Bacteremias caused by Escherichia coli in cancer patients - analysis of 65 episodes.

OBJECTIVES: The aims of this study were to evaluate risk factors, clinical presentation, outcome and antimicrobial susceptibility in patients with Escherichia coli bacteremia occurring over seven years in a single cancer hospital. METHODS: Sixty five episodes of bacteremia from E. coli appearing over seven years from 12,301 admissions in a single cancer institution were retrospectively analyzed. RESULTS: The proportion of bacteremia caused by E. coli among Gram-negative bacteremia was 20.8% (the second most common organism after Pseudomonas aeruginosa), and infection-associated mortality was 17%. The incidence in 1989-1995 varied from 14.3 to 24.7%. The most common risk factors were: solid tumors as the underlying disease (70.7%); central venous catheter insertion (32.3%); prior surgery (46.2%), and prior chemotherapy within 48 h (44.4%). Neutropenia and urinary catheters did not place patients at high risk in any of the subgroups. When we compared the two subgroups of 61 cases of bacteremia - monomicrobial and polymicrobial (when E. coli was isolated from blood culture with another microorganism) - we found that acute leukemia and breakthrough (recurrence while receiving antibiotics) bacteremia were more frequently associated with polymicrobial E. coli bacteremia. There was also a difference in infection-associated mortality: monomicrobial bacteremia due to E. coli only had a significantly lower mortality in comparison with polymicrobial E. coli bacteremia (8.9 vs 35.0%, respectively; P<0.03). CONCLUSION: The susceptibility of 115 E. coli strains isolated from 65 episodes of bacteremia was stable. Only two episodes caused by quinolone-resistant strains occurred, both in 1995, after six years of using ofloxacin for prophylaxis in neutropenic patients in our hospital. We found that 85.2-91.3% of all strains were susceptible to aminoglycosides, 97.8% to quinolones, and 90-100% to third generation cephalosporins and imipenems. The patients most commonly infected had solid tumors and the mortality was only 17%.

Incidence, Clinical Features, Risk Factors and Outcome of Bacteremia due to Vancomycin-Resistant and Vancomycin-Sensitive Enterococcus Species Analyzed Over a 7-year Period in a Single Cancer Institution.

The aim of this study was to retrospectively compare the incidence, risk factors, and outcome in patients seen over a 7-year period at the National Cancer Institute in the Slovak Republic, with vancomycin-sensitive or vancomycin-resistant enterococcal bacteremia. The total incidence of enterococcal bacteremia at the National Cancer Institute increased from 5.1% in 1991 to 11.1% in 1993 and then decreased to 4.3% in 1995. Analysis of the 77 episodes of enterococcal bacteremia from 66 patients showed that 69 episodes from 60 patients were due to vancomycin-sensitive Enterococcus faecalis (group 1) and 8 episodes from 8 patients were due to vancomycin-resistant Enterococcus faecium (group 2). The features most frequently associated with enterococcal bacteremia were the insertion of a central venous catheter, neutropenia lasting more than 10 days, previous therapy with cephalosporins or vancomycin, previous prophylaxis with quinolones, and the incidence of superinfections. There was no difference in the clinical course or outcome between the 2 study groups. Previous therapy with aminoglycosides, cephalosporins, vancomycin or imipenem, neutropenia less than 10 days in length, malignancies other than leukemia or solid tumors, and the incidence of breakthrough bacteremia significantly correlated with patients with vancomycin-resistant E. faecium rather than patients with vancomycin-sensitive E. faecalis. The overall mortality was similar in both groups and averaged 32.5% for all enterococcal bacteremic patients. In this study, the major risk factors associated with cancer patients for developing vancomycin-resistant enterococcal bacteremia were previous therapy with aminoglycosides, cephalosporins or vancomycin, superinfections with other organisms and the incidence of breakthrough bacteremia.