Review: Methicillin and Vancomycin Resistant Staphylococcus Aureus

Abstract

Staphylococcus aureus is a Gram-positive bacterium that considered as an opportunistic pathogen responsible for great morbidity and mortality; human beings are its main reservoir. The organism is toxigenic and one of the effects of the toxin is reducing the efficacy of antibiotics. Before the discovery of antibiotics, mortality rate of S. aureus strains was more than 75 %. The over use as well as misuse of antibiotics in humans, nutritive and therapeutic antibiotic treatment of farm animals resulted in antibiotic-resistant bacteria. The first drug used to treat S. aureus was penicillin for which the bacteria becomes resistant in short time and oxacillin or methicillin was introduced as a drug of choice, but, the bacteria also became resistant to this drug. Methicillin resistant S. aureus has hospital-acquired and community-acquired phenotypes. Currently, vancomycin has been accepted worldwide as the last choice against methicillin resistant S. aureus infections and it’s widely usage resulted in vancomycin resistant strains and also multi drug resistant S. aureus. Its main mode of transmission is by direct contact with colonized or infected individuals and objects or surfaces contaminated. Constitutional symptoms of the disease are unusual. Diagnosis of S. aureus infection is carried out by culturing organisms from a focal site of infection followed by drug sensitivity test by disc diffusion method. Multiplex PCR method also used to detect resistant genes. Preventing the emergence of multidrug resistant organism require a systematic and comprehensive approach that build up the health care and public health system.

Keywords: Staphylococcus aureus, Methicillin, Vancomycin, Resistance