Bacterial resistance surveillance is one of the main outputs of microbiological laboratories and its results are important part of antimicrobial stewardship (AMS). In this study, the susceptibility of specific bacteria to selected antimicrobial agents was tested. The susceptibility of 90 unique isolates of pathogens of critical priority obtained from clinically valid samples of ICU patients in 2017-2021 was tested. 50% of these fulfilled difficult-to-treat resistance (DTR) criteria and 50% were susceptible to all antibiotics included in the definition. 10 Enterobacterales strains met DTR criteria, and 2 (20%) were resistant to colistin (COL), 2 (20%) to cefiderocol (FCR), 7 (70%) to imipenem/cilastatin/relebactam (I/R), 3 (30%) to ceftazidime/avibactam (CAT) and 5 (50%) to fosfomycin (FOS). For Enterobacterales we also tested aztreonam/avibactam (AZA) for which there are no breakpoints yet. The highest MIC of AZA observed was 1 mg/l, MIC range in the susceptible cohort was 0.032-0.064 mg/l and in the DTR cohort (incl. class B beta-lactamase producers) it was 0.064-1 mg/l. Two (13.3%) isolates of Pseudomonas aeruginosa (15 DTR strains) were resistant to COL, 1 (6.7%) to FCR, 13 (86.7%) to I/R, 5 (33.3%) to CAT, and 5 (33.3%) to ceftolozane/tazobactam. All isolates of Acinetobacter baumannii with DTR were susceptible to COL and FCR, and at the same time resistant to I/R and ampicillin/sulbactam. New antimicrobial agents are not 100% effective against DTR. Therefore, it is necessary to perform susceptibility testing of these antibiotics, use the data for surveillance (including local surveillance) and conform to AMS standards.

• Klíčová slova
• Antimicrobial stewardship, Aztreonam/avibactam, Cefiderocol, Ceftazidime/avibactam, Ceftolozane/tazobactam, Colistin, Difficult-to-treat resistance, Fosfomycin, Imipenem/cilastatin/relebactam,
• MeSH
• antibakteriální látky * farmakologie   terapeutické užití   MeSH
• azabicyklické sloučeniny * MeSH
• aztreonam MeSH
• cefalosporiny * MeSH
• cefiderokol MeSH
• gramnegativní bakterie MeSH
• kolistin farmakologie   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• Pseudomonas aeruginosa MeSH
• retrospektivní studie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky * MeSH
• avibactam MeSH Prohlížeč
• azabicyklické sloučeniny * MeSH
• aztreonam MeSH
• cefalosporiny * MeSH
• cefiderokol MeSH
• kolistin MeSH