Influence of staphylococcal metabolites on adhesive reactions in the system "Candida albicans-buccal epitheliocytes"

The influence of S. aureus and S. epidermitidis metabolites on the adhesive reactions in the system "C. albicans-buccal epitheliocytes" was studied. The study revealed that the treatment of C. albicans with S. aureus supernatants inhibited the adhesion of C. albicans to epitheliocytes, the degree of the inhibiting action of S. aureus supernatants in the system depending on their strain specificity. S. epidermitidis supernatants produced no adhesive effect. The irreversible decrease of the adhesive activity of C. albicans under the action of bacterial metabolites was, seemingly, the consequence of transformation of the receptor apparatus of C. albicans. At the same time S. aureus supernatants produced no essential influence on the adhesive potential and viability of buccal epitheliocytes.     

Antiadhesive effect of the secretion of the oral cavity in the system "Candida albicans--buccal epitheliocytes"

The influence of the oral cavity secretion on adhesive reactions in the system "C. albicans--buccal epitheliocytes" was studied. The treatment of C. albicans with natural saliva led to decrease of adhesive activity. The treatment of C. albicans with antibody absorbed saliva at different temperature conditions led to different changes of adhesion. This effect was determined by the action of temperature-dependent and temperature-independent factors, supposedly of enzymatic nature.     

Role of nuclear factor-kappaB in providing interactions of human neutrophils and epithelial cells from oral cavity with Candida albicans

Contribution of intracellular signal pathways associated with nuclear factor kappaB (NF-kappaB) in realization of interactions of human neutrophils and epithelial cells from oral cavity with Candida albicans was studied. Supression of NF-kappaB in epitheliocytes resulted in decreased adsorption of C. albicans to buccal cells (buccal mucosa). Inhibition of NF-kappaB led to decrease in receptor-dependent oxidative activity of neutrophils in systems with native and IgG-opsonized C. albicans as well as to increase of phagocytic activity during contact with C3b-/iC3b-opsonized C. albicans. It has been concluded that NF-kappaB participates in regulation of specific interactions of neurophils and epitheliocytes with C. albicans.     

Cytohistologic and ultrastructural characteristics of the early stages of the interaction of Candida with epitheliocytes

Cyto-histological and ultrastructural features of the initial stages of the interaction between Candida cells and epitheliocytes of human and animal mucous membranes were studied in vitro and in vivo. The population of epitheliocytes is heterogeneous in its adhesive properties, 15-20% of cells being several times more adhesive than the rest of the population. Within an individual epitheliocyte the adhesion of blastospores was nonuniform, the majority of the latter attaching to the periphery of the cell and to the intercellular boundaries. This was found in cytological smears, histological film preparations and in SEM micrographs, and was also confirmed by the results of morphometric analysis. Ultrastructural analysis has revealed two phases of the interaction between Candida blastospores and epitheliocytes during adhesion, as well as the cytological effect of the fungal cells.     

Adherence of Candida albicans and Candida dubliniensis to buccal and vaginal cells

Twenty-seven Candida albicans strains and 26 Candida dubliniensis strains, isolated from HIV patients, were tested for their adherence to buccal and vaginal epithelial cells. Both species showed important levels of adhesion to buccal and vaginal epithelial cells, although C. albicans showed the highest levels of adhesion. These results suggest that both Candida species are well adapted, in terms of adhesion capability, to the oral and vaginal environment.     

乳杆菌优良菌株的筛选及对小鼠阴道白假丝酵母菌过度增殖干预

目的探讨乳杆菌优良菌株的筛选及其对小鼠阴道白假丝酵母菌过度增殖干预作用。方法对德氏乳杆菌DM8909菌株进行诱变筛选,得到耐抗生素突变株208,以ICR小鼠为实验对象,用甲硝唑进行小鼠阴道菌群脱污染,将白假丝酵母菌接种到小鼠阴道内,构建小鼠阴道白假丝酵母菌过度增殖模型。采用阴道接种德氏乳杆菌DM8909突变株208菌液（2×108CFU/mL）处理,取其阴道冲洗液进行阴道菌群分析,并进行阴道上皮细胞的电镜检查。结果乳杆菌干预后显著清除阴道内的假丝酵母菌,肠杆菌恢复正常水平,与模型组比较,差异有统计学意义（P〈0.05）。结论德氏乳杆菌DM8909抗性菌株208能调整白假丝酵母菌在小鼠阴道内定植,对小鼠阴道上皮细胞有恢复作用。     

Candida biotypes isolated from clinical specimens in Malaysia

The distribution of Candida species was examined using 1114 yeasts isolated from various clinical specimens. The isolates were identified by germ tube test, hyphal/pseudohyphae and chlamydoconidia production and carbohydrate assimilation test using ten carbohydrates (glucose, sucrose, trehalose, cellobiose, arabinose, galactose, mannitol, raffinose, lactose and maltose). Among the 1114 isolates studied, 9 species of Candida were identified and the relative frequency of isolation was C. albicans (44.2%), C. parapsilosis (26.0%), C. tropicalis (17.7%), C. glabrata (9.6%), C. krusei (1.2%), C. rugosa (0.6%), C. guilliermondii (0.2%), C. lusitaniae (0.08%) and C. kefyr (0.08%). Non- C. albicans was the most common Candida species isolated from blood, respiratory system, urine and skin. The isolate from vaginal swabs was predominantly C. albicans. 82.2% of C. glabrata and 64.2% of C. krusei isolated in this study were from vaginal swabs. This revised version was published online in August 2006 with corrections to the Cover Date.     

Biotypes of Candida albicans using the API 20C system

Abstract A total of 130 isolates of Candida albicans obtained from oral, vaginal and skin sites, were biotyped using the API 20C sugar assimilation system. One major biotype accounted for 75% of the isolates, while 12 minor biotypes accounted for the rest. The API 20C system may therefore be useful in supplementing other biotyping schemes of C. albicans available at present.     

妇肤康喷雾剂对阴道常见微生物增殖影响的体外研究

目的体外了解妇肤康喷雾剂溶液对阴道常见的益生乳杆菌和致病菌的影响,为阴道感染疾病提供药物应用的理论依据,指导临床用药。方法对从中国健康妇女阴道分离的乳杆菌、ATCC阴道来源的加德纳菌和白色念珠菌进行体外培养,以中药制剂妇肤康喷雾剂作为培养基,通过绘制生长曲线,评价妇肤康溶液对阴道常见微生物的影响。结果妇肤康实验组中,乳杆菌和白色念珠菌生长曲线随着时间延长轻微下降。加德纳菌在15h后可完全杀灭。结论体外培养时,妇肤康溶液轻微抑制乳杆菌生长,其能够抑制白色念珠菌生长,可以杀灭加德纳菌。     

Animal models of mucosal Candida infection

Rodent models of oral, vaginal and gastrointestinal Candida infection are described and discussed in terms of their scientific merits. The common feature of all experimental mucosal Candida infections is the need for some level of host immunocompromise or exogenous treatment to ensure quantitatively reproducible disease. A growing literature describes the contributions of such candidiasis models to our understanding of certain aspects of fungal virulence and host response to mucosal Candida albicans challenge. Evidence to date shows that T-lymphocyte responses dominate host immune defences to oral and gastrointestinal challenge, while other, highly compartmentalized responses defend vaginal surfaces. By contrast the study of C. albicans virulence factors in mucosal infection models has only begun to unravel the complex of attributes required to define the difference between strongly and weakly muco-invasive strains.     

Adherence of Candida to mucosal epithelial cells

Adherence abilities of 45 Candida strains to human buccal and vaginal epithelial cells in vitro were tested in two media: 0.9% saline and phosphate buffer. Candida albicans cells adhered more strongly to epithelial cells than fungal cells of other Candida species. These findings were statistically significant according to Mann-Whitney's "U" test with buccal epothelial cells in both of the test media and with vaginal cells in saline only.     

Study of acute vulvovaginitis in sexually active adult women, with special reference to candidosis, in patients of the Francisco J. Muñiz Infectious Diseases Hospital

The results of microbiological vaginal secretions samples obtained from 749 women (from July 2001 to July 2002) were studied in the Bacteriology Unit of the Francisco Javier Mu?iz Hospital from Buenos Aires. All patients suffered acute vulvovaginitis were child bearing and sexually active women, 334 of them were HIV-positive. The following are the results of the microbiological studies: Lactobacillus spp 50.6%, Gardnerella vaginalis 25.6%, Candida spp 17.4%, Trichomonas vaginalis 5.3%, Neisseria gonorrhoeae 0.3% and B group Streptococcus 0.8%. Candida vaginitis was significantly more frequent in HIV-positive patients, (21.6% vs 14%; p = 0.0086); meanwhile, trichomoniasis was less common although the difference was not statistically significant (3.6 vs 6.7%, p = 0.0810). The following Candida species were isolated in this study: Candida albicans 76.8%, Candida glabrata 15.6%, Candida parapsilosis 2.9%, Candida tropicalis 1.5% and Candida krusei 0.7%. Eight cases (6.2%) of vaginitis were produced by two Candida species (C. albicans and C. glabrata), and in three cases (2.17%) Saccharomyces cerevisiae were isolated. Five women suffering acute vaginitis with Candida spp presented another etiologic agent of vaginal infection, three cases T. vaginalis and two cases G. vaginalis. The following are some of the most important findings of this study: 1) Half of the patients presented a normal microbial biota; 2) Candida spp vaginitis was significantly more frequent among HIV-positive women; 3) we observed a high incidence of Candida glabrata infections (15.9%), 4) 6.2% of vaginal candidiasis were caused by more than one Candida species and, 5) the susceptibility pattern of C. albicans and C. glabrata isolates against fluconazole was similar to the one observed in other studies. The majority of C. albicans isolates were susceptible to fluconazole (MIC90 = 0.5 microg/ml) meanwhile C. glabrata strains were much less susceptible to this drug (MIC50 and MIC90 = 32 microg/ml).     

Identification and susceptibility against fluconazole and albaconazole of 100 yeasts' strains isolated from vaginal discharge

Vulvovaginal candidiasis is a condition that affects a great number of fertile women. It is considered the second cause of genital infection after vaginosis due to GAM complex. Candida albicans is the most frequent isolated species from vaginal discharge. However, sometimes more than one yeast species could be found in the same clinical sample that are more resistant to antifungal drugs. Nowadays, it is necessary to identify properly up to species level the isolated microorganism and to determine the antifungal susceptibility profile. One hundred strains obtained from vaginal discharge of 94 patients suffering acute vulvovaginal candidiasis were studied. The identification of the isolates showed: C. albicans 86%, Candida glabrata 6%, Candida inconspicua 3%, Candida krusei 2% and Candida intermedia, Candida holmii and Trichosporon asahii one case each. Minimal inhibitory concentrations (MIC) of all the yeasts against fluconazole and albaconazole were performed. C. glabrata, C. krusei and C. inconspicua were the most resistant against fluconazole, on the other hand albicans was susceptible to this drug. All the isolates presented MIC against albaconazole much lower than fluconazole.     

Candida albicans Niche Specialization: Features That Distinguish Biofilm Cells from Commensal Cells

The fungus Candida albicans is a frequent commensal colonizer of the human gastrointestinal (GI) tract, but is also an opportunistic pathogen. This review explores features that distinguish the colonizing and pathogenic forms of C. albicans. Candida albicans in a biofilm is used as an example of a pathogenic form of the organism, because biofilms are a common feature of device-associated C. albicans infections. Biofilms (complex, sessile communities of cells) have been the subject of several large-scale gene expression studies. Biofilms and commensal C. albicans colonizing the murine GI tract show a variety of differentially expressed genes. Cell surface proteins encoded by these differentially expressed genes are especially attractive as targets for new clinical prevention, diagnosis, or treatment tools that are specific for C. albicans in its pathogenic biofilm state.     

Karyotyping of Candida albicans and Candida glabrata isolates from recurrent vaginal infections by pulsed-field gel electrophoresis

In the present study, 16 women with recurrent vulvovaginal candidiasis (RVVC) due to Candida albicans and Candida (Torulopsis) glabrata were followed for a period of 4 to 12 months, and 36 vaginal isolates were evaluated by pulsed-field gel electrophoresis (PFGE). Eleven women were infected by C. albicans and 5 by C. glabrata. Three electrophoretic karyotypes of C. albicans and 3 of C. glabrata were identified throughout the follow-up. All patients but one was infected with the same karyotype of C. albicans or C. glabrata during the follow-up period. Two different karyotypes of C. glabrata were identified in one patient in the course of 12 months. The results confirmed the diversity of the karyotypes of C. albicans and C. glabrata causing vulvovaginitis, and demonstrated the persistence of colonization with the same strain over different periods of time despite therapy (15/16 women).     

Quantitative and qualitative analyses of the cell death process in Candida albicans treated by antifungal agents

The death process of Candida albicans was investigated after treatment with the antifungal agents flucytosine and amphotericin B by assessing morphological and biophysical properties associated with cell death. C. albicans was treated varying time periods (from 6 to 48 hours) and examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). SEM and AFM images clearly showed changes in morphology and biophysical properties. After drug treatment, the membrane of C. albicans was perforated, deformed, and shrunken. Compared to the control, C. albicans treated with flucytosine was softer and initially showed a greater adhesive force. Conversely, C. albicans treated with amphotericin B was harder and had a lower adhesive force. In both cases, the surface roughness increased as the treatment time increased. The relationships between morphological changes and the drugs were observed by AFM clearly; the surface of C. albicans treated with flucytosine underwent membrane collapse, expansion of holes, and shrinkage, while the membranes of cells treated with amphotericin B peeled off. According to these observations, the death process of C. albicans was divided into 4 phases, CDP(0), CDP(1), CDP(2), and CDP(4), which were determined based on morphological changes. Our results could be employed to further investigate the antifungal activity of compounds derived from natural sources.     

Phenotypic evaluation to differentiate Candida albicans from Candida dubliniensis

This study evaluated the phenotypic tests used to differentiate Candida albicans from Candida dubliniensis. A total of 55 isolates from vaginal secretions, oral cavity and hemoculture were studied. They were originally identified as C. albicans, based on their morphological and physiological characteristics. These isolates were tested for colony color development on CHROMagar Candida medium, growth at 45 degrees C on Sabouraud Dextrose agar, lipolytic activity on Tween 80 Agar medium and colony morphology and chlamydoconidia formation on Staib agar medium. Of the 55 isolates studied, seven yielded one or more phenotypic characteristics suggestive of Candida dubliniensis. These isolates were tested by PCR with specific primers for Candida dubliniensis and API ID 32. The seven isolates were confirmed as Candida albicans. All of these finding indicate that DNA based tests should be used for definitive identification of Candida dubliniensis.     

Prevalence of specific and phylogenetically closely related genotypes in the population of Candida albicans associated with genital candidiasis in China

Genitourinary candidiasis, which is most frequently caused by Candida albicans, is a common problem worldwide. The pathogenesis of the infection, especially recurrence of the infection, remains to be elucidated. This study analyzed 199 independent Chinese C. albicans isolates using multilocus sequence typing (MLST) and microsatellite typing, with the focus on the isolates associated with vulvovaginal candidiasis (VVC) of Chinese women. MLST data of 221 vaginal isolates from other countries available from the consensus MLST database of C. albicans were retrieved for comparison. A total of 124 diploid sequence types (DSTs) were recognized from the Chinese C. albicans isolates, among which, 98 (79.0%) have not been reported in the MLST database of the species. The majority of the VVC (71.6%) and balanitis (92.3%) isolates from China were located in clade 1 of C. albicans; while only 40.6% of the vaginal isolates and 7.8% of the oral isolates from healthy volunteers were found in the same clade. Furthermore, 69.1% of the VVC and 84.5% of the balanitis isolates concentrated in a cluster of clade 1 with DST 79 as the primary founder. The isolates in this cluster possessed microsatellite genotypes CAI 30-45, CAI 32-46 and their close derivatives. Interestingly, a remarkable difference in genotype distribution patterns between Chinese and non-Chinese vaginal isolates of C. albicans was observed. Only 11.3% of the non-Chinese vaginal isolates compared were located in the cluster concentrated with Chinese VVC isolates. The results suggest significant association of specific and genetically similar genotypes with genital infections in China.     

The distribution frequency of Candida species in the genitourinary tract among symptomatic individuals in Nigerian cities

A clinical survey was carried out in seven cities in the southern part of Nigeria to determine the relative distribution of genitourinary Candida species in symptomatic patients reporting for diagnosis and treatment. Seven Candida species were identified using the CHROMagar Candida method and the API 20C System. Candida species were represented by Candida glabrata (33.7%), Candida albicans (20.1%), Candida tropicalis (18%), Candida guilliermondii (17.8%) Candida pseudotropicalis (5%), Candida parapsilosis (5%), and C. albicans var.stellatoidea (1.2%). The distribution of these species among the various age groups (15-20, 21-25, 26-30, 31-35, 36-40 and 41 plus years) was statistically insignificant. Out of the 517 positive samples, 182 (35%) were found in the age group 26-30 years, while age 41 plus had the lowest frequency (1.2%). The results presented show that C. albicans, usually reported to be the most frequently isolated species, is not the main species in the cities studied. With C. glabrata in preponderance, the finding supports recent studies reporting that several pathogenic non-C. albicans species are now being frequently isolated. The level of social activities, such as drug abuse and sexual promiscuity, may be important in the distribution frequency of Candida species in different age groups and locations.