Subclinical Mastitis Cases Research Articles

Identification of Inflammatory and Regulatory Cytokines IL-1α-, IL-4-, IL-6-, IL-12-, IL-13-, IL-17A-, TNF-α-, and IFN-γ-Producing Cells in the Milk of Dairy Cows with Subclinical and Clinical Mastitis.

In naturally occurring bovine mastitis, effects of infection depend on the host inflammatory response, including the effects of secreted cytokines. Knowledge about the inflammatory and regulatory cytokines in milk cells of free-stall barn dairy cows and in naturally occurring mastitis is lacking as most studies focus on induced mastitis. Hereby, the aim of the study was to determine inflammatory and regulatory cytokines in the milk of dairy cows with subclinical and clinical mastitis. The following examinations of milk samples were performed: differential counting of somatic cells (SCC), bacteriological examination, and immunocytochemical analysis. Mean SCC increased in subclinical and clinical mastitis cases. The number of pathogenic mastitis-causing bacteria on plates increased in subclinical mastitis cases but decreased in clinical mastitis. The inflammatory and regulatory markers in the milk cells of healthy cows showed the highest mean cell numbers (%). In mastitis cases, immunoreactivity was more pronounced for IL-4, IL-6, IL-12, IL-13, IL-17A, TNF-α, and IFN-γ. Data about subclinical and clinical mastitis demonstrate inflammatory responses to intramammary infection driven by IL-1α, IL-4, and IL-17A. Moreover, the host defense response in mastitis is characterized by continuation or resolution of initial inflammation. IL-12 and INF-γ immunoreactivity was recognized to differ mastitis cases from the relative health status.

Genome-Wide DNA Methylation and Its Effect on Gene Expression During Subclinical Mastitis in Water Buffalo.

Subclinical mastitis (SCM) in buffalo is one of the most challenging paradoxes for the dairy sector with very significant milk production losses and poses an imminent danger to milch animal’s milk-producing ability. We present here the genome-wide methylation specific to SCM in water buffalo and its consequential effect on the gene expression landscape for the first time. Whole-genome DNA methylation profiles from peripheral blood lymphocytes and gene expression profiles from milk somatic cells of healthy and SCM cases were catalogued from the MeDIP-Seq and RNA-Seq data. The average methylation in healthy buffaloes was found to be higher than that in the SCM-infected buffaloes. DNA methylation was abundant in the intergenic region followed by the intronic region in both healthy control and SCM groups. A total of 3,950 differentially methylated regions (DMRs) were identified and annotated to 370 differentially methylated genes (DMGs), most of which were enriched in the promoter region. Several important pathways were activated due to hypomethylation and belonged to the Staphylococcus aureus infection, Th17 cell differentiation, and antigen processing and presentation pathways along with others of defense responses. DNA methylome was compared with transcriptome to understand the regulatory role of DNA methylation on gene expression specific to SCM in buffaloes. A total of 4,778 significant differentially expressed genes (DEGs) were extracted in response to SCM, out of which 67 DMGs were also found to be differentially expressed, suggesting that during SCM, DNA methylation could be one of the epigenetic regulatory mechanisms of gene expression. Genes like CSF2RB, LOC102408349, C3 and PZP like, and CPAMD8 were found to be downregulated in our study, which are known to be involved in the immune response to SCM. Association of DNA methylation with transposable elements, miRNAs, and lncRNAs was also studied. The present study reports a buffalo SCM web resource (BSCM2TDb) available at http://webtom.cabgrid.res.in/BSCM2TDb that catalogues all the mastitis-related information of the analyses results of this study in a single place. This will be of immense use to buffalo researchers to understand the host–pathogen interaction involving SCM, which is required in endeavors of mastitis control and management.

Use of photodynamic therapy and photobiomodulation as alternatives for microbial control on clinical and subclinical mastitis in sheep.

Evaluate the effects of antimicrobial photodynamic therapy (aPDT) and photobiomodulation (PBM) as alternatives in the treatment of mastitis in sheep. A total of 100 sheep were evaluated, and four teats with clinical mastitis and 16 teats with subclinical mastitis were selected. Milk was collected for isolation and identification of microorganisms. They were grown on TSA, EMB, and MacConkey agar for 24h, and the microorganisms were identified by Gram stain and biochemical tests. The ceilings were subdivided into four groups: G1, treatment with photosensitizer; G2, treatment with PBM (diode laser λ = 660nm); G3, aPDT with methylene blue, and G4, control group. Milk samples were collected before, 24 and 48h after treatments. Cases of subclinical mastitis presented coagulase-negative Staphylococcus and Streptococcus spp, and clinical mastitis had Escherichia coli grow from the samples. The treatments decrease the total bacterial count of negative coagulase Staphylococcus, Streptococcus spp, and Escherichia coli. Comparing the treatments, aPDT stood out, as it was able to photoinactivate all bacteria. Treatment with methylene blue photosensitizer, PBM, and aPDT induced the initial microbial reduction, but aPDT was more effective 48h after treatment.

Molecular detection of quaternary ammonium compound resistance genes of Staphylococcus aureus from udder surface and mastitis milk of bovines

Quaternary ammonium compounds (QAC) are widely used biocides in the field of medical and veterinary practice. Resistance to QACs is an emerging problem due to this widespread use. The present study was undertaken to detect the presence of genes that contribute to resistance to QACs in Staphylococcus aureus isolates obtained from udder surface and mastitis milk. A total 22 isolates of S. aureus were obtained from udder washings and milk of bovine mastitis cases. Among these, seventeen isolates were from udder wash samples and five isolates from clinical and subclinical cases of mastitis. Broth microdilution assay was performed to assess the minimum inhibitory concentration (MIC) of the isolates against Cetyltrimethylammonium bromide (CTAB), a QAC. Polymerase chain reaction (PCR) was done targeting qac A/B gene which codes for efflux pump which targets QACs. In the present study qac A/B gene was detected in seven out of 22 isolates of S. aureus. Three of these isolates were obtained from udder washings before milking and four, after milking. None of the S. aureus isolates from mastitis milk possessed the gene. The average minimum inhibitory concentration of qac A/B positive isolates against CTAB was 0.63 ± 0.55 μg/ml. The average MIC between qac A/B positive and negative isolates were statistically insignificant. The study points to the fact that multiple factors could be contributing to biocide resistance in S. aureus.

Clinical and subclinical mastitis in buffalue in Mosul area, Iraq

This paper aims to investigate the occurrence of clinical and sub-clinical cases of mastitis in buffaloes, and to identify the differences in the components of the mastitis milk, to facilitate the investigation of a number of epidemiological risk aspects in relation to the occurrence of mastitis and to detect the different bacterial species associated with the disease. Eight hundred buffalo milk samples were randomly extracted from the animals of different ages in Mosul city, Iraq and examined by California mastitis test (CMT) and Ultrasonic milk analyzer. According to the clinical signs and CMT, the results indicated the prevalence of the clinical and subclinical cases of the disease in buffaloes to be 10.62% and 27.37% respectively. There was a substantial rise in the population of somatic cells /ml in both clinical and subclinical cases of mastitis. The risk factors included third trimester of lactation period, old ages 10-11 years, outdoor feeding animals, > 30 buffaloes/herd, northern and southern parts of the city, Spring and Winter seasons. In clinical instances of mastitis, the occurrence of Staphylococcus aureus was 25.88%, Streptococcus agalactiae 18.82%, Streptococcus pyogenes 16.47%, Corynebacterium bovis 14.11%, Escherichia coli 10.58%, Pseudomonus aeruginosa 7.05%, and Pasteurella multocida 7.05%. In the subclinical cases of mastitis, the prevalence of Staphylococcus chromogens was 14.61%, Staphylococcus xylosus 12.78%, Streptococcus agalactiae 11.87%, Streptococcus dysagalactiae 11.41%, Streptococcus uberis 10.04%, Proteus vulgaris 10.04%, Klebsiella pneumonae 9.58%, Escherichia coli 8.21%, Corynebacterium bovis 7.30%, and Pasteurella multocida 4.10%. It is concluded that mastitis leads to a significant reduction in the levels of total solids, lactose, protein, fat, density, and a significant rise in the levels of pH values and electrical conductivity of the milk samples of clinical and subclinical cases of mastitis.

Risk factors for intramammary infection in meat- and pelt producing ewes with clinically healthy udders

Mastitis is prevalent both in milk- and meat- and pelt producing sheep flocks and is an important disease with substantial effects on economy, animal welfare and antibiotic use, and in dairy flocks also on milk quality and safety. In meat- and pelt producing flocks, the farmers are mainly concerned by clinical mastitis (CM), and most cases of subclinical mastitis (SCM) are not detected and not dealt with, posing a risk for poor udder health in the flock. Studies on risk factors for SCM and/or intramammary infections (IMI) in meat producing flocks are scarce and specific risk factors for weaning and lambing are absent. The aim of this study was therefore to investigate associations between risk factors, at ewe and flock level, for IMI after lambing and at weaning in Swedish meat- and pelt producing ewes with clinically healthy udders. Twenty-two meat- and pelt producing flocks from different parts of Sweden were enrolled in this cross-sectional study. Udder half milk samples were collected at weaning and after lambing from ewes with clinically healthy udders, for bacteriological investigations. Data on ewe and flock level risk factors were recorded. In total, 753 ewes were sampled at least once, and the overall IMI prevalence was 22.5 %. Older ewes, ewes with three or more lambs, ewes that were hard to milk when collecting a milk sample, ewes in moderate size flocks, in flocks with hay as a bedding material and in flocks with less cases of CM had higher risk of IMI. Most of the risk factors associated with IMI in this study differed between weaning and lambing. This study has provided us with novel knowledge on how different factors influence udder health of meat- and pelt producing ewes.

Interrelationship of milk acute-phase proteins and casein percentage in cows and buffaloes subclinical mastitis.

A total number of 62 clinically healthy dairy animals of three farms located in Kafr El Sheikh governorate, Egypt, were subjected to field screening surveys of subclinical mastitis (SCM) using California mastitis test (CMT). The obtained results revealed that 38.80% of quarter milk samples were positive to CMT. The most frequently major causative agents isolated from the positive CMT samples were Escherichia coli, Staphylococcus aureus, and environmental streptococcus spp. Acute-phase proteins (APPs), as immunological biomarkers for SCM, including milk serum amyloid A (mSAA) and haptoglobin (Hp) were measured using ELISA. A significant positive correlation was found between the severity of the mammary infection of cow's quarter milk samples represented in somatic cell count (SCC) and each of APPs and pH values. The correlation coefficient (R) between SCC and mSAA, Hp and pH were 0.54, 0.38 and 0.73, respectively. On the other hand, there was a significant negative correlation between casein percentage in milk of SCM cases, and each of APPs, pH and the presence of bacterial pathogens in the milk samples. The obtained results threw light on the inter-relationship between SCC, mSAA, pH value and casein percentage in milk of cows and buffalo suffered from SCM. The percentage of casein in milk is considered a significant accurate tool for diagnosis of SCM and this finding offers the farmers a cheap and fast selection for diagnosis of such disease. These results presented a specific structured view on the efficacy of different diagnostic tools of SCM in dairy herds.

Genetic Characterization of Staphylococcus aureus From Subclinical Mastitis Cases in Dairy Cows in Rwanda.

Whole-genome sequencing was carried out on 30 Staphylococcus (S.) aureus isolates from dairy cows with subclinical mastitis from all five provinces of Rwanda. Twenty-five of the isolates produced enough sequence to be analyzed using core genome multilocus sequence typing (cg-MLST). The isolates group into three main clusters. The largest cluster contain isolates of sequence type (ST) 152 (n = 6) and the closely related ST1633 (n = 2). These sequence types have previously mainly been encountered in humans. The isolates of the second-largest cluster belong to ST5477 (n = 5),so far exclusively isolated from cows in Rwanda. The third cluster consists of isolates of ST97 (n = 4), which is a well-known bovine-adapted sequence type. These three clusters were all widespread over the country. Isolates of the usually human-adapted sequence types 1 (n = 2) and 5 (n= 1) were found and a single isolate of ST2430, previously found among humans in Africa. Finally, four isolates of novel sequence types were found: ST7108 (n = 2), ST7109 (n = 1), and ST7110 (n = 1). The blaZ penicillin resistance gene was found in 84% of the isolates and was in all cases corroborated by phenotypic resistance determination. Five (20%) of the isolates carried a tetracycline resistance gene, tet(K) or tetM, and three of these five also displayed phenotypic resistance while two isolates carried a tetM-gene but were yet tetracycline susceptible. Seven (28%) isolates carried the dfrG gene conferring resistance to trimethoprim. Four of these isolates indeed were resistant to trimethoprim while three isolates were sensitive. The str gene conferring resistance to aminoglycosides was found in three isolates; however, none of these displayed resistance to gentamycin. Our data revealed a high diversity of the sequence types of S. aureus isolates from cows with subclinical mastitis in Rwanda. Two major clusters of ST97 and ST5477 are likely to be bovine adapted and cause mastitis while the third cluster of ST152 usually have been found in humans and may signify a recent transmission of these types from human to cows, for example from hand milking. The high prevalence of this sequence type among dairy cows may pose zoonotic threat. The sequence types were widely distributed without any geographic correlation. Penicillin resistance, the most common type of resistance with a prevalence over 80%, but also tetracycline and trimethoprim resistance were displayed by several isolates.

The relationship between subclinical mastitis and reproductive performance of etawa crossbreed (PE) goat in Kokap, Kulonprogo, Yogyakarta

Etawa crossbreed (PE) goat farm has been well developed in Kokap, Kulonprogo, and Yogyakarta. The important aspects that support it are doe’s health and reproductive performance. This study aimed to determine the relationship between subclinical mastitis incidence and reproductive performance of the does. This study used 84 does from four different farms, which tested using California Mastitis Test (CMT) to determine the mastitis status. The reproductive performance data gained through a questionnaire and the relation to the mastitis status was analyzed using Chi-square. The result showed that the prevalence of subclinical mastitis was 16.67 % (14 does). In the non-mastitis does, 75.71% had long calving interval (CI), 88.57% had long days open (DO), 44.29% had Litter size (LS) 1, and 12.86% had service per conception (S/C) more than 2. Meanwhile, in the mastitis group, the does with long CI was 71.43%, long DO was 85.71%, LS 1 was 28.57%, and S/C > 2 was 14.29%. The chi-square analyses showed no relationship between subclinical mastitis cases with long CI (X2=0.22), long DO (X2=0.09), LS 1 (X2=1.19), and high S/C (X2=0.02). It can be concluded that there was no relation of mastitis cases to reproductive performance of PE does in Kokap, Kuloprogo, and Yogyakarta.

Comparative Genomic Analysis of Streptococcus dysgalactiae subspecies dysgalactiae Isolated From Bovine Mastitis in China.

Streptococcus dysgalactiae subsp. dysgalactiae (SDSD) is one of the most prevalent pathogens causing bovine mastitis worldwide. However, there is a lack of comprehensive information regarding genetic diversity, complete profiles of virulence factors (VFs), and antimicrobial resistance (AMR) genes for SDSD associated with bovine mastitis in China. In this study, a total of 674 milk samples, including samples from 509 clinical and 165 subclinical mastitis cases, were collected from 17 herds in 7 provinces in China from November 2016 to June 2019. All SDSD isolates were included in phylogenetic analysis based on 16S rRNA and multi-locus sequence typing (MLST). In addition, whole genome sequencing was performed on 12 representative SDSD isolates to screen for VFs and AMR genes and to define pan-, core and accessory genomes. The prevalence of SDSD from mastitis milk samples was 7.57% (51/674). According to phylogenetic analysis based on 16S rRNA, 51 SDSD isolates were divided into 4 clusters, whereas based on MLST, 51 SDSD isolates were identified as 11 sequence types, including 6 registered STs and 5 novel STs (ST521, ST523, ST526, ST527, ST529) that belonged to 2 distinct clonal complexes (CCs) and 4 singletons. Based on WGS information, 108 VFs genes in 12 isolates were determined in 11 categories. In addition, 23 AMR genes were identified in 11 categories. Pan-, core and accessory genomes were composed of 2,663, 1,633 and 699 genes, respectively. These results provided a comprehensive profiles of SDSD virulence and resistance genes as well as phylogenetic relationships among mastitis associated SDSD in North China.

Bacterial pathogens associated with clinical and subclinical mastitis in a Mediterranean pasture-based dairy production system of Australia

Mastitis is an economically important production disease in the dairy industry worldwide. There is limited information on the aetiology of clinical mastitis (CM) and subclinical mastitis (SCM) in Australia's Mediterranean pasture-based production system. A prospective study was conducted in the south-west region of Western Australia to characterise the bacterial pathogens associated with CM and SCM cases and their associated antimicrobial susceptibility profiles. A total of 102 CM and 132 SCM milk samples were collected in twelve dairy farms between April 2020 and September 2020 recovering a total of 310 bacterial isolates. The isolates were evaluated for their antimicrobial susceptibility to twelve antibiotics using the agar disk diffusion (ADD) method. The most common pathogens associated with CM was Bacillus spp. (35.29%), followed by coagulase-negative staphylococci (CNS) (22.55%), Pseudomonas spp. (19.61%), Staphylococcus aureus (10.78%), Escherichia coli (5.88%) and Streptococcus uberis (2.94%). The most common pathogens associated with SCM was CNS (44.70%), followed by Bacillus spp. (30.30%), S. aureus (20.45%), Strep. uberis (15.91%), coliforms (Citrobacter spp., Cronobacter spp., Enterobacter spp., Klebsiella spp., Kosakonia spp., Morganella spp., Serratia spp.) (9.86%), environmental Streptococci (6.06%) and E. coli (6.06%). Beta-lactams resistance was the most common resistance observed in the Staphylococcal isolates and a high proportion of Streptococcal isolates exhibited resistance to enrofloxacin. Overall, the proportion of bacterial pathogens isolated in this study was comparable to the figures reported in other studies in Australia. Future research should focus on risk factors and the determination of resistant genetic components among the common isolates.

Mastitisli Sığırlardan İzole Edilen Stafilokoklarda Antibiyotik Direnci ve Virülens Gen Profilleri

Staphylococcus spp. are the important bacterial agents of subclinical and clinical mastitis cases. This study was aimed to determine the vancomycin resistances, antibacterial resistance profiles, some virulence genes, and pheno- and genotyping of staphylococci from mastitis. For this aim, 121 staphylococcal isolates were analyzed. The identifications of isolates were confirmed with PCR for being Staphylococcus spp. and Staphylococcus aureus. The antibiotic resistance patterns were determined by Kirby bauer Disc Diffusion Tests and according to the resistance profiles, the isolates were antibiotyped. The vancomycin resistance genes were determined by PCR for investigating the vanA, vanH, vanR, vanS, vanZ, vanY and vanX genes. The vancomycin resistant isolates were genotyped with RAPD-PCR. The nuc gene was detected in 86 of 121 staphylococcal isolates examined and named as Staphylococcus aureus. The remaining 35 isolates were defined as Staphylococcus spp. S. aureus isolates were found to be resistant to penicillin G, amoxicillin/clavulanic acid, oxacillin, tetracycline, cefaperazone, teicoplanin, vancomycin and trimethoprim-sulfomethaxazole at 50% (43/86), 40.7% (35/86), 34.9% (30/86), 23.3% (20/86), 22.1% (19/86), 18.6% (16/86) 10.5% (9/86) and 8.1% (7/86) respectively. On the other hand, 4 (11.4%) of 35 Staphylococcus spp. isolates were resistant to penicillin G, 3 (8.6%) to amoxicillin/clavulanic acid, 2 (5.7%) to trimethoprim-sulfometaxazole, 1 (2.9%) to oxacillin, cefaperazone, teicoplanin, while all isolates were sensitive to vancomycin and tetracycline. Of the 9 S. aureus isolates that were phenotypically resistant to vancomycin, vanA gene was detected in 2 and vanR gene in 3 isolates. Multiple resistances to three or more antibiotics were determined in 42 of 86 S. aureus isolates. In addition, coa gene was detected in 61 (70.9%) of 86 S. aureus isolates. 10 different gene polymorphisms were detected in coa gene positive isolates. While the spa gene was determined in all S. aureus isolates, it was revealed that they had 4 spa gene polymorphisms. Nine different genotypes with a similarity between 51-75% were detected in the genotyping of vancomycin resistant 9 isolates. In conclusion, multiple antibiotic resistance rates in S. aureus isolates investigated were found to be important for mastitis treatment. The results obtained from this study show that milk and dairy products containing these factors pose a public health risk due to the determination of vancomycin resistance in mastitis-derived Staphylococcus strains.

A study of the effectiveness of a detergent-based California mastitis test (CMT), using Ethiopian and Nigerian domestic detergents, for the detection of high somatic cell counts in milk and their reliability compared to the commercial UK CMT

Background: The California mastitis test (CMT) is a simple cow-side indicator of the somatic cell count (SCC) in milk, providing a useful tool in identifying cases of subclinical mastitis in cattle. Mastitis, and in particular subclinical mastitis, is a major concern in Ethiopia and Nigeria, yet detection is challenging due to cost and access to commercial CMT reagents. Methods: Commercially available domestic detergents from Ethiopia and Nigeria were compared (n = 3 for each country) with the UK commercial CMT reagent in their ability to detect high SCC (>400,000 cells/ml milk). Sensitivity and specificity of the CMT test were calculated for the different detergents and positive and negative predictive values were established. Results: The average sensitivities of the tests ranged from 28-75% for the Ethiopian detergents and 68-80% for the Nigerian detergents, compared to 76% for the UK domestic detergent. Test specificities were 84-98%, 93-97% and 96%, respectively. Conclusions: Overall, the detergents demonstrated higher specificity than sensitivity. Nigerian detergents performed better than the Ethiopian products, however, the study identified suitable domestic detergents from both Ethiopia and Nigeria, comparable to the UK commercial CMT reagent, and we recommend their use as alternative CMT reagents for livestock-keepers to aid in cost-effective diagnosis of mastitis.

Genomic comparisons and phylogenetic analysis of mastitis-related staphylococci with a focus on adhesion, biofilm, and related regulatory genes

Mastitis is a common and costly disease on dairy farms, commonly caused by Staphylococcus spp. though the various species are associated with different clinical outcomes. In the current study, we performed genomic analyses to determine the prevalence of adhesion, biofilm, and related regulatory genes in 478 staphylococcal species isolated from clinical and subclinical mastitis cases deposited in public databases. The most prevalent adhesin genes (ebpS, atl, pls, sasH and sasF) were found in both clinical and subclinical isolates. However, the ebpS gene was absent in subclinical isolates of Staphylococcus arlettae, S. succinus, S. sciuri, S. equorun, S. galinarum, and S. saprophyticus. In contrast, the coa, eap, emp, efb, and vWbp genes were present more frequently in clinical (vs. subclincal) mastitis isolates and were highly correlated with the presence of the biofim operon (icaABCD) and its transcriptional regulator, icaR. Co-phylogenetic analyses suggested that many of these adhesins, biofilm, and associated regulatory genes could have been horizontally disseminated between clinical and subclinical isolates. Our results further suggest that several adhesins, biofilm, and related regulatory genes, which have been overlooked in previous studies, may be of use for virulence profiling of mastitis-related Staphylococcus strains or as potential targets for vaccine development.

Associations of udder biometry with subclinical mastitis in Gir crossbred cows

The investigation was undertaken on 110 Gir crossbred cows of different order of lactation and stage of lactation maintained at Research Cum Development Project on Cattle, MPKV, Rahuri. The overall least squares means of udder length, udder width, udder depth and udder circumference were 65.23 ± 1.45, 63.24 ± 1.45, 19.03 ± 0.51 and 86.49 ± 1.50 cm respectively. The least squares analysis of variance showed significant (P<0.05) effect due to order of lactation on udder length in crossbred cows. Also, order of lactation had significant (P<0.01) effect on udder width and udder circumference. However, stage of lactation exerted non-significant influence on all udder measurement traits. In crossbred cows udder length had positive and significant (P<0.01) correlation with udder width, udder circumference and udder depth. The correlation of udder width with udder circumference and udder depth was positive and highly significant (P<0.01). There was positive and significant (P<0.01) correlation of udder circumference with udder depth. The frequencies of trough, round, goaty and pendulous type udder in crossbred cows were 63.64%, 8.18%, 11.82% and 16.36% respectively. Among 110 cows 48 (43.64%) cows were found positive for subclinical mastitis. The higher occurrence of subclinical mastitis was observed in cows having pendulous udder (66.66%) followed by goaty (53.84 %), round (44.44 %) and trough (35.71 %) shape udder. Maximum number of positive subclinical mastitis cases were found in larger udder length (>75 cm), udder width (>75 cm), udder depth (>25 cm) and udder circumference (>95 cm). Highest occurrence (78.26%) of subclinical mastitis was found in cows of sixth and above lactation. Maximum occurrence of subclinical mastitis was noted in cows which were in late (46.15%) stage of lactation followed by early (40%) and mid (37%) stage of lactation. The traits udder shape, udder length and udder depth had positive and significant association with incidence of subclinical mastitis in crossbred cows.

Draft Genome Sequences of the Bap-Producing Strain Staphylococcus aureus V329 and Its Derived Phage-Resistant Mutant BIM-1

ABSTRACTThis study reports the draft genome sequences of Staphylococcus aureus V329, a Bap-producing strain isolated from a case of subclinical bovine mastitis in Spain, and a derived mutant (BIM-1) resistant to phage phiIPLA-RODI. Comparison of the two genomes revealed that the mutant strain has a point mutation in the gene tagO.

Detecção de β-lactamase, blaZ e mecA em amostras de Staphylococcus aureus resistentes à penicilina isoladas de mastite bovina em Garanhuns, Brasil

There are few reports in the literature about genetic determinants of resistance to β-lactams in Staphylococcus aureusisolated from dairy cattle located in the municipality of Garanhuns, state of Pernambuco, Brazil. Thus, this study aimed to investigate the production of β-lactamase and the presence of the blaZ and mecA genes in penicillin-resistant S. aureus isolated from cases of subclinical bovine mastitis in the city of Garanhuns. Forty-six strains of penicillin-resistant S. aureus were evalu-ated using the nitrocefin disc test and duplex PCR. The results revealed that 45 strains (97.8%) were positive for β-lactamase production and 44 (95.7%) carried the blaZ gene. Among the latter, 43 (97.7%) were β-lactamase producers and only one (2.3%) was not. The mecA gene was not detected in any of the isolates investigated. The results suggest that enzymatic inacti-vation is the main β-lactam resistance mechanism expressed by S. aureus in the herds analyzed.

Prevalence, Isolation, Identification, and Risk Factors of Major Bacterial Cause of Camel Subclinical Mastitis.

Objective A crosssectional study was conducted between September 2015 and August 2016 in the district of Afar Regional State, Northeastern Ethiopia, to characterize the most prevalent bacterial pathogens and identify the associated risk factors of camel subclinical mastitis. California mastitis test (CMT) was used as a screening test, and standard bacteriological methods were carried out for isolation and identification of the pathogens. Results Among the total 96 lactating camels examined, 25 were found positive with the overall prevalence of 26%, with 25% and 1% subclinical and clinical mastitis cases, respectively. Totally, 384 quarters of udder were examined; of these, 10 of them were blind while the rest 374 were nonblind teats. The quarter level prevalence of subclinical mastitis was 8.9%. The analysis showed that statistically significant difference (P < 0.05) of tick infestation and subclinical mastitis. Additionally, among the bacteriologically tested 34 CMT positive milk samples, all of them showed growth on nutrient and blood agar plate. Out of these culture isolates, the major bacterial pathogens identified were Staphylococcus aureus (8.7%), Staphylococcus hyicus (6.52%), Staphylococcus intermedius (6.52), Coagulase-negative staphylococci (19.57%), Bacillus (19.57%), Escherichia coli (6.52%), and Pasteurella multocida (6.52%) species. Therefore, appropriate control measures and awareness creation to the community should be practiced.

Milk and serum proteomes in subclinical and clinical mastitis in Simmental cows

Bovine mastitis causes changes in the milk and serum proteomes. Here changes in both proteomes caused by naturally occurring subclinical and clinical mastitis have been characterised and quantified. Milk and serum samples from healthy dairy cows (n = 10) were compared to those of cows with subclinical (n = 12) and clinical mastitis (n = 10) using tandem mass tag (TMT) proteomics. Proteins that significantly increased or decreased in milk (n = 237) or serum (n = 117) were quantified and classified by the type of change in subclinical and clinical mastitis. A group of the proteins (n = 38) showed changes in both milk and serum a number of which decreased in the serum but increased in milk, suggesting a particular role in host defence for maintaining and restoring homeostasis during the disease. Proteins affected by bovine mastitis included proteins in host defence and coagulation pathways. Investigation of the modified proteomes in milk and serum was assessed by assays for haptoglobin, serum amyloid A and α1 acid glycoprotein validating the results obtained by quantitative proteomics. Alteration of abundance patterns of milk and serum proteins, together with pathway analysis reveal multiple interactions related to proteins affected by mastitis. Data are available via ProteomeXchange with identifier PXD022595. SignificanceMastitis is the most serious condition to affect dairy cows and leads to reduced animal welfare as well as having a negative economic effect for the dairy industry. Proteomics has previously identified changes in abundance of milk proteins during mastitis, but there have been few investigations addressing changes that may affect proteins in the blood during the infection. In this study, changes in the abundance of proteins of milk and serum, caused by naturally occurring mastitis have been characterised by proteomics using a quantitative approach and both subclinical and clinical cases of mastitis have been investigated. In both milk and serum, change in individual proteins was determined and classified into varying types of altering abundance, such as increasing in subclinical mastitis, but showing no further increase in clinical mastitis. Of special interest were the proteins that altered in abundance in both milk and serum which either showed similar trends - increasing or decreasing in both biological fluids or showed reciprocal change decreasing in serum but increasing in milk. As well as characterising proteins as potential markers of mastitis and the severity of the disease, these results provide insight into the pathophysiology of the host response to bovine mastitis.

Diagnosis of clinical and subclinical mastitis in a rural property in Carambeí, State of Paraná

The aim of the present study was to diagnose clinical and subclinical bovine mastitis in a property in the municipality of Carambeí-PR. 86 dairy cows were diagnosed in two evaluations carried out on July 23 and November 4, 2020. The detection of clinical mastitis was performed by testing the black-bottomed mug, whereas the detection of animals with sub-clinical mastitis by the California Mastitis Test (CMT) and laboratory analysis of bacteria and fungi present. In the first evaluation, 9.4% of the animals had mastitis, while in the second 5.16% of the herd. The milk of the animals that tested positive were submitted to laboratory analysis. In the first evaluation, they were diagnosed with an incidence of 15% Escherichia coli, 15% Prothoteca / yeast, 23% Staphlococcus aureus, 46% Streptococcus agalactiae. In the second evaluation, there was an incidence of 25% Enterococcus sp. and 25% S. agalactiae, the other animals showed 50% Staphlococcus non aureus. There was a higher occurrence of subclinical mastitis in the property, in both evaluations. There was a reduction from the first to the second evaluation in the incidence of cases of subclinical mastitis and the cases of clinical mastitis were resolved. Contributing to the lower disposal of milk caused by the high somatic cell count.