Mortality following bacteraemic infection caused by extended spectrum beta-lactamase (ESBL) producing E. coli compared to non-ESBL producing E. coli

To determine the differences in mortality and length of hospital stay in patients with bacteraemic infection caused by ESBL and non-ESBL producing Escherichia coli. Main outcome measures were mortality, time from bacteraemia to death and length of inpatient stay.From June 2003 to November 2005, we prospectively collected clinical and microbiological data on all adult patients with E. coli bacteraemia.ESBL producing E. coli caused 16/242 (6.6%) community-acquired and 30/112 (26.8%) hospital-acquired bacteraemic infections. The most common sites of infection were urine 239/354 (67.5%) and bile 41/354 (11.6%). All ESBL producers were resistant to cephalosporins. Resistance to ciprofloxacin, trimethoprim, gentamicin and amikacin were 42/46 (91.3%), 39/46 (84.8%), 14/46 (30.4%) and 2/46 (4.3%), respectively. A significantly higher proportion of patients died following a bacteraemic infection caused by ESBL producing E. coli, 28/46 (60.8%), compared to non-ESBL producing E. coli, 73/308 (23.7%). The adjusted odds ratio for death was 3.57 (95% CI 1.48-8.60, p<0.005). Delay in initiating an appropriate antibiotic was significantly associated with death and ESBL production. There was no significant difference between time from bacteraemia to death (median time 7 days (ESBL +ve group) vs 5 days (ESBL -ve group); p=0.69) and, in those who survived, length of inpatient stay (median time 9 days (ESBL +ve group) vs 12 days (ESBL -ve group); p=0.111).Mortality following bacteraemic infection caused by ESBL producing E. coli was significantly higher than non-ESBL producing E. coli. These findings have serious implications for antibiotic prescription, as cephalosporins are ineffective treatment for many E. coli infections.