Antibacterial efficacy of silver nanoparticles against metallo-β-lactamase (blaNDM, blaVIM, blaOXA) producing clinically isolated Pseudomonas aeruginosa.

Carbapenem resistance in Pseudomonas aeruginosa is a major concern in the public health sector, primarily in developing countries such as Pakistan. Therefore, novel approaches such as Silver nanoparticles (AgNPs) can be used to address emerging concerns. Clinical isolates (n=200) were reconfirmed using selective media and API 20NE kit. The antibiogram was determined according to the CLSI 2016 guidelines. Molecular detection was carried out by PCR. Antibacterial activity in AgNPs was achieved by dilution method. Of 200 P. aeruginosa, mostly (n=82; 41%) were isolated from pus samples. Of 110 MDR P. aeruginosa, 70 (63%) were carbapenemase and 58 (52%) were MBL producers. Antimicrobial profile of MBL producing P. aeruginosa reported that all isolates were resistant to β-lactams, and 89% to levofloxacin and ciprofloxacin except colistin. Of 25 (35.7%) blaNDM producing P. aeruginosa, 12 isolates (48%) had MIC 16μg/mL to imipenem. Of 23 (32%) blaVIM producing P. aeruginosa, 12 (52%) contained MIC 16μg/mL to imipenem. However, 12 (17.1%) blaOXA-48 producing P. aeruginosa, 4 (33%) contained MIC 16μg/mL to imipenem. In vitro AgNPs activity inhibited and killed MBL producing isolates at 1 mg/mL and 2 mg/mL, respectively. AgNPs may be used as an alternative therapy followed by multiple clinical trials.