Treatment of bloodstream infections in ICUs

Abstract

Bloodstream infections (BSIs) are frequent in ICU and is a prognostic factor of severe sepsis. Community acquired BSIs usually due to susceptible bacteria should be clearly differentiated from healthcare associated BSIs frequently due to resistant hospital strains. Early adequate treatment is key and should use guidelines and direct examination of samples performed from the infectious source. Previous antibiotic therapy knowledge, history of multi-drug resistant organism (MDRO) carriage are other major determinants of first choice antimicrobials in heathcare-associated and nosocomial BSIs. Initial antimicrobial dose should be adapted to pharmacokinetic knowledge. In general, a high dose is recommended at the beginning of treatment. If MDRO is suspected combination antibiotic therapy is mandatory because it increase the spectrum of treatment. Most of time, combination should be pursued no more than 2 to 5 days.Given the negative impact of useless antimicrobials, maximal effort should be done to decrease the antibiotic selection pressure. De-escalation from a broad spectrum to a narrow spectrum antimicrobial decreases the antibiotic selection pressure without negative impact on mortality. Duration of therapy should be shortened as often as possible especially when organism is susceptible, when the infection source has been totally controlled.

Figure 1

Decision tree including main determinants guiding the choice of the most appropriate antimicrobial therapy. (BSI: bloodstream infection; MDRO: multiresistant drug organism; TDM: therapeutic drug monitoring; MIC: minimum inhibitory concentration).