First report of cryptococcosis due to Cryptococcus gattii sensu stricto VGI in an Ivorian HIV negative patient.

INTRODUCTION: Cryptococcus gattii species complex is endemic to tropical and subtropical regions and is described as a causative agent of cryptococcosis in immunocompetent individuals. CASE PRESENTATION: We describe the first case of cryptococcosis in a HIV-negative patient from Ivory Coast infected by Cryptococcus gattii sensu stricto VGI. Isolates were recovered from cerebrospinal fluid (CSF) prior to systemic antifungal treatment up to 42 days after detection of the presence of yeasts in the CSF. Eighteen isolates were recovered, genetic diversity and antifungal susceptibility analyses were performed. All the isolates belonged to the Cryptococcus gattii sensu stricto (B;VGI) and were identified as a new sequence type (ST) 553 by Multilocus Sequence Typing (MLST) analyses. Susceptibility testing showed that all the strains had a wild-type phenotype for fluconazole, amphotericin B and flucytosine. Treatment with fluconazole (1200mg/day) was initiated with success. CONCLUSION: This is the first case report of the presence of C. gattii sensu stricto VGI in a HIV-negative ivorian patient and the second report of the presence of species from the C. gattii complex species in this country.

African ST173 Cryptococcus deuterogattii strains are commonly less susceptible to fluconazole: An unclear mechanism of resistance.

OBJECTIVES: Fluconazole (FCZ), either alone or in combination, is often administered for treatment of cryptococcal meningitis, especially in sub-Saharan Africa. Its extensive use has led to the emergence of FCZ-resistant strains. The mechanisms underlying FCZ resistance are poorly documented for yeasts belonging to the Cryptococcus gattii species complex. The literature suggests that resistance could be due to mutations in and/or overexpression of the ERG11 gene (encoding the 14-α-demethylase) and efflux pumps such as MDR and AFR (two subclasses of ABC transporters). Here we highlight the presence of genotype VGII strains (Cryptococcus deuterogattii) from the Ivory Coast with a rare sequence type (ST173) associated with high FCZ minimum inhibitory concentrations (MICs) compared with strains originating from the Pacific Northwest (USA). METHODS: Mechanisms of FCZ resistance were investigated in 28 Ivorian clinical C. deuterogattii isolates recovered from three patients during their antifungal treatment and follow-up. RESULTS: The results demonstrated that: (i) these strains exhibited no mutations in the ERG11 gene; (ii) some strains had increased ERG11 and MDR1 mRNA expression, whilst AFR1 and AFR2 were not overexpressed in strains with high FCZ MICs compared with the expression levels for strains with low FCZ MICs; and (iii) exposure to FCZ in strains with high MICs induced AFR1 mRNA overexpression. CONCLUSION: This study demonstrated that the FCZ resistance mechanism commonly described in Cryptococcus neoformans was not responsible for resistance to FCZ in rare subtype strains.

Assessment of caspofungin susceptibility of Candida glabrata by the Etest®, CLSI, and EUCAST methods, and detection of FKS1 and FKS2 mutations.

Candida glabrata has emerged as a major pathogen in invasive candidiasis in recent years. Currently, guidelines for invasive candidiasis treatment recommend fluconazole or an echinocandin as the first-line therapy. Nevertheless, the resistance of Candida glabrata to echinocandin is an emerging problem and has been partly associated with mutations in the FKS1 and FKS2 genes. The Etest® is an appropriate method for determining antifungal susceptibility in emergency routine diagnosis. In this work, we evaluated the reliability of the Etest® in comparison with the two reference broth microdilution methods, Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST), to assess the caspofungin resistance of 193 isolates of Candida glabrata. The interpretation of minimum inhibitory concentration (MIC) values was also discussed according to different breakpoints. Moreover, FKS1 and FKS2 mutations were investigated for isolates with high MICs. Our results showed that the MIC50 value was similar to the MIC90 value for each method. The Etest® method showed the lowest MIC values, whereas EUCAST presented the highest. Categorical agreement between the Etest® and CLSI methods was 100 % and 36 % using the breakpoints proposed by Arendrup et al. (Antimicrob Agents Chemother 56(7):3965-3968, 2012) and Pfaller et al. (Int J Antimicrob Agents 38(1):65-69, 2011), respectively. Two isolates showed high MIC values with the three methods and both presented FKS2 mutations. A novel FKS2 mutation was also reported for one isolate. Future epidemiological studies should also evaluate the reliability of the Etest® to detect echinocandin resistance, as it remains a routine method.

Use of RNAlater as a preservation method for parasitic coprology studies in wild-living chimpanzees.

We evaluated the use of an RNA stabilisation buffer, RNAlater (Ambion, Austin, Texas), as a preservation medium for parasitic coprology analysis of faecal samples collected from chimpanzees living in the wild (Pan troglodytes troglodytes). Thirty faecal samples collected in the forests of south-east Cameroon (Mambele area) from 2003 to 2011 were preserved in RNAlater at -80 °C and analysed for their parasite content. We identified and counted parasitic elements and assessed their shape, size and morphology in relation to the storage time of the samples. We found that parasite elements were identifiable in RNAlater preserved samples after as many as 7 years, showing that RNAlater could be an effective and reliable preservation medium for coprology. Thus, its use could be an interesting way to optimise sample collection for several types of studies (parasitology and bacteriology/virology) at once, especially considering the logistically challenging and time-consuming field campaigns needed to obtain these faecal samples.

Genotyping and antifungal susceptibility testing of Cryptococcus neoformans isolates from Cameroonian HIV-positive adult patients.

Cryptococcus neoformans is the most common cause of meningitis amongst adult Africans with HIV/AIDS. The widespread use of fluconazole may lead to the emergence of isolates with reduced susceptibility. We studied C. neoformans isolates from HIV-infected patients with cryptococcal meningitis. Genotyping and antifungal testing were performed to assess the genetic diversity, occurrence of mixed infections and in vitro activity of antifungal agents. Isolates were recovered from cerebrospinal fluid prior to systemic antifungal treatment. Six isolates were studied for each sample (a total of 114 isolates from 19 patients). Serotyping was performed via LAC 1 and CAP 64 gene amplification and genotyping was performed using phage M13 core, (GACA)4 and (GTG)5 primers and restriction polymorphism analysis of the URA5 gene. Susceptibilities for amphotericin B, flucytosine, fluconazole, voriconazole and posaconazole were tested by the Sensititre YeastOne® method. All strains were identified as C. neoformans var. grubii serotype A. We identified nine major genotypes. Up to two genotypes were identified in the same sample. None of the isolates were resistant to the studied drugs. However, 13 of 114 strains exhibited a reduced susceptibility to fluconazole and 13 of 114 strains exhibited a reduced susceptibility to flucytosine. No correlation was found between the genotype and susceptibility. This study confirms the prevalence of C. neoformans serotype A in Cameroon. Two genotypes may be responsible for a single episode of cryptococcosis. The possibility of mixed infection and diminished susceptibility to fluconazole or flucytosine must be considered for the management of cryptococcosis.

Development of loop-mediated isothermal amplification (LAMP) as a diagnostic tool of toxoplasmosis.

Infection with Toxoplasma gondii is one of the most common parasitic infections in humans and other warm-blooded animals. This paper describes the development of loop-mediated isothermal amplification (LAMP) specific to the single-copy gene SAG1 as a diagnostic tool of toxoplasmosis. A set of primers, composed of outer primers, inner primers and loop primers was designed from a published sequence data (GeneBank Acc. no. AY651825). Experiments showed that when LAMP was applied to sample organs, amplification absolutely required the loop primers to complete. SAG1-based LAMP turned out to be very sensitive, exhibiting a degree of sensitivity higher than the conventional PCR. LAMP is a convenient and sensitive diagnostic tool for routine health control of toxoplasmosis.

Needle exchange use, sexual risk behaviour, and the prevalence of HIV, hepatitis B virus, and hepatitis C virus infections among Bulgarian injection drug users.

At a time when the rates of HIV, hepatitis C virus (HCV), and hepatitis B virus (HBV) infections have risen among injection drug users (IDUs) in other countries in the region, little is known about the prevalence of these infections among Bulgarian injectors and about their sexual risk behaviours. IDUs (n = 773) in a community-based needle exchange programme (NEP) and two major drug treatment facilities in Sofia completed a structured interview and were tested for HIV, HBV, and HCV antibodies. While HCV prevalence in the sample was 73.9%, HBV and HIV prevalence was low -6% and 0.5%, respectively. Having more than 10 sexual partners, having sex with someone with hepatitis C or another IDU, and never using a condom with another IDU were common among those who were recruited through NEP. As 40% of the IDUs reported using NEP, it appears that needle exchange provides an opportunity to reach high-risk populations and prevent sexual transmission of blood-borne pathogens.