How human cells and pathogenic shigella engage

Posted on July 21, 2021 by Douglas Powell

One member of a large protein family that is known to stop the spread of bacterial infections by prompting infected human cells to self-destruct appears to kill the infectious bacteria instead, a new study led by UT Southwestern scientists shows. However, some bacteria have their own mechanism to thwart this attack, nullifying the deadly protein by tagging it for destruction.

The findings, published online on May 21/21 in Cell, could lead to new antibiotics to fight bacterial infections. And insight into this cellular conflict could shed light on a number of other conditions in which this protein is involved, including asthma, Type 1 diabetes, primary biliary cirrhosis, and Crohn’s disease.

“This is a wonderful example of an arms race between infectious bacteria and human cells,” says study leader Neal M. Alto, Ph.D., professor of microbiology at UTSW and a member of the Harold C. Simmons Comprehensive Cancer Center.

Previous research has shown that the protein, called gasdermin B (GSDMB), was different from other members of the mammalian gasdermin family. Related gasdermin proteins form pores in the membranes of infected cells, killing them while allowing inflammatory molecules to leak out and incite an immune response. However, GSDMB – found in humans but not in some other mammalian species, including rodents – doesn’t form pores in the membranes of cultured mammalian cells, leaving its target a mystery.

Using a novel screening technology, Alto and colleagues discovered that a protein toxin called IpaH7.8 from shigella flexneri, a bacterium that causes diarrheal disease, directly inhibits GSDMB. Biochemical experiments show that IpaH7.8 places a chemical tag on GSDMB that marks it for cellular destruction.

To understand why shigella flexneri rids human cells of GSDMB, the researchers placed GSDMB within synthetic mammalian and bacterial cell membranes. While GSDMB left the synthetic mammalian membranes unharmed, it poked holes in the bacterial membranes. Further investigation showed that immune cells called natural killer cells stimulate this process.

Alto notes that inhibiting the ability of shigella IpaH7.8 to counteract GSDMB could lead to new types of antibiotics. And because genetic variants of GSDMB have been linked to a variety of inflammatory diseases and cancer, better understanding this protein could lead to new treatments for these conditions too.

Crypto in cattle and humans in Ethiopia

Posted on July 19, 2021 by Douglas Powell

Cryptosporidium is an intracellular coccidian parasite causing gastrointestinal disturbances resulting in diarrhea in humans and animals. It is more frequently detected in calves and early childhood, and one of the major causes of mortality in low-income countries. National estimates of Cryptosporidium infection rate in cattle and humans are lacking in Ethiopia. Therefore, this systematic review and meta-analysis estimated the prevalence and assess the risk factors of Cryptosporidium infection in cattle and humans over 20 years.

Article searches were made using PubMed, HINARI, Research Gates, AJOLs and Google Scholar databases. Studies that met the inclusion criteria under the preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist were used. Random effects models and Inverse Variance Index were used to calculate the pooled prevalence of cryptosporidiosis and heterogeneity among studies, respectively. A total of 23 eligible studies published between 2000 and 2020 were selected for this study. The estimated pooled prevalence of cryptosporidiosis was found to be 16.2% and 11% in cattle and humans, respectively.

Ten Cryptosporidium species were documented with cattle and human-based studies. C. andersoni, C. parvum, C. bovis and C. ryanae were the reported species in cattle. Similarly, in humans, seven types of Cryptosporidium species (such as C. parvum, C. hominis, C. viatorum, C. felis, C. meleagridis, C. canis and C. xiaoi) was recorded. C. parvum and C. hominis were the dominant and responsible species for human illness. Using gp60 gene locus analysis, various zoonotic C. parvum subgenotypes were determined in humans; but it was limited in anthroponotic C. hominis.

In conclusion, the overall prevalence of Cryptosporidium infection in cattle and humans was high and linked with several risk factors. Thus, there is a need for further epidemiological and genetic diversity studies, and awareness of creations on the disease to provide strategies that mitigate the disease in cattle and humans.

Cryptosporidium infection in cattle and humans in Ethiopia: A systematic review and meta-analysis, 13 July 2021

Parasite Epidemiology and Control

Zewdu Seyoum, Tarekegn^a, Yeshifana Tigabu^a, Haileyesus Dejene^ab

https://doi.org/10.1016/j.parepi.2021.e00219

https://www.sciencedirect.com/science/article/pii/S2405673121000209

Listeriosis in England and Wales: Summary for 2019

Posted on March 15, 2021 by Douglas Powell

This report summarises the number and characteristics of confirmed cases of listeriosis in England and Wales in 2019:

142 cases of listeriosis were reported in England and Wales;
incidence rates of listeriosis were highest in people aged 80 years and over;
the crude incidence of listeriosis was lower in men than women, but reported cases among men aged 60 to 69 were 7 times higher than in women aged 60 to 69;
pregnancy-associated infections accounted for 17.6% of all reported cases and, a third of pregnancy-associated cases resulted in stillbirth or miscarriage;
among non-pregnancy associated cases of listeriosis, death was reported for 23 cases (19.7%), of whom 15 (12.8%) were known to have listeriosis recorded as a cause of death on the death certificate
incidence of listeriosis varied geographically, with the lowest incidence in East of England (0.14 per 100,000 population) and the highest in London (0.39 per 100,0000 population); and,
there were 4 listeriosis outbreaks investigated in England, including a national outbreak associated with the consumption of prepacked hospital sandwiches.

STEC on dairy farms

Posted on March 15, 2021 by Douglas Powell

One of my best friends used to be a dairy farmer, and he would always say, I’m not eating at McDonald’s, could be one of my former cows.

Shiga toxin-producing Escherichia coli (STEC) are foodborne bacterial pathogens, with cattle a significant reservoir for human infection. This study evaluated environmental reservoirs, intermediate hosts and key pathways that could drive the presence of Top 7 STEC (O157:H7, O26, O45, O103, O111, O121 and O145) on pasture-based dairy herds, using molecular and culture-based methods.

A total of 235 composite environmental samples (including soil, bedding, pasture, stock drinking water, bird droppings and flies and faecal samples of dairy animals) were collected from two dairy farms, with four sampling events on each farm. Molecular detection revealed O26, O45, O103 and O121 as the most common O-serogroups, with the greatest occurrence in dairy animal faeces (> 91%), environments freshly contaminated with faeces (> 73%) and birds and flies (> 71%). STEC (79 isolates) were a minor population within the target O-serogroups in all sample types but were widespread in the farm environment in the summer samplings.

Phylogenetic analysis of whole genome sequence data targeting single nucleotide polymorphisms revealed the presence of several clonal strains on a farm; a single STEC clonal strain could be found in several sample types concurrently, indicating the existence of more than one possible route for transmission to dairy animals and a high rate of transmission of STEC between dairy animals and wildlife.

Overall, the findings improved the understanding of the ecology of the Top 7 STEC in open farm environments, which is required to develop on-farm intervention strategies controlling these zoonoses.

Investigation of on-farm transmission routes for contamination of dairy cows with top 7 Escherichia coli O-serogroups

Environmental Microbiology

Rapp & C. M. Ross & P. Maclean & V. M. Cave & G. Brightwell

https://link.springer.com/article/10.1007/s00248-020-01542-5

FoodNet Canada, 2019

Posted on February 22, 2021 by Douglas Powell

The Public Health Agency of Canada’s (PHAC) FoodNet Canada surveillance system (no, not that one, right, that’s the Canadian television network that wanted to sue me over video associated with 2004’s cooking show paper) is pleased to present this tables and figures report which provides the annual results of our surveillance activities conducted in 2019. The report is based on findings from its sentinel sites in British Columbia, Alberta, and Ontario. It also provides preliminary findings from Quebec, representing a partial year due to their implementation part way through the year in July 2019. The report focuses on trends in enteric pathogen disease rates, as well as trends in the prevalence of these pathogens found on potential disease sources: retail meats, manure from food producing animals and water. It is our hope that this report will be used to inform and shape discussions on food safety issues regarding enteric diseases and their sources.

Key findings:

In 2019, Campylobacter and Salmonella remained the most common causes of human enteric illness in the FoodNet Canada sentinel sites.
Travel continues to be an important factor in the burden of enteric disease. In 2019, approximately 30% of all cases of enteric disease were associated with travel outside of Canada.
Exposure to retail meat products remains a potential source of infection for human enteric illness. However, decreases in the prevalence of certain pathogen-food combinations were observed in 2019. For example, Salmonella on frozen breaded chicken products significantly decreased in 2019 compared to 2018 and is likely associated with interventions implemented at the industry level in 2019.
Other exposures, such as the farm environment and water, are also possible sources of infection for human enteric illness, with differences noted between the sites. For example, Salmonella is commonly found in broiler chicken manure, however, the prevalence significantly increased in BC whereas it significantly decreased in the AB site in 2019, resulting in an overall significant decrease in the combined sites.
The majority of clinical cases of shigatoxigenic Escherichia coli (STEC) were domestically acquired in 2019, with a significant increase in both travel and endemic incidence rates, which is primarily driven by the AB sentinel site who test all STEC-confirmed stool samples for non-O157 serogroups.
In 2019, surface water sampling was initiated for the first time in the ON site for STEC testing. The prevalence of STEC in the ON site (27%) was similar to the combined BC and AB irrigation water prevalence in 2019 (28%). · Continued monitoring of human illness and the potential exposures is important to ensure the continued health and safety of Canadians. The collection and integration of information across all of FoodNet Canada surveillance components (human, retail, on-farm, and water) in an enhanced and standardized way allows for the analysis of subtype distributions among human cases and potential exposure sources over time. This report will be followed by a comprehensive annual report, which will include more extensive analyses of temporal trends and subtyping information for an integrated perspective on enteric disease from exposure to illness.

Testing for TSEs in the EU, 2019

Posted on November 19, 2020 by Douglas Powell

The European Union summary report on surveillance for the presence of transmissible spongiform encephalopathies (TSE) in 2019, 17 November 2020, EFSA:

This report presents the results of surveillance on transmissible spongiform encephalopathies (TSE) in cattle, sheep, goats, cervids and other species, and genotyping in sheep, carried out in 2019 by 28 Member States (MS), and by Iceland, Montenegro, North Macedonia, Norway, Serbia and Switzerland (non‐MS).

In total, 1,150,388 cattle were tested by MS, a 2.7% decrease from 2018 and 44,557 by the six non‐MS. Six cases of H‐BSE were reported by France (4) and Spain (2), and 1 L‐BSE by Poland. The number of H‐ BSE cases was the largest reported per year including the youngest ever case (5.5 years of age).

In total, 338,098 sheep and 143,529 goats were tested in the EU, an increase of 3.9% in both species compared with 2018. In sheep, 17 inconclusive cases by two MS and 997 cases of scrapie were reported: 911 classical (97 index cases (IC), one of ARR/ARR genotype and 98.7% with genotypes of susceptible groups) by seven MS, 86 atypical (AS) (80 IC) by 11 MS. Thirty‐one ovine scrapie cases were reported by Iceland and Norway. Random genotyping was only reported by eight MS: Cyprus excluded, 15.7% of genotyped sheep carried genotypes of susceptible groups. In goats, three inconclusive cases by two MS and 390 cases of scrapie were reported: 379 classical (24 IC) by six MS, 11 atypical (10 IC) by six MS.

The heterogeneous enforcement of a 3‐year surveillance programme for chronic wasting disease (CWD) in six MS (Estonia, Finland, Latvia, Lithuania, Poland and Sweden) resulted in the testing of 7,980 cervids and confirmation of three CWD cases in wild moose in Sweden. Other seven MS tested 2,732 cervids with no positive results. Norway tested 30,147 cervids in 2019, with two new moose cases. In total, 122 animals from four other species reported by three MS TSE tested negative.

US to miss foodborne disease reduction goals

Posted on July 20, 2020 by Douglas Powell

I’ve said this for years.

Need new messages, new strategy.

The American Veterinary Medical Association newsletter reports numbers of confirmed illnesses in humans resulting from common foodborne pathogens have risen or remained level for several years, putting the U.S. on track to miss 2020 reduction targets.

Better tests and more testing may help explain why the numbers have not fallen, but to reach its goals, the U.S. needs more work to reduce food contamination, according to authors of an article published this spring in the Centers for Disease Control and Prevention’s Morbidity and Mortality Weekly Report. Among the findings, the authors wrote that preliminary 2019 data show confirmed illness counts for Listeria, Salmonella, and Shigella have remained unchanged over several years, and confirmed illness counts for the other five pathogens tracked by the CDC’s Foodborne Diseases Active Surveillance Network increased.
“FoodNet surveillance data indicate that progress in controlling major foodborne pathogens in the United States has stalled,” the article states. “To better protect the public and achieve forthcoming Healthy People 2030 foodborne disease reduction goals, more widespread implementation of known prevention measures and new strategies that target particular pathogens and serotypes are needed.”

I saw the Hip at a bar in Waterloo, Ontario, Canada on this tour with my 6-month pregnant ex-wife.

Great show.

Ya don’t know unless ya test

Posted on June 18, 2020 by Douglas Powell

Ya can’t test your way to a safe food supply, but ya can test to verify your food safety plans are working.

Testing to Additional Raw Beef Products

AGENCY: Food Safety and Inspection Service, USDA.

ACTION: Notice and request for comments.

SUMMARY: The Food Safety and Inspection Service (FSIS) is announcing plans to expand its routine verification testing for six Shiga toxin-producing Escherichia coli (non-O157 STEC; O26, O45, O103, O111, O121, or O145) that are adulterants, in addition to the adulterant Escherichia coli (E. coli) O157:H7, to ground beef, bench trim, and raw ground beef components other than raw beef manufacturing trimmings (i.e., head meat, cheek meat, weasand (esophagus) meat, product from advanced meat recovery (AMR) systems, partially defatted chopped beef and partially defatted beef fatty tissue, low temperature rendered lean finely textured beef, and heart meat)(hereafter “other raw ground beef components”) for samples collected at official establishments. STEC includes non-O157 STEC; O26, O45, O103, O111, O121, or O145, that are adulterants, and E. coli O157:H7. Currently, FSIS tests only its beef manufacturing trimmings samples for these six non-O157 STEC and E. coli O157:H7; all This document is scheduled to be published in the Federal Register on 06/04/2020 and available online at federalregister.gov/d/2020-12073, and on govinfo.gov 2 other aforementioned raw beef products are presently tested for E. coli O157:H7 only.

FSIS also intends to test for these non-O157 STEC in ground beef samples that it collects at retail stores and in applicable samples it collects of imported raw beef products. FSIS is requesting comments on the proposed sampling and testing of ground beef, bench trim, and other raw ground beef components. FSIS will announce the date it will implement the new testing in a subsequent Federal Register notice. Additionally, FSIS is responding to comments on the November 19, 2014, Federal Register notice titled “Shiga Toxin Producing Escherichia coli (STEC) in Certain Raw Beef Products.” FSIS is also making available its updated analysis of the estimated costs and benefits associated with the implementation of its non-O157 STEC testing on raw beef manufacturing trimmings and the costs and benefits associated with the expansion of its non-O157 STEC testing to ground beef, bench trim, and other raw ground beef components.

Rates of FBI going nowhere

Posted on May 5, 2020 by Douglas Powell

Is unconditional love a real thing? Is it possible to maximize an individual’s goals and relationships at the same time? Is microbial foodborne illness still a thing?

Unconditional is a subjective word that means different things to different people.

Rather than going for the safe middle in conflict resolution, I have a therapist who says, go for the jugular: have a great relationship and go after great goals (note: it helps if you tell your partner what you want in terms of the relationship and goals).

Microbial foodborne illness rates in the U.S. have been stagnant for 15 years. It’s a thing, but it’s not clear who cares.

The Washington Post stated back in the day, “Between 1998 and 2004, illnesses reported by CDC that were caused by E. Coli, listeria, campylobacter and a few other bacteria decreased by 25 to 30 percent, perhaps because of improvements in the handling of meat and eggs. Since about 2004, however, the rate of these illnesses has basically remained steady.”

There’s lots of new media toys out there, but it’s the high-tech version of signs that say, “Employees Must Wash Hands.” Reposting press releases – especially in the absence of critical analysis — is a waste of bandwidth and resources. And there is no evidence it results in fewer sick people.

Last week, the U.S. Centers for Disease Control reiterated the incidence of most infections transmitted commonly through food has not declined for many years.

Incidence of infections caused by Listeria, Salmonella, and Shigella remained unchanged, and those caused by all other pathogens reported to FoodNet increased during 2019. Infections caused by Salmonella serotype Enteritidis, did not decline; however, serotype Typhimurium infections continued to decline.

New strategies that target particular serotypes and more widespread implementation of known prevention measures are needed to reduce Salmonella illnesses. Reductions in Salmonella serotype Typhimurium suggest that targeted interventions (e.g., vaccinating chickens and other food animals) might decrease human infections. Isolates are needed to subtype bacteria so that sources of illnesses can be determined.

I’ve been harping about the need for new messages and new media for 15 years – even did a road trip in 2009 with a number of talks stressing this point – with apparently little effect.

So maybe I’ll focus on relationships and being the best partner, father and person I can be.

Peace and love.

Preliminary incidence and trends of infections with pathogens transmitted commonly through food—foodborne diseases active surveillance network, 10 US sites, 2016-2019, 01 May 2020

Morbidity and Mortality Weekly Report pp.509-514

Danielle M. Tack, DVM¹; Logan Ray, MPH¹; Patricia M. Griffin, MD¹; Paul R. Cieslak, MD²; John Dunn, DVM³; Tamara Rissman, MPH⁴; Rachel Jervis, MPH⁵; Sarah Lathrop, PhD⁶; Alison Muse, MPH⁷; Monique Duwell, MD⁸; Kirk Smith, DVM⁹; Melissa Tobin-D’Angelo, MD¹⁰; Duc J. Vugia, MD¹¹; Joanna Zablotsky Kufel, PhD¹²; Beverly J. Wolpert, PhD¹³; Robert Tauxe, MD¹; Daniel C. Payne, PhD¹

https://www.cdc.gov/mmw/volumes/69/wr/mm6917a1.htm?s_cid=mm6917a1_w&deliveryName=USCDC_921-DM26943

Kansas veterinary medicine researchers develop new method to improve food safety

Posted on February 7, 2020 by Douglas Powell

From a press release, as if you couldn’t tell:

Faculty members from the Kansas State University College of Veterinary Medicine have developed a faster, more efficient method of detecting “Shiga toxin-producing E. coli,” or STEC, in ground beef, which often causes recalls of ground beef and vegetables.

“The traditional gold standard STEC detection, which requires bacterial isolation and characterization, is not amenable to high-throughput settings and often requires a week to obtain a definitive result,” said Jianfa Bai, section head of molecular research and development in the Kansas State Veterinary Diagnostic Laboratory.

The new method developed by Bai and colleagues requires only a day to obtain confirmatory results using a Kansas State University-patented method with the partition-based multichannel digital polymerase chain reaction system.

“We believe the new digital polymerase chain reaction detection method developed in this study will be widely used in food safety and inspection services for the rapid detection and confirmation of STEC and other foodborne pathogens,” said Jamie Henningson, director of the Kansas State Veterinary Diagnostic Laboratory.

When ingested through foods such as ground beef and vegetables, STEC can cause illnesses with symptoms including abdominal pain and diarrhea. Some illnesses caused by STEC may lead to kidney failure and can be life-threatening.

“Some E. coli strains do not produce Shiga toxins and thus do not affect human health as much,” said Xuming Liu, research assistant professor. “Because cattle feces and ground beef can contain harmless or less pathogenic E. coli along with STEC, the most commonly used polymerase chain reaction cannot identify pathogenic E. coli strains in a complex sample matrix.”

The new digital polymerase chain reaction test was developed for research and food safety inspections that require shorter turnaround and high throughput, without sacrificing detection accuracy.

“While the current, commonly used testing method is considered to be the gold standard, it is tedious and requires many days to obtain results that adequately differentiate the bacteria,” said Gary Anderson, director of the International Animal Health and Food Safety Institute at the K-State Olathe campus.

The study, “Single cell-based digital PCR detection and association of Shiga toxin-producing E. coli serogroups and major virulence genes,” which describes the test design and results, was published in the Journal of Clinical Microbiology.

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