Related Experiment Video
Updated: Aug 12, 2026
Using a Bacterial Pathogen to Probe for Cellular and Organismic-level Host Responses
Published on: February 22, 2019
In vitro susceptibility of Prototheca spp. to gentamicin
1Department of Microbiology and Immunology, West Virginia University School of Medicine, Morgantown 26506.
Abstract:
One hundred strains of Prototheca zopfii, Prototheca wickerhamii, Prototheca moriformis, Prototheca stagnora, and Prototheca ulmnea; five strains of Chlorella protothecoides; and two strains of Candida albicans were obtained from a number of different clinical and environmental sources and were tested for their in vitro susceptibility to the antibacterial agent gentamicin. All Prototheca strains were susceptible to gentamicin at concentrations between 0.3 and 0.9 micrograms/ml. A modified macrobroth dilution MIC assay with a colorimeter and a microbroth dilution assay with a 96-well plate reader were the two methods used to determine the MICs.
Insights
Gentamicin effectively inhibits the growth of Prototheca species, including Prototheca zopfii and Prototheca wickerhamii, at low concentrations. This study assessed the in vitro susceptibility of various Prototheca strains 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.
