David John Hampson

Bovine viral diarrhea virus (BVDV) is globally endemic, with the ability to establish persistent infection (PI) being central to its complex epidemiology. Currently the genetic variability of BVDV in Bangladesh remains poorly understood. This study involved a survey in commercial dairy herds in the south-eastern part of Bangladesh in 2024/2025. A total of 373 blood samples were collected from cattle in 24 dairy herds. Serum and buffy coat samples were analyzed using antibody-ELISA and RT-qPCR targeting the 5′-UTR region, followed by sequencing. The MDBK cell line was used for virus isolation and biotyping. Herd and animal-level seroprevalences were 83.3% and 15.3%, respectively, while the corresponding viremic rates were 79.2% and 11.0%. Analysis of 41 sequences identified nine distinct BVDV-1 subgenotypes (1a, 1b, 1c, 1d, 1e, 1 k, 1p, 1o, and 1v), with BVDV-1b (41.5%) and BVDV-2a (14.6%) predominating. Additionally, five HoBiPeV-a pestiviruses were detected. Among antigen-positive cattle, 38 (92.68%) were identified as transiently infected and 3 (7.3%) were confirmed as PI. Six (14.6%) and 27 (65.9%) were identified as cytopathic and non-cytopathic biotypes, respectively. Risk factors for BVDV seropositivity included: female sex (OR: 3.0), clinical disease in the past three months (OR: 2.4), crowding (OR: 2.9), and lack of dedicated clothing for farm workers (OR: 5.7). Active infection was associated with calves (OR: 6.2), heifers (OR: 2.3), stunted growth (OR: 3.0), technician-performed artificial insemination (OR: 10.4), and frequent neighboring farm visits (OR: 3.1). This study has provided data crucial for formulating prevention and control strategies against BVDV to safeguard the Bangladeshi dairy industry.

Background and Aim: Methicillin-resistant coagulase-positive Staphylococci (MRCoPS), including methicillin-resistant Staphylococcus pseudintermedius (MRSP), methicillin-resistant Staphylococcus aureus (MRSA), and methicillin-resistant Staphylococcus coagulans (MRSC), are emerging zoonotic pathogens in veterinary hospitals, posing significant infection control challenges. This study aimed to investigate the molecular epidemiology, antimicrobial resistance profiles, and clonal dissemination of MRCoPS across environmental surfaces, veterinary personnel, and canine patients at the Veterinary Teaching Hospital, Chulalongkorn University (VTH-CU), Thailand.

Materials and Methods: A cross-sectional study was conducted involving 216 environmental samples, 23 veterinary staff, and 14 canine patients. Isolates were identified using biochemical tests, polymerase chain reaction (PCR), and matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry. Methicillin resistance was confirmed by mecA gene detection. Antimicrobial susceptibility was evaluated through disk diffusion following Clinical and Laboratory Standards Institute guidelines. Molecular typing was performed using staphylococcal cassette mec (SCCmec) PCR and pulsed-field gel electrophoresis (PFGE). Multivariate logistic regression identified environmental predictors of MRCoPS contamination.

Results: Among 88 coagulase-positive isolates, 62 (70.5%) were methicillin resistant, predominantly MRSP (91.9%), followed by MRSC (8.1%) and MRSA (1.6%). Floors represented the principal environmental reservoir, with significantly higher contamination odds than medical instruments (adjusted odds ratios [AOR] = 0.32; 95% confidence interval = 0.12–0.86; p = 0.024). The dermatological unit showed a six-fold higher risk of MRCoPS contamination than the medicine unit (AOR = 5.86; p = 0.027). All MRSC isolates carried SCCmec type V and displayed a consistent triple resistance pattern (gentamicin-clindamycin-erythromycin), while MRSP isolates exhibited diverse antibiograms and untypeable SCCmec elements. PFGE revealed clonal similarity (pattern A) between canine and environmental isolates, confirming the potential for nosocomial transmission.

Conclusion: MRCoPS, particularly MRSP, were widely distributed and persistent in the VTH-CU environment, despite routine cleaning. The clonal overlap among environmental and canine isolates highlights potential cross-contamination within the hospital. Strengthened disinfection protocols, antimicrobial stewardship programs, and regular environmental surveillance are imperative to mitigate the spread of multidrug-resistant staphylococci. This study highlights the importance of integrating environmental, animal, and human infection control practices in veterinary facilities within the context of One Health.

Salmonella Typhimurium (ST) is an important food-borne pathogen, particularly in chicken meat, making its rapid detection essential for food safety. Conventional detection methods are slow and equipment-intensive, creating the need for sensitive and portable alternatives. We developed a rapid, ultrasensitive, and portable electrochemical aptasensor platform for detecting ST in samples extracted from chicken meat. The sensor employed graphene oxide–bovine serum albumin (GO-BSA) nanocomposite to enhance electrode biocompatibility, stability, and aptamer immobilization. A specific NH2-modified DNA aptamer targeting ST allowed direct binding without prior extraction. Fabrication steps included GO-BSA drop-casting, aptamer immobilization, and BSA blocking before ST binding. The sensor operates on a signal-off mechanism, measured via differential pulse voltammetry (DPV), where the aptamer-ST complex formation reduces the redox signal of [Fe(CN)6]³-/4- due to insulation and electrostatic repulsion. The aptasensor demonstrated excellent sensitivity (limit of detection 3 CFU/mL) and high specificity. Performance validation using spiked samples extracted from chicken meat confirmed the effective detection of ST in a complex matrix, aligning with the results obtained through culture-based methods. The sensor also maintained good stability for up to 28 days at 4 °C. These results showed that aptasensors can be a rapid, cost-effective, and field-deployable tool for monitoring foodborne pathogens.

The increasing use of probiotics in livestock necessitates rigorous safety assessments to mitigate risks such as their inadvertent contribution to antimicrobial resistance (AMR) and horizontal gene transfer (HGT). This study employs whole-genome sequencing using both long-read (GridION, Oxford Nanopore Technologies) and short-read (Illumina, San Diego, CA, USA) platforms to assess the genomic and plasmidome profiles of five Thai strains of Pediococcus acidilactici, that previously have been evaluated for probiotic potential in livestock. Our comprehensive analysis identified genes encoding AMR, virulence factors, and probiotic-related genes. Notably, strains AF2519 and AF2019 harbored plasmid-borne tet(M) and erm(B) genes, with tet(M) embedded in a novel composite genetic arrangement flanked by mobile elements, suggesting historical recombination and altered mobility potential. Strains IAF6519, IAF5919, and P72N, free from plasmid-borne AMR genes, emerged as safer candidates, lacking virulence genes. Phenotypic tests revealed discrepancies with genomic data; for instance, AF2019 was resistant to clindamycin without detectable genes, and showed susceptibility to tetracycline despite the presence of tet(M). The absence of complete transfer machinery in AF2519 and AF2019 suggests a reduced HGT risk. These findings underscore the importance of integrating genomic and phenotypic approaches in probiotic safety evaluations. The presence of plasmid-borne AMR genes in certain strains advises caution in their use, impacting probiotic selection and regulatory compliance in agriculture. This research informs policies and best practices for safe probiotic deployment, ensuring both efficacy and safety.

Background and Aim: Industrial-scale probiotic production requires economically viable media formulations that do not compromise strain functionality. This study aimed to develop a cost-effective medium for cultivating Lactiplantibacillus plantarum 22F (L22F), a probiotic candidate isolated from swine feces, while evaluating its industrial viability and functional metabolic profile.

Materials and Methods: Carbon (glucose, sucrose, and dextrose) and nitrogen (yeast extract, soy protein isolate, and whey protein concentrate) sources were screened using one-variable-at-a-time and Plackett–Burman design, followed by Response Surface Methodology for optimization. Fermentation was scaled from a flask to 50 L fermenters at 37 °C and pH 6.50 ± 0.05. Cell viability, pH, and residual sugar were monitored. Functional assessments included stress tolerance assays (heat, acid, bile, and oxidative stress) and untargeted metabolomic profiling using ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry.

Results: The optimal medium comprised 9 g/L glucose, 14.1 g/L soy protein isolate, and 14.1 g/L yeast extract, supplemented with minerals. In 50 L fermentation, L22F achieved 9.20 log colony-forming units/mL at 12 h, with residual sugar at 1.50 g/L and pH 3.99. Compared to de Man, Rogosa, and Sharpe, the modified medium reduced production cost by 70%–88%, improved fermentation efficiency, and supported enhanced stress resilience. Metabolomic analysis revealed an elevated production of bioactive metabolites, particularly 1,4-dihydroxy-2-naphthoic acid and indolelactic acid, which are known to support gut homeostasis, anti-inflammatory responses, and probiotic efficacy.

Conclusion: This study presents a cost-effective and scalable fermentation medium specifically designed for high-density L22F production. Beyond economic advantages, the medium enhanced the functional properties of L22F, supporting its application as a sustainable probiotic feed additive for swine. These findings establish a foundation for further industrial application and in vivo validation.

Keywords: cost-effective production, fermentation optimization, Lactiplantibacillus plantarum 22F, metabolomics, modified medium, stress tolerance, swine probiotic.

Escherichia coli recovered from dogs with clinical conditions such as urinary tract infections are often used to assess populations for resistance to critically important antimicrobials (CIAs). Despite the potential importance of such strains, the number of organisms scrutinised is very small and no information is obtained from the preponderance of normal, healthy dogs. Commensal E. coli are a valuable alternative, but little is gained if the number of isolates also remains small. In this work we demonstrate novel technology reliant on laboratory robots to examine the CIA resistance status of millions of commensal E. coli in the faeces of 86 healthy companion dogs. Fluoroquinolone-resistant isolates also underwent phenotypic resistance testing to detect multi-class resistant strains, and multi-locus sequence types and antimicrobial resistance genes identified with whole genome sequencing. Ciprofloxacin resistance was detected in isolates from five (5.8 %) of the healthy dogs, with a high ratio of ciprofloxacin-resistant E. coli to total E. coli being found in three of these animals. Antimicrobial susceptibility testing of the five isolates identified four resistance profiles, with all isolates having multi-class phenotypic resistance to between three and six antimicrobial classes. Genomic analysis confirmed the presence of genes encoding multi-class resistance, with four isolates being resistant to multiple classes. The five isolates belonged to sequence types ST1193 (n = 3) and ST354 (n = 2). All five isolates possessed multiple mutations within the quinolone resistance-determining regions. The predominant sequence type ST1193 is an emerging multidrug resistant E. coli strain harbouring fluoroquinolone resistance, which previously primarily has been detected in clinical samples from dogs. The current study demonstrates the power of robotics for delivering a multi-staged approach based on mass screening to achieve sensitivity and specificity achieved with detailed phenotypic and genotypic characterisation. Based on this experience, future studies can be expanded to yield a much richer understanding of antimicrobial resistance in canines.

The ongoing increase in antimicrobial resistance (AMR) in Escherichia coli, particularly the emergence of extended-spectrum beta-lactamase (ESBL)-producing and colistin-resistant strains in livestock, is a significant public health concern. The effectiveness of pig abattoir management, specifically through Hazard Analysis and Critical Control Points (HACCP) protocols, in reducing antimicrobial-resistant contamination continues to be scrutinized. This study investigated the prevalence, characteristics, and critical contamination points of ESBL-producing E. coli (ESBL-Ec) and colistin-resistant ESBL-Ec across the slaughtering processes in two pig abattoirs in Thailand-one operating under HACCP standards and the other certified solely under Good Manufacturing Practices. A higher prevalence of ESBL-Ec was found in the non-HACCP facility (67.98%) compared with the HACCP facility (52.04%), especially in pig carcasses. Skin and carcass washing in HACCP facilities effectively decreased bacterial contamination. Conversely, non-HACCP facilities should implement measures such as cleaning skin with disinfectants at the lairage, regularly monitoring and adjusting the final washing protocol, and strict sterilization of chopping plates to effectively control contamination points. Most ESBL-Ec isolates were multidrug-resistant and carried blaCTX-M group 1 or group 9 genes. Additionally, 12.6% of these isolates were resistant to colistin, with the mcr-1 gene predominantly identified. ST10 was the dominant clone of mcr-carrying ESBL-Ec across various slaughtering stages and sample types. These findings highlight the importance of implementing HACCP protocols to reduce contamination, enhance food safety, and mitigate public health risks. Ongoing AMR monitoring to find critical points along the slaughtering process is essential to reduce sources of AMR transmission to consumers.

This study aimed to achieve industrial-scale production of the Thai native swine-derived probiotic strain Pediococcus acidilactici 72 N (P72N) using a cost-effective, food-grade modified medium, and to assess the efficacy of this medium by evaluating the probiotic’s functional characteristics and metabolomic profile. Conventional and statistical optimization techniques were used to screen food-grade carbon sources (glucose, dextrose, sucrose) and nitrogen sources (beef extract, yeast extract, sweet whey) to develop the optimal formulation. The final medium contained 10 g/L dextrose, 45 g/L yeast extract, 5 g/L sodium acetate, 2 g/L ammonium citrate, 2 g/L di-potassium hydrogen phosphate, 1 g/L Tween 80, 0.1 g/L magnesium sulfate, and 0.05 g/L manganese sulfate. This formulation achieved significantly higher viable cell counts compared to commercial MRS medium. Scale-up fermentation in 5 L and 50 L fermenters under controlled conditions (37 °C, pH 6.5, 120 rpm) yielded viable cell counts exceeding 9.60 log CFU/mL within 12 h, reducing production costs by 67–86%. P72N in the modified medium demonstrated improved tolerance to environmental stresses. Metabolomic analysis revealed that P72N produced a variety of bioactive metabolites, particularly 1,4-dihydroxy-2-naphthoic acid (1,4-DHNA) and indolelactic acid (ILA) which were detected in higher levels in the modified medium, demonstrating its suitability for industrial production of P72N as a potential feed additive for swine farming.

The increasing resistance of bacteria to antimicrobials is a major threat to public health. This study investigates the prevalence of antimicrobial resistance, both phenotypic and genotypic, among Campylobacter isolates from Australian meat chickens in 2022, as a follow up to investigate trends since the last national surveillance undertaken in 2016. Isolates (n = 186) were obtained at slaughter from 200 pooled cecal samples taken from 1,000 meat chickens. The majority of C. jejuni (68.7%) and C. coli (88.9%) isolates were susceptible to all the antibiotics that were tested, and no multi-drug resistance was found. Resistance to ciprofloxacin (fluoroquinolone) was detected in 24.4% of the C. jejuni and 3.2% of the C. coli isolates. Whole genome sequencing revealed a diverse range of sequence types (STs). These included 32 previously reported STs for C. jejuni and 13 for C. coli, as well as four and seven previously undescribed STs for each species, respectively. The STs containing fluoroquinolone-resistant isolates were ST2083, ST10130, ST2895, ST7323, ST2398, and ST1078 for C. jejuni, and ST860 and ST894 for C. coli. Although fluoroquinolones are not used in animal production in Australia, resistance amongst C. jejuni isolates was high (24.4%). This finding emphasizes the need for enhanced surveillance and regular sampling along the food chain to understand the source of the isolates and to mitigate risks of antimicrobial resistance to protect public health.

Salmonella is a major cause of global gastroenteritis, with pig-based products being significant sources. The Hazard Analysis Critical Control Points (HACCP) standard ensures food safety by identifying Salmonella contamination dynamics and improving control strategies. A study in Thailand found that pork in HACCP-certified slaughterhouses had significantly reduced Salmonella contamination and antimicrobial resistance (AMR) compared to in non-HACCP facilities. However, both types of slaughterhouses still experience Salmonella contamination during the slaughtering process, with limited information available on contamination sources and critical steps. The current study compared Salmonella distribution and AMR profiles in two Thai pig slaughterhouses, one of which implemented HACCP. A total of 570 samples, including feces, carcass swabs, and environmental samples, were cultured for Salmonella and investigated for AMR. The overall prevalence was 24.7%, being significantly lower at the HACCP-compliant slaughterhouse 1 (S1, 13.7%) compared to the non-compliant slaughterhouse 2 (S2, 41.2%) (P = 0.03). Slaughterhouse-specific Salmonella prevalence varied across slaughtering steps, with S2 showing high contamination rates in carcasses post-final washing, persisting until post-cutting. Additionally, specific strains were found in various locations, including feces, carcasses, workers' hands, cutting boards, and knives before and during operations. Conversely, carcasses post-final washing in S1 had the lowest contamination. Real-Time PCR identified higher Salmonella contamination and a greater copy number in S2-cutting carcasses compared to in S1. Overall, 42.6% of isolates were multidrug-resistant, showing strong resistance to ampicillin and tetracycline, while 8.51% produced extended-spectrum beta-lactamase (ESBL). It is evident that continuous monitoring and control measures are crucial to mitigate contamination and antibiotic resistance in foodborne pathogens such as Salmonella. The current study confirms that adherence to HACCP in slaughterhouses significantly reduces Salmonella in pork products. However, contamination levels rose notably post-cutting in both HACCP and non-HACCP facilities, with equipment, other carcasses, and workers' hands acting as sources of contamination. Rigorous monitoring during cutting processes is essential to identify and mitigate contamination sources, thereby improving food safety in meat processing facilities.