Category Archives: Pathogen

Research – Differences Among Incidence Rates of Invasive Listeriosis in the U.S. FoodNet Population by Age, Sex, Race/Ethnicity, and Pregnancy Status, 2008–2016

Posted on February 14, 2019 by | Leave a comment

Mary Ann Leibert listeria

Listeria monocytogenes is a foodborne pathogen that disproportionally affects pregnant females, older adults, and immunocompromised individuals. Using U.S. Foodborne Diseases Active Surveillance Network (FoodNet) surveillance data, we examined listeriosis incidence rates and rate ratios (RRs) by age, sex, race/ethnicity, and pregnancy status across three periods from 2008 to 2016, as recent incidence trends in U.S. subgroups had not been evaluated. The invasive listeriosis annual incidence rate per 100,000 for 2008–2016 was 0.28 cases among the general population (excluding pregnant females), and 3.73 cases among pregnant females. For adults ≥70 years, the annual incidence rate per 100,000 was 1.33 cases. No significant change in estimated listeriosis incidence was found over the 2008–2016 period, except for a small, but significantly lower pregnancy-associated rate in 2011–2013 when compared with 2008–2010. Among the nonpregnancy-associated cases, RRs increased with age from 0.43 (95% confidence interval: 0.25–0.73) for 0- to 14-year olds to 44.9 (33.5–60.0) for ≥85-year olds, compared with 15- to 44-year olds. Males had an incidence of 1.28 (1.12–1.45) times that of females. Compared with non-Hispanic whites, the incidence was 1.57 (1.18–1.20) times higher among non-Hispanic Asians, 1.49 (1.22–1.83) among non-Hispanic blacks, and 1.73 (1.15–2.62) among Hispanics. Among females of childbearing age, non-Hispanic Asian females had 2.72 (1.51–4.89) and Hispanic females 3.13 (2.12–4.89) times higher incidence than non-Hispanic whites. We observed a higher percentage of deaths among older patient groups compared with 15- to 44-year olds. This study is the first characterizing higher RRs for listeriosis in the United States among non-Hispanic blacks and Asians compared with non-Hispanic whites. This information for public health risk managers may spur further research to understand if differences in listeriosis rates relate to differences in consumption patterns of foods with higher contamination levels, food handling practices, comorbidities, immunodeficiencies, health care access, or other factors.

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Posted in food contamination, food death, Food Hygiene, Food Illness, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Uncategorized

Research – PopPUNK advances speed of bacterial pathogen surveillance

Posted on January 29, 2019 by | Leave a comment

Science Daily

In a study published today in Genome Research, researchers developed PopPUNK (Population Partitioning Using Nucleotide K-mers), a computational tool for analyzing tens of thousands of bacterial genomes in a single run, up to 200-fold faster than previous methods. Researchers envision PopPUNK will expedite the identification of bacterial strains as the scale of bacterial genomes being sequenced increases and, importantly, allow public health agencies to quickly identify outbreak strains that pose a public health risk.

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Technology, Food Testing, Pathogen, pathogenic, Uncategorized, Whole Genomic Sequencing

Research – How to kill pathogens on seafood

Posted on December 19, 2018 by | Leave a comment

Food Processing

Controlled release antimicrobial film makes seafood safer.

Seafood may be contaminated with bacterial pathogens, such as Vibrio and Salmonella, which can survive long-term freezing conditions. Vibrio naturally occur in marine environments and Salmonella can contaminate seafood during production or processing and both are concerns for the seafood industry.

However, a solution may be at hand. A biodegradable, edible film made with plant starch and antimicrobial compounds may control the growth of foodborne pathogens on seafood, according to a group of international researchers.

Catherine Cutter, professor of food science, Penn State, explained, “We have the ability to develop a film with antimicrobial activity that can kill foodborne pathogens on food surfaces. Given the recent outbreaks that we have seen with a number of food products, coming up with something that can be used by the industry to kill microorganisms on the surfaces of food is a noble area of research to investigate.

“Vibrio and Salmonella are somewhat susceptible to freezing,” Cutter said. “So, if you treat bacterial cells with antimicrobials and then freeze them, the approach can be more lethal.”

Freezing does not kill bacteria. However, when freezing food, ice crystals can form from the water in food. The ice crystals, Cutter said, can act like “daggers” and pierce the bacterial cell wall, causing damage to the cell.

Researchers used a blend of thermoplastic starch, a biodegradable polymer made from tapioca powder and a gelatin coating containing antimicrobials known as Nisin Z and lauric arginate (LAE).

 

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Posted in Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, microbial contamination, Pathogen, pathogenic, Salmonella, Uncategorized, Vibrio, Vibrio cholera, Vibrio parahaemolyticus, Vibrio vulnificans, water microbiology

Research – Innate antimicrobial immunity in the skin: A protective barrier against bacteria, viruses, and fungi

Posted on December 11, 2018 by | Leave a comment

PLOS One

The epidermis, the outermost layer of the skin, is a physical barrier against pathogens. However, breach of the skin barrier through wounding introduces a myriad of microbes to the site of injury. Upon disturbance of the epidermal barrier, the innate immune system and its effectors play a key role in protecting humans against cutaneous and systemic infection [1]. Major constituents of the innate immune system include phagocytic cells, such as macrophages, neutrophils, and dendritic cells, as well as innate leukocytes, such as natural killer (NK) cells, mast cells, basophils, and eosinophils. In addition, epidermal keratinocytes act as active innate immune cells. In response to sensing pathogen-associated molecular patterns (PAMPs) expressed by microbes and host danger molecules, innate immune receptors present on keratinocytes become activated, causing release of inflammatory cytokines and host antimicrobial molecules [2, 3].

Recognition of pathogens

The first step of any immune response is recognition of potential pathogens. Germline-encoded pattern recognition receptors (PRRs) recognize PAMPs present on microbes and damaged-associated molecular patterns (DAMPs) on host cells (Fig 1) [4]. The four primary groups of human PRRs are toll-like receptors (TLRs), nucleotide-binding oligomerization domain-like receptors (NLRs), retinoic acid-inducible gene 1 (RIG-I)-like helicase receptors (RLRs) and c-type lectin receptors (CLRs) [4]. Signaling through PRRs has long been known to be essential for activation of the innate immune response. For example, stimulation of TLR2 increases the immune response to pathogens and helps rescue the inflammatory response of immunosuppressed patients with sepsis [5]. Although PRRs are not as specific as immune effectors of the adaptive immune system, different PRRs have evolved to recognize different molecular patterns [6]. For example, TLR2, TLR6, and nucleotide-binding oligomerization domain-containing protein 2 (NOD2) appear to play an important role in host defense against staphylococcal aureus, whereas TLRs 2, 3, 7, 8, and 9 have been found to be activated by many viruses, including members of the herpesviruses, papillomaviruses, and poxviruses [7, 8]. CLRs and TLRs 2, 4, and 9 are thought to be primary receptors involved in recognition of fungal pathogens such as Candida albicans, and there are reports of specific PRR deficiencies in patients with chronic mucocutaneous infections [9, 10].

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Posted in Bacteria, Food Virus, Pathogen, pathogenic, Uncategorized, Virus

Research – Advancing Retail Food Policy Debates: Estimating the Risk of Contaminated Servings of Food Attributed to Employee Food Handling Practices in Retail Food Establishments

Posted on December 10, 2018 by | Leave a comment

Journal of Food Protection

Food employee contamination of ready-to-eat foods through improper food handling practices is an important contributing factor for foodborne illness in retail and food service establishments. Decreasing the incidence of improper food handling practices is a frequent topic of retail food policy deliberations that often involves estimating the degree to which a proposed policy might affect a specific food handling practice. However, the potential reduction in contaminated servings of food, and therefore foodborne illnesses avoided, associated with a given proposed policy change, is all too often uncertain. This article discusses the components, assumptions, and applications of the food handling practices model, a quantitative model that estimates the impact of food handling practices on servings of food moving along three consecutive stages: the contamination stage, the pathogen control stage, and the foodborne illness stage. To our knowledge, this article is the first time the model has been presented in an academic platform, and we also explore unique and interesting aspects of the model not addressed in publicly available documents. Risk-based estimates for contaminated servings of food attributed to changes in one or multiple food handling practices are derived that provide an important link between increased compliance with proper food handling practices and public health. Model estimates show that decreases in the incidence of inappropriate food handling practices lead to varying levels of contaminated food servings avoided, depending on the food handling practice. The ability to derive such estimates provides stakeholders and the general public with a means of understanding the relative impact of proposals to reduce improper food handling and to help inform regulatory food safety policy discussions and decision making.

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Posted in food contamination, Food Hygiene, Food Inspections, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, microbial contamination, Microbiology, Pathogen, Uncategorized

Research – Migratory birds along the Mediterranean – Black Sea Flyway as carriers of zoonotic pathogens

Posted on November 10, 2018 by | Leave a comment

NRC

At the crossroad between Europe, Asia, and Africa, Bulgaria is part of the Mediterranean – Black Sea Flyway (MBSF) used by millions of migratory birds. In this study, bird species migrating through Bulgaria were investigated as carriers of zoonotic pathogens. In total, 706 birds belonging to 46 species were checked for the presence of various bacterial pathogens (Campylobacter, Yersinia, Salmonella, Listeria, Escherichia coli, Staphylococcus aureus, Francisella tularensis, Coxiella burnetii, Borrelia burgdorferi, and Brucella spp.). From 673 birds we investigated fecal samples, from the remaining 33, blood samples. We detected Campylobacter 16S rDNA gene in 1.3% of birds, but none were of pathogenic Campylobacter jejuni and Campylobacter coli species. Escherichia coli 16S rDNA gene was found in 8.8% of the birds. Out of 34 birds that transported Yersinia enterocolitica strains (5.05%), only 1 carried a pathogenic isolate. Three birds (0.4%) were carriers of nonpathogenic Salmonella strains. Four avian samples (0.6%) were positive for Listeria monocytogenes and 1 (0.15%) was positive for Brucella spp. None of the birds tested carried the tick-borne pathogens C. burnetii or B. burgdorferi sensu lato. Antibiotic-resistant strains were detected, suggesting that migratory birds could be reservoirs and spreaders of bacterial pathogens as well as antibiotic resistance genes.

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Posted in Campylobacter, E.coli, Food Pathogen, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Salmonella, Staphylococcus aureus, Uncategorized, Yersinia

Research – Composting To Inactivate Foodborne Pathogens for Crop Soil Application: A Review

Posted on October 27, 2018 by | Leave a comment

Journal of Food Protection

Compost is organic material that has been degraded into a nutrient-stabilized humus-like substance through intense microbial activity, which can provide essential plant nutrients (nitrogen, phosphorus) to aid in the growth of fruits and vegetables. Compost can be generated from animal waste feedstocks; these can contain human pathogens, which can be inactivated through the heat and microbial competition promoted during the composting process. Outbreaks of infections caused by bacterial pathogens such as Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes on fruit and vegetable commodities consumed raw emphasize the importance of minimizing the risk of pathogenic contamination on produce commodities. This review article investigates factors that affect the reduction and survival of bacterial foodborne pathogens during the composting process. Interactions with indigenous microorganisms, carbon:nitrogen ratios, and temperature changes influence pathogen survival, growth, and persistence in finished compost. Understanding the mechanisms of pathogen survival during the composting process and mechanisms that reduce pathogen populations can minimize the risk of pathogen contamination in the cultivation of fruits and vegetables.

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Posted in E.coli O157, E.coli O157:H7, food contamination, Food Hygiene, Food Micro Blog, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Salmonella, Uncategorized

Research – Ruminant and chicken: important sources of Campylobacteriosis in France

Posted on June 22, 2018 by | Leave a comment

Poultry Med

Campylobacter spp. are regarded as the most common foodborne bacterial zoonosis in Europe, despite potential underestimation due to underreporting of cases. In France, C. jejuni is responsible for nearly 80% of human infections while C. coli accounts for around 15%. The economic burden of campylobacteriosis has been estimated to 2.4 billion euros annually in Europe, with estimates of £50 million in 2008–2009 in the United Kingdom and 82 million euros in the Netherlands in 2011.Pathogen source attribution studies are a useful tool for identifying reservoirs of human infection. Based on Multilocus Sequence Typing (MLST) data, such studies have identified chicken as a major source of C. jejuni human infection. The use of whole genome sequence-based typing methods offers potential to improve the precision of attribution beyond that which is possible from 7 MLST loci. Using published data and 156 novel C. jejuni genomes sequenced in this study, the researchers performed probabilistic host source attribution of clinical C. jejuni isolates from France using three types of genotype data: comparative genomic fingerprints; MLST genes; 15 host segregating genes previously identified by whole genome sequencing. Consistent with previous studies, chicken was an important source of campylobacteriosis in France (31–63% of clinical isolates assigned). There was also evidence that ruminants are a source (22–55% of clinical isolates assigned), suggesting that further investigation of potential transmission routes from ruminants to human would be useful.

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Posted in Campylobacter, food contamination, Food Hygiene, Food Inspections, Food Microbiology, Food Microbiology Blog, Food Pathogen, Food Safety, Food Testing, Pathogen, pathogenic, Research, Uncategorized

Holland – Research on pathogens in dairy goat and dairy sheep farms

Posted on June 18, 2018 by | Leave a comment

RIVM 

Image CDC

Synopsis

Animals can carry pathogens that can cause disease in humans (zoonoses). In 2016, the RIVM and the NVWA investigated whether dairy goats and dairy sheep carry such pathogens; sometimes this is also done for livestock farmers, their family members and employees. These pathogens usually cause diarrhoea but sometimes the infections are more severe.

Research shows that a few pathogens occur often on dairy goat and dairy sheep farms. These bacteria reside in the intestines of the animals, and are excreted in manure. A small amount of manure is enough to contaminate raw milk or unpasteurised cheese. Visitors to these farms can also become infected if they come into contact with the animals or their environment. Contamination can be prevented by consuming or processing all milk pasteurized. Visitors can reduce the risk of disease by washing their hands if they have been in contact with the animals or their environment.

STEC and Campylobacter bacteria, in particular, were frequently found. STEC was detected at virtually all the farms that were investigated. Campylobacter was detected at 33 percent of the goat farms and 95.8 percent of the sheep farms. These bacteria were found much less often among the farmers and their family members. Listeria was detected less often: at 8.8 percent of the goat farms and 16.7 percent of the sheep farms, and not among people. However, it is a relevant pathogen since unpasteurised soft cheese is the most important source of Listeria infection in humans.

Salmonella was not found at dairy goat farms but was found at 12.5 percent of the dairy sheep farms. On most farms, only a type of Salmonella that is not transmitted to humans was found. ESBL-producing bacteria, which are insensitive to many antibiotics, were detected at 1.7 percent of the goat farms and 4.2 percent of the sheep farms. They were also found in 6.8 percent of the people. This percentage is not higher than for the general population.

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Posted in Campylobacter, E.coli, E.coli O103, E.coli O104, E.coli O111, E.coli O121, E.coli O128, E.coli O145, E.coli O157, E.coli O157:H7, E.coli O26, Food Pathogen, Listeria, Listeria monocytogenes, Pathogen, pathogenic, Salmonella, STEC, Uncategorized

Research – Scientists map genetic codes of 3,000 dangerous bacteria

Posted on June 9, 2018 by | Leave a comment

Yahoo News 

 

By Kate Kelland

(Reuters) – Scientists seeking new ways to fight drug-resistant superbugs have mapped the genomes of more than 3,000 bacteria, including samples of a bug taken from Alexander Fleming’s nose and a dysentery-causing strain from a World War One soldier.

The DNA of deadly strains of plague, dysentery and cholera were also decoded in what the researchers said was an effort to better understand some of the world’s most dangerous diseases and develop new ways to fight them.

The samples from Fleming – the British scientist credited with discovering the first antibiotic, penicillin, in 1928 – were among more than 5,500 bugs at Britain’s National Collection of Type Cultures (NCTC) one of the world’s largest collections of clinically relevant bacteria.

The first bacteria to be deposited in the NCTC was a strain of dysentery-causing Shigella flexneri that was isolated in 1915 from a soldier in the trenches of World War One.

“Knowing very accurately what bacteria looked like before and during the introduction of antibiotics and vaccines, and comparing them to current strains, … shows us how they have responded to these treatments,” said Julian Parkhill of Britain’s Wellcome Sanger Institute who co-led the research.

“This in turn helps us develop new antibiotics and vaccines.”

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Posted in Pathogen, pathogenic, Research, Shigella, Uncategorized