Category Archives: E.coli

Research – Mechanisms of Inhibition of Quorum Sensing as an Alternative for the Control of E. coli and Salmonella

MDPI

Quorum sensing (QS) is a process of cell–cell communication for bacteria such as E. coli and Salmonella that cause foodborne diseases, with the production, release, and detection of autoinducer (AI) molecules that participate in the regulation of virulence genes. All of these proteins are useful in coordinating collective behavior, the expression of virulence factors, and the pathogenicity of Gram-negative bacteria. In this work, we review the natural or synthetic inhibitor molecules of QS that inactivate the autoinducer and block QS regulatory proteins in E. coli and Salmonella. Furthermore, we describe mechanisms of QS inhibitors (QSIs) that act as competitive inhibitors, being a useful tool for preventing virulence gene expression through the downregulation of AI-2 production pathways and the disruption of signal uptake. In addition, we showed that QSIs have negative regulatory activity of genes related to bacterial biofilm formation on clinical artifacts, which confirms the therapeutic potential of QSIs in the control of infectious pathogens. Finally, we discuss resistance to QSIs, the design of next-generation QSIs, and how these molecules can be leveraged to provide a new antivirulence therapy to combat diseases caused by E. coli or SalmonellaView Full-Text

USA – Alabama warms of E. coli and Rotavirus cases in children

Food Poison Journal

The Alabama Department of Public Health (ADPH) is investigating four cases of E. coli O157:H7 and two cases of Rotavirus in younger children in Northeastern Alabama. ADPH regularly investigates clusters and outbreaks of communicable diseases as required by Notifiable Disease Rules in Alabama.

In 2021, ADPH investigated 113 cases of E. coli, shiga toxin-producing illness (includes O157:H7). People of any age can become infected with this germ, but very young children and the elderly are more likely to develop severe illness and kidney problems than others.

Research – Observational Study of the Impact of a Food Safety Intervention on Consumer Poultry Washing

Journal of Food Protection

This study was conducted to test the effectiveness of a consumer poultry washing educational intervention that included video observation of meal preparation with participants who self-reported washing poultry. Treatment group participants received three e-mail messages containing information that the U.S. Department of Agriculture has used on social media sites (video and infographics) related to poultry preparation, including advising against washing chicken. Participants were observed cooking chicken thighs (inoculated with traceable nonpathogenic Escherichia coli strain DH5α) and preparing a salad to determine whether they washed the chicken and the extent of cross-contamination to the salad and areas of the kitchen. After meal preparation, participants responded to an interview about food handling behaviors, including questions about the intervention for treatment group participants. Three hundred people participated in the study (158 control, 142 treatment). The intervention effectively encouraged participants not to wash chicken before cooking; 93% of treatment group participants but only 39% of control group participants did not wash the chicken (P < 0.0001). The high levels of E. coli DH5α detected in the sink and on the salad lettuce suggest that microbes transferred to the sink from the chicken, packaging, or contaminated hands are a larger cause for concern than is splashing contaminated chicken fluids onto the counter. Among chicken washers, 26 and 30% of the lettuce from the prepared salad was contaminated for the control and treatment groups, respectively. For nonwashers, 31 and 15% of the lettuce was contaminated for the control and treatment groups, respectively. Hand-facilitated cross-contamination is suspected to be a factor in explaining this resulting lettuce cross-contamination. This study demonstrates the need to change the frame of “don’t wash your poultry” messaging to instead focus on preventing contamination of sinks and continuing to emphasize the importance of hand washing and cleaning and sanitizing surfaces.

HIGHLIGHTS
  • The intervention was effective for convincing participants to not wash chicken before cooking.
  • High levels of the bacterial tracer were detected in the sink and on the salad lettuce.
  • Messaging should focus on hand washing and cleaning and sanitizing surfaces.

Research – New NARMS report shows rising resistance in Salmonella, Campylobacter

CIDRAP

The latest data from a national surveillance system that monitors foodborne bacterial pathogens for antimicrobial resistance (AMR) shows some concerning changes in resistance patterns among serotypes of Salmonella.

The findings come from the National Antimicrobial Resistance Monitoring Systems (NARMS) 2019 Integrated Summary, which combines data from the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and the US Department of Agriculture (USDA). The report provides a snapshot of resistance patterns found in bacteria isolated from humans, animals, raw meats from retail outlets (chicken, ground turkey, ground beef, and pork chops), and meat and poultry product samples collected at slaughtering facilities.

In addition to Salmonella, which causes an estimated 1.35 million illnesses and 26,500 hospitalizations each year, the NARMS report also includes resistance data on Campylobacter (1.5 million illnesses and 19,500 hospitalizations), Escherichia coli, and Enterococcus. NARMS monitors these bacteria to detect emerging resistance patterns to the antibiotics that are most important to human medicine, multidrug resistance, and specific resistance genes.

Increase in multidrug-resistant Salmonella serotype

Overall, the NARMS report shows that more than three fourths of the Salmonella isolates (78%) from humans were not resistant to any of the antibiotics tested, and that the overall level of resistance in humans remains relatively unchanged since 2018. However, the report also found rising resistance to ciprofloxacin—one of the three antibiotics used to treat severe Salmonella infections.

From 2018 to 2019, Salmonella with decreased susceptibility to ciprofloxacin increased from 9% to 11% in humans, from 18% to 31% in retail chicken, from 20% to 30% in chicken product samples, from 26% to 32% in chicken cecal content samples, and from 0% to 14% in retail pork samples.

The increase in resistance to ciprofloxacin among poultry isolates was primarily due to the increase in Salmonella Infantis, a multidrug-resistant (MDR) serotype that emerged in 2014.

The rise in Salmonella Infantis isolates was also behind an increase in MDR isolates found in retail chicken (from 20% to 32%) and in chicken product samples (22% to 29%). Up to 10 antimicrobial resistance (AMR) genes were found in some of the Salmonella Infantis isolates.

In addition, the NARMS report shows an increase in another MDR Salmonella serotype, I 4,[5],12:i:-, which is linked to pigs and has become an increasing public health concern in Europe and the United States. The percentage of MDR isolates from humans that are of the I 4,[5],12:i:- serotype rose from 7% in 2010 to 26% in 2019, and from 7% to 35% in swine samples.

NARMS data also show rising fluoroquinolone resistance in Campylobacter isolates. In humans, the proportion of ciprofloxacin-resistant Campylobacter isolates rose from 29% in 2018 to 34% in 2019 for Campylobacter jejuni and from 41% to 45% in C coli. Ciprofloxacin-resistant C jejuni isolated from chicken cecal contents (21% in 2018 to 26% in 2019) and chicken retail samples (20% to 22%) also rose.

Analysis of E coli isolates found increases in ceftriaxone resistance in sow cecal samples (3% in 2018 to 7% in 2019) and in retail pork (4% to 7%). Whole-genome sequencing of Salmonella and E coli from animals, animal products, and retail meats found that none harbored any of the MCR-1 through MCR-8 colistin-resistance genes.

Research – Microbiology and Epidemiology of Escherichia albertii—An Emerging Elusive Foodborne Pathogen

MDPI

Escherichia albertii, a close relative of E. coli, is an emerging zoonotic foodborne pathogen associated with watery diarrhea mainly in children and immunocompromised individuals. E. albertii was initially classified as eae-positive Hafnia alvei, however, as more genetic and biochemical information became available it was reassigned to its current novel taxonomy. Its infections are common under conditions of poor hygiene with confirmed transmission via contaminated water and food, mainly poultry-based products. This pathogen has been isolated from various domestic and wild animals, with most isolates being derived from birds, implying that birds among other wild animals might act as its reservoir. Due to the absence of standardized isolation and identification protocols, E. albertii can be misidentified as other Enterobacteriaceae. Exploiting phenotypes such as its inability to ferment rhamnose and xylose and PCR assays targeting E. albertii-specific genes such as the cytolethal distending toxin and the DNA-binding transcriptional activator of cysteine biosynthesis encoding genes can be used to accurately identify this pathogen. Several gaps exist in our knowledge of E. albertii and need to be bridged. A deeper understanding of E. albertii epidemiology and physiology is required to allow the development of effective measures to control its transmission and infections. Overall, current data suggest that E. albertii might play a more significant role in global infectious diarrhea cases than previously assumed and is often overlooked or misidentified. Therefore, simple, and efficient diagnostic tools that cover E. albertii biodiversity are required for effective isolation and identification of this elusive agent of diarrhea. View Full-Text

Research – Raw-milk cheeses: What are the associated health risks and what preventive measures can be taken?

ANSES

Salmonella, enterohaemorrhagic E. coli, Listeria monocytogenes – a wide range of bacteria can be found in the raw-milk cheeses and other raw-milk dairy products we consume. These are sometimes involved in cases of food poisoning, leading them to be recalled or withdrawn from the market. In order to further improve the control of these risks, ANSES has identified the types of raw-milk cheeses on which efforts should focus as a priority.

ANSES received a request from the Directorate General for Food to identify and classify the main bacterial hazards associated with the various types of raw-milk cheeses and other dairy products made from raw milk. The aim was also to assess the main sources of contamination and the means implemented to control the associated risks.

The main microbiological hazards in raw-milk cheeses and dairy products

In France over the last decade, 34%, 37% and 60% of outbreaks of salmonellosis, listeriosis and enterohaemorrhagic E. coli (EHEC) infections respectively have been linked to the consumption of raw-milk cheeses. While some bacteria can cause gastroenteritis symptoms (Salmonella spp. and Staphylococcus aureus), others can have much more serious consequences such as kidney failure (EHEC) or even death (L. monocytogenes, EHEC).

The main sources of these hazards are soft cheeses with a surface mould (such as Camembert, Brie and Crottin) and short-ripened uncooked pressed cheeses (such as Morbier, Reblochon and Saint-Nectaire). Next come soft washed-rind cheeses such as Munster and Maroilles.

Continue efforts to prevent microbiological risks, from farm to consumer

The means implemented to control microbiological risks in the main dairy sectors (cattle, sheep, goats), from the rearing stage to the consumption stage, were studied by the Agency. It concluded that:

At farm level, good animal husbandry and hygiene practices are well known in the various sectors. The efforts already well under way in terms of hygiene during milking and the management of mastitis should be continued;
At the production stage, levels of risk control are also very high; the Agency recommends continuing to implement good hygiene practices and to carry out self-checks in order to best anticipate any risk of an outbreak;
At consumer level, in order to avoid a foodborne infectious disease, it is essential to comply with the information on the packaging or that given by the seller concerning the temperature at which the cheese should be stored in the refrigerator and its use-by date. Lastly, ANSES reiterates its recommendation that pregnant women, immunocompromised individuals, people over the age of 65 and young children should avoid consuming raw-milk cheeses, with the exception of hard pressed cheeses such as Gruyère and Comté.

“For several years now, we have been seeing a strong commitment on the part of the various raw-milk cheese sectors to preventing microbiological risks. Thanks to the actions taken, levels of hygiene and risk control are now very high on farms. The self-checks implemented at the processing stage are able to identify a large number of problematic batches. However, there is still a residual risk and it is important to identify new ways of optimising the current control measures. For example, this could involve improving epidemiological investigations, identifying poor hygiene practices at an earlier stage, or communicating more with consumers”, explains Laurent Guillier, who coordinated ANSES’s expert appraisal.

Did you know?

Contrary to popular belief, removing the rind from a raw-milk cheese is not enough to protect yourself against bacteria, as these can be found everywhere in the cheese.

On the other hand, when raw-milk cheeses are well cooked, as in an oven-baked recipe, they no longer pose a health risk.

A new forthcoming expert appraisal
This work to classify raw-milk cheeses was a first step in responding to the formal request. The expert appraisal work is continuing, to evaluate the effectiveness of the various health measures such as the sorting of milk at farm level and self-checks at the production stage. The next step will be to identify priority work areas for further reducing microbiological risks.

Click to access BIORISK2019SA0033.pdf

Research – Harmless or deadly? New study examines evolution of E. coli

UTS

A new study, published in Nature Communications, suggests genetic material from E. coli bacteria in farm animals could be contributing to the evolution of deadly strains of E. coli in humans.

Genetic material from E. coli bacteria in farm animals could be contributing to the evolution of deadly pandemic strains of E. coli in humans, new research shows.

E. coli usually live as harmless bacteria in the gastrointestinal tracts of birds and mammals, including humans. They also reside, independent of a host, in environments such as water and soil, and in food products including chicken and turkey meat, raw milk, beef, pork and mixed salad.

These bacteria can cause disease if they possess or acquire factors that allow them survive in areas of the human body outside the gut.

E. coli is the primary source of urinary tract infections, a common reason for hospital admissions. It can also lead to sepsis, which kills 11 million people globally each year, and meningitis, an infection that affects the brain and spinal cord.

Dr Cameron Reid, from the University of Technology Sydney, said the aim of the study, recently published in Nature Communications, was to better understand the evolution and genomic characteristics of an emerging strain of E. coli known as ST58.

Research – Water application method influences survival or growth of Escherichia coli on bulb onions during field curing

FDA

The impact of water application method on bacterial survival at or after the final irrigation was evaluated in bulb onions during commercially relevant field-drying (curing). A three-strain rifampin-resistant cocktail of Escherichia coli was introduced to onions via a single overhead spray application in two separate trials (5.22 [trial 1] or 2.40 [trial 2] log CFU per onion) 2 to 3 days after the final irrigation. Onions were lifted from the soil 8 days after spray inoculation and, in some cases, foliage was removed (topping); onions remained in the field for an additional ca. 2 weeks (total ca. 3 weeks of curing). E. coli populations declined on the onions in the first 4 h after spray inoculation. E. coli was recovered from 48% (38 of 80) or 35% (28 of 80) of whole-onion enrichments at the end of curing in trials 1 or 2, respectively. Topping did not significantly impact the percentage of E. coli–positive onions detected at the end of curing. From 8 h to 21 days, E. coli populations on positive onions ranged from 1 CFU per onion to 7 log CFU per onion in both trials, representing a potential risk of E. coli growth with overhead application of contaminated water at the end of onion production. In trial 2, additional rows of onions were inoculated via a 22-cm subsurface or surface drip irrigation line (1.94 log CFU/mL for 2.5 h). E. coli was detected in 0 of 50 (subsurface) or 4 of 50 (surface) whole-onion enrichments 3 h after the initiation of drip irrigation. Positive onions were detected at days 1 (4 of 50) and 7 (1 of 50) with subsurface drip inoculation, and at days 1 (7 of 50), 7 (2 of 50), or 14 (2 of 50) with surface drip inoculation. E. coli was not detected in whole-onion enrichments at the end of curing when inoculated by subsurface (0 of 50) or surface (0 of 50) drip irrigation. Application of contaminated water through drip irrigation, when coupled with field curing, results in low rates of contamination of bulb onions at the time of harvest.

Research – Evaluation of Hygiene Indicators and Sampling Plan for Detecting Microbial Contamination in Health Functional Foods

Journal of Food Protection

This study aimed to monitor microbial contamination level in a variety of health functional foods and to establish new microbial criteria. Indicator organisms (i.e., aerobic bacteria, coliform bacteria, and Escherichia coli ) were monitored in 10 health functional food categories (743 items, 3,715 samples). The mean total aerobic counts of ginseng and Korean red ginseng were -0.35 and -0.74 log10 CFU/g; and their mean total coliform counts were -1.4 and -1.39 log10 CFU/g, respectively. In addition, the mean total coliform counts of fiber and protein products were -1.34 and -1.22 log10 CFU/g, respectively. However, no aerobic or coliform cells were detected in any other health functional food products (vitamins, minerals, probiotics, milk thistle extract, propolis, eicosapentaenoic acid, docosahexaenoic acid, or lutein products), and no E. coli was detected in any of the categories. These results can potentially be used to update the microbial criteria of the Health Functional Food Code.

Research – Enhanced antimicrobial effectiveness of synergistic mixtures of rambutan peel extract and cinnamon essential oil on food spoilage bacteria and bio-based food packaging

Wiley Online

Staph

This research aims to enhance antimicrobial activity of rambutan peel extract (RPE), by mixing with cinnamon essential oil (CEO). The mixture of RPE and CEO with different weight ratios (10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, and 0:10) had been prepared and the antimicrobial efficacy was tested. Nine strains of bacteria: Gram-positive bacteria (Bacillus sp., Enterococcus faecalisLeuconostoc sp., Micrococcus luteusStaphylococcus aureus, and Streptococcus sp.) and Gram-negative bacteria (Escherichia coliPseudomonas fluorescens, and Salmonella typhimurium) were selected as the representative of pathogenic and food spoilage bacteria. Mixing RPE with CEO in a ratio of 5:5 showed the best synergistic effect against those bacteria. Addition of RPE/CEO in a weight ratio of 5:5 improved the antimicrobial activity of whey protein isolated (WPI) films, and enhanced strength, stiffness, and water resistance of the film.