Bloodstream infections in immunocompromised hosts

Immunocompromised hosts are at high risk for bloodstream infections (BSIs); the outcome is unpredictable (even with adequate therapy), frequently severe (mortality 27%). A 26 months survey in a haematology/oncology hospital was set-up; it comprised 158 patients and detected 171 positive blood cultures. The origin of the infections was primitive in 27.22% and secondary in 72.78% of the cases; the most frequent cause was the presence of a vascular catheter (23.41%). The second most important cause were the respiratory infections (19.62%), followed by the urinary tract infections (UTIs) (11.39%). Gram negative bacilli represented 59.4%, the enterobacteriaceae were predominant (35.59%), followed by Pseudomonas aeruginosa (10.73%) and species like Serratia marcescens and Acinetobacter baumannii. Although isolated at low level, they worry by an increasing frequency. Among Gram positive cocci (43.51%) coagulase negative staphylococci (CoNS) were the most frequent (25.42%), followed by Staphylococcus aureus (18.08%); Enterococcus faecalis (5.65%) was isolated from polymicrobial (associated) infections. The strains of E. coli, K. pneumoniae and P. aeruginosa were constantly susceptible to carbapenems, demonstrating otherwise various susceptibility patterns, generally elevated to the antibiotics we tested. The production of extended spectrum betalactamase (ESBL) was 22.58%. The methicillin resistance was 54.4% in S. aureus strains; the susceptibility was variable among 7 other antibiotics tested. One Staphylococcus strain had reduced susceptibility to vancomycin. A multidisciplinary survey is necessary for the control of the multidrug resistant organisms (MDRO).