Global prevalence of carbapenem resistance in neutropenic patients and association with mortality and carbapenem use: systematic review and meta-analysis.

Background: Carbapenem-resistant Gram-negative bacteria are recognized as a cause of difficult-to-treat infections associated with high mortality.

Objectives: To perform a systematic review of currently available data on distribution, characteristics and outcome associated with carbapenem-resistant bloodstream infections in adult neutropenic patients.

Methods: Included studies were identified through Medline, Embase and Cochrane databases between January 1995 and April 2016. Random effect meta-analysis was used to quantify the association between carbapenem resistance and mortality and between carbapenem exposure and resistance.

Results: A total of 30 studies from 21 countries were included. Overall carbapenem resistance varied from 2% to 53% (median 9%) among studies. Infections due to carbapenem-resistant Pseudomonas spp . were reported in 18 (60%) studies showing high median resistance rates (44% of all carbapenem-resistant Gram-negatives and 19% of Pseudomonas isolates). Resistance of Enterobacteriaceae was less commonly reported and bloodstream infections due to carbapenem-resistant Klebsiella spp. were mainly documented from endemic areas (Greece, Italy, Israel). Carbapenem resistance in Acinetobacter spp. was reported in 9 (30%) studies (median resistance 58% of Acinetobacter isolates). Mortality rates ranged from 33% to 71% (median 50%) in patients with carbapenem-resistant infections. Carbapenem resistance appeared to correlate with mortality (OR 4.89, 95% CI 3.30-7.26) and previous exposure to carbapenems (OR 4.63, 95% CI 3.08-6.96).

Conclusions: Carbapenem resistance represents a threat to neutropenic patients. In this group, resistance is likely promoted by previous carbapenem use and leads to high mortality rates. The knowledge of resistance patterns is crucial and can direct clinicians in the use of alternatives to carbapenem-based regimens.