Phylogenetic analysis of Trichophyton mentagrophytes human and animal isolates based on MnSOD and ITS sequence comparison

Dermatophytes are keratinophilic fungi able to infect keratinized tissues of human or animal origin. Among them, Trichophyton mentagrophytes is known to be a species complex composed of several species or variants, which occur in both human and animals. Since the T. mentagrophytes complex includes both anthropophilic and zoophilic pathogens, accurate molecular identification is a critical issue for comprehensive understanding of the clinical and epidemiological implications of the genetic heterogeneity of this complex. Here, 41 T. mentagrophytes isolates from either human patients (14 isolates) or animals (27 isolates) with dermatophytosis were prospectively isolated by culture and identified on morphological bases at the University Hospital Centres of Lille and Poitiers, and the Veterinary School of Alfort, respectively. The isolates were differentiated by DNA sequencing of the variable internal transcribed spacer (ITS) regions flanking the 5.8S rDNA, and of the housekeeping gene encoding the manganese-containing superoxide dismutase (MnSOD), an enzyme which is involved in defence against oxidative stress and has previously provided interesting insight into both fungal taxonomy and phylogeny. ITS1-ITS2 regions and MnSOD sequences successfully differentiate between members of the T. mentagrophytes complex and the related species Trichophyton rubrum. Whatever the phylogenetic marker used, members of this complex were classified into two major clades exhibiting a similar topology, with a higher variability when the ITS marker was used. Relationships between ITS/MnSOD sequences and host origin, clinical pattern and phenotypic characteristics (macroscopic and microscopic morphologies) were analysed.

Use of a high-density DNA probe array for detecting mutations involved in rifampicin resistance in Mycobacterium tuberculosis

A Mycobacterium high-density DNA probe array designed to detect rpoB mutations conferring rifampicin resistance in Mycobacterium tuberculosis was evaluated. The rpoB hybridisation patterns produced by 41 susceptible (RifS) and 59 rifampicin-resistant (RifR) clinical isolates of M. tuberculosis were compared with the results of conventional dideoxynucleotide sequencing of the rpoB gene. For all the RifR isolates, the rpoB hybridisation patterns correlated with the rpoB sequencing results. Among the 59 isolates, 11 distinct amino-acid changes were detected by the DNA probe array. Of these, 36 (61%) corresponded to replacement of the serine residue found in position 531 (S531L in 34 isolates and S531W in two isolates), 16 (27%) affected histidine 526 (five H526D, five H526Y, four H526L, one H526N and one H526R), four (6.8%) replaced aspartate 516 with a valine, and one (1.7%) replaced glutamine 513 with a leucine. Deletion of the asparagine residue at position 519 was detected in one isolate susceptible to rifampicin, but yielding c. 0.1% resistant colonies on rifampicin-containing medium. No mutation was detected in the rpoB region from one isolate yielding c. 5% of resistant colonies on rifampicin-containing medium. Finally, a D516Y substitution was detected in association with an unexpected mutation, G523W, not tiled on the DNA probe array, but which could be detected by analysing the hybridisation pattern obtained with the wild-type probes covering codon 523. In conclusion, the Mycobacterium probe array is a promising approach to rapid detection of mutations involved in rifampicin resistance in M. tuberculosis.

Successful outcome of disseminated Fusarium infection with skin localization treated with voriconazole and amphotericin B-lipid complex in a patient with acute leukemia

A disseminated Fusarium oxysporum infection with skin localization was diagnosed in a woman with a relapse of B-acute leukemia during induction chemotherapy. The infection was refractory to amphotericin B-lipid complex alone but responded successfully when voriconazole was added.

[Distribution of respiratory arrests in preterm and term infants (author's transl)]

Incidence, distribution and periodicity of respiratory arrests larger than or equal to 2 seconds duration were studied in relation to age and sleep states by means of polygraphic recording in 61 tracing of 44 preterm and term infants free of pathologic conditions known to increase the risk of respiratory arrests. Respiratory arrests at any infant's age were found to be more frequent during active sleep. Incidence of respiratory arrests decreases with age in all sleep states. At any age the average duration of respiratory arrest is longer in quiet sleep. When restrictive definition is applied periodic breathing was found to be a rare and probably an abnormal phenomenon not in connection with any particular sleep state. Apneas of longer than 10 seconds duration were observed rather seldon, as well as cardiac slowing coinciding with respiratory arrest or apnea. Bradypnea and poor differenciation of breathing pattern according to sleep states represent a rare and presumably abnormal finding. The authors feel that the elements observed should be considered in estimating the risk of severe apnea in infants.