Carbapenems include
Imipenem
Carbapenems are parenteral bactericidal beta-lactam antibiotics that have an extremely broad spectrum. They are active against
Most Enterobacterales (including those that produce AmpC beta-lactamase and extended-spectrum beta-lactamase [ESBL], although Proteus mirabilis tends to have a higher imipenem minimum inhibitory concentration [MIC])
Methicillin-sensitive staphylococci and streptococci, including Streptococcus pneumoniae (except possibly strains with reduced penicillin sensitivity)
Most Enterococcus faecalis and many Pseudomonas aeruginosaE. faecalis than imipenem. Carbapenems are active synergistically with aminoglycosides against P. aeruginosa. However, E. faecium, Stenotrophomonas maltophilia, and methicillin-resistant staphylococci are resistant.
Many multidrug-resistant hospital-acquired bacteria are sensitive only to carbapenems.
meningitis; imipenem is not used in meningitis because it may cause seizures. Most seizures occur in patients who have central nervous system abnormalities or renal insufficiency and who are given inappropriately high doses.
Carbapenem resistance
Expanded use of carbapenems has resulted in some carbapenem resistance. This development is concerning because carbapenems are often the last resort for treating multidrug-resistant gram-negative organisms, particularly those that produce AmpC and extended-spectrum beta-lactamases, which destroy most beta-lactams except for carbapenems.
The most common mechanism of carbapenem resistance is
Carbapenemase production
However, carbapenem resistance may also be mediated by the loss or alteration of porin channels, the expression of efflux pumps, or penicillin-binding protein (PBP) modification.
Many carbapenemases are encoded on plasmids, facilitating the spread of resistance genes among organisms of the same species or even different bacterial species. If carbapenemase-producing pathogens are identified in a patient, infection control precautions and enhanced environmental cleaning should be instituted to prevent further transmission.
Klebsiella pneumoniae carbapenemase (KPC) and OXA beta-lactamases.
