WASHINGTON, D.C. — Initiating aggressive therapy with appropriate antibiotics within 24 hours improved prognosis among patients with Staphylococcus aureus bloodstream infections, researchers reported here at ICAAC 2014.
“The take-home message is to treat patients aggressively if they have S. aureus infections,” Zhanni Weber, BScPharm, an MSc candidate at the faculty of pharmacy at the University of Manitoba in Winnipeg, Canada, told Infectious Disease News. “For patients with methicillin-sensitive S. aureus, this means targeting treatment with cloxacillin or cefazolin. Exposing patients as soon as possible to the best antibiotics, and maintaining that exposure without interruption, resulted in higher cure rates.”
Weber and Sheryl Zelenitsky, PharmD, professor in the faculty of pharmacy at the University of Manitoba, conducted a retrospective study that included 108 evaluable patients with laboratory-confirmed, clinically significant S. aureus bloodstream infections (BSIs) from 2009 to 2013. The analysis excluded cases that involved polymicrobial or relapsing bloodstream infections, dialysis or early mortality. They evaluated associations between early antibiotic therapy and clinical outcomes.
Among the 108 cases, 77.8% involved complicated S. aureus BSIs and 85.1% of the infections were methicillin-sensitive S. aureus (MSSA). The researchers focused on patients with complicated MSSA infections.
“There has been much focus on antibiotic treatment for MRSA, but MSSA has been understudied,” Weber said. “Patients with complicated infections would benefit most from antibiotic therapy so we focused on this group of patients.”
There were 71 complicated MSSA cases; 63.4% of these had a clinical cure at the end of treatment and 36.6% had treatment failure. Risk factors for treatment failure included advanced age, higher Charlson Comorbidity Index and health care–associated infections.
If appropriate antibiotics were initiated within 24 hours of a positive blood culture, and that appropriate exposure was maintained for the duration of therapy, the cure rate was significantly higher (72% vs. 48%, P = .024).
“Greater cure rate was also observed when these patients were exposed to at least 4 days of optimal targeted antibiotics, such as cloxacillin, nafcillin or cefazolin, within the first 7 days of positive blood culture,” Weber said.
Weber said that future research could evaluate the strategies in a pre-intervention and post-intervention study. — by Emily Shafer
Zhanni Weber, BScPharm, can be reached at: firstname.lastname@example.org.
For more information:
Weber Z. Abstract K-383. Presented at: Interscience Conference on Antimicrobial Agents and Chemotherapy; Sept. 5-9, 2014; Washington, D.C.
Disclosure: Weber reports no relevant financial disclosures.