Category Archives: Research

Research -Human gut microbes could make processed foods healthier A specific microbe can break down a chemical common in manufactured foods

Science Daily

A new study from Washington University School of Medicine in St. Louis sheds light on how human gut microbes break down processed foods — especially potentially harmful chemical changes often produced during modern food manufacturing processes.

Eating processed foods such as breads, cereals and sodas is associated with negative health effects, including insulin resistance and obesity.

Reporting Oct. 9 in the journal Cell Host & Microbe, scientists have identified a specific human gut bacterial strain that breaks down the chemical fructoselysine, and turns it into harmless byproducts. Fructoselysine is in a class of chemicals called Maillard Reaction Products, which are formed during food processing. Some of these chemicals have been linked to harmful health effects. These findings raise the prospect that it may be possible to use such knowledge of the gut microbiome to help develop healthier, more nutritious processed foods.

USA – CDC report highlights Norovirus, Salmonella and restaurants as key

New Food Magazine

The Centers for Disease Control and Prevention’s (CDC) annual Foodborne Disease Outbreak Report, published in September 2019, has provided data on the 841 foodborne disease outbreaks that occurred throughout the US in 2017, resulting in 14,481 illnesses, 827 hospitalisations, 20 deaths, and 14 food recalls. The statistics provided some eye-opening information, particularly with regards to Salmonella, the Norovirus, and restaurants.

Although Listeria was a key focus of the US Food and Drug Administration (FDA) “swabathons” in 2017, and there was a major E. coli leafy greens outbreak, the two most frequently reported confirmed causes of outbreaks and associated illnesses that year were actually Norovirus and Salmonella.

Norovirus was the cause of:

  • 140 outbreaks, 35 percent of confirmed single-pathogen outbreaks
  • 4,092 illnesses, 46 percent of confirmed single-pathogen illnesses
  • 40 hospitalisations, six percent of confirmed single-pathogen, outbreak-related hospitalisations
  • Four deaths, 20 percent of outbreak-related deaths.

Salmonella was the cause of:

  • 113 outbreaks, 29 percent of confirmed single-pathogen outbreaks
  • 3,007 illnesses, 34 percent of confirmed single-pathogen illnesses
  • 472 hospitalisations, 66 percent of confirmed single-pathogen, outbreak-related hospitalisations
  • Eight deaths, 40 percent of outbreak-related deaths.

Research – Anti‐listeria activity and shelf life extension effects of Lactobacillus along with garlic extract in ground beef

Wiley Online

The current study investigates the effect of Lactobacillus reuteri and Lactobacillus plantarum combined with water extract of garlic on microbial growth, chemical changes, and sensory attributes in ground beef samples at refrigeration condition (+4°C) up to 12 days of storage. in vitro study revealed that garlic extract combined with L. reuteri or L. plantarum caused 2.13 and 2.57 log reduction in the Listeria monocytogenes count, respectively. Combination of L. plantarum and 1% garlic extract significantly (p < .05) reduced aerobic mesophilic bacteria (1.64 log cycle) and L. monocytogenes (1.44 log cycle) counts in ground beef. Lipid oxidation was also significantly (p < .05) lower in samples treated with L. plantarum plus garlic extract (1%). Furthermore, higher sensory scores were received by samples treated with Lactobacillus plus garlic extract. In conclusion, the combination of L. plantarum and garlic extract was found to be suitable to use in ground beef by controlling the L. monocytogenes growth and increasing its shelf life.

Practical Applications

Garlic extract not only has an antimicrobial activity but also has a stimulatory effect on the Lactobacillus spp. growth. On the other hand, some Lactobacillus strains can inhibit pathogenic bacteria. Then, the combination of Lactobacillus and garlic extract may be used to produce new bio‐preserved and functional meat products. The current study indicated the potential of Lactobacillus combined with garlic extract to control microbial and chemical changes in ground beef. The combination of Lactobacillus plantarum and garlic extract significantly (p < .05) reduced Listeria monocytogenes counts and lipid oxidation rates and improved the sensory scores in ground beef.

Research – The effect of sucrose-induced osmotic stress on the sensitivity of Escherichia coli to bacteriocins

NRC Research Press

ABSTRACT

Bacteriocins are antimicrobial peptides, produced by Gram-positive bacteria such as lactococci and staphylococci, that have limited bactericidal action against Gram-negative bacteria. The aim of this paper was to study the sensitivity of three strains of Escherichia coli to bacteriocins: nisin (as Nisaplin®) and two staphylococcal peptides (warnerin and hominin) during sucrose-induced osmotic stress. We found that all peptides in a 0.3 g·mL−1 sucrose solution significantly reduced the number of viable E. coli. The most pronounced antibacterial effect was achieved by nisin against E. coli K-12 (3 log reduction). Slightly less bactericidal effects were observed with warnerin (1 mg·mL−1) and hominin (1 mg·mL−1) in sucrose solution. The lytic activity of staphylococcal peptides was detected by decreased optical density and viable cell counts. Moreover, it was confirmed by the increased amount of DNA and protein in the medium and the morphological changes detected by atomic force microscopy after 20 h of treatment. Zymographic analysis revealed the release of lytic enzymes from E. coli cells after treatment with staphylococcal peptides and sucrose. These results indicated that the antimicrobial action of peptides can be extended to Gram-negative bacteria via combination with high concentrations of sucrose.

Research – Weak spot in pathogenic bacteria

Science Daily mrsa

Antibiotics are still the most important weapon for combatting bacterial infections. But medical science is running out of “ammunition” because of more and more frequently occurring resistances. Scientists from the Technical University of Munich and the Max Planck Institute of Molecular Physiology has now elucidated the structure of the proteolytic complex ClpX-ClpP. This is a key to development of innovative antibiotics which target the degradation process of defective proteins in bacteria.

Almost 700,000 people in Europe suffer from infections every year through antibiotic-resistant pathogens; approximately 33,000 of them die. Despite this enormous and globally increasing danger, very few new antibiotics have been developed and approved in the past few decades.

There is no improvement in sight. That is why it is urgently necessary to find new points of attack in pathogenic bacteria and to develop new antibiotics which exploit these weak spots.

New mechanism of action destroys bacteria

A particularly promising point of attack for antibacterial therapies is the proteolytic enzyme ClpP: on the one hand it plays an important role in bacterial metabolism, and on the other hand it ensures the controlled degradation of defective proteins.

But for this purpose it requires the ClpX protein as a starting aid. In the complex with ClpP, ClpX identifies proteins which should be degraded, unfurls them and guides them into its barrel-like degradation chamber.

Scientists in the groups led by Prof. Stephan Sieber, Technical University of Munich (TUM) and Prof. Stefan Raunser, Director at the Max Planck Institute of Molecular Physiology in Dortmund, have now elucidated the three-dimensional structure of the ClpX-ClpP proteolytic complex for the first time and thereby established an important basis for future pharmacological strategies.

A new class of potential antibiotics — the so-called acyldepsipeptide (ADEP) antibiotics — also brings about an uncontrolled degradation through ClpP without the support of ClpX. As a result also vital proteins are destroyed — with lethal consequences for the bacteria.

This unique mechanism of action has considerable innovation potential in the fight against pathogenic bacteria. Whereas common antibiotics act through the inhibition of vital processes, in this case the antibacterial effect is achieved through the activation of a process.

Research – EU – Cryptosporidiosis – Annual Epidemiological Report for 2017

ECDC crypto

Executive summary

Key facts

  • For 2017, 21 EU/EEA countries reported 11 449 cryptosporidiosis cases, of which 11 418 were confirmed.
  • The notification rate was 3.2 confirmed cases per 100 000 population.
  • Germany, the Netherlands and the United Kingdom (UK) accounted for 71% of all confirmed cases, with the United Kingdom alone accounting for 44%.
  • Most of the cases were reported in September 2017, following the seasonal pattern of previous years.
  • Children aged 0–4 years had the highest notification rate of 12.5 cases per 100 000 population.

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Research -Highly virulent listeriosis pathogen discovered

Science Daily

The bacterium Listeria monocytogenes can cause listeriosis, a life-threatening infection in animals and humans. Contaminated food is a frequent source of infection. Elderly people, people with a weakened immune system and pregnant women are particularly at risk with a mortality rate of up to 30 per cent. An international research group led by the Institute of Medical Microbiology at the Justus Liebig University Giessen (JLU) has now discovered the most virulent representatives of this bacterial species to date. They were identified as the cause of serious diseases in sheep in a remote area of the Chinese province Jiangsu.

‘The detection of a completely new form of pathogenic Listeria monocytogenes in China highlights the need for international collaboration’, emphasises Prof. Dr Trinad Chakraborty, Director of the Institute of Medical Microbiology at the JLU and research scientist at the German Center for Infection Research (DZIF). ‘Only by combining resources and expertise can we rapidly identify newly emerging threats to food safety from highly virulent strains worldwide.’

After decoding the genome sequence of these bacteria, the scientists were able to determine the genetic basis for their hypervirulence. They identified the factors that enhance the ability of this Listeria strain to cause severe septic diseases. ‘These isolates are unique in the sense that they combine the virulence characteristics of various highly pathogenic Listeria species that infect animals or humans into a single strain’, says Prof. Chakraborty. ‘Since listeriosis is a food-borne infection, measures to identify such highly virulent strains are extremely urgent.’

Clinical symptoms of listeriosis include fever, blood poisoning (sepsis) and infections of the central nervous system, which can lead to lifelong sequelae. Infections during pregnancy can lead to premature birth, miscarriage or stillbirth. Both raw and processed foods can be contaminated by listeria, especially dairy products, meat, seafood and ready-to-eat products such as pre-packaged salads. Due to the extremely hazardous nature of listeriosis in humans, many countries have set up monitoring systems to quickly identify and recall contaminated food products. Since it can take up to 70 days for a listeria infection to manifest itself with severe symptoms, it can be very difficult to identify the source of contamination and initiate the food recall.

Currently, there are reported listeriosis outbreaks in Germany (Hesse), the Netherlands, Lithuania, Spain, Great Britain, Canada and the United States, posing a particular threat to vulnerable populations. Therefore, considerable efforts are now underway to identify the origin of these pathogens and prevent further outbreaks of listeriosis.


Story Source:

Materials provided by German Center for Infection ResearchNote: Content may be edited for style and length.


Journal Reference:

  1. Yuelan Yin, Hao Yao, Swapnil Doijad, Suwei Kong, Yang Shen, Xuexue Cai, Weijun Tan, Yuting Wang, Youwei Feng, Zhiting Ling, Guoliang Wang, Yachen Hu, Kai Lian, Xinyu Sun, Yuliang Liu, Chuanbin Wang, Kuhua Jiao, Guoping Liu, Ruilong Song, Xiang Chen, Zhiming Pan, Martin J. Loessner, Trinad Chakraborty, Xin’an Jiao. A hybrid sub-lineage of Listeria monocytogenes comprising hypervirulent isolatesNature Communications, 2019; 10 (1) DOI: 10.1038/s41467-019-12072-1