Search Results (153)

Staphylococcus aureus frequently causes intramammary infections in dairy cows (bovine mastitis), which impair animal welfare, milk yield, and food safety. This study determined the prevalence and genetic diversity of S. aureus in bulk tank milk (BTM) samples from community-based Alpine dairy pastures in Tyrol, a major milk-producing region in Austria. Throughout the 2023 Alpine season (May–September), 60.3% (94/156) of BTM samples tested positive for S. aureus at least once over the course of up to four samplings. A total of 140 isolates collected from the 94 S. aureus-positive community-based Alpine dairy pastures revealed 33 distinct spa types, with t2953 (n = 33), t529 (n = 12), t267 (n = 11), and t024 (n = 10) being the most common. Selected isolates representing the different spa types were characterised by DNA microarray-based genotyping, multi-locus sequence typing (MLST), and antimicrobial susceptibility testing. Isolates with spa types associated with bovine-adapted CC8 (CC8bov/GTB) were identified as the most common subtype, being detected in BTM samples from 35.3% (55/156) of the pastures. This emphasises the high prevalence of this subtype in dairy herds across European Alpine countries. Other common bovine-associated subtypes were also detected, including CC97, CC151, and CC479. While antimicrobial resistance was rare, enterotoxin-producing genes were detected in all CC8bov-associated spa types. Overall, these findings underscore the importance of rigorous hygiene practices in dairy farming, particularly in community-based Alpine dairy pastures, where the risk of transmission is particularly high. It also emphasises the need for continued surveillance and subtyping to improve animal health, ensure food safety, and promote sustainable milk production. Full article

Subclinical mastitis (SCM) is a stealthy but devastating challenge in the dairy industry, leading to economic losses and hindering efforts to achieve milk self-sufficiency. This study investigated the prevalence of SCM, antimicrobial resistance, and virulence profiles of Escherichia coli. A total of 174 milk samples were analyzed using the California mastitis test (CMT), somatic cell counts (SCCs), bacteriological culture, MALDI-TOF MS, and polymerase chain reaction (PCR). The findings revealed that the SCM prevalence was 68/174 (39.08%) based on CMT and SCC. Among SCM-positive samples, 60/68 (88.23%) were identified as E. coli, confirmed by MALDI-TOF MS and PCR assay. The most frequently detected serogroups were 0113 (11.6%) and 0113 (3.3%). Additionally, the genes for Stx1 and Stx2 were also detected in nine (15%) and one (1.7%), respectively. Antimicrobial susceptibility tests showed widespread resistance, with E. coli isolates demonstrating resistance to penicillin in 43 (71.6%), followed by ciprofloxacin in 42 (70%) and gentamicin in 18 (30%). A larger proportion of the E. coli strains (100%) harbored the bla_VIM gene, while 23 (38.3%), 20%, 20%, and 1.47% contained bla_KPC, bla_NMD, suli1, and msrA. Thirty (50%) isolates were considered multidrug-resistant (MDR). These findings underscore the urgent need for enhanced surveillance and antibiotic stewardship in dairy farming. The presence of MDR E. coli in SCM poses a dual threat of potential transmission to humans and treatment failures in mastitis management. This study highlights the importance of proactive control strategies to mitigate the spread of antimicrobial resistance in livestock and beyond. Full article

Staphylococcus aureus (S. aureus) is a major pathogen responsible for mastitis in dairy cows and can contaminate raw milk, thereby posing significant health risks to consumers. The emergence of methicillin-resistant S. aureus (MRSA) has further heightened public health concerns due to its antibiotic resistance and infectious potential. In this study, we examined the prevalence, virulence genes, antimicrobial resistance, spa types, and biofilm formation of S. aureus isolates from dairy farms in Guangxi Province, China. Among 242 randomly selected samples, 37 S. aureus strains were identified (15.3% infection rate), including 67.5% MRSA. Antibiotic resistance was observed in 78.4% of isolates, with 35.1% exhibiting multidrug resistance (MDR). Enterotoxin gene analysis showed sea as the most common (67.6%), followed by ser (54.1%) and seh (51.4%), whereas seb and selj were absent. All isolates formed biofilms in vitro, with 64.8% showing strong biofilm-forming ability. Staphylococcal protein A (spa) typing classified the 37 S. aureus strains into 11 spa types, with t030 being the most prevalent (43.2%). These findings indicate that S. aureus is moderately prevalent in raw milk, often carrying multiple virulence genes, forming robust biofilms, and showing antimicrobial resistance. The MRSA that is “latent” in raw milk reminds us of the need for monitoring at the farm level. Full article

Bovine mastitis is a significant disease affecting dairy cattle worldwide, impacting milk quality and farm profitability. Understanding pathogen distribution is crucial for effective disease management. This study analyzed 319,634 individual cow milk samples submitted to the UC Davis Milk Quality Laboratory between 2009 and 2023 to assess pathogen prevalence, seasonal variations, and long-term trends. Routine microbiological cultures identified major and minor mastitis pathogens, with additional testing for Mycoplasma spp. Statistical analyses evaluated annual and seasonal trends in bacterial isolation rates. Results indicated that environmental pathogens, particularly non-aureus staphylococci and coliforms, were most frequently isolated, while contagious pathogens (Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp.) were less prevalent. Seasonal trends revealed higher contamination rates in Winter and increased no-growth samples in Summer. The study also observed a decline in sample submissions in recent years, possibly reflecting evolving dairy management practices. These findings provide a comprehensive perspective on mastitis pathogen dynamics in California’s Central Valley, supporting improved milk quality control measures and tailored mastitis prevention strategies. Full article

The increasing prevalence of bacterial resistance to conventional disinfectants and antibiotics has intensified the search for effective, natural alternatives in the dairy industry. This study evaluates the bactericidal efficacy of Punica granatum L. (pomegranate) peel ethanolic extract, focusing on its application in pre- and post-dipping procedures for mastitis prevention. The extract exhibited potent activity against Escherichia coli and Staphylococcus aureus, two major mastitis pathogens. At a concentration of 10 mg/mL, the extract induced significant membrane disruption within 30 s of exposure, as evidenced by propidium iodide uptake and elevated extracellular DNA levels (Escherichia coli: 64.25 ng/μL; Staphylococcus aureus: 83.25 ng/μL) compared to controls (11.20 ng/μL and 35.20 ng/μL, respectively; p < 0.05). Complete growth inhibition (100%) was achieved within 30 s at 25 and 50 mg/mL, matching the efficacy of commercial chlorhexidine and high-concentration hypochlorite. Phytochemical analysis identified punicalagin as the predominant bioactive compound. These findings establish Punica granatum peel extract as a fast-acting bactericidal agent, exhibiting an efficacy comparable to or exceeding that of conventional disinfectants. Its rapid action and plant-based origin highlight its potential as a viable alternative for the prevention and control of bovine mastitis in dairy farming. Full article

This study assessed the impact of farming systems on aflatoxin M1 (AFM1) content and the prevalence of mastitis-causing bacteria in goat milk. A total of 233 milk samples were collected from two Skopelos goat farms—one intensive and one extensive farm—and analyzed for AFM1 content using a competitive ELISA. An additional 219 samples from goats suspected of subclinical mastitis were tested for bacterial prevalence with microbial culturing. The results showed that AFM1 concentration was significantly higher in the intensive farming system (7.76 ± 0.76 ng/kg) than in the extensive farming system (3.78 ± 0.79 ng/kg), though it remained below the legal limit of 50 ng/kg. The main effects of season and year were not significant, though higher levels of AFM1 were observed during winter. The interaction effects of season–farming system and year–season–farming system on AFM1 levels were significant. The prevalence of mastitis-causing bacteria varied by system, with Streptococcus spp. being more common in the extensive farming system, and Staphylococcus aureus was more frequently detected in milk samples from the intensive farming system. Binomial regression indicated that both the farming system and lactation stage significantly influenced Streptococcus spp. prevalence (p = 0.05; OR = 1.9 and 2.7, respectively). It is concluded that the farming system affects those quality parameters in goat milk. Full article

The dairy industry relies on the health and well-being of dairy cows for the optimal production of milk and dairy products. Mastitis, a prevalent and economically burdensome disease characterized by udder inflammation, poses significant challenges to dairy farmers worldwide. In this study, we employed peptidomics to explore the peptide profiles of dry secretions collected from dairy cows at specific intervals during the dry-off period. We hypothesized that alterations in peptide composition during the dry period may influence pathogen proliferation and immune cell functioning, thereby impacting mastitis susceptibility. Our objectives were to investigate the following: (i) differences in peptide composition and alterations between healthy cows and those with subclinical mastitis, potentially serving as biomarkers for early mastitis detection and offering insights into udder bioprocesses; (ii) variations in peptide profiles between the early (day 2) and later (day 21) stages of the dry-off period during both health conditions. Dry secretions were collected from 16 udder quarters of 8 cows at two defined time points—Day 2 (D2) and Day 21 (D21)—during the dry period. Our results revealed distinct peptide patterns between healthy and subclinical mastitis cows, as well as temporal variations in peptide profiles throughout the dry-off period. A total of 1235 peptides, originating from 59 distinct proteins (primarily β-casein), were detected across the four groups: subclinical mastitis day 21 (SCM-D21), subclinical mastitis day 2 (SCM-D2), healthy day 21 (H-D21), and healthy day 2 (H-D2). Furthermore, 56 out of the 1235 peptides identified in total matched known functional peptides, with a total of 17 different functions including antimicrobial, antioxidant, and immunomodulatory, suggesting their potential roles in mastitis pathogenesis and mammary gland physiology. Comparative analyses revealed changes in the levels of these functional peptides across the four different groups, suggesting their potential roles in regulating immune responses, oxidative stress, inflammatory processes, and other biological activities during subclinical mastitis and the dry-off period. These findings provide valuable insights into mastitis detection, management strategies, and dairy cow health monitoring, offering promising avenues for enhancing milk quality and dairy industry sustainability. Full article

Mastitis is a major infectious disease that causes significant economic losses in the dairy industry. Current control programs primarily rely on antimicrobials, contributing to the growing concerns of the resistance situation and drug residues in milk. This study aimed to identify the bacterial pathogens responsible for subclinical/clinical bovine mastitis, assess their antimicrobial resistance profiles, and evaluate the antimicrobial effects of Caesalpinia sappan in treating mastitis through both in vitro and in vivo studies. A total of 138 bacterial isolates, representing 40 species, were identified from 100 milk samples collected from dairy cows under the Maejo Cooperative Group in Chiang Mai, Thailand, between May 2021 and February 2022. The most prevalent species was Escherichia coli (10.87%), followed by Bacillus cereus (9.42%) and Staphylococcus sciuri (7.97%). The highest resistance rates were observed for penicillin (65.21%), followed by streptomycin and lincomycin (61.59%). Nine isolates resisted all 18 antimicrobials tested. The average minimum inhibitory concentration (MIC) of C. sappan against the identified pathogens ranged from 0.63 to 17.68 mg/mL, with the highest MIC observed against Pseudomonas luteola. In the animal experiment, treatment with a prototype of an intramammary infusion compound primarily formulated from C. sappan significantly reduced the total bacterial count and California Mastitis Test (CMT) scores (p < 0.01). These results suggest that C. sappan exhibits antimicrobial efficacy against various mastitis bacteria and could serve as a potential alternative treatment to control bovine mastitis in dairy cattle within the study region. Full article

The objective of the study was to ascertain the potential of infrared thermal imaging (IRT) to detect the development of clinical mastitis at an early stage. The study was carried out on a one-site small pig farm with 80 breeding sows (crossbreed Landrace × Yorkshire) that had a history of high incidence of MMA. The udder-skin temperatures of the breeding sows were measured using a high-quality IRT camera (FLIR T650sc), in accordance with the IRT measurement protocol (including calibration and corrections), with a measurement uncertainty of $\pm 0.5$$°\mathrm{C}$. This study improves upon previous research by refining the measurement protocol and selecting more appropriate statistical methods to better analyze time-dependent data. To minimise the impact of measurement uncertainty, we propose the use of time-dependent trends (simple moving averages) caused by farrowing and lactation in place of the original IRT time series data. The findings indicate that a significant disparity between the maximum and minimum daily udder-skin temperature values, along with a pronounced maximal median of daily udder-skin IRT temperature values in sows during the early post-farrowing period, is associated with an elevated prevalence of multiglandular mastitis. Consequently, the utilisation of IRT imaging of the udder skin has the potential to facilitate the detection or prediction of multiglandular mastitis in sows. However, identifying uniglandular mastitis in individual mammary glands is more complex and may rely on time-dependent statistical trends derived from IRT imaging. Full article

Mastitis, a prevalent inflammatory disease in mammals, disrupts mammary gland function, compromises milk quality, and can contribute to increased offspring morbidity and mortality. Maintaining the health of porcine mammary epithelial cells (PMECs), the primary cell type in the mammary gland, is crucial for minimizing the adverse effects of this disease. Selenium yeast (SeY), an organic selenium compound known for its antioxidant and immune-enhancing properties, has yet to be fully understood in its role in modulating inflammation in mammary gland. In this study, lipopolysaccharide (LPS) (50 µg/mL, 24 h) significantly upregulated the expression of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), and interleukin-1β (IL-1β) (p < 0.05). Pretreatment with 1 µM SeY significantly attenuated the LPS-induced inflammatory response by reducing the levels of TNF-α, IL-6, IL-8, and IL-1β (p < 0.05). Additionally, SeY enhanced cellular antioxidant defenses by increasing total antioxidant capacity (T-AOC), superoxide dismutase (SOD) activity, glutathione (GSH) levels, and glutathione peroxidase (GSH-Px) activity, while concurrently decreasing malondialdehyde (MDA) accumulation (p < 0.05). SeY also restored both intracellular and extracellular triglyceride levels and rescued lipid droplet formation, which were disrupted by LPS treatment. Furthermore, SeY upregulated key regulators involved in milk synthesis (p < 0.05). These findings suggest that SeY effectively mitigates LPS-induced inflammation and oxidative stress while preserving critical pathways for milk fat and protein synthesis in PMECs. Full article

This study compared two types of automatic milking systems (AMSs) and their relationship with epidemiological indices of subclinical mastitis (SCM) and prevalence of mastitis-causing pathogens. Conducted between 2020 and 2023 on a dairy farm in Vacaria, Rio Grande do Sul, Brazil, this study analyzed data from 464 lactating cows housed in compost-bedded pack barns (CBPBs) and milked by eight AMS units: four from DeLaval (which utilizes teat cup for teat cleaning) and four from Lely (which utilizes brushes for teat cleaning). SCM incidence, prevalence, percentage of chronic, and cured cows were determined using somatic cell counts (SCCs) and microbiological cultures. Statistical analyses included the Wilcoxon signed-rank test and Chi-square test to evaluate SCM indices and pathogen associations with AMSs. No significant difference was observed in SCM prevalence (p = 0.3371), percentage of chronic (p = 0.3590) and cured cows (p = 0.4038), SCC (p = 0.1290), and total bacterial count (TBC) (p = 0.8750) between AMS types. However, the SCM incidence was higher in the Lely (14.7%) than in the DeLaval AMS (9.1%) (p = 0.0032). The Chi-square results revealed that the Lely AMS was associated with major pathogens like Staphylococcus aureus and Escherichia coli, whereas DeLaval showed associations with minor environmental and contagious pathogens, particularly non-aureus Staphylococci. The findings indicate a relationship between AMS-cleaning systems and pathogen spread, suggesting that Lely AMS may contribute to more aggressive infections due to its cleaning system. Full article

In this study, we sought to evaluate the prevalence of bacterial pathogens of mastitis in dairy cattle in the Inner Mongolia Autonomous Region, China. The study was conducted from 2015 to 2024 using a total of 12,053 clinical mastitis (CM) and sub-clinical mastitis (SCM) samples. The pathogens were isolated and identified by standard bacteriological and mycological methods. The most common pathogens isolated were Escherichia coli (13.82%), Staphylococcus aureus (10.28%), Klebsiella spp. (8.96%), Streptococcus agalactiae (7.45%), Streptococcus uberis (6.60%), coagulase-negative staphylococci (5.84%), and Streptococcus dysgalactiae (4.21%). From 2015 to 2017, the primary pathogens responsible for causing mastitis in cows were Staphylococcus aureus and Streptococcus agalactiae. In 2018, the most frequently isolated pathogen was Staphylococcus aureus. Notably, the isolation rate of Escherichia coli increased from 12.31% to 21.72%, and the isolation rate of Klebsiella spp. increased from 7.52% to 14.01% from 2019–2024. Mycoplasma was only detected in clinical mastitis cases, with a separation rate as high as 6.95%. In summary, the isolation rate of environmental pathogens is gradually increasing, while that of contagious pathogens has been continuously declining. This indicates that the current prevention strategies for infectious pathogens are effective. As a next step, it will be important to develop new strategies specifically targeting environmental pathogenic microorganisms. Full article

Background: Staphylococcus aureus is one of the most prevalent pathogens causing mastitis in dairy animals and represents a serious issue of public health concern due to its resistance against multiple antimicrobials. Objectives: This study assessed 101 S. aureus isolates obtained from quarter milk of animals with subclinical mastitis in the Ragusa area (Sicily, Italy). Methods: Antibiotic resistance against nine antibiotics was evaluated using the Kirby–Bauer method, and the Minimum Inhibitory Concentration (MIC) values were measured for oxacillin (OXA) and vancomycin (VA). Additionally, the isolates were genetically characterized through multiplex PCR to identify the presence of spa, mecA, mecC, pvl, vanA, vanB, and vanC genes, along with pulsed-field gel electrophoresis analysis and multi-locus sequence typing (MLST). Results: The highest rates of antibiotic resistance were found against gentamicin (47.5%) and erythromycin (29.7%), with 86.1% of strains exhibiting resistance to at least two antimicrobials and 33.7% showing resistance to three antimicrobial classes. Furthermore, the results indicated that the presence of antibiotic resistance genes was not correlated with phenotypic resistance, and a phylogenetic analysis revealed varying phenotypic resistance profiles even within the same PFGE cluster. Lastly, alongside a new allelic profile ST 9471, MLST analysis identified five additional STs clustered into three CCs, with CC5 originating from human ancestral strains through human-to-animal host transfers, making it the dominant group. Conclusions: This study provided valuable insights into regional trends, allowing for the identification of significant antibiotic-resistant patterns and offering an understanding of bacterial dynamics in these environments, underscoring the importance of routine resistance surveillance in dairy farms. Full article

Staphylococcus aureus and Klebsiella pneumoniae are significant and prevalent pathogens associated with bovine mastitis on dairy farms worldwide, resulting in severe infections in both dairy cows and, subsequently, human beings. Fast and dependable pathogen diagnostics are essential to minimize the effects of cow mastitis and human infections. The aim of this research was to develop a duplex recombinase-aided amplification (RAA) combined with the lateral flow dipstick (LFD) method, which was used for rapid, simultaneous detection of S. aureus and K. pneumoniae. The SKII culture medium for S. aureus and K. pneumoniae cocultivation was developed in this study. By optimizing the duplex RAA–LFD reaction conditions in terms of primer concentration, amplification temperature, and reaction time, the duplex RAA–LFD assay could successfully detect S. aureus and K. pneumoniae when the reaction was conducted at 39 °C for 20 min. The duplex RAA–LFD method demonstrated good specificity, exhibiting no cross-reactivity with other pathogens. In addition, the detection limit of the duplex RAA–LFD for S. aureus and K. pneumoniae was 60 fg of genomic DNA and 1.78 × 10³ and 2.46 × 10³ CFU/mL of bacteria in pure culture. Moreover, the duplex RAA–LFD technique is capable of identifying S. aureus and K. pneumoniae in artificially spiked milk samples even at very low initial concentrations of 1.78 × 10¹ and 2.46 × 10⁰ CFU/mL, respectively, after 6 h of enrichment. The result of the actual samples showed that the total concordance rate of the duplex RAA–LFD method with the biochemical identification method and PCR method could reach 92.98~98.25% with high consistency. The results of this study indicated that the duplex RAA–LFD assay, which is a precise, sensitive, and simple field testing technique, can be used to identify S. aureus and K. pneumoniae and is expected to be used for disease diagnosis. Full article

Escherichia coli (E. coli) has the ability to induce clinical and subclinical mastitis in dairy cows, causing a huge loss for the dairy industry. In this study, 51 subclinical mastitis isolates and 36 clinical mastitis isolates from eight provinces of China between 2019 and 2021 were used to investigate the differences in their biological characteristics. The results showed that B1 (52.9%) and A (39.1%) were the predominant phylogroups; R1 (50.6%) was the predominant lipopolysaccharide (LPS) core type; and 44 STs (ST10 and ST58 were the most sequence-prevalent STs) and 2 new STs (ST14828 and ST14829) were identified; however, no significant difference was observed between the clinical and subclinical group strains. To compare the virulence gene differences between the clinical and subclinical mastitis-related isolates, 18 common virulence genes (including afaE, eaeA, papC, saa, sfa, ompA, aer, irp2, iucD, escV, sepD, east1, estB, stx2e, CNF1, cba, hlyA and traT) were determined using the PCR method. The results showed that the detection rates of traT, irp2 and iucD in clinical mastitis isolates were significantly higher than those in subclinical mastitis isolates (p ˂ 0.05). Meanwhile, subclinical-group E. coli had stronger biofilm formation abilities than the clinical group (p < 0.05) in 78 (89.7%) mastitis-related E. coli that could form biofilms. Furthermore, 87 mastitis-related E. coli showed severe resistance against tetracycline (37.9%), ampicillin (36.8%), streptomycin (34.5%) and cotrimoxazole (28.7%); their most prevalent resistance genes were blaCTX-M (33.3%), tetA (27.6%), sul2 (18.4%) and strB (28.7%). It was noteworthy that the clinical-group strains had a higher resistance against ampicillin and possessed higher amounts of the resistance gene blaCTX-M (p < 0.05) compared to the subclinical group. This study aims to provide references for preventing the E. coli isolates from inducing different types of mastitis. Full article