# MULTIPLE RESISTANCE TO ANTIBIOTICS

> **NIH NIH R01** · TUFTS UNIVERSITY BOSTON · 1994 · $256,850

## Abstract

Description (adapted from applicant's abstract):  Multiple antibiotic
resistance is becoming a more frequent observation in clinical isolates
throughout the world.  A chromosomal regulatory locus called mar in E.
coli  and other enterobacteriaceae confers resistance to a variety of
antibiotics  when overexpressed.  This kind of resistance has been found
in E. coli  clinical isolates from several countries.

The proposed studies are designed to purify and define functionally the
regulatory proteins of two divergent operons in the mar locus and to
determine  genes in the mar regulon that are targets of these proteins
and that produce  the Mar phenotype.  The marRAB operon encodes MarR, a
repressor of transcription, and MarA and MarB, putative activators of
distant loci.  Component genes will be cloned, purified as fusion
proteins and tested for  function.  Electrophoresis will assist in
identifying proteins involved in the  Mar system.  Potential DNA
sequences for the regulatory proteins will be  identified.  Undefined
resistance mechanisms for chloramphenicol, beta-lactam  antibiotics and
rifampicin will be studied.  The frequency of mar operon  mutations will
be examined, as will the possible existence of similar systems  in
Pseudomonas aeruginosa.  Homologous loci in other chromosomally resistant
organisms such as the mycobacteria will be sought.

## Key facts

- **NIH application ID:** 2190336
- **Project number:** 9R01GM051661-11A1
- **Recipient organization:** TUFTS UNIVERSITY BOSTON
- **SAM.gov UEI:** C1F5LNUF7W86
- **Principal Investigator:** STUART B. LEVY
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1994
- **Award amount:** $256,850
- **Award type:** 9
- **Project period:** 1980-09-30 → 1998-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/2190336

## Citation

> US National Institutes of Health, RePORTER application 2190336, MULTIPLE RESISTANCE TO ANTIBIOTICS (9R01GM051661-11A1). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/2190336. Licensed CC0.

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