vanA-containing E. faecium isolates of clonal complex CC17 in clinical and environmental samples in a Tunisian hospital

Twenty-eight vancomycin (VA)-resistant enterococci isolated from different patients (n = 16) and also from the environment (n = 12) were recovered in a Tunisian military hospital during 2012-2013. The mechanisms of resistance to VA and to other antibiotics as well as the presence of esp and hyl virulence genes were determined in these isolates by PCR, being their clonal relationship analyzed by pulsed-field gel electrophoresis (PFGE). VA resistance mechanisms detected were as follows (species-patient/environment): vanA (Enterococcus faecium, 13/5), vanC1 (Enterococcus gallinarum, 3/0), and vanC2 (Enterococcus casseliflavus, 0/7). Most of the VA-resistant enterococci 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). The PFGE revealed the presence of 3 clones (A, B, C) and 1 closely related pattern (A1) among the 13 vanA-containing E. faecium isolates of patients showing 11 of them the A-A1 patterns. The clone A was also detected in all 5 environmental vanA-containing E. faecium isolates. Strains did not contain esp or hyl virulence genes. Multilocus sequence typing was performed in 4 E. faecium isolates representative of the 4 detected pulsotypes (A, A1, B, and C), and 2 different sequence types were identified (ST18 and ST80), both of them included in clonal complex CC17. These strains contained the IS16 element and showed ampicillin and ciprofloxacin resistance. VA resistance could be an emerging problem in Tunisia, and this is one of the first cases described so far in this country.