Extended-spectrum β-lactamases (ESBLs)

Definition

Extended-spectrum β-lactamases (ESBLs) are enzymes produced by certain bacteria that confer resistance to a wide range of β-lactam antibiotics, including penicillins and cephalosporins. These enzymes can hydrolyze the antibiotic, rendering it ineffective.

5 Must Know Facts For Your Next Test

1. ESBLs can be produced by both Gram-negative bacteria such as Escherichia coli and Klebsiella pneumoniae.
2. The presence of ESBLs is commonly detected using laboratory tests such as double-disk synergy tests or molecular methods like PCR.
3. Infections caused by ESBL-producing organisms often require treatment with carbapenems or other non-β-lactam antibiotics.
4. The spread of ESBL genes is facilitated through plasmid transfer between bacteria, promoting rapid dissemination.
5. Patients in healthcare settings, especially those with prolonged antibiotic use or invasive procedures, are at higher risk for infections by ESBL-producing bacteria.

Review Questions

• What types of antibiotics are rendered ineffective by the action of ESBLs?
• Which bacterial species are commonly associated with the production of ESBLs?
• What methods are used to detect the presence of ESBLs in bacterial isolates?

Related terms

β-lactam antibiotics: A class of broad-spectrum antibiotics that include penicillins, cephalosporins, monobactams, and carbapenems.

Carbapenem-resistant Enterobacteriaceae (CRE): A group of bacteria that have developed resistance to carbapenem antibiotics, often due to enzyme production.

Plasmid:

A small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently.