Open AccessThe inoculum effect and band‐pass bacterial response to periodic antibiotic treatment
Author(s) -
Tan Cheemeng,
Phillip Smith Robert,
Srimani Jaydeep K,
Riccione Katherine A,
Prasada Sameer,
Kuehn Meta,
You Lingchong
Publication year - 2012
Publication title -
molecular systems biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 8.523
H-Index - 148
ISSN - 1744-4292
DOI - 10.1038/msb.2012.49
Subject(s) - library science , engine department , computer science , engineering , mechanical engineering
The inoculum effect (IE) refers to the decreasing efficacy of an antibiotic with increasing bacterial density. It represents a unique strategy of antibiotic tolerance and it can complicate design of effective antibiotic treatment of bacterial infections. To gain insight into this phenomenon, we have analyzed responses of a lab strain of Escherichia coli to antibiotics that target the ribosome. We show that the IE can be explained by bistable inhibition of bacterial growth. A critical requirement for this bistability is sufficiently fast degradation of ribosomes, which can result from antibiotic‐induced heat‐shock response. Furthermore, antibiotics that elicit the IE can lead to ‘band‐pass’ response of bacterial growth to periodic antibiotic treatment: the treatment efficacy drastically diminishes at intermediate frequencies of treatment. Our proposed mechanism for the IE may be generally applicable to other bacterial species treated with antibiotics targeting the ribosomes.