Frontiers in Microbiology (Jan 2019)

Variation in Mutant Prevention Concentrations

  • Crystal Gianvecchio,
  • Natalie Ann Lozano,
  • Claire Henderson,
  • Pooneh Kalhori,
  • Austin Bullivant,
  • Alondra Valencia,
  • Lauren Su,
  • Gladys Bello,
  • Michele Wong,
  • Emoni Cook,
  • Lakhia Fuller,
  • Jerome B. Neal,
  • Pamela J. Yeh,
  • Pamela J. Yeh

DOI
https://doi.org/10.3389/fmicb.2019.00042
Journal volume & issue
Vol. 10

Abstract

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Objectives:Understanding how phenotypic traits vary has been a longstanding goal of evolutionary biologists. When examining antibiotic-resistance in bacteria, it is generally understood that the minimum inhibitory concentration (MIC) has minimal variation specific to each bacterial strain-antibiotic combination. However, there is a less studied resistance trait, the mutant prevention concentration (MPC), which measures the MIC of the most resistant sub-population. Whether and how MPC varies has been poorly understood. Here, we ask a simple, yet important question: How much does the MPC vary, within a single strain-antibiotic association? Using a Staphylococcus species and five antibiotics from five different antibiotic classes—ciprofloxacin, doxycycline, gentamicin, nitrofurantoin, and oxacillin—we examined the frequency of resistance for a wide range of concentrations per antibiotic, and measured the repeatability of the MPC, the lowest amount of antibiotic that would ensure no surviving cells in a 1010 population of bacteria.Results: We found a wide variation within the MPC and distributions that were rarely normal. When antibiotic resistance evolved, the distribution of the MPC changed, with all distributions becoming wider and some multi-modal.Conclusion: Unlike the MIC, there is high variability in the MPC for a given bacterial strain-antibiotic combination.

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