Category Archives: Research

Research – Pathogenesis of the Pseudomonas aeruginosa Biofilm: A Review

MDPI

Pseudomonas aeruginosa is associated with several human infections, mainly related to healthcare services. In the hospital, it is associated with resistance to several antibiotics, which poses a great challenge to therapy. However, one of the biggest challenges in treating P. aeruginosa infections is that related to biofilms. The complex structure of the P. aeruginosa biofilm contributes an additional factor to the pathogenicity of this microorganism, leading to therapeutic failure, in addition to escape from the immune system, and generating chronic infections that are difficult to eradicate. In this review, we address several molecular aspects of the pathogenicity of P. aeruginosa biofilms. View Full-Text

Research – Legionellosis: A novel mechanism by which the bacterium Legionella pneumophila regulates the immune response of its host cells

Science Daily

Legionellosis or Legionnaires’ disease affected more than 1 800 people in France in 2019 and caused 160 deaths. This emerging disease is caused by Legionella pneumophila, an environmental bacterium that thrives in hot water systems. Researchers have discovered a mechanism that allows Legionella pneumophila to target the immune response of the cells it infects by secreting a small regulatory RNA. This mechanism, not described before, facilitates the survival and proliferation of Legionella pneumophila during infection. The work provides precious information on the strategies used by bacteria to manipulate their host cells.

Research – Shiga Toxin-Producing Escherichia coli and Milk Fat Globules

MDPI

Shiga toxin-producing Escherichia coli (STEC) are zoonotic Gram-negative bacteria. While raw milk cheese consumption is healthful, contamination with pathogens such as STEC can occur due to poor hygiene practices at the farm level. STEC infections cause mild to serious symptoms in humans. The raw milk cheese-making process concentrates certain milk macromolecules such as proteins and milk fat globules (MFGs), allowing the intrinsic beneficial and pathogenic microflora to continue to thrive. MFGs are surrounded by a biological membrane, the milk fat globule membrane (MFGM), which has a globally positive health effect, including inhibition of pathogen adhesion. In this review, we provide an update on the adhesion between STEC and raw MFGs and highlight the consequences of this interaction in terms of food safety, pathogen detection, and therapeutic development. View Full-Text

Research – Report finds food testing policies different between countries

Food Safety News

There are various approaches to food sampling in four nations, including the United States, as shown in a report published by the Food Standards Agency (FSA).

Campden BRI reviewed food control systems in Australia, Canada, New Zealand, and the United States.

The study looked at how authorities perform sampling and analysis of food and feed, systems for gathering intelligence, and other information which informs the sampling and testing program.

Findings suggest there is no one-size-fits-all approach as differences in planning and conducting various sampling activities were observed between the four countries.

Differing approaches
The FSA documents list three types of sampling: for official controls; hypotheses or surveillance sampling; and intelligence sampling. But the terminology used in other countries often varied.

Authorities in Canada, New Zealand, and the United States play both regulation setting and enforcement roles. However, Food Standards Australia New Zealand (FSANZ) sets standards and coordinates responses to food safety incidents but does not have enforcement powers.

Sharing the responsibilities between multiple agencies, which happens in the United States and Australia, may lead to differences in the extent of regulatory oversight in different parts of the country or between foods, sometimes even with similar risks, found the study.

Oversight of the entire food chain in Canada and New Zealand is mainly done by a single regulatory agency, which can facilitate the planning of sampling.

Because of resource constraints and the extensive range of products it oversees, the U.S. Food and Drug Administration tends to apply a risk-based prioritization approach when planning sampling and other activities. The FDA has three types of sampling: product sampling, environmental sampling, and emergency response/emerging issues sampling.

Because products under the U.S. Department of Agriculture’s Food Safety Inspection Service (FSIS) jurisdiction are relatively riskier, FSIS-regulated establishments are subject to a more comprehensive oversight, according to the study.

Research – Multidrug resistance of Escherichia coli in fish supply chain: A preliminary investigation

Wiley Online

Abstract

Ninety-five Escherichia coli isolates recovered from different supply points of freshwater fish namely fish pond (W1, n = 16), wholesale fish market (W2, n = 14), retail fish market (R1, n = 29), street fish vending unit (R2, n = 30), and modern fish vending unit (R3, n = 6) were investigated for antimicrobial-resistant profile and prevalence of antibiotic-resistant genes. Overall, multidrug-resistant (MDR) E. coli in the fish supply chain was 21% with higher MDR incidence in the downstream fish supply points. MDR was relatively higher in the tertiary fish supply points viz., retail fish market (45%), street fish vending unit (30%), and modern fish vending unit (15%) compared to the secondary fish supply point, that is, wholesale fish market (5%) and primary fish supply point, that is, fish pond (5%). All the ampicillin-resistant isolates carried ampC gene, whereas only 21% of the β-lactam resistant isolates carried blaCTX-M-gp1. The tetracycline resistance determinant, tetA (89%) was predominant in the tetracycline-resistant isolates compared to tetB and tetD (11%). The trimethoprim resistance gene, dfrA and sulfonamide-resistance gene, Sul1 were detected in 9% of the trimethoprim-resistant isolates and 9% of the sulfonamide-resistant isolates, respectively. Enterobacterial repetitive intergeneric consensus-PCR has delineated the MDR isolates from the different fish supply points into three major clusters but all the MDR isolates from the street fish vending point are grouped into a single cluster. The results indicate an increase in the proportion of MDR E. coli and the occurrence of diverse MDR profiles in the downstream points of the fish supply chain that needs to be addressed to avoid fish-food-borne antimicrobial resistance.

Research – Enhanced antimicrobial activity against Alicyclobacillus acidoterrestris in apple juice by genome shuffling of Lactobacillus acidophilus NX2-6

Wiley Online

Food safety and quality are seriously compromised by the growth of spoilage bacteria in food. Various lactic acid bacteria (LAB) may inhibit the growth of spoilage bacteria in food and animal feed. In our study, the antibacterial activity of Lactobacillus acidophilus NX2-6 was improved by genome shuffling. The starting populations were obtained via 60Coγ-ray, diethyl sulfate mutagenesis, and UV mutagenesis of protoplasts. The optimal conditions for protoplast formation and regeneration were found to be 30 mg/ml of lysozyme at 37°C for 40 min. The protoplasts were inactivated by UV irradiation for 110 s or by heating at 58°C for 30 min. After two rounds of genome shuffling, the inhibitory activity of strain F50 was improved by 5.6-fold compared to the original strain. The shuffled strain has broad-spectrum antibacterial activity and is a promising candidate for bio-preservative. The antibacterial substances produced by L. acidophilus NX2-6 can be applied to the preservation of apple juice. The results showed that the growth of Alicyclobacillus acidoterrestris in apple juice was significantly inhibited by the addition of 0.1% culture supernatant with acidocin NX2-6 at 28°C and 0.2% culture supernatant with acidocin NX2-6 at 45°C for 30 days. The sugar−acid ratio, pH value, clarity, and fruit flavor of apple juice were well maintained during storage. This study showed that genome shuffling was an effective strategy to improve the bacterial inhibitory activity of LAB and that the shuffled LAB and their metabolites are expected to be used as bio-based food protectors for food safety.

Research – Emergence of non-choleragenic Vibrio infections in Australia

1 Health

Vibrio_vulnificus_01a

Vibrio infection was rarely reported in Tasmania prior to 2016, when a multistate outbreak of Vibrio parahaemolyticus associated with Tasmanian oysters was identified and 11 people reported ill. Since then, sporadic foodborne cases have been identified following consumption of commercially- and recreationally-harvested oysters. The increases in both foodborne and non-foodborne Vibrio infec-tions in Tasmania are likely associated with increased sea water temperatures. As oyster production increases and climate change raises the sea surface temperature of our coastline, Tasmania expects to see more vibriosis cases. Vibriosis due to oyster consumption has been reported in other Australian states, but the variability in notification requirements between jurisdictions makes case and outbreak detection difficult and potentially hampers any public health response to prevent further illness.

USA – Video – How CDC Investigates Foodborne Outbreaks

You Tube

Have you ever wondered how CDC investigates foodborne outbreaks such as Salmonella? PulseNet USA is a nationwide network used to identify the bacteria making people sick and track it back to the source. In this video you will learn how the general public and CDC scientists can work together to identify foodborne illnesses. This video can also be viewed at https://www.cdc.gov/wcms/video/low-re…

Research – Introduction to the Special Issue: Microbiological Safety and Quality of Foods

MDPI

Recent shifts in food production, processing and distribution, linked to the globalization of the food trade and the need to meet new consumers habits, are continuously challenging global food systems. Every effort is being made to ensure healthy and safe, food that is crucial to guarantee public health and wellbeing.
Despite the advancements in food safety management, foodborne diseases (FBD) still remain an important problem worldwide, with a significant negative impact on human health and countries’ economies and development. It has been determined that food unsafe for consumption causes 600 million cases of FBD every year, and 25% of all foods produced globally are lost due to microbial spoilage. Serious outbreaks have occurred, involving both developing and industrialized countries, showing how food safety is a transnational challenge and that a strong joint commitment between food safety authorities is needed.
Despite this awareness, the full extent of the impact of food contamination is still unknown. Foodborne contaminants are numerous, including viruses and bacteria, parasites, chemicals, toxins and allergens that cause a wide range of conditions. Globally, FBD caused by bacteria are more common than those caused by viruses and parasites. [1]. Moreover, between one-third and one-half of all human infectious diseases have a zoonotic origin. Among bacteria, Campylobacter, followed by Salmonella, are the major etiological agents of FBD, while, among viruses, norovirus is the foremost enteric pathogen of foodborne disease worldwide [2].
The most common foodborne parasites instead are protozoa such as Cryptosporidium spp., Giardia intestinalis and Toxoplasma gondii; roundworms such as Trichinella spp. and Anisakis spp.; and tapeworms such as Diphyllobothrium spp. and Taenia spp. [3]. In particular, Anisakiasis is an emerging zoonosis caused by the fish parasitic nematode Anisakis. Humans are accidental hosts that become infected by eating raw or undercooked fish that contain viable Anisakis spp. larvae.
The major determinants for the incidence of FBD are unsafe raw food, abused temperature, inadequate storage, improper handling, undercooking and cross contamination [4]. Food from animal sources, fresh produce and ready-to-eat (RTE) foods are the most at risk. In particular, RTE foods are an emerging issue concerning food safety. Furthermore, they have been demonstrated to contain antimicrobial-resistant strains. Since these products are consumed without any further treatment, they could serve as a vector for the spread of antibiotic-resistant microorganisms, posing a significant threat to public health [5].
The importance of these topics is documented by the increasing number of papers published related to Food Safety. In a basic search using PubMed database, from 1945 to 2021, selecting as the search topic “Microbiological food safety”, a total of 54,210 results were obtained.
Although the first articles concerning microbiological food safety date from 1946, and since then a dozen articles appear in the following years, it is not until 1965 that a significant number of articles are published every year. Figure 1 shows the evolution of the number of papers per year (from 1965 to 2021) published regarding Microbiological food safety. As can be seen in this figure, approximately 80% of these papers have been published in the last 20 years, and the number continues to rise, revealing an increasing and ever-present interest towards the topic addressed in this Special Issue.
Foods 11 00673 g001 550

Research – Ireland – Overview of 2019 Zoonois Data

Zoonoses are diseases and infections naturally transmissible between animals and humans. Transmission may occur via direct contact with an animal or indirect contact with animal excreta (e.g. faeces) present in contaminated food, water or the environment.
Foodborne zoonotic diseases are caused by consuming food or drinking water contaminated by zoonotic pathogenic (disease-causing) microorganisms such as bacteria and their toxins, viruses and parasites. They enter the body through the gastrointestinal tract where the first symptoms often occur. Many of these microorganisms are commonly found in the intestines of healthy food-producing animals.
The risks of contamination are present from farm to fork and require prevention and control throughout the food chain. While it is possible for anybody to become infected with a zoonotic pathogen, certain population groups such as the very young, the elderly and immunocompromised are particularly vulnerable and at greater risk of more serious consequences. The eradication of zoonoses in humans and animals is very challenging.
The impact of zoonoses on the health of humans and animals can however be limited, by (i) monitoring the reservoirs of infectious zoonotic pathogens with a view to understanding and controlling their modes of transfer; (ii) by businesses controlling the hazard along the food chain and; (iii) by educating the public about how to avoid or limit the risk of infection.
The Irish zoonoses report is published annually by the FSAI, in collaboration with the Department of Agriculture, Food and the Marine (DAFM), the Health Service Executive(HSE),the Local Authority Veterinary Service (LAVS), the Sea-Fisheries Protection Authority(SFPA) and the Health Protection Surveillance Centre (HPSC).
The report brings together the results of thousands of tests carried out on samples of food and feed, as well as tests on material of animal or human origin, in an effort to determine the pattern and extent of infection by zoonotic pathogens transmitted to humans from animals. Zoonoses data collected by EU Member States serve as a basis for the EU to set targets for the reduction of these microorganisms in food-producing animals and foodstuffs.
The impact of the reduction programmes on the actual prevalence of zoonoses in animals and foods and related human health cases are then monitored and analysed in the annual EU summary reports published by the European Food Safety Authority and the European Centre for Disease Control and Prevention (EFSA and ECDC, 2020).
The data in the 2019 tables for the results of Irish testing carried out in food, animal and animal feed samples are presented in four categories (routine, census, objective and suspect sampling) depending on the sampling context. Routine sampling is planned sampling but does not involve statistically random sampling. Census sampling is when the totality of a population, on which the data are reported, is controlled.
Objective sampling is the planned selection of a random sample, which is statistically representative of the population to be analysed (EFSA, 2020). Suspect sampling is the unplanned selection of a sample whereby the individual units are selected based on the recent judgement and experience regarding the population, lot or sampling frame, e.g., earlier positive samples (EFSA, 2020).
The samples obtained from suspect sampling may have a higher likelihood of having pathogens present.