Abstract
BackgroundMulti-drug resistant bacteria are a phenomenon which is on the increase around the world, particularly with the emergence of colistin-resistant Enterobacteriaceae and vancomycin-resistant enterococci strains. The recent discovery of a plasmid-mediated colistin resistance with the description of the transferable mcr-1 gene raised concerns about the need for an efficient detection method for these pathogens, to isolate infected patients as early as possible. The LBJMR medium was developed to screen for all polymyxin-resistant Gram-negative bacteria, including mcr-1 positive isolates, and vancomycin-resistant Gram-positive bacteria.ResultsThe LBJMR medium was developed by adding colistin sulfate salt at a low concentration (4 μg/mL) and vancomycin (50 μg/mL), with glucose (7.5 g/L) as a fermentative substrate, to a Purple Agar Base (31 g/L). A total of 143 bacterial strains were used to evaluate this universal culture medium, and the sensitivity and specificity of detection were 100% for the growth of resistant strains. 68 stool samples were cultured on LBJMR, and both colistin-resistant Gram-negative and vancomycin-resistant Gram-positive strains were specifically detected.ConclusionsThe LBJMR medium is a multipurpose selective medium which makes it possible to identify bacteria of interest from clinical samples and to isolate contaminated patients in hospital settings. This is a simple medium that could be easily used for screening in clinical microbiology laboratories.
Highlights
Multi-drug resistant bacteria are a phenomenon which is on the increase around the world, with the emergence of colistin-resistant Enterobacteriaceae and vancomycin-resistant enterococci strains
Bacterial strains and samples cultured on LBJMR A total of 143 bacterial strains were used in this study, of which 101 were Enterobacteriaceae: 75 with an acquired mechanism of resistance to colistin, six with an intrinsic colistin resistance mechanism [38], and 20 colistin-susceptible strains (Additional file 1: Table S1)
68 samples were cultivated on LBJMR medium, including 66 stool samples (56 from humans and ten from chickens) that were previously screened for mcr-1 by RT-PCR (56 positive and ten negative) and two clinical rectal swabs obtained from patients in the La Timone hospital, from which a vancomycin-resistant E. faecium vancomycin-resistant enterococci (VRE) strain was isolated
Summary
Multi-drug resistant bacteria are a phenomenon which is on the increase around the world, with the emergence of colistin-resistant Enterobacteriaceae and vancomycin-resistant enterococci strains. Controlling the spread of these bacteria relies upon both reducing the prescription of antibiotics and preventing transmission from carrier patients to others [1] This prevention targets the emerging carbapenemase-producing Enterobacteriaceae and vancomycin-resistant enterococci (VRE) strains, with the development of specific detection methods, mostly based on chromogenic and selective culture media [2]. The increase in infections due to carbapenemaseproducing Enterobacteriaceae has led to the revival of Bardet et al BMC Microbiology (2017) 17:220 of colistin around 4 μg/ml, which is close to the clinical breakpoint of colistin resistance (> 2 μg/mL), according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) [20] Those data raised concerns about the detection and isolation of these pathogens, and the screening of the mcr-1 gene into carbapenemase-producing bacteria has been added to recommendations for clinical microbiology laboratories in France [21]. Given the diversity of mechanisms of colistin resistance [23], phenotypic methods, such as chromogenic culture media [2, 24] are preferred for a rapid detection
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
