engleski

BLOOD STREAM INFECTIONS IN PATIENTS UNDERGOING HSCT – THE RISING PROBLEM OFRESISTANT PATHOGENS

Bloodstream infections (BSI) are major cause of morbidity and mortality in patients undergoing hematopoeitic stem cell transplantation (HSCT). Knowledge of local microbiological epidemiology is a prerequisite for their optimal management. The aim of this study was to characterize the epidemiology of BSI in patients treated with HSCT in a single institution. 146 consecutive autologous HSCT performed between January 2008 and December 2009 in the Department of Hematology at University Hospital Centre Zagreb, were evaluated. Patients were followed up for one year after HSCT, blood culture dates and isolates were recorded. All patients received oral antimicrobial prophylaxis with ciprofloxacin and antifun¬gal prophylaxis with fluconazole from the beginning of conditioning therapy until fever, when empirical intravenous antimicrobials were started. Overall, 59 BSIs were detected at a median of 8 (range 4 to 358, SD 75) days post HSCT, with the majority of BSIs observed in the first month following HSCT, mostly (84.7% of all BSI) during the first 2 weeks. In total, 10 different microorganisms were identified as causative agents of BSIs. Gram positive pathogens were the most frequent etiologic agents, responsible for 71.2% of all BSIs. In this group, the most frequently isolated pathogens were Coagulase negative staphylococci which accounted for 55.9% of all BSI and 78.5% of all Gram positive BSIs. All these isolates were catheter re¬lated. Gram negative microorganisms accounted for 28.8% of all BSIs with the single most frequently isolated microorganism Pseudomonas aeruginosa. This pathogen accounted for 13.5% of all BSIs and for 47% of all Gram negative BSIs. Altogether, P. aeruginosa was isolated in 7 patients: 4 of these seven isolates were multidrug resistant (MDR), including resistance to carbapenems. All MDR isolates were sensitive only to colistin. Anaerobic bacteria were isolated in one patient There were no fungemias. In our study BSIs were a frequent complication of HSCT, with highest incidence during chemotherapy induced mucosal damage and neutropenia. Problem of infections caused by resistant microorganisms rises due to the broad use of antimicrobial prophylaxis. In our study we identified a high number of BSIs caused by Pseudomonas aeruginosa with more than 57% of these isolates showing multiple antibiotic resistance. The treatment of BSI-s caused by Pseudomonas aeruginosa remains a challenge because of the possibility that they may not always be covered with empirical therapy.

blood stream infections; stem cell transplantation

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