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INTRODUCTION: Increasing incidence of Enterococcus faecium resistant to key antimicrobials used in therapy of hospitalized patients is a worrisome phenomenon observed worldwide. Our aim was to characterize a tigecycline-, linezolid- and vancomycin-resistant E. faecium isolate with the vanA and vanB genes, originating from a hematoma of a patient hospitalized in an intensive care unit in Poland. METHODS: Antimicrobial susceptibility (a broad panel) was tested using gradient tests with predefined antibiotic concentrations. The complete genome sequence was obtained from a mixed assembly of Illumina MiSeq and Oxford Nanopore's MinION reads. The genome was analyzed with appropriate tools available at the Center for Genomic Epidemiology, PubMLST and GenBank. Transferability of oxazolidinone, tigecycline and vancomycin resistance genes was investigated by conjugation, followed by PCR screen of transconjugants for antimicrobial resistance genes and plasmid rep genes characteristic for the donor and genomic sequencing of selected transconjugants. RESULTS: The isolate was resistant to most antimicrobials tested; susceptibility to daptomycin, erythromycin and chloramphenicol was significantly reduced, and only oritavancin retained the full activity. The isolate represented sequence type 18 (ST18) and carried vanA, vanB, poxtA, fexB, tet(L), tet(M), aac(6')-aph(2''), ant(6)-Ia and ant(6')-Ii. The vanA, poxtA and tet(M) genes located on ~ 40-kb plasmids were transferable by conjugation yielding transconjugants resistant to vancomycin, linezolid and tigecycline. The substitutions in LiaS, putative histidine kinase, SulP, putative sulfate transporter, RpoB and RpoC were potential determinants of an elevated daptomycin MIC. Comparative analyses of the studied isolate with E. faecium isolates from other countries revealed its similarity to ST18 isolates from Ireland and Uganda from human infections. CONCLUSIONS: We provide the detailed characteristics of the genomic determinants of antimicrobial resistance of a clinical E. faecium demonstrating the concomitant presence of both vanA and vanB and resistance to vancomycin, linezolid, tigecycline and several other compounds and decreased daptomycin susceptibility. This isolate is a striking example of an accumulation of resistance determinants involving various mechanisms by a single hospital strain.
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OBJECTIVE: The aim of this retrospective study was to estimate the prevalence of healthcare-associated infections (HAI), microbiological data including resistance patterns and impact of HAI on patients' survival. METHODS: Two-centre study on 172 patients was performed. Medical records of patients hospitalized in the two COVID-19 intensive care units (ICU) localized in Bydgoszcz between 1 October 2020 and 30 March 2021 were analysed retrospectively. Data collection included demographics, microbiological, clinical variables, and patient outcome. All infections were defined according to the HAI-Net ICU protocol of the European Centre for Disease Prevention and Control (ECDC). Detailed data concerning bloodstream infection (BSI), pneumonia (PN) and urinary tract infection (UTI) were collected. RESULTS: In 97 patients (56.4%), 138 HAI cases were identified. Patients with HAI statistically more often had been administered antimicrobial therapy prior to the admission to ICU (59.8% vs. 34.7%, p < 0.05), and needed catecholamines during hospitalization (93.8% vs. 70.7%, p < 0.001). The risk of HAI increased by 50% if antimicrobial therapy had been applied before the admission to ICU, and was three times higher if during the hospitalization in ICU catecholamines infusion was needed. Mortality was higher in patients diagnosed with HAI (72.2% vs. 65.3%) but the difference was not statistically significant (p = 0.34). CONCLUSIONS: Further investigation of co-infections in critically ill patients with COVID-19 is required in order to identify HAI risk factors, define the role of empiric antimicrobial therapy and proper prevention strategies.
