Bloodstream Infections in the Intensive Care Unit: A Single-Center Retrospective Bacteriological Analysis Between 2007 and 2019

Hospital-acquired bloodstream infections are a severe worldwide problem associated with significant morbidity and mortality. This retrospective, single-center study aimed to analyze bloodstream infections in patients hospitalized in the intensive care unit of the Military Institute of Medicine, Poland. Data from the years 2007–2019 were analyzed. When the infection was suspected, blood samples were drawn and analyzed microbiologically. When bacterial growth was observed, an antimicrobial susceptibility/resistance analysis was performed. Among 12,619 analyzed samples, 1,509 were positive, and 1,557 pathogens were isolated. In 278/1,509 of the positive cases, a central line catheter infection was confirmed. Gram-negative bacteria were the most frequently (770/1,557) isolated, including Acinetobacter baumannii (312/770), Klebsiella pneumoniae (165/770; 67/165 were the isolates that expressed extended spectrum beta-lactamases (ESBL), 5/165 isolates produced the New Delhi metallo-β-lactamases (NDM), 4/165 isolates expressed Klebsiella pneumoniae carbapenemase (KPC), and 1/165 isolate produced OXA48 carbapenemase), Pseudomonas aeruginosa (111/770; 2/111 isolates produced metallo-β-lactamase (MBL), and Escherichia coli (69/770; 11/69 – ESBL). Most Gram-positive pathogens were staphylococci (545/733), mainly coagulase-negative (368/545). Among 545 isolates of the staphylococci, 58 represented methicillin-resistant Staphylococcus aureus (MRSA). Fungi were isolated from 3.5% of samples. All isolated MRSA and methicillin-resistant coagulase-negative Staphylococcus (MRCNS) strains were susceptible to vancomycin, methicillin-sensitive Staphylococcus aureus (MSSA) isolates – to isoxazolyl penicillins, and vancomycin-resistant Enterococcus (VRE) – to linezolid and tigecycline. However, colistin was the only therapeutic option in some infections caused by A. baumannii and KPC-producing K. pneumoniae. P. aeruginosa was still susceptible to cefepime and ceftazidime. Echinocandins were effective therapeutics in the treatment of fungal infections.