gms | German Medical Science

Objective: To evaluate the epidemiology and etiology of bacteremia among immunocompromised patients followed up at Baskent University Ankara Hospital from January 1st 2012 to July 30th 2013.

Materials and Methods: The immunocompromised patients who had ‘significant’ positive blood cultures which were isolated by automatic blood culture system BACTEC 9240 (Becton Dickinson^®) at the Microbiology Laboratuary of Baskent University Ankara Hospital were taken to the study. The definition of “immunocompromised patients” consisted of solid organ transplant recipients (kidney, liver) and hemato-oncologic malignancy patients with a history of chemotherapy in the last month before bacteremia. Every bacteremia and the patient were saved on a form with its demographic datas, laboratuary results, kind of bacteremia, the source of bacteremia, name and the antibiotic susceptibility of bacteria. Two classifications were used for the bacteremias. First classification was made according to source of bacteremia: as primary and secondary bacteremia. Primary bacteremias were divided into two groups; as catheter-related and catheter-unrelated. Second classification was made according to occurence of bacteremia; first bacteremia episode, concomitant, persistant and polymicrobial. The etiologic agents of bacteremia episodes were compared regarding the immunocompromised patient groups. SPSS version 11.0 was used for statistical analysis and p<0.05 was considered to be statistically significant. Pearson chi-square test was used as appropriate.

Results: This prospective study comprised of 167 bacteremia episodes in 130 consecutive immunocompromised patients. Fourty-nine of the episodes were seen in solid organ recipients and 118 episodes were seen in patients with malignancy. Twenty-nine patients had more than one bacteremia episodes. The distribution of 167 bacteremia episodes were: 145 (86.8%) first bacteremia episode, nine (5.4%) concomitant, eight (4.8%) persistant, five (3%) polymicrobial bacteremia. There were 87 primary (30% cathether-related, 70% cathether-unrelated) and 80 secondary bacteremias according to the source of bacteremias. The primary catheter-unrelated bacteremia was the most common type of bacteremia in patients with hematological malignancy but in all of the other immunsupressive groups (renal-liver transplantation, solid organ malignancy) secondary bacteremia was the most common type of bacteremia (p:0.016). Gram negative microorganisms were more commonly seen in secondary than primary bacteremias (p:0.000). Also gram negative bacterias were the most common agents in both transplant and malignancy groups. Escherichia coli was the most commonly isolated (46.1%) bacteria in this study. Fifty percent of the E.coli isolates were ESBL positive. Acinetobacter baumannii was the second most common gram negative agent and the ratio of XDR isolates among Acinetobacter isolates was 73%.

Conclusions: Gram negative bacteria are the most common causative agents of bacteremia in immunocompromised patients in our hospital. The rising ratio of XDR Acinetobacter baumannii is a striking problem which causes difficult-to-treat infections.