Sarne De Vliegher

Sarne De Vliegher
Ghent University | UGhent · Department of Internal Medicine, Reproduction and Population Medicine

DVM MSc PhD Dipl ECVPH

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345
Publications
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Publications

Publications (345)
Article
Full-text available
Mastitis bij vleesschapen is een ernstige ziekte die vaak fataal is. In dit onderzoek wordt het voorkomen van de ziekte beschreven met klemtoon op de predisponerende factoren. Aan Vlaamse en Nederlandse schapenhouders werd in een enquête gevraagd of predisponerende factoren al dan niet aanwezig zijn op hun bedrijf, alsook werd hun kennis van mastit...
Article
Administering intramammary antimicrobials to all mammary quarters of dairy cows at drying-off [i.e., blanket dry cow therapy (BDCT)] has been a mainstay of mastitis prevention and control. However, as udder health has considerably improved over recent decades with reductions in intramammary infection prevalence at drying-off and the introduction of...
Article
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In this paper, we describe a new quantitative method to evaluate and quantify in vitro growth inhibition of mastitis-related bacteria. Colony-forming units of Staphylococcus (S.) aureus (n = 10), Escherichia (E.) coli (n = 10), and Streptococcus (S.) uberis (n = 10) were quantified after their growth on top of layers of trypticase soy agar (TSA) co...
Article
Full-text available
Staphylococci are among the commonly isolated bacteria from intramammary infections in bovines, where Staphylococcus aureus is the most studied species. This species carries a variety of virulence genes, contributing to bacterial survival and spread. Less is known about non- aureus staphylococci (NAS) and their range of virulence genes and mechanis...
Article
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Although extensive research has been performed on bovine non- aureus staphylococci (NAS), several aspects such as bacteria-host interaction remain largely unstudied. Moreover, only a few mastitis pathogen challenge studies in cows have been conducted in the dry period, an important period that allows intramammary infection (IMI) to cure and new IMI...
Article
Full-text available
Mastitis affects a high proportion of dairy cows and is still one of the greatest challenges faced by the dairy industry. Staphylococcal bacteria remain the most important cause of mastitis worldwide. We investigated how distinct staphylococcal species evade some critical host defense mechanisms, which may dictate the establishment, severity, and p...
Article
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Biofilm formation is a significant virulence factor in Staphylococcus (S.) aureus strains causing subclinical mastitis in dairy cows. A role of environmental signals and communication systems in biofilm development, such as the agr system in S. aureus, is suggested. In the context of multispecies biofilm communities, the presence of non-aureus stap...
Chapter
In this chapter several aspects of udder health are discussed. Mastitis, inflammation of the mammary gland, which is generally caused by bacterial infections, is one of the most important and most studied diseases in dairy cattle. Diagnostic approaches are discussed with specific attention for the bacteriological causes of the disease. Subsequently...
Article
Mastitis-associated milk losses in dairy cows have a massive impact on farm profitability and sustainability. In this study, we analyzed milk losses from 4 553 treated mastitis cases as recorded via treatment registers at 41 AMS dairy farms. Milk losses were estimated based on the difference between the expected and the actual production. To estima...
Article
Full-text available
Communications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We determined whether 34 S. chromogenes, 11 S. epidermidis, and 14 S. simulans isolates originating from bovine milk samples and teat apices were able to regulate the QS of S. aureus, a...
Article
Full-text available
Despite considerable efforts to control bovine mastitis and explain its causes, it remains the most costly and common disease of dairy cattle worldwide. The role and impact of non-aureus staphylococci (NAS) in udder health are not entirely understood. These Gram-positive bacteria have become the most frequently isolated group of bacteria in milk sa...
Article
Full-text available
Mastitis is a prevalent disease in dairy cattle, and staphylococci are among the most common causative pathogens. Staphylococci can express resistance to a range of antimicrobials, of which methicillin resistance is of particular public health concern. Additionally, Staphylococcus aureus carries a variety of virulence factors, although less is unde...
Article
Full-text available
Staphylococcus chromogenes is a common skin commensal in cattle and has been identified as a frequent cause of bovine mastitis and intramammary infections. We have developed a seven locus Multilocus Sequence Typing (MLST) scheme for typing S . chromogenes . Sequence-based typing systems, such as MLST, have application in studies of genetic diversit...
Article
Full-text available
The presence of non-aureus staphylococci (NAS) in bovine rectal feces has recently been described. Similar to other mastitis causing pathogens, shedding of NAS in the environment could result in intramammary infection. The objective of this study was to investigate whether NAS strains present in feces can cause intramammary infection, likely via te...
Preprint
Full-text available
Staphylococcus chromogenes is a common skin commensal in cattle and has been identified as a frequent cause of bovine mastitis and intramammary infections. To better understand the extent of strain diversity within this species and to facilitate study of strain variation as a factor in pathogenicity, we have developed a seven locus Multilocus Seque...
Article
Milk yield dynamics during perturbations reflect how cows respond to challenges. This study investigated the characteristics of 62,406 perturbations from 16,604 lactation curves of dairy cows milked with an automated milking system at 50 Belgian, Dutch, and English farms. The unperturbed lactation curve representing the theoretical milk yield dynam...
Article
We conducted a longitudinal study to evaluate the effect of non-aureus staphylococci (NAS) causing subclinical intramammary infections (IMI) on quarter milk somatic cell count (qSCC) and quarter milk yield (qMY). In total, 324 quarters of 82 Holstein Friesian heifers were followed from calving to 130 d in milk (DIM) and were sampled 10 times each a...
Article
Full-text available
Intramammary infections (IMI) with Staphylococcus aureus are a common cause of bovine mastitis and can result in both clinical (CM) or subclinical mastitis (SCM). Although bacterial isolates of S. aureus differ in their virulence potential it is largely unclear which bacterial virulence factors are responsible for increased clinical severity. We pe...
Article
Non-aureus staphylococci (NAS) are predominantly isolated from bovine milk samples of quarters suffering from subclinical mastitis. They are also abundantly present on dairy cows' teat apices and can be recovered from bovine fecal samples, as recently described. Differences in ecology, epidemiology, effect on udder health, and virulence or protecti...
Preprint
Full-text available
Milk yield dynamics during perturbations reflect how cows respond to challenges. This study investigated the characteristics of 62,406 perturbations from 16,604 lactation curves of dairy cows milked with an automated milking system at 50 Belgian, Dutch and English farms. The unperturbed lactation curve representing the theoretical milk yield dynami...
Article
Full-text available
Objectives The aim of this study was to assess the efficacy of lytic bacteriophages onStaphylococcus aureus causing bovine mastitis, by in vitro and in vivo assays using Galleria mellonella and murine mastitis models. Methods Between May and December 2016, tenS. aureus (five methicillin-resistant and five methicillin-sensitive) isolates were isola...
Article
The main objective of this study was to evaluate the barrier characteristics of 3 external teat sealants for dry cows in preventing bacterial penetration by 3 common major mastitis pathogens (Escherichia coli, Staphylococcus aureus, and Streptococcus uberis) via a novel in vitro simulation model using rubber calf-feeding nipples. All feeding nipple...
Article
We analyzed a large number of immune response parameters from quarter milk samples with distinct bacteriological and quarter somatic cell count (qSCC) statuses. Furthermore, we sought to explore and identify displayed immune response patterns in milk samples from mammary glands with nonspecific mastitis. Thus, 92 quarter milk samples from 28 cows w...
Article
Full-text available
The objective of this study was to investigate the new differential somatic cell count (DSCC) as a supplementary indicator to SCC for the identification of intramammary infection (IMI) in dairy cows at the end of the lactation period. Different approaches for identification of cows with IMI (i.e. often based on SCC) and targeted antimicrobial treat...
Article
Full-text available
RESUMO O objetivo do presente estudo foi avaliar a capacidade de estafilococos não aureus (NAS) isolados de diferentes nichos ecológicos (leite, ambiente e ápice do teto), associados a vacas leiteiras, de inibir os principais agentes etiológicos da mastite bovina (Staphylococcus aureus, Streptococcus agalactiae, Streptococcus uberis e Escherichia c...
Article
This longitudinal study aimed to evaluate the impact of subclinical intramammary infection (IMI) with non-aureus staphylococcal (NAS) species in the first 18 d in milk (DIM) on the quarter milk somatic cell count (qSCC) and quarter milk yield (qMY) during the first 4 mo of lactation in Holstein Friesian heifers. Quarter milk samples were collected...
Article
Het celgetal van de melk is een indicator voor de aanwezigheid van een intramammaire infectie bij melkvee. Het doel van deze studie was om van 179 mengmelkstalen de resultaten van de elektronische celgetalbepaling via het Fossomatic™ toestel te vergelijken met deze van twee commerciële California Mastitis Testen (CMT) op basis van verslijming, al d...
Article
The aims of this study were to determine whether non-aureus staphylococci (NAS) are present in rectal feces of healthy dairy cows, and if so, to delineate species to which they belong and to study several phenotypic and genotypic traits as a first step toward determining the potential impact of fecal shedding of NAS on bovine udder health. Fecal sa...
Article
Therapie bij E. coli-mastitis bij melkvee
Article
A longitudinal study was conducted to assess to what extent intramammary infection (IMI) with non-aureus staphylococci (NAS) within the first 4 d after calving in dairy heifers affects quarter milk yield (qMY) and quarter milk somatic cell count (qSCC) during the first 4 mo of lactation. In total, 324 quarters from 82 Holstein Friesian heifers from...
Article
Full-text available
The main objective of this study was to evaluate evolutions in herd-level antimicrobial consumption (AMC) and in udder health and milk quality parameters between herds that received mastitis management input on a regular basis (actively advised by the first author; referred to as intervention herds) and herds that did not (referred to as control he...
Article
Full-text available
The objectives of this study were (1) to determine the test characteristics and predictive values of cow-level milk somatic cell count (SCC) information from (multiple) test-day recordings before drying off to identify major-pathogen-infected cows at drying off; and (2) to explore to what extent (an estimate of) the herd prevalence of subclinical m...
Article
In dairy cattle, the milk somatic cell count is the most widely accepted indicator for the presence of intramammary infections. The aim of this study was to compare the results of the electronic cell counting on 179 composite milk samples with the results of two commercially available California Mastitis Tests (CMT), based on either the thickening...
Article
In this study, we studied infection dynamics across the dry period using test-day somatic cell count (SCC) data from 739 Holstein cows from 33 randomly selected commercial dairy herds in Flanders, all of which applied blanket dry-cow therapy at dry-off. First, we determined infection dynamics, combining the last test-day SCC before dry-off and the...
Article
Mastitis affects a high proportion of dairy cows throughout the world and is one of the greater problems faced by the dairy industry today. The disease is still a major cause of economic loss on a dairy farm. Mastitis poses not only negative consequences for the dairy farmer but also for the dairy industry as a number of issues threaten the reputat...
Article
Full-text available
Escherichia coli is a major udder pathogen causing clinical mastitis in dairy cattle and its heat stable endotoxin in powdered infant formula milk is a potential risk factor in neonatal infections. Cephalosporins are frequently used for treatment of mastitis caused by mastitis; however, use of these antimicrobials may induce antimicrobial resistanc...
Article
Oprichting van een diergeneeskundige rechtspersoon (DRP)
Article
Full-text available
Mastitis is a complex, multifactorial disease. Pathogens, cows and farmers (via management) all play a role. It is costly and annoying for the farmer and threatens the image of the entire dairy industry. Prevention and control of mastitis is based on multiple principles that have been known for a long time. To implement them successfully, they shou...
Article
Recently, infectious HEV particles were discovered in milk and fecal samples of dairy cows in China. Given the recent increase of autochthonous HEV infections in Europe, we wanted to assess whether cows constitute an HEV reservoir in this region and hence may be responsible for the advance of HEV through consumption of cow produce. To verify the zo...
Article
Full-text available
The main objectives of this study were to quantify the consumption of antimicrobials on a convenience sample of dairy herds and to determine the association between herd-level antimicrobial consumption and inhibition zone diameters (IZD) of non-aureus staphylococci and Staphylococcus aureus isolates from subclinical mastitis cases. Also, the associ...
Article
Bovine mastitis is among the most prevalent and costly diseases of dairy animals and is caused by a variety of bacterial pathogens including Streptococcus dysgalactiae. However, comprehensive studies reporting the prevalence and antimicrobial resistance profiles of S. dysgalactiae isolated from bovine mastitis are scarce. Therefore, this study was...
Article
Mastitis bij zoogkoeien Trichomonas: een oorzaak van interfertiliteit bij de kat?
Article
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Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named 'bovine neonatal pancytopenia' (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in fou...
Article
Full-text available
Non-aureus staphylococci (NAS), the microorganisms most frequently isolated from bovine milk worldwide , are a heterogeneous group of numerous species. To establish their importance as a group, the distribution of individual species needs to be determined. In the present study, NAS intramammary infection (IMI) was defined as a milk sample containin...
Article
Full-text available
Coagulase-negative staphylococci (CNS) are a common cause of subclinical mastitis in dairy cattle. The CNS inhabit various ecological habitats, ranging between the environment and the host. In order to obtain a better insight into the host response, an experimental infection was carried out in eight healthy heifers in mid-lactation with three diffe...
Article
This study evaluated matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF MS) for the identification of bovine-associated coagulase-negative staphylococci (CNS), a heterogeneous group of different species. Additionally, we aimed to expand the MALDI-ToF MS database with new reference spectra as required to fill the...
Article
Coagulase-negative staphylococci (CNS) have become the main pathogens causing bovine mastitis in recent years. A huge variation in species distribution among herds has been observed in several studies, emphasizing the need to identify subgroup- and species-specific herd-level factors to improve our understanding of the differences in ecological and...
Article
An experimental trial was conducted to explore the effect of vaccination with a polyvalent vaccine against mastitis (Startvac) on the early immune response after experimental intramammary challenge with a heterologous killed Staphylococcus aureus strain. The effect of vaccination on milk production, clinical signs, quarter milk somatic cell count,...
Article
Waar blijven de afgestudeerde dierenartsen na hun studie?
Article
The objectives of this study were (1) to evaluate the test characteristics and predictive values of quarter-composite milk somatic cell count (quarter-cSCC) values based on either a single observation or the geometric mean of multiple recordings as a predictor of intramammary infection (IMI) in lactating dairy cows; and (2) to explore to what exten...
Article
The objective of this study was to assess the in vitro antimicrobial susceptibility of 73 isolates of Mycoplasma bovis isolated from milk of dairy cattle herds of Belgium, Germany, and Italy. Minimal inhibitory concentration (MIC) values were determined by the microbroth dilution method for the following antimicrobials: erythromycin, spiramycin, ti...
Article
Coagulase-negative staphylococci (CNS) are the main cause of bovine intramammary infections (IMI) in many countries. Despite a high prevalence of CNS IMI at parturition, species-specific risk factor studies, relying on accurate identification methods, are lacking. Therefore, this observational study aimed at determining the prevalence and distribut...
Article
The main objectives of this study were to evaluate to what extent variations in herd-level antimicrobial consumption (AMC) can be explained by differences in management practices that are consistently effective in the prevention of (sub)clinical mastitis, on the one hand, and by differences in mastitis treatment strategies, on the other hand. Antim...
Article
Despite the increasing knowledge of prevention and control strategies, bovine mastitis remains one of the most challenging diseases in the dairy industry. This study investigated the antimicrobial activity of 13 species of lactic acid bacteria (LAB), previously isolated from the honey crop of the honeybee, on several mastitis pathogens. The viable...
Article
Bacteria adherence seems to be an essential first stage for the internalization of bacteria into the cytoplasm of the host cell, which is considered an important virulence strategy enabling bacteria to occupy a microenvironment separated from host defense mechanisms. Thus, this study aimed to explore the difference in the capacity of 4 bovine-assoc...
Article
Full-text available
The main objective of this study was to quantify the (compound-specific) antimicrobial consumption (AMC) in adult cattle in a convenience sample of Flemish dairy herds. Antimicrobial consumption data were obtained between 2012 and 2013 by “garbage can audits” and expressed as antimicrobial treatment incidence (ATI), with the unit of the ATI being t...
Article
Coagulase-negative staphylococci (CNS) are the main cause of bovine intramammary infections and are also abundantly present in extramammary habitats such as teat apices. Teat apex colonization (TAC) with CNS has already been explored in lactating dairy cows at the species level, whereas this is not true for dry cows and end-term heifers. Therefore,...
Article
Coagulase-negative staphylococci (CNS) are a major cause of intramammary infections (IMI) in dairy cows and they colonize the teat skin. Staphylococcus haemolyticus, one of the more common CNS, has been identified as a highly versatile opportunistic species. The aim of the present study was to gain better insight into the adaptation of S. haemolyti...
Article
Full-text available
The dry period is acknowledged as playing a key role in mastitis epidemiology and yet surprisingly few studies have explored dry period infection dynamics in detail. The aim of this study was to investigate the dynamics of intramammary infection across a cohort of dairy herds in Europe. Five hundred and twenty-two cows were recruited from 12 farms...
Article
Coagulase-negative staphylococci (CNS) are frequently isolated from quarters with subclinical mastitis, teat apices, and the cows' environment. Virulence, ecology, epidemiological behavior, and effect on udder health vary between different CNS species. Staphylococcus chromogenes, Staph. simulans, and Staph. xylosus are frequently present in milk an...
Article
Coagulase-negative staphylococci (CNS) are the most common bacteria involved in subclinical mastitis in dairy cows. Remarkably, CNS-infected dairy heifers produce more milk than uninfected heifers. Because the lactation hormone prolactin (PRL) is also involved in mammary gland immunity, we investigated the milk PRL response and the mammary quarter...
Article
Full-text available
Background Associations between polymorphisms in the bovine CXCR1 gene, encoding the chemokine (C-X-C motif) receptor 1 (IL8RA), and neutrophil traits and mastitis have been described. In the present study, blood neutrophils were isolated from 20 early lactating heifers with different CXCR1 genotype at position 735 or 980. The cells were incubated...
Article
A cross-sectional study on clinical mastitis, intramammary infection (IMI) and blind quarters was conducted on 50 smallholder dairy farms in Jimma, Ethiopia. A questionnaire was performed, and quarters of 211 cows were sampled and bacteriologically cultured. Risk factors at the herd, cow, and quarter level for clinical mastitis and (pathogen-specif...
Article
Full-text available
Chemokine (C-X-C motif) receptor 1 (CXCR1 or IL-8RA) plays an important role in the bovine mammary gland immunity. Previous research indicated polymorphism c.980A > G in the CXCR1 gene to influence milk neutrophils and mastitis resistance. In the present study, four c.980AG heifers and four c.980GG heifers were experimentally infected with Staphylo...
Article
Full-text available
Previous observational studies suggest an association between polymorphism c.980A>G in the CXCR1 gene, encoding the chemokine (C-X-C motif) receptor 1, and the innate immunity and infection status of the mammary gland. Mammary glands of eight Holstein heifers were experimentally infected with a Staphylococcus chromogenes isolate originating from a...
Article
Since phenotypic methods to identify coagulase negative staphylococci (CNS) from the milk of ruminants often yield unreliable results, methods for molecular identification based on gene sequencing or fingerprinting techniques have been developed. In addition to culture-based detection of isolates, culture-independent methods may be of interest. On...