Study Shows Importance of Antimicrobial Removal Systems in Blood Culture to Aid Diagnosis of Sepsis

A new study, published in the journal Clinical Infectious Diseases, demonstrates how treatment with broad-spectrum antibiotics can impact the ability to detect bacteria in blood samples from potentially septic patients. It also highlights the importance of antimicrobial removal systems in contemporary blood culture media to rapidly and accurately recover the organisms causing infection, to aid physicians in ultimately making treatment decisions for patients. The study was a head-to-head, prospective comparison of two aerobic blood culture media regularly used in the hospital setting to recover organisms that cause this serious and deadly blood infection.

Led by researchers at Hennepin County Medical Center, the study found that the BD BACTEC Plus Aerobic medium, a blood culture product from BD (Becton, Dickinson and Company), had faster time to detection and increased overall bacterial recovery from blood cultures where antimicrobials had been administered to the patient within the 48 hours before blood culture collection, as compared to another commonly used aerobic blood culture medium.

"Bloodstream infections, such as sepsis, are a serious and growing problem facing the medical community; they represent a leading cause of death both in the U.S. and worldwide, and significantly impact overall healthcare costs," says Tobi Karchmer, MD, worldwide vice president of medical affairs for BD Diagnostics - Diagnostic Systems. "This new study provides evidence that hospitals using sensitive and rapid blood culture media can make a difference in helping physicians, who are faced with making treatment decisions for severely ill patients, diagnose sepsis as quickly and accurately as possible to improve patient care and outcomes."

This independent, hospital-wide study represents the first clinical, head-to-head blood culture comparison study in 15 years. The study focused on the impact of prior antimicrobial exposure on bacterial recovery and time to detection using patient specimens, a key challenge facing critical care physicians and other healthcare professionals in addressing sepsis. The authors found that antibiotic administration prior to blood culture collection was common, with 51 percent of patients in the General Wards receiving antibiotics within four hours prior to blood culture specimen collection. In the medical intensive care unit (MICU), this figure jumped to 82 percent.

During the eight-month study period, a total of 9,395 blood cultures were collected and evaluated from adult patients admitted into the hospital's in-patient units and emergency departments, resulting in 1,219 (13 percent) positive cultures, of which 831 met the study inclusion criteria.1 Researchers concluded that the BD BACTEC Plus Aerobic medium had statistically significant higher recovery rates when antibiotics had been administered within four hours prior to specimen collection: 91 percent (216/237) of pathogens isolated and a faster time to detection an average of 4.4 hours faster as compared to recovery rates of another frequently used aerobic blood culture medium (41 percent or 98/237) evaluated in the study.1 Similar differences in recovery and time to detection in the presence of antibiotics were observed across all time points evaluated.

The study is published in the March 15, 2013 issue of Clinical Infectious Diseases.