Reduction of antibiotic use and antibiotic resistance in commercial poultry

Use of antibiotics for companion animals and livestock in the Netherlands has reduced by more than 60% over the last 10 years (SDa 2019; MARAN-2019). This reduction is the result of a change in policy towards the use of antibiotics in veterinary practice and is characterized by a series of coherent political decisions which changed the playing field for farmers and veterinarians considerably. In the years before 2009 the Netherlands was a high consumer of antibiotics in veterinary practice (Grave et al., 2010). The ban of antimicrobial growth promoters (AGPs) did not result in a reduction in total use since in the Netherlands the AGPs were fully replaced by antibiotics licensed for therapy. The total sales of all antibiotics remained stable at around 600 tons from 2000 to 2009.This use pattern resulted in high levels of antimicrobial resistance in bacteria from livestock and food thereof and high prevalence of Livestock Associated MRSA and ESBL-producing E. coli and Salmonella (MARAN, 2019; RIVM, 2009). Specifically, ESBL-producing isolates in the food chain were considered a risk for public health and their high prevalences, predominantly but not solely in poultry and poultry meat products were the direct reason to initiate the change in policy towards antibiotic use in animals.In this manuscript the trends in antibiotic use in poultry will be explored in the context of total use in livestock and its effect on the occurrence and trends in ESBL-producers and antimicrobial resistance in other bacterial species from poultry

Characteristics of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) rRNA genes of Apis mellifera (Insecta: Hymenoptera): structure, organization, and retrotransposable elements

As an accompanying manuscript to the release of the honey bee genome, we report the entire sequence of the nuclear (18S, 5.8S, 28S and 5S) and mitochondrial (12S and 16S) ribosomal RNA (rRNA)-encoding gene sequences (rDNA) and related internally and externally transcribed spacer regions of Apis mellifera (Insecta: Hymenoptera: Apocrita). Additionally, we predict secondary structures for the mature rRNA molecules based on comparative sequence analyses with other arthropod taxa and reference to recently published crystal structures of the ribosome. In general, the structures of honey bee rRNAs are in agreement with previously predicted rRNA models from other arthropods in core regions of the rRNA, with little additional expansion in non-conserved regions. Our multiple sequence alignments are made available on several public databases and provide a preliminary establishment of a global structural model of all rRNAs from the insects. Additionally, we provide conserved stretches of sequences flanking the rDNA cistrons that comprise the externally transcribed spacer regions (ETS) and part of the intergenic spacer region (IGS), including several repetitive motifs. Finally, we report the occurrence of retrotransposition in the nuclear large subunit rDNA, as R2 elements are present in the usual insertion points found in other arthropods. Interestingly, functional R1 elements usually present in the genomes of insects were not detected in the honey bee rRNA genes. The reverse transcriptase products of the R2 elements are deduced from their putative open reading frames and structurally aligned with those from another hymenopteran insect, the jewel wasp Nasonia (Pteromalidae). Stretches of conserved amino acids shared between Apis and Nasonia are illustrated and serve as potential sites for primer design, as target amplicons within these R2 elements may serve as novel phylogenetic markers for Hymenoptera. Given the impending completion of the sequencing of the Nasonia genome, we expect our report eventually to shed light on the evolution of the hymenopteran genome within higher insects, particularly regarding the relative maintenance of conserved rDNA genes, related variable spacer regions and retrotransposable elements

Kwaliteitscontrole van de nieuwe Europese gevoeligheidstest in 2013

Dit artikel beschrijft de resultaten van twee rondzendoefeningen voor antibioticumgevoeligheidstesten uitgevoerd in 2014 door veterinaire laboratoria en dierartsenpraktijken met de door hun gehanteerde standaardmethode. Het artikel bevat tevens een vergelijking van de kwaliteit van de resultaten van 2014 met de rondzendingen van 2013 (eerder gepubliceerd in dit tijdschrift: deel 138, aflevering 2). De methodes voor en uitvoering van gevoeligheidstesten in veterinaire laboratoria en dierenartsenpraktijken zijn in 2014 verder geharmoniseerd. Bovendien is er meer uniformiteit ontstaan in de keuze van de antibiotica in de testpanels. De verbeterde harmonisatie is het resultaat van de implementatie van adviezen van CVI en de GD en heeft geleid tot een verbetering van de testkwaliteit

Evaluation of Eight Different Cephalosporins for Detection of Cephalosporin Resistance in Salmonella enterica and Escherichia coli

This study evaluates the efficacy of eight different cephalosporins for detection of cephalosporin resistance mediated by extended spectrum beta-lactamases (ESBL) and plasmidic AmpC beta-lactamases in Salmonella and Escherichia coli. A total of 138 E. coli and 86 Salmonella isolates with known beta-lactamase genes were tested for susceptibility toward cefoperazone, cefotaxime, cefpodoxime, cefquinome, ceftazidime, ceftiofur, ceftriaxone, and cefuroxime using minimum inhibitory concentration determinations and disc diffusion. The collection consisted of 84 ampicillin-susceptible, 57 ampicillin-resistant but cephalosporin-susceptible, 56 ESBL isolates and 19 isolates with plasmidic AmpC, as well as 10 ampC hyper-producing E. coli. The minimum inhibitory concentration distributions and zone inhibitions varied with the tested compound. Ampicillin-resistant isolates showed reduced susceptibility to the cephalosporins compared to ampicillin-susceptible isolates. Cefoperazone, cefquinome, and cefuroxime were not useful in detecting isolates with ESBL or plasmidic AmpC. The best substances for detection were cefotaxime, cefpodoxime, and ceftriaxone, whereas ceftazidime and ceftiofur were not as efficient. Ceftriaxone may be the recommended substance for monitoring because of some ability in separating ampC hyper-producing E. coli from ESBL and plasmidic AmpC isolate

In vitro antibiotic susceptibility of Dutch Mycoplasma synoviae field isolates originating from joint lesions and the respiratory tract of commercial poultry

The in vitro susceptibility of 17 Dutch Mycoplasma synoviae isolates from commercial poultry to enrofloxacin, difloxacin, doxycycline, tylosin and tilmicosin was examined. Three isolates originated from joint lesions and 14 were from the respiratory tract. The type strain M. synoviae WVU 1853 was included as a control strain. Antibiotic susceptibility was tested quantitatively using the broth microdilution test. Based on initial and final minimum inhibitory concentration values, all tested isolates were susceptible to doxycycline, tylosin and tilmicosin. Two isolates from the respiratory tract were resistant to enrofloxacin and showed intermediate resistance to difloxacin

Molecular epidemiology of unilateral amyloid arthropathy in broiler breeders associated with Enterococcus faecalis

Although symmetrical polyarticular amyloidosis has been described extensively in brown layers, spontaneous unilateral amyloid arthropathy has not been described previously in chickens. Birds from nine flocks of broiler parent stock (PS) had unilateral lameness associated with severe swelling of the left hock joint and the caudal aspect of the metatarsus. Gross pathology was restricted to the left hock joint and the left digital flexor tendons in almost all cases, suggesting an association with administration of Marek's disease vaccine. Amyloid deposits were found in 83% (25/30) of affected joints by histological examination of Congo red stained sections. Systemic amyloidosis, involving mainly the liver and spleen, was found in 59% (10/17) of birds. Enterococcus faecalis was isolated from joints in 77% (23/30) of cases and Staphylococcus aureus was isolated from the joint in one case (1/30). Thirty-five E. faecalis isolates from joints, tendons and blood samples from birds in five affected PS flocks were compared using pulsed-field gel electrophoresis (PFGE) to separate genomic fragments after digestion with Sma I. All but one isolate had identical or closely related restriction endonuclease digestion (RED) patterns that were very similar to a known arthropathic and amyloidogenic E. faecalis isolate. A further 30 E. faecalis isolates from seven grandparent stock (GPS) flocks and two isolates from two unaffected PS flocks of the same genetic background were analysed by PFGE. Among these isolates, 11 originating from four GPS flocks had RED patterns identical to or closely related to the reference amyloid-inducing strain. Moreover, one E. faecalis isolate from amyloidotic joints of brown layers housed in California, USA was included in the analysis and appeared to be identical to the reference strain. This study showed that the E. faecalis isolates involved in these outbreaks of unilateral amyloid arthropathy in broiler breeders belonged to the same clone as that responsible for outbreaks in brown layers