Antibiotic-Selected Gene Amplification Heightens Metal Resistance

Area of Science:

• Microbiology
• Environmental Science
• Medical Science

Background:

• Antibiotic resistance is a growing threat in healthcare.
• Healthcare facilities use bactericidal metals to prevent pathogen colonization.
• The impact of antibiotic exposure on metal resistance in bacteria is largely unknown.

Purpose of the Study:

• To investigate if antibiotic exposure affects metal resistance in multidrug-resistant bacteria.
• To understand the interplay between antibiotic and metal resistance mechanisms.
• To assess the implications for bacterial transmission in healthcare settings.

Main Methods:

• Culturing a multidrug-resistant Enterobacter clinical isolate with colistin.
• Analyzing DNA amplification in colistin-resistant subpopulations.
• Assessing the function of the amplified genetic region for metal resistance using E. coli K-12.

Main Results:

• Colistin treatment selected for a 9-kb DNA duplication in Enterobacter cloacae.
• The amplified region contained the ncrABC locus, conferring nickel resistance.
• ncrABC expression alone conferred nickel resistance to E. coli K-12.
• Colistin exposure enhanced nickel resistance in the selected bacterial subpopulation.

Conclusions:

• Antibiotic use can inadvertently promote bacterial resistance to antimicrobial metals.
• This interplay has significant implications for bacterial colonization and transmission in healthcare environments.
• Further research is needed to understand and mitigate this phenomenon.