Merck Manual

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Brian J. Werth

, PharmD, University of Washington School of Pharmacy

Reviewed/Revised May 2022 | Modified Sep 2022

Carbapenems include

  • Ertapenem

  • Imipenem

  • Meropenem

Most Enterococcus faecalis Enterococcal Infections Enterococci are gram-positive, facultative anaerobic organisms. Enterococcus faecalis and E. faecium cause a variety of infections, including endocarditis, urinary tract infections... read more and many Pseudomonas aeruginosa Pseudomonas and Related Infections Pseudomonas aeruginosa and other members of this group of gram-negative bacilli are opportunistic pathogens that frequently cause hospital-acquired infections, particularly in ventilator... read more strains, including those resistant to broad-spectrum penicillins and cephalosporins, are susceptible to imipenem, meropenem, and doripenem but are resistant to ertapenem. However, meropenem and doripenem are less active against E. 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.

Imipenem and meropenem penetrate into cerebrospinal fluid when meninges are inflamed. Meropenem is used for gram-negative bacillary meningitis Acute Bacterial Meningitis Acute bacterial meningitis is rapidly progressive bacterial infection of the meninges and subarachnoid space. Findings typically include headache, fever, and nuchal rigidity. Diagnosis is by... read more ; 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.

The novel beta-lactamase inhibitors, avibactam, relebactam, and vaborbactam, can inhibit most carbapenemases but are ineffective against metallo-beta-lactamases (a type of carbapenemase that uses reactive zinc at the active site to destroy the carbapenem). The coformulation of avibactam with ceftazidime, vaborbactam with meropenem, or relebactam with imipenem increases activity against pathogens that produce serine carbapenemases. Examples of serine carbapenemases include Klebsiella pneumoniae carbapenemase (KPC) and OXA beta-lactamases.

Drugs Mentioned In This Article

Drug Name Select Trade
Ceptaz, Fortaz, Tazicef, Tazidime
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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