New Molecular Resistance Mechanisms against Antibiotics in Bacteria

Only a short time after the discovery of antibiotics by Alexander Fleming, antibiotic-resistant bacteria were reported. Besides the traditional mechanisms of resistance in bacteria, new mechanisms have been described by different researchers. For example, recently a new gene operon of D-alanine-D-serine called VanL that cuased resistant to the antibiotic vancomycin was reported. Other researchers have shown that Klebsiella pneumoniae strains lost purine Ompk36 that have a major role in the antibiotic diffusion into cells, are resistant to carbapenem. In 2011, the first full resistance to tigecycline was reported that the enzyme-linked monooxygenase flavin hydroxyl TetX cause deactivation of antibiotics. In 2012, high resistance to mupricin antibiotic was described that intermediated by a new locus named mupB. In addition, in 2013, it was showed that some strains of Enterococcus faecalis can move daptomycin antibiotic from its target to other places and so inhibit its activity. Removal of whole target gene (PBP3) of ceftazidime in Burkholderia pseudomallei was reported in 2012. In other hand, new role of riboswitch for resistance to aminoglycoside antibiotics reported in 2013. In addition, recent studies have indicated a relationship between SOS response and quorum sensing with antibiotic resistance and new antibiotic resistance mechanisms in bacterial biofilm and persister cells are known. In this review, recent studies have been conducted to identify these new mechanisms.