Clinical Consideration of Coagulase Negative <i>Staphylococci </i>Isolated in Blood Culture

Abstract

Despite blood culture's usefulness in antimicrobial therapy, fewer blood cultures and the infrequency of more than 1 set in cultures appear to be problems in Japan. Since June 2007 infection control team (ICT) recommended more than 1 set in blood sampling and intervention in positive blood culture, coagulase negative Staphylococci (CNS) has frequently been isolated from blood culture and its clinical significance is often difficult to judge. To determine the effect of ICT intervention, we evaluated the number of blood culture specimens, the frequency of more than 1 set in all blood culture specimens, and decision-making on antimicrobial treatment for CNS isolated retrospectively from blood. The study was divided into term I in August 2007 to July 2008, term II in August 2008 to July 2009, and term III in August 2009 to February 2010. We also analyzed how physicians treated infection or its suspicion after CNS and its drug susceptibility. The monthly number of blood culture specimens increased from 40.3 to 51.6 between terms I and III. The frequency of more than 1 set in a single blood culture session rose significantly from 67% to 89% between these terms (p < 0.001). The number of indeterminate also dropped cases significantly during these 2 terms from 27% to 6% (p = 0.017). Infection or suspected infection cases--45 of 49--had central vein catheter implantation. Inappropriate treatment by physicians in these cases also dropped significantly from 85% (11/13) to 45% (5/11) (p = 0.043) during the same 2 terms. ICT Intervention may thus increase the number of blood culture specimens, enable more than 1 set in blood sampling, make it easier to judge the presence of infection, and increase appropriate treatment by physicians. We thus believe that the quality of antimicrobial treatment could be improved through education such as ICT action.