Extended spectrum Beta-Lactamase (ESBL) Organisms



Extended spectrum Beta-Lactamase (ESBL) Organisms


What are Extended Spectrum Beta-Lactamase Organisms?


Extended Spectrum Beta-Lactamase (ESBL) Organisms are bacterial strains which are able to produce an enzyme capable of cleaving the beta-lactam rings of some antibiotics. This beta-lactamase enzyme producing property of the bacteria renders the antibiotic ineffective.


Why is this of concern?


If an infection is not responsive to a certain antibiotic, bacterial swabs will be taken and cultured. The bacterial culture tests will determine if the infectious strain is in fact non-responsive to the current course of antibiotic treatment due to its Beta-Lactamase properties. The bacterial infection will then be treated with an antibiotic the bacteria is sensitive to.


How are Extended Spectrum Beta-Lactamase Organisms transmitted?


  • Person-person contact with infected individuals

  • Person-contaminated surface contact

  • coming in contact with infected bodily fluids


How is transmission prevented?

  • Isolation of the infected individual

  • Designating personal care items such as commodes, creams, washbasins to each patient

  • All visitors and Nursing staff adhering to isolation protocols of wearing gloves and mask when in contact with the patient

  • Using proper handwashing teachniques


Toronto East General Hospital. 2009. Extended spectrum Beta-Lactamase (ESBL) Organisms. Retrived June 1, 2009 from http://www.tegh.on.ca/bins/content_page.asp?cid=3-20-102.


Micobiological History of Beta-Lactamase Bacterial strains

Source:Bradford, Patricia, A. 2001. Extended-Spectrum Beta-Lactamases in the 21st Century: Characterization, Epidemiology, and Detection of This Important Resistance Threat. Clinical Microbiological Reviews. 14: (4) 933-951.

“Emergence of resistance to Beta-lactam antibiotics began even before the first Beta-lactam, penicillin, was developed. The first Beta- lactamase was identified in Escherichia coli prior to the release of penicillin for use in medical practice . The age of penicillin saw the rapid emergence of resistance in Staphylococcus aureus due to a plasmid-encoded penicillinase. This Beta-lactamase quickly spread to most clinical isolates of S. aureus as well as other species of staphylococci.

Many genera of gram-negative bacteria possess a naturally occurring, chromosomally mediated Beta-lactamase. These enzymes are thought to have evolved from penicillin-binding proteins, with which they show some sequence homology. This development was likely due to the selective pressure exerted by Beta-lactam-producing soil organisms found in the environment

Over the last 20 years, many new -lactam antibiotics have been developed that were specifically designed to be resistant to the hydrolytic action of Beta-lactamases. However, with each new class that has been used to treat patients, new Beta-lactamases emerged that caused resistance to that class of drug. Presumably, the selective pressure of the use and overuse of new antibiotics in the treatment of patients has selected for new variants of Beta-lactamase. One of these new classes was the oxyimino-cephalosporins, which became widely used for the treatment of serious infections due to gram-negative bacteria in the 1980s.”






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