Emergence of Trichosporon mycotoxinivorans (Apiotrichum mycotoxinivorans) invasive infections in Latin America

We report the first two cases of Trichosporon mycotoxinivorans infections in Latin America. We also conducted a literature review and a microbiological investigation, including that of clinical and environmental isolates. A 30-year-old man with chronic renal failure had disseminated infection after dialysis and a 15-year-old boy with cystic fibrosis (CF) had pulmonary exacerbations with positive respiratory samples. A review of the relevant literature revealed that deep-seated infections were related to immunosuppression or invasive devices, while most of the CF patients showed a decline in lung function after positive cultures. Phylogenetic analyses revealed three distinct circulating genotypes. MALDI-TOF mass spectrometry analysis showed similar spectral profiles and correctly identified all strains/isolates. Biofilm production was documented in a bloodstream isolate and biofilm-producing cells showed high minimum inhibitory concentrations against antifungals.

Antifungal activities of tacrolimus in combination with antifungal agents against fluconazole-susceptible and fluconazole-resistant Trichosporon asahii isolates

ABSTRACT The antifungal activity of tacrolimus in combination with antifungal agents against different fungal species has been previously reported. Here we report the in vitro interactions between tacrolimus and amphotericin B, fluconazole, itraconazole, and caspofungin against 30 clinical isolates of both fluconazole-susceptible and fluconazole-resistant Trichosporon asahii. For these analyses, we used the broth microdilution method based on the M27-A3 technique and checkerboard microdilution method. Tacrolimus showed no activity against T. asahii strains (minimal inhibitory concentrations, MICs > 64.0 µg mL−1). However, a larger synergistic interaction was observed by the combinations tacrolimus + amphotericin B (96.67%) and tacrolimus + caspofungin (73.33%) against fluconazole-susceptible isolates. Combinations with azole antifungal agents resulted in low rates of synergism for this group (fluconazole + tacrolimus = 40% and itraconazole + tacrolimus = 10%). Antagonistic interactions were not observed. For the fluconazole-resistant T. asahii group, all tested combinations showed indifferent interactions. The synergism showed against fluconazole-susceptible T. asahii isolates suggests that the potential antifungal activity of tacrolimus deserves in vivo experimental investigation, notably, the combination of tacrolimus with amphotericin B or caspofungin.

Clinical significance of the isolation of Candida species from hospitalized patients

In this study, we isolated and phenotypically identified 108 yeast strains from various clinical specimens collected from 100 hospitalized patients at three tertiary hospitals in São Luís-Maranhão, Brazil, from July to December 2010. The isolates were analyzed for their susceptibility to four of the most widely used antifungal agents in the surveyed hospitals, amphotericin B, fluconazole, 5-flucytosine and voriconazole. The species identified were Candida albicans (41.4%), Candida tropicalis (30.1%), C. glabrata (7.4%), Candida parapsilosis (5.5%), Candida krusei (4.6%), Cryptococcus neoformans (4.6%), Trichosporon spp. (3.7%), Candida norvegensis (0.9%), Rhodotorula glutinis (0.9%) and Pichia farinosa (0.9%). A higher isolation rate was observed in the following clinical specimens: urine (54 isolates; 50%), respiratory tract samples (21 isolates; 19.4%) and blood (20 isolates; 18.6%). Candida albicans isolates were 100% sensitive to all antifungal agents tested, whereas Candida krusei and Crytococcus neoformans displayed intermediate resistance to 5-flucytosine, with Minimal Inhibitory Concentration (MIC) values of 8 mg/mL and 16 mg/mL, respectively. Both strains were also S-DD to fluconazole with an MIC of 16 mg/mL. C. tropicalis was resistant to 5-flucytosine with an MIC of 32 μg/mL. This study demonstrates the importance of identifying the yeast species involved in community and nosocomial infections.

Isolation and antifungal susceptibility testing of Trichosporon asahii in Ceará, Brazil / Isolamento e teste de susceptibilidade aos antifúngicos de Trichosporon asahii no Ceará, Brasil

Trichosporon spp. are yeasts capable of causing invasive disease, which mainly affect immunocompromised patients. A clinical strain of T. asahii was isolated from the blood cultures of patients admitted to the General Hospital of Fortaleza. Susceptibility tests were conducted by disk diffusion and broth microdilution. The isolated strain of T. asahii was resistant to fluconazole. The patient used amphotericin B and caspofungin in order to facilitate the microbiological cure. It was the first isolation and identification of T. asahii in blood culture in Ceará, Brazil.

Trichosporon spp. são leveduras capazes de causar doença invasiva, que afetam principalmente pacientes imunocomprometidos. Uma cepa clínica de T. asahii foi isolada em hemocultura de paciente internado no Hospital Geral de Fortaleza. Os testes de suscetibilidade foram realizados por difusão em disco e microdiluição em caldo. A cepa isolada do T. asahii foi resistente ao fluconazol, o paciente fez uso de anfotericina B e caspofungina então a cura microbiológica ocorreu. Foi o primeiro isolamento e identificação de T. asahii em hemocultura no Ceará, Brasil.

Role of yeasts as nosocomial pathogens & their susceptibility to fluconazole & amphotericin B.

A total of 213 and 208 yeasts were isolated as nosocomial pathogens from various infected specimens during 1996 and 1997 respectively. Yeasts ranked fifth among uropathogens in both the years and from eighth to eleventh in other specimens. Increasing trend in nosocomial urinary tract yeast infection (11.9 in 1996 to 12.6 in 1997) and decreasing trend in wound and other infections (5.1 in 1996 to 2.9 in 1997) per 1000 patients' discharges were observed; blood stream infection remained unchanged (2/1000 discharges) in both the years. Eighty two (41 from each year) randomly selected yeasts were identified to species level following standard protocol and tested for antifungal susceptibility against fluconazole and amphotericin B by reference broth macrodilution technique and agar dilution (AD) method. The frequency of various yeast species identified was Candida albicans 39 (47.6%), C.tropicalis 29 (35.4%), C. krusei 4 (4.9%), C. glabrata 3 (3.7%), C. zeylanoides 2 (2.4%), C. guilliermondii 2 (2.4%), one strain (1.2%) each of C. kefyr, C. parapsilosis, and Trichosporon beigelii. Resistance to fluconazole (MIC > or = 64 micrograms/ml) as per NCCLS criteria was observed in 2 Candida sp. (2.4%). Significantly higher number of non-albicans Candida sp. (8/43; 18.6%) had MIC > 8 micrograms/ml as compared to C. albicans (2/39; 5.1%) (P < 0.05). Only one strain of C. tropicalis had MIC 8 micrograms/ml to amphotericin B and none had MIC > 8 micrograms/ml. Agreement between the reference and the AD methods for fluconazole was 88 per cent and for amphotericin B was 94 per cent. The present study indicates that Candida sp. are emerging as important nosocomial pathogens and the tendency of yeasts to develop resistance to antifungal agents appears to be a challenge for patient management.