Alternative Identification Test Relying upon Sexual Reproductive Abilities of Candida lusitaniae Strains Isolated from Hospitalized Patients

The in vitro mating ability of Candida lusitaniae (teleomorph Clavispora lusitaniae) clinical isolates has been investigated. Studying the effects of culture conditions, we showed that ammonium ion depletion in the medium is a major trigger of the sexual cycle. Moreover, a solid support is required for mating, suggesting a role for adhesion factors in addition to the mating type gene recognition function. Monitoring of mating and meiosis efficiency with auxotrophic strains showed great variations in ascospore yields, which appeared to be strain and temperature dependent, with an optimal range of 18 to 28 degrees C. The morphogenetic events taking place from mating to ascospore release were studied by scanning and electron microscopy, and the ultrastructure of the conjugation canal, through which intercellular nuclear exchanges occur, was revealed. Labeling experiments with a lectin-fluorochrome system revealed that the nuclear transfer was predominantly polarized, thus allowing a distinction between the nucleus donor and the nucleus acceptor strains. The direction of the transfer depended on the strain combination used, rather than on the genotypes of the strains, and did not appear to be controlled by the mating type genes. Finally, we demonstrated that all of the 76 clinical isolates used in this study were able to reproduce sexually when mated with an opposite mating type strain, and we identified a 1:1 MATa/MATalpha ratio in the collection. These results support the idea that there is no anamorph state in C. lusitaniae. Accordingly, the mating type test, which is easy to use and can usually be completed within 48 h, is a reliable alternative identification system for C. lusitaniae.     

Epidemic Spread of Multidrug-Resistant Tuberculosis in Johannesburg,South Africa

Numerous reports have documented isolated transmission events or clonal outbreaks of multidrug-resistant Mycobacterium tuberculosis strains, but knowledge of their epidemic spread remains limited. In this study, we evaluated drug resistance, strain diversity, and clustering rates in patients diagnosed with multidrug-resistant (MDR) tuberculosis (TB) at the National Health Laboratory Service (NHLS) Central TB Laboratory in Johannesburg, South Africa, between March 2004 and December 2007. Phenotypic drug susceptibility testing was done using the indirect proportion method, while each isolate was genotyped using a combination of spoligotyping and 12-MIRU typing (12-locus multiple interspersed repetitive unit typing). Isolates from 434 MDR-TB patients were evaluated, of which 238 (54.8%) were resistant to four first-line drugs (isoniazid, rifampin, ethambutol, and streptomycin). Spoligotyping identified 56 different strains and 28 clusters of variable size (2 to 71 cases per cluster) with a clustering rate of 87.1%. Ten clusters included 337 (77.6%) of all cases, with strains of the Beijing genotype being most prevalent (16.4%). Combined analysis of spoligotyping and 12-MIRU typing increased the discriminatory power (Hunter Gaston discriminatory index [HGDI] = 0.962) and reduced the clustering rate to 66.8%. Resolution of Beijing genotype strains was further enhanced with the 24-MIRU-VNTR (variable-number tandem repeat) typing method by identifying 15 subclusters and 19 unique strains from twelve 12-MIRU clusters. High levels of clustering among a variety of strains suggest a true epidemic spread of MDR-TB in the study setting, emphasizing the urgency of early diagnosis and effective treatment to reduce transmission within this community.     

EORTC 26083 phase I/II trial of dasatinib in combination with CCNU in patients with recurrent glioblastoma

The treatment of patients with recurrent glioblastoma remains a major oncologic problem, with median survival after progression of 7–9 months. To determine the maximum tolerated dose and dose-limiting toxicity (DLT), the combination of dasatinib and cyclonexyl-chloroethyl-nitrosourea (CCNU) was investigated in this setting. The study was designed as multicenter, randomized phase II trial, preceded by a lead-in safety phase. The safety component reported here, which also investigated pharmacokinetics and preliminary clinical activity, required expansion and is therefore considered a phase I part to establish a recommended dosing regimen of the combination of CCNU (90–110 mg/m²) and dasatinib (100–200 mg daily). Overall, 28 patients were screened, and 26 patients were enrolled. Five dose levels were explored. DLTs, mainly myelosuppression, occurred in 10 patients. Grade 3 or 4 neutropenia was recorded in 7 patients (26.9%) and thrombocytopenia in 11 patients (42.3%). No significant effect of CCNU coadministration on dasatinib pharmacokinetics was found. Median progression-free survival (PFS) was 1.35 months (95% confidence interval: 1.2–1.4) and 6-month PFS was 7.7%. In this phase I study of recurrent glioblastoma patients, the combination of CCNU and dasatinib showed significant hematological toxicities and led to suboptimal exposure to both agents.     

Population genetics of Trypanosoma brucei gambiense,the agent of sleeping sickness in Western Africa

Human African trypanosomiasis, or sleeping sickness caused by Trypanosoma brucei gambiense, occurs in Western and Central Africa. T. brucei s.l. displays a huge diversity of adaptations and host specificities, and questions about its reproductive mode, dispersal abilities, and effective size remain under debate. We have investigated genetic variation at 8 microsatellite loci of T. b. gambiense strains isolated from human African trypanosomiasis patients in the Ivory Coast and Guinea, with the aim of knowing how genetic information was partitioned within and between individuals in both temporal and spatial scales. The results indicate that (i) migration of T. b. gambiense group 1 strains does not occur at the scale of West Africa, and that even at a finer scale (e.g., within Guinea) migration is restricted; (ii) effective population sizes of trypanosomes, as reflected by infected hosts, are probably higher than what the epidemiological surveys suggest; and (iii) T. b. gambiense group 1 is most likely a strictly clonally reproducing organism.     

Urinary 5-HIAA in migraine: Evidence of lowered excretion in young adult females

Urinary 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were determined in 44 young adult migraine patients (35 women, 9 men) between attacks and in 33 healthy controls (23 women, 10 men). HVA excretion was equivalent in all groups. 5-HIAA was unaltered in men but was significantly decreased in female migraine patients when compared with their sex-matched controls (-31%, p less than 0.01). No relationship was found between 5-HIAA excretion and the various characteristics of migraine, such as the time that had elapsed since the last attack and the presence or absence of oral contraception. The relatively marked decrease in 5-HIAA excretion in female migraine patients can hardly be accounted for by a reduction in either neuronal or platelet serotonin metabolism alone. A reduction in the intestinal contribution to urinary 5-HIAA might be the crucial factor.