ABSTRACT
Mucorales are saprobes, ubiquitously distributed and able to infect a heterogeneous population of human hosts. The fungi require robust stress responses to survive in human host. We tested the growth of Mucorales in the presence of different abiotic stress. Eight pathogenic species of Mucorales, including Rhizopus arrhizus, Rhizopus microsporus, Rhizomucor pusillus, Apophysomyces elegans, Licthemia corymbifera, Cunninghamella bertholletiae, Syncephalastrum racemosum and Mucor racemosus, were exposed to different stress inducers: osmotic (sodium chloride and d-sorbitol), oxidative (hydrogen peroxide and menadione), pH, cell wall and metal ions (Cu, Zn, Fe and Mg). Wide variation in stress responses was noted: R. arrhizus showed maximum resistance to both osmotic and oxidative stresses, whereas R. pusillus and M. indicus were relatively sensitive. Rhizopus arrhizus and R. microsporus showed maximum resistance to alkaline pH, whereas C. bertholletiae, L. corymbifera, M. racemosus and A. elegans were resistant to acidic pH. Maximum tolerance was noted in R. microsporus to Cu, R. microsporus and R. arrhizus to Fe and C. bertholletiae to Zn. In contrast, L. corymbifera, A. elegans and M. indicus were sensitive to Cu, Zn and Fe respectively. In conclusion, R. arrhizus showed high stress tolerance in comparison to other species of Mucorales, and this could be the possible reason for high pathogenic potential of this fungi.
Subject(s)
Mucorales/drug effects , Mucorales/physiology , Rhizomucor/physiology , Rhizopus/physiology , Stress, Physiological , Humans , Hydrogen-Ion Concentration , Metals/pharmacology , Mucorales/growth & development , Osmotic Pressure , Oxidative Stress , Rhizomucor/drug effects , Rhizomucor/growth & development , Rhizopus/drug effects , Rhizopus/growth & development , Rhizopus/immunology , Vitamin K 3/pharmacologyABSTRACT
Human infection due to Nocardiopsis, an actinomycete, is rare and the majority of those infections are due to Nocardiopsis dassonvillei. This agent has been implicated in cutaneous, pulmonary, eye and disseminated infections. It has never been isolated from the nose or any nasal infection. We report here a rare case of nasal vestibular abscess due to N. dassonvillei in an adult diabetic patient. The bacterium was identified on the basis of morphological and biochemical characteristics, and confirmed by sequencing the 16S rRNA and hsp65 genes. The patient was successfully treated with clarithromycin and levofloxacin. Though N. dassonvillei infections may be rare, the study highlights that it may cause a wide spectrum of disease manifestations, and laboratories should take care to isolate and identify the easily treatable pathogen.
