A Comparative study of the effect of zinc oxide and silver nanoparticles against antibiotic-resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic Gram-negative bacterium that causes serious infections in immunocompromised patients and is known for its high capacity to develop resistance to multiple antibiotics, making infections difficult to treat. The study aimed to investigate the prevalence of multiple antibiotic-resistant Pseudomonas aeruginosa species that cause many diseases, and to estimate the impact of nanoparticles on them and their use as alternatives or adjuncts to antibiotic treatment. A total of 182 clinical samples were collected, including urinary tract infections, wound swabs, pus, burns, and tonsillitis, from patients arriving at Al-Kindi Hospital in Baghdad between March to September 2024. Twenty-nine strains of Pseudomonas aeruginosa (16%) were identified based on morphological and cultural characteristics, biochemical tests, and the APi20E test. These strains were tested for their sensitivity to 10 types of antibiotics. The species showed high resistance to Ampicillin and Amoxicillin (100%), and the least resistance to Ciprofloxacin (35%). Nine strains with high resistance to antibiotics were selected, and the minimum inhibitory concentration (MIC) was determined against the antibiotics under study. In addition, some nanoparticles of different sizes (Ag20, 90nm, ZnO20, 30, 50~150, nm. The results showed that the MIC for Ag20, 90nm was 650-2600 µg/ml, while for ZnO20nm, the MIC values ranged between 81.25 -2600 µg/ml, while the MIC for ZnO30, 50~150nm was between 325- 2600 (µg/ml). The synergistic effect between antibiotics and nanomaterials showed high effectiveness in inhibiting the growth of Pseudomonas aeruginosa.