Increasing burden of E. coli bacteraemia and changing epidemiology

Introduction / objectives

According to National surveillance in England S. aureus as a cause of bacteraemia has recently declined but that due to E. coli has increased by 33%. Mandatory reporting of E.coli is being introduced in 2011. At Imperial College Healthcare we investigated E. coli bacteraemia occurring between July 2008 and June 2010

Methods

Microbiological records of patients with E. coli bacteraemia were linked with patient data to determine their characteristics, whether CA or HA, and if the E. coli produced ESBL. Blood cultures taken within 2 days of admission were defined as CA, 2 days or more after admission as HA and a new episode if greater than 2 weeks between positive blood cultures. E. coli ESBL was defined by resistance to cefpodoxime, or by resistance to ceftazidime or cefotaxime whilst remaining susceptible to cefoxitin. Where possible, the potential source of the bacteraemia was determined from the antibiotic profile of E.coli isolated concurrently from other specimens.

Results

668 E. coli bacteraemia were detected (12% of all positive blood cultures), of which 67% were CA; 53% were female. For CA cases, the proportion of females (55%) was higher than males, whilst for HA cases, males accounted for more cases than females (47%). E, coli bacteraemia was more common in patients 65 years and over, accounting for 44% of CA and 49 % of HA cases. Of the 668, 110 (16%) produced ESBL, of which 61 (55%) were CA. Overall, 14% of CA and 22% of HA cases were ESBLs. The source was identified for 35% of cases; in 30% of these the urinary tract was responsible.

Conclusion

E.coli, is an important cause of CA and HA bacteraemia with a significant proportion ESBL-strains. Mandatory reporting may facilitate understanding of the epidemiology and target prevention strategies.

Disclosure of interest

None declared.