Variable Susceptibility to Gallium Compounds of Major Cystic Fibrosis Pathogens

ACS Infect Dis. 2022 Jan 14;8(1):78-85. doi: 10.1021/acsinfecdis.1c00409. Epub 2021 Dec 29.


The decreasing efficacy of existing antibiotics against pulmonary pathogens that affect cystic fibrosis (CF) patients calls for the development of novel antimicrobials. Iron uptake and metabolism are vital processes for bacteria, hence potential therapeutic targets. Gallium [Ga(III)] is a ferric iron-mimetic that inhibits bacterial growth by disrupting iron uptake and metabolism. In this work we evaluate the efficacy of three Ga(III) compounds, namely, Ga(NO3)3, (GaN), Ga(III)-maltolate (GaM), and Ga(III)-protoporphyrin IX (GaPPIX), against a collection of CF pathogens using both reference media and media mimicking biological fluids. All CF pathogens, except Streptococcus pneumoniae, were susceptible to at least one Ga(III) compound. Notably, Mycobacterium abscessus and Stenotrophomonas maltophilia were susceptible to all Ga(III) compounds. Achromobacter xylosoxidans, Burkholderia cepacia complex, and Pseudomonas aeruginosa were more susceptible to GaN and GaM, whereas Staphylococcus aureus and Haemophilus influenzae were more sensitive to GaPPIX. The results of this study support the development of Ga(III)-based therapy as a broad-spectrum strategy to treat CF lung infections.

Keywords: antimicrobial susceptibility testing; cystic fibrosis; gallium maltolate; gallium nitrate; gallium protoporphyrin IX.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cystic Fibrosis*
  • Gallium*
  • Humans
  • Microbial Sensitivity Tests
  • Pseudomonas aeruginosa
  • Stenotrophomonas maltophilia*


  • Gallium