Predictors of catheter-related gram-negative bacilli bacteraemia among cancer patients

Gram-negative bacillary bacteraemia (GNB) is associated with high morbidity and mortality among cancer patients. We conducted this study to determine the risk factors that may predict the catheter as the source of GNB in cancer patients. From July 2005 to December 2006 all 266 cancer patients with GNB and central venous catheters (CVCs) at The University of Texas M. D. Anderson Cancer Centre in Houston, were classified as catheter-related bloodstream infection (CRBSI) according to Infectious Diseases Society of America criteria. We compared clinical and microbiological features of CRBSIs and non-CRBSIs. We identified 78 CRBSIs and 126 non-CRBSIs. On univariate analysis, polymicrobial bacteraemia, Stenotrophomonas maltophilia bacteraemia, and more than 1000 CFUs in CVC blood cultures, were more common among CRBSI cases. Escherichia coli bacteraemia, haematologic cancer, neutropenia and prior antibiotic use were more common among non-CRBSI cases. On multivariate analysis, S. maltophilia bacteraemia (odds ratio (OR), 5.78; 95% confidence interval (CI), 1.47-22.78; p 0.045), polymicrobial bacteraemia (OR, 4.04; 95% CI, 1.56-10.44; p 0.042), and more than 1000 CFUs from CVC blood cultures (OR, 4.39; 95% CI, 2.02-9.27; p <0.01), were associated with CRBSI. Neutropenia was associated with non-CRBSI (OR, 0.26; 95% CI, 0.13-0.53; p <0.01). Several factors such as S. maltophilia bacteraemia, polymicrobial bacteraemia and more than 1000 CFUs from a blood culture drawn through the CVC may assist the clinicians in assessing whether an indwelling catheter is the source of a GNB and hence CVC removal may be considered.