Trichosporon beigelii, an emerging pathogen resistant to amphotericin B.

Trichosporon beigelii caused fatal disseminated infections that were resistant to amphotericin B in two granulocytopenic patients. In vitro susceptibility studies demonstrated that both index strains of T. beigelii were inhibited but not killed by amphotericin B at achievable concentrations in serum. The minimum lethal concentration for both isolates was greater than or equal to 18 micrograms/ml. Five of seven other isolates were found to have a similar pattern of amphotericin B resistance. The fact that the minimum lethal concentration of T. beigelii was many times greater than its MIC was consistent with a resistance pattern of tolerance. We concluded that T. beigelii may be resistant in vitro to amphotericin B and that this in vitro resistance was correlated with refractory, disseminated trichosporonosis in granulocytopenic patients. T. beigelii should be included in the expanding list of amphotericin B-resistant fungi.     

Mapping of MRX81 in Xp11.2-Xq12 suggests the presence of a new gene involved in nonspecific X-linked mental retardation

X-linked nonspecific mental retardation (MRX) accounts for approximately 25% of mental retardation in males. A number of MRX loci have been mapped on the X chromosome, reflecting the complexity of gene action in central nervous system (CNS) specification and function. Eleven MRX genes have been identified, but many other causative loci remain to be refined to the single gene level. In 21 MRX families, the causative gene is located in the pericentromeric region; and we report here the identification by linkage analysis of a further such locus, MRX81. The new MRX locus was identified by two- and multi-point parametric analysis carried out on a large Italian family. Tight linkage of MRX81 to DNA markers ALAS2, DXS991, and DXS7132 was observed with a maximum LOD score of 3.43. Haplotype construction delineates an MRX81 critical region of 8 cM, the smallest MRX pericentromeric interval so far described, between DXS1039 and DXS1216, and placing it in Xp11.2-Xq12. So far, automated sequencing of two candidates in the region, the MRX gene oligophrenin (OPHN1) and the brain-specific ephrinB1 (EFNB1) gene, in DNA from affected males excluded their candidacy for MRX81, suggesting a novel disease gene.     

Multisite reproducibility of colorimetric broth microdilution method for antifungal susceptibility testing of yeast isolates.

MICs of fluconazole and amphotericin B were determined independently for 100 coded yeast isolates by each of six laboratories to determine reproducibility of results by using a colorimetric oxidation-reduction-based broth microdilution test. In addition, each site tested five quality control isolates on at least four different occasions during the study. Results agreed within a three-dilution range (mode +/- 1 log2 dilution) for 96.2% of fluconazole tests and 92.7% of amphotericin B tests. Agreement among tests with the quality control isolates was 99.4% with fluconazole and 98.6% with amphotericin B. These results indicate that the colorimetric microdilution method is reproducible among laboratories.     

Rapid diagnosis of typhoid fever through identification of Salmonella typhi within 18 hours of specimen acquisition by culture of the mononuclear cell-platelet fraction of blood.

Detection of Salmonella typhi in blood by culture of the mononuclear cell-platelet layer was compared with other methods currently used for the diagnosis of typhoid fever. Colonies of S. typhi were present in all mononuclear cell-platelet layer-positive cultures within 18 h of plating and were identified within an additional 10 min by a coagglutination technique. In contrast, identification of all positive cultures by conventional blood culture required 3 days.     

Persistent pulmonary infection with an azole-resistant Coccidioides species.

We report a case of a life-threatening, recurrent, and azole-resistant pulmonary coccidioidomycosis in a patient receiving long-term fluconazole therapy for a history of coccidioidal meningitis. Since this diagnosis, the patient has received weekly amphotericin B for more than four years and remains in remission with a stable serum Coccidioides complement fixation antibody titer.     

Prevalence of thermotolerant Campylobacter in pheasants (Phasianus colchicus)

The present study was undertaken with the aim to evaluate the prevalence of thermotolerant Campylobacter spp. in living pheasants in Italy. To achieve this goal, a total of 240 living pheasants, equally shared between female and male birds, were examined. Thermotolerant Campylobacter spp. was isolated in 104 out of 204 (43.3%) living pheasants analysed. Campylobacter coli (100%) and Campylobacter jejuni (13.5%) were identified by polymerase chain reaction. Adult pheasants showed a significantly higher prevalence value (P < 0.05) than younger pheasants.     

Scedosporium inflatum, an emerging pathogen.

The salient morphologic and physiologic characteristics of 18 isolates of Scedosporium inflatum, a newly reported human pathogen, were compared with those of the morphologically similar fungi Scedosporium apiospermum, Scopulariopsis brevicaulis, and Scopulariopsis brumptii. The formation by S. inflatum of annelloconidia in wet clumps at the apices of annellides with swollen bases was found to be the most useful characteristic in differentiating this potential pathogen.