Assessment of Virulence Potential in Rhizopus species in Larvae of Galleria Mellonella and Mice

Somayeh Dolatabadi; Mohammad Javad Najafzadeh

doi:10.18502/ssu.v29i6.6997

Somayeh Dolatabadi Department of Biology, Faculty of Basic Sciences, Hakim Sabzevari University, Sabzevar, Iran.
Mohammad Javad Najafzadeh Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.

DOI: https://doi.org/10.18502/ssu.v29i6.6997

Keywords: Rhizopus, virulence, Galleria mellonella, mice model.

Abstract

Introduction: Although, Rhizopus species, are the main causative agents of mucormycosis, we know a little about these pathogens. We investigated the virulence potential of Rhizopus arrhizus and R. microsporus strains, obtained from a wide selection of clinical and environmental sources, in Galleria mellonella larvae and a mice model.

Methods: In this experiment, a total of 26 strains, 13 for each species of R. microsporus, R. arrhizus were tested in larvae with final concentration of 10⁶/ml per strain. Eight strains were tested in mice model. Inoculated samples were monitored in insect larvae for 6 days and in mice for 14 days. Statistical data were performed using Graphpad Prism software (GraphPad Software, San Diego, CA). Survival data of the samples were plotted using Kaplen-Meyer diagrams and analyzed using log rank test P value was considered 0.05%.

Results: R. arrhizus showed higher virulence compare to R. microsporus in both models. No specific difference was seen in pathogenicity between the two varieties of R. arrhizus. Virulence was not affected by source of isolation or production of toxin in some strains of R. microsporus. Virulence pattern was similar in both models.

Conclusion: Considering the mortality rate which was happened with strains from environmental sources, we conclude that these fungi have an opportunistic nature, which make them pathogen in susceptible hosts in favorite conditions. Larvae model showed reliable results compare to mice model.