Diversity of Clones and Genotypes Among Vancomycin-Resistant Clinical Enterococcus Isolates Recovered in a Spanish Hospital

Forty-three vancomycin-resistant enterococci (VRE) from different patients were recovered in a Spanish Hospital (2003-2010), representing 0.4% of the total of enterococci recovered. Mechanisms detected were vanA (five Enterococcus faecium, two E. faecalis), vanB2 (seven E. faecium, five E. faecalis), vanB1 (one E. faecalis), and vanC1/2 (22 E. gallinarum, 1 E. casseliflavus). Four different Tn1546 structures were found among the seven vanA strains, three of them with insertions (ISEf1 or IS1542) or deletions. Most of the VRE presented a multiresistance phenotype and harbored different resistance genes [erm(B), tet(M), tet(L), ant(6)-Ia, aac(6')-aph(2 ''), aph(3')-IIIa, and catA]. Sixteen unrelated pulsotypes were detected among the 20 vanA/vanB E. faecalis and E. faecium isolates by pulsed-field-gel-electrophoresis and 11 unrelated pulsotypes among the 22 E. gallinarum isolates. Six different sequence types (ST) were demonstrated among the 12 vancomycin-resistant E. faecium strains (one of them new), and 5 were included into the clonal-complex (CC) CC17. Five different ST were detected among the eight E. faecalis strains. The esp gene was detected in 58% and 25% of E. faecium and E. faecalis strains, respectively, and the hyl gene in 78% and 89%, respectively. A high diversity of clones and genotypes of VRE were detected in this hospital.