Identification of bovine and porcine colistin-resistant mcr1-positive Escherichia coli.
Mainil, Jacques ; Muylaert, Adeline ; et al
Conference (2016, September)
OBJECTIVE Polymyxins, especially colistin, have been used for years in veterinary medicine and were rediscovered a few years ago as last resort antibiotics in human medicine against multi-resistant Gram ... [more ▼]
OBJECTIVE Polymyxins, especially colistin, have been used for years in veterinary medicine and were rediscovered a few years ago as last resort antibiotics in human medicine against multi-resistant Gram negative bacterial pathogens. For years, only chromosome-mediated resistance to colistin was identified as a consequence of mutation(s) in lipid A-encoding genes. Recently, however, a plasmid-located gene (mcr1) was identified in Gram-negative enterobacteria and has since been found by PCR in several, but not all, bovine, human, porcine and poultry colistin-resistant Escherichia coli (Liu YY et al. Lancet Infect Dis, 2016, 16(2), 161-168; Nordmann P and Poirel L. Clin Microbiol Infect, 2016, 22, 398-400 ; Schwarz S and Johnson AP. J Antimicrob Chemother, 2016, in press, doi: 10.1093/jac/dkw274). The purpose of this study was to compare phenotypic and genetic for the detection of resistance to colistin and of the mcr1 gene in a collection of Escherichia coli isolated from different animal species and from humans. METHODS More than 3000 E. coli isolates from cattle, pigs, dogs, cats, horses, rabbits, chickens ducks and humans were tested for resistance to colistin by growing them on agar plates with 1g/ml of colistin. The Minimal Inhibitory Concentrations (MIC) of and the presence of the mcr1 gene in all growing isolates were determined using the E test® and colony hybridization assay with a mcr1 specific gene probe, respectively. The probe-positive isolates were further tested with the mcr1 gene specific PCR. RESULTS A total of 410 E. coli isolated grew on 1g/ml colistin-containing agar plates. The majority of isolates grew well, but several grew sparsely with only few isolated colonies. As determined by the E test®, MIC of 273 isolates (67%) was 1g/ml of colistin and higher; conversely, MIC of 137 isolates (33%) was lower than 1g/ml of colistin. Of those 410 E. coli isolates, 34 from pigs and bovines (9% of isolates growing on colistin-containing agar plates; 25% of isolates with MIC higher than 1g/ml) hybridized with the mcr1 gene-derived probe: 5 from pigs and 11 from bovines gave black spots (including five from the same calf), while 18 from pigs and one from bovine gave grey spots. All but one pig isolate had a MIC between 1.5 and 16 g/ml of colistin. Fifteen “black spot” probe-positive isolates tested positive with the mcr1 gene specific PCR as did 3 porcine “grey spot” probe-positive isolates, while the remaining 16 isolates repeatedly tested negative even after lowering the annealing temperature. CONCLUSION This study confirms that (i) the results of phenotypic assays for the detection of colistin resistance can not be always trusted; (ii) the mcr1 gene is not the only one mechanism of resistance to colistin; (iii) mcr1 variants may exist that can not be detected by the classical PCR. Phenotypic assays like growth on colistin-containing agar plates can still represent a first base screening assay, although the MIC determination using the E test® confirms a >1g/ml MIC for only 2 out of 3 growing isolates. Presence of mcr1 gene and putative variants (like the most recently described mcr2 gene; Xavier BB et al., Eurosurveillance, 21, 7 July 2016) in all probe-positive isolates will be confirmed after Whole Genome Sequencing that will also allow comparing the mcr1-positive plasmids and isolates from pigs and cattle to similar human E. coli isolates. Further studies should also be performed to identify the colistin resistance mechanism in mec-negative isolates. [less ▲]Detailed reference viewed: 60 (1 ULg)
Minimal inhibitory concentrations of basil esesntial oil (Ocinum basilicum) against Salmonella enterica from livestock and application of the agar diffusion method
Duprez, Jean-Noël ; ; Muylaert, Adeline et al
Poster (2014, October)Detailed reference viewed: 22 (0 ULg)
Quinolones et fluoroquinolones : des décennies de développement et d'utilisation : Le point sur les molécules vétérinaires : partie 2, le regard du vétérinaire
Muylaert, Adeline ; Mainil, Jacques
in Annales de Médecine Vétérinaire (2014)Detailed reference viewed: 36 (6 ULg)
Résistance bactériennes aux antibiotiques, les mécanismes et leur "contagiosité"
Muylaert, Adeline ; Mainil, Jacques
in Annales de Médecine Vétérinaire (2013), 156Detailed reference viewed: 48 (2 ULg)
Résistances aux fluoroquinolones: la situation actuelle
Muylaert, Adeline ; Mainil, Jacques
in Annales de Médecine Vétérinaire (2013), 157Detailed reference viewed: 25 (2 ULg)
Antibiorésistance: une maladie génétique des bactéries.
Mainil, Jacques ; Mainil-Duchesnes, Christiane ; Muylaert, Adeline
Conference (2010)Detailed reference viewed: 25 (1 ULg)
Enterotoxaemia-like syndrome and Clostridium perfringens in veal calves
Muylaert, Adeline ; ; Duprez, Jean-Noël et al
in Veterinary Record : Journal of the British Veterinary Association (2010), 167Detailed reference viewed: 45 (3 ULg)
Prevalence, molecular typing, and antibiotic sensitivity of enteropathogenic, enterohaemorrhagic, and verotoxigenic Escherichia coli isolated from veal calves.
Bardiau, Marjorie ; Muylaert, Adeline ; Duprez, Jean-Noël et al
in Tijdschrift voor Diergeneeskunde (2010), 135(14-15), 554-8
Cattle are considered to be an important reservoir of enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains that can cause disease in humans, and numerous studies of ... [more ▼]
Cattle are considered to be an important reservoir of enterohaemorrhagic Escherichia coli (EHEC) and verotoxigenic Escherichia coli (VTEC) strains that can cause disease in humans, and numerous studies of the prevalence of these strains in cattle (focusing mainly on dairy and beef cattle) have been carried out in different regions of Europe, Asia, and America. To date, only a few studies of veal calves have been published focusing on EHEC strains belonging to the O157 serogroup EHEC, whereas EHEC and VTEC can belong to hundreds of different serotypes (many of which are as dangerous to humans as the O157:H7 EHEC, such as strains of the O26, O91, O103, O111, O113 and O145 serogroups). The aim of this study was to investigate the presence of enteropathogenic Escherichia coli (EPEC), EHEC, and VTEC strains in veal calves in Belgium and to characterize the positive isolates (serogroups, virulence-associated factor-encoding genes and antibiotic resistance profiles). The prevalence of EPEC, EHEC, and VTEC strains in faecal samples from veal calves in Belgium was found to be 11.7% (6.5% of the calves were found to be positive for EPEC strains, 2.6% for EHEC, and 3.9% for VTEC strains). No O157:H7 EHEC Strain was identified, but three calves were found to carry strains belonging to the O26 and O111 serogroups. The results of antibiotic sensitivity tests showed a high level of resistance (83% of strains were resistant or intermediate resistant to five or more antibiotics of the 13 tested antibiotics), which might be caused by the frequent use of antibiotics in veterinary practice. [less ▲]Detailed reference viewed: 28 (1 ULg)
Enteropathogenic (EPEC), enterohaemorragic (EHEC) and verotoxigenic (VTEC) Escherichia coli in wild cervids
Bardiau, Marjorie ; Grégoire, Fabien ; Muylaert, Adeline et al
in Journal of Applied Microbiology (2010), 109(6), 2214-2222Detailed reference viewed: 47 (6 ULg)