Glycopetide-dependent enterococcal bacteraemia following treatment of antibiotic-associated diarrhoea
Abstract number: P1826
Soleimanian S., Bean D., Wareham D.
Objectives: There are a small number of reports in which Gylcopeptide dependent enterococci (GDE) have been recovered from stool, intra abdominal collections, urine and rarely blood cultures. We describe a case of GDE bacteraemia and its possible risk factors.
Methods: A 21 year old female was admitted with a five day history of pyrexia, abdominal pain and vomiting. A diagnosis of severe necrotising pancreatitis was made and imipenem administered for seven days. Fourteen days after admission the patient developed severe diarrhoea and tested positive for Clostridium difficile toxin. Treatment with oral metronidazole and oral vancomycin was initiated and, after a further 48 hours, intravenous vancomycin and gentamicin were also, Vancomycin, intravenous and oral, was continued for sixteen days. On day 30 blood cultures became positive and a Gram stain revealed Gram-positive cocci in chains.
Results: The bottles were subcultured onto blood and chocolate agar. Examination of culture plates revealed no growth on any of the media except around both the vancomycin and teicoplanin discs on the sensitivity plates, suggesting a dependence on glycopeptides for growth. The concentration of glycopeptide required for growth was determined as 0.25 mg/L of vancomycin and 0.094 mg/L of teicoplanin. The organism was identified as Enterococcus faecium by DNA sequencing of the 16S rRNA gene. Susceptibility testing performed using IsoSensitest media supplemented with 8 mg/L vancomycin indicated resistance to amoxicillin and rifampicin, but susceptibility to linezolid and quinupristin/dalfopristin. The high level of resistance to vancomycin (MIC > 256 mg/L) and teicoplanin (MIC 32 mg/L) suggested carriage of the vanA gene which was confirmed by PCR.2 The organism reverted to non-dependence on standard media at a frequency of 2.6×10-3 with both dependent and revertant strains having identical genetic fingerprints when examined by pulsed field gel electrophoresis.
Conclusions: We emphasize on association between bacteraemia due to GDE, Clostridium difficile associated diarrhoea and prolonged IV and oral vancomycin therapy. As vancomycin at high doses (250 mg, 6 hourly) is now recommended by some authorities for the management of severe C. difficile diarrhoea this may facilitate further the problem of glycopeptide dependence in enterococci.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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