Increased detection of staphylococcal bacteremia using an anti-microbial removal device

During the period of August 16, 1981, through December 16, 1982, 15-mL blood culture specimens collected at the Seattle Veterans Administration Medical Center (SVAMC) were divided into two aliquots. The first 10-mL aliquot was inoculated directly into aerobic and anaerobic BACTEC (Johnston Laboratories, Towson, MD) vials (DIR); the remaining 5 mL was processed in an resin-containing Antimicrobial Removal Device (Marion Scientific, Kansas City, MO) before transfer to a second, identical set of aerobic and anaerobic vials (ARD). The final volume of inoculated blood from the ARD specimen was half that of the DIR specimen. Both sets of vials were processed using the BACTEC radiometric detection system. One hundred fifty specimen pairs grew 161 significant pathogens; 43 isolates were recovered only from the ARD sample, 39 only from the DIR samples, and 79 from both. Of the 35 isolates recovered from patients receiving anti-microbial agents active against the isolated pathogens, 21 were recovered only from the ARD specimen and 5 only from the DIR specimen (P less than 0.005). Of the 15 S. aureus strains isolated from patients on therapy, 12 were recovered only from the ARD specimen, 2 only from the DIR sample, and 1 from both samples (P less than 0.01). Ten of the 32 isolates of S. aureus recovered from antibiotic-free patients were found only in the ARD specimen and three only in the DIR specimen (P = 0.05). The ARD specimens recovered significantly more S. aureus from all patients regardless of antibiotic status.