Staphylococcus chromogenes TA showed significantly lower growth under iron-deprived conditions, and adding an iron supplement (lactoferrin or ferritin) resulted in no improvement in growth; in contrast, growth of S. chromogenes IM was significantly recovered with ferritin iron supplementation. OnlyStaphylococcus hominis strains originating from quarter milk were able to significantly utilize ferritin as an iron source to reverse the growth inhibition caused by chelating agent 2,2'-bipyridyl in varying degrees. Both S. chromogenes strains (IM and TA) and all S. hominis strains were unable to significantly use lactoferrin as an iron source for growth recovery.
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http://dx.doi.org/10.3168/jds.2024-107-3-1821 | DOI Listing |
Sci Rep
December 2024
Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, SAR, China.
The emergence of pandrug-resistant (PDR) and extensive drug-resistant (XDR) methicillin-resistant and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) isolates from bovine milk samples along with biofilm formation ability and harboring various virulence genes complicates the treatment of bovine mastitis and highlights the serious threat to public health. This study investigated for the first time the frequency, antimicrobial resistance profiles, biofilm-forming ability, virulence factors, spa and staphylococcal cassette chromosome mec (SCCmec) types of MRSA and VRSA isolated from clinical and subclinical bovine mastitis in Egypt. A total of 808 milk samples were collected from each quarter of 202 dairy animals, including 31 buffaloes and 171 cattle.
View Article and Find Full Text PDFJ Dairy Sci
December 2024
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada; Regroupement FRQNT Op+lait, Saint-Hyacinthe, QC, Canada. Electronic address:
Microbial infections of the mammary gland often cause mastitis, and it can lead to substantial economic losses within the dairy industry due to its direct negative impact on milk production and composition and the associated treatment costs. Somatic cell count has emerged as a critical indicator in monitoring udder health, and recently, the large-scale availability of differential cell count analysis potentially offers new insights into underlying physiological processes. Therefore, the main objective of this study was to estimate the variation of DSCC and SCC of individual quarter-level milk samples of cows according to 1) their intramammary infectious status; 2) parity of the cow; 3) quarter location; and 4) DIM at the time of sampling.
View Article and Find Full Text PDFJ Dairy Sci
December 2024
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada; Regroupement FRQNT Op+lait, Saint-Hyacinthe, QC, Canada. Electronic address:
Mastitis, an inflammation of the udder primarily caused by an intramammary infection, is one of the most common diseases in dairy cattle. Somatic cell count (SCC) has been widely used as an indicator of udder inflammation, assisting in the detection of subclinical mastitis. More recently, differential somatic cell count (DSCC), which represents the combined proportion of lymphocytes and polymorphonuclear leukocytes, has become available for routine dairy milk screening, though it was not yet widely studied.
View Article and Find Full Text PDFJ Dairy Sci
December 2024
Department of Animal and Veterinary Sciences, University of Vermont, Burlington, VT 05405. Electronic address:
Variation in species distribution and diversity of staphylococci and mammaliicocci (SaM) causing intramammary infections in dairy cattle is associated with different management practices. Disparate selective pressures on organic dairies could potentially result in population differences of these mastitis-causing bacteria. The species-specific effect on quarter somatic cell count of SaM for a population of certified organic dairies has not been described previously.
View Article and Find Full Text PDFJ Dairy Sci
December 2024
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, Saint-Hyacinthe, QC, Canada; Regroupement FRQNT Op+lait, Saint-Hyacinthe, QC, Canada. Electronic address:
Mastitis poses significant economic challenges for dairy farms. Therefore, enhancing the accuracy of diagnostic methods for detecting intramammary infections (IMI) can potentially improve prevention, control and treatment strategies. The somatic cell count (SCC) is a well-established parameter for identifying inflammation resulting from IMI.
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