[Characteristics of Enterococcus strains isolated from neutropenic patients at the National Bone-Marrow Transplantation Center of Tunis].

The frequency of digestive colonization of neutropenic patients by Enterococci during the phase of pre-transplant and post-transplant of bone marrow is important indeed as 441 Enterococcus spp strains have been isolated from stool-cultures and other specimens whithin a period of 35 months in 80 patients. A quantitative stool culture was done on appropriate media. Simple bile-esculine agar (BE) and bile esculine-agar additionned with 6 mg/l of vancomycine (BEV) were used for detecting Enterococci. These organisms were taken into account, when then numeration was > 10(3) UFC/g of fecal sample on BE and in all cases on BEV. Species isolated were essentially Enterococcus faecalis (39.4%), Enterococcus faecium (34.4%) and Enterococcus casseliflavus (17%). These strains were characterized by a high frequency of high-level resistance to gentamicin (40.8%). Resistance to amoxicillin concerns 40% of E. faecium strains. Seventeen multiresistant strains of E. faecium isolated from 7 patients (colonized during a long period and receiving a gut decontamination treatment) were the subject of a phenotypic analysis (biotyping, antibiotyping and determination of MICs to beta-lactam, aminoglycosides and glycopeptides). This analysis showed that these strains are distinguishable, endogenic and specific for each patient, the common multiresistance trait resulted from the selective pressure of decontamination treatment used for our patient.