Efficacy of silver oxide nanoparticles against multi-drug resistant Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus in burn wound infections

Abstract

Multi-drug resistant (MDR) bacterial infections rapidly increase morbidity, mortality, and treatment options. Therefore, the search for, development of, or discovery of antimicrobial drugs capable of combating MDR bacteria is urgently needed. The potential of nanotechnology to advance nanomedicine for human health is being studied. The purpose of the present research is to investigate the antimicrobial activity of silver oxide nanoparticles against carbapenem-resistant Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus. For this purpose, a total of 240 pus and wound samples were collected from the burn patients and further processed for isolation and identification of P. aeruginosa and MRSA according to standard microbiological techniques. Using a species-specific primer for each bacterial strain, polymerase chain reaction was used for molecular detection. Antimicrobial susceptibility was performed according to the Kirby-Bauer Disk Diffusion method. Molecular detection of carbapenemase-producing P. aeruginosa was performed by PCR by using specific primers. The agar well diffusion assay was used to examine the antibacterial properties of silver oxide nanoparticles, and the broth dilution assay was used to estimate the minimum inhibitory concentration and bactericidal concentration respectively. Out of 240 samples, 42 (17%) were identified as P. aeruginosa and 32 were confirmed as S. aureus isolates. From positive isolates of P. aeruginosa, 25 (59%) were recorded MDR P. aeruginosa and from positive isolates of S. aureus, 18 (56.25%) were detected as MRSA. The highly resistant drug against S. aureus was Penicillin G (100%) followed by Gentamicin (84.37%) and Ciprofloxacin (81.25%). The highly resistant drug against P. aeruginosa was Meropenem (100%), Imipenem (100%) followed by piperacillin (71.42%), gentamicin (64.28%), and ciprofloxacin (64.28%). Out of 42 P. aeruginosa isolates, 8(19%) the prevalence of carbapenemase encoding was noted as blaOXA 3(37.5%), blaNDM 2(25%), blaVIM 1(12.5%) blaKPC 1(12.5%) and blaIMP 1(12.5%).  Silver oxide nanoparticles were considered an effective antibacterial agent with 0.0065mg/mL-0.026mg/mL concentrations that highly inhibited the growth of MRSA and 0.39mg/mL-1.56mg/mL concentrations inhibited the growth of P. aeruginosa. The statistical analysis showed that the MIC and MBC for MDR P. aeruginosa were 0.96±0.43 μg/mL and 1.99±0.90 μg/mL, respectively, while for MRSA they were 0.01±0.008 μg/mL and 0.04±0.012 μg/mL, respectively. The MBC values were higher than MIC values for both pathogens. Silver oxide nanoparticles have such effective antibacterial properties that they can be used as an adequate source of antibacterial agents as alternatives to antibiotics.