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A Reference Broth Microdilution Method for Dalbavancin In Vitro Susceptibility Testing of Bacteria that Grow Aerobically
Published on: September 9, 2015
In vitro antibiotic susceptibilities of Yersinia pestis determined by broth microdilution following CLSI methods
Henry S Heine1, Jeremy Hershfield2, Charles Marchand2
1Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, USA henry.heine@medicine.ufl.edu.
Abstract:
In vitro susceptibilities to 45 antibiotics were determined for 30 genetically and geographically diverse strains of Yersinia pestis by the broth microdilution method at two temperatures, 28°C and 35°C, following Clinical and Laboratory Standards Institute (CLSI) methods. The Y. pestis strains demonstrated susceptibility to aminoglycosides, quinolones, tetracyclines, β-lactams, cephalosporins, and carbapenems. Only a 1-well shift was observed for the majority of antibiotics between the two temperatures. Establishing and comparing antibiotic susceptibilities of a diverse but specific set of Y. pestis strains by standardized methods and establishing population ranges and MIC50 and MIC90 values provide reference information for assessing new antibiotic agents and also provide a baseline for use in monitoring any future emergence of resistance.
Insights
This study evaluated antibiotic susceptibility in diverse Yersinia pestis strains using standardized methods. Y. pestis showed broad susceptibility, with minimal changes in antibiotic effectiveness between 28°C and 35°C.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Yersinia pestis is the causative agent of plague, a re-emerging infectious disease.
- Understanding antibiotic susceptibility is crucial for effective plague treatment and control.
Purpose of the Study:
- To determine in vitro antibiotic susceptibilities for diverse Yersinia pestis strains.
- To establish baseline susceptibility data and population ranges for Y. pestis antibiotics.
- To assess the impact of temperature on Y. pestis antibiotic susceptibility.
Main Methods:
- Broth microdilution method used for 45 antibiotics against 30 Y. pestis strains.
- Testing conducted at two temperatures: 28°C and 35°C.
- Methods followed Clinical and Laboratory Standards Institute (CLSI) guidelines.
Main Results:
- Y. pestis strains were susceptible to aminoglycosides, quinolones, tetracyclines, β-lactams, cephalosporins, and carbapenems.
- A minimal (1-well) shift in susceptibility was observed between 28°C and 35°C for most antibiotics.
- Established MIC50 and MIC90 values for reference.
Conclusions:
- Yersinia pestis maintains broad in vitro antibiotic susceptibility across common drug classes.
- Temperature variations within a relevant range do not significantly alter Y. pestis antibiotic susceptibility.
- The generated data provide a vital reference for new antibiotic evaluation and monitoring future resistance emergence.
