In vitro susceptibility of Prototheca spp. to gentamicin.

Area of Science:

• Microbiology
• Antimicrobial Susceptibility Testing
• Clinical Mycology

Background:

• Prototheca species are emerging opportunistic pathogens.
• These algae-like organisms can cause infections in humans and animals.
• Limited data exists on the antimicrobial susceptibility of Prototheca species.

Purpose of the Study:

• To determine the in vitro susceptibility of various Prototheca species to gentamicin.
• To establish minimum inhibitory concentrations (MICs) for gentamicin against Prototheca strains.
• To evaluate gentamicin as a potential therapeutic agent for Prototheca infections.

Main Methods:

• One hundred strains of Prototheca (P. zopfii, P. wickerhamii, P. moriformis, P. stagnora, P. ulmnea), five strains of Chlorella protothecoides, and two strains of Candida albicans were tested.
• In vitro susceptibility testing was performed using modified macrobroth dilution and microbroth dilution assays.
• Minimum inhibitory concentrations (MICs) were determined using a colorimeter and a 96-well plate reader.

Main Results:

• All tested Prototheca strains demonstrated susceptibility to gentamicin.
• Gentamicin MICs ranged from 0.3 to 0.9 micrograms/ml for all Prototheca strains.
• Chlorella protothecoides and Candida albicans strains were also tested for comparison (specific results not detailed in abstract).

Conclusions:

• Gentamicin is effective in vitro against a wide range of Prototheca species.
• The established MICs suggest gentamicin could be a viable treatment option for Prototheca infections.
• Further clinical studies are warranted to confirm the efficacy of gentamicin in treating human and animal Prototheca infections.