Vibrio in seafood goes up

There has been an increase in reported outbreaks and cases of foodborne disease attributed to pathogenic Vibrio species. As a result, there have been several instances where the presence of pathogenic Vibrio spp. in seafood has led to a disruption in international trade.

The number of Vibrio species being recognized as potential human pathogens is increasing. The food safety concerns associated with these microorganisms have led to the need for microbiological risk assessment to support risk management decision making for their control.

Vibrio parahaemolyticus is considered to be part of the autochthonous microflora in the estuarine and coastal environments in tropical to temperate zones. Food safety concerns have been particularly evident with V. parahaemolyticus. There have been a series of pandemic outbreaks of V. parahaemolyticus foodborne illnesses due to the consumption of seafood. In addition, outbreaks of V. parahaemolyticus have occurred in regions of the world where it was previously unreported. The vast majority of strains isolated from patients with clinical illness produce a thermostable direct haemolysin (TDH) encoded by the tdh gene. Clinical strains may also produce a TDH-related haemolysin (TRH) encoded by the trh gene. It has therefore been considered that those strains that possess the tdh and/or trh genes and produce TDH and/or TRH should be considered those most likely to be pathogenic. V. vulnificus can occasionally cause mild gastroenteritis in healthy individuals following consumption of raw bivalve molluscs. It can cause primary septicaemia in individuals with chronic pre-existing conditions, especially liver disease or alcoholism, diabetes, haemochromatosis and HIV/AIDS. This can be a serious, often fatal, disease with one of the highest fatality rates of any known foodborne bacterial pathogen.

The 41st Session of the Codex Committee on Food Hygiene (CCFH) requested FAO/WHO to convene an expert meeting to address a number of issues relating to V. parahaemolyticus and V. vulnificus including:

  • conduct validation of the predictive risk models developed by the United States of America based on FAO/WHO risk assessments, with a view to constructing more applicable models for wider use among member countries, including adjustments for strain virulence variations and ecological factors; xi
  • review the available information on testing methodology and recommend microbiological methods for Vibrio spp. used to monitor the levels of pathogenic Vibrio spp. in seafood and/or water;
  • conduct validation of growth rates and doubling times for V. parahaemolyticus and V. vulnificus in Crassostrea virginica (Eastern or American oyster) using strains isolated from different parts of the world and different bivalve molluscan species.

The requested expert meeting was held on 13-17 September 2010, and this report is the outcome of this meeting. Rather than undertaking a validation exercise, the meeting considered it more appropriate to undertake an evaluation of the existing risk calculators with a view to determining the context to which they are applicable and potential modifications that would need to be made to extend their application beyond that context. A simplified calculator tool could then be developed to answer other specific questions routinely. This would be dependent on the availability of the appropriate data and effort must be directed towards this. The development of microbiological monitoring methods, particularly molecular methods for V. parahaemolyticus and V. vulnificus is evolving rapidly. This means the identification of any single method for the purposes of monitoring these pathogens is challenging and also of limited value as the method is likely to be surpassed within a few years. Therefore, rather than making any single recommendation, the meeting considered it more appropriate to indicate a few of the monitoring options available while the final decision on the method selected will depend to a great extent on the specific purpose of the monitoring activity, the cost, the speed with which results are required and the technical capacity of the laboratory.

The meeting considered that monitoring seawater for V. parahaemolyticus and V. vulnificus in bivalve growth and harvest areas has limited value in terms of predicting the presence of these pathogens in bivalves. A linear relationship between levels of the vibrios in seawater and bivalves was not found and whatever relationship does exist can vary between region, the Vibrio spp. etc. Also, the levels of Vibrio species of concern in seawater tend to be very low. This presents a further challenge as the method used would need to have an appropriate level of sensitivity for their detection. Nevertheless, this does not preclude the testing of seawater for these vibrios; for example, in certain situations testing can provide an understanding of the aquatic microflora in growing areas. Monitoring of seafood for these pathogenic vibrios was considered the most appropriate way to get insight into the xii levels of the pathogens in these commodities at the time of harvest. Monitoring on an ongoing basis could be expensive, so consideration could be given to undertaking a study over the course of a year and using this as a means to establish a relationship between total and pathogenic V. parahaemolyticus and V. vulnificus in the seafood and abiotic factors such as water temperature and salinity. Once such a relationship is established for the harvest area of interest measuring these abiotic factors may be a more cost-effective way of monitoring.

The meeting undertook an evaluation exercise rather than attempting to validate the existing growth models. The experts considered the JEMRA growth model for V. vulnificus and the FDA growth model for V. parahaemolyticus were appropriate for estimating growth in the American oyster (Crassostrea virginica). The JEMRA growth model for V. vulnificus was appropriate for estimating growth in at least one other oyster species, Crassostrea ariakensis. The FDA model for V. parahaemolyticus was also appropriate for estimating growth in at least one other oyster species, Crassostrea gigas, but was not appropriate for predicting growth in the Sydney rock oyster (Saccostrea glomerata). There was some evidence that the V. parahaemolyticus models currently used over predict growth at higher temperatures (e.g. > 25 °C) in live oysters. This phenomenon requires further investigation. Growth model studies were primarily undertaken using natural populations of V. parahaemolyticus as these were considered to be the most representative. Data were limited and inconsistent with respect to the impact of the strain on growth rate although recent studies in live oysters suggest differences exist between populations possessing tdh/trh (pathogenic) versus total or non-pathogenic populations of V. parahaemolyticus.

There was no data to evaluate the performance of the growth models in any other oyster species or other filter feeding shellfish or other seafood and as such its use in these products could not be supported. If the models are used there should be a clear understanding of the associated uncertainty. This indicated a data gap which needs to be addressed before the risk assessments could be expanded in a meaningful manner.

Risk assessment tools for vibrio parahaemolyticus and vibrio vulnificus associated with seafood, 2020

FAO and WHO

https://apps.who.int/iris/bitstream/handle/10665/330867/9789240000186-eng.pdf?sequence=1&isAllowed=y

WHO chimes in: Risk of Vibrio

There has been an increase in reported outbreaks and cases of foodborne disease attributed to pathogenic Vibrio species. As a result, there have been several instances where the presence of pathogenic Vibrio spp. in seafood has led to a disruption in international trade. The number of Vibrio species being recognized as potential human pathogens is increasing. The food safety concerns associated with these microorganisms have led to the need for microbiological risk assessment to support risk management decision making for their control.

V. parahaemolyticus is considered to be part of the autochthonous microflora in the estuarine and coastal environments in tropical to temperate zones. Food safety concerns have been particularly evident with V. parahaemolyticus. There have been a series of pandemic outbreaks of V. parahaemolyticus foodborne illnesses due to the consumption of seafood. In addition, outbreaks of V. parahaemolyticus have occurred in regions of the world where it was previously unreported. The vast majority of strains isolated from patients with clinical illness produce a thermostable direct haemolysin (TDH) encoded by the tdh gene. Clinical strains may also produce a TDH-related haemolysin (TRH) encoded by the trh gene. It has therefore been considered that those strains that possess the tdh and/or trh genes and produce TDH and/or TRH should be considered those most likely to be pathogenic. V. vulnificus can occasionally cause mild gastroenteritis in healthy individuals following consumption of raw bivalve molluscs. It can cause primary septicaemia in individuals with chronic pre-existing conditions, especially liver disease or alcoholism, diabetes, haemochromatosis and HIV/AIDS. This can be a serious, often fatal, disease with one of the highest fatality rates of any known foodborne bacterial pathogen.

The 41st Session of the Codex Committee on Food Hygiene (CCFH) requested FAO/WHO to convene an expert meeting to address a number of issues relating to V. parahaemolyticus and V. vulnificus including:

  • conduct validation of the predictive risk models developed by the United States of America based on FAO/WHO risk assessments, with a view to constructing more applicable models for wider use among member countries, including adjustments for strain virulence variations and ecological factors;
  • review the available information on testing methodology and recommend microbiological methods for Vibrio spp. used to monitor the levels of pathogenic Vibrio spp. in seafood and/or water; and,
  • conduct validation of growth rates and doubling times for V. parahaemolyticus and V. vulnificus in Crassostrea virginica (Eastern or American oyster) using strains isolated from different parts of the world and different bivalve molluscan species.

The requested expert meeting was held on 13-17 September 2010, and this report is the outcome of this meeting. Rather than undertaking a validation exercise, the meeting considered it more appropriate to undertake an evaluation of the existing risk calculators with a view to determining the context to which they are applicable and potential modifications that would need to be made to extend their application beyond that context. A simplified calculator tool could then be developed to answer other specific questions routinely. This would be dependent on the availability of the appropriate data and effort must be directed towards this.

The development of microbiological monitoring methods, particularly molecular methods for V. parahaemolyticus and V. vulnificus is evolving rapidly. This means the identification of any single method for the purposes of monitoring these pathogens is challenging and also of limited value as the method is likely to be surpassed within a few years. Therefore, rather than making any single recommendation, the meeting considered it more appropriate to indicate a few of the monitoring options available while the final decision on the method selected will depend to a great extent on the specific purpose of the monitoring activity, the cost, the speed with which results are required and the technical capacity of the laboratory.

The meeting considered that monitoring seawater for V. parahaemolyticus and V. vulnificus in bivalve growth and harvest areas has limited value in terms of predicting the presence of these pathogens in bivalves. A linear relationship between levels of the vibrios in seawater and bivalves was not found and whatever relationship does exist can vary between region, the Vibrio spp. etc. Also, the levels of Vibrio species of concern in seawater tend to be very low. This presents a further challenge as the method used would need to have an appropriate level of sensitivity for their detection. Nevertheless, this does not preclude the testing of seawater for these vibrios; for example, in certain situations testing can provide an understanding of the aquatic microflora in growing areas. Monitoring of seafood for these pathogenic vibrios was considered the most appropriate way to get insight into the xii levels of the pathogens in these commodities at the time of harvest. Monitoring on an ongoing basis could be expensive, so consideration could be given to undertaking a study over the course of a year and using this as a means to establish a relationship between total and pathogenic V. parahaemolyticus and V. vulnificus in the seafood and abiotic factors such as water temperature and salinity. Once such a relationship is established for the harvest area of interest measuring these abiotic factors may be a more cost-effective way of monitoring. The meeting undertook an evaluation exercise rather than attempting to validate the existing growth models. The experts considered the JEMRA growth model for V. vulnificus and the FDA growth model for V. parahaemolyticus were appropriate for estimating growth in the American oyster (Crassostrea virginica). The JEMRA growth model for V. vulnificus was appropriate for estimating growth in at least one other oyster species, Crassostrea ariakensis. The FDA model for V. parahaemolyticus was also appropriate for estimating growth in at least one other oyster species, Crassostrea gigas, but was not appropriate for predicting growth in the Sydney rock oyster (Saccostrea glomerata). There was some evidence that the V. parahaemolyticus models currently used over predict growth at higher temperatures (e.g. > 25 °C) in live oysters. This phenomenon requires further investigation. Growth model studies were primarily undertaken using natural populations of V. parahaemolyticus as these were considered to be the most representative. Data were limited and inconsistent with respect to the impact of the strain on growth rate although recent studies in live oysters suggest differences exist between populations possessing tdh/trh (pathogenic) versus total or non-pathogenic populations of V. parahaemolyticus. There was no data to evaluate the performance of the growth models in any other oyster species or other filter feeding shellfish or other seafood and as such its use in these products could not be supported. If the models are used there should be a clear understanding of the associated uncertainty. This indicated a data gap which needs to be addressed before the risk assessments could be expanded in a meaningful manner.

Risk assessment tools for vibrio parahaemolyticus and vibrio vulnificus associated with seafood, 2020

World Health Organization

https://apps.who.int/iris/bitstream/handle/10665/330867/9789240000186-eng.pdf?sequence=1&isAllowed=y

Raw is risky: Meghan Markle had to give up eating favourite food after marrying Harry

Australia has this weird love of everything royal – at least on the news.

If Harry farts, it’s reported; if one of the kids picks their nose, it’s reported.

And now, Meghan Markle, the Duchess of Sussex, has been told by Royal Butler Grant Harold, she will have to stop eating her most adored cuisine – seafood.

Mr Harold explained this is because the Royal Family don’t eat it due to food poisoning fears.

He told Express.co.uk: “It is a very sensible move to abandon having seafood when out and about on public duties.

“We don’t want a member of the Royal family having a serious reaction to food poisoning, especially if she is on an overseas tour.”

In 2013, Meghan revealed her “ideal food day” would consist of a “dinner of seafood and pasta” with a Negroni cap it all off.

But this isn’t the only fancy food off the table for the newest addition to the family.

The butler added: “As well as shellfish, it would also be quite appropriate for foods such as foie gras to be avoided.”

Prince Charles is said to have banned the delicacy from the palace in 2008 over animal rights concerns.

Eel smuggling ring busted in Spain

Who smuggles eels?

Baby eels, a traditional Spanish tapas. Gulas al ajillo

Maybe by friend Steve (right, not exactly as shown), but no one else I would know.

Chris Chase of Seafood Source reports that Europol and the Spanish Guardia Civil, in collaboration with Portuguese authorities, seized 350 kilograms of elvers that were about to be smuggled out of Spain during “Operation Elvers,” the three agencies announced on 6 April.  

Ten suspects were arrested – Spanish, Chinese, and Moroccan nationals – in connection with smuggling the eels. Authorities estimate the group has managed to smuggle a value of EUR 37 million (USD 45.5 million) worth of eels over the course of their operation. 

The European eel is subject to multiple EU regulations, including a blanket ban on all imports and exports and a global restriction on trade. In 2009, the species was listed on Appendix II of the Convention on International Trade in Endangered Species (CITES) of Wild Fauna and Flora. Once it became clear that those measures weren’t enough, a ‘zero quota’ ban on all shipments to third countries was put into place.

A video released by the Spanish Guardia Civil shows authorities busting down doors in a raid on the elver smuggling facilities. Rows of tanks filled with make-shift aquaculture equipment, EUR 40,000 (USD 49,000) in cash, and stacks of travel bags used to smuggle the elvers out of the country were all found inside. According to Europol,  a total of 364 travel bags were being prepared to be sent to China, and could have been able to carry more than five tons of eels. 

The video also shows the 350 kilograms of live elvers, being released back into their natural habitat.

Fancy food ain’t safe food: New York edition

One of New York’s most expensive restaurants is in some trouble with the Food and Drug Administration over its fresh fish.

John Tozzi of Bloomberg writes that Masa, which earned three Michelin stars for its $595 tasting menu (before drinks and tax), received a warning letter from the FDA dated Oct. 16 alleging violations of federal rules that govern seafood imports. “Your fresh trevally and fresh Katsuwonus pelamis (Katsuo), also known as skipjack tuna or bonito,” the agency wrote in a letter published online this week, “have been prepared, packed, or held under insanitary conditions whereby they may have been rendered injurious to health.”

“We take FDA regulations very seriously and, of course, food safety is always a priority. We are working closely with our purveyors in Japan to get this resolved quickly,” said Tina Clabbers, a representative for Masa, in an email.

While the the FDA doesn’t typically regulate individual restaurants, the agency has jurisdiction over seafood importers. Inspectors visited Masa on June 22, according to the letter, which redacted the name of the restaurant’s fish supplier.

The letter doesn’t specify the precise nature of the violation, and a spokesperson in the FDA’s New York district office was not available for comment.

Raw is risky: Ceviche source of V. cholera 01 in Minn

As we drove the five hours yesterday to Sawtell, NSW, for a week of (ice) hockey for Sorenne, and some R&R for me and Amy (mainly me), Amy was telling me about this one time, she went to Senegal (they speak French) in 2005, and the hosts offered her Tang but she didn’t want to drink it because she had been warned about the water.

Turns out there was an on-going cholera outbreak.

I was driving and thought, should I tell her that cholera is a member of the Vibrio genus?

I kept driving.

Today, while Sorenne is working it on the ice, I’m catching up and came across this report from friends at the Minnesota Department of Health (MDH) published by the U.S. Centers for Disease Control.

On August 20, 2016, the Minnesota Department of Health (MDH) was notified of a case of Vibrio cholerae infection. The isolate was identified as serogroup O1, serotype Inaba at MDH. CDC determined that the isolate was nontoxigenic. The patient was a previously healthy woman, aged 43 years, with history of gastric bypass surgery. On August 16, she experienced profuse watery diarrhea, vomiting, abdominal cramps, and headache. On August 18, she sought care and submitted the stool specimen that yielded the V. cholerae isolate. She reported no recent travel. However, she had consumed ceviche made with raw shrimp and raw oysters at restaurant A on August 14, 49 hours before illness onset. Her husband had a similar illness with a similar incubation period after eating the same foods at restaurant A.

On August 22, MDH sanitarians visited restaurant A and obtained tags and invoices for oyster and shrimp products; the oysters were a product of the United States, and the shrimp was a product of India. Sanitarians also gathered patron contact information and credit card receipts for August 12–14. Two additional patrons reported experiencing a gastrointestinal illness that met the case definition of three or more episodes of watery stool in a 24-hour period within 5 days of eating at restaurant A; one reported eating ceviche and oysters at restaurant A. Review of complaints to the MDH foodborne illness hotline revealed a previous complaint from two persons who reported experiencing watery diarrhea after eating raw shrimp ceviche (but no oysters) at restaurant A on August 2. These persons did not provide stool specimens, but their gastrointestinal illnesses met the case definition, resulting in a total of six cases, including one laboratory-confirmed case. No other V. cholerae O1 Inaba cases were reported in the United States during this outbreak.

The Minnesota Department of Agriculture facilitated sampling of shrimp at the distributor from the same lots served at restaurant A on August 14, and most likely during August 2–13, and sent them to the Food and Drug Administration for culture. Shrimp samples yielded V. cholerae non-O1, non-O139, but V. cholerae O1 was not isolated. In response to the outbreak results, restaurant A placed consumer warnings on their menus about the risks of consuming raw or undercooked food items and identified raw menu items for consumers. Restaurant A also focused on other actions that might facilitate reduction of V. cholerae, including appropriate freezing of food items, and allowing raw food items to soak in lime juice before being served, rather than serving the items immediately after adding lime juice (1,2).

V. cholera has over 150 serogroups and has been identified in a wide range of aquatic life, including seafood (3). Whereas multiple serogroups can cause vibriosis, only serogroups O1 and O139 that also contain the cholera toxin are classified as causes of cholera (4). Previous studies have documented the presence of nontoxigenic V. cholerae O1 from environmental and shrimp samples in India and Southeast Asia (5–7).

This outbreak of domestically acquired, nontoxigenic V. cholerae infections, likely from shrimp consumption, included the first V. cholerae O1 case identified in a nontraveler in Minnesota since active surveillance for Vibrio began in 1996. Since 1996, MDH has detected 26 V. cholerae infections, 21 (81%) of which were non-O1, non- O139, and five of which were O1. Among the four O1 type cases identified before the current outbreak, all patients had a recent travel history to Micronesia or India. This outbreak demonstrates the importance of investigating all seafood eaten by patients with vibriosis. In addition, investigators should include nontoxigenic V. cholerae as a possible etiology of domestic foodborne outbreaks, particularly when foods eaten include those from V. cholerae O1–endemic areas.

Notes from the field: Vibrio cholerae Serogroup O1, Serotype Inaba — Minnesota, August 2016

CDC MMWR

Victoria Hall, Carlota Medus, George Wahl, Alida Sorenson, Melanie Orth, Monica Santovenia, Erin Burdette, Kirk Smith

https://www.cdc.gov/mmwr/volumes/66/wr/mm6636a6.htm?s_cid=mm6636a6_e

 

Seafood safety, roses and writing

Chapman is a shitty writer.

How he got a staff member named Katrina Levine, who can write, is beyond my grasp.

But, I’m content to be amazed at the world, not think too much about it, and be grateful for the beauty in a rose or an MPH who can put a couple of sentences together.

Katrina (whom I’ve never met) writes:

I’ve never been one who likes attention, but I’ll admit that during the 15 minutes of fame that came with the publication of Evaluating Food Safety Messages in Popular Cookbooks in the British Food Journal, I got a little excited every time someone wanted to interview me. Terrified, but excited.

During the 2 week media buzz that followed the press release, I did approximately 6 interviews, one of which was for Consumer Reports. Unlike most of the interviews, which were focused on our row with Gwyneth Paltrow or how her cookbook could give you food poisoning, the nice journalist I spoke with wanted my professional opinion on how to choose and prepare seafood safely.

As I said before in an earlier barfblog post, the media attention from this paper gave us an opportunity to share what we know about safe food handling while people were listening. So when this journalist asked me to talk about seafood food safety, share I did – for about 45 minutes.

The messages I shared ranged from safe thawing methods, such as running raw seafood under cold running water, to determining doneness using a thermometer or opacity. Sari Hararr of Consumer Reports writes:

In a hurry? For safe seafood, thaw frozen fish and shellfish under cold running water in a sealed plastic bag, then cook it right afterward, says Katrina Levine, M.P.H., a registered dietitian and an extension associate in food safety and nutrition at North Carolina State University in Raleigh

For thicker fish such as a salmon steak, you can slip the thermometer into a side of the fillet, Levine says. But because it’s almost impossible to use a thermometer on shellfish or a delicate fillet of sole, the USDA notes that it’s also considered safe to cook fish until the flesh is opaque and separates or flakes easily with a fork. Cook crabs, lobster, and shrimp until the flesh is opaque and pearly; clams, mussels, and oysters until their shells open; and scallops until they are milky white or firm and opaque.

Although seafood does not need to reach an internal temperature as high as some foods like ground beef – 145°F compared to 160°F for ground beef and 165°F for poultry – it’s not any less risky. Outbreaks of norovirus and Vibrio have been linked to raw or undercooked seafood.

We know that using a thermometer to check internal temperatures is the best practice for knowing when food is done. Yet, people are even less likely to use a thermometer on fish than on meat or poultry, and cookbook recipes are also less likely to include safe endpoint temperatures for fish. While raw or undercooked seafood may be trendy (sushi and raw oyster lovers – you know who you are), getting foodborne illness isn’t.

Why I don’t eat raw oysters: Vibrio thrives by attacking the cell’s cytoskeleton

The leading cause of acute gastroenteritis linked to eating raw seafood disarms a key host defense system in a novel way: It paralyzes a cell’s skeleton, or cytoskeleton.

That finding, from UT Southwestern Medical Center, was reported today in PLoS Pathogens. Without a working cytoskeleton, infected cells are unable to produce defensive molecules called reactive oxygen species (ROS) that normally attack bacterial DNA, said Dr. Marcela de Souza Santos, lead author of the study and a postdoctoral researcher in the laboratory of senior author Dr. Kim Orth. Dr. Orth is a Professor of Molecular Biology and Biochemistry at UT Southwestern as well as an Investigator in the prestigious Howard Hughes Medical Institute.

“Vibrio parahaemolyticus bacteria deploy a needlelike apparatus called a Type III Secretion System (T3SS) that injects toxic bacterial proteins, known as effectors, into cells that line the intestine, resulting in severe gastroenteritis,” Dr. de Souza Santos said.

Usually V. parahaemolyticus causes only a few days of gastrointestinal distress in the form of vomiting or diarrhea. On rare occasions, however, particularly in people with chronic health conditions like diabetes or liver disease that compromise the immune system, the bacteria can escape from the gut and enter the bloodstream, causing life-threatening systemic infection.

Of the nearly 80 known Vibrio strains, only about a dozen infect humans. The Centers for Disease Control and Prevention (CDC) estimates Vibrio cause 80,000 illnesses and 100 deaths in the U.S. annually. Of those, an estimated 45,000 people are sickened by V. parahaemolyticus. Another Vibrio strain, V. vulnificus, can cause life-threatening infections in people with open wounds exposed to warm seawater. As with other Vibrio strains, people who are immunocompromised are at highest risk.

“Vibrio parahaemolyticus is the reason for the old saying that you shouldn’t eat oysters in months without an ‘r’ in them, meaning the summer months,” said Dr. Orth, holder of the Earl A. Forsythe Chair in Biomedical Science and a W.W. Caruth, Jr. Scholar in Biomedical Research. “With the warming of the oceans, the risk now starts earlier in the year and the bacteria’s geographical range is spreading.” The CDC’s fact sheet says that 80 percent of U.S. vibriosis infections occur between May and October.

The state of Alaska reported its first V. parahaemolyticus outbreak in July 2004. Another strain of Vibrio sickened more than 80 people exposed to contaminated seawater during a heatwave in Northern Europe in 2014. The first Vibrio strains were identified in the 18th century.

Until recently, it was believed that Vibrio bacteria remained outside cells, doing their damage by shooting effectors into cells. However, in 2012, the Orth laboratory identified a way that V. parahaemolyticus tricks random cells lining the gut into engulfing the bacterium and bringing it inside the cell. The current study indicates how the T3SS protein VopL aids V. parahaemolyticus infection by helping the pathogen secure a niche within the cell for bacterial replication.

It’s a good strategy for a bacterium to infect random cells only, Dr. Orth said. If a pathogen were to infect most of the host’s cells quickly – as is thought to occur with the Ebola virus – the pathogen might kill its host so fast that it could undermine its own survival, she said.

In a study published last month in Science Signaling, the Orth laboratory did something unprecedented: It followed V. parahaemolyticus infection over time – flash freezing samples every 15 minutes – to chart the pathogen’s effect on host signaling. That study identified 398 genes whose expressions were changed by Vibrio infection, said lead author and postdoctoral researcher Dr. Nicole De Nisco.

In the current study, the researchers found that one of V. parahaemolyticus’ many effectors – VopL – paralyzes the cytoskeleton through a novel mechanism. The cellular machinery, or complex, that makes the ROS sits on the cell surface, but the molecules that the cellular factory needs to assemble ROS are created inside the cell. A working, flexible cytoskeleton is necessary to move the molecules to the ROS factory, she explained.

To confirm their observation, the researchers created two V. parahaemolyticus strains, one able to make VopL and another not. Using confocal microscopy, they found that the Vibrio able to produce VopL inactivated the assembly of ROS by gathering the cytoskeleton into nonfunctional filaments. In contrast, the mutant bacterium unable to produce VopL was vulnerable to ROS attack.

This study identifies the virulence factor used by V. parahaemolyticus to suppress host ROS generation and also reveals an unprecedented mechanism used by a microbial pathogen to do so, said Dr. Orth.

“By hijacking the cytoskeleton, VopL prevents the cell from launching one of its major weapons, reactive oxygen species,” said Dr. Orth. “We hope our work will lead to a better understanding of host defense, which, in turn could lead to new ways to undermine the pathogens.”

 

$30,000 worth of seafood stolen from Australian restaurant

Canada’s got its maple syrup gang, Brisbane area has its seafood thiefs.

Clare Armstrong of the Courier Mail reports more than $30,000 worth of seafood including prawns, crabs, Moreton Bay bugs and oysters was stolen from an external freezer at the Belvedere Hotel, Woody Point at about 1.45am on Wednesday.

seafood-theft-brisbanePolice said CCTV showed the thieves broke the lock on the freezer before loading more than 30 boxes of seafood into a white ute and fleeing the scene.

Belvedere General Manager Andrew Cox said the company had scrambled to replace all the stock in time for Christmas but it “could have been a total disaster”.

“These low-life people obviously don’t have any Christmas spirit at all … we ordered the seafood back in October but because of their actions more than 600 people almost had their Christmas lunch ruined,” he said.

Mr Cox said the seafood had only been delivered hours before the robbery, which appeared to have been carefully planned.

 

Salmonella in seafood in Kochi

A survey carried out by a team of scientists of the Microbiology, Fermentation and Biotechnology Division of Central Institute of Fisheries Technology (CIFT) Kochi, found Salmonella in 29 per cent of seafood samples.

seafood-kochiDuring the screening process, the researchers collected as many as 150 fresh seafood samples including popular varieties like sardine, mackerel, prawns and crabs from the markets in and around Kochi.

The study was conducted by a team of scientists including S.S. Greeshma, M.M. Prasad, K.V. Lalitha, Toms C. Joseph, and V. Murugadas.

The presence of salmonella in seafood indicates contamination with human and animal excreta. Fishes and shellfish normally do not harbour micro-organisms like salmonella but can get contaminated with through the use of contaminated ice, water, containers and poor hygienic handling practices, explained Dr. Greeshma.

Samples were collected over a period of nine months. Once salmonella reaches soil and aquatic environments, it can survive there for long periods.

While cooking kills the micro-organism, there exists the risk of cross-contamination with other food items that are consumed raw when handled along with seafood contaminated with salmonella.

Humans who come into direct contact with salmonella-contaminated seafoods face health risk, she explained.

The study underscores the need to hygienic handling of fish in the markets, said C.N. Ravishankar, Director of the Institute in a communication.

The researchers are planning a source study to identify the routes and points of possible contamination of the fish.