SAN FRANCISCO, CA 14 September 2012—For hospital patients whose blood harbors Enterobacteriaceae bacteria that produce extended-spectrum beta-lactamases (ESBLs), adequate antimicrobial therapy can mean the difference between life or death, a pharmacist-led research team reported Tuesday at the American Society for Microbiology's ICAAC.
Put into statistical terms, the chance of an inpatient surviving 30 days with ESBL-producing Enterobacteriaceae bacteremia decreases greatly—the hazard ratio is 3.7—if that person receives inadequate antimicrobial therapy.
The findings came from a 5.5-year review of data on 112 inpatients at three tertiary care teaching hospitals in Toronto, Canada.
University of Toronto's Norman Dewhurst said his team's findings highlight to health care practitioners four important points:
- Know your local antibiograms and antimicrobial resistance rates.
- Advocate hand hygiene by patients, health care providers, and the general public.
- Be judicious about your institutions' infection control practice; reassess overall antimicrobial prescribing patterns.
- Use antimicrobial stewardship interventions or other means to prevent the spread of multidrug-resistant bacteria.
Without prompt, appropriate antimicrobial therapy, hospital patients with ESBL-producing Enterobacteriaceae bacteremia face a losing battle. Of the 12 patients who received inadequate antimicrobial therapy, 58% were dead on day 7, the team discovered.
Bacteria that produce extended-spectrum beta-lactamases can resist the actions of penicillins, first-, second-, and third-generation cephalosporins, and aztreonam, according to one much-cited review article (PDF).
Yet, the use of an antimicrobial to which a bacterium appears susceptible does not guarantee a patient's survival. Dewhurst's team determined that 23% of the patients who received adequate antimicrobial therapy for their ESBL-producing Enterobacteriaceae bacteremia didn't survive 30 days.
The team considered an antimicrobial therapy "adequate" if test results showed that the ESBL-producing Enterobacteriaceae isolate was susceptible to at least one of the antimicrobials that had been ordered for the patient and that the patient received the microbe-susceptible antimicrobial for at least seven days or until death or discharge.
Escherichia coli isolates accounted for about 80% of the 112 cases.