BETHESDA, MD. — Patients infected with extended-spectrum β-lactamase-producing organisms did not have significantly lower mortality if treated with a carbapenem antibiotic, compared with untreated patients (25.8% vs. 26.1%), reported Jeremias L. Murillo, M.D., at an annual conference on antimicrobial resistance sponsored by the National Foundation for Infectious Diseases.
The retrospective study included 91 patients. They ranged in age from 13 to 99 years, with a mean age of 66 years; 45 patients were males and 46 were females.
Extended-spectrum β-lactamase (ESBL)-producing organisms are increasingly recognized as health care-associated pathogens, on par with vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA), said Dr. Murillo of the infection control department at the Newark (N.J.) Beth Israel Medical Center.
The objective of this study was to determine whether there were differences in mortality rate and length of hospital stay between patients who were treated with a carbapenem and those who were not, and whether mortality and length of stay differed among patients infected with different organisms, he said.
Escherichia coli, the most common cause of infection, was found in 45 patients, while Klebsiella pneumoniae infection occurred in 40 patients, and Klebsiella oxytoca was found in 6 patients.
The mortality rates for patients infected with these three organisms were 20.0%, 22.5%, and 16.6%, respectively.
Patients infected with Klebsiella pneumoniae spent significantly more time in the hospital, compared with the overall average length of stay for infected patients (75 days vs. 54 days).
Eight of 31 patients (25.8%) who received a carbapenem and 11 of 42 patients (26.1%) who did not receive a carbapenem died.
Acute Physiology and Chronic Health Evaluation (APACHE) II scores proved to be an accurate predictor of mortality; patients who died had significantly worse APACHE II scores at the time of positive culture, compared with patients who survived.
“This review was prompted by two observations. The first was the introduction of ESBL-producing organisms into our institution—a 600-bed inner-city tertiary care center—in 2002, and the second observation is the fact that there were some patients infected with ESBL-producing organisms who did fairly well in the absence of carbapenem treatment,” Dr. Murillo explained.