Malthusian Parameters as Estimators of the Fitness of Microbes: A Cautionary Tale about the Low Side of High Throughput.

• Type of Material: Article
• Authors: Jeniffer Concepcion-Acevedo, Emory University; Howard Weiss, Emory University; Waqas Chaudhry, Emory University; Bruce Levin, Emory University
• Language: English
• Date: 2015
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: This is an open access article, free of all copyright.
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0126915
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 10
• Issue: 6
• Start Page: e0126915
• End Page: e0126915
• Grant/Funding Information: The Bioscreen TM plate reader was purchased with funds from a grant from Procter and Gamble.; This research was supported by a grant from the US National Institutes of General Medical Science, GM098175 (BRL) and from the Higher Education Commission Pakistan (WNC).
• Research Categories: Biology, Microbiology

Abstract

The maximum exponential growth rate, the Malthusian parameter (MP), is commonly used as a measure of fitness in experimental studies of adaptive evolution and of the effects of antibiotic resistance and other genes on the fitness of planktonic microbes. Thanks to automated, multi-well optical density plate readers and computers, with little hands-on effort investigators can readily obtain hundreds of estimates of MPs in less than a day. Here we compare estimates of the relative fitness of antibiotic susceptible and resistant strains of E. coli, Pseudomonas aeruginosa and Staphylococcus aureus based on MP data obtained with automated multi-well plate readers with the results from pairwise competition experiments. This leads us to question the reliability of estimates of MP obtained with these high throughput devices and the utility of these estimates of the maximum growth rates to detect fitness differences.