Cause Of Foodborne Illness Research Articles

2589 Disseminated Salmonella Species-Induced Septic Shock: A Case Report

INTRODUCTION: Nontyphoidal Salmonellosis is the leading cause of foodborne illness in the U.S., causing approximately 1.4 million infections annually. Most cases of Salmonellosis are due to ingestion of contaminated food items such as eggs, dairy products, and meats. We present a case of septic arthritis presumably after an episode of gastroenteritis that disseminates into Salmonella bacteremia in a patient without any of the risk factors for Salmonella bacteremia. This case suggests that Salmonella bacteremia can occur not only in patients with common risk factors but also patients with no obvious risk factors. CASE DESCRIPTION/METHODS: 81-year-old African American male with past medical history of end stage renal disease, congestive heart failure, hypertension, myocardial infarction, and cerebrovascular accident presents to the ED with new onset left lower extremity pain in the posterior aspect of the knee after completing dialysis earlier in the day. He was later admitted to the hospital for concern of a septic joint. On admission, his temperature was 97.4 degrees F, heart rate was 86 beats per minute, respiratory rate was 16 breaths per minute, and blood pressure was 130/70 mmHg. Basic metabolic panel showed electrolyte disturbances including hypochloremia of 94 mEq/L, creatinine of 7.2 mg/dL, and low GFR for an African American male of 9. Complete blood count showed a hemoglobin level of 16.1 g/dL and normal leukocyte count of 5.89 TH/uL. Arthrocentesis was done three days in a row, which all initially grew gram negative rods that were later determined to be Salmonella species. The patient was becoming hypotensive and was transferred to the critical care unit and was started on pressor support. Blood cultures were drawn on the second day of admission for concern of systemic infection, grew Salmonella species. Patient was weaned off pressor support and was discharged from the hospital in stable condition. DISCUSSION: Salmonella is typically a bacteria species that colonize the gastrointestinal tract, there is a chance of bacteremia if Salmonella spreads from the intestines to the mesenteric lymph nodes and then to nearby organs or the bloodstream directly. In our patient with septic arthritis of the knee joint due to Salmonella, the bacteria must have traveled from the gastrointestinal system through the mesenteric lymph nodes into the bloodstream and then reaching the knee joint, where it colonized and caused infection. Early intervention with broad-spectrum antibiotics is key in preventing mortality.

Quantification and discovery of PCR inhibitors found in food matrices commonly associated with foodborne viruses

Human norovirus is the leading cause of foodborne illness globally. Detection and quantification of norovirus commonly involves the use of reverse transcriptase quantitative polymerase chain reaction (RT-qPCR); however, the presence of inhibitory compounds in foods limit detection and accurate quantification. Although some studies have been done on PCR inhibitors from foods, many of them are over a decade old and do not investigate inhibition in contemporary one-step RT-qPCR-based detection chemistries. The purpose of this work was to quantify the degree of inhibition that occurs from inhibitory compounds found in produce (pectin) and mollusks (hemocyanin, glycogen)—foods commonly associated with norovirus outbreaks. RT-qPCR reactions containing different amounts of genomic bacteriophage MS2 RNA, a norovirus surrogate, were spiked with different concentrations of pectin (0.0625%–0.25% w/V), glycogen (1.25%–10%), and hemocyanin (0.0625%–0.25%). Past research has implicated glycogen as an inhibitory compound in oysters; however, even high levels of glycogen (10%) had no significant effect (P > 0.05) on amplification. Conversely, both pectin and hemocyanin caused complete inhibition at 0.25%, with no significant inhibition observed at 0.0625% (P < 0.05). Hemocyanin is abundant in the hemolymph of mollusks and previously untested as a PCR inhibitor. This work demonstrates that pectin and hemocyanin should be considered when testing produce and mollusk samples with PCR-based methods.

A robust human norovirus replication model in zebrafish larvae.

Human noroviruses (HuNoVs) are the most common cause of foodborne illness, with a societal cost of $60 billion and 219,000 deaths/year. The lack of robust small animal models has significantly hindered the understanding of norovirus biology and the development of effective therapeutics. Here we report that HuNoV GI and GII replicate to high titers in zebrafish (Danio rerio) larvae; replication peaks at day 2 post infection and is detectable for at least 6 days. The virus (HuNoV GII.4) could be passaged from larva to larva two consecutive times. HuNoV is detected in cells of the hematopoietic lineage and the intestine, supporting the notion of a dual tropism. Antiviral treatment reduces HuNoV replication by >2 log10, showing that this model is suited for antiviral studies. Zebrafish larvae constitute a simple and robust replication model that will largely facilitate studies of HuNoV biology and the development of antiviral strategies.

Eugenol as an antimicrobial wash treatment reduces Campylobacter jejuni in postharvest poultry

AbstractThe efficacy of the natural plant‐derived compound, eugenol (EG), as an antimicrobial wash treatment to reduce Campylobacter jejuni in postharvest poultry was investigated. The antimicrobial efficacy of EG was studied as a suspension, emulsion, or nanoemulsion treatment (two trials each). In each trial, chicken skin samples were inoculated with C. jejuni (∼7.2 Log CFU/sample), washed with treatments (0, 0.125, 0.25, 0.5, 1, or 2% EG corresponds to 0, 7.61, 15.22, 30.45, 60.90, or 121.8 mM, respectively) for 1 min, drip dried for 2 min, and then processed at 0, 8, and 24 hr of refrigerated storage (n = 5 samples/treatment/time point). All doses of the EG suspension consistently reduced C. jejuni counts with the greatest reduction (&gt;2.0 Log CFU/sample) for the 2% dose when compared with controls (p &lt; .05). EG emulsions or nanoemulsions did not provide any additional reduction in C. jejuni when compared to EG suspension. Our results suggest that EG could be an effective postharvest intervention strategy for reducing C. jejuni contamination on poultry products.Practical ApplicationsCampylobacter jejuni, a leading cause of foodborne illness in humans, is strongly associated with the consumption of contaminated poultry products. Interventions reducing C. jejuni contamination in poultry would reduce the risk of subsequent human infections. In this study, the antimicrobial efficacy of eugenol was studied in three different delivery systems; suspension, emulsion, or nanoemulsion. Our results demonstrated that eugenol was effective in reducing C. jejuni counts on chicken skin and can be used as a potential strategy to reduce Campylobacter on poultry products.

Identification of Primary Antimicrobial Resistance Drivers in Agricultural Nontyphoidal Salmonella enterica Serovars by Using Machine Learning.

Nontyphoidal Salmonella (NTS) is a leading global cause of bacterial foodborne morbidity and mortality. Our ability to treat severe NTS infections has been impaired by increasing antimicrobial resistance (AMR). To understand and mitigate the global health crisis AMR represents, we need to link the observed resistance phenotypes with their underlying genomic mechanisms. Broiler chickens represent a key reservoir and vector for NTS infections, but isolates from this setting have been characterized in only very low numbers relative to clinical isolates. In this study, we sequenced and assembled 97 genomes encompassing 7 serotypes isolated from broiler chicken in farms in British Columbia between 2005 and 2008. Through application of machine learning (ML) models to predict the observed AMR phenotype from this genomic data, we were able to generate highly (0.92 to 0.99) precise logistic regression models using known AMR gene annotations as features for 7 antibiotics (amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftiofur, ceftriaxone, streptomycin, and tetracycline). Similarly, we also trained "reference-free" k-mer-based set-covering machine phenotypic prediction models (0.91 to 1.0 precision) for these antibiotics. By combining the inferred k-mers and logistic regression weights, we identified the primary drivers of AMR for the 7 studied antibiotics in these isolates. With our research representing one of the largest studies of a diverse set of NTS isolates from broiler chicken, we can thus confirm that the AmpC-like CMY-2 β-lactamase is a primary driver of β-lactam resistance and that the phosphotransferases APH(6)-Id and APH(3″-Ib) are the principal drivers of streptomycin resistance in this important ecosystem.IMPORTANCE Antimicrobial resistance (AMR) represents an existential threat to the function of modern medicine. Genomics and machine learning methods are being increasingly used to analyze and predict AMR. This type of surveillance is very important to try to reduce the impact of AMR. Machine learning models are typically trained using genomic data, but the aspects of the genomes that they use to make predictions are rarely analyzed. In this work, we showed how, by using different types of machine learning models and performing this analysis, it is possible to identify the key genes underlying AMR in nontyphoidal Salmonella (NTS). NTS is among the leading cause of foodborne illness globally; however, AMR in NTS has not been heavily studied within the food chain itself. Therefore, in this work we performed a broad-scale analysis of the AMR in NTS isolates from commercial chicken farms and identified some priority AMR genes for surveillance.

Spray-dried anti-Campylobacter bacteriophage CP30A powder suitable for global distribution without cold chain infrastructure.

Campylobacter jejuni is a leading cause of foodborne illness globally. In this study, a spray drying and packaging process was developed to produce a thermally-stable dry powder containing bacteriophages that retains biological activity against C. jejuni after long distance shipping at ambient temperature. Spray drying using a twin-fluid atomizer resulted in significantly less (p < 0.05) titer reduction than spray drying using a vibrating mesh nebulizer. The use of centrifugation and dilution of filtered bacteriophage lysate in the formulation step resulted in a significantly greater (p < 0.05) proportion of bacteriophages remaining active relative to use of no centrifugation and dilution. The spray-dried bacteriophage powder generated using leucine and trehalose as excipients was flowable, non-cohesive, and exhibited a high manufacturing yield. The powder retained its titer with no significant differences (p > 0.05) in biological activity after storage in suitable packaging for at least 3 weeks at room temperature and after ambient temperature shipping a total distance of approximately 19,800 km, including with a 38 °C temperature excursion. The bacteriophage powder therefore appears suitable for global distribution without the need for cold chain infrastructure.

A Bacteriophage Cocktail Eliminates Salmonella Typhimurium from the Human Colonic Microbiome while Preserving Cytokine Signaling and Preventing Attachment to and Invasion of Human Cells by Salmonella In Vitro

Nontyphoidal Salmonella strains continue to be a major cause of foodborne illness globally. One intriguing approach to reducing the risk of salmonellosis is the direct ingestion of phages targeting Salmonella to enhance natural gut resilience and provide protection during foodborne disease outbreaks. We evaluated the ability of a prophylactically administered bacteriophage cocktail, the foodborne outbreak pill (FOP) targeting Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella, to resolve a Salmonella infection in the Simulator of the Human Intestinal Microbial Ecosystem (SHIME), a simulated gut platform populated by the human intestinal microbiome of healthy donors. The FOP preparation eliminated Salmonella enterica serovar Typhimurium from the colon compartment of the SHIME platform but health-associated metabolites, such as short-chain fatty acids and lactate, remained stable or increased in a donor-dependent manner. In studies of human intestinal cells, pretreatment of Salmonella Typhimurium with the FOP cocktail preserved lipopolysaccharide-stimulated signaling in a Caco-2-THP-1 Transwell system and prevented destruction of the Caco-2 monolayer by Salmonella. Adhesion and invasion of intestinal epithelial cells by Salmonella-a critical factor in Salmonella pathogenesis-was blunted when the bacteria were incubated with the FOP preparation before addition to the monolayer. The FOP phage cocktail was effective for (i) eliminating Salmonella from a simulated human gut without disturbing the indigenous microbiota and (ii) reducing the risk of invasion by Salmonella into the intestinal epithelia. These results suggest that the FOP preparation may be of value for reducing the risk of salmonellosis in humans, e.g., during foodborne disease outbreaks.

Analysis of the capacity of Salmonella enterica Typhimurium to infect the human Placenta

IntroductionSalmonella species are gram-negative facultative intracellular bacteria that are common causes of foodborne illness in North America. Infections by Salmonella during pregnancy are a significant cause of fetal loss in domestic livestock, and fetal and maternal mortality in mice. Furthermore, Salmonella infection is associated with miscarriage, stillbirth and preterm birth in pregnant women. Despite these collective associations, the extent to which Salmonella can infect the human placenta has not been investigated. MethodsHuman placental villous explants from several gestational ages were exposed to Salmonella enterica serovar Typhimurium (STm) ex vivo. Infection was assessed by colony forming unit assay and whole mount immunofluorescence (WMIF). ResultsViable bacteria were recovered from placental villous explants of all gestational ages tested, but the bacterial burden was highest in 1st trimester explants. Bacterial numbers did not change appreciably with time post-infection in explants from any gestational age examined, suggesting that STm does not proliferate in placental villi. Exposure of villous explants to STm strains defective for the type III secretion systems revealed that Salmonella pathogenicity island 1 is essential for optimal invasion. In contrast to placental explants, STm infected and proliferated within villous cytotrophoblast cells isolated from term placentas. WMIF demonstrated that STm was restricted primarily to the syncytiotrophoblast layer in infected placentas. DiscussionOur study demonstrates that STm can invade into the syncytiotrophoblast but does not subsequently proliferate. Thus, the syncytiotrophoblast may function as a barrier to STm infection of the fetus.

Corrigendum: Prevalence and Serotype Diversity of Salmonella in Apparently Healthy Cattle: Systematic Review and Meta-Analysis of Published Studies, 2000-2017.

[This corrects the article DOI: 10.3389/fvets.2019.00102.].

Detection and quantification of Salmonella spp. in poultry slaughterhouses of southern Brazil.

Salmonella is a major cause of foodborne illness throughout the world. The use of quantitative techniques is important for assessing the risk and determining the capacity of each step of the slaughtering process to decrease or increase bacterial contamination. We aimed to detect and to quantify the presence of Salmonella in Brazilian processing plants by real-time quantitative polymerase chain reaction (qPCR). A total of 139 poultry slaughterhouses samples were collected in order to detect to and quantify Salmonella by qPCR. Almost all collection points (3/18), except water from pre-chiller tank, carcasses after pre-chiller, and carcasses frozen at -12ºC for 60 days, and 49% (68/139) of samples were positive for Salmonella. Quantification means varied equally among all of the tested sources, and we could not establish any pattern of variation. A large proportion (52.6%) of cloacal swabs was Salmonella-positive. Also, contamination in transport cages was increased after the cleaning process, indicating that the process was ineffective. The overall prevalence in samples obtained during the slaughtering process was 48.9%, and on the whole rinsed carcasses, this proportion was 50%. The detection of Salmonella in frozen carcasses, even after long periods of storage, indicates that the carcasses are a potential source of infection for consumers. We found that contamination levels remain similar throughout the slaughtering. qPCR proved to be an efficient method for the detection of Salmonella.

Infection-Induced Intestinal Dysbiosis Is Mediated by Macrophage Activation and Nitrate Production.

Oral infection of C57BL/6J mice with Toxoplasma gondii results in a marked bacterial dysbiosis and the development of severe pathology in the distal small intestine that is dependent on CD4+ T cells and interferon gamma (IFN-γ). This dysbiosis and bacterial translocation contribute to the development of ileal pathology, but the factors that support the bloom of bacterial pathobionts are unclear. The use of microbial community profiling and shotgun metagenomics revealed that Toxoplasma infection induces a dysbiosis dominated by Enterobacteriaceae and an increased potential for nitrate respiration. In vivo experiments using bacterial metabolic mutants revealed that during this infection, host-derived nitrate supports the expansion of Enterobacteriaceae in the ileum via nitrate respiration. Additional experiments with infected mice indicate that the IFN-γ/STAT1/iNOS axis, while essential for parasite control, also supplies a pool of nitrate that serves as a source for anaerobic respiration and supports overgrowth of Enterobacteriaceae Together, these data reveal a trade-off in intestinal immunity after oral infection of C57BL/6J mice with T. gondii, in which inducible nitric oxide synthase (iNOS) is required for parasite control, while this host enzyme is responsible for specific modification of the composition of the microbiome that contributes to pathology.IMPORTANCEToxoplasma gondii is a protozoan parasite and a leading cause of foodborne illness. Infection is initiated when the parasite invades the intestinal epithelium, and in many host species, this leads to intense inflammation and a dramatic disruption of the normal microbial ecosystem that resides in the healthy gut (the so-called microbiome). One characteristic change in the microbiome during infection with Toxoplasma-as well as numerous other pathogens-is the overgrowth of Escherichia coli or similar bacteria and a breakdown of commensal containment leading to seeding of peripheral organs with gut bacteria and subsequent sepsis. Our findings provide one clear explanation for how this process is regulated, thereby improving our understanding of the relationship between parasite infection, inflammation, and disease. Furthermore, our results could serve as the basis for the development of novel therapeutics to reduce the potential for harmful bacteria to bloom in the gut during infection.

Bacteriological quality and the prevalence of Salmonella spp. and E. coli O157:H7 in ready‐to‐eat foods from Barbados, WI

AbstractThe bacteriological quality and safety of ready‐to‐eat (RTE) foods in Barbados were assessed in two separate studies conducted between 2014 and 2016. In Study 1, 206 food samples were processed for Salmonella spp. by conventional bacteriological methods. Polymerase chain reaction (PCR) and serotyping were used for confirmation. In Study 2, 120 food samples were processed for the total aerobic plate count (TAPC), coliform count, and E. coli count using conventional bacteriological methods. After a 24 hr pre‐enrichment, the food samples were screened for Salmonella spp. and E. coli O157:H7 by PCR. To validate the PCR screening method for use after pre‐enrichment, the detection limit was investigated in cooked chicken samples spiked with 10‐fold serial dilutions of an overnight culture of Salmonella Enteritidis. In Study 1, the prevalence of Salmonella Enteritidis was 1.5% (3/206). In Study 2, the prevalence of E. coli was 1.7%, and unsatisfactory TAPC (12.5%) and coliform counts (4.2%) were documented. The PCR screen detected DNA extracted from homogenates with as low as 6 CFU/mL, after a 24 hr pre‐enrichment. However, all samples screened negative (0.0%) for Salmonella spp. and E. coli O157:H7. Compared with other developing countries, the prevalence of pathogens in RTE foods in Barbados is low.Practical applicationsSalmonella and E.coli are major causes of food borne illness globally and antibiotic resistance among these bacteria have presented increasing challenges for clinicians. Studies demonstrate that bacterial contamination in ready‐to‐eat (RTE) foods have varied among developed and developing nations. While there are several published reports on the bacterial contamination of RTE foods from the developing Caribbean region, none have originated from Barbados. This study is the first to report a low prevalence of Salmonella, E. coli and other microbial contaminants in RTE foods sold in popular tourist districts in Barbados. This information can be applied to food safety considerations for public health and the tourism industry.

High Prevalence of Fluoroquinolone-Resistant Campylobacter Bacteria in Sheep and Increased Campylobacter Counts in the Bile and Gallbladders of Sheep Medicated with Tetracycline in Feed.

Campylobacter is a major foodborne pathogen in humans and a significant cause of abortion in sheep. Although ruminants are increasingly recognized as important reservoirs for Campylobacter species, limited information is available about the molecular epidemiology and antimicrobial resistance (AMR) profiles of sheep Campylobacter Here, we describe a two-trial study that examined Campylobacter profiles in sheep and determined whether in-feed tetracycline (TET) influenced the distribution and AMR profiles of Campylobacter Each trial involved 80 commercial sheep naturally infected with Campylobacter: 40 of these sheep were medicated with tetracycline in feed, while the other 40 received feed without antibiotics. Fecal and bile samples were collected for the isolation of Campylobacter The bacterial isolates were analyzed for antimicrobial susceptibility and genotypes. The results revealed that 87.0% and 61.3% of the fecal and bile samples were positive for Campylobacter (Campylobacter jejuni and Campylobacter coli), with no significant differences between the medicated and nonmedicated groups. All but one of the tested Campylobacter isolates were resistant to tetracycline. Although fluoroquinolone (FQ) resistance remained low in C. jejuni (1.7%), 95.0% of the C. coli isolates were resistant to FQ. Genotyping revealed that C. jejuni sequence type 2862 (ST2862) and C. coli ST902 were the predominant genotypes in the sheep. Feed medication with tetracycline did not affect the overall prevalence, species distribution, and AMR profiles of Campylobacter, but it did increase the total Campylobacter counts in bile and gallbladder. These findings identify predominant Campylobacter clones, reveal the high prevalence of FQ-resistant C. coli, and provide new insights into the epidemiology of Campylobacter in sheep.IMPORTANCECampylobacter is a major cause of foodborne illness in humans, and antibiotic-resistant Campylobacter is considered a serious threat to public health in the United States and worldwide. As a foodborne pathogen, Campylobacter commonly exists in the intestinal tract of ruminant animals, such as sheep and cattle. Results from this study reveal the predominant genotypes and high prevalence of tetracycline (TET) and fluoroquinolone (FQ) resistance in sheep Campylobacter The finding on fluoroquinolone resistance in sheep Campylobacter is unexpected, as this class of antibiotics is not used for sheep in the United States, and it may suggest the transmission of fluoroquinolone-resistant Campylobacter from cattle to sheep. Additionally, the results demonstrate that in-feed medication with tetracycline increases Campylobacter counts in gallbladders, suggesting that the antibiotic promotes Campylobacter colonization of the gallbladder. These findings provide new information on Campylobacter epidemiology in sheep, which may be useful for curbing the spread of antibiotic-resistant Campylobacter in animal reservoirs.

Influence of prior pH and thermal stresses on thermal tolerance of foodborne pathogens.

Improper food processing is one of the major causes of foodborne illness. Accurate prediction of the thermal destruction rate of foodborne pathogens is therefore vital to ensure proper processing and food safety. When bacteria are subjected to pH and thermal stresses during growth, sublethal stresses can occur that may lead to differences in their subsequent tolerance to thermal treatment. As a preliminary study to test this concept, the current study evaluated the effect of prior pH and thermal stresses on thermal tolerance of Salmonella and Staphylococcus using a tryptic soy broth supplemented with yeast extract. Bacteria incubated at three pH values (6.0, 7.4, and 9.0) and four temperatures (15, 25, 35, and 45°C) for 24 hr were subjected to thermal treatments at 55, 60, and 65°C. At the end of each treatment time, bacterial suspensions were surface‐plated on standard method agar for quantification of bacterial survival and further calculation of the thermal death decimal reduction time (D‐value) and thermal destruction temperature (z‐value). The effect of pH stress alone during the incubation on the thermal tolerance of both bacteria was generally insignificant. An increasing pattern of D‐value was observed with the increment of thermal stress (incubation temperature). The bacteria incubated at 35°C required the highest z‐value to reduce the 90% in D‐values. Staphylococcus mostly displayed higher tolerance to thermal treatment than Salmonella. Although further research is needed to validate the current findings on food matrices, findings in this study clearly affirm that adaptation of bacteria to certain stresses may reduce the effectiveness of preservation procedures applied during later stage of food processing and storage.

Differential phenotypes and localization of CD8 T cell responses to acute and chronic viral infection

Abstract Norovirus represents the major viral source of gastroenteritis worldwide and the leading cause of foodborne illness in North America. Most infections are acute, symptomatic, and rapidly cleared but some cases persist asymptomatically or induce post-infectious irritable bowel syndrome. Despite the global economic burden of these infections no vaccine to prevent disease exists. Using immune correlates of acute vs chronic infection in mouse models following infection with related strains of murine norovirus, MNV-CW3 and MNV-CR6 respectively, this research interrogates the mechanisms underlying strain-specific differential antiviral CD8 T cell responses. The phenotype and quantity of MNV specific CD8 T cells are analyzed by flow cytometry. Since MNV-CW3 and -CR6 replication is higher in the small and large intestine, respectively, immunofluorescent microscopy is used to determine whether CD8 T cells are preferentially recruited to either tissue. Combining these complementary techniques provides novel insight into mechanisms governing intestinal antiviral T cell responses. Preliminary data shows activated MNV-specific CD8 T cells first accumulate in the MLN, suggesting this is the site of immune activation following oral infection with either virus. However, the magnitude and kinetics of T cell activation are reduced in CR6-infected mice compared to CW3-infected mice. This data suggests that these highly related viral strains induce activation of distinct populations of, or pathways in, APC populations with long-lasting effects on the outcome of infection. These results may have broad impacts on our understanding of how non-latent, chronic viral infections persist within a host.

Review of Biological and Chemical Health Risks Associated with Pork Consumption in Vietnam: Major Pathogens and Hazards Identified in Southeast Asia

Foodborne illness is a difficult public health burden to measure, with accurate incidence data usually evading disease surveillance systems. Yet, the global scope of foodborne disease and its impacts on socioeconomic development make it an important health risk to address, particularly in low- and middle-income countries. In Vietnam, rapid development has seen large-scale commercial operations rise to coexist amongst traditional value chains in the food landscape, most of which operates outside of a domestic food safety network. Rapid socioeconomic development has also seen an increase in meat consumption, with pork being the most consumed meat product nationally. Expanding pork value chains, and the increasing diversity of actors within them, facilitates the growth and propagation of hazards which are passed onto Vietnamese consumers. In order to guide illness prevention and governance efforts, this review was conducted to examine health risks associated with pork consumption in Vietnam. Synthesis of the available literature provided evidence that Salmonella spp. bacteria are a major cause of foodborne illness from Vietnamese pork products. However, contaminants of global concern, including Salmonella spp. and Trichinella spiralis, occur alongside those considered neglected tropical diseases, such as Taenia solium. Infections and complications associated with ingestion of Streptococcus suis bacteria are also an issue, with Streptococcus suis infections usually limited to occupational infections amongst meat handlers in modernised value chains. A risk factor underscoring transmission of Trichinella spiralis, Taenia solium, and Streptococcus suis in Vietnam that emerges from the literature is the consumption of dishes containing raw or undercooked pork. Available data indicates that infections associated with raw pork consumption disproportionately affect men and people in regional mountainous areas of northwest Vietnam, where many of Vietnam’s ethnic minority communities reside. In addition, epidemiological data from recorded disease outbreaks that result from raw pork consumption demonstrate that these outbreaks usually follow major sociocultural events such as weddings, funerals, and Lunar New Year celebrations. Potential health impacts resulting from residues of antibiotics and heavy metals are also cause for concern, though the direct links between chemical contaminants in food and the development of disease are difficult to conclusively deduce.

Potential Therapeutic Effects of Mepacrine against Clostridium perfringens Enterotoxin in a Mouse Model of Enterotoxemia.

Clostridium perfringens enterotoxin (CPE) is a pore-forming toxin that causes the symptoms of common bacterial food poisoning and several non-foodborne human gastrointestinal diseases, including antibiotic-associated diarrhea and sporadic diarrhea. In some cases, CPE-mediated disease can be very severe or fatal due to the involvement of enterotoxemia. Therefore, the development of potential therapeutics against CPE action during enterotoxemia is warranted. Mepacrine, an acridine derivative drug with broad-spectrum effects on pores and channels in mammalian membranes, has been used to treat protozoal intestinal infections in human patients. A previous study showed that the presence of mepacrine inhibits CPE-induced pore formation and activity in enterocyte-like Caco-2 cells, reducing the cytotoxicity caused by this toxin in vitro Whether mepacrine is similarly protective against CPE action in vivo has not been tested. When the current study evaluated whether mepacrine protects against CPE-induced death and intestinal damage using a murine ligated intestinal loop model, mepacrine protected mice from the enterotoxemic lethality caused by CPE. This protection was accompanied by a reduction in the severity of intestinal lesions induced by the toxin. Mepacrine did not reduce CPE pore formation in the intestine but inhibited absorption of the toxin into the blood of some mice. Protection from enterotoxemic death correlated with the ability of this drug to reduce CPE-induced hyperpotassemia. These in vivo findings, coupled with previous in vitro studies, support mepacrine as a potential therapeutic against CPE-mediated enterotoxemic disease.

Population structure and genetic diversity of Vibrio parahaemolyticus from a coastal area of China based on a multi-locus sequence typing (MLST) scheme.

The Gram-negative marine bacterium Vibrio parahaemolyticus has been identified as a major cause of bacterial food poisoning in China. Here, the population structure and genetic diversity of V. parahaemolyticus from Weihai, a coastal city in China, was studied by the multi-locus sequence typing (MLST) method. In this survey, we isolated 40 strains including environmental and clinical samples of patients with acute gastroenteritis or diarrhea; isolates from other countries were also included for comparison. DnaSP Version5, START V2, eBURST version3 and Mega 6 were used to analyse the data. We found that ST3 and ST332 were the most prevalent clones and that they were closely associated with acute diarrhoeal diseases. These STs showed a low dN/dS ratio and significant linkage disequilibrium. All isolates were divided into four clonal complexes, six groups and nine singletons, showing a high degree of genetic diversity. 18 STs, mostly from environmental isolates, were recognised by the MLST analysis for the first time. In conclusion, ST3 and ST332 were the epidemic STs in the coastal area. ST332 might be a region-specific ST, which needs to be confirmed by further analysis. Thus, the long-term monitoring of V. parahaemolyticus plays an important role in preventing and controlling the transmission between environment and people in Weihai.

Estimated Annual Deaths, Hospitalizations, and Emergency Department and Physician Office Visits from Foodborne Illness in Ontario.

Public Health Ontario is working to estimate the burden of disease from environmental hazards in Ontario, Canada. As part of this effort, we estimated deaths and health care utilization resulting from exposure to pathogens and toxic substances in food. We applied fractions for the proportion of illness attributable to foodborne transmission to the annual (2008–2012) counts of deaths, hospitalizations, emergency department (ED) visits, and physician office visits for 15 diseases (13 pathogen-specific diseases and 2 nonspecific syndromes) captured by administrative health data. Nonspecific gastroenteritis (causative agent unknown) was the dominant disease, accounting for 98% of ED visits, 94% of hospitalizations, and 88% of deaths annually attributed to the 15 diseases. We estimated that foodborne nonspecific gastroenteritis results in ∼137,000 physician office visits (1000/100,000 population), 40,000 ED visits (310/100,000), 6200 hospitalizations (47/100,000), and 59 deaths (0.45/100,000) in Ontario per year (mean estimates). Our results indicate that pathogen-specific approaches to foodborne disease surveillance can substantially underestimate the deaths and illness resulting from exposure to foodborne pathogens and other causes of foodborne illness.

Prevalence and antimicrobial resistance of Campylobacterfrom antibiotic-free broilers during organic and conventional processing

Campylobacter is one of the leading cause of foodborne illness in the US and worldwide, especially linked to poultry and poultry products. In recent years, the increasing popularity of organic chicken products and chickens raised without antibiotics (RWA) has resulted in more companies adopting organic and antibiotic-free production and processing methods; however, it is not evident what effect these practices have on pathogens such as Campylobacter. The purpose of this study was to determine the effects of RWA and organic methods on the prevalence and antimicrobial resistance (AMR) of Campylobacter. Samples were collected from a processing facility that used organic and conventional methods to process RWA broilers. Samples included fecal grab samples from incoming birds, carcass rinses at important steps throughout processing, and environmental samples including equipment swabs, water samples, and air samples. Samples were analyzed for prevalence of Campylobacter by enrichment, and populations of presumptive Campylobacter were quantified. Isolates collected in this study were analyzed for AMR according to the National Antimicrobial Resistance Monitoring System (NARMS) protocol. Results showed that organic birds had a lower prevalence (P < 0.05) of Campylobacter and lower populations of presumptive Campylobacter during early processing steps, but no differences (P > 0.05) between organic and conventional birds were seen post-chill, with the exception of a lower prevalence in post-water-chill organic birds. These observations show that organic methods can be associated with lower initial Campylobacter levels than conventional methods, although appropriate processing interventions result in similar Campylobacter populations post-chill, regardless of processing method. Prevalence of AMR Campylobacter in chickens at slaughter suggest that raising birds without the use of antimicrobials may not be effective in reducing the incidence of AMR Campylobacter in chicken.