Researchers Study Epidemiology, Etiology of Empiric Antimicrobial Treatment in BSI

Bloodstream infections (BSI) still account for significant morbidity and mortality. Rodriguez-Aguirregabiria et al. (2013) describe the epidemiology, etiology, sources and adequacy of empiric antimicrobial treatment in BSI in a retrospective study about all BSI diagnosed during one year. The pattern resistant pathogen study was an EPINE-EPPS project.

Three-hundred-forty patients were included. The median age was 74.5 years [interquartile range (IQR), 58.5-80.5]; acute physiology and chronic health evaluation (APACHE II) score was 13 (IQR, 7-29).

BSI were community-acquired in 56 percent of the cases. The most common source of BSI was urinary tract (48.3 percent ), intra-abdominal (25.6 percent ) and lower respiratory tract infections (18.6 percent ). The most commonly isolated microorganisms were: Escherichia coli, K. pneumoniae, S.aureus (15% oxacilin resistant) and S. pneumoniae. The 8.6 percent  of enterobacteracea family produced extended-spectrum B-lactamasas (ESBLs). Inappropriate treatment was observed in 24.5 percent  and crude mortality rate was 7.7 percent .

Twenty-eight percent of BSI were nosocomial-acquired. The sources of BSI were unknown in 31.7 percent of the cases and catheter-related in 25.7 percent. The secondary sources of BSI were intra-abdominal in 57 percent of the cases. The most common isolated microorganisms were: S.epidermidis and other coagulasa negative, Candida, S. aureus (36 percent oxacilin resistant) and E. coli. 25 percent of enterobacteracea family were ESBLs. The researchers found five BSI caused by Acitetobacter carbapenem (CPM) resistant and 2 BSI by P. aeruginosa CPM resistant. Inappropriate treatment was observed in 52.5 percent and mortality rate was 28.7 percent.

Healthcare-related BSI produced 15.1 percent of the cases. The source of BSI were unknown in 22.6 percent and catheter-related in 11.3 percent. The secondary sources of BSI were urinary tract (60 percent), intra-abdominal (31.4 percent) and respiratory tract infections(8.6 percent). The most common microorganisms were: E.coli, S.aureus (25 percent oxacilin resistant), S.epidermidis and K.pneumoniae. Inappropriate treatment was noticed in 34 percent and mortality rate was 17 percent.

The researchers conclude that knowledge of local epidemiology is important to improve empiric antimicrobial treatment and to reduce mortality-related inappropriate treatment.

Reference: Rodriguez-Aguirregabiria M, Gimenez-Julvez T, et al. Poster presentation P006 at 2nd International Conference on Prevention and Infection Control (ICPIC 2013): Highlights in bloodstream infections: where does the patient acquire the infection? Antimicrobial Resistance and Infection Control 2013, 2(Suppl 1):P6 doi:10.1186/2047-2994-2-S1-P6