Molecular identification of Veronaea botryosa by use of amplified fragment length polymorphism, including in vitro antifungal susceptibility profile

H. Badali, G. S. de Hoog, C. H. W. Klaassen and J. F. Meis


Introduction: Invasive mould infections caused by dematiaceous fungi are rare but increasingly recognized in human disease. Veronaea botryosa once considered a rare pathogen, has increasingly encountered in human disorders ranging from chromoblastomycosis, phaeohyphomycosis either cutaneously or sub-cutaneously and disseminated infections which mostly has been isolated from patients from different geographical regions during the last decades. Veronaea botryosa show differences in levels of resistance to antifungal agents. Therefore, it is important to be able to correctly identify the causative organism to the species level. Therefore, the purpose of this study is insight into V. botryosa epidemiology, demonstrating the existence of genetic diversity among isolates from different patients and in vitro antifungal susceptibility of 9 antifungal against V. botryosa strains. Material and
Methods: MICs were determined for AmB, FLU, ITC, VOC, POS, ISA, TER and MECs for CAS and ANID based on CLSI M38- A2 guidelines. Inoculum was adjusted spectrophotometrically (530 nm) to optical densities that ranged from 0.17–0.15 in RPMI 1640 MOPS broth. Plates were incubated at 35 _C for 72 h. Drug and fungus free controls were included
Results: AFLP patterns exhibited very clear differences among V. botryosa with other related species. The resulting MIC90s for V. botryosa strains were as follows, in increasing order: POS (0.25 mg l- 1); ITC (1 mg l-1); VOC (4 mg l-1); TER (4 mg l-1); ANID (8 mg l-1); CAS (8 mg l-1); AmB (16 mg l-1); ISA (16 mg l-1) and FLU (64 mg l-1). On the basis of these in vitro results and the findings of previous clinical and animal studies, posaconazole seems to be a good alternative to other drugs. The new agent Isavuconazole, which is also available as an intravenous preparation, has poor activity against V. botryosa.
Conclusion: AFLP might prove to be a reliable method for the identification of V. botryosa against other related strains which is very essential in antifungal susceptibility methods. Posaconazole and itraconazole were the most active drugs with high in vitro activity against V. botryosa. From the echinocandins tested CAS and ANID demonstrated poor in vitro activity, those drugs might not be useful for treating a range of severe fungal infections, either alone or as part of a combination therapy regimen. However their clinical effectiveness in the treatment of cerebral infection remains to be determined.

abstract No: 

    • ISHAM 18th (2012)