Plasmid Profile and Transformation Efficiency in Staphylococcus aureus isolated from different clinical specimens

Staphylococcus aureus a common cause of many diseases related to human health. It colonizes the skin and mucosal surfaces, and the most consistent site from which this bacterium can be cultured in the anterior nares. A total of 261 patients' samples taken were received from the different hospitals in Erbil city from July 2019 to January2020. Using various methods for suspected S. aureus identifications. The antimicrobial susceptibility test results against 16 antimicrobials showed variable susceptibility patterns. The transformation efficiency was calculated for ten more resist isolates of S. aureus. Based on morphological, cultural, and biochemical tests, 93 isolates of S. aureus were isolated and identified from 261 samples (35.63%). Likewise, in molecular identification, PCR was used based on the 16S rRNA and nuc genes, and all 93 isolates were reidentified. The antimicrobial susceptibility test results against 16 antimicrobials showed variable susceptibility patterns. The highest resistance was recorded against oxacillin 98.96%, and the lowest was 0% for each of amikacin, gentamicin, and trimethoprim-sulfamethoxazole. To determine the location of responsible genes for antibiotics resistance in S. aureus isolates, the genetic transformation process of laboratory Escherichia coliDH5 alpha strain with purified plasmid DNA from S. aureus isolates, was conducted successfully. Colonies of this process appear to be resistant to ampicillin, nalidixic acid, and penicillin, which indicates that the genes encoding these antibiotics resistance were located on plasmid DNA. The transformation efficiency was calculated for ten more resist isolates of S. aureus, and the results were ranged from more efficient (1.0185*10(4)) in SA59 isolate to the low efficiency of transformation (10.525*10(3)) for isolate SA69. On the other hand, the transformation frequency was revealed the various range and the transformation frequency for isolate SA59 was shown the highest frequency among all ten isolates (2.7*10(-4)). In contrast, the lowest frequency was 1.4*10(-5) for isolate SA69.