Three cases of vulvovaginal candidiasis due to Candida nivariensis.

Candida nivariensis is emerging as a highly resistant species of the Candida glabrata complex causing invasive and mucocutaneous infections. In this study, three cases of vulvovaginal candidiasis caused by C. nivariensis are described and identified by Internal Transcribed Spacer 1-2 sequencing. All isolates were susceptible in vitro to anidulafungin, micafungin, caspofungin, 5-flucytosine, posaconazole, voriconazole, itraconazole, amphotericin B, and showed dose-dependent susceptibility to fluconazole. In two patients, three doses of oral fluconazole were effective, while one patient developed clinical fluconazole resistance with a new relapse after 6 months. Increasing the weekly dose of fluconazole showed to be effective in this patient.

Azole non-susceptible C. tropicalis and polyclonal spread of C. albicans in Central Vietnam hospitals.

INTRODUCTION: Candida spp. are responsible for infections ranging from local to systemic, and resistance to antifungal first-line therapy is increasing in non-albicans Candida species. We aimed to determine the etiology of candidiasis and the antifungal resistance of Candida spp. isolated in Hue hospitals, Central-Vietnam. METHODS: Species identification was performed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry supported by fungal internal-transcribed-spacer amplification and sequencing. Antifungal susceptibility testing was performed by disk diffusion method and minimum inhibitory concentrations of azoles, caspofungin, and amphotericin B against C. tropicalis were determined by broth microdilution. Polymorphism of erg11 gene associated with fluconazole resistance was carried out by polymerase chain reaction and sequencing. Multilocus sequence typing (MLST) was used for typing selected C. albicans isolates. RESULTS: Overall, 196 Candida isolates were detected, mostly C. albicans (48%), followed by C. tropicalis (16%), C. parapsilosis (11%), C. glabrata (9%), C. orthopsilosis (6%) and to a lesser extent another eight species. High rates of resistance to fluconazole and voriconazole (18.8%) were observed in C. tropicalis with five isolates co-resistant to both agents. Y132F and S154F missense mutations in the ERG11 protein were associated with fluconazole-resistance in C. tropicalis (67.7%). Resistance to caspofungin was found in one isolate of C. albicans. MLST identified a polyclonal population of C. albicans with multiple diploid sequence types, and with few lineages showing potential nosocomial spread. CONCLUSIONS: Resistance to triazole agents should be considered in C. tropicalis infections in the studied hospitals, and surveillance measures taken to avoid Candida diffusion.

Biliary fascioliasis - A rare differential diagnosis of biliary obstruction.

Fascioliasis is a zoonotic disease caused by Fasciola hepatica or F. gigantica. There are two phases of Fasciola infection. In the acute phase, the patient has a wide spectrum of clinical manifestations while the later phase of infection is usually related to inflammatory changes in the bile duct and the mechanical effects of the worm, which can lead to biliary obstruction. The presence of Fasciola inside the biliary system has rarely been reported in the literature. In this report, we presented a case of bile duct obstruction in a 36-year-old male patient undergoing cholecystectomy for gallstones and with a history of worsening jaundice for one month. Extensive laboratory testing failed to clarify the cause of jaundice. Three living liver flukes were subsequently retrieved from the right hepatic duct and later confirmed as F. gigantica by morphology and internal transcribed spacer (ITS2) sequence analysis.

Nannizzia incurvata in Hue city - Viet Nam: Molecular identification and antifungal susceptibility testing.

BACKGROUND: Nannizzia incurvata, a species belonging to the Nannizzia gypsea complex, is considered a neglected pathogen. OBJECTIVE: To detected N. incurvata isolates from dermatophytosis patients in Hue city - Viet Nam, and test the antifungal susceptibility of this species. Moreover, fungal capability to produce hydrolytic enzymes was evaluated. METHODS: Patients' samples were collected and cultured on Sabouraud-chloramphenicol-cycloheximide medium. Dermatophytes isolates were initially macroscopically and microscopically identified. ITS PCR-RFLP and ITS rDNA sequences were performed to determine and confirm species. An ITS Neighbor-Joining phylogenetic tree evaluated the genetic relationship among isolates. Fungal hydrolytic enzymes were examined, including lipase, phospholipase and protease. Antifungal susceptibility testing was carried out by the disk diffusion method. MICs of itraconazole, voriconazole, and terbinafine against these isolates were determined by the broth microdilution method. RESULTS: Twelve isolates of N. gypsea complex were preliminary morphologically identified. PCR-RFLP and ITS-rDNA sequencing identified and confirmed dermatophytes as N. incurvata strains, respectively. An evident polymorphism among isolates was highlighted in the phylogenetic tree. All isolates showed the activity of lipase, phospholipase, and protease production. Overall, all N. incurvata isolates were susceptible to itraconazole, voriconazole, clotrimazole, miconazole, and terbinafine. Few isolates were susceptible to griseofulvin, and none of them were susceptible to fluconazole. CONCLUSIONS: There was a presence of polyclonal N. incurvata isolates in dermatophytosis patients from Hue city, identified by PCR-RLFP and confirmed by ITS sequencing. We confirmed PCR-RLFP as a reliable technique to identify this species. Azole and terbinafine are the optimal choices for N. incurvata treatment except for fluconazole.

First detection of Trichophyton indotineae causing tinea corporis in Central Vietnam.

Trichophyton indotineae, a new species of dermatophytes, has become a significant concern in treating dermatophytosis due to the high level of terbinafine resistance reported in this organism. This is the first report of Trichophyton indotineae infection in Central Vietnam. Antifungal susceptibility testing showed that this isolate was susceptible to itraconazole, voriconazole, and terbinafine. Therefore, the patient was successfully treated with oral itraconazole and ketoconazole topical cream.

Molecular Identification and Appraisal of the Genetic Variation of Taenia saginata in Central Regions of Vietnam.

Taenia saginata is a globally distributed tapeworm responsible for human taeniasis due to the ingestion of raw or undercooked beef. T. saginata is present in several Asian countries, including China, Thailand, Lao PDR, Cambodia, and Vietnam, but little is known about its genetic variation. Studying the tapeworm's phylogeographic patterns is crucial to better understanding their association with the geographic distribution of taeniasis/cysticercosis in human populations. In the present study, 38 specimens of this putative species were collected in central regions of Vietnam and analysed using the mitochondrial gene Cytochrome c Oxidase subunit I (COI) as a molecular marker to assess the correct species identification and investigate the level of genetic variation at different geographic scales. Phylogenetic and phylogeographic analyses were carried out on a dataset that included COI sequences from Vietnamese specimens and from all conspecifics available in GenBank to date. The results showed that the collected Vietnamese specimens belonged to the species T. saginata. In Southeast Asia, signs of a possible founder effect were discovered, with the most common haplotypes frequent and present in many countries, except Lao PDR, which shares its most common haplotype only with individuals from Thailand. Remarkably, a unique taxonomic entity was found worldwide, even though the available COI sequences of T. saginata belonging to non-Asiatic countries are, at present, limited. Therefore, future studies including more COI sequences from a higher number of countries and the use of a combined molecular approach with multiple genetic markers would be useful to provide deeper insight into the global genetic variation of this species.

Clinical impact of the two ART resistance markers, K13 gene mutations and DPC3 in Vietnam.

BACKGROUND: In Vietnam, a rapid decline of P. falciparum malaria cases has been documented in the past years, the number of Plasmodium falciparum malaria cases has rapidly decreased passing from 19.638 in 2012 to 4.073 cases in 2016. Concomitantly, the spread of artemisinin resistance markers is raising concern on the future efficacy of the ACTs. An evaluation of the clinical impact of the artemisinin resistance markers is therefore of interest. METHODS: The clinical effectiveness of dihydroartemisinin-piperaquine therapy (DHA-PPQ) has been evaluated in three districts characterized by different rates of ART resistance markers: K13(C580Y) mutation and delayed parasite clearance on day 3 (DPC3). Patients were stratified in 3 groups a) no markers, b) one marker (suspected resistance), c) co-presence of both markers (confirmed resistance). In the studied areas, the clinical effectiveness of DHA-PPQ has been estimated as malaria recrudescence within 60 days. RESULTS: The rate of K13(C580Y) ranged from 75.8% in Krong Pa to 1.2% in Huong Hoa district. DPC3 prevalence was higher in Krong Pa than in Huong Hoa (86.2% vs 39.3%). In the two districts, the prevalence of confirmed resistance was found in 69.0% and 1.2% of patients, respectively. In Thuan Bac district, we found intermediate prevalence of confirmed resistance. Treatment failure was not evidenced in any district. PPQ resistance was not evidenced. Confirmed resistance was associated to the persistence of parasites on day 28 and to 3.4-fold higher parasite density at diagnosis. The effectiveness of malaria control strategies was very high in the studied districts. CONCLUSION: No treatment failure has been observed in presence of high prevalence of ART resistance and in absence of PPQ resistance. K13(C580Y) was strongly associated to higher parasitemia at admission, on days 3 and 28. Slower parasite clearance was also observed in younger patients.

Evaluation of a Commercial Enzyme-Linked Immunosorbent Assay Kit and In-House Fasciola gigantica Cysteine Proteinases-Based Enzyme-Linked Immunosorbent Assays for Diagnosis of Human Fascioliasis.

Fascioliasis, caused by Fasciola hepatica and Fasciola gigantica infection, is a major food-borne trematodiasis in many places of the world, with the central region of Vietnam being reported as a highly endemic area. Stool examination for Fasciola eggs is not a sensitive method, and immunodiagnostic methods are preferable. We investigated various enzyme-linked immunosorbent assays (ELISAs) to evaluate their efficacy for fascioliasis diagnosis. Test sera used are primarily screened using an ELISA kit produced in Vietnam (VN kit; Viet Sinh Chemical Producing & Trading Co. Ltd., Ho Chi Minh City, Vietnam): Seropositive individuals having symptoms compatible with fascioliasis were regarded as clinically diagnosed fascioliasis cases. A commercial Fasciola IgG ELISA kit from Diagnostic Automation/Cortez Diagnostics, Inc. (USA kit; Woodland Hills, CA), which has been commonly used in Vietnam, was assessed and compared with in-house ELISA systems, including a cystatin-capture (CC) ELISA using crude worm extract (CWE) and an indirect ELISA using a synthetic peptide Ac-TPTCHWECQVGYNKTYDEE-NHMe designed from the F. gigantica cathepsin B (FgCB5) molecule. The USA kit was suitable for routine diagnosis after recalibration of the manufacturer's suggested cutoff point. Cystatin-capture ELISA with CWE provided good sensitivity and specificity with perfect agreement to the results of the USA kit. In dot-blot ELISA, recombinant FgCB5 reacted more strongly with human antisera than did other F. gigantica antigens tested. Enzyme-linked immunosorbent assay using the synthetic peptide fragment of the FgCB5 exhibited nearly 80% sensitivity and specificity, but the test results showed low agreement with CC-ELISA or the USA kit. In conclusion, the commercially available Fasciola IgG ELISA kit from the United States and the in-house CC ELISA using CWE are suitable for practical diagnosis for fascioliasis.

Prevalence of Trichomonas vaginalis infection in symptomatic and asymptomatic women in Central Vietnam.

INTRODUCTION: The diffusion of trichomoniasis in Vietnam has been scarcely studied. The aim of this study was to investigate the prevalence of trichomoniasis in a group of symptomatic and asymptomatic women in Central Vietnam. Relationships between education, socioeconomical and marital status, and sexual behavior with infection have also been investigated. METHODOLOGY: 249 symptomatic and 534 asymptomatic women from Hue City, Vietnam, were enrolled in this study. All women were interviewed about socioeconomical and behavioral status. They underwent clinical examination, and vaginal swabs were taken to assess T. vaginalis infection by wet mount microscopy examination. In addition, an ELISA test to detect antibodies to T. vaginalis in patients' sera was used. RESULTS: The overall prevalence of trichomoniasis assessed by microscopic examination was 6.6%. A significant difference between symptomatic and asymptomatic groups was observed, resulting in 19.3% and 0.7%, respectively. Anti- T. vaginalis antibodies were detected in 31.3% of symptomatic and in 13.3% of asymptomatic women. High-risk sexual behaviour, residence in urban areas, and low level of education were positively associated with infection. CONCLUSION: This is the first report on the diffusion of trichomoniasis in Central Vietnam on symptomatic and asymptomatic subjects. Data demonstrated that T. vaginalis is a common cause of vaginal infection in the Hue province. The prevalence detected by microscopic examination was high in symptomatic subjects, while serological ELISA test detected infection also in asymptomatic patients, who tested negative by microscopy. The ELISA test may be useful to detect infection, especially in asymptomatic population.

Kinetics of circulating antibody response to Trichomonas vaginalis: clinical and diagnostic implications.

OBJECTIVES: Persistence of antibodies against pathogens after antimicrobial treatment is a marker of therapy failure or evolution to a chronic infection. The kinetics of antibody production decrease following antigen elimination is highly variable, and predicting the duration of soluble immunity in infectious diseases is often impossible. This hampers the development and use of immunoassays for diagnostic and seroepidemiological purposes. In the case of Trichomonas vaginalis infection, the kinetics of antibody levels decrease following therapy has never been studied. We thus investigated the clearance of circulating anti-T. vaginalis IgGs after pharmacological treatment in patients affected by trichomoniasis. METHODS: 18 female patients affected by acute trichomoniasis were enrolled in this study. After metronidazole therapy administration, subjects were followed up monthly up to 5 months, and serum levels of anti-T. vaginalis IgGs were measured by ELISA. RESULTS: We showed that a successful therapy is characterised by a relatively fast decline of specific antibodies, until turning into negative by ELISA in 1-3 months. In a few patients we observed that the persistence of anti-T. vaginalis antibodies was associated with an evolution to chronic infection, which may be due to treatment failure or to reinfection by untreated sexual partners. CONCLUSIONS: Our results describe the direct correlation between the decline of a specific humoral anti-T. vaginalis response and an effective antimicrobial therapy. These findings may facilitate the follow-up approach to circumvent limitations in developing new diagnostic tools and techniques routinely used in microbiology laboratories to assess the presence of T. vaginalis in clinical samples.

Cladophialophora bantiana and Candida albicans mixed infection in cerebral abscess of an HIV-negative patient.

Cladophialophora bantiana is a black fungus recorded rarely as a cause of brain abscess. We describe the first case seen in Vietnam. A 35-year-old, previously healthy male, HIV negative, came to the hospital with a clinical diagnosis of brain tumor. He underwent surgery to remove the well-delineated circumscribed lesion. Pathology, directed physical examination and mycological examination revealed an abscess due to Cladophialophora bantiana, and Candida albicans. After two weeks of treatment with Fluconazole 400 mg per day intravenously, the clinical response remained unsatisfactory. Therapy was then withheld per the family's request.