ORIGINAL ARTICLE Detection of catheter-related bloodstream infections by the Gram stain–acridine orange leukocyte cytospin test in hematopoietic stem cell transplant recipients A Abdelkefi, W Achour, L Torjman, T Ben Othman, S Ladeb, A Lakhal, H Allouche, A Ben Hassen and A Ben Abdeladhim Centre National de Greffe de Moelle Osseuse, Tunis, Tunisia In patients with central venous catheters (CVCs), catheter-related bloodstream infections (CRBI) are a prominent cause of morbidity, excess hospital costs, and in some cases mortality. The aim of this prospective study was to assess the validity of the Gram stain–acridine orange leukocyte cytospin (AOLC) test for the diagnosis of CRBI in hematopoietic stem cell transplant (HSCT) recipients with nontunnelled CVCs, using the differential- time-to-positivity (DTP)/clinical criteria as the criterion standard to define CRBIs. CVCs were externalized, nontunnelled, polyurethane double lumen catheters (Arrows, Readings, USA). All CVCs were placed in the subclavian vein by the infraclavicular approach, in the operating room. Catheters were inserted percutaneously, using the Seldinger technique. Study catheters were not exchanged over guidewires. Between May 2002 and December 2004, a total of 245 consecutive patients were included. Twenty-six of the 245 patients (10.6%) had CRBI as determined by the DTP method. The Gram stain–AOLC was positive in only two patients (7.6%) with a CRBI. Our results suggest that the Gram stain– AOLC test is not useful for the diagnosis of catheter- related bloodstream infection in HSCT recipients. Bone Marrow Transplantation (2006) 37, 595–599. doi:10.1038/sj.bmt.1705293; published online 6 February 2006 Keywords: Gram stain–acridine orange leukocyte cyto- spin; central venous catheter; catheter-related bloodstream infection; hematopoietic stem cell transplantation Introduction Central venous catheters (CVCs) are commonly used in hematopoietic stem cell transplant (HSCT) recipients for indications, such as monitoring of hemodynamics and administration of blood products, chemotherapy, parent- eral nutrition, and fluids. 1–3 Data from the National Nosocomial Infection Surveil- lance (NNIS) system (US) between January 1992 and February 1998 showed that catheter-related bloodstream infection (CRBI) was the third most frequent nosocomial infection and accounted for 14% of all nosocomial infections. 4 CRBIs prolong hospital stays from 7 to 21 days and account for an estimated increase in hospital costs of $ 3000–40 000 per patient. 5–7 In addition, an estimated 10–20% attributable mortality owing to nosocomial CRBI has been reported. 6 Only 20% of CVCs removed because of suspected infection actually prove to be infected, and the diagnosis is always retrospective. 8–10 Recently, it has been shown that CRBIs can be detected by the Gram stain and acridine orange leukocyte cytospin (AOLC) test 11 or the differen- tial-time-to-positivity (DTP) method, without catheter removal. 12,13 The aim of the present prospective study was to assess the validity of the Gram stain–AOLC test for the diagnosis of CRBI in HSCT recipients with nontunnelled CVCs, using the DTP/clinical criteria as the criterion standard to define CRBIs. Materials and methods Study design This prospective study was conducted between May 2002 and December 2004 at the ‘National Centre for Bone Marrow Transplantation’, Tunisia. This study was ap- proved by the hospital ethics committee and written consent was obtained from the patients or their legal representatives. Patients were eligible for the study if they were between 4 and 60 years of age, and required a HSCT for treatment of a hematologic malignancy. They also had to have neutropenia (absolute neutrophil count of o500/ml), a nontunnelled CVC in place, and fever as defined pre- viously. 14 Exclusion criteria were the presence of a CVC at admission, catheterization for o7 days, and a contraindication to the use Received 25 July 2005; revised 9 December 2005; accepted 12 December 2005; published online 6 February 2006 Correspondence: Dr A Abdelkefi, Centre National de Greffe de Moelle Osseuse, rue Jebel Lakhdar, 1006 Bab Saadoun, Tunis, Tunisia. E-mail: aabdelkefi@yahoo.fr Bone Marrow Transplantation (2006) 37, 595–599 & 2006 Nature Publishing Group All rights reserved 0268-3369/06 $30.00 www.nature.com/bmt