AhR-activating pesticides increase the bovine ABCG2 efflux activity in MDCKII-bABCG2 cells

In bovine mammary glands, the ABCG2 transporter actively secretes xenobiotics into dairy milk. This can have significant implications when cattle are exposed to pesticide residues in feed. Recent studies indicate that the fungicide prochloraz activates the aryl hydrocarbon receptor (AhR) pathway, increasing bovine ABCG2 (bABCG2) gene expression and efflux activity. This could enhance the accumulation of bABCG2 substrates in dairy milk, impacting pesticide risk assessment. We therefore investigated whether 13 commonly used pesticides in Europe are inducers of AhR and bABCG2 activity. MDCKII cells expressing mammary bABCG2 were incubated with pesticides for up to 72 h. To reflect an in vivo situation, applied pesticide concentrations corresponded to the maximum residue levels (MRLs) permitted in bovine fat or muscle. AhR activation was ascertained through CYP1A mRNA expression and enzyme activity, measured by qPCR and 7-ethoxyresorufin-\u39f-deethylase (EROD) assay, respectively. Pesticide-mediated increase of bABCG2 efflux activity was assessed using the Hoechst 33342 accumulation assay. For all assays, the known AhR-activating pesticide prochloraz served as a positive control, while the non-activating tolclofos-methyl provided the negative control. At 10-fold MRL concentrations, chlorpyrifos-methyl, diflufenican, ioxynil, rimsulfuron, and tebuconazole significantly increased CYP1A1 mRNA levels, CYP1A activity, and bABCG2 efflux activity compared to the vehicle control. In contrast, dimethoate, dimethomorph, glyphosate, iprodione, methiocarb and thiacloprid had no impact on AhR-mediated CYP1A1 mRNA levels, CYP1A activity or bABCG2 efflux. In conclusion, the MDCKII-bABCG2 cell model proved an appropriate tool for identifying AhR- and bABCG2-inducing pesticides. This provides an in vitro approach that could reduce the number of animals required in pesticide approval studies

The ABCG2 efflux transporter from rabbit placenta: Cloning and functional characterization

AbstractIn human placenta, the ATP-binding cassette efflux transporter ABCG2 is highly expressed in syncytiotrophoblast cells and mediates cellular excretion of various drugs and toxins. Hence, physiological ABCG2 activity substantially contributes to the fetoprotective placenta barrier function during gestation. Developmental toxicity studies are often performed in rabbit. However, despite its toxicological relevance, there is no data so far on functional ABCG2 expression in this species. Therefore, we cloned ABCG2 from placenta tissues of chinchilla rabbit. Sequencing showed 84–86% amino acid sequence identity to the orthologues from man, rat and mouse. We transduced the rabbit ABCG2 clone (rbABCG2) in MDCKII cells and stable rbABCG2 gene and protein expression was shown by RT-PCR and Western blot analysis. The rbABCG2 efflux activity was demonstrated with the Hoechst H33342 assay using the specific ABCG2 inhibitor Ko143. We further tested the effect of established human ABCG2 (hABCG2) drug substrates including the antibiotic danofloxacin or the histamine H2-receptor antagonist cimetidine on H33342 accumulation in MDCKII-rbABCG2 or -hABCG2 cells. Human therapeutic plasma concentrations of all tested drugs caused a comparable competitive inhibition of H33342 excretion in both ABCG2 clones. Altogether, we first showed functional expression of the ABCG2 efflux transporter in rabbit placenta. Moreover, our data suggest a similar drug substrate spectrum of the rabbit and the human ABCG2 efflux transporter

Effects of ceftiofur treatment on the susceptibility of commensal porcine E.coli – comparison between treated and untreated animals housed in the same stable

Background Healthy farm animals have been found to act as a reservoir of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (E. coli). Therefore, the objective of the study was to determine the input of antimicrobial active ceftiofur metabolites in the stable via faeces and urine after intramuscular administration of the drug to pigs and the elucidation of the Escherichia coli ESBL resistance pattern of treated and untreated pigs housed in the same barn during therapy. Methods For determination of the minimal inhibitory concentration (MIC) the method of microdilutionaccording to the recommended procedure of the Clinical and Laboratory Standards Institute was used. Inaddition to that, a qualitative determination was performed by agar dilution. Unsusceptible E. coli speciesselected via agar dilution with cefotaxime were confirmed by MALDI-TOF and ESBL encoding genes wereidentified by PCR. The amounts of ceftiofur measured as desfuroylceftiofur (DFC) in the different probes (plasma, urine, faeces and dust) were analysed by UPLC-MS/MS. Results In a first experiment two groups of pigs (6 animals per group) were housed in the same barn in two separated boxes. One group (group B) were treated with ceftiofur according to the licence (3 mg/kg administered intramuscularly (i.m.) on three consecutive days, day 1–3). During a second treatment period (day 29–31) an increased rate of ESBL resistant E. coli was detectable in these treated pigs and in the air of the stable. Moreover, the second group of animals (group A) formerly untreated but housed for the whole period in the same stable as the treated animals revealed increased resistance rates during their first treatment (day 45–47) with ceftiofur. In order to investigate the environmental input of ceftiofur during therapy and to simulate oral uptake of ceftiofur residues from the air of the stable a second set of experiments were performed. Pigs (6 animals) were treated with an interval of 2 weeks for 3 days with different doses of ceftiofur (3 mg/kg, 1 mg/kg and 0.3 mg/kg i.m.) as well as with 3 mg/kg per os) and the renal and biliary excretion of ceftiofur as its active metabolite were measured in comparison to the plasma levels. In addition to that, probes of the sedimentation dust and the air of the stable were analysed for drug residues. Conclusion The present study shows that treatment of several animals in a stable with ceftiofur influences the resistance pattern of intestinal Escherichia coli of the treated as well as untreated animals housed in the same stable. During therapy with the drug which was administered by injection according to the licence we detected nameable amounts of ceftiofur and its active metabolites in the dust and air of the stable

Minimierung infektiöser Faktorenerkrankungen in der Rinderhaltung: Erarbeitung von Handlungsempfehlungen zur Minimierung von Faktorenerkrankungen in der Rinderhaltung

Die Schriftenreihe informiert über Möglichkeiten zur Minimierung infektiöser Faktorenerkrankungen in der Rinderhaltung. Projektziel war, die Haupteinflussfaktoren im Bereich der Haltung und des Managements zu bewerten, die zur Entstehung von ausgewählten infektiösen Faktorenkrankheiten führen. Die umfassende Analyse und die Verknüpfung der Ergebnisse aus Tierhygiene, Tiergesundheit und des Tierwohls sind geeignet, Schwachpunkte hinsichtlich der Betriebsabläufe und des Status’ der milchrinderhaltenden Betriebe zu identifizieren und daraus Maßnahmen zur Minimierung der infektiösen Faktorenkrankheiten abzuleiten. Redaktionsschluss: 14.02.202

Development of an electronic interface for transfer of antimicrobial administration data in dairy farms.

Surveillance of antimicrobial administration in livestock production is an important factor in global policies to reduce spreading of antimicrobial resistance. In recent years, many studies have been carried out concerning the usage of antimicrobials in animal production and in some countries recording of antimicrobial quantities dispensed to famers is mandatory. On cattle farms, antimicrobial treatments are recorded for fattening calves under 8 months of age and for fattening cattle older than 8 months in Germany and treatment frequencies are then calculated. However, with the entry into force of Regulation (EU) 2019/6 on 01/28/2022, antimicrobial monitoring will gradually be extended to all animal species and age groups. Therefore, an effective, fast and accurate transfer of data on the use of antimicrobials, especially in the field of livestock farming, into corresponding databases is required to determine the treatment frequencies for the individual animal species or types of use. For this purpose, an electronic interface was programmed to transfer the data on antimicrobial use in dairy cattle farms from a herd management software program directly into a database. To test the practicability and effectiveness of this interface, 10 dairy cattle farms from Saxony were initially selected. Based on an in-depth analysis of the treatment frequencies of antimicrobial administration of 7 different age groups of animals after a two-year observation period, the functionality of the electronic interface could be established. The greatest potential for reduction of antimicrobials is in newborn calves, as they represent the age group with the highest treatment frequency

Minimierung infektiöser Faktorenerkrankungen in der Rinderhaltung: Erarbeitung von Handlungsempfehlungen zur Minimierung von Faktorenerkrankungen in der Rinderhaltung

Die Schriftenreihe informiert über Möglichkeiten zur Minimierung infektiöser Faktorenerkrankungen in der Rinderhaltung. Projektziel war, die Haupteinflussfaktoren im Bereich der Haltung und des Managements zu bewerten, die zur Entstehung von ausgewählten infektiösen Faktorenkrankheiten führen. Die umfassende Analyse und die Verknüpfung der Ergebnisse aus Tierhygiene, Tiergesundheit und des Tierwohls sind geeignet, Schwachpunkte hinsichtlich der Betriebsabläufe und des Status’ der milchrinderhaltenden Betriebe zu identifizieren und daraus Maßnahmen zur Minimierung der infektiösen Faktorenkrankheiten abzuleiten. Redaktionsschluss: 14.02.202

Minimierung infektiöser Faktorenerkrankungen in der Rinderhaltung: Erarbeitung von Handlungsempfehlungen zur Minimierung von Faktorenerkrankungen in der Rinderhaltung

Die Schriftenreihe informiert über Möglichkeiten zur Minimierung infektiöser Faktorenerkrankungen in der Rinderhaltung. Projektziel war, die Haupteinflussfaktoren im Bereich der Haltung und des Managements zu bewerten, die zur Entstehung von ausgewählten infektiösen Faktorenkrankheiten führen. Die umfassende Analyse und die Verknüpfung der Ergebnisse aus Tierhygiene, Tiergesundheit und des Tierwohls sind geeignet, Schwachpunkte hinsichtlich der Betriebsabläufe und des Status’ der milchrinderhaltenden Betriebe zu identifizieren und daraus Maßnahmen zur Minimierung der infektiösen Faktorenkrankheiten abzuleiten. Redaktionsschluss: 14.02.202

Cross-sectional study on antibiotic usage in pigs in Germany.

To be able to analyze the relationship between the level of resistance and the use of antimicrobials, it is necessary to collect detailed data on antimicrobial usage. For this reason, data on antimicrobial use on 495 pig farms from entire Germany were collected and analyzed. In Germany, each application and dispensing of medicines to food-producing animals is documented in detail obligatorily by the veterinarian. This information was collected retrospectively for the year 2011. The analyses undertook separate examinations on the age groups sow, piglet, weaner and fattening pig; both the route of administration and indication per active ingredient, and active ingredient class, were evaluated. In total, 20,374 kg of antimicrobial substances were used in the study population. Tetracyclines were used in highest amounts, followed by beta-lactams, trimethoprim-sulfonamides and macrolides. Concerning the frequency of using an active substance per animal, polypeptides were most commonly administered. In all age groups, respiratory infections were the main indication for using antimicrobials, followed by intestinal diseases in piglets, weaners and fattening pigs and diseases of reproductive organs in sows. Over a period of 100 days, the median number of treatment days with one antimicrobial substance for piglets was 15 days, for weaners about 6 days, for fattening pigs about 4 days and for sows about 1 day. A multifactorial ANOVA was conducted to investigate which factors are associated with the treatment frequency. The factors "veterinarian" and "age group" were related to the treatment frequency, just as the interaction between "veterinarian" and "farm size" as well as the interaction between "veterinarian" and "age group"