title: Detection of virulence factors in high-level gentamicin-resistant Enterococcus faecalis and Enterococcus faecium isolates from a Tunisian hospital.
abstract: Phenotypic and genotypic determination of virulence factors were carried out in 46 high-level gentamicin-resistant (HLGR) clinical Enterococcus faecalis (n=34) and Enterococcus faecium (n=12) isolates recovered from different patients in La Rabta Hospital in Tunis, Tunisia, between 2000 and 2003 (all these isolates harboured the aac(6')-aph(2") gene). The genes encoding virulence factors (agg, gelE, ace, cylLLS, esp, cpd, and fsrB) were analysed by PCR and sequencing. The production of gelatinase and hemolysin, the adherence to caco-2 and hep-2 cells, and the capacity for biofilm formation were investigated in all 46 HLGR enterococci. The percentages of E. faecalis isolates harbouring virulence genes were as follows: gelE, cpd, and ace (100%); fsrB (62%); agg (56%); cylLLS (41.2%); and esp (26.5%). The only virulence gene detected among the 12 HLGR E. faecium isolates was esp (58%). Gelatinase activity was detected in 22 of the 34 E. faecalis isolates (65%, most of them with the gelE+-fsrB+ genotype); the remaining 12 isolates were gelatinase-negative (with the gelE+-fsrB- genotype and the deletion of a 23.9 kb fragment of the fsr locus). Overall, 64% of the cylLLS-containing E. faecalis isolates showed beta-hemolysis. A high proportion of our HLGR E. faecalis isolates, in contrast to E. faecium, showed moderate or strong biofilm formation or adherence to caco-2 and hep-2 cells.
authors.affiliation: Laboratoire MBA, Département de Biologie, Faculté de Sciences de Tunis, Campus Universitaire, and Laboratoire de Bacteriologie, Hôpital La Rabta, Tunis, Tunisia.
authors.forename: N
authors.initials: N
authors.lastname: Klibi
authors.forename: K
authors.initials: K
authors.lastname: Ben Slama
authors.forename: Y
authors.initials: Y
authors.lastname: Sáenz
authors.forename: A
authors.initials: A
authors.lastname: Masmoudi
authors.forename: S
authors.initials: S
authors.lastname: Zanetti
authors.forename: L A
authors.initials: LA
authors.lastname: Sechi
authors.forename: A
authors.initials: A
authors.lastname: Boudabous
authors.forename: C
authors.initials: C
authors.lastname: Torres
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics; D018441:Biofilms; D018938:Caco-2 Cells; D002460:Cell Line; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D016984:Enterococcus faecium / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D005839:Gentamicins / Q000494:pharmacology*; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006761:Hospitals; D006801:Humans; D008826:Microbial Sensitivity Tests; D014416:Tunisia; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D005839:Gentamicins; D037521:Virulence Factors