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Cystathionine-β-synthase (CBS) catalyzes the first step of the transsulfuration pathway. The role of host-derived CBS in Staphylococcus aureus (S. aureus) - induced udder infection remains elusive. Herein, we report that S. aureus infection enhances the expression of CBS in mammary epithelial cells in vitro and in vivo. A negative correlation is present between the expression of CBS and inflammation after employing a pharmacological inhibitor/agonist of CBS. In addition, CBS achieves a fine balance between eliciting sufficient protective innate immunity and preventing excessive damage to cells and tissues preserving the integrity of the blood-milk barrier (BMB). CBS/H 2 S reduces bacterial load by promoting the generation of antibacterial substances (ROS, RNS) and inhibiting apoptosis, as opposed to relying solely on intense inflammatory reactions. Conversely, H 2 S donor alleviate inflammation via S-sulfhydrating HuR. Finally, CBS/H 2 S promotes the expression of Abcb1b , which in turn strengthens the integrity of the BMB. The study described herein demonstrates the importance of CBS in regulating the mammary immune response to S. aureus. Increased CBS in udder tissue modulates excessive inflammation, which suggests a novel target for drug development in the battle against S. aureus and other infections. [Display omitted] • S. aureus infection in the udder results in an increase in CBS. • CBS plays a role in the negative regulation of inflammation. • CBS contribute to maintain BMB integrity via promoting Abcb1b expression. [ABSTRACT FROM AUTHOR]

The effect of acoustic pulse technology (APT) on recovery, culling, milk yield, and economic benefits for 118 cows with subclinical mastitis was compared with a no-treatment control (59 vs. 59), and another 118 APT-treated cows with clinical mastitis were compared with antibiotic-treated controls (59 vs. 59). Recovery was defined as a decrease in somatic cell count (SCC) to 3 cells/mL in at least two out of three monthly milk recordings after treatments. For the subclinically infected cows, APT treatment resulted in 65.5% recovery, 0% culling, and additional milk yield of 2.74 L/cow per day compared to 35.6% recovery and 5.1% culling in the no-treatment controls. For the clinically infected cows, APT treatment resulted in 67.8% recovery, 6.8% culling, and additional milk yield of 3.9 L/cow per day compared to 35.6% recovery and 32.2% culling in the antibiotic-treated group. Bacteriological analysis was run for 95 (80%) cows with clinical mastitis (APT-46; AB-49). For cows with Escherichia coli infection, 85.7% (18/21) treated with APT recovered vs. 17.6% (3/17) in the antibiotic-treated group; for cows with streptococcal infection, 66.0% (12/18) in the APT-treated group recovered vs. 44.4% (8/18) in the antibiotic-treated group.

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Mastitis is an important constraint to milk production in pastoralist camel (Camelus dromedarius) herds in Kenya. The objective of this study was to investigate the prevalence, risk factors, and bacterial panorama of subclinical mastitis (SCM) in pastoralist camel herds in Isiolo County, Kenya. Furthermore, antimicrobial susceptibility in udder pathogens was studied. A cross-sectional sample of 206 camels from 20 milking herds was screened using the California Mastitis Test (CMT), and quarter milk was subjected to bacterial culturing. Isolates were confirmed using MALDI-TOF mass spectrometry analysis, and antimicrobial susceptibility was determined using the broth microdilution method. Interviews focusing on herd management were conducted with camel owners. Subclinical mastitis, defined as a CMT score ≥ 3 (scale 1 to 5) and absence of clinical symptoms in the udder, were present in all visited herds. On the individual level, 46% of the camels had at least 1 quarter affected with SCM, and on the quarter level the prevalence was 26%. Intramammary infections (IMI) were common; out of 798 quarter milk samples, 33% yielded conclusive bacterial growth. The sensitivity and specificity of CMT for correctly identifying quarters with IMI were 82% and 92%, respectively. The most prevalent pathogen was Streptococcus agalactiae (72% of IMI-positive quarters), followed by non-aureus staphylococci (19%) and Staphylococcus aureus (13%). Antimicrobial susceptibility testing revealed that only a low proportion (4.9%) of Strep. agalactiae isolates was sensitive to tetracycline. For Staph. aureus , 59.1% of isolates exhibited sensitivity to penicillin. Skin lesions on the teats or udder were a risk factor for SCM. Increased age, parity, and stage of lactation were associated with increased risk of both SCM and IMI. Older camels with a blind teat or a previous history of mastitis were more likely to be infected with Strep. agalactiae. Hygiene routines for milking were largely absent in the observed herds, and knowledge of adequate milk handling was limited. The poor udder health is likely to depend on multiple factors, most prominently the within-herd maintenance of contagious udder pathogens, in combination with difficult sanitary conditions and lack of awareness among camel keepers. This study showed that in pastoralist camel herds around Isiolo town, SCM and IMI specifically caused by Strep. agalactiae are common udder health problems and are associated with increasing age, parity, and stage of lactation, and skin lesions on the teats and udder. Resistance to tetracycline in Strep. agalactiae was common. Control strategies specifically targeting SCM and adapted to pastorally managed camel herds need to be developed to reduce disease, combat antimicrobial resistance, and improve the livelihoods of pastoralists. [ABSTRACT FROM AUTHOR]

Dairy production is not traditional in Vietnam. The farmers have little practical knowledge and udder health control is generally lacking. In order to give the farmers appropriate advice, knowledge about the distribution of udder pathogens is crucial. The aim of the study was to investigate the prevalence of sub-clinical mastitis and to identify udder pathogens isolated from smallholder dairy herds in Southern Vietnam. Twenty farms with a herd somatic cell count (SCC) ranging from low (≤400 × 10 cells/mL) to high (>400 × 10 cells/mL) were randomly selected. Milk samples were collected from 458 quarters of 115 clinically healthy cows. SCC was analyzed on farm by a portable cell counter. Bacteriological samples were taken using Mastistrip cassettes and sent to Sweden for examination. For all herds the mean herd SCC was 632 × 10/mL milk. The prevalence of subclinical mastitis at quarter SCC basis was 63.2 % and at cow basis 88.6 %. Only 40 % of all cows were bacteriologically negative in all quarters. Streptococcus agalactiae was the most commonly found bacteria species, isolated from 96 of the 458 quarter samples, in 13 of the 20 farms. The results indicate pronounced subclinical mastitis problems among the dairy cows in this region mainly due to infections with S. agalactiae. The high prevalence of this highly contagious pathogen is probably attributable to the generally poor milking hygiene and low awareness of proper measures to prevent occurrence and spread of udder infections. A strict, targeted action program for the herds in this area is required in order to lower the prevalence of subclinical mastitis. [ABSTRACT FROM AUTHOR]

Abstract: Udder infections in dairy cows are observed at udder quarter level. Therefore, the best strategy to study infection dynamics of particular bacteria causing mastitis is to follow up and model individual udder quarter infection times. Udder quarter infection times, however, are not independent as they are clustered within a cow and herds. Another challenge in modelling infection times is that the exact infection time is unknown; it is only known that the infection has taken place in the interval between the last negative and the first positive sample. We applied a technique based on the gamma frailty model which handles the clustering and interval censoring simultaneously. Parameter estimates can be obtained analytically and their variance is obtained by the inverse of the hessian matrix. The proposed technique was applied to udder quarter infection times for Corynebacterium bovis, Staphylococcus aureus and Streptococcus uberis. Multiparous cows were more likely to get infected earlier in lactation with C. bovis or S. uberis than primiparous cows. The times to infection of all three bacteria were highly clustered at cow level and the results of a stratified model on a subset of herds suggested a high clustering on herd level for C. bovis and S. uberis. [Copyright &y& Elsevier]

Staphylococcus aureus is an important pathogen for both humans and animals, and it has been an ubiquitous etiological agent of bovine mastitis in dairy farms worldwide. Elimination of S. aureus with classic antibiotics is difficult, and the current study aimed to evaluate the efficacy of ethanolic extracts of propolis (EEP) against S. aureus cultivated in complex media or milk. EEP (0-0.5 mg ml) decreased growth of S. aureus in BHI media and 1 mg ml was bactericidal against washed cell suspensions (10 CFU ml). Propolis extracts also killed S. aureus cells resuspended in milk, but the bactericidal dose was at least 20-fold greater. Cultures that were transferred for at least 60 generations with sub-lethal doses of propolis did not change much their sensibility to EEP. Atomic force microscopy images revealed changes in morphology and cell size of S. aureus cells exposed to EEP (0.5 mg ml). Our results indicate that propolis extracts might be effective against mastitis-causing S. aureus strains in vivo, but milk constituents affect the inhibitory activity of propolis. Considering that propolis-resistance appears to be a phenotype not easily selected, the use of EEP combined or not with other antimicrobial agents might be useful for mastitis control in vivo. [ABSTRACT FROM AUTHOR]

Abstract: Equations for predicting milk and curd loss due to intramammary infection in sheep and goat herds were derived. The empirical equations were derived from previously published studies conducted by this team with Assaf sheep and crossbreeds of goats in Israel. From these equations, it appears that infection of 25, 50 and 75% of the udders in a given herd was associated with loss of 4.1–12.2.5% milk in sheep and 0.8–2.3% in goats; whereas curd loss was 5.2–15.5% in sheep and 3.3–9.8.9% in goats. Based on percent of udder infection and projected SCC, the following categories are suggested for classification of sheep and goat milk: i. High-quality milk <800,000SCC/mL, associated with infection of ∼25%; ii. Medium quality milk <1,500,000SCC/mL, associated with infection rate between 25 and 50%; iii. Low-quality milk >1,500,000SCC/mL, associated with infection rate above 50%; iv. Milk containing >3,500,000SCC/mL should not be accepted for human consumption. [Copyright &y& Elsevier]

Abstract: The effects of separate infection with four major pathogens frequently associated with the occurrence of subclinical mastitis in cows (Staphylococcus aureus, S. chromogenes, Escherichia coli and Streptococcus dysgalactiae) on milk quality for cheese production were studied for quarters of the same animal. Infection increased somatic cell count (SCC), modified leucocyte distribution, decreased lactose concentration and increased proteolysis of casein. Regardless of bacteria type, the plasmin activity in milk from the infected glands increased ∼2 fold compared with uninfected quarters. These changes were associated with increased rennet clotting time and decreased curd firmness for milk from infected glands, indicating that milk quality for cheese production was negatively affected by infection. Although the general pattern of bacterial invasion was similar, each type of bacteria elicited the above-described responses in a specific manner. SCC, commonly used by the dairy industry as a measure of milk hygienic quality, provided the poorest prediction of milk quality for cheese production in comparison to indices of proteolysis of casein. [Copyright &y& Elsevier]

The present study focused on gaining a better insight into how subclinical mastitis at the gland level in dairy sheep and goats affects milk yield and compositional changes in relation to curd yield. Animals chosen for the study had one udder half infected with identified coagulase-negative staphyloccocci (CNS) species and the contralateral gland was free of bacteria. Udder halves were tested for udder bacterial condition, California mastitis test, somatic cell count (SCC), milk yield, milk composition (fat, protein, lactose, casein (CN), and whey protein), curd yield (Yc) and milk clotting time (Tc). Data were statistically analyzed with a nested block design. Curd yield from the infected halves was lower than that from the uninfected ones for both sheep and goats, although CN concentrations were almost equal in the two glands. The data suggest that knowledge of the gross CN content in the milk is insufficient for predicting Yc, probably because of modifications in the CN micelles or in the various casein micelle components that are more detrimental to curd formation than they are to the CN concentration itself. The primary enzymatic coagulation is based on the action of rennin on κ-casein, which thereafter exposes hydrophobic sites on the casein micelle, thus making it available for the secondary aggregation reaction. The complications in the coagulation process are also supported by the longer Tc of the milk from the infected glands. However, the effect of rennet on the caseins and thereafter the coagulation process may be impeded by only partial hydrolysis of κ -casein and more pronounced hydrolysis of the other caseins by enzymes such as PL and cathepsin. [ABSTRACT FROM AUTHOR]

The present study aimed to analyze the major factors that influence milk yield in Assaf sheep and Saanen, and Shami x Anglo Nubian goats, the major small ruminant dairy breeds and crossbreds in Israel. Six different farms with 745 Israeli-Assaf dairy sheep and 682 goats were surveyed. Udder halves were tested for udder bacterial condition, California mastitis test (CMT), somatic cell count (SCC), N-acetyl-β -D-glucosaminidase (NAGase) activity and milk composition (fat, protein and lactose). Effects of subclinical mastitis caused by CNS include a drastic increase in SCC and a decrease in milk yield. Changes are more acute in sheep compared with goats: SCC was quadrupled and milk yield was decreased by 30% in sheep, and in goats SCC was doubled and milk yield was only slightly decreased. However, in both sheep and goats, the direct income loss from decreased milk yield and the strong immune response to bacterial udder contamination, which results in the increase of SCC, appear to be of much greater magnitude than noted in dairy cows. The implication of these results is that for a given percentage of animals with udders contaminated with CNS, the increase in SCC will be much higher in the bulk milk of dairy sheep than cows. In dairy sheep and goats, grading milk according to SCC as currently practiced in herd improvement programs will place great pressure on growers to produce milk of a higher quality. [ABSTRACT FROM AUTHOR]