Antimicrobial resistance of Streptococcus uberis isolated from bovine mastitis: Systematic review and meta-analysis.

Streptococcus uberis is one of the most common pathogens associated with bovine mastitis, commonly treated with antimicrobials (AM), favoring the appearance of antimicrobial resistance (AMR). The objective of this work was to determine the proportion of phenotypic AMR among S. uberis isolated worldwide from bovine intramammary infections between the years 1983-2022, and to assess the variables associated by means of a systematic review and metanalysis.

Detection by multiplex PCR of Mycoplasma species associated with dairy cattle in Argentina.

There is scarce information about the frequency and epidemiological and clinical features associated with the presence of Mycoplasma spp. in Argentine dairy herds. The objectives of this study were to develop a multiplex PCR for identifying M.

Efficacy of extract combined with cephalexin as a dry cow therapy.

Our objective was to evaluate the efficacy of intramammary administration, at drying-off, of a Panax ginseng extract (PGe) combined with cephalexin (Ceph) on the post-calving bacteriological cure rate of pre-existing intramammary infections (IMI) and on the occurrence of new IMI during the dry period. In addition, milk yield and somatic cell count (SCC) in the post-treatment lactation were evaluated. One hundred and eight late-lactation cows were randomly divided into two experimental groups and were treated at drying-off with Ceph alone or PGe combined with Ceph.

Antimicrobial resistance of Staphylococcus aureus isolated from bovine mastitis: Systematic review and meta-analysis.

Staphylococcus aureus, one of the main contagious mastitis pathogens worldwide, is characterized for causing chronic intramammary infections that respond poorly to antimicrobial therapy, disseminating within the herd leading to high economic losses. The aim of this study was to determine the prevalence of phenotypic resistance to antimicrobial agents among S. aureus collected worldwide in the context of bovine intramammary infections between the years 1969-2020.

Risk factors of intramammary infection in pre partum dairy heifers under grazing conditions and molecular characterization of isolates from heifers and cows.

The aims of the research reported here were to identify potential risk factors associated with the presence of Staphylococcus aureus intramammary infection (IMI) in pre partum dairy heifers on 17 dairy farms from three provinces of Argentina and to characterize, at molecular level, isolates from those heifers and lactating cows from two selected herds. A total of 1474 heifers and 4878 lactating cows were studied. The prevalence of Staphylococcus aureus IMI in the heifers, heifers at quarter level and lactating cow mammary quarters was 14.

Combined Metagratings for Efficient Broad-Angle Scattering Metasurface.

Spectrally controlled diffusion and reflection of light are key operations for light management in many optical devices. Integration of this operation in complex nanophotonic devices requires a 2D interface that provides tailored spectrum and directivity control. Here, we present a metagrating superstructure that realizes a resonant light reflector with tailored angular scattering profile.

First report of Mycoplasma leachii isolation associated with disease in dairy calves in Argentina.

There are few reports about the isolation of Mycoplasma species associated with cattle disease in Argentina. In this work we describe the detection of Mycoplasma leachii associated with disease in dairy calves in Santa Fe Province, Argentina. Samples obtained from a 4 day-old dairy calf suffering from polyarthritis and from two other calves, one with arthritis and the other one with a mandibular abscess, were subjected to microbiological culture.

Comparison of phenotypic tests for detecting penicillin G resistance with presence of blaZ gene in Staphylococcus aureus isolated from bovine intramammary infections.

Few studies have described the relationship between genotypic and phenotypic methods for detecting penicillin resistance in Staphylococcus aureus isolated from bovine intramammary infection (IMI). Six phenotypic methods for penicillinase detection were compared with a genotypic method testing the presence of the β-lactamase gene blaZ in Staph. aureus (n = 150) isolated from bovine IMI.

Association between milking practices and psychrotrophic bacterial counts in bulk tank milk.

The objective of this work was to determine on-farm risk factors for psychrotrophic bacterial counts in bulk tank milk from dairy farms in Argentina. Raw milk samples from bulk tanks of 27 dairy farms were examined for total psychrotrophic counts (TPC), proteolytic psychrotrophic counts (PPC) and lipolytic psychrotrophic counts (LPC) (dependent or outcome variables). A survey recording infrastructure conditions, milking equipment and milking management (independent variables) was performed.

Proinflammatory cytokines and CD14 expression in mammary tissue of cows following intramammary inoculation of Panax ginseng at drying off.

The lack of efficacy of conventional strategies for the maintenance of healthy udders in domestic cattle has prompted studies on the use of immunomodulators or biological response modifiers (BRM) for this purpose. These compounds are agents that modify the host's response to pathogens leading to beneficial effects on disease outcome. The objective of this study was to evaluate the effects of a single intramammary infusion of Panax ginseng (GS) extract on the amount of pro-inflammatory cytokines and the number of monocytes/macrophages present in bovine mammary tissues at drying off.

Presence of enterotoxigenic Staphylococcus aureus in bulk tank milk from Argentine dairy farms.

Staphylococcus aureus is the most prevalent bovine mastitis pathogen in Argentina. The ability of this organism to produce enterotoxins is linked to staphylococcal food poisoning. Staphylococcal enterotoxins are low molecular weight proteins, highly resistant to heat and proteolytic enzyme activity.

Intramammary inoculation of Panax ginseng extract in cows at drying off enhances early mammary involution.

This study was designed to evaluate the effects of a single intramammary infusion of Panax ginseng extract on cell proliferation and death mechanism in bovine mammary gland during early involution. Eight mammary quarters from six non-pregnant cows in late lactation were infused with 10 ml of ginseng solution (3 mg/ml), six quarters were treated with 10 ml of placebo (vehicle alone) and six quarters were maintained as uninoculated controls. Milking was interrupted after infusion.

Effect of Panax ginseng on cytokine expression in bovine mammary glands at drying off.

Biological response modifiers (BRM) are agents that modify the host's response to pathogens with resultant beneficial prophylactic or therapeutic effects. The objectives of this study were to describe the immunomodulatory effects of Panax ginseng (GS) on bovine mammary glands at the end of lactation. Eight mammary quarters from six nonpregnant cows in late lactation were infused with 10mL of BRM (3mg/mL), six quarters were treated with placebo (vehicle alone) and six quarters were maintained as uninoculated controls.

Effect of a biological response modifier on expression of CD14 receptor and tumor necrosis factor-alpha in Staphylococcus aureus-infected mammary glands at drying off.

Agents that increase natural protective mechanisms have been proposed for prevention and treatment of intramammary infections. The objectives of this study were to get an insight of innate immune mechanisms that occur during bovine mammary involution in both uninfected and chronically Staphylococcus aureus-infected glands and to describe the effects on those mechanisms of a single intramammary infusion of a LPS-based biological response modifier (BRM) at the end of lactation. Three groups of 12 cows, each one including 6 S.

Intramammary infections during the periparturient period in Argentine dairy heifers.

Prevalence of intramammary infections at prepartum and postpartum in primigravid heifers from five dairy herds located in the central dairy area of Argentina was determined. Mammary secretion samples from 140 heifers (560 mammary quarters) were obtained 14 days prior to the expected calving day and within 7 days after parturition and subjected to bacteriological analysis. No clinical mastitis cases were detected during the study.

[Antimicrobial sensitivity of coagulase-positive staphylococcal strains isolated from bovine mastitis in the central dairy catchment area of Argentina ].

The activity of antimicrobial agents frequently used for treating bovine mastitis was determined against 101 coagulase-positive staphylococci isolated from bovine mammary secretion. The isolates were obtained from 39 dairy farms located in the central dairy area of Argentina. The disk diffusion method was used and the following antimicrobial agents were tested: penicillin, ampicillin, oxacillin, cephacetrile, penicillin + novobiocin, erythromycin, pirlimycin, novobiocin and neomycin.