Outcomes in UK patients with hospital-acquired bacteraemia and the risk of catheter-associated urinary tract infections

Abstract

Purpose: There is lack of contemporary outcome data on patients with hospital-acquired infections that cause bacteraemia. We determined the risk factors for 7-day mortality and investigated the hypothesis that, compared with central venous catheter (CVC)-associated bacteraemic infections, catheter-associated bacteraemic urinary tract infections (UTIs) were significantly associated with 7-day mortality.

Methods: From October 2007 to September 2008, demographical, clinical and microbiological data were collected on patients with hospital-acquired bacteraemia. Patients were followed until death, hospital discharge or recovery from infection. Risk factors for 7-day mortality were determined and multivariate logistic regression was used to define the association between catheter-associated bacteraemic UTIs and likelihood of death.

Results: 559 bacteraemic episodes occurred in 437 patients. Overall, there were 90 deaths (20.6%) at 7 days and 153 deaths (35.0%) at 30 days. Among patients with catheter-associated bacteraemic UTIs, 7-day and 30-day mortalities associated with each bacteraemic episode were 25/83 (30.1%) and 33/83 (39.8%), respectively. Within this subgroup, the commonest isolates were Escherichia coli, 36 (43.4%), Proteus mirabilis, 11 (13.3%) and Pseudomonas aeruginosa, 9 (10.8%). There were 22 (26.5%) multiple drug-resistant isolates and, of the E coli infections, 6 (16.7%) were extended spectrum β-lactamase producers. In univariate analysis, the variables found to have the strongest association with 7-day mortality were age, Pitt score, Charlson comorbidity index (CCI), medical speciality and site of infection. Compared with CVC-associated bacteraemic infections, there was a significant association between catheter-associated bacteraemic UTIs and 7-day mortality (OR 4.16, 95% CI 1.86 to 9.33). After adjustment for age and CCI, this association remained significant (OR 2.90, 95% CI 1.19 to 7.07).

Conclusions: Compared with CVC-associated bacteraemic infections, catheter-associated bacteraemic UTIs were significantly associated with 7-day mortality. Efforts to reduce these infections should be prioritised.

Keywords: Bacteraemia; Catheter associated UTI; Hospital-acquired.

Figure 1

Sites of infection in consecutive patients with hospital-acquired bacteraemia, expressed as percentages. This figure is only reproduced in colour in the online version.

Figure 2

Proportion of bacteraemic isolates causing catheter-associated urinary tract infections E. coli, Escherichia coli; P. mirabilis, Proteus mirabilis; P. aeruginosa, Pseudomonas aeruginosa; K. pneumoniae, Klebsiella pneumoniae; E. faecalis, Enterococcus faecalis; C. koseri, Citrobacter koseri; E. cloacae, Enterobacter cloacae; M. morganii, Morganella morganii; S. liquefacians, Serratia liquefacians; P. stuartii; Providencia stuartii; K. oxytoca, Klebsiella oxytoca; S. marcescens, Serratia marcescens; S. salivarus, Streptococcus salivarus. This figure is only reproduced in colour in the online version.