Pfaller and Segreti listed risk factors that can be used to identify a patient who may be harboring bacteria producing an extended-spectrum beta lactamase. A patient with one or more risk factors would be a candidate for closer monitoring and more aggressive management, especially if there was an unexplained failure in therapy with a beta-lactam antibiotic. The authors are from the University of Iowa in Iowa City and Rush Medical College in Chicago.

Antibiotic exposure-related risk factors:

(1) therapy with a third-generation cephalosporin

(2) therapy with trimethoprim-sulfamethoxazole

(3) therapy with ciprofloxacin

(4) total antibiotic exposure high

(5) delay in appropriate antibiotic therapy (failure to treat or inappropriate therapy)


Facility-related risk factors:

(1) prolonged hospital stay

(2) residence in a long-term care facility

(3) prolonged stay in an intensive care unit (adult or neonatal)


Condition-related risk factors:

(1) decubitus ulcer

(2) total dependence in activities of daily living

(3) severe illness


Management-related risk factors:

(1) indwelling catheter

(2) nasogastric or gastrostomy tube

(3) tracheostomy or endotracheal tube



• All 3 items in condition-related reflect need for prolonged hospitalization or care.


An additional item not given in the original reference is a high rate of extended spectrum beta-lactamase in the environment.

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