Enterococcus faecium isolated from bone marrow transplant patients in Tunisia: high prevalence of antimicrobial resistance and low pathogenic power.
OBJECTIVE
Investigation of the occurrence and antibiotic susceptibility of Enterococcus faecium isolates, collected during four years from neutropenic patients at the Tunisian bone marrow transplantation centre.


METHODS
E. faecium strains were identified by conventional methods and by the Api20 Strep (Bio-Mérieux, France). Antibiotic susceptibility was determined by the disk diffusion method on Mueller-Hinton agar and interpreted as recommended by CA-SFM. MICs of ampicillin, vancomycin, and teicoplanin were determined by E-test method.


RESULTS
Two hundred and thirty five E. faecium isolates were recovered from stool cultures or rectal swabs (229), throat (three), urine (two), and pus of wound (one). None was responsible for bacteraemia. Ampicillin resistance, without production of beta-lactamase, was observed in 43.8% of isolates. All the isolates were susceptible to glycopeptides. High rates of resistance were observed: high-level resistance (HLR) to gentamicin (33.6%), HLR to kanamycin (55.7%), HLR to streptomycin (47.6%), erythromycin (86.4%), ciprofloxacin (78.7%), rifampicin (85%), and tetracycline (43%). Strains with HLR to gentamicin were significantly more resistant to ampicillin and streptomycin. Multiple drug resistance was observed in most isolates.


CONCLUSIONS
These findings demonstrated the low pathogenic power of E. faecium in our patients, and the high frequencies of resistance to ampicillin and aminoglycosides. In the absence of glycopeptide-resistance, vancomycin remains an alternative treatment against multidrug resistant strains.
Abbassi
M S
MS
Laboratory of the National Bone Marrow transplantation Centre, Street Djebel-Lakdhar, Bab-Saadoun, 1006 Tunis, Tunisia. salahtoumi_mohamed@yahoo.com
Achour
W
W
Touati
A
A
Ben Hassen
A
A
D000668:Ampicillin Resistance; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001424:Bacterial Infections / Q000188:drug therapy* / Q000453:epidemiology; D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D016984:Enterococcus faecium / Q000187:drug effects / Q000302:isolation & purification*; D005243:Feces / Q000382:microbiology; D006020:Glycopeptides / Q000494:pharmacology; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000635:transmission*; D006801:Humans; D011183:Postoperative Complications / Q000382:microbiology; D014416:Tunisia / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D006020:Glycopeptides