Antibacterial effect of silver nanoparticles and capsaicin against MDR-ESBL producing Escherichia coli: An in vitro study

ObjectiveTo evaluate the antibacterial property of silver nanoparticles (AgNPs) and capsaicin against multidrug resistant (MDR) and extended spectrum beta-lactamase (ESBL) producing Escherichia coli of bovine and poultry origin.MethodsAntibacterial efficacy of AgNPs and capsaicin was measured using broth dilution method. Five MDR-ESBL producing E. coli isolates of poultry (PEC4, PEC6, PEC15 and PEC16) and cattle mastitis origin (MEC2) were taken to evaluate the antibacterial effect of AgNPs and capsaicin.ResultsAt 50 mmol/L AgNPs, the viability of MDR of bacterial pathogens was reduced to almost 80%–90% and at 1000 mmol/L, the viability went down to 0%–3%. The minimum inhibitory concentration (MIC50) of AgNPs against these MDR-ESBL producing isolates was found to vary between 172–218 mmol/L whereas the MIC80 varied between 450–640 mmol/L. Capsaicin showed more prominent bactericidal effect and only at 2.5 mmol/L concentration, the viability was shown to be reduced by 20%–35% whereas at 7.5 mmol/L concentration, there was approximately 60% reduction in viability. Further at 25 mmol/L concentration, the viability was reduced to 0%–8%. The MIC50 and MIC80 of capsaicin against these MDR-ESBL producing isolates were found to vary between 4.6–7.5 mmol/L and 10.9–16.9 mmol/L, respectively.ConclusionsThe results point out that capsaicin and AgNPs could be of use in treating ESBL infection.