All of the following statements about Penicillin resistance are true, Except -: (A) beta-Lactamase production is the most common mechanism of resistance, (B) Alteration in target PBPs is an impoant resistance mechanism in gram negative bacteria, (C) Alteration in permeability/penetration of antibiotic causes resistance only in gram negative bacteria, (D) beta-Lactamase production causes resistance in both gram positive and gram negative bacteria
Answer is B. Ans. is b i.e., Alteration in target PBPs is an impoant resistance mechanism in gram negative bacteria PENICILLIN RESISTANCE o Mechanism of resistance are ? Penetration into the cell o Gram negative bacteria have an outer membrane just outside the cell wall. o Outer membrane is not present in gram positive bacteria, so this mechanism of resistance is not for gram positive organisms. beta-lactamase (Penicillinase) Production o This is the most common mechanism o Both gram positive and gram negative organism produce beta-lactamase which open the beta-lactam ring and inactivate the antibiotic. Altered penicillin bindinE protein (PBP) o Bacteria can alter the structure of penicillin binding protein, which is not other than transpeptidase. o So, penicillin can not bind to the site where it acts. o MRSA defends itself in this way. o Organism resistant to methicillin, MRSA is resistant to all other beta-lactam antibiotics.