The authors aimed to investigate eight strains of Escherichia coli (E. coli) strains from Hungarian layer flocks for antimicrobial resistance genes (ARG), using metagenomic methods. The strains were isolated from cloacal swabs of healthy adult layers. This study employed shotgun sequencing-based genetic and bioinformatic analysis along with determining phenotypic minimum inhibitory concentrations. A total of 59 ARGs were identified in the eight E. coli isolates, carrying ARGs against 15 groups of antibiotics. Among these, 28 ARGs were identified as transferable. Specifically, four ARGs were plasmid-derived, 18 ARGs were phage-derived and an additional six ARGs were predicted to be mobile, contributing to their mobility and potential spread between bacteria.

Restrictions on the use of antimicrobial compounds have led to a surge of interest in alternative solutions, such as natural, plant-based compounds. In our study, we investigated the efficacy of three feed supplements containing different additives, namely, probiotics (Lactobacillus spp., “Test substance A”), turmeric (Curcuma longa L., “Test substance B”), and fenugreek (Trigonella foenum graecum, “Test substance C”). In the experiment, we tested 180 birds of the Bábolna Tetra-SL laying hybrid breed that were infected with Salmonella enteritidis strains. The birds were randomly divided into six groups: three groups treated with the different additives, a negative control group, a positive control group, and an antibiotic-treated group using enrofloxacin. We examined the maturation and the time course of shedding of Salmonella; at the end of rearing, pathological and histopathological examinations were performed. When Salmonella was isolated from the cloacal swab samples, the enrofloxacin-treated group had a high number of animals shedding Salmonella by day 9, which was like the group treated with test material C. The greatest reduction in Salmonella shedding was observed in the groups treated with test materials A and B. In terms of pathological parameters, villus length and crypt depth were significantly better in the group treated with test material C compared to the positive and negative controls, and when comparing the body weight of the tested animals, the group treated with test material B had a significantly larger absorption surface area compared to the positive control group. Overall, the supplement with test material C proved to be the most effective. In the future, it is worthwhile to investigate the combination of the tested active substances for their possible synergistic effects and to perform a dose-response study to select the optimal dosage.

Background: The global spread of antimicrobial resistance (AMR) represents one of the most significant challenges of our generation. It is crucial to continuously monitor AMR, not only by investigating clinical, pathogenic strains but also by monitoring commensal bacterial strains, as they can serve as natural reservoirs of resistance. Infections caused by Enterococcus species are increasingly recognized as emerging threats to both animal and public health. Among economically important livestock, poultry as a major source of animal protein for humans is a frequent carrier of enterococci, and also of sporadically detected clinical disease. Methods: This study aimed to determine the antimicrobial susceptibility profile of Enterococcus strains (n = 499) isolated from chicken farms in Hungary. The minimum inhibitory concentration (MIC) was determined for 15 antibiotics, including 10 with established clinical breakpoints. Results: The strains exhibited good sensitivity to amoxicillin, one of the first-line treatments for Enterococcus infections in veterinary medicine, with only 20.8% showing resistance. However, we observed an alarming 27.9% resistance rate to vancomycin, which is reserved to treat infections caused by multidrug-resistant strains in humans. A comparison of our findings with Hungarian hospital records revealed that the resistance patterns of poultry-derived Enterococcus faecalis strains were very similar to those of human isolates, particularly regarding penicillins and aminoglycosides. Conclusions: Overall, the increasing rates of AMR reinforce the importance of conducting periodic studies to establish long-term trends. For multidrug-resistant strains, next-generation sequencing is recommended to elucidate the genetic basis of resistance.

Raw milk and dairy products can serve as potential vectors for transmissible bacterial, viral and protozoal diseases, alongside harboring antimicrobial-resistance genes. This study monitors the changes in the antimicrobial-resistance gene pool in raw milk and cheese, from farm to consumer, utilizing next-generation sequencing. Five parallel sampling runs were conducted to assess the resistance gene pool, as well as phage or plasmid carriage and potential mobility. In terms of taxonomic composition, in raw milk the Firmicutes phylum made up 41%, while the Proteobacteria phylum accounted for 58%. In fresh cheese, this ratio shifted to 93% Firmicutes and 7% Proteobacteria. In matured cheese, the composition was 79% Firmicutes and 21% Proteobacteria. In total, 112 antimicrobial-resistance genes were identified. While a notable reduction in the resistance gene pool was observed in the freshly made raw cheese compared to the raw milk samples, a significant growth in the resistance gene pool occurred after one month of maturation, surpassing the initial gene frequency. Notably, the presence of extended-spectrum beta-lactamase (ESBL) genes, such as OXA-662 (100% coverage, 99.3% identity) and OXA-309 (97.1% coverage, 96.2% identity), raised concerns; these genes have a major public health relevance. In total, nineteen such genes belonging to nine gene families (ACT, CMY, EC, ORN, OXA, OXY, PLA, RAHN, TER) have been identified. The largest number of resistance genes were identified against fluoroquinolone drugs, which determined efflux pumps predominantly. Our findings underscore the importance of monitoring gene pool variations throughout the product pathway and the potential for horizontal gene transfer in raw products. We advocate the adoption of a new approach to food safety investigations, incorporating next-generation sequencing techniques.

The waterfowl industry represents a narrow, yet economically significant, sector within the poultry industry. Although less prominent, the waterfowl sector is nonetheless of equal importance to any other livestock sector in terms of antimicrobial resistance and animal health issues. This study assesses the antimicrobial resistance profile of Pasteurella multocida bacterial strains isolated from clinical cases in Hungary’s duck and goose populations, determining the minimal inhibitory concentration (MIC) of 27 samples collected from 15 different locations. The results indicate that the isolated strains were susceptible to most antibiotics, except for notable resistance to enrofloxacin. These findings support that Pasteurella multocida largely retained its susceptibility. However, the observed resistance to enrofloxacin suggests overuse of fluoroquinolones, which indicates the potential need for stricter regulation of their use in the poultry industry.

Background: Widespread use of antibiotics has led to a global increase in resistance. The Escherichia coli bacterium is a facultative pathogen that often develops antibiotic resistance and is easily transmitted, not only in animal health but also in public health. Within the poultry sector, domestic fowl is widespread and one of the most dynamically growing sectors, which is why regular, extensive monitoring is crucial. Among economically important livestock, poultry as a major source of animal protein for humans is a frequent carrier of Escherichia coli, also with sporadically detected clinical disease. Methods: Our research evaluates the susceptibility of commensal Escherichia coli strains, isolated from large domestic fowl flocks in Hungary, to antibiotics of animal and public health importance, by determining the minimum inhibitory concentration value. Results: A total of 410 isolates were tested, with the highest level of resistance being found for florfenicol (62.7%). Particularly alarming are the resistance rates to enrofloxacin (52.9%), colistin (30.7%), and ceftriaxone (23.9%). We also found a resistance of 56.1% to amoxicillin and 22.2% to amoxicillin-clavulanic acid, which suggests that the majority of strains are β-lactamase-producing. When compared with the national human resistance data, we found with similar values for amoxicillin and amoxicillin-clavulanic acid, but the resistance rates of aminoglycosides, fluoroquinolones, and potency sulfonamide were worse in animal health. Conclusions: In conclusion, our results suggest that periodic surveys should be carried out and that long-term trends can be established that allow the monitoring of resistance patterns over time. For multidrug-resistant strains, new generation sequencing can be used to investigate the genetic background of resistance.