agar and Aspergillosis

The emergence of azole-resistant Aspergillus fumigatus isolates is a matter of significant concern in Europe, with countries reporting resistance rates (which can be as high as 30%) in hospitalized patients. Consequently, the treatment guidelines in The Netherlands, the country with the highest documented prevalence of azole-resistant A. fumigatus, has just been revised to now recommend initial therapy with combination therapy until the susceptibility pattern is known. Therefore, susceptibility testing of clinically relevant isolates has been strongly recommended in the ESCMID-EFISG aspergillosis guidelines. Furthermore, mixed azole-susceptible and azole-resistant (isogenic as well as non-isogenic) infections have been reported to occur, which implies that colonies of clinical cultures may harbour various phenotypes of azole susceptibility.. The EUCAST-AFST (European Committee on Antimicrobial Susceptibility Testing Subcommittee on Antifungal Susceptibility Testing) has released a new screening method document (E.Def 10.1) for the detection of azole-resistant A. fumigatus isolates and updated the QC tables for antifungal susceptibility testing with associated QC endpoints. This review described in detail how to perform the screening test.. This "How to document" is based on the EUCAST azole agar screening method document E.Def 10.1 and the QC tables for antifungal susceptibility testing document, v 2.0 (available at http://www.eucast.org/ast_of_fungi/qcafsttables/) CONTENTS: The method is based on the inoculation of azole-containing and azole-free agars and visual determination of fungal growth after one and two days of incubation. It can easily be implemented in routine laboratories of clinical microbiology and has been validated for simultaneous testing of up to five A. fumigatus colonies using itraconazole and voriconazole (mandatory), and posaconazole (optional).. This easy-to-use screening procedure for the detection of azole resistance in clinical A. fumigatus isolates will allow rapid testing in the daily routine of the microbiology laboratory and thus facilitate earlier appropriate therapy.

Topics: Agar; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Azoles; Culture Media; Drug Resistance, Fungal; Humans; Mass Screening; Microbial Sensitivity Tests; Netherlands; Practice Guidelines as Topic

Hyphal growth in filamentous fungi proceeds in an unidirectional radial pattern from a point inoculation. An inhibitor produced, secreted, and absorbed by the advancing hyphae has been speculated to account for directional growth. Working with Mucor and Aspergillus, laboratory evidence is provided for the production of an inhibitory by the advancing hyphae of these filmentous fungi that precludes back growth. Strains of Mucor and Aspergillus inoculated in agar on a 0.45-mm membrane filter placed on agar surfaces grow radially beyond the filter perimeter and onto the agar surface. Removal of the filter pad does not result in hyphal extension back into the clear zone underlying the membrane filter. Inoculation of the clear zone with a fresh Mucor or Aspergillus spore suspension does not result in hyphal growth. Instead, germinating spores show aberrant and aborted hyphae. The fungal inhibitor shows cross-reactivity between Mucor and Aspergillus, is resistant to pronase (10 mg/mL) but not chloroform inactivation, and passes through dialysis tubing with a molecular weight cutoff of 3500.

Topics: Agar; Antifungal Agents; Aspergillosis; Aspergillus; Culture Media; Humans; Micropore Filters; Mucor; Mucormycosis

Topics: Agar; Aspergillosis; Asthma; Celiac Disease; Eczema; Food Hypersensitivity; gamma-Globulins; Hemosiderosis; Humans; Immunodiffusion; Immunoglobulin G; Immunoglobulin M; Larva Migrans, Visceral; Liver Cirrhosis; Lung Diseases; Methods; Multiple Myeloma; Rhinitis, Allergic, Seasonal

Topics: Agar; Amebicides; Antifungal Agents; Aspergillosis; Candidiasis; Dermatomycoses; Drug Synergism; Humans; Microsporum; Quinolines; Resorcinols; Tinea