Research – How bacteria beat immune systems

Science Daily

The evolution of more severe infections is not necessarily driven by bacteria multiplying faster, new research shows.

Humans and animals can develop resistance to harmful bacteria (pathogens) over time or with antibiotics or vaccines, and it is usually assumed that pathogens respond by multiplying faster.

But the new study — led by the University of Exeter — shows pathogen virulence and replication rates can evolve separately.

The authors believe that, once resistance spreads in host species, virulence may be driven by other means such as by manipulating host immune systems.

The research examined the spread of bacteria called Mycoplasma gallisepticum among house finches — a rare example of a well-studied host-bacteria evolution where humans have not intervened with antibiotics or vaccines.

“We actually have a very poor understanding of how pathogens evolve in response to natural host resistance,” said Dr Camille Bonneaud, of the Centre of Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“This is because there are very few systems in the wild that have been monitored in sufficient detail, without being subjected to human intervention.

“We typically assume that pathogens respond to host resistance (including to vaccines) by increasing their rate of replication, allowing them to transmit faster to other hosts before they are cleared by their current host.

“However, our study shows that pathogens can evolve to become more virulent without increasing their rate of replication.

“We hypothesise that the increase in virulence that we observed in this study was driven by an improved ability of the pathogen to manipulate the host immune system in order to generate the symptoms necessary for its transmission.”

The authors say this could lead to new approaches for tackling pathogens.

For example, if trying to kill the pathogen inevitably leads to more virulent infections, it might be worth trying to slow down pathogen evolution by combining treatments that both eliminate the pathogen and prevent it manipulating host immune systems.

Some populations of house finches have been exposed to Mycoplasma gallisepticum for more than 20 years, while others have not — and have therefore not developed resistance.

In the study, carried out in Arizona and supported by Arizona State University and Auburn University, 57 finches from previously unexposed populations were exposed to the pathogen.

The findings show virulence has increased consistently over more than 150,000 bacterial generations since outbreak (1994 to 2015).

By contrast, while replication rates increased from outbreak to the initial spread of resistance (1994 to 2004), no further increases have occurred subsequently (2007 to 2015).

Research –

Canadian Journal of Microbiology

 

ABSTRACT

Probiotics have become one of the potential solutions to global restriction on antibiotic use in food animal production. Bacillus species have been attractive probiotics partially due to their long-term stability during storage. In this study, 200 endospore-forming bacteria isolates were recovered from sourdough and the gastrointestinal tract (GIT) of young broiler chicks. Based on the production of a series of exoenzymes and survivability under stress conditions similar to those in the poultry GIT, 42 isolates were selected and identified by 16S rRNA gene sequencing. Seven strains with a profile of high enzymatic activities were further evaluated for sporulation efficiency, biofilm formation, compatibility among themselves (Bacillus spp.), and antagonistic effects against three bacteria pathogenic to poultry and humans: Enterococcus cecorumSalmonella enterica, and Shiga-toxin-producing Escherichia coli. The strains from sourdough were identified as Bacillus amyloliquefaciens whereas the ones from the chicks’ GIT were Bacillus subtilis. These strains demonstrated remarkable potential as probiotics for poultry.

RASFF Alerts – Salmonella – Chicken Breast Fillet – Chilled Chicken Fillet

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RASFF – Salmonella enterica ser. Enteritidis (presence /25g) in chicken breast fillet from Poland in Poland

RASFF – Salmonella (presence /25g) in chilled chicken fillet preparations from Belgium in Belgium

RASFF Alert – Aflatoxin – Pistachios in Shell

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RASFF – aflatoxins (B1 = 45; Tot. = 49.2 µg/kg – ppb) in pistachios in shell from Iran in Germany

RASFF Alert – Foodborne Outbreak – Listeria monocyotgenes – Carne Mechada

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RASFF – foodborne outbreak caused by Listeria monocytogenes (>1.5x10E4 CFU/g) in chilled roast pork (carne mechada) from Spain in Spain

Spain -Listeria, the stealthy pathogen that kills 70 people a year in Spain

El Pais

The country ranks third in the EU for reported cases of listeriosis, which is caused by a common bacteria that withstands freezing temperatures and oxygen starvation

On a European scale, Spain had the third highest incidence of reported listeriosis cases in 2016, trailing Germany and France, according to the European Center for Disease Prevention and Control.

The epidemiologist Zaida Herrador from the Carlos III Health Institute is the main author of the biggest research effort to date on the incidence of listeria in Spain. From 1997 to 2015, a total of 5,696 people were admitted to hospital for listeriosis. Almost 1,000 of these cases proved lethal (17%) in a trend that has seen the average figure of 20 annual deaths two decades ago rise to an average of 70 in recent years. “It’s a growing problem, and there is still a lot to be investigated,” says Herrador. “We can see that the number of cases is growing noticeably, but presumably this is because they are being reported more. It wasn’t an illness that had to be declared until 2015.”

USA – Website for reporting Food Illness – iwaspoisoned.com

https://www.iwaspoisoned.com/

iwaspoisoned.com is for people who love to eat out but don’t expect to be ill because of it. The platform is a consumer led website for diners to report suspected food poisoning or bad food experiences. It allows users to report food poisoning from businesses, food products, or if they have general symptoms. This real time information is shared by consumers, food authorities, restaurants, and industry with one aim – to make eating a safer experience. By aggregating and analyzing citizen-submitted data, our site prevents food poisoning outbreaks, reduces risks, and creates better outcomes for restaurants, shareholders, and the public.

 

Mission of iwaspoisoned.com

Use data to bring together consumers, public health, and industry in near real-time to keep people safer and businesses more profitable.

 

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This is especially true of IWasPoisoned, which has collected about 89,000 reports since it opened in 2009. Consumers use the site to decide which restaurants to avoid, and public health departments and food industry groups routinely monitor its submissions, hoping to identify outbreaks before they spread. The site has even begun to tilt stocks, as traders on Wall Street see the value of knowing which national restaurant chain might soon have a food-safety crisis on its hands.