The efflux pump inhibitor tetrandrine exhibits synergism with fluconazole or voriconazole against Candida parapsilosis.

In the last two decades, with the wide use of azoles, antifungal resistance among Candida parapsilosis has considered a matter of concern worldwide. The aim of this study is to evaluate the antifungal potentials of tetrandrine (TET) alone and in combination with fluconazole (FLC)/voriconazole (VRC) against C. parapsilosis. Susceptibility tests were performed by microdilution method, checkerboard assay, time-kill test, spot assay. Subsequently, rhodamine 6G efflux test and the expressions of transporter related genes, namely CDR1 and MDR1 for C. parapsilosis were analyzed by qRT-PCR. The susceptibility test showed that TET presented strong synergism with FLC and VRC with fractional inhibitory concentration index (FICI) in a range of 0.094-0.562. The susceptibility results were also confirmed by spot assay and time-kill studies. With TET treatment, a vast quantity of rhodamine 6G could not be pumped out from the cells as considerably intracellular red fluorescence was accumulated. Meanwhile, the expressions of efflux-associated genes presented varying degrees of inhibition. These results indicated that TET was a decent antifungal synergist to promote the antifungal efficacy of FLC/VRC, and the underlying antifungal mechanism might be associated with the inhibition of efflux pump and the elevation of intracellular drug content.

Successful Treatment by Surgery of a Primary Cutaneous Mucormycosis Caused by Mucor irregularis.

We report a case of primary cutaneous mucormycosis caused by Mucor irregularis. A 66-year-old man was presented to our hospital with a history of gradually enlarging plaque on the right leg for about a year. The identification of pathogen based on the fungus morphology and DNA sequencing revealed M. irregularis as the responsible fungus for skin lesion. The lesion was removed incidentally by a surgery procedure, and no recrudescence was seen during a follow-up of 24-month observation.

The first case of phaeohyphomycosis caused by Rhinocladiella basitona in an immunocompetent child in China.

We present the first case of phaeohyphomycosis caused by Rhinocladiella basitona (R. basitona) in China and describe the mycological characteristics of this pathogen. A 11-year-old girl was presented with plaque on her face for 3 years. Diagnosis was based on histopathology, mycology, and molecular identification. The patient was treated with terbinafine and itraconazole. This case is the second of phaeohyphomycosis caused by R. basitona in the world (previously belonging to Geniculosporium).

A simple and reliable PCR-restriction fragment length polymorphism assay to identify Candida albicans and its closely related Candida dubliniensis.

Candida dubliniensis is an emerging pathogen capable of causing superficial as well as systemic infections. Due to its close similarity to C. albcians, conventional methods based on phenotypic traits are not always reliable in identification of C. dubliniensis. In this study, we developed a PCR-restriction fragment length polymorphism (RFLP) assay to identify and discriminate between the two closely related species. The D1/D2 region of 28S rDNA was amplified by PCR and enzymatically digested by ApaI and BsiEI respectively. PCR products of both species were digested into two fragments by ApaI, but those of other yeast species were undigested. BsiEI cut the PCR products of C. albicans into two fragments but not those of C. dubliniensis. Thus two species were differentiated. We evaluated 10 reference strains representing 10 yeast species, among which C. albicans and C. dubliniensis were successfully identified. A total of 56 phenotypically characterized clinical isolates (42 C. albicans isolates and 14 C. dubliniensis isolates) were also investigated for intra-species variability. All tested isolates produced identical RFLP patterns to their respective reference strains except one initially misidentified isolate. Our method offers a simple, rapid and reliable molecular method for the identification of C. albicans and C. dubliniensis.

Direct detection and differentiation of causative fungi of onychomycosis by multiplex polymerase chain reaction-based assay.

A rapid and reliable triplex PCR procedure was developed to detect pathogenic fungi directly from specimens of onychomycosis. One hundred and four patients were included in this study. Of them, forty-five (43.3%) were finally diagnosed with onychomycosis according to the diagnostic criteria. The sensitivity of PCR, microscopy and culture were 93.3%, 100% and 64.4%, respectively; the specificities were 100%, 86.4% and 100%, respectively; the positive predictive values were 100%, 84.9% and 100%, respectively; the negative predictive values were 95.2%, 100% and 78.7%, respectively. This molecular diagnostic process could distinguish the 3 groups of pathogens in onychomycosis (dermatophyte, yeast and mold) and could be completed within 8 h. This multiplex PCR assay could used in laboratories with no mycological specialization for rapid etiologic diagnosis and treatment selection, especially in suspected fungus cases if they can not be detected by conventional methods or if a rapid diagnosis of onychomycosis is needed.

In vitro evaluation of phospholipase, proteinase, and esterase activities of Candida parapsilosis and Candida metapsilosis.

The aim of this study is to characterize extracellular phospholipase, proteinase, and esterase activities of Candida parapsilosis and C. metapsilosis isolated from clinical sources. Using PCR-restriction fragment length polymorphism (PCR-RFLP) of the secondary alcohol dehydrogenase (SADH) gene fragment, we identified 20 as C. parapsilosis and 11 as C. metapsilosis from 31 isolates of C. parapsilosis species complex. No C. orthopsilosis was identified. A significantly high isolation frequency of C. metapsilosis (35.5%) was observed. Subsequent evaluation of enzymatic profile showed that 90.5% of C. parapsilosis and 91.7% of C. metapsilosis isolates were phospholipase producers. No difference in phospholipase activity was observed between two species. In terms of proteinase, 81.0% of C. parapsilosis and 83.3% of C. metapsilosis isolates were positive. A higher level of proteinase activity was detected in C. parapsilosis. A remarkably high proportion of both C. parapsilosis and C. metapsilosis isolates exhibited strong phospholipase and proteinase activities, suggesting that the production of these two enzymes might be common for them. On the other hand, both species similarly displayed rare esterase activity, with only one C. parapsilosis and two C. metapsilosis isolates being positive. Our data may further add to the confusion concerning the hydrolytic enzymatic activities of the C. parapsilosis complex, and a wider collection of isolates and standardized methods may help to address the issue.

[Effect of phospholipomannan of Candida albicans on the production of interleukin 6 and interleukin 8 in monocytes].

OBJECTIVE: To investigate whether Candida albicans-native phospholipomannan (PLM) induce an inflammation response through Toll-like receptor(TLRé2 in human acute monocytic leukemia cell line (THP-1) cells. METHODS: Human THP-1 monocytes were challenged with PLM in vitro. The mRNA expressions of TLR2, TLR4, proinflammatory cytokine [interleukin(IL)-6], and chemokine (IL-8) were assayed by real time reverse transcription polymerase chain reaction. The secretions of IL-6 and IL-8 were measured by enzyme-linked immunosorbent assay. The expression of TLR2 was analyzed with Western blot. RESULTS: PLM increased the mRNA expressions and secretions of proinflammatory cytokines (IL-6) and chemokines (IL-8) in THP-1 cells (all P=0.0000). PLM up-regulated the mRNA and protein levels of TLR2 (P=0.0000), whereas the mRNA level of TLR4 was not altered. PLM hydrolyzed with ß-D-mannoside manno hydrolase failed to induce gene and protein expressions of TLR2, IL-6, and IL-8. Anti-TLRS-neutralizing antibody blocked the PLM-induced secretions of IL-6 and IL-8 in THP-1 cells (P = 0.0003, P = 0.0010). CONCLUSION: Canidada albicans-native PLM may contribute to the inflammatory responses during Candida infection in a TLR2-dependent manner.

Primary cutaneous zygomycosis caused by rhizomucor variabilis: a new endemic zygomycosis? A case report and review of 6 cases reported from China.

We report a case of primary cutaneous zygomycosis caused by Rhizomucor variabilis and review 6 cases reported from China that share similar features and are different from those cases caused by other species of Mucorales. It is noteworthy that all 6 of the cases were observed in 3 adjacent provinces of eastern China.

Primary cutaneous zygomycosis due to Absidia corymbifera in a patient with cutaneous T cell lymphoma.

A slowly enlarging arm ulcer appeared in a 61-year-old man with cutaneous T cell lymphoma. Skin biopsy revealed aseptate hyphae and nodular small/medium-sized pleomorphic CD4(+) T cell infiltration. Cultures yielded Absidia corymbifera which was identified by phenotypic and molecular methods. Since a thorough examination did not detect organ involvement, the patient was diagnosed as having primary cutaneous zygomycosis. This is the first case report of cutaneous zygomycosis caused by A. corymbifera in a patient with primary cutaneous CD4(+) small/medium-sized pleomorphic T-cell lymphoma. Other cases of primary cutaneous zygomycosis caused by A. corymbifera are also reviewed.

A new medium for diagnosis of dermatophyte infection.

A new medium (DBM) was compared with dermatophyte test medium (DTM) for the diagnosis of dermatophyte infection. The sensitivity was 103 cfu/mL (2 x 101 cfu/slant) for both DTM and DBM with a suspension of Trichophyton rubrum. In axenic cultures, all dermatophytes tested altered the color of both media. Although most non dermatophytic molds made a color change, it was at a slower rate. In nail samples of dermatophyte infection, all dermatophytes altered the color of both media. However, the time for discoloration was shorter with DBM than with DTM (5.83 +/- 0.39 days vs. 7.32 +/- 0.41 days, t = 2.63, P = 0.01). Most isolates of nondermatophyte also made a discoloration, but they could be distinguished from dermatophytes by their colonial diameters when the color began to change (> or = 5 mm). Our results were in good agreement with a professional laboratory of medical mycology, however, the latter is regularly able to differentiate exactly the species of the growing dermatophyte. The DBM medium is more convenient, rapid, more accurate and economical to use than DTM.

Genotype comparisons of strains of Candida albicans from patients with cutaneous candidiasis and vaginal candidiasis.

BACKGROUND: It is uncertain whether genotypes of Candida albicans (C. albicans) are associated with colonizing body locations or variant conditions of infection. The aim of this study was to investigate whether there are significant associations between strain genotypes and body sites of infection and to determine the potential pathogenesis of cutaneous candidiasis at multiple locations. METHODS: A total of 151 strains of C. albicans were isolated from 74 infant patients with cutaneous candidiasis and 61 female patients with vaginal candidiasis. Patients were grouped according to the body sites and underlying conditions of infection. Genotypes were identified by polymerase chain reaction (PCR) of the 25S rDNA and PCR-restriction fragment length polymorphism (RFLP) of ALT repeats digested with EcoRI and Clal. RESULTS: Ten genotypes were detected. There were significant differences in genotype frequencies between the two groups. However, we found no clear association between genotypes and the sites of cutaneous infection or the underlying conditions of vaginal candidiasis (VVC). In addition, strains of C. albicans from multiple cutaneous locations of the same patient had identical genotypes. CONCLUSIONS: Populations of C. albicans from patients with cutaneous and vaginal candidiasis were genetically different. However, the lack of genetic difference between strains from different body sites with cutaneous infections or from different underlying conditions for VVC suggests no evidence of genotype selection for different skin surfaces or patients with different underlying conditions for VVC.

[Establishing an experimental guinea pig model of dermatophytosis Using Trichophyton rubrum].

OBJECTIVE: To construct an animal model infected by Trichophyton rubrum. METHODS: Three different strains of Trichophyton rubrum were separated from clinical specimen for the infection of guinea pigs. Corticosteroids were given before and after the construction of animal model to facilitate the infection. Direct microscopy, culture, and histopathologic methods were adopted to verify the construction. RESULTS: Ten days after the inoculation of Trichophyton rubrum, with the intervention of corticosteroid, the guinea pigs were examined. Prominent scales and inflammation could be seen on the inoculation site of the Trichophyton rubrum infected guinea pig. Scales and hairs of Trichophyton rubrum infected guinea pig dealt with 10% potassium hydroxide, hypha out of the hair and microconidia or hypha in the hair shaft could be seen. Seven days after the inoculation of scales and hair on SDA plate, cultures of Trichophyton rubrum showed that the colonial morphology were identical to the original dermatophytes. PAS staining of infected guinea pig skin tissue showed that hypha and microconidia could be seen in the infundibula and hair root. CONCLUSION: With the intervention of corticosteroid, a stable guinea pig model infected by Trichophyton rubrum were successfully constructed.

[Effects of Malassezia isolates on cytokines production associated with melanogenesis by keratinocytes].

OBJECTIVE: To investigate the co-culture of keratinocytes with Malassezia isolates which cause the pityriasis versicolor with different color and to analyze the changes of cytokines associated with melanogenesis. METHODS: The effects of Malassezia species with different proportions on the growth rate of keratinocytes was assessed with 5 g/L methyl thiazolyl tetrazolium (MTT). Co-culture of keratinocytes and Malassezia species were performed with isolates from hyer- and hypo-pigmentation areas of pityriasis versicolor. The supernatants were collected at different time points, and the changes of basic fibroblast growth factor (b-FGF), endothelin-1 (ET-1), nerve growth factor-beta (NGF-beta), interleukin-1alpha (IL-1alpha), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), stem cell factor (SCF) were recorded. Three control groups were established accordingly. RESULTS: When the ratio between keratinocytes and Malassezia species was lower than 1: 10, the growth rate of keratinocytes was not affected by Malassezia (P > 0.05). When the ratio was increased above 1:20, the growth rate of keratinocytes was significantly inhibited by Malassezia (P < 0.01). The secretions of IL-1alpha, IL-6, TNF-alpha, and ET-1 was significantly increased after the co-culture of keratinocytes and Malassezia (P < 0.01), while those of b-FGF, NGF-beta, and SCF had no significant changes (P > 0.05). Compared with the isolates from the hypo-pigmentation area, ET-1 induced by isolate from hyperpigmentation area significantly increased (P < 0.01). CONCLUSION: When Malassezia isolates are co-cultured with keratinocytes, the secretions of cytokines associated with melanogenesis may differ from each other. ET-1 may play certain role in the hyper-pigmentation of pityriasis versicolor.

Interleukin-22 mediates early host defense against Rhizomucor pusilluscan pathogens.

BACKGROUND: In recent years, the fungal infectious disease zygomycosis has increased in incidence worldwide, especially among the immunodeficient population. Despite the rates of zygomycosis-related death and deformation being very high, the mechanism(s) by which the fungal pathogens cause these severe manifestations remain unknown. METHODS: Using the associated Rhizomucor variabilis species, which can selectively induce cutaneous zygomycosis in otherwise healthy individuals, we investigated the host mechanisms of infection-related responses, including cytokine and chemokine expression as well as contributions of particular T cell subsets. siRNA specifically targeting IL-22,IL-17 and IFN-γ were used to down-regulate expression of those molecules. RESULTS: In mouse models of infection, IL-22 was implicated in development of Rhizomucor spp.-induced skin lesions. In cultured human peripheral blood monocytes, R. pusilluscan, which is often found in immunodeficient patients, induced the production of IL-22, while R. variabilis did not. Moreover, Rhizomucor spp.-induced secretion of Il-22 from CCR6(+)CCR4(+)CCR10(+) cells was down-regulated by knockdown of IL-22 related signaling receptors, RORC and ARH. CONCLUSION: Our data strongly suggest that avoidance of IL-22 may be one mechanism by which mucor species produce morbidity and mortality in infected individuals.

Ecological surveys of the Cryptococcus species complex in China.

BACKGROUND: Despite recent reports on the molecular epidemiology of cryptococcal infections in China, clinical isolates have been mostly reported from human immunodeficiency virus (HIV)-negative patients, and environmental isolates from China have rarely been included. The aim of this study was to investigate the ecological profile of Cryptococcus (C.) neoformans and C. gattii in China. METHODS: A survey was performed in 10 cities from 20°N (North latitude) to 50°N and in a Eucalyptus (E.) camaldulensis forestry farm at the Guixi forestry center, China. RESULTS: Six hundred and twenty samples of pigeon droppings from 10 cities and 819 E. camaldulensis tree samples were collected and inoculated on caffeic acid cornmeal agar (CACA). The brown-colored colonies were recultured to observe their morphology, growth on canavanine-glycine-bromothymol-blue (CGB) medium, phenol oxidase and urease activities, serotype and mating type. There were obvious differences in the positive sample rates of C. neoformans in pigeon droppings collected from the different cities, ranging from 50% in the cities located at latitudes from 30°N - 40°N, 29% at 20°N - 30°N and 13% at 40°N - 50°N. CONCLUSIONS: There were no differences in positive bevy rates (approximately 80%) among the three grouped cities. Mycological tests of 101 isolates purified from pigeon droppings revealed that they were C. neoformans var. grubii. We also observed variable capsular size around the C. neoformans cells in colonies with variable melanin production and the bio-adhesion of the natural C. neoformans cells with other microorganisms. One urease-negative C. neoformans isolate was isolated from pigeon droppings in Jinan city. No C. gattii was isolated in this study.

Insoluble beta-glucan from the cell wall of Candida albicans induces immune responses of human THP-1 monocytes through Dectin-1.

BACKGROUND: beta-glucan is the major structure component of Candida albicans (C. albicans) cell wall. It has been demonstrated that Dectin-1 as the principal C-type lectin pattern-recognition receptor (PRR) can recognize fungal beta-glucan and induce immune responses. In this study, we sought to clarify whether insoluble beta-glucan from the cell wall of C. albicans (CaIG) could induce immune responses in human THP-1 monocytes (a human acute monocytic leukemia cell line) and to determine the underlying mechanisms. METHODS: Human THP-1 monocytes were challenged with CaIG in vitro. The mRNA expression of Dectin-1, Toll-like receptors (TLR2), proinflammatory cytokine (TNF-alpha) and chemokine (IL-8) was assayed by real-time reverse transcription polymerase chain reaction (RT-PCR). The secretion of TNF-a and IL-8 were measured by enzyme-linked immunosorbent assay (ELISA). H(2)O(2) release was determined by microplate fluorescent assay. Western blotting was used to analyze IkappaB-a phosphorylation and degradation. RESULTS: Exposure of THP-1 monocytes to CaIG led to increased gene expression and secretion of TNF-alpha and IL-8. CaIG induced H(2)O(2) release in a time-dependent manner. CaIG hydrolyzed with zymolyase failed to induce gene expression and secretion of TNF-alpha, IL-8 and H(2)O(2) release. CaIG up-regulated the mRNA of Dectin-1, whereas the mRNA level of TLR2 was not altered. THP-1 monocytes challenged with CaIG resulted in the activation of NF-kappaB in a time-dependent manner. Dectin-1 inhibitor laminarin blocked the CaIG-induced production of TNF-alpha and H(2)O(2) in THP-1 monocytes, but no such effect was observed in pretreatment with anti-TLR2 neutralizing antibody and the LPS inhibitor (polymyxin B). CONCLUSION: CaIG may play a role in activation of immune responses in human THP-1 cells through Dectin-1, not TLR2.

A simple and reliable PCR-restriction fragment length polymorphism assay to identify Candida albicans and its closely related Candida dubliniensis

Candida dubliniensis is an emerging pathogen capable of causing superficial as well as systemic infections. Due to its close similarity to C. albcians, conventional methods based on phenotypic traits are not always reliable in identification of C. dubliniensis. In this study, we developed a PCR-restriction fragment length polymorphism (RFLP) assay to identify and discriminate between the two closely related species. The D1/D2 region of 28S rDNA was amplified by PCR and enzymatically digested by ApaI and BsiEI respectively. PCR products of both species were digested into two fragments by ApaI, but those of other yeast species were undigested. BsiEI cut the PCR products of C. albicans into two fragments but not those of C. dubliniensis. Thus two species were differentiated. We evaluated 10 reference strains representing 10 yeast species, among which C. albicans and C. dubliniensis were successfully identified. A total of 56 phenotypically characterized clinical isolates (42 C. albicans isolates and 14 C. dubliniensis isolates) were also investigated for intra-species variability. All tested isolates produced identical RFLP patterns to their respective reference strains except one initially misidentified isolate. Our method offers a simple, rapid and reliable molecular method for the identification of C. albicans and C. dubliniensis.