What are Carbapenem Resistant Enterobacteriaceae (CRE)? 

Carbapenem–resistant Enterobacteriaceae are bacteria that are resistant to the carbapenem group of antibiotics (i.e. ertapenem, imipenem, meropenem and doripenem). These Gram-negative bacteria are usually from the genera called Klebsiella, Enterobacter, Citrobacter, Salmonella, Escherichia, Shigella, Proteus and Serratia. Other bacteria can also become resistant to carbapenems, for example, Acinetobacter and Pseudomonas. Bacteria are highly adaptive organisms. Carbapenem antibiotics are broad-spectrum beta-lactam-type antibiotics that are especially effective against Gram-negative bacteria.

Carbapenem antibiotics were introduced in the early 1980s and were considered the last line of defense against Gram-negative bacteria that had become resistant to many other antibiotics. Over time, these Gram-negative bacteria developed resistance to the carbapenem antibiotics by preventing antibiotic entry (by the reduction of transmembrane channels), by transporting the antibiotic out of the bacterial cell (by upregulating specific efflux pumps to pump the antibiotic out of the bacterial cell), or by breaking down the carbapenems with an enzyme (carbapenemases). Refer to Carbapenemase Producing Enterobacteriaceae (CPE). In this way, carbapenem antibiotics can no longer kill these bacteria. The problem is that now the treatment of infections with these Gram-negative bacteria is extremely challenging.