Which agent is used to treat CRE (carbapenem-resistant Enterobacteriaceae) according to the material?

Prepare for the CAMLPR Microbiology Test. Utilize flashcards and engaging multiple-choice questions, each equipped with descriptions and explanations. Ready yourself for an excellent performance!

Infections with carbapenem-resistant Enterobacteriaceae are hard to treat because these bacteria often carry enzymes that inactivate many beta-lactam antibiotics. Colistin is described as an agent used against CRE because it targets the outer membrane of Gram-negative bacteria, binding to lipopolysaccharides and disrupting the membrane, which can kill these resistant organisms. It’s considered a last-resort option due to toxicity concerns, so it’s used with careful dosing and sometimes in combination with other drugs to improve outcomes. The other choices are less suitable in this context: ceftazidime is a cephalosporin that CRE commonly resist; tigecycline can be active against some CRE but has poor and variable serum levels, limiting its use for bloodstream infections; and saying never beta-lactams isn’t accurate since certain beta-lactam–inhibitor combinations may work against some CRE mechanisms, though not universally.