Antibiotic resistance and the risk of recurrent bacteremia

Abstract

Background

Direct health effects of antibiotic resistance are difficult to assess. We quantified the risk of recurrent bacteremia associated with antibiotic resistance.

Methods

We extracted antimicrobial susceptibility testing data on blood isolates of Enterobacteriaceae, Pseudomonas spp., Enterococcus spp. and Staphylococcus aureus from the Dutch surveillance system for antimicrobial resistance between 2008 and 2017. First and first recurrent (4-30days) bacteremia episodes were categorized as susceptible, single non-susceptible or co-non-susceptible (I/R), to 3^rd generation cephalosporins -/+ carbapenems (Enterobacteriaceae), ceftazidime -/+ carbapenems (Pseudomonas spp.), aminopenicillins -/+ vancomycin (Enterococcus spp.), or MSSA/MRSA (S. aureus). We calculated absolute and relative risks of recurrent bacteremia after single- and co-non-susceptible vs. susceptible first bacteremia, estimated the crude population attributable effect of antibiotic resistance for the Netherlands, and calculated absolute risks of developing non-susceptible recurrent bacteremia after a susceptible first episode.

Results

Risk ratios for recurrent bacteremia after a first episode caused by a single- and co-non-susceptible bacteria, respectively, vs. susceptible first episodes, were 1.7 (95% CI 1.5-2.0) and 5.2 (2.1-12.4) for Enterobacteriaceae, 1.3 (0.5-3.1) and 5.0 (2.9-8.5) for Pseudomonas spp., 1.4 (1.2-1.7) and 1.6 (0.6-4.2) for Enterococcus spp., and 1.6 (1.1-2.4) for MRSA vs. MSSA. The estimated population annual number of recurrent bacteremias associated with non-susceptibility was 40. Risks of recurrent bacteremia caused by a non-susceptible pathogen after a susceptible first episode were at most 0.4% (Pseudomonas spp.).

Conclusions

Although antibiotic non-susceptibility was consistently associated with higher risks of recurrent bacteremia, the estimated number of additional recurrent episodes in the Netherlands (40 per year) was rather limited.