Posaconazole enhances the activity of amphotericin B against hyphae of zygomycetes in vitro.

The in vitro activity of posaconazole plus amphotericin B against conidia and hyphae of 30 clinical zygomycetes was investigated. The combination of posaconazole with amphotericin B was found to be significantly more synergistic (40%) against hyphae (P < 0.05) than against conidia (10%). Antagonism was not observed.

Lack of evidence of endosymbiotic toxin-producing bacteria in clinical Rhizopus isolates.

Infections by Rhizopus spp. account for about 90% of zygomycoses, many of which are lethal in immunocompromised patients. We recently noted that several strains of Rhizopus microsporus harbour rare bacterial endosymbionts (Burkholderia sp.) for the production of 'mycotoxins', which might play a role as virulence factors in human Rhizopus infections. In this study eight clinical Rhizopus spp. isolates have been investigated for the presence of toxin-producing bacterial endosymbionts. By metabolomic data, PCR targeting bacterial 16S rDNA and microscopic investigations with fluorescence dyes we provide three lines of evidence showing that the fungal strains are not associated with endofungal bacteria. Consequently, toxin-producing bacteria are not essential for Rhizopus infections and the development of zygomycoses in humans.

Epidemiology and antifungal susceptibilities of Candida spp. to six antifungal agents: results from a surveillance study on fungaemia in Germany from July 2004 to August 2005.

OBJECTIVES: Data on fungal infections occurring in Germany are rare to date. The aim of the present study was to survey the epidemiological situation in Germany, to provide data on the susceptibility of the fungal isolates to antifungals. METHODS: Five hundred and sixty-one Candida isolates were collected from primarily sterile sites of patients from July 2004 to August 2005 with the aid of a nationwide established laboratory network, MykolabNet-D. The MICs of amphotericin B, flucytosine, fluconazole, itraconazole, voriconazole and caspofungin were determined using the microdilution reference procedure M27-A2 of the CLSI. RESULTS: Candida albicans was the most frequently isolated species (58.5%), followed by Candida glabrata (19.1%), Candida parapsilosis (8.0%) and Candida tropicalis (7.5%). In contrast, the isolation rate of Candida krusei (1.4%) was low. Candida kefyr appeared as a new pathogen in this profile. Amphotericin B revealed excellent activity, with only three resistant isolates (0.5%). A total of 25 isolates (4.5%) showed resistance against flucytosine. All 25 isolates were identified as C. tropicalis indicating a peculiarity within German isolates. The resistance rate of all tested isolates to fluconazole and to itraconazole was 3.7% and 17.6%, respectively. According to the provisional breakpoints, two isolates (0.4%) were tested as resistant to voriconazole. Caspofungin was active against the majority of isolates where an intrinsic resistance is unknown. CONCLUSIONS: This latest German survey of isolates from patients with fungaemia demonstrates a favourable situation with respect to antifungal susceptibilities for the antifungal substances tested.

Characterization of an extracellular subtilisin protease of Rhizopus microsporus and evidence for its expression during invasive rhinoorbital mycosis.

An endoprotease Arp (alkaline Rhizopus protease) was identified and purified to virtual homogeneity from the culture supernatant of an isolate of Rhizopus microsporus var. rhizopodiformis recovered from a non-fatal case of rhinoorbital mucormycosis. N-terminal sequencing of the mature native enzyme was obtained for the first 20 amino acids and revealed high homology to serine proteases of the subtilisin subfamily. Arp migrated in SDS-PAGE with an estimated molecular mass of 33 kDa and had a pI determined to be at pH 8.8. Arp is proteolytically active against various substrates, including elastin, over a broad pH range between 6 and 12 with an optimum at pH 10.5. After invasive mucormycosis, specific antibodies against Arp were detected in stored serum samples taken from the patient from whom the R. microsporus strain of this study had been isolated. Furthermore, in search of factors involved in thrombosis as a typical complication of mucormycosis, a procoagulatory effect of the enzyme has recently been shown. Altogether, these data substantiate the expression of Arp during human rhinoorbital mucormycosis and suggest a role of the enzyme in pathogenesis.

A case of pulmonary aspergillosis with lack of response to caspofungin.

Currently, susceptibility testing of Aspergillus isolates towards caspofungin is hampered by a lack of interpretative cut-off values. Nevertheless, caspofungin has been widely recommended for the treatment of invasive aspergillosis. This antifungal, however, could lead to therapy failure as demonstrated by the case in this report of a 55-year-old patient, who eight months after the diagnosis of leukemia and successful allogenic hematopoietic stem cell transplantation (HSCT), succumbed to a fatal pulmonary aspergillosis infection, which resisted treatment with caspofungin.

Fatal Aspergillus myocarditis following short-term corticosteroid therapy for chronic obstructive pulmonary disease.

A 58-y-old man with chronic obstructive pulmonary disease (COPD) was admitted for treatment of an acute exacerbation of his illness. The patient's condition initially improved after therapy with oxygen, bronchodilators, antibiotic and methylprednisolone (40 mg every 8 h) was started. Soon afterwards, however, the patient's clinical status deteriorated and he died on the fifth hospital day. Post-mortem examination revealed unsuspected, isolated fungal myocarditis. The fungus was later identified as Aspergillus by indirect immunofluorescence. To our knowledge, this is the first case of fatal Aspergillus myocarditis related to short-term (< 1 week) steroid therapy in a COPD patient. We believe that this case provides further evidence to support the possibility of life-threatening infections in COPD patients who receive even a short course of corticosteroid treatment.