Seven-Year Evolution of β-Lactam Resistance Phenotypes in Escherichia coli Isolated from Young Diarrheic and Septicaemic Calves in Belgium

peer reviewedAntimicrobial resistance is a major worldwide hazard. Therefore, the World Health Organization has proposed a classification of antimicrobials with respect to their importance for human medicine and advised some restriction of their use in veterinary medicine. In Belgium, this regulation has been implemented by a Royal Decree (RD) in 2016, which prohibits carbapenem use and enforces strict restrictions on the use of third- and fourth-generation cephalosporins (3 GC and 4 GC) for food-producing animals. Acquired resistance to β-lactam antibiotics is most frequently mediated by the production of β-lactamases in Gram-negative bacteria. This study follows the resistance to β-lactam antibiotics in Escherichia coli isolated from young diarrheic or septicaemic calves in Belgium over seven calving seasons in order to measure the impact of the RD. Phenotypic resistance to eight β-lactams was assessed by disk diffusion assay and isolates were assigned to four resistance profiles: narrow-spectrum β-lactamases (NSBL); extended-spectrum β-lactamases (ESBL); cephalosporinases (AmpC); and cephalosporinase-like, NSBL with cefoxitin resistance (AmpC-like). No carbapenemase-mediated resistance was detected. Different resistance rates were observed for each profile over the calving seasons. Following the RD, the number of susceptibility tests has increased, the resistance rate to 3 GC/4 GC has markedly decreased, while the observed resistance profiles have changed, with an increase in NSBL profiles in particular

Identification of b-Lactamase-Encoding (bla) Genes in Phenotypically b-Lactam-Resistant Escherichia coli Isolated from Young Calves in Belgium

peer reviewedThe bla genes identification present in 94 phenotypically resistant Escherichia coli isolated from feces or intestinal contents of young calves with diarrhea or enteritis in Belgium was performed by microarrays (MA) and whole genome sequencing (WGS). According to their resistance phenotypes to 8 b-lactams at the disk diffusion assay these 94 E. coli produced a narrow-spectrum-b-lactamase (NSBL), an extended-spectrum-b-lactamase (ESBL) or a cephalosporinase (AmpC). All ESBL-encoding genes identified by MA and WGS belonged to the blaCTX-M family, with a majority to the blaCTX-M-1 subfamily. Two different genes encoding an AmpC, blaCMY-2, and blaDHA-1 were detected in isolates with an AmpC phenotype. The blaTEM-1 and the blaOXA-1 were detected alone in isolates with a NSBL phenotype or in combination with ESBL-/AmpC-encoding bla genes. Furthermore, the WGS identified mutations in the ampC gene promoter at nucleotides -42 (C>T) and/or -18 (G>A) that could not be identified by MA, in several isolates with an AmpC-like resistance phenotype. No carbapenemaseencoding gene was detected. To our knowledge this is the first survey on the identification of bla genes in E. coli isolated from young diarrheic or septicemic calves in Belgium

Selection and characterization of anti-NDM-1 nanobodies

Selection and characterization of anti-NDM-1 nanobodies Cawez Frédéric1, Mercuri Paola Sandra1, Piccirilli Alessandra3, Perilli Mariagrazia3, Morales Yánez Francisco2, Dumoulin Mireille2 & Galleni Moreno1 Biological Macromolecules1, NEPTUN2, Center for Protein Engineering, InBioS, University of Liege, Belgium; Dept of Biotechnological and Applied Clinical Sciences3 , University of L'Aquila, Italy. The misuses of beta-lactam antibiotics lead to the selection of multidrug-resistant (MDR) bacteria which are unaffected by the presence antibiotics. Therefore, it is essential to develop new rapid diagnostic assays in order to circumvent the nosocomial infections. In addition, it is essential to develop new inhibitor's scaffolds able to block the beta-lactamase activity. To develop new inhibitors, one strategy consists to select VHH antibodies that serve to the development of new beta-lactamase inhibitors by peptidomimetics