Search

Yeast-like filamentous fungi, collected in Italy from 1985 to 2018, were submitted to molecular identification and antifungal susceptibility testings. Clinical isolates were identified as Magnusiomyces capitatus (28), M. clavatus (18), and Geotrichum candidum (2). M. clavatus was prevalent among blood isolates (18/24), M. capitatus among isolates from other biological materials. The intrinsic echinocandin resistance was confirmed. Both species had low minimum inhibitory concentrations (MICs) of itraconazole, posaconazole, and voriconazole, while M. clavatus had lower MIC of flucytosine and higher MIC of isavuconazole than M. capitatus. The intrinsic resistance of these species to echinocandins could be the reason of the recent increase of M. clavatus bloodstream infections., (© The Author(s) 2018. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology.)

Background: ST22-IV is a successful hospital-associated MRSA clone. Due to its known ability to replace other MRSA clones in hospitals, it became a dominant clone in Europe and beyond. So far, there are no studies investigating the relationship between the epidemiological success of MRSA clones and their capacity to withstand commonly encountered stresses., Methods: We investigated the fitness of ST22-IV in comparison with the replaced clone ST228-I, evaluating its resistance to oxidative stress, autolytic activity, growth at high osmolarity and in acid and alkaline environments and survival under desiccation and heat shock. We also compared their phenotypic characteristics and examined the impact of antibiotic consumption on epidemiological success., Results: Here we demonstrate that the dominance of ST22-IV is linked neither to changes in antibiotic consumption nor to acquisition of additional resistances over time. Strong α-haemolysin activity, the production of β-haemolysin and the presence of an active agr could partly explain the virulence of ST22-IV previously observed in a murine model of pneumonia. Most importantly, we show that ST22-IV compared with ST228-I, besides retaining susceptibility to most antibiotics over time, has a superior capacity to survive under all stress conditions tested, which bacteria commonly face during their life cycle., Conclusions: Our results support our hypothesis that ST22-IV has a fitness advantage over ST228-I. This fitness advantage could have allowed ST22-IV to displace ST228-I without acquiring additional resistances and could help explain its epidemic success in hospital settings and its spread in Europe and beyond., (© The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)