[Copper activity against multiresistant Gram negative bacilli isolated from Chilean hospitals]

Area of Science:

• Microbiology
• Infectious Diseases
• Environmental Health

Context:

• Nosocomial pathogens, particularly Gram-negative bacilli (GNB), pose a significant global public health threat.
• Copper alloys are explored for their antimicrobial properties to reduce bacterial load on hospital surfaces.
• Co-selection of antibiotic and copper resistance in GNB is a growing concern.

Purpose:

• To assess the antibacterial efficacy of copper against Gram-negative bacilli (GNB) with varying resistance profiles.
• Specifically evaluate copper's activity against nosocomial strains producing extended-spectrum beta-lactamases (ESBL) and those resistant or susceptible to carbapenems.

Summary:

• This study investigated 390 GNB strains from Chilean hospitals, including *Acinetobacter baumannii*, *Pseudomonas aeruginosa*, *Klebsiella pneumoniae*, and *Escherichia coli*.
• Strains were categorized by ESBL production and carbapenem resistance (CAR R/S). Copper susceptibility was determined using agar dilution.
• Results indicated significantly higher copper tolerance in carbapenem-resistant and ESBL-producing *A. baumannii* and *K. pneumoniae*.

Impact:

• A correlation was observed between reduced susceptibility to ionic copper and resistance to modern antimicrobial agents in *K. pneumoniae* and *A. baumannii*.
• Findings suggest that copper surfaces may not be universally effective against all nosocomial GNB, potentially driving co-selection for multidrug resistance.
• This highlights the need for careful consideration of copper's role in infection control strategies for multidrug-resistant organisms.