RESUMO
Central venous catheter-related bloodstream infection [CR-BSI] remains a main source for septic morbidity and occurs in 4-14% of all catheters. Besides, its diagnosis lacks accuracy. We aimed to determine the diagnostic performance of the Gram stain Acridine Orange Leukocyte Cytospin [AOLC] test for the diagnosis of CR-BSI in ICU patients as compared to the routine semi-quantitative catheter culture method performed in our laboratory. A total of 50 intensive care unit patients with CVC having clinical suspicion of CR-BSI were enrolled in this study. The first two milliliters blood, were aspirated from the catheter before being removed and the Gram stain-AOLC test was done. About the same time, five to eight milliliters blood were collected from a peripheral vein, under aseptic conditions, inoculated onto a blood culture medium and sent to the microbiology laboratory for blood culture. Catheters were removed aseptically the tip was cut and sent to the microbiology laboratory for culture by a semi-quantitative technique. Catheter culture [CC] was positive in 46/50 [92%] of patients. Yet, only 23/46 patients [50%] met the criteria for diagnosis of CR-BSI. The sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and diagnostic accuracy [DA] for catheter culture were 100%, 15%, 50%, 100% and 54%, respectively. The AOLC test was positive in 32/50 patients [64%]. Twenty two out of the 32 [68.75%] positive cases had microbiologically confirmed CR-BSI. The AOLC test had 96% sensitivity, 63% specificity, 69% PPV, 94%NPV and 78% DA. The addition of the Gram-stain to the AOLC test was found to be positive in 18/50 patients [36%]. In patients with microbiologically confirmed CR-BSI, the Gram Stain-AOLC test was positive in 14/23 patients [60.8%]. The Gram-stain AOLC test had 61% sensitivity, 85% specificity, 78% PPV, 72% NPV and 74% DA. While, catheter culture by the semi-quantitative technique is more sensitive than the Gram-stain AOLC test in diagnosing CR-BSI, the Gram-stain AOLC test was found to be simple, rapid and specific and does not required the catheter removal. Thus can be used as a first line investigation for the diagnosis of CR-BSI, on which the decision to remove or replace a suspected CVC can be safely and accurately made