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β-Lactam antibiotics are indicated for the prevention and treatment of bacterial infections caused by susceptible organisms. At first, β-lactam antibiotics were mainly active only against gram-positive bacteria, yet the recent development of broad-spectrum β-lactam antibiotics active against various gram-negative organisms has increased their usefulness.
Since the discovery of the beta-lactam antibiotic penicillin, the rates of antimicrobial resistance have increased. [38] Over time, methods for testing the sensitivity of bacteria to antibiotics have developed and changed. [25] Alexander Fleming in the 1920s developed the first method of susceptibility testing.
The β-lactam core structures. (A) A penam.(B) A carbapenam.(C) An oxapenam.(D) A penem.(E) A carbapenem.(F) A monobactam.(G) A cephem.(H) A carbacephem.(I) An oxacephem. This is a list of common β-lactam antibiotics—both administered drugs and those not in clinical use—organized by structural class.
There is a much lower risk of cross-sensitivity between aztreonam and other beta-lactam antibiotics than within other beta-lactam antibiotics. However, there is a higher chance of cross-sensitivity if a person is specifically allergic to ceftazidime, a cephalosporin. Aztreonam exhibits cross-sensitivity with ceftazidime due to a similar side chain.
A lactam is a cyclic amide, and beta-lactams are named so because the nitrogen atom is attached to the β-carbon atom relative to the carbonyl. The simplest β-lactam possible is 2-azetidinone. β-lactams are significant structural units of medicines as manifested in many β-lactam antibiotics. [2]
Beta-lactam ring in red. Escherichia coli bacteria on the right are sensitive to two beta-lactam antibiotics, and do not grow in the semi-circular regions surrounding antibiotics. E. coli bacteria on the left are resistant to beta-lactam antibiotics, and grow next to one antibiotic (bottom) and are less inhibited by another antibiotic (top).
Beta lactam resistance in these pathogens is most commonly due to the expression of beta lactamase enzymes. [ 34 ] Between 2007 and 2011, the percentage of Escherichia coli isolates from Canadian hospitals that produce extended spectrum beta lactamases (ESBL) increased from 3.4% to 4.1%; among Klebsiella pneumoniae isolates ESBL producers ...
MRSA is any strain of S. aureus that has developed (through natural selection) or acquired (through horizontal gene transfer) a multiple drug resistance to beta-lactam antibiotics. Beta-lactam (β-lactam) antibiotics are a broad-spectrum group that include some penams (penicillin derivatives such as methicillin and oxacillin) and cephems such ...