Phenotypic and Genotypic Detection of Methecillin Resistance in Locally Isolated Staphylococcus aureus

A.Al-Oubaidy, Shaimaa

	Phenotypic and Genotypic Detection of Methecillin Resistance in Locally Isolated Staphylococcus aureus
Al-Mustansiriyah Journal of Science
Article 1, Volume 23, Issue 7, 2012, Pages 23-32
Author
Shaimaa A.Al-Oubaidy
Abstract
Total (150) isolates of Staphylococci species were isolated from different clinical samples. They were distributed as (41) isolates from urine, (59) isolates from wound infections and (50) isolates from ear swabs. These isolates were diagnosed using different morphological and biochemical test followed by the complementary api 20E test and mast staph kit. Out of 150 isolates, (58%) were Staphylococcus aureus. Results of primary screening test for methicillin resistance using disk diffusion method revealed that 84 isolates(96.5%) were proved to be methicillin resistant Staphylococcus aureus(MRSA). Twenty five isolates were selected for the genotypic study to detect methicillin resistance gene (mecA )using the polymerase chain reaction (PCR) . Two target sequences related to this gene were chosen in the current study ,the first represent the total gene segment (1339 bp) since the forward and the reverse primers were picked up from the upstream and the downstream region from the original gene while the other amplified segment represent part of the gene (314 bp ) . Total genomic DNA was used as a Template and it was prepared either by direct colony or by boiling method using distilled water or TE buffer. Results showed that all the selected 25 isolates (100%) were harboring mec A gene based on the presence of 314 bp or 1339bp clear bands in 1% agarose gel as compared with DNA ladder .Direct colony was better in preparing the template DNA compared with the boiling method which gave a negative results with the two amplified segments.

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