Value of integron detection for predicting antibiotic resistance in patients with Gram-negative septicaemia

Abstract

Multidrug-resistant Enterobacteriaceae are a major public health threat and complicate the choice of drugs for empirical antibiotic therapy, especially in sepsis patients who require rapid, appropriate treatment. The objective of this study was to examine the value of integrons as a global predictive marker of acquired antibiotic resistance in septicaemia-causing Enterobacteriaceae by direct detection in positive blood cultures. The integron genetic marker can be detected in a single test, whereas multiple PCRs are needed to detect the hundreds of known antibiotic resistance genes. A total of 166 positive blood cultures were included in the study, and integrons were detected with a quantitative PCR method both in positive blood cultures and isolated Enterobacteriaceae. The results of integron detection directly on positive blood cultures were consistent in 98.8% of cases with integron detection in isolated Enterobacteriaceae. Negative predictive values (NPVs) were >90% for resistance to third-generation cephalosporins, aminoglycosides, ciprofloxacin and trimethoprim/sulfamethoxazole. In the current context of antibiotic stewardship, these good NPVs indicate that this method might be useful for preserving broad-spectrum antibiotics. The results of this proof-of-concept study must be confirmed in order to demonstrate the clinical relevance of integron detection, not only in positive blood cultures but also, to gain time, in raw biological samples.

Keywords: Antibiotic resistance; Blood culture; Enterobacteriaceae; Genetic marker; Integron.