Rapid Detection of Polymyxin-Resistant Enterobacteriaceae from Blood Cultures.
Enterobacterial strains resistant to polymyxins are being increasingly reported worldwide. The conventional methods for detection of colistin-resistant isolates such as broth microdilution remain time-consuming (24 to 48 h), and methods such as disc diffusion and Etest are not reliable. Recently, the rapid polymyxin NP test was developed for rapid identification of polymyxin-resistant Enterobacteriaceae This test is based on the detection of glucose metabolism related to bacterial growth in the presence of a defined concentration of colistin (or polymyxin B). The formation of acid metabolites is evidenced by a color change of a pH indicator (red phenol) in less than 2 h. In this study, the polymyxin NP test was evaluated for detection of colistin-resistant Enterobacteriaceae directly from blood cultures. The test was performed with 73 blood culture sets (either spiked or clinical blood cultures) with various enterobacterial species. The test exhibited excellent discrimination between polymyxin-resistant and polymyxin-susceptible enterobacterial isolates, and results are obtained from blood cultures within 4 h. It is easy to perform and requires neither subculture nor a centrifugation step. This test is rapid, specific, and sensitive and allows early identification of polymyxin-resistant Enterobacteriaceae directly from blood cultures.
Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland INSERM European Unit (LEA Paris, France), University of Fribourg, Fribourg, Switzerland CNRS UMR5234, University of Bordeaux, Bordeaux, France.
Aurélie
A
Jayol
CNRS UMR5234, University of Bordeaux, Bordeaux, France.
Véronique
V
Dubois
Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland INSERM European Unit (LEA Paris, France), University of Fribourg, Fribourg, Switzerland.
Laurent
L
Poirel
Emerging Antibiotic Resistance Unit, Medical and Molecular Microbiology, Department of Medicine, University of Fribourg, Fribourg, Switzerland INSERM European Unit (LEA Paris, France), University of Fribourg, Fribourg, Switzerland University of Lausanne and University Hospital Center, Lausanne, Switzerland patrice.nordmann@unifr.ch.
Patrice
P
Nordmann
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000071997:Blood Culture / Q000379:methods*; D003116:Color; D024881:Drug Resistance, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011113:Polymyxins / Q000494:pharmacology*; D012680:Sensitivity and Specificity; D013997:Time Factors
D000900:Anti-Bacterial Agents; D007202:Indicators and Reagents; D011113:Polymyxins