Detection of Carbapenem-Resistant Enterobacterales in Simulated Blood Culture in 15 Minutes.

Daria Baer,Avi Peretz,Maya Azrad,Nora Saleh

doi:10.3390/life11020145

Daria Baer, Avi Peretz + Show 2 more

Open Access

https://doi.org/10.3390/life11020145

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Abstract

Bacteremia leading to sepsis and organ dysfunction is a life-threatening situation, leading to death of up to one fourth of the infected individuals around the world. One major challenge in the treatment of sepsis is the rising prevalence of antibiotic resistant bacteria, such as carbapenem-resistant Enterobacterales (CRE). In recent years, several molecular assays have been developed for the detection of CRE mechanisms, enabling rapid results reporting. We evaluated the performance of the NG-Test CARBA 5 (NG Biotech) kit in detection of CRE in simulated blood cultures. Carbapenemase-producing (CP) CRE isolates (n = 38) and non-carbapenemase CRE (Non-CP) isolates (n = 10), previously identified using the routine methods practiced at the clinical microbiology laboratory of the Baruch Padeh Medical Center, Israel, were used in this analysis. Variable concentrations of the bacterial isolates were added to a suspension composed of human blood and saline, simulating the composition of a blood culture. Samples were then transferred to an anaerobic blood culture bottle and later tested with the NG-Test CARBA 5 (NG Biotech) kit, that identifies the CRE mechanism within 15 min. The NG-Test CARBA 5 kit correctly identified 43 samples (89.5%). The sensitivity and specificity of the kits were 86.8% and 100%, respectively. In conclusion, the NG-Test CARBA 5 kit is a reliable and accessible tool for the rapid diagnosis of CRE bloodstream infections.

Highlights

Bloodstream infections (BSI) are a leading cause of morbidity and mortality worldwide [1,2]
Diagnosis of BSI is primarily blood culture (BC)-based, involving injection of patient blood into a bottle containing liquid culture medium, which is placed into a designated incubator that monitors bacterial growth by means of CO2 measurements [3]
Mortality risk associated with CP-carbapenem-resistant Enterobacterales (CRE) infections is 3– 6 times higher compared to that of infections caused by non-resistant bacteria [12]

Summary

Introduction

Bloodstream infections (BSI) are a leading cause of morbidity and mortality worldwide [1,2]. When bacterial growth is identified, the laboratory staff samples the respective BC bottle, performs Gram staining and inoculates the sample on solid agar medium, together resulting in the prolonged turnaround time of pathogen identification in BSI (at least 24–48 h, depending on the organism). Antibiotic susceptibility testing (AST), which can only be performed after the growth of the pathogen colonies on solid medium, demands approximately 24 h. Each delay in pathogen identification and antibiotic treatment adjustment has serious clinical implications, with regards to infections with multidrug resistant bacteria, such as carbapenem-resistant Enterobacterales (CRE) [4,5,6]. Rapid assays for pathogen identification in BSI are needed

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