In vitro activity of iclaprim and comparator agents against Listeria monocytogenes clinical isolates from 2012 to 2018.

Objectives: This study examined the in vitro activity of iclaprim and comparators against 40 Listeria monocytogenes clinical isolates mostly (95%) from patients with bloodstream infection (BSI) from the USA, Australia/New Zealand, Latin America and Europe collected between 2012-2018.

Methods: Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Minimum inhibitory concentration (MIC) interpretations were based on CLSI criteria.

Results: The iclaprim MIC value for all L. monocytogenes was 0.015 μg/mL. The MIC values for iclaprim were 4-fold lower than trimethoprim, the only FDA-approved dihydrofolate reductase inhibitor, against all L. monocytogenes.

Conclusion: Iclaprim demonstrated lower MIC values than trimethoprim against a collection (2012-2018) of L. monocytogenes clinical isolates mostly from patients with BSI from the USA, Australia/New Zealand, Latin America and Europe.