The Effect of Silver and Zinc Oxide Nanoparticles on Multi Drug Resistance Staphylococcus aureus

Forty two isolates of Staphylococcus aureus were isolated from different clinical sources distributed among 24(57.2%) isolates from Urinary tract infection, 8(19.0%) isolates from wound and 10(23.8%) isolates from pus for the patients attending the laboratories of Rizgary Teaching Hospital and Rizhawa Hospital in Erbil City from March to September 2013.The isolates were diagnosed based on cultural characteristics, microscopical features and biochemical tests in addition to the API Staph. The study accomplished with sensitivity of isolates against (12) types of antibiotics. Eighty eight percentage of the isolates were resistant to Ampicillin (AM/10 µg), 81% resistant to Amoxicillin (AX/25 µg) while the lower resistance was registries against Nitrofurantoin (NIT/300 µg), Ciprofloxacillin (CIP/5 µg) and Gentamicin (GM/10 µg) 21.4%, 26%, 31% respectively. Ten isolates were selected according to their pattern of the highest resistance as these showing multi-drug resistances and tested to specify their minimum inhibitory concentration (MIC) for the antibiotics and two types of Nanoparticles include Silver in different sizes (20, 90)nm and Zinc Oxide in different sizes (20, 30, 50~150)nm. The results showed that the MIC for Ag20nm was between (650 -2600) µg/ml and Ag90nm was between (325 -2600) µg/ml while the MIC for Zn O20, 30, 50~150nm was between (325-2600) µg/ml for different sizes. Synergism effect between the antibiotics and the Nanoparticles when they integrate increased their effect of Staphylococcus aureus. The AMPc gene was founded in six isolates under study where extent in191bp but the blaCTX gene wasn't founded in this isolates where extent in 701 bp. Scanning electron microscopy (SEM) was used to study the biocide action of this Nanoparticles. The results confirmed that the treated Staph.aureus cells were damaged.