Activity of Gallium Meso-and Protoporphyrin IX against Biofilms of Multidrug-Resistant Acinetobacter baumannii Isolates
Abstract
Acinetobacter baumannii is a challenging pathogen due to antimicrobial resistance and biofilm development. The role of iron in bacterial physiology has prompted the evaluation of iron-modulation as an antimicrobial strategy. The non-reducible iron analog gallium (III) nitrate, Ga(NO3)3, has been shown to inhibit A. baumannii planktonic growth; however, utilization of heme-iron by clinical isolates has been associated with development of tolerance. These observations prompted the evaluation of iron-heme sources on planktonic and biofilm growth, as well as antimicrobial activities of galliummeso- and protoporphyrin IX (Ga-MPIX and Ga-PPIX), metal heme derivatives against planktonic and biofilm bacteria of multidrug-resistant (MDR) clinical isolates of A. baumannii in vitro. Ga(NO3)3 was moderately effective at reducing planktonic bacteria (64 to 128 M) with little activity against biofilms (512 M). In contrast, Ga-MPIX and Ga-PPIX were highly active against planktonic bacteria (0.25 to8 M). Cytotoxic effects in human fibroblasts were observed following exposure to concentrations exceeding 128 M of Ga-MPIX and Ga-PPIX. We observed that the gallium metal heme conjugates were more active against planktonic and biofilm bacteria, possibly due to utilization of heme-iron as demonstrated by the enhanced effects on bacterial growth and biofilm formation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 17, 2016
- Accession Number
- AD1075691
Entities
People
- Carlos J. Sanchez
- Clinton K. Murray
- David Chang
- Joseph C Wenke
- Katrin Mende
- Kevin Skevin Akers
- Rebecca A. Garcia
Organizations
- United States Army Institute of Surgical Research