Improved recovery of microorganisms from patients receiving antibiotics with the antimicrobial removal device

Three hundred thirty-seven paired sets of blood cultures and ten sets of body fluid cultures from patients receiving antimicrobials were processed simultaneously by conventional methods with and without the use of an antimicrobial removal device (ARD) over a 13-month period of time in order to compare recovery rates. Forty-two significant pathogens were recovered: 19 by ARD processing only, four by conventional testing only, and the remaining 19 by both methods of processing. (P less than 0.001). Seventeen patient samples contained antimicrobics not active against the blood isolate (mainly Candida albicans). There was no difference (P greater than 0.1) between ARD-assisted and conventional methods in rate (frequency of cultures that were ultimately positive) or rapidity of detection of these microorganisms. In 17 subjects receiving antimicrobials active, in vitro, against the isolated microorganism, use of the ARD displayed a superior rate of recovery compared with conventional processing (P less than 0.001) and more rapidly detected organisms found both with and without ARD processing (P less than 0.04). Contamination rate was 3.7% for use of ARD compared with 0.6% without ARD (P less than 0.01). The ARD is a useful addition to conventional blood culture processing when used in a population of patients already receiving antimicrobial agents.