Building an International One Health Strain Level Database to Characterise the Epidemiology of AMR Threats: ESBL—AmpC Producing E. coli as An Example—Challenges and Perspectives

Design, Synthesis, Antimicrobial Properties, and Molecular Docking of Novel Furan-Derived Chalcones and Their 3,5-Diaryl-∆2-pyrazoline Derivatives

The present work focuses on the synthesis and preliminary structure activity relationships (SARs) of furan-derived chalcones and their corresponding ∆2-pyrazoline derivatives as antimicrobial agents. Eight novel chalcone derivatives and eight ∆2-pyrazoline compounds were synthesized in moderate to good isolated yields. The target compounds were evaluated as antimicrobial agents against two Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis), two Gram-negative (Escherichia coli and Klebsiella pneumoniae), and fungi (Candida albicans) species. Based on the SARs, chalcones 2a and 2h showed inhibition activity on all tested microbial species, while ∆2-pyrazoline 3d was found to be selective for some microbial species. The most potent compounds (2a, 2h, and 3d) were docked into glucosamine-6-phosphate synthase (GlcN-6-P), the molecular target enzyme for antimicrobial agents, utilizing the Autodock 4.2 program, in order to study their virtual affinity and binding mode with the target enzyme. The selected potent compounds were found to bind to the active site of the enzyme probably in a similar way to that of the substrate as suggested by the docking study. In summary, the newly developed furan-derived chalcones and their ∆2-pyrazoline derivatives could serve as potent leads toward the development of novel antimicrobial agents.

Detection and Phylogenetic Analysis of Extended-Spectrum β-Lactamase (ESBL)-Genetic Determinants in Gram-Negative Fecal-Microbiota of Wild Birds and Chicken Originated at Trimmu Barrage

Extended-spectrum β-lactamases (ESBL) give rise to resistance against penicillin and cephalosporin antibiotics in multiple bacterial species. The present study was conducted to map genetic determinants and related attributes of ESBL-producing bacteria in three wild aquatic bird species and chickens at the "Trimmu Barrage" in district Jhang, Punjab province, Pakistan. To study the prevalence of ESBL-producing bacteria, a total of 280 representative samples were collected from wild bird species; cattle egrets (Bubulcus ibis), little egrets (Egretta garzetta) and common teals (Anas crecca) as well as from indigenous chickens (Gallus gallus domesticus) originating from a local wet market. The isolates were confirmed as ESBL producers using a double disc synergy test (DDST) and bacterial species were identified using API-20E and 20NE strips. A polymerase chain reaction (PCR) was used to detect ESBL genetic determinants and for genus identification via 16S rRNA gene amplification. A phenotypic antimicrobial susceptibility test was performed for ESBL-producing isolates against 12 clinically relevant antibiotics using the Kirby-Bauer disk diffusion susceptibility test. A phylogenetic tree was constructed for the sequence data obtained in this study and comparative sequence data obtained from GenBank. The overall prevalence of ESBL-producing bacteria was 34.64% (97/280). The highest percentage (44.28%; 31/70) of ESBL-producing bacteria was recovered from chickens (Gallus gallus domesticus), followed by little egrets (Egretta garzetta) (41.43%; 29/70), common teal (Anas crecca) (28.57%; 20/70) and cattle egrets (Bubulcus ibis) (24.28%; 17/70). Five different ESBL-producing bacteria were identified biochemically and confirmed via 16S rRNA gene sequencing, which included Escherichia coli (72; 74.23%), Enterobacter cloacae (11; 11.34%), Klebsiella pneumoniae (8; 8.25%), Salmonella enterica (4; 4.12%) and Pseudomonas aeruginosa (2; 2.06%). Based on PCR, the frequency of obtained ESBL genes in 97 isolates was blaCTX-M (51.55%), blaTEM (20.62%), blaOXA (6.18%) and blaSHV (2.06%). In addition, gene combinations blaCTX-M + blaTEM, blaTEM + blaOXA and blaCTX-M + blaSHV were also detected in 16.49%, 2.06% and 1.03% of isolates, respectively. The ESBL gene variation was significant (p = 0.02) in different bacterial species while non-significant in relation to different bird species (p = 0.85). Phylogenetic analysis of amino acid sequence data confirmed the existence of CTX-M-15 and TEM betalactamases. The average susceptibility of the antibiotics panel used was lowest for both Klebsiella pneumoniae (62.5% ± 24.42) and Salmonella enterica (62.5% ± 31.08) as compared to Enterobacter cloacae (65.90% ± 21.62), Pseudomonas aeruginosa (70.83% ± 33.42) and Escherichia coli (73.83% ± 26.19). This study provides insight into the role of aquatic wild birds as reservoirs of ESBL-producing bacteria at Trimmu Barrage, Punjab, Pakistan. Hence, active bio-surveillance and environment preservation actions are necessitated to curb antimicrobial resistance.

Antimicrobial resistance and its relationship with antimicrobial use on Austrian dairy farms

The aim of this study was to investigate the prevalence of ESBL/AmpC-producing E. coli and the resistance pattern of commensal E. coli, as well as the link between the use of antibiotics (AMU) and the occurrence of resistance in E. coli on Austrian dairy farms. AMU data from 51 farms were collected over a one-year period in 2020. Fecal samples were collected from cows, pre-weaned and weaned calves in 2020 and 2022. Samples were then analyzed using non-selective and selective agar plates, E. coli isolates were confirmed by MALDI-TOF analysis. Broth microdilution was used for antimicrobial susceptibility testing. The AMU of each farm was quantified as the number of Defined Daily Doses (nDDDvet) and Defined Course Doses (nDCDvet) per cow and year. Cephalosporins (mean 1.049; median 0.732 DDDvet/cow/year) and penicillins (mean 0.667; median 0.383 DDDvet/cow/year) were the most frequently used antibiotics on these farms, followed by tetracyclines (mean 0.275; median 0.084 DDDvet/cow/year). In 2020, 26.8% of the E. coli isolated were resistant to at least one antibiotic class and 17.7% of the isolates were classified as multidrug resistant (≥3 antibiotic classes). Out of 198 E. coli isolates, 7.6% were identified as extended-spectrum/AmpC beta-lactamase (ESBL/AmpC) producing E. coli. In 2022, 33.7% of E. coli isolates showed resistance to at least one antibiotic and 20.0% of isolates displayed multidrug resistance. Furthermore, 29.5% of the samples carried ESBL/AmpC-producing E. coli. In 2020 and 2022, the most frequently determined antibiotic resistances among commensal E. coli isolates were to tetracyclines, sulfonamides and penicillins. In addition, pre-weaned calves had the highest resistance rates in both years. Statistical analyses showed a significant association between low and high use AMU classifications for penicillins (in nDDDvet/cow/year) and their respective resistance among commensal E. coli isolates in 2020 (p = 0.044), as well as for sulfonamide/trimethoprim (p = 0.010) and tetracyclines (p = 0.042). A trend was also noted between the total amount of antibiotics used on farm in 2020 (by nDDDvet/cow/year) and multidrug resistances in commensal E. coli isolated on farm that year (p = 0.067). In conclusion, the relationship between AMU and antimicrobial resistance (AMR) on dairy farms continues to be complex and difficult to quantify.