CDC Reports Salmonella Reading Outbreak: Urges Food Preparation Precautions

MedicalResearch.com Interview with:
wash-hands-well . CDC wellAaron E. Glatt, MD, FACP, FIDSA, FSHEA

Chairman, Department of Medicine & Hospital Epidemiologist
South Nassau Communities Hospital
Clinical Professor of Medicine
Icahn School of Medicine at Mount Sinai
Oceanside, NY 11572 

MedicalResearch.com: What is the background for the CDC alert regarding a multistate outbreak of multidrug-resistant Salmonella Reading infections linked to raw turkey products?   Is this Salmonella strain different or more dangerous than other Salmonella food poisoning outbreaks? 

Response: The CDC has reported that as of yesterday, there have been 90 people infected with Salmonella Reading from 26 states. No deaths have been reported, but 40 patients to date required hospitalization. There was a previous outbreak of S. Reading in 2016 related to contaminated alfalfa sprouts, but this organism is not that much different nor is it more virulent than many other salmonella strains.  Continue reading

Salivary Peptide Protects Against E. Coli Diarrhea

MedicalResearch.com Interview with:

Esther Bullitt, Ph.D. Associate Professor Dept. of Physiology & Biophysics Boston University School of Medicine Boston, MA  02118-2526

Dr. Bullitt

Esther Bullitt, Ph.D.
Associate Professor
Dept. of Physiology & Biophysics
Boston University School of Medicine
Boston, MA  02118-2526 

MedicalResearch.com: What is the background for this study?

Response:      We know that saliva has properties that allow us to swallow easily, and to help prevent gum disease and infections in the mouth. But is that really the only use for the 1-2 liters (1-2 quarts) of saliva we produce every day?  We decided to test whether a component of saliva, Histatin-5, can help prevent diarrheal disease (Traveler’s Diarrhea by Enterotoxigenic Escherichia coli (ETEC)) that is caused by bacteria commonly found in contaminated food and water.

ETEC are bacteria that have hundreds of thin hair-like fibers on their surface, called pili. These bacteria bind specifically to the surface of the gut using these pili, and the bacteria need to stay bound long enough to initiate disease. Studies by Mike Levine’s group in the 1970’s showed that pili are necessary for enterotoxigenic Escherichia coli (ETEC) to cause disease. No adhesion, no disease.

One aid to remaining bound is the unwinding and rewinding of the pili. These helical fibers can unwind up to 8 times their original length, acting as shock absorbers during fluid flow.   Continue reading

Better Data Allows IFSAC and CDC To Identify Sources of Food Poisoning

MedicalResearch.com Interview with:

National Institute of Allergy and Infectious Diseases (NIAID)

NIAID image of salmonella invading an immune cell

LaTonia Richardson, PhD, Statistician
Division of Foodborne, Waterborne, and Environmental Diseases, Enteric Diseases Epidemiology Branch
CDC

MedicalResearch.com: Who is IFSAC?

Response: The Interagency Food Safety Analytics Collaboration (IFSAC) was created in 2011 by three federal agencies—the Centers for Disease Control and Prevention (CDC), the U.S. Food and Drug Administration (FDA), and the U.S. Department of Agriculture’s Food Safety and Inspection Service (USDA-FSIS)—to improve coordination of federal food safety analytic efforts and address cross-cutting priorities for food safety data collection, analysis, and use.  The current focus of IFSAC’s activities is foodborne illness source attribution, defined as the process of estimating the most common food sources responsible for specific foodborne illnesses. For more information on IFSAC, visit https://www.cdc.gov/foodsafety/ifsac/index.html.

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Whole Genome Sequencing Speeds Analysis of Shigella Outbreak in California

Dr-Varvara-Kozyreva.jpg

Dr. Varvara Kozyreva

MedicalResearch.com Interview with:
Varvara Kozyreva, PhD
Research Scientist Supervisor I
Genotyping Unit
Foodborne & Waterborne Diseases Section (FWDS)
Microbial Diseases Laboratory Program (MDL)
Division of Communicable Disease Control (DCDC)
Center for Infectious Diseases (CID)
California Department of Public Health (CDPH)
Richmond, CA 94804
California Department of Pubic Health

MedicalResearch.com: What is the background for this study?

CDPH Response: Two large shigellosis outbreaks occurred in San Diego and San Joaquin Counties of California in 2014-2015.

Shigellosis is caused by bacteria of Shigella genus and manifests itself as abdominal pain, diarrhea and other gastrointestinal symptoms. Each year, shigellosis causes around 500,000 infections, 6,000 hospitalizations and 70 deaths in the U.S. The shigellosis outbreaks in California were caused by a rare strain of Shiga-toxin producing Shigella sonnei bacteria. Shigella sonnei normally causes a relatively mild disease and is not known to produce Shiga-toxin. The emergence of this Shiga-toxin producing strain in California was unusual and concerning that shigellosis could become more severe in the future.

The California Department of Public Health Microbial Diseases Laboratory in collaboration with UC Davis tried to understand the origin of the Shigella sonnei strains circulating in California, how the bacteria acquired the Shiga-toxin gene and antibiotic resistance, as well as the relationships of California strains to other lineages around the world. This was the first major whole-genome study of Shigella sonnei bacteria in North America. In order to accomplish this we have sequenced and analyzed genomes of the recent outbreak strains as well as historical Shigella sonnei isolates from our archive going back as far as 1980. We also compared the genomes of California bacteria to other Shigella sonnei genomes from around the world. Among recent isolates we found two distinct outbreak populations: the Shiga-toxin producing strain primarily localized to San Diego and the San Joaquin Valley area, and the strain from the San Francisco Bay Area remarkable for its resistance to broad range of antibiotics.

MedicalResearch.com:  What are the main findings?

CDPH Response: Comprehensive analysis of genomes revealed a common origin of the toxin-producing strains of Shigella sonnei and their connection to earlier strains circulating in California. We learned that these microorganisms were not introduced to California but have originated locally.

It appeared that the toxin gene was introduced to Shigella sonnei with the Shiga-toxin encoding bacteriophage, the virus of bacteria, which interjected itself into Shigella sonnei genome. Most likely this happened via genetic exchange with Escherichia coli and other Shigella species. Furthermore, the bacteriophage in Shigella sonnei from California was very similar to a bacteriophage of Escherichia coli strain, which has caused a large outbreak in Europe in 2011.

 MedicalResearch.com: What should readers take away from this report?

CDPH Response: Whole Genome Sequencing (WGS) of Shigella sonnei allowed in-depth analysis of outbreak strains in California. The knowledge helped strengthen earlier epidemiological analysis of the outbreaks and understand the emerging trends in Shigella sonnei populations circulating in California.

The recent shigellosis outbreaks in California are characterized by two trends: 1) an acquisition of a new virulence factor (Shiga-toxin) by a local bacteria and 2) introduction of the antibiotic-resistant strain from abroad. It demonstrates two possible ways for the pathogens of high public health concern to emerge. This highlights the importance of monitoring the emergence and dissemination of the virulence and antibiotic resistance genetic determinants as well as shifts in local pathogen populations and flow of the bacterial strains between the countries and continents.

MedicalResearch.com: What recommendations do you have for future research as a result of this study?

CDPH Response:  Whole Genome Sequencing (WGS) of Shigella sonnei allowed in-depth analysis of outbreak strains in California. The knowledge helped strengthen earlier epidemiological analysis of the outbreaks and understand the emerging trends in Shigella sonnei populations circulating in California.

The recent shigellosis outbreaks in California are characterized by two trends: 1) an acquisition of a new virulence factor (Shiga-toxin) by a local bacteria and 2) introduction of the antibiotic-resistant strain from abroad. It demonstrates two possible ways for the pathogens of high public health concern to emerge. This highlights the importance of monitoring the emergence and dissemination of the virulence and antibiotic resistance genetic determinants as well as shifts in local pathogen populations and flow of the bacterial strains between the countries and continents.

MedicalResearch.com: Is there anything else you would like to add:
CDPH Response:
1. Additional genome analysis of Shigella sonnei is needed to find out if other bacterial traits influence their pathogenic properties.
2. Researchers should foster communications with the healthcare professionals to increase awareness about the potential for serious infectious due to Shigella sonnei.
3. More widespread use of Whole Genome Sequencing (WGS) in public health laboratories would help outbreak investigations, characterization of pathogenic properties of the bacteria and detection of antibiotic resistance genes. This would create a more complete picture of the bacterial world surrounding us, and in turn, help to protect public health

Citation:

Recent Outbreaks of Shigellosis in California Caused by Two Distinct Populations of Shigella sonnei with either Increased Virulence or Fluoroquinolone Resistance
Varvara K. Kozyreva, Guillaume Jospin, Alexander L. Greninger, James P. Watt, Jonathan A. Eisen, Vishnu Chaturvedi
Melanie Blokesch, Editor
DOI: 10.1128/mSphere.00344-16

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions.

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More Multistate Foodborne Outbreaks Identified With Better Surveillance and Centralized Food Processing

MedicalResearch.com Interview with:
Sam Crowe, PhD, MPH

Epidemic Intelligence Service Officer
Enteric Diseases Epidemiology Branch
Division of Foodborne, Waterborne, and Environmental Diseases
Centers for Disease Control and Prevention

Medical Research: What were the leading causes of multistate foodborne outbreaks and the most common contaminated foods during the study period?

Dr. Crowe: Salmonella, Shiga toxin-producing Escherichia coli, and Listeria monocytogenes were the leading pathogens causing multistate foodborne outbreaks. In order of frequency, fruits, vegetable row crops, beef, sprouts, and seeded vegetables were the leading contaminated foods.

Medical Research: How severe are multistate foodborne outbreaks?

Dr. Crowe: From 2010 through 2014, multistate foodborne outbreaks accounted for only 3% of all U.S. foodborne outbreaks detected, but caused over one third of the hospitalizations and more than half of the deaths.

Medical Research: Are these outbreaks occurring more frequently?

Dr. Crowe: Multistate foodborne outbreaks are being identified more often in the United States because of better surveillance. Greater centralization of food processing and distribution practices also could be increasing the frequency and size of multistate foodborne outbreaks. This is why your business should Look for Ruggedised Industrial Pointing Devices Today, to ensure your business is staying up with the industry standards.

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Spinach Bleach Contours May Prevent Adequate Decontamination

Nichola Kinsinger, Ph.D Postdoctoral Researcher, Chemical & Environmental Engineering University of California, Riverside USDA National Institute for Food and Agricultural Postdoctoral Fellow DoD Office of Naval Research National Defense Science and Engineering Graduate Research Fellow EIT (Chemical Engineering)MedicalResearch.com Interview with:
Nichola Kinsinger, Ph.D
Postdoctoral Researcher, Chemical & Environmental Engineering
University of California, Riverside
USDA National Institute for Food and Agricultural Postdoctoral Fellow
DoD Office of Naval Research National Defense Science and Engineering Graduate Research Fellow, EIT (Chemical Engineering)

Medical Research: What is the background for this study? What are the main findings?

Dr. Kinsinger: Outbreaks observed in produce are becoming increasing common possibly due to contaminated irrigation waters or contaminated waters used during processing.  In 2006 California had spinach-borne E. coli outbreak that impacted 26 states and 200 confirmed sickened.  Leafy greens account for 20% of the outbreaks alone and are of increased concern since they are frequently consumed raw. These outbreaks drew our attention over the past few years and we started applying methods originally developed for studying bacterial adhesion on engineered surfaces to the issue of food safety.  Although food safety is a new area of study for our lab, the project is based upon the concept of pathogen adhesion transport which has been the focus of my advisor’s lab for many years previously.  Rather than the previous scenario looking at pathogen interaction with engineered or mineral surfaces, we are looking at a spinach leaf instead.

salad-cdc-image

We are using a parallel plate flow chamber system developed by Professor Sharon Walker to evaluate the real time attachment and detachment of the pathogens to the spinach epicuticle layer (surface layer of the leaf) in realistic water chemistries and flow conditions.  Subsequently we can evaluate the efficacy of the rinsing process to kill the bacteria that may remain on the leaf.  Initially we were finding that at low concentrations of bleach, bacteria will detach from the leaf surface allowing for potential cross-contamination later in the process.   However above 500ppb we observed 100% of the attached bacterial cells are killed.

So how in commercial rinsing operations that use bleach concentration ranging from 50-200ppm result in outbreaks?  Through this study we analyzed the topography of the leaf and modeled the concentration gradient across the surface of a leaf based on commercial rinsing practices.  We found that even at high bleach concentrations within rinse water result in low bleach concentrations at the leaf surface on the order of 5-1000 ppb bleach, which in our study has shown to that the bacteria can survive when attached to the leaf and/or detach causing concern for cross-contamination.   In this case the very disinfection processes intended to clean, remove, and prevent contamination was found to be a potential pathway to amplifying foodborne outbreaks.

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