Antimicrobial Resistance in Staphylococcus aureus

Abstract

Staphylococcus aureus is a Gram-Positive bacteria that are responsible to cause skin infections and also shows toxic shock syndrome. Several antibiotics were given against the S. aureus infections but eventually, the prevalence of multidrug resistance of Staphylococcus aureus started emerging. Since then Methicillin-resistant Staphylococcus aureus strains (MRSA)were very common which causes nosocomial infections. Microorganisms for the need of the survival undergoes mutational changes either in their chromosomal DNA/RNA which confers the resistance. One of the famous examples is the resistance against methicillin in Staphylococcus aureus. The evolution of S. aureus is successful in developing multiple resistant strains. Plasmids are capable of carrying the resistant genes and also several toxic genes. In a recent study, it has been observed that drug resistance genes are located in the R plasmids and they are also responsible in conferring multi drug resistance and induce less utilization of multiple antimicrobial therapy. MRSA was not only resistant to methicillin, studies proved MRSA strains were resistant to macrolides, tetracyclines, chloramphenicol. Resistance to vancomycin was very evidently observed, and its transfer among the population and rising of resistant strains was becoming a major threat globally. The resistance of all these antimicrobial agents against the pathogenic microorganisms are taking a rise in some patients due to prolong use of the antimicrobial agents by these patients. The multi drug resistance has enhanced the mortality and morbidity rate which referred to the infecting agents as the “Super Bugs”. Survival of the microorganisms has increased due to the gradual development of extensive resistance against varied antimicrobial drugs. Possible treatments with combinations are found to be the only hope for infections against S. aureus. Few drugs are in development such as Dalbavancin, Oritavancin, Tigecycline. These are the possible treatments upon which the work is going on to reduce the resistance against the invasive MRSA. This chapter highlights the profiles of Staphylococcus aureus and the resistance patterns along with transmission and the role of the plasmid in transmitting the resistance.