Isolation of methicillin resistant staphylococcus aureus from the environmental samples in Dhaka City

Abstract

Methicillin resistant Staphylococcus aureus have emerged over more than 50 years ago. The indiscriminate use of antibiotics is responsible for its prevalence. This comparative study has been carried out to show the antibiotic/Methicillin sensitivity of Staphylococcus aureus collected from the environmental samples of different locations of Dhaka city. The bacterial isolates were identified depending on their structural, morphological and biochemical characteristics. Antibiogram according to Clinical and Laboratory Standards Institute (CLSI) guidelines, was done in order to perceive the antibiotic susceptibility of the isolates. Antibiogram revealing the sizes of zone of inhibition of the isolates showed that the environmental samples are not exposed to the methicillin resistant Staphylococcus aureus. This result indicates that since environmental Staphylococcus species are not exposed to antibiotics so they have not achieved resistivity against methicillin. Commercial antibiotic disks of Erythromycin (E), Tetracycline (TE), Oxacillin (OX), Clindamycin (DA) and Vancomycin (VA) were used in disk diffusion process to observe the antibiotic sensitivity. Antibiotics have different mode of actions such as cell wall synthesis inhibitors, membrane permeability alternatives, protein synthesis inhibitors and DNA synthesis inhibitors. The presence of the methicillin sensitive Staphylococcus aureus was further ensured from the PCR result. DNA extraction from the samples was done to isolate the DNA template required to carry out PCR. Specific primers mec A P4 and mec A P7 were used in to amplify the methicillin resistant gene and then the amplicons were run on agarose gel electrophoresis to observe the DNA bands. The result showed no bands when viewed under the UV light and thus this indicated the absence of methicillin resistant Staphylococcus aureus in the environmental samples. The study will help to predict the future emergence and guide to develop strategies to maintain the sensitivity preventing the antibiotic resistance among the organisms in the environment.