Synthetic lethality reveals mechanisms of Mycobacterium tuberculosis resistance to β-lactams

Shichun Lun, David Miranda, Andre Kubler, Haidan Guo, Mariama C. Maiga, Kathryn Winglee, Shaaretha Pelly, William Ramses Bishai

Research output: Contribution to journalArticle

Abstract

Most β-lactam antibiotics are ineffective against Mycobacterium tuberculosis due to the microbe’s innate resistance. The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains has prompted interest to repurpose this class of drugs. To identify the genetic determinants of innate β-lactam resistance, we carried out a synthetic lethality screen on a transposon mutant library for susceptibility to imipenem, a carbapenem β-lactam antibiotic. Mutations in 74 unique genes demonstrated synthetic lethality. The majority of mutations were in genes associated with cell wall biosynthesis. A second quantitative real-time PCR (qPCR)-based synthetic lethality screen of randomly selected mutants confirmed the role of cell wall biosynthesis in β-lactam resistance. The global transcriptional response of the bacterium to β-lactams was investigated, and changes in levels of expression of cell wall biosynthetic genes were identified. Finally, we validated these screens in vivo using the MT1616 transposon mutant, which lacks a functional acyl-transferase gene. Mice infected with the mutant responded to β-lactam treatment with a 100-fold decrease in bacillary lung burden over 4 weeks, while the numbers of organisms in the lungs of mice infected with wild-type bacilli proliferated. These findings reveal a road map of genes required for β-lactam resistance and validate synthetic lethality screening as a promising tool for repurposing existing classes of licensed, safe, well-characterized antimicrobials against tuberculosis.

IMPORTANCE: The global emergence of multidrug-resistant and extensively drug-resistant M. tuberculosis strains has threatened public health worldwide, yet the pipeline of new tuberculosis drugs under development remains limited. One strategy to cope with the urgent need for new antituberculosis agents is to repurpose existing, approved antibiotics. The carbapenem class of β-lactam antibiotics has been proposed as one such class of drugs. Our study identifies molecular determinants of innate resistance to β-lactam drugs in M. tuberculosis, and we demonstrate that functional loss of one of these genes enables successful treatment of M. tuberculosis with β-lactams in the mouse model.

Original languageEnglish (US)
Article numbere01767-14
JournalmBio
Volume5
Issue number5
DOIs
StatePublished - Sep 16 2014

Fingerprint

Lactams
Mycobacterium tuberculosis
Cell Wall
Genes
Carbapenems
Anti-Bacterial Agents
Pharmaceutical Preparations
Tuberculosis
Drug Repositioning
Extensively Drug-Resistant Tuberculosis
Synthetic Lethal Mutations
Lung
Mutation
Imipenem
Mycobacterium
Transferases
Bacillus
Real-Time Polymerase Chain Reaction
Public Health
Bacteria

ASJC Scopus subject areas

  • Microbiology
  • Virology
  • Medicine(all)

Cite this

Synthetic lethality reveals mechanisms of Mycobacterium tuberculosis resistance to β-lactams. / Lun, Shichun; Miranda, David; Kubler, Andre; Guo, Haidan; Maiga, Mariama C.; Winglee, Kathryn; Pelly, Shaaretha; Bishai, William Ramses.

In: mBio, Vol. 5, No. 5, e01767-14, 16.09.2014.

Research output: Contribution to journalArticle

Lun, S, Miranda, D, Kubler, A, Guo, H, Maiga, MC, Winglee, K, Pelly, S & Bishai, WR 2014, 'Synthetic lethality reveals mechanisms of Mycobacterium tuberculosis resistance to β-lactams', mBio, vol. 5, no. 5, e01767-14. https://doi.org/10.1128/mBio.01767-14
Lun, Shichun ; Miranda, David ; Kubler, Andre ; Guo, Haidan ; Maiga, Mariama C. ; Winglee, Kathryn ; Pelly, Shaaretha ; Bishai, William Ramses. / Synthetic lethality reveals mechanisms of Mycobacterium tuberculosis resistance to β-lactams. In: mBio. 2014 ; Vol. 5, No. 5.
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