الفهرس 
Introducing Staphylococcus aureusOnly 14 pages are availabe for public view
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Abstract
Methicillin resistance Staphylococcus aureus (MRSA) can cause a wide variety of clinical diseases. MRSA isolates were collected from health care workers (HCW), pus, blood, eyes, and urine of inpatients and outpatients of tertiary hospitals in Mansoura, Dakahlia. PCR was used to detect mecA, PVL, and SCCmecA. Antibiotic resistance, biofilm formation, β-lactamase production, and efflux pump were determined in all MRSA isolates. An aptosensor was developed using an aptamer that specifically binds PBP2a of MRSA and nanogold. Gold nanoparticles were prepared by the reduction of chloroauric acid using trisodium citrate.
Out of 320 clinical specimens of S. aureus, 103 (51.5%) were MRSA. MRSA prevalence in inpatients, outpatients, and healthcare workers was 43.5%, 46.0%, and 61.7%, respectively. The prevalence of MRSA in the blood, eye, urine, and puss samples was 50%, 46.67%, 35.71%, and 34.15%, respectively. MRSA isolates were tested for their SCCmecA types I-V. None of the MRSA isolates examined were SCCmecA type II. Type V MRSA strains were the most common (27.18%), followed by type IV strains (25.24%). The unidentified SCCmecA of MRSA isolates were 23.30%.
MRSA isolates were tested for their susceptibility to 15 tested antibiotics. The percentage of resistant strains to different antibiotic classes ranged between 4.85 (in the case of amikacin) and 100% (in the case of cefoxitin). All MRSA isolates were MDR to 4 to 13 antibiotics. β-lactamase production, efflux pump activity, biofilm formation, and PVL genes were detected in 94.2%, 45.63%, 49.51%, and 46.60% of the isolates, respectively.
An aptosensor was developed using a PBP2a-specific aptamer and nanogold particles of 10nm average size. The sensor produces a colour change from red to blue when it detects a MRSA isolate. The aptosensor has 100% specificity and sensitivity. Therefore, it is comparable to the PCR technique.The aptasensor has some critical advantages over the PCR method because it is cheaper, easier to perform, and does not need expensive equipment or specific molecular biology experience. Furthermore, it is very rapid.