Outbreak of vancomycin-, ampicillin-, and aminoglycoside-resistant Enterococcus faecium bacteremia in an adult oncology unit

Abstract

An outbreak of bacteremia caused by Enterococcus faecium with high-level resistance to vancomycin (MIC of > or = 256 micrograms/ml), ampicillin (MIC of > or = 64 micrograms/ml), and gentamicin or streptomycin (MIC of > or = 2,000 micrograms/ml) occurred in an adult oncology unit from June 1991 to May 1992. Active surveillance for the presence of this organism in stool or perianal cultures was begun in September 1991. Between June 1991 and May 1992, seven patients with bacteremia and 22 noninfected carriers of the organism in stool were identified. The vanA gene, tested for by PCR and gene probe, was present in all isolates evaluated. All bacteremic patients also had resistant E. faecium present in a stool or perianal culture; the stool isolates tested were closely related to the respective blood isolates as determined by pulsed-field gel electrophoresis. Antibiotic regimens using high-dose ampicillin and an aminoglycoside were ineffective with four patients. Five patients (71%) had multiple positive blood cultures; four of these patients died. Following a multiple logistic regression analysis, it was found that bacteremic patients received a significantly greater number of total antibiotic days compared with noninfected stool carriers (P = 0.019). The emergence of E. faecium with high-level resistance to vancomycin, ampicillin, and aminoglycosides underscores the importance of performing susceptibility testing on all clinically significant isolates. In the neutropenic adult oncology patient, bacteremia with this organism is of probable gastrointestinal origin, is often persistent, and is refractory to treatment with ampicillin in combination with an aminoglycoside. Prolonged use of antibiotics may predispose patients with gastrointestinal colonization to develop bacteremia.

An outbreak of vancomycin-resistant Enterococcus faecium in liver transplant recipients

“…The most frequent risk factors found included vancomycin use, cephalosporin use, highacuity illness, and immunosuppression. [3][4][5][6] In our study of liver transplant recipients, some of these factors were also found. However, we also identified frequent biliary tract manipulation as a risk factor, suggesting that recipients with biliary complications were at a greater risk for invasive infection.…”

“…2 Other centers have identified several risk factors for VREF infection, including empirical broad-spectrum antibiotic therapy, prolonged vancomycin therapy, prolonged hospitalization, and immunosuppression. [3][4][5][6][7] From August through November 1993, 8 liver transplant recipients developed infections with VREF in our institution. While undertaking an epidemiology study, microbiological studies were also performed.…”

Incidence and outcome of vancomycin-resistant enterococcal bacteremia following autologous peripheral blood stem cell transplantation

“…Resistance to vancomycin is generally associated with resistance to aminoglycosides and ampicillin making these organisms virtually untreatable with commonly utilized antimicrobial chemotherapy. 15,16 At present, VRE is a common intestinal colonizer among hospitalized individuals. 5 Vancomycin-resistant E. faecium has been isolated increasingly among patients in intensive care units.…”

Antibiotic-resistant strains of Enterococcus isolated from Swedish and Danish retailed chicken and pork

“…However, Ent. faecium has attracted special attention for its more recent association with clinical infections together with its disposition to acquire multiresistance against antibiotics (Gordon et al 1992;Gray et al 1994;Montecalvo et al 1994), a resistance often associated with conjugative plasmids (Leclercq et al 1989;Evers et al 1996).…”