Science Page: Salmonella antimicrobial resistance and emergence of a new serotype S.4,[5],12:i:-

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

Monitoring antimicrobial resistance is a research topic of utmost importance in the swine industry. Dr. Julio Alvarez at the University of Minnesota is leading some of this effort and this week, his team is presenting the latest results regarding Salmonella antimicrobial resistance in the strains isolated by the University of Minnesota – Veterinary Diagnostic Laboratory between the years 2006 and 2015 and the emergence of a new serotype S.4,[5],12:i:-

Key Points

  • Swine is the reservoir most commonly associated with the S.4,[5],12:i: serotype.
  • The prevalence of S. agona and S. 4,[5],12:i:- in isolates of swine origin recovered from clinical samples received at the Minnesota Veterinary Diagnostic Laboratory (MVDL) in 2006-2015 has increased.
  • In these serotypes an increased proportion of isolates were resistant to ceftiofur and enrofloxacin, compared with other serotypes.
  • The increase in the frequency of isolation of the S.4,[5],12:i:- serotype in humans may be paralleled by a similar increase in swine clinical samples received in the MVDL.

The information synthesized in the figure below is the evolution, over the years, of the percentages of Salmonella isolated at the UMN – VDL, belonging to each of other the following serotypes: typhimurium, agona, derby, typhymurium var5, and 4,5,12:i:-. The increase in the proportion of S.4,5,12:i:- can be seen starting back in 2011-2012.

Salmonella antibiotic resistance

Click here to read the full report about Salmonella serotypes isolated at the UMN – VDL

Science page: Are patterns of spatiotemporal clustering of PRRSv consistent across years?

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we studied a subset of MSHMP participants located in the Midwest to test if some location/time combinations are more prominent during certain seasons across the years. Data from 358 farms in 10 management systems from 2011 to 2015 was compiled to look for clusters.

The clusters found by the SaTScanTM software are represented below. The red circles represent clusters identified in the time period from January to June, whereas blue ones are July to December. We can note that clusters were identified every year but that they varied with time.

Significant PRRS spatial cluster midwest
Significant spatial clusters for PRRSV in the Midwest between 2011 and 2015.

Key points

  • PRRS cases are recognized to be seasonal and aggregated by geographical space.
  • However, spatiotemporal patterns of PRRS clustering were not consistent across years.
  • Drivers of infection spread may vary over the years.

Future uses for this model can be found in the entire report

Science page: Evaluation of biosecurity measures to prevent indirect transmission of PEDV

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

The objective of the study presented today was to evaluate the efficacy of of biosecurity procedures directed at minimizing transmission via personnel following different protocols in controlled experimental settings.

Four (4) groups were housed in different rooms:

  • INF: Pigs infected with PEDV
  • LB: Naive pigs which were exposed to personnel coming from the INF room without changing PPE at all
  • MB: Naive pigs which were exposed to personnel coming from the INF room after washing their hands and face as well as changing footwear and clothing.
  • HB: Naive pigs which were exposed to personnel coming from the INF room after showering as well as changing clothing and footwear.

Results are shown in the figure below. Naive pigs were exposed to personnel from 44h after the pigs in the INF group were infected with PEDV until 10 days post infection.

PEDV indirect transmission biosecurity measures
Viral shedding of pigs. Movements were terminated at 10 dpi. Data presented are average values of viral RNA copies (± SD) of infected (INF), low biosecurity (LB), medium biosecurity (MB) and high biosecurity (HB) groups

Key points:

  • PEDV transmission is likely to occur with contaminated fomites in low biosecurity scenarios.
  • Indirect contact transmission of PEDV can happen very rapidly. Transmission was detected 24h after personnel moved from infected to low biosecurity rooms (no change in clothes, boots or washing hands)
  • Changing PPE (personal protective equipment) and washing skin exposed areas is beneficial to decrease the risk of PEDV transmission.

 

Link to the facilities diagram explaining the experiment setup as well as the results on PEDV indirect transmission in this study.

Science Page: Mycoplasma hyopneumoniae detection in nylon flocked and rayon bud swabs

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

Sterile swabs are used to collect clinical samples from the pig’s respiratory tract. Research studies have shown that the sensitivity of respiratory pathogens detection can vary depending on the type of swab used for sample collection.

The objective of this study was to compare two types of commercial swabs for M. hyopneumoniae detection by real-time PCR.

nylon versus rayon swabs mycoplasma hyopneumoniae 2017.gif
Mycoplasma hyopneumoniae detection by real-time PCR. Results shown are Ct values.

Keypoints:

  • Absorption and detection of M. hyopneumoniae in nylon flocked swabs was significantly higher than rayon bud swabs.
  • Nylon flocked swabs could be suggested to use in chronic infections where the bacterial load could be low.

See the full report for more information on the absorption levels of the two different types of swabs.

Science Page: Antibiotic susceptibility in Pasturella multocida and Streptococcus suis isolated at the Minnesota VDL

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

Antimicrobial resistance has been a preoccupying topic for the past few years. We talked before about what the definition of antibiotic resistance is and how it can be interpreted in two different manners. This week, Dr. Alvarez from the STEMMA lab is reporting the trends in antimicrobial susceptibility observed in strains of Streptococcus suis and Pasteurella multocida isolated at the Minnesota Veterinary Diagnostic Laboratory over the past 10 years. S. suis and P. multocida are common swine pathogens that can cause severe economic losses. Knowing which antibiotics are more likely to be efficient against those bacteria can help in tackling the disease faster.

Key Points:

  • MN-VDL data was analyzed to study antibiotic susceptibility in clinical isolates of Pasteurella multocida and Streptococcus suis from 2006 to 2016.
  • Isolates were highly susceptible to Ampicillin, Ceftiofur, Enrofloxacin and Florfenicol throughout the study period.
  • There were no changes in antibiotic susceptibility against the antibiotics tested routinely across the study period.

The full report can be read here.

Science Page: Are the farms that broke with PED the same?

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

This week, we are proud to introduce a new chart in the Morrison’s Swine Health Monitoring Project. This new addition will be able to answer a common question regarding PEDV outbreaks:

Are the farms currently breaking with PEDV the same than the ones which broke in the past?

To interpret the figure, follows these steps.

  • Horizontal axis represents all the farms that borke with PEDV during the season 2016/2017, with each tick representing an individual farm
  • Vertical axis shows the previous seasons with 2016-2017 on top and 2012-2013 at the very bottom.
  • The color of the cell (year : farm) represents the number of outbreaks experienced; darker blue meaning more outbreaks.

Here is the example of this chart presented this week:

MSHMP PEDV chart
Outbreak history of farms that broke during the 2016-2017 season.

Key points:

The farms that break with PEDV do not appear to have a history of PEDV infections in the prior season.

Of the farms that broke during the 2016/17 season, only 5 (6.5%) of them had outbreaks during the previous season and 43 (56.6%) of them had broken at some point since 2013.

Only one farm has had an outbreak every year since the beginning of the epidemic in the US (season 2013/14).

The full report is available.

Science Page: High levels of dietary zinc under a cloud

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

The addition of zinc in pig’s diet had been a common way to fight against enteric issues at weaning without using antimicrobial in some European countries whereas its use was prohibited in others. Earlier this month, the European Union decided to homogenize practices over the continent by banning the use of high levels of zinc in the diet over environmental and antimicrobial resistance concerns. This new legislation will be implemented progressively over 5 years.

Key points from this week edition:

  • High level (2,500 – 3,000ppm) zinc use (HZU) in feed for 1 to 2 weeks post weaning to counter enteric disease is perhaps the most widely adopted alternative to antibiotic use in pig production globally.
  • The European Union just announced a ban on HZU in piglet feed, to be phased in over 5 years
  • Banning of an effective and widely adopted alternative to antibiotics, at least in part due to perceived concerns about coselection of resistant bacteria, adds another layer of complexity to the development and validation of all interventions to replace antibiotics in food animal production.

Read Dr. Peter Davies’ explanation of the reasons behind this ban.