Risk factors associated with the occurrence of multiresistant Staphylococcus spp. isolated from bovine subclinical mastitis in northern Brazil

Staphylococcus bacteria are often associated with subclinical bovine mastitis. This study aimed to identify multiresistant Staphylococcus spp. associated with subclinical mastitis and the associated risk factors. Twenty-three dairy farms with a history of decrease in milk production, located in the lower Acre region, Brazil, were selected. An epidemiological questionnaire was provided in all farms. All animals were examined using the California Mastitis Test (CMT) and their milk samples were collected for bacterial culture. After isolation and identification, the disk diffusion antimicrobial susceptibility test was performed against nine classes of antimicrobials. Of the 339 cows examined using the CMT, 108 had mastitis. A total of 229 milk samples were collected from individual teats. MALDI-TOF MS found isolates belonging to eight species of Staphylococcus, in 101 of these samples. S. chromogenes (58.4%) demonstrated strongest resistance to the nine classes of antimicrobial active principles. Nineteen isolates with multidrug resistance phenotypic profile were identified. This phenotypic expression indicates wide circulation of resistant genes in this species. The presence of multidrug resistance in Staphylococcus spp. in this study was correlated with lack of water for cleaning the corral, which is a preventive factor, minimizing the transmission and persistence of pathogens in the farms.

Propolis in the control of bacterial bovine mastitis: a tool for the production of organic milk

Bovine mastitis is one of the main causes of economic damage in dairy farms. Therefore, the control and prevention of microorganisms involved in this disease, mainly Escherichia coli, Staphylococcus aureus, and Streptococcus agalactiae, are essential. One of the most important steps for the prevention of the disease is the use of antiseptic products before and after the milking process to avoid bacteria from infecting the udder of the animal. Currently, the most used antiseptic product in dairy farms is iodine-based, and organic dairy farms, which follow several strict regulations, including the use of natural products whenever possible, are often forced to adopt non-natural antiseptic products, such as iodine-based ones, because of the lack of natural alternatives. Propolis, a natural substance produced by honeybees, has been extensively studied for its various properties, one of which is antimicrobial activity. Therefore, a new natural antiseptic product containing 1% propolis in 10% hydroalcoholic solution for the pre-dipping, and 10% glycerol solution added with 0.2% citronella oil for the post-dipping was analyzed for its capacity to reduce bacteria in vivo in order to prevent bovine mastitis, allowing its use on organic dairy farms. A total of 128 samples were analyzed in terms of bacterial growth for Enterobacteriaceae and Staphylococcus spp. using the spreadplate technique. The reduction in the bacterial concentration after the application of the products was compared between two antiseptic solutions, an iodine-based solution as the control and a propolis-based one as the natural alternative. The results obtained show a similar efficiency for both products in terms of total bacterial reduction, indicating considerable antimicrobial activity against bacteria most commonly associated with bovine mastitis. Molecular analysis was carried out for the identification of Streptococcus agalactiae; the PCR results were negative for the presence of S. agalactiae in all samples, indicating that the animals most likely did not have any form of the disease. The efficiency of the natural antiseptic was satisfactory, indicating an important find facilitating organic milk production worldwide, showcasing a natural antiseptic solution with efficient antimicrobial activity.

Multi-Omics Integration and Network Analysis Reveal Potential Hub Genes and Genetic Mechanisms Regulating Bovine Mastitis

Mastitis, inflammation of the mammary gland, is the most prevalent disease in dairy cattle that has a potential impact on profitability and animal welfare. Specifically designed multi-omics studies can be used to prioritize candidate genes and identify biomarkers and the molecular mechanisms underlying mastitis in dairy cattle. Hence, the present study aimed to explore the genetic basis of bovine mastitis by integrating microarray and RNA-Seq data containing healthy and mastitic samples in comparative transcriptome analysis with the results of published genome-wide association studies (GWAS) using a literature mining approach. The integration of different information sources resulted in the identification of 33 common and relevant genes associated with bovine mastitis. Among these, seven genes—CXCR1, HCK, IL1RN, MMP9, S100A9, GRO1, and SOCS3—were identified as the hub genes (highly connected genes) for mastitis susceptibility and resistance, and were subjected to protein-protein interaction (PPI) network and gene regulatory network construction. Gene ontology annotation and enrichment analysis revealed 23, 7, and 4 GO terms related to mastitis in the biological process, molecular function, and cellular component categories, respectively. Moreover, the main metabolic-signalling pathways responsible for the regulation of immune or inflammatory responses were significantly enriched in cytokine–cytokine-receptor interaction, the IL-17 signaling pathway, viral protein interaction with cytokines and cytokine receptors, and the chemokine signaling pathway. Consequently, the identification of these genes, pathways, and their respective functions could contribute to a better understanding of the genetics and mechanisms regulating mastitis and can be considered a starting point for future studies on bovine mastitis.

Hyperoside inhibits lipopolysaccharide-induced mastitis in mice by inactivating the NLRP3 inflammasome

IntroductionThe impact of bovine mastitis on animal husbandry is great huge. It is anincurable an incurable disease mainly characterized by milk and pathological changes in milk and the mammary gland, which causescause reduced yield and quality of milk, but. Unfortunately, the use of antibiotics to combat mastitis affects the production of milk, so it is urgent to find additional therapeutic molecules for mastitis treatment.Material and methodsIn this study, we analyzed the protection provided by hyperoside (HYP) in a model of mastitis in vivo and explored its functional mechanism in mouse mammary epithelial cells (mMECs) by overexpression of NOD-, LRR- and pyrin domain-containing 3 (NLRP3).ResultsOur results showed that HYP at 12.5, 25 and 50 mg/kg prevented the inflammatory response induced in lipopolysaccharide (LPS)-stimulated micemouse mammary glands as well as inflammatory cytokine production, including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β and IL-8. The protection provided by HYP was also correlated with the reduction of NLRP3 signaling pathway protein levels in vivo. However, overexpression of NLRP3 reversed the effects of HYP on the NLRP3 inflammasome, cell viability and inflammatory factor levels in LPS-stimulated mMECs.ConclusionsIn summary, this study showed that HYP inhibited LPS-stimulated symptoms of breast inflammation by regulating expression of inflammatory cytokines and inhibiting the NLRP3 signaling pathway.

Etiology of Mastitis and Antimicrobial Resistance in Dairy Cattle Farms in the Western Part of Romania

The present study aimed to determine the bacteria isolated from bovine mastitis and their antimicrobial resistance in the western part of Romania. Clinical mastitis was diagnosed based on local inflammation in the udder, changes in milk, and when present, generalized symptoms. Subclinical mastitis was assessed using a rapid test—the California Mastitis Test. The identification of bacterial strains was performed based on biochemical profiles using API system tests (API 20 E, API Staph, API 20 Strep, API Coryne, API 20 NE (bioMerieux, Marcy l’Etoile, France), and MALDI-TOF mass spectrometry (MS). The prevalent isolated bacteria were Staphylococcus spp. (50/116; 43.19%), followed by Streptococcus spp. (26/116; 22.41%), E. coli (16/116; 13.79%), Corynebacterium spp. (9/116; 7.75%), Enterococcus spp. (10/116; 8.62%), and Enterobacter spp. (5/116; 4.31%). Phenotype antimicrobial resistance profiling was performed used the disc diffusion method. Generally, Gram-positive bacteria showed low susceptibility to most of the antimicrobials tested, except cephalothin. Susceptibilities to penicillins and quinolones were fairly high in Gram-negative bacteria, whereas resistance was observed to macrolides, aminoglycosides, and tetracyclines. The highest number of isolates were multidrug resistant (MDR), the resistance pathotypes identified including the most frequently antimicrobials used in cow mastitis treatment in Romania.

Training, development, and evaluation of on-farm culturing as a technical resource to reduce the use of antimicrobials in dairy herds in the Midwest Region of Santa Catarina State, Brazil

ABSTRACT: On-farm culturing is a technology booming in Brazil. It is based on the microbiological diagnosis of milk samples collected from clinical cases of bovine mastitis, on the farm where the animals are handled, quickly, simply, and at an affordable cost. With this resource, after 24 h of incubation, the isolated microorganisms are classified as gram positive or gram negative, helping to make decisions regarding the therapy of the animals. Considering the relevance of the Midwestern region of Santa Catarina State in the national dairy production scenario, the objectives of the study were: 1) to promote the technical training of the farmers in three dairy farms located in Treze Tílias-SC, 2) to assist in the implementation and evaluation of on-farm culturing as technological resource viewing the reduced use of antimicrobials in herds. In addition to the rapid acceptance by the farmers and their efficient training, with the use of the technology, there was a 45-50% reduction in the use of antimicrobials in dairy herds. This result demonstrated a significant effect on animal health, and determines an important cost reduction for farmers, as presented in detail in this manuscript.

Pathogens isolated from bovine clinical mastitis and their antimicrobial resistance

This study aimed to isolate aerobic and microaerophilic bacteria from mastitis milk samples, as well as to determine their antibiotic resistance. A total of 196 bovine mastitis milk samples were tested by standard bacteriological methods and with API identification test kits. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method. The results revealed that the predominant isolate was S. aureus, with an isolation rate of 28%, followed by Streptococcus spp. (27%) and E. coli (19%). Isolation rates for Corynebacterium spp., Mycoplasma spp., and Pseudomonas aeruginosa were 11%, 6%, and 4%, respectively. Compared to the bacteria mentioned above, lower percentages were observed for Trueperella pyogenes (2%), Pasteurella multocida (2%), and Klebsiella pneumoniae (1%). A broad evaluation of antimicrobial resistance showed that the pathogens were resistant to tetracycline (68.63%), oxytetracycline (41.57%), ampicillin (39.08%), ceftiofur (38.1%), cephalexin (32.26%), penicillin (31.25%), amoxicillin/clavulanic acid (24.53%), enrofloxacin (24.44%), gentamycin (23.68%), and trimethoprim/sulfamethoxazole (22.09%). This study demonstrated that the sources of bacteria isolated from mastitis bovine milk samples were both contagious and environmental. More importantly, the present results demonstrate a critically high antimicrobial resistance in dairy cattle. For instance, E. coli isolates showed a crucial resistance to commonly used and recommended antimicrobials, including ceftiofur (100%), cephalexin (83.33%), and tetracycline (94.44%). The results of this study may provide valuable information about clinical aspects of bovine mastitis infections and current antimicrobial resistance levels in dairy cattle.

mecA positive Staphylococcus spp. in bovine mastitis, milkers, milking environment, and the circulation of different MRSA clones at dairy cows farms in the Northeast region of Brazil

ABSTRACT: This study detected the presence and distribution of mecA in Staphylococcus spp. in the dairy production environment at farm level in Brazil. We analyzed 335 samples of mastitis cow milk, 15 samples of nostrils and hand swabs from milkers, 14 teat cup swabs, and 9 milking buckets swabs. Initially, the samples were subjected to microbiological analysis to detect Staphylococcus spp. and then S. aureus and mecA positive isolates were identified by PCR. All S. aureus isolates carrying the mecA genes were subjected to DNA macro-restriction analysis by Pulsed-Field Gel Electrophoresis (PFGE). The mecA gene was detected in 6/335 (1.78%) of mastitis cow milk, 5/15 (33.3%), and 5/15 (33.3%) of nostrils and hand swab, and 4/14 (28.5%) of the teat cup isolates. MRSA genotyping was performed by PFGE, a total of seven pulsotypes were grouped in two clusters. This study identified the occurrence and spread of MRSA at dairy environment of farms, and also the existence of distinct genetic profiles between isolates.