Читать книгу Microbial Interactions at Nanobiotechnology Interfaces - Группа авторов - Страница 35

The resistant mechanism involving target modification and protection has been also observed in various clinically resistant strains of bacteria. A typical example of target modification is found in methicillin‐resistant Staphylococcus aureus (MRSA) strains. In MRSA strains, the resistance mechanism to β‐lactams is conferred by the exogenous penicillin‐binding protein (PBP) called PBP2a. The acquired PBP2a is devoid of trans‐glycosylase activity; hence, it acts along with native PBP2 to confer the β‐lactams. PBP2a coded by mecA gene is located in large mobile genetic elements called staphylococcal chromosomal cassette (Fishovitz et al., 2014; Liu et al., 2016). Another example of target modification is vancomycin resistance in enterococci. The acquired vancomycin resistance genes called “van gene clusters” are located on the mobile genetic elements. Among the different types of van clusters, vanA and vanB are the most effective resistant systems as they are found in critical clinical strains (Miller, Munita, & Arias, 2014).