engleski

Occurrence of bacterial pathogens in blood cultures and their antimicrobial susceptibility patterns at the University Hospital of Split

Bloodstream infections are often associated with high morbidity and mortality, especially those caused with multi-drug resistant bacteria (MDR). Timely diagnosis and appropriate treatment may help to improve the patients outcome. The aim of this study was to determine the most prevalent bacterial pathogens isolated from blood cultures and to analyse their antimicrobial susceptibility patterns at the University Hospital of Split (UHS). Methods: A retrospective study was conducted at the Department of Microbiology, University Hospital of Split in 2018. All bacterial pathogens isolated from blood cultures and their antimicrobial susceptibility were analysed. Duplicate isolates (positive cultures of the same strain within 14 days) were excluded from the evaluation. Results: A total of 1165 non-repetitive isolates were analysed. Gram-positive bacteria were isolated more often (66%) than Gram-negative ones. The most common isolated Gram-positive bacteria were coagulase-negative staphylococci (43.6%) and S. aureus (4.4%). The most common isolated Gram- negative bacteria were E. coli (10.7%), Klebsiella spp (7.0%) and Acinetobacter baumannii (4.1%). Methicillin resistant S. aureus showed high resistance to other antimicrobials as well (100% to ciprofloxacin, 62% to macrolides and clindamycin and 43% to gentamycin). E coli and K. pneumoniae showed significant resistance to ciprofloxacin (34 and 51%), trimethoprim/sulphametoxazole (42 and 33%) and gentamycin (22 and 43%), while 22% of E. coli and 35% of K. pneumoniae produced extended-spectrum beta-lactamases (ESBL). Moreover, the production of carbapenemases was detected for the first time in UHS (7% of K. pneumoniae isolates were Klebsiella pneumoniae carbapenemase (KPC)- producing bacteria (KPCs). All Acinetobacter baumannii isolates were MDR, sensitive only to colistin (100%), mostly sensitive to ampicillin/sulbactam (77%), and resistant to all other tested antibiotics. Conclusion: The emergence of multi-drug resistant bacteria in blood cultures, especially those that produce carbapenemases is worrisome and imposes the need for constant monitoring of antimicrobial susceptibility, in order to timely apply effective therapy.

bloodstream infections, antimicrobial susceptibility

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