7 research outputs found
Differentiation of Porcine <i>Brachyspira</i> Species by a Novel <i>nox</i> PCR-Based Restriction Fragment Length Polymorphism Analysis
No full textABSTRACT
A novel PCR-based restriction fragment length polymorphism analysis of the
Brachyspira nox
gene was developed. The restriction patterns for
Brachyspira hyodysenteriae
,
B
.
pilosicoli
,
B
.
intermedia
,
B
.
murdochii
, and
B
.
innocens
were highly distinct with two restriction endonucleases only. The assay proved to be user-friendly and robust.
</jats:p
Differences in the Population Structure of Invasive Streptococcus suis Strains Isolated from Pigs and from Humans in the Netherlands
No full textStreptococcus suis serotype 2 is the main cause of zoonotic S. suis infection despite the fact that other serotypes are frequently isolated from diseased pigs. Studies comparing concurrent invasive human and pig isolates from a single geographical location are lacking. We compared the population structures of invasive S. suis strains isolated between 1986 and 2008 from human patients (N = 24) and from pigs with invasive disease (N = 124) in the Netherlands by serotyping and multi locus sequence typing (MLST). Fifty-six percent of pig isolates were of serotype 9 belonging to 15 clonal complexes (CCs) or singleton sequence types (ST). In contrast, all human isolates were of serotype 2 and belonged to two non-overlapping clonal complexes CC1 (58%) and CC20 (42%). The proportion of serotype 2 isolates among S. suis strains isolated from humans was significantly higher than among strains isolated from pigs (24/24 vs. 29/124; P<0.0001). This difference remained significant when only strains within CC1 and CC20 were considered (24/24 vs. 27/37,P = 0.004). The Simpson diversity index of the S. suis population isolated from humans (0.598) was smaller than of the population isolated from pigs (0.765, P = 0.05) indicating that the S. suis population isolated from infected pigs was more diverse than the S. suis population isolated from human patients. S. suis serotype 2 strains of CC20 were all negative in a PCR for detection of genes encoding extracellular protein factor (EF) variants. These data indicate that the polysaccharide capsule is an important correlate of human S. suis infection, irrespective of the ST and EF encoding gene type of S. suis strains
Analyses of Dutch Haemophilus parasuis isolates by serotyping, genotyping by ERIC-PCR and Hsp60 sequences and the presence of the virulence associated trimeric autotransporters marker
No full textDistribution of <i>Streptococcus suis</i> isolates among patients and pigs in the Netherlands, according to serotype and genotype.
No full text<p>Distribution of <i>Streptococcus suis</i> isolates among patients and pigs in the Netherlands, according to serotype and genotype.</p
Phylogenetic analyses of concatenated sequences of seven housekeeping gene fragments of <i>Streptococcus suis</i> strains isolated from human patients and pigs in the Netherlands.
No full text<p>The tree was constructed using Neighbor-Joining algorithm in SplitsTree4 using MLST allelic profiles. Distance matrix was obtained from allelic profiles using the SplitsTree program at <a href="http://pubmlst.org/analysis/" target="_blank">http://pubmlst.org/analysis/</a>. ST’s comprising the different clonal complexes are circled. Serotypes are indicated by coloured dots with a diameter corresponding to the number of strains. The horizontal line indicates the scale for genetic distance in arbitrary units.</p
Combined eBURST analysis of the entire <i>S. suis</i> MLST database (accessed on 2 August 2011) and the complete collection of strains isolated from pigs and humans with invasive <i>S. suis</i> infection described in this study.
No full text<p>Clonal complexes and the predicted founder STs are indicated by blue dots. Secondary founders are indicated by yellow dots. The size of the dots is relative to the number of isolates with the respective ST present in the combined databases. Numbers in magenta correspond to the STs of the Dutch isolates in this study. Clonal complexes relevant to this study are circled and labeled. Isolates cultured from human patients in this study are of CC1 (ST1, ST134 and ST148); and of CC20 (ST20).</p
Livestock-associated methicillin resistant Staphylococcus aureus in pigs - prevalence, risk factors and transmission dynamics
No full text In 2004, an association between human carriage of methicillin resistant Staphylococcus aureus (MRSA) and contact with pigs was found. To assess the implications of this finding for veterinary and public health more insight into the prevalence, risk factors and transmission dynamics of this so-called livestock-associated (LA-)MRSA was needed. Therefore, field and experimental studies were conducted in pig and human populations of which the results are presented in this thesis. First, observational studies on pig farms were performed to estimate the prevalence of MRSA positive herds, and to identify factors associated with LA-MRSA in pig herds. It was shown that LA-MRSA was present in the majority, i.e. ~70%, of Dutch pig herds and that the prevalence increased over time. Larger herds were more often found LA-MRSA positive than smaller herds, and transmission was shown to occur by animal trade. From all this, it was concluded that LA-MRSA has become endemic in the Dutch pig population. Secondly, studies on LA-MRSA in pigs, the environment and personnel in pig slaughterhouses were performed. In pigs, a clear increase in LA-MRSA positive pigs from 0 to 60% was shown in the time period between loading at the farm and stunning at the slaughterhouse. This indicated a very rapid transmission of LA-MRSA between pigs through direct contact or through contact with a contaminated environment. An increase in LA-MRSA positive environmental samples taken in the slaughterhouse was found during the working day. In personnel, LA-MRSA prevalence was 6% and working with live pigs was the single most important factor for being positive; personnel not working with pigs or working only with dead pigs were all LA-MRSA negative. Thirdly, transmission of LA-MRSA within herds was studied longitudinally both in an experimental setting and also in 6 pig herds. Transmission rates and the factors affecting these rates were determined. The results of both studies indicated that LA-MRSA is able to spread easily and persist in pig populations, resulting in an endemic situation. Use of selective antimicrobials has a positive effect on the transmission rate of LA-MRSA, but transmission occurs even without use of antimicrobials. The key to limiting LA-MRSA transmission from pigs to humans is to eliminate the source, i.e. eradicate LA-MRSA from pig herds, and a combination of different intervention strategies controlling both within- and between-herd transmission will be needed to achieve this. </p
