Determination of In vitro Antimicrobial activity of copper on the clinical isolates of Acinetobacter spp

Abstract

Background: Acinetobacter spp., emerging pathogens equipped with the competence to establish multitudinous severe infections in immunocompromised hosts, are grievous threats to human health. To tackle the enormous burden of disease caused by Acinetobacter spp., the headlong discovery and the advancement of novel therapies are of the essence at this juncture. The present study attempted to determine the antimicrobial effects of copper on the clinical isolates of Acinetobacter spp. (Iso-03 and Iso-04). Methods: The potential deployment of copper-based antibacterial strategies against Acinetobacter spp. was assessed by exposing the isolates to the increasing concentrations of CuSO4 (from 2.5 to 1.5 mM) in liquid culture (M9 minimal medium) for 6 h and also through the exposure of them on solid metal surfaces (stainless steel and copper coupons) for 75 min, wherein the copper sensitivity and resistance of the clinical isolates of Acinetobacter spp. were determined. Results: There was no interference with the growth of the isolates at the low concentrations, whereas the bacterial growth was affected by the high concentrations of CuSO4 at different levels. During the exposure on the solid metal coupons, no loss of viability of isolates was observed on stainless steel, however, the rapid death of isolates was discernible on copper surface, leading to a dramatic decrease in the number of colony-forming units (CFUs), eventually to the limit of detection (3 CFUs per coupon). Conclusion: This study substantiated that copper possesses antimicrobial properties which can be deployed in novel therapies for the prevention of the infections caused by Acinetobacter spp. and other emerging pathogens. Further studies on the sensitivity and resistance of Acinetobacter spp. to copper at the molecular genetics levels can open the door to better exploitation of this metal for the inhibition of the vigorous growth of drug-resistant Acinetobacter spp.