E. coli persisters

Escherichia coli O157:H7 (EcO157) infections have been recurrently associated with produce. The physiological state of EcO157 cells surviving the many stresses encountered on plants is poorly understood. EcO157 populations on plants in the field generally follow a biphasic decay in which small subpopulations survive over longer periods of time. We hypothesized that these subpopulations include persister cells, known as cells in a transient dormant state that arise through phenotypic variation in a clonal population.

Using three experimental regimes (with growing, stationary at carrying capacity, and decaying populations), we measured the persister cell fractions in culturable EcO157 populations after inoculation onto lettuce plants in the laboratory. The greatest average persister cell fractions on the leaves within each regime were 0.015, 0.095, and 0.221%, respectively. The declining EcO157 populations on plants incubated under dry conditions showed the largest increase in the persister fraction (46.9-fold). Differential equation models were built to describe the average temporal dynamics of EcO157 normal and persister cell populations after inoculation onto plants maintained under low relative humidity, resulting in switch rates from a normal cell to a persister cell of 7.7 × 10−6 to 2.8 × 10−5 h−1. Applying our model equations from the decay regime, we estimated model parameters for four published field trials of EcO157 survival on lettuce and obtained switch rates similar to those obtained in our study. Hence, our model has relevance to the survival of this human pathogen on lettuce plants in the field. Given the low metabolic state of persister cells, which may protect them from sanitization treatments, these cells are important to consider in the microbial decontamination of produce.

IMPORTANCE Despite causing outbreaks of foodborne illness linked to lettuce consumption, E. coli O157:H7 (EcO157) declines rapidly when applied onto plants in the field, and few cells survive over prolonged periods of time. We hypothesized that these cells are persisters, which are in a dormant state and which arise naturally in bacterial populations. When lettuce plants were inoculated with EcO157 in the laboratory, the greatest persister fraction in the population was observed during population decline on dry leaf surfaces. Using mathematical modeling, we calculated the switch rate from an EcO157 normal to persister cell on dry lettuce plants based on our laboratory data. The model was applied to published studies in which lettuce was inoculated with EcO157 in the field, and switch rates similar to those obtained in our study were obtained. Our results contribute important new knowledge about the physiology of this virulent pathogen on plants to be considered to enhance produce safety.

Formation of Escherichia coli O157:H7 persister cells in the lettuce phyllosphere and application of differential equation models to predict their prevalence on lettuce plants in the field

08 November 2019

Applied and Environmental Microbiology

Daniel S. Munther, Michelle Q. Carter, Claude V. Aldric, Renata Ivanek, Maria T. Brandl

DOI: 10.1128/AEM.01602-19

https://aem.asm.org/content/86/2/e01602-19.abstract?etoc

Lettuce continues to be overrated: 7 sick in Maryland from E. coli linked to pre-packaged salad

The Maryland Department of Health says seven confirmed cases of E. coli infections have been linked to pre-packaged Caesar salads.

According to the department of health, the infections were identified in people who’d eaten Ready Pac Bistro Bowl Chicken Caesar Salad purchased at Sam’s Club stores in Maryland.

One person was hospitalized as a result of the E. coli O157 infection.

No deaths have been linked to it.

And there aren’t enough bagpipes and mandolins in rock.

23 sick from Romaine lettuce: Was FDA’s outbreak announcement delay inexcusable or sensible

I love Mondays in Australia because it’s Sunday in the U.S., football and hockey are on TV for background, the kid is at school when not in France, and I write (Sorenne painting in France).

Fourteen years ago, me and Chapman went on a road trip to Prince George (where Ben thought he would be eaten by bears) to Seattle, then to Manhattan, Kansas, where in the first week I met a girl, got a job, and then spinach happened.

Leafy greens are still covered in shit.

I am drowning in nostalgia, but things haven’t changed, and, as John Prine wrote, all the news just repeats itself.

Same with relationships.

Former U.S. Food and Drug Administration food safety chief, David Acheson, writes that on October 31, 2019, FDA announced a romaine lettuce E. coli O157:H7 outbreak for which the active investigation had ended and the outbreak appeared to be over. As such FDA stated there was no “current or ongoing risk to the public” and no avoidance of the produce was recommended.

Since that announcement, however, I have seen a number of articles condemning FDA and CDC. Why? Because the traceback investigation of the outbreak began in mid-September when CDC notified FDA of an illness cluster that had sickened 23 people across 12 states. So why the delay in announcing it to the public?

Despite the critical (and rather self-serving; always self-serving) stance on the “inexcusable” delay taken by a prominent foodborne illness attorney and his Food Safety “News” publication – which blasted a headline FDA “hid” the outbreak – my stance, having been an FDA official myself involved in outbreak investigations, is that the delay was practical and sensible.

Why? As FDA states right in its announcement:

When romaine lettuce was identified as the likely source, the available data indicated that the outbreak was not ongoing and romaine lettuce eaten by sick people was past its shelf life and no longer available for sale.

Even once romaine was identified as the likely cause, no common source or point of contamination was identified that could be used to further protect the public.

During the traceback investigation, the outbreak strain was not detected in any of the samples collected from farms, and there were no new cases.

Thus, neither FDA nor CDC identified any actionable information for consumers.

So, if it is not in consumers’ best interest to publicize an issue that no longer exists, why should they be driven away from a healthy food alternative? Why should unfounded unease be generated that will damage the industry, providing no benefit for consumers but ultimately impacting their pockets? There is just no upside to making an allegation without information. We’ve seen the impact on consumers and the industry when an announcement of a suspected food turns out to be incorrect; specifically “don’t eat the tomatoes” when it turned out to be jalapeno and serrano peppers. Having learned from such incidents, FDA’s approach is: If we don’t have a message that will help protect the public, then there is no message to be imparted.

So, rather than condemn FDA and CDC, I would commend them for getting the balance correct. And, perhaps, instead of any condemning, we should be working together to get the answers faster, to get outbreak data through better, faster, more efficient and coordinated traceability. Our entire system is too slow – a topic we have discussed many times in these newsletters.

I disagree.

The public and the scientific community need to be informed to prevent additional people from barfing.

I also rarely eat lettuce of any sort because it is overrated and the hygiene controls are not adequate.

Greek salad without lettuce is my fave.

Going public: Early disclosure of food risks for the benefit of public health

Mar.17

NEHA, Volume 79.7, Pages 8-14

Benjamin Chapman, Maria Sol Erdozaim, Douglas Powell

http://www.neha.org/node/58904

Often during an outbreak of foodborne illness, there are health officials who have data indicating that there is a risk prior to notifying the public. During the lag period between the first public health signal and some release of public information, there are decision makers who are weighing evidence with the impacts of going public. Multiple agencies and analysts have lamented that there is not a common playbook or decision tree for how public health agencies determine what information to release and when. Regularly, health authorities suggest that how and when public information is released is evaluated on a case-by-case basis without sharing the steps and criteria used to make decisions. Information provision on its own is not enough. Risk communication, to be effective and grounded in behavior theory, should provide control measure options for risk management decisions. There is no indication in the literature that consumers benefit from paternalistic protection decisions to guard against information overload. A review of the risk communication literature related to outbreaks, as well as case studies of actual incidents, are explored and a blueprint for health authorities to follow is provided.

Another reason to dislike sushi: First report of E. coli O157

AIMS: The aim of this study was to evaluate the microbiological quality of commercially prepared ready-to-eat (RTE) sushi by enumerating aerobic mesophilic bacteria (AMB) and thermotolerant coliforms (TC) and detecting Escherichia coli and Salmonella ssp. An isolate was identified as E. coli O157:H7 which was evaluated for its virulence and antimicrobial resistance profiling as well as its ability to form biofilms on stainless steel.

METHODS AND RESULTS: There were four sampling events in seven establishments, totalling 28 pools of sushi samples. Mean AMB counts ranged between 5·2 and 7·7 log CFU per gram. The enumeration of TC varied between 2·1 and 2·7 log MPN per gram. Salmonella ssp. were not detected, and one sample was positive for E. coli and was identified as E. coli O157:H7. To the best of our knowledge, this is the first report of E. coli O157:H7 in sushi samples in the world literature. This isolate presented virulence genes stx1, stx2, eae and hlyA. It was also susceptible to 14 antimicrobials tested and had the ability to form biofilms on stainless steel.

CONCLUSIONS: There is a need to improve the good hygiene practices adopted in establishments selling sushi in the city of Pelotas, Brazil. In addition, the isolated E. coli O157:H7 carries a range of important virulence genes being a potential risk to consumer health, as sushi is a RTE food. This isolate also presents biofilm formation ability, therefore, may trigger a constant source of contamination in the production line of this food.

SIGNIFICANCE AND IMPACT OF THE STUDY: The increase in the consumption of sushi worldwide attracts attention regarding the microbiological point of view, since it is a ready-to-eat food. To our knowledge, this was the first time that E. coli O157:H7 was identified in sushi samples.

First report of Escherichia coli O157:H7 in ready-to-eat sushi

21 September 2019

Journal of Applied Microbiology

Ramires T 1  Iglesias MA 2 Vitola HS 1 Núncio ASP 1 Kroning IS 1  Kleinubing NR 1 , Fiorentini ÂM 1  da Silva WP 1  

DOI: 10.1111/jam.14456 

https://europepmc.org/abstract/MED/31541508

ProMed: 3 women hospitalized with E. coli O157, Wisconsin, RFI

Over the past 5 days, our health care facility in northwest Wisconsin, USA, has seen 3 women hospitalized with E. coli O157 infection. All presented with significant abdominal pain without fever and watery diarrhea which in 2 progressed to bloody diarrhea. None of the 3 have manifested any evidence of hemolytic-uremic syndrome. Both of the women seen by the Infectious Diseases service stated that their diet contains a lot of salads.

We would appreciate any reports of upswings in the number of cases of this process in the upper Midwest USA or elsewhere.

Salmonella, E. coli O157, Listeria, Campy: 1.9 million foodborne illnesses in US per year

In an ongoing effort to understand sources of foodborne illness in the United States, the Interagency Food Safety Analytics Collaboration (IFSAC) collects and analyzes outbreak data to produce an annual report with estimates of foods responsible for foodborne illnesses caused by pathogens. The report estimates the degree to which four pathogens – Salmonella, E. coli O157, Listeria monocytogenes, and Campylobacter – and specific foods and food categories are responsible for foodborne illnesses.

The Centers for Disease Control and Prevention (CDC) estimates that, together, these four pathogens cause 1.9 million foodborne illnesses in the United States each year. The newest report (PDF), entitled “Foodborne illness source attribution estimates for 2017 for Salmonella, Escherichia coli O157, Listeria monocytogenes, and Campylobacter using multi-year outbreak surveillance data, United States,” can be found on the IFSAC website.

The updated estimates, combined with other data, may help shape agency priorities and inform the creation of targeted interventions that can help to reduce foodborne illnesses caused by these pathogens. As more data become available and methods evolve, attribution estimates may improve. These estimates are intended to inform and engage stakeholders and to improve federal agencies’ abilities to assess whether prevention measures are working.

Foodborne illness source attribution estimates for 2017 for salmonella, Escherichia coli O157, listeria monocytogenes, and campylobacter using multi-year outbreak surveillance data, United States, Sept.2019

CDC, FDA, USDA-FSIS

https://www.cdc.gov/foodsafety/ifsac/pdf/P19-2017-report-TriAgency-508.pdf?deliveryName=DM10264

Pregnant mum gets Salmonella at same hotel where girl ‘got E. coli’ and later died

A pregnant mum has told of her fears for her unborn baby after contracting salmonella at the same hotel where a mum claims her two-year-old daughter contracted E. coli and later died.

Emma Broadhurst was six months pregnant when she flew out to Turkey with friends for a 7-night stay at the Crystal Sunset Luxury Resort and Spa, east of the city of Antayla, at the start of September.

But, according to Andy Rudd of The Mirror, within days of arriving she fell unwell suffering from chronic diarrhea and became dehydrated and lost weight.

Just over 24 hours later her best friend’s seven-year-old son, Kailan, also fell ill with diarrhea and on their return to the UK his mum, Emma McComb, fell ill and Kailan was left ‘screaming in agony’ and projectile vomiting.

All three, who shared a room while on holiday, were then diagnosed with salmonella poisoning after stool samples were sent for testing by their local GP, claims Emma.

The friends stayed in the same hotel where two-year-old Allie Birchall and her family holidayed before little Allie was taken ill before passing away having contracted E. coli.

All members of her family, from Wigan, Greater Manchester, suffered from gastric symptoms including stomach cramps and diarrhoea during their 10-day stay with Jet 2.

Allie’s condition became so severe she was rushed to hospital after the family returned to the UK.

Her parents had to make the heartbreaking decision to switch off her life support on August 3.

Girl, 4, left fighting for life after getting E. coli O157 on Isle of Wight trip

A four-year-old girl was left fighting for her life after contracting the deadly E.coli infection after a trip to the Isle of Wight.

Isla Grainger had to be put in an induced coma in intensive care after the harmful bug caused her kidneys to fail.

Pippa Allen-Kinross of the Mirror reports Isla spent 17 days in hospital and is now recovering at home, but is still not well enough to go to school.

She began to have diarrhoea and sickness after a weekend trip to the Isle of Wight with her mum Lauren Aspery, 21, and mum’s partner Lewis Keith.

The family visited a petting zoo, arcades and a beach in Sandown on the island before Isla became unwell.

But, as yet, they do not know where the infection came from.

Mum Lauren, who lives in Whiteley near Fareham, also had painful stomach aches and nausea.

After Isla stopped eating and struggled to go to the toilet for three days, Lauren took her daughter to the emergency department at Southampton General Hospital.

The little girl was rushed into emergency surgery to insert a catheter and begin urgent dialysis after tests revealed she had E.coli O157.

Medics realised the E.coli had developed into hemolytic uremic syndrome, affecting Isla’s blood cells and vessels and resulting in kidney failure.

She had to undergo surgery to remove a twisted catheter and was later moved to intensive care and placed in an induced coma.

Devastated Lauren was left terrified she would lose her daughter, as Isla’s condition quickly became a “matter of life or death”.

She said: “It was terrifying. I thought the worst and that we were going to lose our little girl.

  “I really believed this was just a bad case of sickness.

“The doctor took a breath and told us that ‘Isla is very, very poorly, much more sick than we thought’.

11 sick: E. coli O157 outbreak linked to Minnesota state fair

The Minnesota State Fair has been connected to an outbreak of an E. coli strain, according to the Minnesota Department of Health (MDH).

To date, disease doctors have identified 11 cases of E. coli 0157 among Minnesotans who were at the State Fair between Aug. 25 and Sept. 2. All of them fell ill between Aug. 29 and Sept. 6.

Ages of those sickened range from 2 to 43 years old. Six of the cases required the patient to be hospitalized, including one person developing hemolytic uremic syndrome, which the MDH says is a potentially fatal complication.

One person is still in a hospital being treated.

Investigators are working to determine the source of the outbreak, with evidence so far indicating that it most likely began with contact with livestock.

Most of the 11 patients visited the Miracle of Birth exhibit and made physical contact with calves, goats, sheep or piglets, but others suffering from the E. coli strain did not make direct contact with animals, leading the MDH to consider the possibility that those people made contact with contaminated surfaces.

“This serves as a strong reminder to always wash your hands after being around livestock and their enclosures,” the MDH says.

Fortunately, there is “little chance” of ongoing exposure to the strain since the fair has ended.

Erdozain GKukanich KChapman BPowell D. 2012. Observation of public health risk behaviours, risk communication and hand hygiene at Kansas and Missouri petting zoos – 2010-2011. Zoonoses Public Health. 2012 Jul 30. doi: 10.1111/j.1863-2378.2012.01531.x.

Observation of public health risk behaviors, risk communication and hand hygiene at Kansas and Missouri petting zoos – 2010-2011Outbreaks of human illness have been linked to visiting settings with animal contact throughout developed countries. This paper details an observational study of hand hygiene tool availability and recommendations; frequency of risky behavior; and, handwashing attempts by visitors in Kansas (9) and Missouri (4), U.S., petting zoos.

Handwashing signs and hand hygiene stations were available at the exit of animal-contact areas in 10/13 and 8/13 petting zoos respectively. Risky behaviors were observed being performed at all petting zoos by at least one visitor. Frequently observed behaviors were: children (10/13 petting zoos) and adults (9/13 petting zoos) touching hands to face within animal-contact areas; animals licking children’s and adults’ hands (7/13 and 4/13 petting zoos, respectively); and children and adults drinking within animal-contact areas (5/13 petting zoos each). Of 574 visitors observed for hand hygiene when exiting animal-contact areas, 37% (n=214) of individuals attempted some type of hand hygiene, with male adults, female adults, and children attempting at similar rates (32%, 40%, and 37% respectively). Visitors were 4.8x more likely to wash their hands when a staff member was present within or at the exit to the animal-contact area (136/231, 59%) than when no staff member was present (78/343, 23%; p<0.001, OR=4.863, 95% C.I.=3.380-6.998). Visitors at zoos with a fence as a partial barrier to human-animal contact were 2.3x more likely to wash their hands (188/460, 40.9%) than visitors allowed to enter the animals’ yard for contact (26/114, 22.8%; p<0.001, OR= 2.339, 95% CI= 1.454-3.763).

Inconsistencies existed in tool availability, signage, and supervision of animal-contact. Risk communication was poor, with few petting zoos outlining risks associated with animal-contact, or providing recommendations for precautions to be taken to reduce these risks.

 

Ripple: Arizona scientists to examine food safety practices after E. coli outbreak

In the spring of 2018, an E. coli O157 outbreak linked to romaine lettuce grown in the Yuma, Arizona area resulted in 210 reported illnesses from 36 states, 96 hospitalizations, 27 cases of hemolytic uremic syndrome (HUS) and five deaths.

The U.S. Food and Drug Administration has launched a new initiative with support from the Arizona Department of Agriculture, and in conjunction with the University of Arizona Cooperative Extension, the Wellton-Mohawk Irrigation and Drainage District (WMIDD), and members of the Yuma area leafy greens industry to better understand the ecology of human pathogens in the environment in the Yuma agricultural region. This initiative will be a multi-year study which will focus on how these pathogens survive, move and possibly contaminate produce prior to harvest. 

While the FDA, the Arizona Department of Agriculture and other state partners conducted an environmental assessment from June through August 2018 that narrowed the scope of the outbreak, the specific origin, the environmental distribution and the potential reservoirs of the outbreak strain remain unknown.

Between 2009 and 2017, FDA and partners at CDC identified 28 foodborne STEC outbreaks with known or suspected links to leafy greens. Like a lot of fresh produce, leafy greens are often eaten raw without a kill-step, such as cooking, that could eliminate pathogens that may be present.

Sounds like Yuma growers could use a Box of Rain. Or maybe more knowledge of the microbial ripple effect. May death be groovy for you, long-time Grateful Dead collaborator and lyricist Robert Hunter, who passed on Tuesday, aged 78.