in vitro macro-broth dilution sensitivity tests were performed on a total of 377 clinical vaginal yeast isolates of nine different species. Antimycotics surveyed included amphotericin B, 5-fluorocytosine and eight azole derivatives. Results show that all vaginal Candida albicans isolates were uniformly sensitive at low concentration to all 10 antimycotics tested. However, non-albicans species, especially Candida glabrata and Saccharomyces cerevisiae, manifested several-fold increases in minimal inhibitory concentrations to all azoles tested except butoconazole. In particular, the in vitro potency of fluconazole and terconazole against species other than C. albicans was relatively poor, whereas the drugs demonstrating the best activity were itraconazole, butoconazole and saperconazole. Susceptibility testing of vaginal C. albicans isolates is not routinely indicated, even in patients with recurrent vaginitis and should be reserved for selected organisms, especially non-albicans species, in patients with clinical failure only.

Biological Attributes of Colony-type Variants of Candida albicans

Twenty 'commensal' oral or 'pathogenic' vaginal isolates of Candida albicans were examined for colony morphology on malt/yeast-extract and serum-based agar media. Diverse and variable colony morphology was seen on serum agar. In 17 strains, selective subculture of morphologically atypical colonies produced progeny which had reverted to the morphology of the majority of parental colonies. However, in one strain, a highly stable colony variant was isolated which did not revert on subculture. In two further strains, variants were isolated which could be maintained with at least 99% homogeneous colony type by selective colony subculture, but reversion to the parental type or switching to other morphologies occurred at rates of 10(-2) to 10(-4): a rapid switching phenomenon. The relative proportions of mycelial or yeast forms were the main determinants of colony morphology. The variants were biotyped using a selection of biochemical tests. The stable variant differed from its parent in several characters, including rate of production of a proteinase enzyme. The pathogenicity of variants was compared in mice, and both stable and switching variants differed in virulence from their parental strains. Colony-type variation on suitable media is thus a powerful tool in the isolation of mutants or variants of C. albicans which differ from 'isogenic' parents in significant biological properties. Such variants may aid identification and characterization at the molecular level of determinants of, for example, pathogenicity and morphogenesis.

Decrease in adherence of bacteria and yeasts to human mucosal epithelial cells by noxythiolin in vitro.

Adherence of buccal and vaginal isolates of Candida albicans to buccal epithelial cells and the adherence of urine isolates of Escherichia coli and Staphylococcus saprophyticus to uroepithelial cells was quantified by light microscopy. The antimicrobial agent noxythiolin reduced the adherence of these micro-organisms in both exponential and stationary growth phases. Adherence of both the blastospore and pseudohyphal forms of C. albicans was reduced. Treatment of epithelial cells and/or micro-organisms with noxythiolin resulted in decreased adherence. No anti-adherence effect was observed with formaldehyde and N-methylthiourea, the degradative products of noxythiolin.