Comparison of Glycopeptide-Resistant Enterococcus faecium Isolates and Glycopeptide Resistance Genes of Human and Animal Origins

Abstract

One hundred thirty-two glycopeptide-resistant Enterococcus faecium (GREF) isolates from different hospitals and pig and poultry farms in Belgium were compared on the basis of (i) their antibiotic susceptibilities, (ii) their SmaI pulsed-field gel electrophoresis (PFGE) patterns, and (iii) the organization of their Tn1546 or related elements in order to detect possible phenotypic and genotypic relationships among both groups of isolates. Human and animal vanA-positive GREF isolates were found to have similar susceptibility patterns; they remained susceptible to gentamicin and were, in general, susceptible to ampicillin. PFGE demonstrated a very high degree of genomic heterogeneity in both groups of isolates. However, indistinguishable isolates were found within different farms or hospitals, and in two instances, epidemiologically unrelated pig and human isolates showed indistinguishable PFGE patterns. In total, eight different transposon types were identified, and all were related to the prototype transposon Tn1546. The two predominant types, Tn1546 and type 2 transposons, which differed at three band positions, were present in both human and animal isolates. Type 2 transposons were significantly associated with pig isolates. The other types were seldom detected. These data suggest a possible exchange of glycopeptide resistance markers between animals and humans.

Horizontal transfer of antibiotic resistance from Enterococcus faecium of fermented meat origin to clinical isolates of E. faecium and Enterococcus faecalis

“…Although there were some close similarities in the PFGE patterns obtained, it was not possible to identify any significant association between enterococci isolated from fermented meat and human clinical samples. These results are consistent with previous work by Descheemaeker et al (1999) and Kim et al (2010) where a high level of genetic heterogeneity was observed between E. faecium strains from humans and animals. Similarly Castillo-Rojas et al (2013) also showed that enterococci isolated from humans and those isolated from the environment had high genetic diversity according to PFGE analysis.…”

Prevalence and Molecular Epidemiology of Glycopeptide‐Resistant Enterococci in Belgian Renal Dialysis Units

“…In the present study, different isolates belonging to particular E. faecium and E. faecalis clones were shown to harbor different transposon types, possibly the result of their horizontal spread. However, the stability of the transposons must also be questioned, because the transposon types most frequently detected differ only in a nucleotide change in the VANX gene and a deletion at the 5 end of the transposon [27,[56][57][58].…”

“…Transposon type 1, identical to the prototype transposon Tn1546 [29], was present in 19 (15.8%) of the strains studied. The second transposon type, differing from Tn1546 in 1 base substitution in the VANX gene [27], was present in 63 (52.5%) of the strains studied. No RFLP pattern could be obtained from the remaining strains; these probably represent additional transposon types.…”

“…The structure of the putative Tn1546 elements was analyzed by almost complete transposon amplification as described elsewhere [27], with the 25-bp forward primer ORF1-F1 (5 -AATCTTCATTAAAGCTAC-CTGTCCG-3 ) located at position 191 and the 25-bp reverse primer VanY-R1 (5 -TATCTCATAACGAAGATTAGTCGGC-3 ) located at position 9867 of transposon Tn1546 (GenBank accession no. M97297).…”

Host Specificity of Vancomycin‐ResistantEnterococcus faecium

“…has shown considerable DNA polymorphism in Tn1546 and has revealed the presence of common Tn1546 types among animal-and human-derived VREF strains, irrespective of the host strain [9,12,14,[17][18][19][20][21][22][23][24][25]. In addition, VREF strains from pigs predominantly carried a particular Tn1546 type with a specific point mutation at position 8234, whereas enterococci isolated from poultry predominantly contained Tn1546 subtypes harboring an IS1216V insertion in the vanX-vanY intergenic region [9,12,14,17,18,23].…”