Search Results (45)

The Atacama Desert, an unexplored habitat, offers intriguing potential for natural product chemistry due to the unique adaptations of microorganisms to aridity, extreme salinity, and high UV radiation. Over several years, soil samples were collected from various locations across the desert, leading to the isolation of diverse microorganisms. This paper presents the isolation and structural characterisation of two new 10-membered lactones, curvulalide B and C (3 and 4). These compounds are epimers of each other and are produced by one of the fungi isolated from the samples collected, using LC–MS and 1D and 2D NMR techniques. The compounds were tested against the ESKAPE pathogens, bovine mastitis pathogens, and Cryptococcus neoformans but were inactive against them. Full article

Subclinical mastitis is a critical disease affecting camel health and milk quality. However, research on shifts in milk bacterial communities following subclinical mastitis in camels is limited. We evaluated changes in bacterial communities following subclinical mastitis in Bactrian camels. Three portions of California Mastitis Test (CMT)-negative milk and five portions of CMT-positive milk were collected from each Jimunai County and Keping County using the CMT, and the bacterial community composition of the camel milk was analyzed using amplicon sequencing of the v34 region of the 16S rRNA gene. Subclinical mastitis induced genus-level differences in the core bacterial microbiota of Bactrian camel milk. To our knowledge, Delftia was identified in camel milk for the first time, predominantly in Jimunai County. Bacterial abundance in camel milk from Keping County was increased and altered. Alpha diversity analysis revealed that subclinical mastitis induced lower and higher bacterial abundance in milk from Jimunai County and Keping County, respectively, compared to that of healthy camels. Therefore, these findings provide direction for future research on pathogenic microorganisms for the prevention and control of subclinical mastitis in Bactrian camels. Full article

Mastitis is defined as mammary gland inflammation and is one of the most common and economically significant diseases affecting dairy cows. Bacteria are the most frequently reported agents responsible for mastitis, while other pathogens are often overlooked due to insufficient routine investigation. Incomplete diagnoses can result in inappropriate antimicrobial treatments, treatment failures, antimicrobial resistance, the spread of pathogens, and the recurrence of mastitis. Background/Objectives: This study aimed to investigate the presence of Staphylococcus spp. associated with Romanian buffalo mastitis on dairy farms in Western Romania via a bacteriological analysis of mastitis milk and determine antimicrobial susceptibility profiles. Methods: Bacterial culture was performed according to the guidelines described by the National Mastitis Council. Vitek 2 Compact systems (Bio Mérieux, France), with the GP ID cards, were used to confirm the species of the isolates. Antibiotic susceptibility testing was conducted by utilizing Vitek^® 2 preset antimicrobial card AST-GP79 Gram-positive Livestock WW. Results: Of all the milk samples (n = 115) analyzed, 83 were positive for Staphylococcus spp. (72.17%) and were evaluated for their antimicrobial susceptibility profiles. The most common microorganism found was S. aureus (n = 46; 55.42%), followed by S. hyicus (n = 28; 33.73%) and S. schleiferi (n = 9; 10.84%). These pathogens demonstrated significant resistance to the tetracycline, neomycin, benzylpenicillin, and erythromycin. Conclusions: Current control measures for mastitis caused by S. aureus are ineffective. A better understanding of the virulence factors in Romanian buffalo-adapted strains of S. aureus, their pathogenesis, and host immunological responses is essential for developing effective and sustainable non-antibiotic control tools such as vaccines, prophylactic therapies, and other innovative approaches. 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

Pre- and post-milking teat antisepsis is one of the most effective methods for reducing the incidence of mastitis. Plant extracts have proven effective in reducing microorganisms, providing a natural alternative for antisepsis, along with additional benefits for teat health. This study aimed to evaluate the antimicrobial and antiseptic effects of two newly formulated products, used as pre-dipping and post-dipping agents, respectively, based on plant extracts from papain (Carica papaya), aloe vera (Aloe barbadensis), andiroba (Carapa guianensis), copaiba (Copaifera officinalis), tea tree (Melaleuca alternifolia), and barbatimão (Stryphnodendron barbatiman). Minimum inhibitory concentration tests were performed in vitro, along with microbiological analyses of different bacterial groups and in vivo compliance assessments to evaluate the antimicrobial activity of the formulations, as well as the molecular identification of Staphylococcus aureus. The results demonstrated that the products were effective in vitro against the main pathogens that cause mastitis, including Staphylococcus aureus, Streptococcus agalactiae, and Escherichia coli. In the in vivo assays, similar performance was observed between the tested products and the control products, indicating that the plant-extract-based formulations, applied as pre-dipping and post-dipping agents, effectively reduced the microbial load on the teats. The effects were equivalent to those of hydrogen-peroxide- and iodine-based products, being able to reduce the total microbial load by more than 80%. Full article

This study explores the potential of silver nanoparticles (AgNPs) synthesized through an eco-friendly method using coffee extract to combat non-bacterial mastitis in dairy cattle. Mastitis, often caused by pathogens such as yeasts and algae like Prototheca spp., poses a challenge due to the limited efficacy of traditional antibiotics. This research utilized strains isolated from mastitis milk and assessed the nanoparticles’ physicochemical properties, antimicrobial efficacy, and impact on biofilm formation and microorganism invasion. AgNPs demonstrated a spherical shape with a mean hydrodynamic diameter of ~87 nm and moderate colloidal stability. Antimicrobial tests revealed significant growth inhibition of yeast and Prototheca spp., with minimal inhibitory concentrations (MICs) as low as 10 mg/L for certain strains. Biofilm formation was notably disrupted, and microorganism invasion in bioprinted gels was significantly reduced, indicating the broad-spectrum potential of AgNPs. The study highlights the nanoparticles’ ability to damage cell membranes and inhibit metabolic activities, presenting a promising alternative for managing infections resistant to conventional treatments. These findings suggest that green-synthesized AgNPs could play a pivotal role in developing sustainable solutions for mastitis treatment, particularly for pathogens with limited treatment options. 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: Despite penicillin having a longstanding reputation as being scientifically approved for the treatment of bovine mastitis, its market share and practical application rate seem rather low. While in some countries, cases of mild and moderate mastitis are treated almost completely with simple penicillin, in other countries, penicillin is rarely used as a mono-substance in udder tubes. Methods: Based on minimal inhibitory concentration (MIC) studies of 1489 isolates of Gram-positive microorganisms isolated from bovine mastitis cases, the extent to which penicillin preparations can fulfil their role as first-line treatment and in how many cases insufficient efficacy must be assumed was assessed in comparison with more recent studies on the achievable levels of active substances in milk. Results: Of the isolates, 76% had an MIC of ≤0.125 µg/mL and 95% of the isolates had an MIC of ≤1 µg/mL. Conclusions: The data show that in Northern Germany, it can be assumed that penicillin is a good choice in most cases of mastitis caused by Gram-positive mastitis pathogens, at least from the perspective of antibiotic resistance. Full article

Clostridioides difficile currently constitutes a major pathogen of the gastrointestinal tract, which poses a significant growing burden on medicine and veterinary medicine in many regions. A farm was assessed (feed table, silage pit, and feces (healthy animals, emaciated animals, and animals with mastitis)) for the presence of C. difficile toxins using the PCR method and for the microbiome in cow feed and feces using NGS technology, one month apart. C. difficile toxin A and binary toxin were detected in feed samples. C. difficile toxin genes were found in the feces of sick animals two to three times more often than in healthy animals. Analysis of the microbial community of cow feces revealed that, during the month, the animals experienced major changes in the community structure associated with the accumulation of pathogenic bacteria, in particular Paeniclostridium sp., as well as with the development of methanogenic archaea of the Methanobacteriaceae and associated microorganisms (Lachnospiraceae and Anaerovoracaceae), which may speak of a decrease in feed efficiency and, subsequently, animal productivity. Thus, it seems likely that C. difficile enters the gastrointestinal tract of animals through feed, while animals weakened by diseases are more sensitive to the reproduction of pathogens in the GIT due to a weakened organism. Full article

Milking methods have significant impacts on the microbiological composition, which could affect the quality of raw buffalo milk. Hence, the current study was conducted on the impact of milking methods on microorganisms in buffalo tank raw milk from 15 farms in Guangxi, China. The farms were divided into two groups based on the milking method: mechanical milking (MM, n = 6) and hand milking (HM, n = 9). Somatic cell counts, bacterial cell counts and nutrients of the raw buffalo milk samples were analyzed. The comparison of raw buffalo milk samples was analyzed using metagenomic sequencing to detect any differences between the two groups. There was no significant difference in the basic nutritional compositions and somatic cell count of raw buffalo milk between the two milking methods. However, the HM samples had significantly higher bacterial counts and diversity compared to the MM samples. The results showed that Staphylococcus spp., Klebsiella spp., Streptococcus spp., and Pseudomonas spp. were the major microbes present in canned raw buffalo milk. However, the differences between the two milking methods were the relative abundance of core microorganisms and their potential mastitis-causing genera, including the content of antibiotic-resistance genes and virulence genes. Our study revealed that Staphylococcus spp. and Streptococcus spp. were significantly more abundant in the MM group, while Klebsiella spp. was more abundant in the HM group. Regardless of the milking method used, Pseudomonas spp. was identified as the primary genus contributing to antibiotic resistance and virulence genes in canned raw buffalo milk. These findings affirm that there are differences in the microbial and genomic levels in canned raw milk. To prove the functional roles of the discovered genes and how these genes affect milk quality, further research and experimental validation are necessary. Full article

Mastitis is an inflammation of the mammary gland that can be caused by various factors, including biological, chemical, mechanical, or physical. Microbiological culture, DNA techniques, and high-throughput next-generation sequencing have been used to identify mastitis-causing pathogens in various animal species. However, little is known about microbiota and microbiome changes linked to yak milk mastitis. This study aimed to characterize the milk microbiota of healthy and mastitis-infected yaks using full-length 16S rRNA sequencing. The results showed that the bacterial microbiota comprises 7 phyla, 9 classes, 20 orders, 39 families, 59 genera, and 72 species. Proteobacteria and Firmicutes were the predominant microbial communities, with lower abundances of Bacteroidota, Actinobacteriota, Acidobacteriota, and other minor groupings also observed. Proteobacteria dominated the clinical and subclinical mastitis groups (95.36% and 89.32%, respectively), in contrast to the healthy group (60.17%). Conversely, Firmicutes were more common in the healthy group (39.7%) than in the subclinical and clinical mastitis groups (10.49% and 2.92%, respectively). The predominant organisms found in the healthy group were Leuconostoc mesenteroides, Lactococcus piscium, Carnobacterium maltaromaticum, and Lactococcus raffinolactis. Low abundances of Staphylococcus aureus species were found in both subclinical and clinical mastitis groups, with Moraxella osloensis and Psychrobacter cibarius dominating the subclinical mastitis group and Pseudomonas fluorescens dominating the clinical mastitis group. An alpha diversity study revealed that the healthy group had a higher microbial diversity than the clinical and subclinical mastitis groups. According to beta-diversity analysis, the principal coordinate analysis identified that mastitis-infected samples significantly differed from healthy ones. The milk microbiota of healthy yaks is more varied, and specific prominent taxa within various groups can act as marker microorganisms for mastitis risk. The genera Leuconostoc and Lactococcus are promising candidates for creating probiotics. Full article

Mastitis is a common mammary gland disease of dairy cattle caused by a wide range of organisms including bacteria, fungi and algae. Mastitis contributes to economic losses of dairy farms due to reduced yield and poor quality of milk. Since the correct identification of pathogens responsible for the development of mastitis is crucial to the success of treatment, it is necessary to develop a quick and accurate test to distinguish the main pathogens causing this disease. In this paper, we describe the development of a test based on the multiplex polymerase chain reaction (PCR) method allowing for the identification of Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis and Staphylococcus aureus. When creating our test, we relied on the results from new generation sequencing (NGS) for accurate determination of species affiliation. The multiplex PCR test was verified on 100 strains including veterinary samples, ATCC and Polish Collection of Microorganisms (PCM) reference strains. The obtained results indicate that this test is accurate and displays high specificity. It may serve as a valuable molecular tool for the detection of major mastitis pathogens. Full article

Microorganisms are a valuable source of pharmaceutically active chemicals, serving as scaffolds for synthesis as well as lead structures. Investigating novel biomes frequently yields intriguing chemistry; the Atacama Desert in Chile is one such example. This study reports the isolation of a new reduced anthracycline-related compound from the Atacama Desert-derived bacterium Saccharothrix S26. Structural characterisation was achieved by one-dimensional and two-dimensional NMR, HR-LCMS, and X-ray crystallography. The compound was tested against the ESKAPE pathogens, bovine mastitis-related pathogens, and the fungal strain Cryptococcus neoformans, but no antimicrobial activity was observed. Full article

Prototheca bovis (P. bovis), an alga that has attracted considerable attention over the years as a causative microorganism of mastitis in dairy cows, exhibits limited susceptibility to specific aminoglycosides and antifungal agents, and no effective clinical treatment is currently available, thereby posing challenges for both prevention and treatment. To investigate the infection of P. bovis mastitis and its impact on raw milk production, a total of 348 raw milk samples were collected from August to December 2022 from a dairy farm in central China. P. bovis and other bacteria were detected, and the average infection rate of P. bovis in raw milk was 60.34% (210/348). The total number of colonies and the somatic cell count (SCC) of P. bovis positive samples were significantly higher than those of P. bovis negative samples (p < 0.01). The daily milk yield, 305-day milk yield, peak milk yield, and days to peak milk yield of the P. bovis positive samples were significantly lower than those of P. bovis negative samples (p < 0.01). A correlation analysis showed that P. bovis infection was negatively correlated with daily milk yield, 305-day milk yield, peak milk yield, and days to peak milk yield (p < 0.0001), while being positively correlated with the total number of colonies, SCC, milk loss, and protein percentage (p < 0.0001). These findings may help practitioners in comprehending the occurrence of Prototheca mastitis and developing more effective strategies for the prevention of P. bovis infections. Full article

Milk is an excellent medium for the growth of several bacteria and other microorganisms and thus, it has been extensively studied. An always current issue in the dairy industry is mastitis, which causes losses in milk volume and profits. In many cases, milk is used raw or treated at low temperatures for further dairy processes while there are quite a few cases in which foodborne-related outbreaks have occurred. Both culture-based methods and PCR were used to assess the presence of certain pathogens related to both contagious and environmental pathogens, especially the emerging pathogenic bacterium Klebsiella pneumoniae, as well as Staphyloccocus aureus and Enterobacter spp., which are associated with mastitis in milk samples from different lactating ruminant species (cows, goats, and sheep) and to further evaluate the significance of the isolated pathogens to public health. Even though significant mastitis contagious pathogens such as Staphylococcus aureus and Staphylococcus epidermidis were not detected, environmental pathogens related to poor hygiene conditions at the farm level (K. pneumoniae, Staphylococcus saprophyticus, and Enterococcus spp.) were detected. In particular, K. pneumoniae and Staphylococcus saprophyticus were present in ovine milk samples while bovine and caprine milk samples were contaminated with Enterococcus spp. The presence of these bacteria underlines the significant role of environmental hygiene especially since Staphylococcus saprophyticus and Enterococcus spp. are related to urinary tract infections and all of the tested pathogens may carry antibiotic resistance genes. More specifically, 20% of the isolated Klebsiella pneumoniae strains were found resistant to carbapenem antibiotics. The presence of emerging K. pneumoniae in ovine milk samples also indicates the need for new policies in terms of safety testing. Suggestions of monitoring processes carried out by the relevant authorities are discussed. Full article