ABSTRACT
Frequency of bacterial co-infections among patients with COVID-19 is not high, and over-prescribing of antibiotics may contribute the selection of resistant strains of enterobacteria and gram-negative non-fermenting bacteria. The aim of the study was to assess the local features of antibiotic resistance of K. pneumoniae and its genetic mechanisms against background of the COVID-19 infection pandemic. Material and methods. There was selected 37 carbapenem-resistant K. pneumoniae strains isolated in 2016, 2017 and 2020 from hospitalized patients, including 15 strains, isolated from patients with COVID-19 infection. Minimal inhibitory concentrations (MICs) of meropenem and colistin were determined by broth microdilution method. Determination of MICs of eravacycline, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam was performed using Sensititre diagnostic system on EUMDROXF plates. Susceptibility to 11 combinations of 2 antibiotics was detected by modified method of multiply combination bactericidal testing. For 4 K. pneumoniae strains high-throughput sequencing was performed, followed with the subsequent search for determinants of antibiotic resistance and virulence, assessment of plasmid profiles. Results. All strains were resistant to meropenem (MIC50 32 mg/l, MIC90 128 mg/l) and produced KPC and OXA-48 carbapenemases. Strains isolated in 2016-2017 were susceptible to colistin (MIC <=2 mg/l), in 2020 only 26.7% of the strains retained their susceptibility (MIC50 64 mg/l, MIC90 256 mg/l). Susceptibility to combinations of two antibiotics with colistin included reduced from 84.6-100% in 2016-2017 till 26.6-66.7% in 2020. The strains isolated in 2020 retained their susceptibility to ceftazidime/avibactam (MIC <=1 mg/l). 5 strains resistant to cefiderocol with a MIC 8 mg/l were identified. Strains 2564 and 3125 isolated in 2020 from sputum of patients with COVID-19 infection belonged to different sequence-types (ST12 and ST23) and contained the blaOXA-48 carbapenemase gene, additionally strain 2564 contained the blaKPC-27carbapenemase gene. Resistance to colistin was caused by inactivation of the mgrB genes due to insertion of IS1 and IS5-like transposons. Conclusion. The performed genetic studies demonstrate a diversity of mechanisms of antibiotic resistance in K. pneumoniae leading to the formation of resistance including to antibiotics that haven't been used in Belarus till now.Copyright © 2021 Geotar Media Publishing Group. All Rights Reserved.
ABSTRACT
Background. The spread of extensive drug-resistance among gram-negative bacteria calls for the search for antimicrobics with new mechanisms of actions. The aim was to assess susceptibility of extensively drug-resistant K.pneumoniae strains to cefiderocol and other new inhibitor-protected beta-lactams, and to determine genetic mechanisms of antibiotic resistance. Methods. This study included 30 extensively drug-resistant K.pneumoniae strains collected in 2016-2021 from 4 regions of Belarus. Carbapenemase genes were detected by real-time PCR. Minimum inhibitory concentrations (MICs) for cefiderocol and other new antibiotics were assessed by microdilution method using the Sensititre system. Whole genome sequencing was performed for 2 resistant and 3 cefiderocol-susceptible strains. Genome assemblies and annotation were performed using UGENE v. 37.0 software. Nucleotide sequences were translated using CLC Sequence Viewer v. 8.0 (QIAGEN) package. The PROVEAN software was used to assess amino asides substitutions and their influence on the functional activity of proteins. Results. KPC carbapenemase-producers were 4 strains, OXA-48 - 17, KPC+OXA-48 - 1, NDM - 7, OXA-48 + NDM - 1. All KPC-producers were susceptible to imipenem/relebactam and meropenem/vaborbactam. Resistance to ceftazidime-avibactam was noted in all NDM producers and OXA-48+NDM co-producer. The study has identified 9 cefiderocol-resistant strains. These were NDM and OXA-48-producers isolated from hospitalized patients with COVID-19 infection from 3 regions of Belarus. Resistant strains had functionally significant nonsynonymous substitutions in the genes of TonB-dependent receptors for catecholate siderophores FepA (F472V, P64S) and Fiu (T92S). Conclusion. The study has shown high efficacy of new inhibitor-protected carbapenems and cephalosporins against certain types of carbapenemase-producers. Strains with mutational resistance to cefiderocol, an antibiotic not previously used in Belarus, have been identified.Copyright © Team of Authors, 2022.
ABSTRACT
Background. The spread of extensive drug-resistance among gram-negative bacteria calls for the search for antimicrobics with new mechanisms of actions. The aim was to assess susceptibility of extensively drug-resistant K.pneumoniae strains to cefiderocol and other new inhibitor-protected β-lactams, and to determine genetic mechanisms of antibiotic resistance. Methods. This study included 30 extensively drug-resistant K.pneumoniae strains collected in 2016–2021 from 4 regions of Belarus. Carbapenemase genes were detected by real-time PCR. Minimum inhibitory concentrations (MICs) for cefiderocol and other new antibiotics were assessed by microdilution method using the Sensititre system. Whole genome sequencing was performed for 2 resistant and 3 cefiderocol-susceptible strains. Genome assemblies and annotation were performed using UGENE v. 37.0 software. Nucleotide sequences were translated using CLC Sequence Viewer v. 8.0 (QIAGEN) package. The PROVEAN software was used to assess amino asides substitutions and their influence on the functional activity of proteins. Results. KPC carbapenemase-producers were 4 strains, OXA-48 — 17, KPC+OXA-48 — 1, NDM — 7, OXA-48 + NDM — 1. All KPC-producers were susceptible to imipenem/relebactam and meropenem/vaborbactam. Resistance to ceftazidime-avibactam was noted in all NDM producers and OXA-48+NDM co-producer. The study has identified 9 cefiderocol-resistant strains. These were NDM and OXA-48-producers isolated from hospitalized patients with COVID-19 infection from 3 regions of Belarus. Resistant strains had functionally significant nonsynonymous substitutions in the genes of TonB-dependent receptors for catecholate siderophores FepA (F472V, P64S) and Fiu (T92S). Conclusion. The study has shown high efficacy of new inhibitor-protected carbapenems and cephalosporins against certain types of carbapenemase-producers. Strains with mutational resistance to cefiderocol, an antibiotic not previously used in Belarus, have been identified. © Team of Authors, 2022.
ABSTRACT
Frequency of bacterial co-infections among patients with COVID-19 is not high, and over-prescribing of antibiotics may contribute the selection of resistant strains of enterobacteria and gram-negative non-fermenting bacteria. The aim of the study was to assess the local features of antibiotic resistance of K. pneumoniae and its genetic mechanisms against background of the COVID-19 infection pandemic. Material and methods. There was selected 37 carbapenem-resistant K. pneumoniae strains isolated in 2016, 2017 and 2020 from hospitalized patients, including 15 strains, isolated from patients with COVID-19 infection. Minimal inhibitory concentrations (MICs) of meropenem and colistin were determined by broth microdilution method. Determination of MICs of eravacycline, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam was performed using Sensititre diagnostic system on EUMDROXF plates. Susceptibility to 11 combinations of 2 antibiotics was detected by modified method of multiply combination bactericidal testing. For 4 K. pneumoniae strains high-throughput sequencing was performed, followed with the subsequent search for determinants of antibiotic resistance and virulence, assessment of plasmid profiles. Results. All strains were resistant to meropenem (MIC50 32 mg/l, MIC90 128 mg/l) and produced KPC and OXA-48 carbapenemases. Strains isolated in 2016–2017 were susceptible to colistin (MIC ≤2 mg/l), in 2020 only 26.7% of the strains retained their susceptibility (MIC50 64 mg/l, MIC90 256 mg/l). Susceptibility to combinations of two antibiotics with colistin included reduced from 84.6–100% in 2016–2017 till 26.6–66.7% in 2020. The strains isolated in 2020 retained their susceptibility to ceftazidime/avibactam (MIC ≤1 mg/l). 5 strains resistant to cefiderocol with a MIC 8 mg/l were identified. Strains 2564 and 3125 isolated in 2020 from sputum of patients with COVID-19 infection belonged to different sequence-types (ST12 and ST23) and contained the blaOXA-48 carbapenemase gene, additionally strain 2564 contained the blaKPC-27carbapenemase gene. Resistance to colistin was caused by inactivation of the mgrB genes due to insertion of IS1 and IS5-like transposons. Conclusion. The performed genetic studies demonstrate a diversity of mechanisms of antibiotic resistance in K. pneumoniae leading to the formation of resistance including to antibiotics that haven’t been used in Belarus till now. © 2021 Geotar Media Publishing Group. All Rights Reserved.