VULVOVAGINAL CANDIDIASIS : By SANDEEP M. WANKHEDE VULVOVAGINAL CANDIDIASIS PowerPoint Presentation: Although VC is mild and treatable, when left untreated , is a possible risk for - Acquisition of HIV/AIDS (UNAIDS, 2003) Pelvic inflammatory disease (PID) Infertility Ectopic pregnancy Pelvic abscess Menstrual disorders Spontaneous abortion and premature birth Therefore, there is a need for prevention, early diagnosis and prompt treatment of this common condition especially among the risk groups. Laboratory support is necessary for a differential diagnosis or to confirm the clinical diagnosis of vaginal candidiasis . Candida virulence factors: Colonisation of the vagina requires yeast adherence to vaginal epithelial cells. C albicans adheres in significantly higher numbers to such cells than do non- albicans . Yeast surface mannoprotein serves as adhesins . Germination of candida cells enhances colonisation and facilitates tissue invasion. Germination of candida is stimulated in vivo by – a) dibutyryl-cAMP ( dbcAMP ) b) glucagon c) serum Virulence is enhanced by a) Proteolytic enzymes – Secreted aspartyl proteinases (SAP1, SAP2, and SAP3) : destroy free and cell bound proteins that impair fungal colonisation and invasion b) Toxins – Mycotoxin including a gliotoxin inhibit phagocytic activity or suppress the local immune system c) Phospholipase d) Hyphal formation e) Phenotypic switching Candida virulence factors Predisposing facotrs & Pathogenesis in VVC: Predisposing facotrs & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Age factor Episodes of VVC occur mostly during childbearing years (18-49 years) and are rare in premenarchal and postmenopausal women . Genetic factors Reports of familial susceptibility to vulvo vaginal candidosis and studies that indicate increased prevalence of vulvovaginal candidosis in African-American women¹ and people with blood group ABO-Lewis² non-secretor phenotype suggest that there could be genetic factors that predispose individuals to colonisation or vaginitis . Also, in-vivo polymorphism studies involving mannose-binding lectin and experimental vaginitis in mice further suggest that some individuals could have a genetic susceptibility to candida colonisation or vaginitis³. 1. Geiger AM, Foxman B. Risk factors for vulvovaginal candidiasis : a case-control study among university students. Epidemiology 1996;7:182–87. 2. Chaim W, Foxman B, Sobel JD. Association of recurrent vaginal candidiasis and secretory ABO and Lewis phenotype. J Infect Dis 1997;176: 828–30. 3. Babula O, Lazdane G, Kroica J, Linhares IM, Ledger WJ, Witkin SS. Frequency of interleukin-4 (IL-4) -589 gene polymorphism and vaginal concentrations of IL-4, nitric oxide, and mannose-binding lectin in women with recurrent vulvovaginal candidiasis . Clin Infect Dis 2005; 40: 1258–62. 4. Calderon L, Williams R, Martinez M, Clemons KV, Stevens DA. Genetic susceptibility to vaginal candidiasis . Med Mycol 2003; 41: 143–47 Predisposing factors & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Pregnancy A higher prevalence of vaginal colonisation and symptomatic vaginitis is more often seen in pregnant women than in those who are not pregnant Recurrences are more common compared with women who are not pregnant. High concentrations of reproductive hormones increase the glycogen content in the vaginal tissue which provide a carbon source for candida organisms. Oestrogen also enhances adherence of yeast to vaginal epithelial cells. A cytosol receptor or binding system in C. albicans for female reproductive hormones results in enhanced mycelial formation. Predisposing factors & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Contraceptives Increased vaginal colonisation with candida is seen after the use of oral contraceptives with high oestrogen content. Most investigators believe that oral contraceptives predispose women to recurrent vulvovaginal candidosis . Increased carriage of yeast is reported in users of - intrauterine contraceptive devices - contraceptive sponges - diaphragms and - condoms with or without spermicides Predisposing factors & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Diabetes mellitus Vaginal colonisation with candida is more frequent in diabetic women than in non- diabetics. Women with type 2 diabetes are more prone to colonisation with C. glabrata . Although uncontrolled diabetes predisposes to symptomatic vaginitis , the prevalence of vulvovaginal candidosis is not increased in individuals with well-controlled diabetes. Occasionally, non-diabetic women with recurrent vulvovaginal candidosis describe an association between binges of sugary confectionery and exacerbation of symptomatic vulvovaginal candidosis . A diet high in refined sugars could contribute to the risk of vulvovaginal candidosis Predisposing factors & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Antibiotics Symptomatic vulvovaginal candidosis frequently follows use of vaginal or systemic antibiotics. All antimicrobials seem to exert this effect. Vaginal colonisation rates increase from about 10% to 30%. Antibiotics predispose women to vulvovaginal candidosis by eliminating the protective bacterial flora, thus allowing candida overgrowth in the gastrointestinal tract, vagina, or both. It is commonly hypothesized that the reduction of lactobacilli in the vaginal tract predisposes women to VVC. ( Lactobacilli play a key role in the vaginal flora through the production of hydrogen peroxide, bacteriocins and lactic acid which protect against invasion or overgrowth of pathogenic species). Predisposing factors & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Behavioural factors The incidence of vulvovaginal candidosis increases dramatically in the second decade of life, corresponding with the onset of sexual activity. Occurrence peaks in the third decade of life, declining in women older than 40 years, until the permissive effect of oestrogen replacement therapy becomes apparent. Sexual transmission of candida organisms can occur during vaginal intercourse. In terms of sexual practices, receptive orogenital sexual intercourse consistently emerges as a risk factor. Predisposing factors & Pathogenesis in VVC Predisposing factors & Pathogenesis in VVC: Candida organisms gain access to the vaginal lumen and secretions mainly from the adjacent perianal area. Yeast cells are capable of producing extracellular proteases and phospholipase . Both blastoconidia and pseudohyphae are capable of destroying superficial cells by direct invasion. Pseudohyphae and hyphae appear during a symptomatic episode. Hyphal elements enhance colonisation. Thus, vulvovaginal candidosis is associated with greater numbers of candida organisms and with hyphal elements. Predisposing factors & Pathogenesis in VVC C. albicans hyphae Budding C. glabrata PowerPoint Presentation: Susceptibility testing was performed on vaginal yeast isolates collected from January 1998 to March 2001 from 429 patients with suspected vulvovaginal candidiasis . Among the 593 yeasts, C. albicans , C. glabrata , C. parapsilosis , C. krusei , C. tropicalis , C. Lusitaniae, Saccharomyces cerevisiae and Trichosporon spp. were isolated. Among different species, elevated fluconazole MICs (>16 µg/ml) were only observed in C. glabrata, C. parapsilosis, S. cerevisiae , and C. krusei (intrinsically fluconazole resistant). Resistance to itraconazole was observed among C. glabrata , C. krusei , S. cerevisiae and C. parapsilosis . Among 84 patients with recurrent episodes, non- albicans species were more common. Identification : All specimens were plated on CHROMagar (Hardy Diagnostics, Santa Maria, CA) to ensure detection of mixed infections. Cultures were incubated for 72 h at 35°C in ambient air. Identification was based on colony morphology and carbohydrate assimilation using Vitek YBC cards ( bioMerieux Vitek , Inc., Hazelwood, MO). If the identity of the yeast was uncertain, isolates were plated on cornmeal agar or sent to a reference laboratory Identification Identification : Identification c c Identification : Non- albicans species were more commonly isolated from the patients with multiple positive cultures than from the patients with a single positive culture. The predominant non- albicans species recovered was C. glabrata . The prevalence of C. glabrata noted among patients with multiple positive cultures was significantly higher than among patients with a single positive culture. The majority of mixed cultures yielded C. albicans and C. glabrata . Three cultures yielded C. albicans and C. krusei and the remaining three mixed cultures yielded C. glabrata , C. tropicalis , and C. albicans ; S. cerevisiae and C. glabrata ; and C. parapsilosis and C. albicans . Identification Identification : Identification Associated with % Recent antibiotic therapy 46.4% Vulvar contact dermatitis 60.7% vulvar vestibulitis 25% Vulvar intraepithelial neoplasia 23.8% Lichen simplex chronicus 21.4% Diabetes 15.5% Depression 10.7% Postmenopausal symptoms treated with Hormone Replacement T herapy 11.9% 84 patients with multiple positive cultures Lower Genital Tract Infection Antifungal susceptibility testing: Susceptibility testing was performed on the banked isolates (isolates were banked in water at room temperature) using a broth microdilution method according to NCCLS guidelines. A 0.1-ml yeast inoculum of 1.5 (±1.0 ) x 10³ cells/ml in RPMI 1640 medium was added to each microdilution well. And the trays were incubated at 35°C for 46 to 50 h in ambient air. The MICs were read as the lowest antifungal concentration with substantially lower turbidity ( 50% ) compared to growth in the antifungal-free growth control well for all agents except nystatin . Nystatin MICs were read as the minimal antifungal concentration with complete inhibition of growth. NCCLS interpretive criteria were applied for fluconazole , itraconazole , and flucytosine . There are no NCCLS breakpoints for the other antifungals tested. Quality control was ensured by testing the NCCLS-recommended quality control strains C. parapsilosis ATCC 22019 and C. krusei ATCC 6258 Antifungal susceptibility testing Antifungals Conc. in µg/ml fluconazole 0.12 to 128 flucytosine 0.06 to 64 nystatin 0.06 to 64 itraconazole , econazole , clotrimazole , miconazole , and ketoconazole 0.007 to 8 Antifungal susceptibility testing: Antifungal susceptibility testing Drugs Resistance fluconazole 3.7% flucytosine 3.0% itraconazole 16.2% The imidazoles ( econazole , clotrimazole , miconazole and ketoconazole ) were active against 94.3 to 98.5% of the isolates (MIC ≤ 1 µg/ml). Nystatin MICs ranged from 1 to 16 µg/ml, with a MIC inhibiting 90% of isolates (MIC 90 ) of 4 µg/ml. Antifungal susceptibility testing: Antifungal susceptibility testing Candida spp. Antifungal agents Fluconazole 3.7% Itraconazole 16.2% Flucytosine 3.0% R S-DD R R C. albicans - - - 3.30% C. glabrata 15.20% 51.80% 74.10% - C. krusei 41.70% 50% 58.30% 8.30% S. cerevisiae - 11.10% 55.60% - C. parapsilosis - 3.30% 3.30% - C. tropicalis - - - 12.50% C. lusitaniae - - - 100% Trichosporon spp - - - 100% All C. krusei isolates should be reported as fluconazole resistant as per NCCLS guidelines PowerPoint Presentation: Response to antifungal therapy among patients with multiple positive cultures was compared to the MICs. The most common antifungal prescribed was fluconazole (3 doses of 200 mg on alternate day). For C. glabrata , boric acid was prescribed (600-mg capsule, intravaginally once daily for 2 weeks). A few patients received intravaginal econazole or clotrimazole (once or twice daily for 14 days). Pt . improved with C. albicans Non- albicans Comment Fluconazole 61.5% 38.5% The exception was two episodes of C. krusei vulvovaginitis with s ymptomatic improvement after fluconazole therapy despite MICs of 32 and 128 µg/ml All C. krusei isolates should be reported as fluconazole resistant as per NCCLS guidelines. PowerPoint Presentation: Response to antifungal therapy among patients with multiple positive cultures was compared to the MICs. The most common antifungal prescribed was fluconazole (3 doses of 200 mg on alternate day). For C. glabrata , boric acid was prescribed (600-mg capsule, intravaginally once daily for 2 weeks). A few patients received intravaginal econazole or clotrimazole (once or twice daily for 14 days). Pt . improved with C. glabrata Comment Boric acid 48.6% There was no attempt to measure in vitro boric acid activity as there are no standardized methods for testing this agent. 4/7 (57.1%) treated with clotrimazole and 4/8(16.2%) treated with econazole were associated with clinical improvement. All of the isolates treated with clotrimazole or econazole had MICs generally considered susceptible (≤ 1 µg/ml). Conclusion : The paucity of predisposing conditions, the diversity among infecting yeast and the predominance of antifungal susceptible C. albicans isolates support a host defect in vaginal mucosal immunity ( Fidel and Sobel , 1996 ) as a key factor in the pathogenesis of recurrent candidal vulvovaginitis . However, the increased prevalence of non- albicans species (42%) with higher azole MICs among patients with multiple positive cultures in this study suggests antifungal resistance may also be an important factor for some patients. The high frequency with which C. albicans was recovered in this study and its azole susceptibility support the continued use of azole agents for empirical therapy of uncomplicated candidal vulvovaginitis . Conclusion Further studies required - : Cultures from patients with recurrent candidal vulvovaginitis should be obtained to detect non- albicans species that are less likely to respond to an azole agent. Prospective studies with control groups are needed to determine the optimal therapy for candidal vulvovaginitis caused by non- albicans species. Further studies required - PowerPoint Presentation: 207 vaginal yeast isolates from pregnant women were tested for susceptibility to 13 antifungal drugs and boric acid Also, 4 virulence factors ( phospholipase & proteinase production, adhesion to vaginal epithelial cells and hemolytic activity) were determined. The isolates were recovered from vaginal samples of patients with acute VVC (AVVC= 73), symptomatic recurrent VVC (RVVC= 89), asymptomatic (RVVC= 27), and those without signs and symptoms ( n=18). C. albicans was the most common species found, followed by C . glabrata , other Candida spp. and Saccharomyces cerevisiae . MICs of Candida spp. of VVC were no different from those of the controls . In addition, Candida isolates derived from patients with AVVC or RVVC produced significantly higher amounts of phospholipase and proteinase compared with the controls. The U.S. FDA definitions for pregnancy risk of drugs: The U.S. FDA definitions for pregnancy risk of drugs Category Definitions Antifungal drugs Pregnancy Category A Not a risk to the fetus in all trimesters topical vaginal form of NYS Pregnancy Category B risk cannot be ruled out CLO, TER and AMB Pregnancy Category C positive evidence of risk, teratogenic or embryocidal effects ECO, KET, MICO, SUL, TIO, FLU, ITR, 5-FU and CAS Pregnancy Category D contraindicated in pregnancy, but may be acceptable despite the risk Pregnancy Category E contraindicated in women who are or may become pregnant Oral FLU is widely used to treat VVC but it is considered a second-line drug, as it is a Category C agent when used during pregnancy. The fetal toxicity of boric acid (BA) is undetermined Groups of Patients : Groups of Patients Group 1 AVVC Patients with their first or a sporadic episode of symptomatic vulvovaginitis i.e. less than four times a year 73(35% ) Group 2 symptomatic RVVC symptomatic patients with a history of four or more clinical episodes of VVC per year 89 (43%) Group 3 asymptomatic RVVC asymptomatic patients with a history of RVVC 27 (13%) Group 4 controls women who incidentally were found to carry significant numbers of Candida in the vagina, even though they were completely asymptomatic and without a history of RVVC 18 (9% ) The distribution of 207 isolates from pregnant women according to the clinical presentation of yeast vaginitis : The distribution of 207 isolates from pregnant women according to the clinical presentation of yeast vaginitis Antifungal susceptibility testing: The following antifungal agents were tested at the concentrations listed: AMB (0.03 – 16 μg /ml) FLU (0.12 – 128 μg /ml) ITR (0.03 – 16 μ g/ml) KET (0.007 – 8 μ g/ml) NYS (0.06 – 64 μ g/ml) 5-FU (0.06 – 64 μ g/ml) BA (0.82 – 419.84 μ g/ml) CAS (0.03 – 16 μ g/ml) MICO (0.007 – 8 μ g/ml) ECO (0.007– 8 μ g/ml) TIO (0.06– 64 μ g/ml) CLO (0.06– 64 μ g/ml) SUL (0.03 – 16 μ g/ml) TER (0.06 – 64 μ g/ml) Antifungal susceptibility testing Antifungal susceptibility testing: Imidazoles MICO, KET and CLO were active against 98%, 97% and 90% of isolates respectively FLU-resistance and S-DD rates as 1.9% and 6.8% respectively were slightly higher than other studies MIC value for AMB among all Candida isolates tested was 0.5 μg /ml (all susceptible ) For TER, MIC 50 and MIC 90 values were 0.5 – 1 and 1 – 2 μg /ml, respectively,which is not widely used for VVC No resistant strains were detected for 5-FU, while 4.8% of isolates (5 C . albicans , 4 C. glabrata , and 1 C. guilliermondii ) exhibited intermediate susceptibility to 5-FU (MICs of 8 and 16 μ g/ml) Extremely low MIC values were observed for BA (≤ 52.48 μ g/ml) Antifungal susceptibility testing Virulence factors: Adhesion assay The adhesion test was performed as described by Biasoli et al. Detection of secreted aspartyl proteinase Proteinase production was detected using a method described by Rüchel et al. Determination of hemolytic activity Hemolytic activity was assayed using a method described by Luo et al. Determination of phospholipase activity Phospholipase production was assayed according to a method described by Price et al. Virulence factors Virulence factors: Virulence factors Conclusion : Symptomatic (63%) and asymptomatic (59%) RVVC groups were not more adherent to VECs than isolates from the AVVC (58%) and control groups (44%). However, the ability to adhere to VECs was higher for the C . albicans strains than the non- albicans Candida strains. Hemolytic activity showed no significant differences among the organisms in the study groups 1–4 and the lack of a correlation between hemolytic activity and RVVC pathogenesis suggests that this is not a relevant factor for pathogenesis. Results also suggests that proteinase and phospholipase production may have an important role in the pathogenesis of Candida vaginitis . At least 90% of Candida isolates are susceptible to topical imidazoles in vitro; however, these drugs also require clinical trials investigating their use as treatment for infected women during pregnancy. Conclusion Virulence factors: Detection of secreted aspartyl proteinase Proteinase production was detected using a method described by Rüchel et al. The medium was sterilized by filtration and added to autoclaved 2% agar. a single colony ( ∼ 6 mm) of a Candida isolate was inoculated onto bovine serum albumin (BSA) agar. The plates were incubated at 37°C for 5 d. Proteolytic activity ( Pz ) was measured by calculating the ratio of the diameter of the colony to the total diameter of the colony plus the precipitation zone, as described by Price et al. The halo around the colony produced by proteolytic activity of the Candida strain will be referred to as the ‘ precipitation zone’. C. parapsilosis ATCC 22019 served as a negative control. Adhesion assay The adhesion test was performed as described by Biasoli et al. The VECs were obtained from the vaginas of healthy individuals. 500 μl of yeast suspension 500 μl of the VEC pool incubated at 37°C with agitation for 1 h. filtered through a 20μm pore membrane filter fixed with methanol and stained using the Gram technique. the number of cells that adhered to 100 VECs was counted. The assay protocol was reviewed and approved by the Gazi University Ethical Committee (No: 071/2010) for the use of VECs obtained from healthy women. Virulence factors Virulence factors: Determination of hemolytic activity Hemolytic activity was assayed using a method described by Luo et al. A loopful of the stock culture was streaked onto Sabouraud dextrose agar (SDA) and incubated at 37°C for 18 h. The resultant cultures were harvested and washed with sterile saline, and a yeast suspension with an inoculum size of 10 8 cells/ml was prepared. Ten microliters of this suspension was spot-inoculated on a sugar-enriched sheep blood agar so as to yield a circular inoculation site about 5 mm in diameter. The latter medium was prepared by adding 7 ml of fresh sheep blood ( Oxoid , Madrid, Spain) to 100 ml of SDA supplemented with 3% glucose (final concentration, wt/ vol ). The final pH of the medium so prepared was 5.0 – 6.0. The plates were incubated at 37°C in 5% CO 2 for 48 h. The presence of a distinct translucent halo around the inoculum site, viewed with transmitted light, indicated positive hemolytic activity. The diameters of the zones of lysis and the colony were measured, and this ratio (equal to or larger than 1) was used as a hemolytic index to represent the intensity of the hemolysin production by different Candida species. The assay was conducted in quadruplicate on two separate occasions for each yeast isolate tested. A translucent halo around the inoculum site indicated a positive test for hemolytic activity Virulence factors Virulence factors: Determination of phospholipase activity Phospholipase production was assayed according to a method described by Price et al. SDA medium (20 ml) supplemented with 1 mol/l sodium chloride, 0.005 mol/l calcium chloride, and 8% sterile egg yolk emulsion was poured onto 90 mm diameter plates. A single colony ( ∼ 6 mm) of each yeast isolate was inoculated onto the surface of the medium. The plates were incubated at 37 ° C for 5 d. Phospholipase activity ( Pz ) was measured as described above for the proteinase assay. Candida albicans ATCC 10231 served as a positive control. Virulence factors PowerPoint Presentation: ↑ Estrogen → ↑ Glycogen in vagina → carbon source for candida . The newborn vulva and vagina exhibit the effects of residual maternal estrogens. At birth, the labia majora are well developed and the vaginal mucosa is rich in glycogen. Beginning with menarche estrogen once again matures the structures of the vagina and vulva. Among menstruating women, low vaginal pH is the result of estradiol prompting the release of glycogen from the vaginal walls. Vaginal lactobacilli use glycogen and provides carbon source for candida .