Rapid immunochromatographic detection of carbapenemases directly from positive blood cultures in patients colonized by carbapenemase-producing bacteria

Abstract

Objective: Carbapenem resistance is increasing worldwide. Earlier detection of this resistance, combined with appropriate treatment, could improve the prognosis of bloodstream infection. This study aims to evaluate the detection of carbapenemase-producing Gram-negative bacteria directly from positive blood cultures to quickly adapt antibiotic therapy before the results of antibiotic susceptibility testing are available. Methods: A prospective single-centre study was conducted over a 5-month period at Lille University Hospital. Carbapenemase detection by immunochromatographic testing was performed directly from positive blood cultures with Gram-negative rods of 35 patients previously colonized with carbapenemase-producing bacteria. Results: Among these 35 positive blood cultures, 15 carbapenemase-producing strains were directly detected, mainly OXA-48 and NDM. This rapid procedure provided results in less than 1 h, compared to several hours for conventional methods. Of the patients with infections caused by carbapenemase-producing isolates, 67% (10 patients) received inappropriate empiric treatment, highlighting the potential of the rapid test to adjust antibiotic therapy sooner. Conclusions: Carbapenemase detection by immunochromatographic testing directly on blood culture pellets is reliable and can lead to early adaptation of antibiotic therapy in these severe infections.

Keywords

• Carbapenemases
• Immunochromatographic test
• Bloodstream infections
• Antibiotics
• Rapid diagnostics
• Antimicrobial stewardship