Antibacterial activity of silver nanoparticles against MDR Corynebacterium pseudotuberculosis isolated from caseous lymphadenitis cases.

Corynebacterium pseudotuberculosis (C. pseudotuberculosis) is a zoonotic pathogen with a poor treatment outcome. It causes a number of chronic disorders, such as caseous lymphadenitis (CLA) in sheep and goats. Also, it can spread to humans and cause potential health events. 120 samples from infected organs and abscessed lymph nodes of sheep and goats with caseous lymphadenitis pyogranulomas were isolated. 10 % (12) of samples were positive for C. pseudotuberculosis by phenotypic methods, pathogenicity testing of guinea pigs, and PCR for the 16 S rRNA. Then they were characterized for their antibiotic susceptibility. We studied the effect of silver nanoparticles (Ag-NPs) on a pan-drug-resistant strain of C. pseudotuberculosis that showed resistance to six classes of antibiotics. In this study, the minimum inhibitory concentration (MIC) was 0.1 mg/ml (100 ppm) and the minimum bactericidal concentration (MBC) of Ag-NPs were 0.05 mg/ml (50 ppm). In this study, the effects of Ag-NPs on the C. pseudotuberculosis morphology, indicated by scanning electron microscopy (SEM) at Matrouh Governorate, revealed pronounced morphological changes indicating damage and rupture of the bacterial membrane. In conclusion, Ag-NPs could be a promising treatment for caseous lymphadenitis pyogranulomas.