High abundance and diversity of antimicrobial resistance determinants among early vancomycin-resistant Enterococcus faecium in Poland

• Published in: European journal of clinical microbiology & infectious diseases 2013-09, Vol.32 (9), p.1193-1203
• Main Authors: Sadowy, E., Sieńko, A., Gawryszewska, I., Bojarska, A., Malinowska, K., Hryniewicz, W.
• Format: Article
• Language: English
• Subjects: Abundance; Amino acids; Ampicillin Resistance - genetics; Anti-Bacterial Agents - pharmacology; Antibiotic resistance; Antimicrobial agents; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Ciprofloxacin - pharmacology; DNA Gyrase - genetics; DNA Topoisomerase IV - genetics; DNA Transposable Elements - genetics; Drug resistance; Drug Resistance, Multiple, Bacterial - genetics; Enterococcus faecium; Enterococcus faecium - drug effects; Enterococcus faecium - genetics; Enterococcus faecium - isolation & purification; Enzymes; Epidemiology; Genes; Gentamicins - pharmacology; Hematology; Humans; Infectious diseases; Internal Medicine; Medical Microbiology; Medical sciences; Microbial Sensitivity Tests; Molecular Sequence Data; Mutation; Penicillin; Poland; Streptomycin - pharmacology; Tetracycline - pharmacology; Vancomycin - pharmacology; Vancomycin Resistance - genetics
• ISSN: 0934-9723; 1435-4373
• DOI: 10.1007/s10096-013-1868-y

The purpose of this study was to investigate the clonal structure, antimicrobial resistance phenotypes and their determinants among early vancomycin-resistant Enterococcus faecium (VREm) isolates in Poland. Two hundred and eighty-one VREm isolates collected between 1997 and 2005 were studied. VREm isolates were characterised by multilocus sequence typing (MLST). The presence of antimicrobial resistance determinants, transposon-specific genes, IS 16 and esp Efm was checked by polymerase chain reaction (PCR). Ciprofloxacin and ampicillin resistance determinants were investigated by sequencing. Two hundred and twenty-two (79 %) and 59 (21 %) VREm isolates were vanA - and vanB -positive, respectively. Among 135 representative isolates, MLST yielded 33 different sequence types (STs), of which 29 were characteristic of hospital-associated E. faecium ; 128 (94.8 %) and 123 (91.1 %) isolates harboured the IS 16 and esp Efm genes, and all 135 isolates were resistant to ciprofloxacin and ampicillin. Resistance to tetracycline (71.1 % isolates) was mostly associated with tetM (75.0 %) and the concomitant presence of the Tn 916 integrase gene. High-level resistance to streptomycin (93.3 % of isolates) and high-level resistance to gentamicin (94.1 % of isolates) were due to ant(6′)-Ia and aac(6′)-Ie-aph(2″) genes, respectively, the latter of which is known to be located on various Tn 4001 -type transposons. Fifteen combinations of mutations in the quinolone-determining regions of GyrA and ParC were identified, including changes not previously reported, such as S83F and A84P in GyrA. Twenty-three variants of the penicillin-binding protein PBP5 occurred in the studied group, and novel insertions at amino acid positions 433 and 568 were identified. This analysis revealed the predominance of hospital-associated strains of E. faecium , carrying an abundant and divergent range of resistance determinants among early VREm isolates in Poland.