Risk factors for Salmonella Enteritidis and Typhimurium (DT104 and non-DT104) infections in The Netherlands: predominant roles for raw eggs in Enteritidis and sandboxes in Typhimurium infections

A Population-Based Study on the Incidence, Risk Factors, and Outcome of Salmonella Bloodstream Infections in South Sweden 2012-2022

INTRODUCTION

Invasive infections caused by Salmonella are a significant global health concern. This population-based study aimed to comprehensively analyze invasive Salmonella infections in South Sweden, focusing on incidence, clinical presentation, risk factors, and outcomes.

METHODS

This population-based observational cohort study, conducted from 2012 to 2022, included all patients with Salmonella bloodstream infections (BSI) in the Skåne region, South Sweden. A control group consisted of patients with positive stool cultures/PCR for Salmonella but without BSI. Data were collected following a predefined study protocol from medical records. Standardized statistical analyses assessed patient characteristics, clinical presentation, and outcomes.

RESULTS

Between 2012 and 2022, 149 patients with SBSI were identified, with the majority having non-typhoidal Salmonella (NTS) infections (95%). A declining trend in the incidence of SBSI was observed, with the highest incidence in 2012 (1.5 per 100,000 person-years) and the lowest in 2020 (0.3 per 100,000 person-years). Patients with BSI were more likely to be older, have comorbidities, be immunosuppressed, and use proton pump inhibitors (PPIs). Additionally, patients with BSI presented with fewer gastrointestinal symptoms, had a higher respiratory rate, lower saturation, and higher SOFA scores, suggesting a more septic presentation. Patients with SBSI had significantly longer hospital stays and higher 30-day, 90-day, 180-day, and 365-day mortality rates compared to the control group.

CONCLUSION

Invasive Salmonella infections are rare in South Sweden. In a cohort of enteric and invasive Salmonella infection, the absence of classic gastroenteritis symptoms increases the risk of Salmonella bloodstream infection. This study highlights the importance of distinguishing between clinical presentations to guide appropriate treatment when Salmonella infection is suspected. The declining trend in incidence, particularly associated with international travel, necessitates further investigation to understand contributing factors.

Antibiotic-induced collateral damage to the microbiota and associated infections

Antibiotics have transformed medicine, saving millions of lives since they were first used to treat a bacterial infection. However, antibiotics administered to target a specific pathogen can also cause collateral damage to the patient's resident microbial population. These drugs can suppress the growth of commensal species which provide protection against colonization by foreign pathogens, leading to an increased risk of subsequent infection. At the same time, a patient's microbiota can harbour potential pathogens and, hence, be a source of infection. Antibiotic-induced selection pressure can cause overgrowth of resistant pathogens pre-existing in the patient's microbiota, leading to hard-to-treat superinfections. In this Review, we explore our current understanding of how antibiotic therapy can facilitate subsequent infections due to both loss of colonization resistance and overgrowth of resistant microorganisms, and how these processes are often interlinked. We discuss both well-known and currently overlooked examples of antibiotic-associated infections at various body sites from various pathogens. Finally, we describe ongoing and new strategies to overcome the collateral damage caused by antibiotics and to limit the risk of antibiotic-associated infections.

Potential long consequences from internal and external ecology: loss of gut microbiota antifragility in children from an industrialized population compared with an indigenous rural lifestyle

Human health is strongly mediated by the gut microbiota ecosystem, which, in turn, depends not only on its state but also on its dynamics and how it responds to perturbations. Healthy microbiota ecosystems tend to be in criticality and antifragile dynamics corresponding to a maximum complexity configuration, which may be assessed with information and network theory analysis. Under this complex system perspective, we used a new analysis of published data to show that a children's population with an industrialized urban lifestyle from Mexico City exhibits informational and network characteristics similar to parasitized children from a rural indigenous population in the remote mountainous region of Guerrero, México. We propose then, that in this critical age for gut microbiota maturation, the industrialized urban lifestyle could be thought of as an external perturbation to the gut microbiota ecosystem, and we show that it produces a similar loss in criticality/antifragility as the one observed by internal perturbation due to parasitosis by the helminth A. lumbricoides. Finally, several general complexity-based guidelines to prevent or restore gut ecosystem antifragility are discussed.

Proton pump inhibitor-induced gut dysbiosis and immunomodulation: current knowledge and potential restoration by probiotics

Proton pump inhibitors (PPIs) are the most commonly prescribed drugs for the treatment of non-erosive reflux disease (NERD), ulcers associated with non-steroidal anti-inflammatory drugs (NSAIDs), esophagitis, peptic ulcer disease (PUD), Zollinger-Ellison syndrome (ZES), gastroesophageal reflux disease (GERD), non-ulcer dyspepsia, and Helicobacter pylori eradication therapy. The drugs have the effect of inhibiting acid production in the stomach. According to research, PPIs can affect the composition of gut microbiota and modulate the immune response. Recently, there has been a problem with the over-prescription of such drugs. Although PPIs do not have many side effects, their long-term use can contribute to small intestinal bacterial overgrowth (SIBO) or C. difficile and other intestinal infections. Probiotic supplementation during PPIs therapy may provide some hope in the reduction of emerging therapy side effects. This review aims to present the most important effects of long-term PPI use and provides critical insights into the role of probiotic intervention in PPI therapy.

Mouse models for bacterial enteropathogen infections: insights into the role of colonization resistance

Globally, enteropathogenic bacteria are a major cause of morbidity and mortality.1-3 Campylobacter, Salmonella, Shiga-toxin-producing Escherichia coli, and Listeria are among the top five most commonly reported zoonotic pathogens in the European Union.4 However, not all individuals naturally exposed to enteropathogens go on to develop disease. This protection is attributable to colonization resistance (CR) conferred by the gut microbiota, as well as an array of physical, chemical, and immunological barriers that limit infection. Despite their importance for human health, a detailed understanding of gastrointestinal barriers to infection is lacking, and further research is required to investigate the mechanisms that underpin inter-individual differences in resistance to gastrointestinal infection. Here, we discuss the current mouse models available to study infections by non-typhoidal Salmonella strains, Citrobacter rodentium (as a model for enteropathogenic and enterohemorrhagic E. coli), Listeria monocytogenes, and Campylobacter jejuni. Clostridioides difficile is included as another important cause of enteric disease in which resistance is dependent upon CR. We outline which parameters of human infection are recapitulated in these mouse models, including the impact of CR, disease pathology, disease progression, and mucosal immune response. This will showcase common virulence strategies, highlight mechanistic differences, and help researchers from microbiology, infectiology, microbiome research, and mucosal immunology to select the optimal mouse model.

Changing epidemiology of Salmonella Enteritidis human infections in the Netherlands and Belgium, 2006 to 2019: a registry-based population study

BackgroundSalmonellosis remains the second most common zoonosis in the European Union despite a long-term decreasing trend. However, this trend has been reported to have stagnated in recent years, particularly for Salmonella enterica serotype Enteritidis (SE).AimTo describe temporal changes in the incidence of SE human infections, and in its associated factors between 2006 and 2019. In addition, we aim to determine which factors influenced the stagnated trend seen in recent years.MethodsData on culture-confirmed SE human infections from national surveillance registries in the Netherlands and Belgium between 2006 and 2019 were analysed using multivariable negative-binomial regression models with restricted cubic splines.ResultsSE incidence was significantly higher in summer and autumn than winter, in persons aged 0-4 years and 5-14 years than in persons ≥ 60 years, and increased with increasing proportions of travel-related and resistant SE infections. SE incidence decreased significantly in both countries until 2015, followed by an increasing trend, which was particularly pronounced in the Netherlands. Potential SE outbreaks in both countries and invasive infections in the Netherlands also increased after 2015.ConclusionThe increase in potential outbreaks and invasive infections since 2015 may partially explain the observed reversal of the decreasing trend. While these results provide insights into the possible causes of this trend reversal, attention should also be given to factors known to influence SE epidemiology at primary (animal) production and pathogen genomic levels.

A statistical modelling approach for source attribution meta-analysis of sporadic infection with foodborne pathogens

Numerous source attribution studies for foodborne pathogens based on epidemiological and microbiological methods are available. These studies provide empirical data for modelling frameworks that synthetize the quantitative evidence at our disposal and reduce reliance on expert elicitations. Here, we develop a statistical model within a Bayesian estimation framework to integrate attribution estimates from expert elicitations with estimates from microbial subtyping and case-control studies for sporadic infections with four major bacterial zoonotic pathogens in the Netherlands (Campylobacter, Salmonella, Shiga toxin-producing E. coli [STEC] O157 and Listeria). For each pathogen, we pooled the published fractions of human cases attributable to each animal reservoir from the microbial subtyping studies, accounting for the uncertainty arising from the different typing methods, attribution models, and year(s) of data collection. We then combined the population attributable fractions (PAFs) from the case-control studies according to five transmission pathways (domestic food, environment, direct animal contact, human-human transmission and travel) and 11 groups within the foodborne pathway (beef/lamb, pork, poultry meat, eggs, dairy, fish/shellfish, fruit/vegetables, beverages, grains, composite foods and food handlers/vermin). The attribution estimates were biologically plausible, allowing the human cases to be attributed in several ways according to reservoirs, transmission pathways and food groups. All pathogens were predominantly foodborne, with Campylobacter being mostly attributable to the chicken reservoir, Salmonella to pigs (albeit closely followed by layers), and Listeria and STEC O157 to cattle. Food-wise, the attributions reflected those at the reservoir level in terms of ranking. We provided a modelling solution to reach consensus attribution estimates reflecting the empirical evidence in the literature that is particularly useful for policy-making and is extensible to other pathogens and domains.

Dietary Acrylamide Intake Alters Gut Microbiota in Mice and Increases Its Susceptibility to Salmonella Typhimurium Infection

Acrylamide (AA) has been extensively examined for its potential toxicological effects on humans and animals, but its impacts on gut microbiota and effects on hosts’ susceptibility to enteric infection remain elusive. The present study was designed to evaluate the effect of AA on gut microbiota of mice and susceptibility of mice to S. Typhimurium infection. After four weeks’ intervention, mice fed with AA exhibited significantly decreased body weight. Meanwhile, 16S rRNA gene sequencing showed reduced relative abundance of Firmicutes and increased abundance of Bacteroidetes in AA-treated mice prior to infection. In addition, we observed high relative abundance of Burkholderiales and Erysipelotrichales, more specifically the genus Sutterella and Allobaculum, respectively, in AA-treated mice before infection. Subsequently, the mice were orally infected with S. Typhimurium. The histological changes, systemic dissemination of S. Typhimurium, and inflammatory responses were examined. Compared to mice fed with normal diet, mice fed AA exhibited higher level of bacterial counts in liver, spleen, and ileum, which was consistent with exacerbated tissue damage determined by histological analyses. In addition, higher expression of pro-inflammaroty cytokines, p-IκBα, and p-P65 and lower mRNA expressions of mucin2, occludin, zo-1, claudin-1, and E-cadherin were detected in AA-treated mice. These findings provide novel insights into the potential health impact of AA consumption and the detailed mechanism for its effect on S. Typhimurium infection merit further exploration.

Tripartite relationship between gut microbiota, intestinal mucus and dietary fibers: towards preventive strategies against enteric infections

The human gut is inhabited by a large variety of microorganims involved in many physiological processes and collectively referred as to gut microbiota. Disrupted microbiome has been associated with negative health outcomes and especially could promote the onset of enteric infections. To sustain their growth and persistence within the human digestive tract, gut microbes and enteric pathogens rely on two main polysaccharide compartments, namely dietary fibers and mucus carbohydrates. Several evidences suggest that the three-way relationship between gut microbiota, dietary fibers and mucus layer could unravel the capacity of enteric pathogens to colonise the human digestive tract and ultimately lead to infection. The review starts by shedding light on similarities and differences between dietary fibers and mucus carbohydrates structures and functions. Next, we provide an overview of the interactions of these two components with the third partner, namely, the gut microbiota, under health and disease situations. The review will then provide insights into the relevance of using dietary fibers interventions to prevent enteric infections with a focus on gut microbial imbalance and impaired-mucus integrity. Facing the numerous challenges in studying microbiota-pathogen-dietary fiber-mucus interactions, we lastly describe the characteristics and potentialities of currently available in vitro models of the human gut.

Drugs in Focus: Proton Pump Inhibitors

Proton pump inhibitors (PPIs) are amongst the most commonly prescribed drugs in infants and children with the last decades witnessing a dramatic rise in their utilization. Although PPIs are clearly effective when used appropriately and have been regarded as safe drugs, there is growing evidence regarding their potential adverse effects. Although, largely based on adult data it is clear that many of these are also relevant to pediatrics. PPI use potentially affects gastrointestinal microbiota composition and function, decreases defence against pathogens resulting in increased risk for infections, interferes with absorption of minerals and vitamins leading to specific deficiencies and increased risk for bone fractures as well as interferes with protein digestion resulting in increased risk of sensitization to allergens and development of allergic diseases and eosinophilic esophagitis. An association with gastric, liver and pancreatic cancer has also been inferred from adult data but is tenuous and causation is not proven. Overall, evidence for these adverse events is patchy and not always compelling. Overall, the use of PPIs, for selected indications with a good evidence base, has significant potential benefit but carries more caution in infants and children. Pediatricians should be aware of the concerns regarding the potential adverse events associated with their use.

Occupations at risk of contracting zoonoses of public health significance in Québec

Introduction

Climate change plays an important role in the geographic spread of zoonotic diseases. Knowing which populations are at risk of contracting these diseases is critical to informing public health policies and practices. In Québec, 14 zoonoses have been identified as important for public health to guide the climate change adaptation efforts of decision-makers and researchers. A great deal has been learned about these diseases in recent years, but information on at-risk workplaces remains incomplete. The objective of this study is to paint a portrait of the occupations and sectors of economic activity at risk for the acquisition of these zoonoses.

Methods

A rapid review of the scientific literature was conducted. Databases on the Ovid and EBSCO research platforms were searched for articles published between 1995 and 2018, in English and French, on 14 zoonoses (campylobacteriosis, cryptosporidiosis, verocytotoxigenic Escherichia coli, giardiasis, listeriosis, salmonellosis, Eastern equine encephalitis, Lyme disease, West Nile virus, food botulism, Q fever, avian and swine influenza, rabies, hantavirus pulmonary syndrome) and occupational health. The literature search retrieved 12,558 articles and, after elimination of duplicates, 6,838 articles were evaluated based on the title and the abstract. Eligible articles had to address both concepts of the research issue (prioritized zoonoses and worker health). Of the 621 articles deemed eligible, 110 were selected following their full reading.

Results

Of the diseases under study, enteric zoonoses were the most frequently reported. Agriculture, including veterinary services, public administration services and medical and social services were the sectors most frequently identified in the literature.

Conclusion

The results of our study will support public health authorities and decision-makers in targeting those sectors and occupations that are particularly at risk for the acquisition of zoonoses. Doing so will ultimately optimize the public health practices of those responsible for the health of workers.

A review of Listeria monocytogenes from meat and meat products: Epidemiology, virulence factors, antimicrobial resistance and diagnosis

Listeria monocytogenes is a zoonotic food-borne pathogen that is associated with serious public health and economic implications. In animals, L. monocytogenes can be associated with clinical listeriosis, which is characterised by symptoms such as abortion, encephalitis and septicaemia. In human beings, listeriosis symptoms include encephalitis, septicaemia and meningitis. In addition, listeriosis may cause gastroenteric symptoms in human beings and still births or spontaneous abortions in pregnant women. In the last few years, a number of reported outbreaks and sporadic cases associated with consumption of contaminated meat and meat products with L. monocytogenes have increased in developing countries. A variety of virulence factors play a role in the pathogenicity of L. monocytogenes. This zoonotic pathogen can be diagnosed using both classical microbiological techniques and molecular-based methods. There is limited information about L. monocytogenes recovered from meat and meat products in African countries. This review strives to: (1) provide information on prevalence and control measures of L. monocytogenes along the meat value chain, (2) describe the epidemiology of L. monocytogenes (3) provide an overview of different methods for detection and typing of L. monocytogenes for epidemiological, regulatory and trading purposes and (4) discuss the pathogenicity, virulence traits and antimicrobial resistance profiles of L. monocytogenes.

A One Health Perspective on the Human-Companion Animal Relationship with Emphasis on Zoonotic Aspects

Over time the human-animal bond has been changed. For instance, the role of pets has changed from work animals (protecting houses, catching mice) to animals with a social function, giving companionship. Pets can be important for the physical and mental health of their owners but may also transmit zoonotic infections. The One Health initiative is a worldwide strategy for expanding collaborations in all aspects of health care for humans, animals, and the environment. However, in One Health communications the role of particularly dogs and cats is often underestimated.

OBJECTIVE

Evaluation of positive and negative One Health issues of the human-companion animal relationship with a focus on zoonotic aspects of cats and dogs in industrialized countries.

METHOD

Literature review.

RESULTS

Pets undoubtedly have a positive effect on human health, while owners are increasing aware of pet's health and welfare. The changing attitude of humans with regard to pets and their environment can also lead to negative effects such as changes in feeding practices, extreme breeding, and behavioral problems, and anthropozoonoses. For the human, there may be a higher risk of the transmission of zoonotic infections due to trends such as sleeping with pets, allowing pets to lick the face or wounds, bite accidents, keeping exotic animals, the importation of rescue dogs, and soil contact.

CONCLUSIONS

One Health issues need frequently re-evaluated as the close human-animal relationship with pet animals can totally differ compared to decennia ago. Because of the changed human-companion animal bond, recommendations regarding responsible pet-ownership, including normal hygienic practices, responsible breeding, feeding, housing, and mental and physical challenges conforming the biology of the animal are required. Education can be performed by vets and physicians as part of the One Health concept.

Proton Pump Inhibitors: The Good, Bad, and Ugly

Proton pump inhibitors (PPIs) continue to be the medication of choice for treatment of acid-related disease, with few if any overt side effects seen with daily use. They are often prescribed empirically, often in high doses and with many patients being treated with multiple PPIs without an objective diagnosis. Therefore, they are believed to be overprescribed and used without indication. In this article we discuss the appropriate clinical indications for PPIs, review in detail the major associated adverse events, and put in perspective key issues in balancing benefits and risk of this exceptional (and safe) class of drug.

Variations in microbiota composition of laboratory mice influence Citrobacter rodentium infection via variable short-chain fatty acid production

The composition of the intestinal microbiota influences the outcome of enteric infections in human and mice. However, the role of specific members and their metabolites contributing to disease severity is largely unknown. Using isogenic mouse lines harboring distinct microbiota communities, we observed highly variable disease kinetics of enteric Citrobacter rodentium colonization after infection. Transfer of communities from susceptible and resistant mice into germ-free mice verified that the varying susceptibilities are determined by microbiota composition. The strongest differences in colonization were observed in the cecum and could be maintained in vitro by coculturing cecal bacteria with C. rodentium. Cohousing of animals as well as the transfer of cultivable bacteria from resistant to susceptible mice led to variable outcomes in the recipient mice. Microbiome analysis revealed that a higher abundance of butyrate-producing bacteria was associated with the resistant phenotype. Quantification of short-chain fatty acid (SCFA) levels before and after infection revealed increased concentrations of acetate, butyrate and propionate in mice with delayed colonization. Addition of physiological concentrations of butyrate, but not of acetate and/or propionate strongly impaired growth of C. rodentium in vitro. In vivo supplementation of susceptible, antibiotic-treated and germ-free mice with butyrate led to the same level of protection, notably only when cecal butyrate concentration reached a concentration higher than 50 nmol/mg indicating a critical threshold for protection. In the recent years, commensal-derived primary and secondary bacterial metabolites emerged as potent modulators of hosts susceptibility to infection. Our results provide evidence that variations in SCFA production in mice fed fibre-rich chow-based diets modulate susceptibility to colonization with Enterobacteriaceae not only in antibiotic-disturbed ecosystems but even in undisturbed microbial communities. These findings emphasise the need for microbiota normalization across laboratory mouse lines for infection experiments with the model-pathogen C. rodentium independent of investigations of diet and antibiotic usage.

The distinct composition of the gut microbiota in each individual results in variable metabolic activity and output of these communities, which influences the host, including resistance to enteric pathogens. Lack of reproducibility in biomedical research is nowadays frequently attributed to the microbiota, but little is known about which specific members and metabolites contribute to disease severity. Here, we use genetically identical mouse lines with variable microbiota compositions on a standardized diet and observed highly variable colonization with the enteric pathogen Citrobacter rodentium without antibiotics intervention. We found the same differences in formerly germ-free animals harbouring the respective donors microbiota and also in vitro by coculturing cecal bacteria from resistant and susceptible animals with C. rodentium showing that the phenotype is fully dependent on differences in the microbiota. We analysed the microbiome composition and found a higher abundance of butyrate-producing bacteria as well as increased levels of butyrate in resistant mice. By supplementation of susceptible and germ-free animals with butyrate, we could significantly lower the levels of colonization highlighting that commensal-derived primary and secondary bacterial metabolites are highly variable between laboratory animals from different vendors and are potent modulators of hosts susceptibility to infection with C. rodentium.

Recovery of the Gut Microbiota after Antibiotics Depends on Host Diet, Community Context, and Environmental Reservoirs

Antibiotics alter microbiota composition and increase infection susceptibility. However, the generalizable effects of antibiotics on and the contribution of environmental variables to gut commensals remain unclear. To address this, we tracked microbiota dynamics with high temporal and taxonomic resolution during antibiotic treatment in a controlled murine system by isolating variables such as diet, treatment history, and housing co-inhabitants. Human microbiotas were remarkably resilient and recovered during antibiotic treatment, with transient dominance of resistant Bacteroides and taxa-asymmetric diversity reduction. In certain cases, in vitro sensitivities were not predictive of in vivo responses, underscoring the significance of host and community context. A fiber-deficient diet exacerbated microbiota collapse and delayed recovery. Species replacement through cross housing after ciprofloxacin treatment established resilience to a second treatment. Single housing drastically disrupted recovery, highlighting the importance of environmental reservoirs. Our findings highlight deterministic microbiota adaptations to perturbations and the translational potential for modulating diet, sanitation, and microbiota composition during antibiotics.

The Phylogeny and Biological Function of Gastric Juice-Microbiological Consequences of Removing Gastric Acid

Gastric juice is a unique combination of hydrochloric acid (HCl), lipase, and pepsin. Acidic gastric juice is found in all vertebrates, and its main function is to inactivate microorganisms. The phylogenetic preservation of this energy-consuming and, at times, hazardous function (acid-related diseases) reflects its biological importance. Proton pump inhibitors (PPIs) are one of the most widely used drugs in the world. Due to the reduced prevalence of Helicobacter pylori infection as well as the increased use of inhibitors of gastric acid secretion, the latter has become the most important cause of gastric hypoacidity. In the present manuscript, we review the microbiological consequences of removing gastric acidity. The resulting susceptibility to infections has not been studied extensively, and focus has mainly been restricted to bacterial and parasitic agents only. The strongest evidence concerning the relationship between hypochlorhydria and predisposition to infections relates to bacterial infections affecting the gastrointestinal tract. However, several other clinical settings with increased susceptibility to infections due to inhibited gastric acidity are discussed. We also discuss the impact of hypochlorhydria on the gut microbiome.

Increasing Frequencies of Antibiotic Resistant Non-typhoidal Salmonella Infections in Michigan and Risk Factors for Disease

Non-typhoidal Salmonella (NTS) are important enteric pathogens causing over 1 million foodborne illnesses in the U.S. annually. The widespread emergence of antibiotic resistance in NTS isolates has limited the availability of antibiotics that can be used for therapy. Since Michigan is not part of the FoodNet surveillance system, few studies have quantified antibiotic resistance frequencies and identified risk factors for NTS infections in the state. We obtained 198 clinical NTS isolates via active surveillance at four Michigan hospitals from 2011 to 2014 for classification of serovars and susceptibility to 24 antibiotics using broth microdilution. The 198 isolates belonged to 35 different serovars with Enteritidis (36.9%) predominating followed by Typhimurium (19.5%) and Newport (9.7%), though the proportion of each varied by year, residence, and season. The number of Enteritidis and Typhimurium cases was higher in the summer, while Enteritidis cases were significantly more common among urban vs. rural residents. A total of 30 (15.2%) NTS isolates were resistant to ≥1 antibiotic and 15 (7.5%) were resistant to ≥3 antimicrobial classes; a significantly greater proportion of Typhimurium isolates were resistant compared to Enteritidis isolates and an increasing trend in the frequency of tetracycline resistance and multidrug resistance was observed over the 4-year period. Resistant infections were associated with longer hospital stays as the mean stay was 5.9 days for patients with resistant isolates relative to 4.0 days for patients infected with susceptible isolates. Multinomial logistic regression indicated that infection with serovars other than Enteritidis [Odds ratio (OR): 3.8, 95% confidence interval (CI): 1.23-11.82] as well as infection during the fall (OR: 3.0; 95% CI: 1.22-7.60) were independently associated with resistance. Together, these findings demonstrate the importance of surveillance, monitoring resistance frequencies, and identifying risk factors that can aid in the development of new prevention strategies.

Risk factors of Salmonella infection in laying hens in Menoua Division, Western region of Cameroon (Central Africa)

Salmonella infections in poultry farms are overlooked in many African countries; yet these infections are mostly zoonotic with impact on both poultry industry and public health. Considering the impact of Salmonella in laying hens, and the role of laying hens as a source of Salmonella outbreak in human, knowledge of the status of Salmonella on laying hen farms as well as the factors influencing the presence of Salmonella is important. In a cross sectional study, cloacal swabs were collected from 270 commercial laying hens on 27 farms located in Menoua Division. These samples were cultured on standard media. A questionnaire was used to collect information on animals, farms and farmer's characteristics. The prevalence of Salmonella was 93.34%; three zoonotic isolates namely S. Enteritidis (75.90%), S. Paratyphi (11.90%), and S. Typhimurium (5.60%) were identified. The location of farms was significantly associated with presence of Salmonella, and the risk of infection was 10-fold higher in Nkong-ni than Santchou (p < 0.05). Other potential risk factors such as flock size, age of the farm (infrastructure), or water source were not associated with Salmonella infection. The prophylactic measures against avian diseases in the country must include measures against Salmonella to protect poultry industry and public health.

Salmonella Serotypes: A Novel Measure of Association with Foodborne Transmission

Most nontyphoidal Salmonella (NTS) illnesses in the United States are thought to be foodborne. However, transmission routes likely vary among the different serotypes. We developed a relative ranking of NTS serotypes according to the strength of their association with foodborne transmission. We used Laboratory-based Enteric Disease Surveillance data to estimate the proportion of infections for each Salmonella serotype reported from 1998 to 2015 and Foodborne Disease Outbreak Surveillance System data to calculate the proportion of foodborne outbreak-associated Salmonella illnesses caused by each serotype. We calculated the ratios of these proportions to create a foodborne relatedness (FBR) measure for each serotype. Of the top 20 serotypes, Saintpaul (2.14), Heidelberg (1.61), and Berta (1.48) had the highest FBR measures; Mississippi (0.01), Bareilly (0.13), and Paratyphi B variant L(+) tartrate(+) (0.20) had the lowest. The FBRs for the three most prevalent serotypes were 1.22 for Enteritidis, 0.77 for Typhimurium, and 1.16 for Newport. This method provides a quantitative approach to estimating the relative differences in the likelihood that an illness caused by a particular serotype was transmitted by food, which may aid in tailoring strategies to prevent Salmonella illnesses and guide future research into serotype-specific source attribution.

Attributable sources of community-acquired carriage of Escherichia coli containing β-lactam antibiotic resistance genes: a population-based modelling study

BACKGROUND

Extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC), plasmid-mediated AmpC-producing E coli (pAmpC-EC), and other bacteria are resistant to important β-lactam antibiotics. ESBL-EC and pAmpC-EC are increasingly reported in animals, food, the environment, and community-acquired and health-care-associated human infections. These infections are usually preceded by asymptomatic carriage, for which attributions to animal, food, environmental, and human sources remain unquantified.

METHODS

In this population-based modelling study, we collected ESBL and pAmpC gene data on the Netherlands population for 2005-17 from published datasets of gene occurrences in E coli isolates from different sources, and from partners of the ESBL Attribution Consortium and the Dutch National Antimicrobial Surveillance System. Using these data, we applied an established source attribution model based on ESBL-EC and pAmpC-EC prevalence and gene data for humans, including high-risk populations (ie, returning travellers, clinical patients, farmers), farm and companion animals, food, surface freshwater, and wild birds, and human exposure data, to quantify the overall and gene-specific attributable sources of community-acquired ESBL-EC and pAmpC-EC intestinal carriage. We also used a simple transmission model to determine the basic reproduction number (R₀) in the open community.

FINDINGS

We identified 1220 occurrences of ESBL-EC and pAmpC-EC genes in humans, of which 478 were in clinical patients, 454 were from asymptomatic carriers in the open community, 103 were in poultry and pig farmers, and 185 were in people who had travelled out of the region. We also identified 6275 occurrences in non-human sources, including 479 in companion animals, 4026 in farm animals, 66 in wild birds, 1430 from food products, and 274 from surface freshwater. Most community-acquired ESBL-EC and pAmpC-EC carriage was attributed to human-to-human transmission within or between households in the open community (60·1%, 95% credible interval 40·0-73·5), and to secondary transmission from high-risk groups (6·9%, 4·1-9·2). Food accounted for 18·9% (7·0-38·3) of carriage, companion animals for 7·9% (1·4-19·9), farm animals (non-occupational contact) for 3·6% (0·6-9·9), and swimming in freshwater and wild birds (ie, environmental contact) for 2·6% (0·2-8·7). We derived an R₀ of 0·63 (95% CI 0·42-0·77) for intracommunity transmission.

INTERPRETATION

Although humans are the main source of community-acquired ESBL-EC and pAmpC-EC carriage, the attributable non-human sources underpin the need for longitudinal studies and continuous monitoring, because intracommunity ESBL-EC and pAmpC-EC spread alone is unlikely to be self-maintaining without transmission to and from non-human sources.

FUNDING

1Health4Food, Dutch Ministry of Economic Affairs, and the EU's Horizon-2020 through One-Health European Joint Programme.

Paediatric Salmonellosis-Differences between Tropical and Sub-Tropical Regions of Queensland, Australia

Salmonellosis is an important cause of morbidity in tropical regions.This study aims to describe the epidemiology of non-typhoidal Salmonellae (NTS) in children presenting to public hospitals in Queensland, Australia, over the past 20 years, with a focus on differences between tropical and sub-tropical zones in the region. This is a retrospective and descriptive cohort study of 8162 NTS positive samples collected in 0–17-year-olds from the Queensland public hospital pathology database (Auslab) over a 20-year period from 1997 to 2016. There were 2951 (36.2%) positive NTS samples collected in tropical zones and 5211 (63.8%) in the sub-tropical zones of Queensland, with a total of 8162 over the region. The tropical zone contributed a disproportionately higher number of positive NTS samples by population sub-analysis. Of the specimens collected, 7421 (90.92%) were faecal, 505 (6.2%) blood, 161 (1.97%) urine, 13 (0.16%) cerebrospinal fluid (CSF) and 62 of other origin. Other categories of specimen types isolated include swab, fluid, aspirate, lavage, bone, tissue, isolate and pus, and these were not included in sub-analysis. The most commonly identified serovars were Salmonella Typhimurium, Salmonella Virchow and Salmonella Saintpaul. This is the first and largest study that emphasises the high burden of invasive and non-invasive NTS infections resulting in hospital presentations in the paediatric population of tropical north Queensland, compared to the sub-tropics.

Association between prior antibiotic therapy and subsequent risk of community-acquired infections: a systematic review

Background

Antibiotic use can have negative unintended consequences including disruption of the human microbiota, which is thought to protect against pathogen overgrowth. We conducted a systematic review to assess whether there is an association between exposure to antibiotics and subsequent risk of community-acquired infections.

Methods

We searched MEDLINE, EMBASE and Web of Science for studies published before 30 June 2017, examining the association between antibiotic use and subsequent community-acquired infection. Infections caused by Clostridium difficile and fungal organisms were excluded. Studies focusing exclusively on resistant organism infections were also excluded.

Results

Eighteen of 22588 retrieved studies met the inclusion criteria. From these, 16 studies reported a statistically significant association between antibiotic exposure and subsequent risk of community-acquired infection. Infections associated with prior antibiotic use included Campylobacter jejuni infection (one study), recurrent furunculosis (one study), invasive Haemophilus influenzae type b infection (one study), infectious mastitis (one study), meningitis (one study), invasive pneumococcal disease (one study), Staphylococcus aureus skin infection (one study), typhoid fever (two studies), recurrent boils and abscesses (one study), upper respiratory tract infection and urinary tract infection (one study) and Salmonella infection (five studies), although in three studies on Salmonella infection the effect was of marginal statistical significance.

Conclusions

We found an association between prior antibiotic use and subsequent risk of a diverse range of community-acquired infections. Gastrointestinal and skin and soft tissue infections were most frequently found to be associated with prior antibiotic exposure. Our findings support the hypothesis that antibiotic use may predispose to future infection risk, including infections caused by both antibiotic-resistant and non-resistant organisms.

Forecasting the incidence of salmonellosis in seniors in Canada: A trend analysis and the potential impact of the demographic shift

Salmonella infections remain an important public health issue in Canada and worldwide. Although the majority of Salmonella cases are self-limiting, some will lead to severe symptoms and occasionally severe invasive infections, especially in vulnerable populations such as seniors. This study was performed to assess temporal trends of Salmonella cases in seniors over 15 years (2014–2028) and assess possible impact of demographic shift on national incidence; taking into account of trends in other age groups. The numbers of reported Salmonella cases in seniors (60 years and over) in eight provinces and territories for a period of fifteen years were analysed (1998–2013) using a time-adjusted Poisson regression model. With the demographic changes predicted in the age-structure of the population and in the absence of any targeted interventions, our analysis showed the incidence of Salmonella cases in seniors could increase by 16% by 2028 and the multi-provincial incidence could increase by 5.3%. As a result, the age distribution amongst the Salmonella cases is expected to change with a higher proportion of cases in seniors and a smaller proportion in children (0–4 years old). Over the next decades, cases of infection, hospitalizations and deaths associated with Salmonella in seniors could represent a challenge to public health due to an aging population in Canada. As life expectancy increases in Canada, identification of unique risk factors and targeted prevention in seniors should be pursued to reduce the impact of the demographic shift on disease incidence.

The role of domestic reservoirs in domestically acquired Salmonella infections in Norway: epidemiology of salmonellosis, 2000-2015, and results of a national prospective case-control study, 2010-2012

In Norway, incidence of sporadic domestically acquired salmonellosis is low, and most frequently due to Salmonalla Typhimurium. We investigated the risk factors for sporadic Salmonella infections in Norway to improve control and prevention measures. Surveillance data for all Salmonella infections from 2000 to 2015 were analysed for seasonality and proportion associated with domestic reservoirs, hedgehogs and wild birds. A prospective case–control study was conducted from 2010 to 2012 by recruiting cases from the Norwegian Surveillance System for Communicable Diseases and controls from the Norwegian Population Registry (389 cases and 1500 controls). Univariable analyses using logistic regression were conducted and a multivariable model was developed using regularised/penalised logistic regression. In univariable analysis, eating snow, dirt, sand or playing in a sandbox (aOR 4.14; CI 2.15–7.97) was associated with salmonellosis. This was also the only exposure significantly associated with illness in the multivariable model. Since 2004, 34.2% (n = 354) of S. Typhimuirum cases had an MLVA profile linked to a domestic reservoir. A seasonal trend with a peak in August for all Salmonella types and in February for S. Typhimurium was observed. Indirect exposure to domestic reservoirs remains a source of salmonellosis in Norway, particularly for children. Information to the public about avoiding environmental exposure should be strengthened and initiatives to combat salmonellosis in the food chain should be reinforced.

Tracing Back the Source of an Outbreak of Salmonella Typhimurium; National Outbreak Linked to the Consumption of Raw and Undercooked Beef Products, the Netherlands, October to December 2015

INTRODUCTION

On 23 October 2015, six related cases with gastroenteritis called the Netherlands Food and Consumer Product Safety Authority. They suspected filet américain, a raw beef spread, to be the source of infection. Leftovers and stool samples tested positive for Salmonella Typhimurium. Multiple locus variable-number of tandem repeat analysis (MLVA) revealed a MLVA pattern (02-23-08-08-212), which had not been detected in the Netherlands before. Concomitantly, an increase of this MLVA type was observed in the national Salmonella surveillance, amounting to 46 cases between 26 October and 9 December.

METHODS

To investigate whether filet américain or an alternative (related) source could  be linked to surveillance-reported cases, cases (n=38) were invited to complete a questionnaire and upstream source tracing to map the food supply chain was initiated.

RESULTS

Rapid interdisciplinary action resulted in identification of a contaminated 46-ton batch of beef distributed via a Dutch deboning plant as the likely source of infection. In total, 24/29 respondents (83%) could be linked to the incriminated batch of beef products (predominantly filet américain and minced beef).

DISCUSSION

Repeated identification of raw meat products as a source of infection emphasizes the importance of awareness of the risk of infection when handling or consuming these products. Improved measures and procedures on product labelling, pre-treatment or product testing should be considered.

Risk factors for sporadic Giardia infection in the USA: a case-control study in Colorado and Minnesota

Giardia duodenalis is the most common intestinal parasite of humans in the USA, but the risk factors for sporadic (non-outbreak) giardiasis are not well described. The Centers for Disease Control and Prevention and the Colorado and Minnesota public health departments conducted a case-control study to assess risk factors for sporadic giardiasis in the USA. Cases (N = 199) were patients with non-outbreak-associated laboratory-confirmed Giardia infection in Colorado and Minnesota, and controls (N = 381) were matched by age and site. Identified risk factors included international travel (aOR = 13.9; 95% CI 4.9-39.8), drinking water from a river, lake, stream, or spring (aOR = 6.5; 95% CI 2.0-20.6), swimming in a natural body of water (aOR = 3.3; 95% CI 1.5-7.0), male-male sexual behaviour (aOR = 45.7; 95% CI 5.8-362.0), having contact with children in diapers (aOR = 1.6; 95% CI 1.01-2.6), taking antibiotics (aOR = 2.5; 95% CI 1.2-5.0) and having a chronic gastrointestinal condition (aOR = 1.8; 95% CI 1.1-3.0). Eating raw produce was inversely associated with infection (aOR = 0.2; 95% CI 0.1-0.7). Our results highlight the diversity of risk factors for sporadic giardiasis and the importance of non-international-travel-associated risk factors, particularly those involving person-to-person transmission. Prevention measures should focus on reducing risks associated with diaper handling, sexual contact, swimming in untreated water, and drinking untreated water.

The Risk of Community-Acquired Enteric Infection in Proton Pump Inhibitor Therapy: Systematic Review and Meta-analysis

BACKGROUND

Previous meta-analyses suggest that users of proton pump inhibitors (PPIs) have a higher risk of developing enteric infections compared with nonusers. These previous meta-analyses have considerable heterogeneity, and it is not clear whether the effect of PPIs is different for different types of microorganisms.

OBJECTIVE

The aim of this study is to update previous meta-analyses, concentrating on enteric infection in community settings and exploring potential sources of heterogeneity.

METHODS

A systematic search was conducted on electronic databases (all available years until November 2017). PubMed, EMBASE, Cochrane, and Web of Science were searched using specific keywords related to PPI therapy and community-acquired enteric infection. Eligible studies were selected based on prespecified criteria.

RESULTS

A total of 9 observational studies evaluating community-acquired enteric infection were eligible, including 12 separate analyses. The meta-analysis showed that PPI users have an increased risk of developing community-acquired enteric infection (pooled odds ratio [OR] = 4.28; 95% CI = 3.01-6.08). There was significant heterogeneity between the studies ( I² = 85%; P < 0.001), which was partly explained by type of microorganism. The strength of the association was similar for Salmonella (pooled OR = 4.84; 95% CI = 2.75-8.54; I² = 58.7%; P = 0.064) and Campylobacter (pooled OR = 5.09; 95% CI = 3-8.64; I² = 81%; P < 0.001) but lower for studies that combined all bacteria (pooled OR = 2.42; 95% CI = 0.96-6.14; I² = 94.3%; P < 0.001).

CONCLUSION

PPI users have an increased risk of developing community-acquired enteric infections compared with nonusers. The heterogeneity was partially explained by type of microorganism; the association is stronger for Salmonella and Campylobacter than for all bacteria combined.

Enhancement of IFNγ Production by Distinct Commensals Ameliorates Salmonella-Induced Disease

The microbiota contributes to colonization resistance against invading pathogens by competing for metabolites, producing inhibitory substances, and priming protective immune responses. However, the specific commensal bacteria that promote host resistance and immune-mediated protection remain largely elusive. Using isogenic mouse lines with distinct microbiota profiles, we demonstrate that severity of disease induced by enteric Salmonella Typhimurium infection is strongly modulated by microbiota composition in individual lines. Transferring a restricted community of cultivable intestinal commensals from protected into susceptible mice decreases S. Typhimurium tissue colonization and consequently disease severity. This reduced tissue colonization, along with ameliorated weight loss and prolonged survival, depends on microbiota-enhanced IFNγ production, as IFNγ-deficient mice do not exhibit protective effects. Innate cells and CD4⁺ T cells increase in number and show high levels of IFNγ after transfer of the commensal community. Thus, distinct microbiota members prevent intestinal Salmonella infection by enhancing antibacterial IFNγ responses.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Increased colon cancer risk after severe Salmonella infection

BACKGROUND

Colon cancer constitutes one of the most frequent malignancies. Previous studies showed that Salmonella manipulates host cell signaling pathways and that Salmonella Typhimurium infection facilitates colon cancer development in genetically predisposed mice. This epidemiological study examined whether severe Salmonella infection, usually acquired from contaminated food, is associated with increased colon cancer risk in humans.

METHODS AND FINDINGS

We performed a nationwide registry-based study to assess colon cancer risk after diagnosed Salmonella infection. National infectious disease surveillance records (1999-2015) for Dutch residents aged ≥20 years when diagnosed with salmonellosis (n = 14,264) were linked to the Netherlands Cancer Registry. Salmonella-infected patients were laboratory-confirmed under medical consultation after 1-2 weeks of illness. These datasets also contained information on Salmonella serovar and type of infection. Colon cancer risk (overall and per colon subsite) among patients with a diagnosed Salmonella infection was compared with expected colon cancer risk in the general population. Data from the nationwide registry of histo- and cytopathology (PALGA) and Statistics Netherlands (CBS) allowed assessing potential effects of age, gender, latency, socioeconomic status, genetic predisposition, inflammatory bowel disease (IBD), and tumor features. We found that compared to the general population, colon cancer risk was significantly increased (standardized incidence ratio [SIR] 1.54; 95%CI 1.09-2.10) among patients with Salmonella infection diagnosed <60 years of age. Such increased risk concerned specifically the ascending/transverse colon (SIR 2.12; 95%CI 1.38-3.09) after S. Enteritidis infection (SIR 2.97; 95%CI 1.73-4.76). Salmonellosis occurred more frequently among colon cancer patients with pre-infectious IBD, a known risk factor for colon cancer. Colon tumors of patients with a history of Salmonella infection were mostly of low grade.

CONCLUSIONS

Patients diagnosed with severe salmonellosis have an increased risk of developing cancer in the ascending/transverse parts of the colon. This risk concerns particularly S. Enteritidis infection, suggesting a contribution of this major foodborne pathogen to colon cancer development.

Proton-pump inhibitors: understanding the complications and risks

Proton-pump inhibitors (PPIs) are the most effective therapy for the full spectrum of gastric-acid-related diseases. However, in the past decade, a steadily increasing list of complications following long-term use of PPIs has been reported. Their potent acid-suppressive action induces several structural and functional changes within the gastric mucosa, including fundic gland polyps, enterochromaffin-like cell hyperplasia and hypergastrinaemia, which can be exaggerated in the presence of Helicobacter pylori infection. As discussed in this Review, most associations of PPIs with severe adverse events are not based on sufficient evidence because of confounding factors and a lack of plausible mechanisms. Thus, a causal relationship remains unproven in most associations, and further studies are needed. Awareness of PPI-associated risks should not lead to anxiety in patients but rather should induce the physician to consider the appropriate dosing and duration of PPI therapy, including long-term monitoring strategies in selected groups of patients because of their individual comorbidities and risk factors.

Comparison of sporadic cases of Salmonella Typhimurium with other Salmonella serotypes in Castellon (Spain): case-case study

INTRODUCTION

Salmonella infections (SI) are common in Spain. The aim of this study was to appraise risk factors and the clinical characteristics of sporadic Salmonella Typhimurium infections compared with other sporadic salmonella serotype infections (OSI).

METHODS

From September 2014 to August 2015, a case-case study was carried out by the Epidemiology Division of the Public Health Centre of Castellon. Case 1 consisted of patients with sporadic S. Typhimurium infections, while case 2 comprised OSI patients, assessed according to the stool cultures analyzed by the Microbiology Laboratories of Hospital General de Castellon and Hospital de La Plana in Vila-real. Patients from detected outbreaks were not included. The salmonella serotype was identified by the National Centre of Microbiology (Madrid).

RESULTS

The total number of SI patients reported was 327, 242 of whom were studied (74.0%). 148 patients had sporadic S. Typhimurium infection and 64 had OSI, with median ages of 4 and 8.5 years, respectively. Sporadic S. Typhimurium infection patients presented more blood in feces and diarrhea episodes. Consumption of pork meat (OR=2.22; 95% CI 1.12-4.43), cold pork meats (OR=2.49; 95% CI 1.32-4.68) and playing in the dirt (OR=3.02; 95% CI 1.55-5.88), were associated with sporadic S. Typhimurium infection. In the 0-4 year-old group, the associated factors were consumption of cold pork meats, omelets and female gender. In the 5-year-old and over group, only playing in soil was associated with sporadic S. Typhimurium infection.

CONCLUSIONS

The consumption of pork and omelets, as well as playing in the dirt, were the main factors associated with infection. Children were most affected by sporadic S. Typhimurium infection.

Attribution of human infections with Shiga toxin-producing Escherichia coli (STEC) to livestock sources and identification of source-specific risk factors, The Netherlands (2010-2014)

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen of public health concern whose sources and transmission routes are difficult to trace. Using a combined source attribution and case-control analysis, we determined the relative contributions of four putative livestock sources (cattle, small ruminants, pigs, poultry) to human STEC infections and their associated dietary, animal contact, temporal and socio-econo-demographic risk factors in the Netherlands in 2010/2011-2014. Dutch source data were supplemented with those from other European countries with similar STEC epidemiology. Human STEC infections were attributed to sources using both the modified Dutch model (mDM) and the modified Hald model (mHM) supplied with the same O-serotyping data. Cattle accounted for 48.6% (mDM) and 53.1% (mHM) of the 1,183 human cases attributed, followed by small ruminants (mDM: 23.5%; mHM: 25.4%), pigs (mDM: 12.5%; mHM: 5.7%) and poultry (mDM: 2.7%; mHM: 3.1%), whereas the sources of the remaining 12.8% of cases could not be attributed. Of the top five O-serotypes infecting humans, O157, O26, O91 and O103 were mainly attributed to cattle (61%-75%) and O146 to small ruminants (71%-77%). Significant risk factors for human STEC infection as a whole were the consumption of beef, raw/undercooked meat or cured meat/cold cuts. For cattle-attributed STEC infections, specific risk factors were consuming raw meat spreads and beef. Consuming raw/undercooked or minced meat were risk factors for STEC infections attributed to small ruminants. For STEC infections attributed to pigs, only consuming raw/undercooked meat was significant. Consuming minced meat, raw/undercooked meat or cured meat/cold cuts were associated with poultry-attributed STEC infections. Consuming raw vegetables was protective for all STEC infections. We concluded that domestic ruminants account for approximately three-quarters of reported human STEC infections, whereas pigs and poultry play a minor role and that risk factors for human STEC infection vary according to the attributed source.

A combined case-control and molecular source attribution study of human Campylobacter infections in Germany, 2011-2014

Campylobacter infection is the most commonly notified bacterial enteritis in Germany. We performed a large combined case-control and source attribution study (Nov 2011-Feb 2014) to identify risk factors for sporadic intestinal Campylobacter infections and to determine the relative importance of various animal sources for human infections in Germany. We conducted multivariable logistic regression analysis to identify risk factors. Source attribution analysis was performed using the asymmetric island model based on MLST data of human and animal/food isolates. As animal sources we considered chicken, pig, pet dog or cat, cattle, and poultry other than chicken. Consumption of chicken meat and eating out were the most important risk factors for Campylobacter infections. Additional risk factors were preparation of poultry meat in the household; preparation of uncooked food and raw meat at the same time; contact with poultry animals; and the use of gastric acid inhibitors. The mean probability of human C. jejuni isolates to originate from chickens was highest (74%), whereas pigs were a negligible source for C. jejuni infections. Human C. coli isolates were likely to originate from chickens (56%) or from pigs (32%). Efforts need to be intensified along the food chain to reduce Campylobacter load, especially on chicken meat.

The Safety of Appropriate Use of Over-the-Counter Proton Pump Inhibitors: An Evidence-Based Review and Delphi Consensus

The availability of over-the-counter (OTC) proton pump inhibitors (PPIs) for the short-term (2 weeks) management of frequent heartburn (≥2 days/week) has increased markedly, yet evidence-based recommendations have not been developed. A panel of nine international experts in gastroesophageal reflux disease developed consensus statements regarding the risks and benefits of OTC PPIs using a modified Delphi process. Consensus (based on ≥80% approval) was reached through multiple rounds of remote voting and a final round of live voting. To identify relevant data, the available literature was searched and summarized. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system terminology was used to rate the quality of evidence and strength of recommendations; consensus was based on ≥2/3 agreement. After 4 rounds of review, consensus was achieved for 18 statements. Notably, the available data did not directly reflect OTC use, but instead, prescription use; therefore, extrapolations to the OTC setting were often necessary. This limitation is regrettable, but it justifies performing this exercise to provide evidence-based expert opinion on a widely used class of drugs. The panel determined that using OTC PPIs according to label instructions is unlikely to mask the symptoms of esophageal or gastric cancer or adversely impact the natural history of related precursor conditions. OTC PPIs are not expected to substantially affect micronutrient absorption or bone mineral density or cause community-acquired pneumonia, Clostridium difficile infection, or cardiovascular adverse events. However, OTC PPI use may be associated with slightly increased risks for infectious diarrhea, certain idiosyncratic reactions, and cirrhosis-related spontaneous bacterial peritonitis. The available evidence does not suggest that OTC PPI use consistent with label instructions is associated with substantial health risks. To minimize potential risks, healthcare professionals and consumers must actively participate in decision making when managing reflux-related symptoms in the self-care setting.

New paradigms for Salmonella source attribution based on microbial subtyping

Microbial subtyping is the most common approach for Salmonella source attribution. Typically, attributions are computed using frequency-matching models like the Dutch and Danish models based on phenotyping data (serotyping, phage-typing, and antimicrobial resistance profiling). Herewith, we critically review three major paradigms facing Salmonella source attribution today: (i) the use of genotyping data, particularly Multi-Locus Variable Number of Tandem Repeats Analysis (MLVA), which is replacing traditional Salmonella phenotyping beyond serotyping; (ii) the integration of case-control data into source attribution to improve risk factor identification/characterization; (iii) the investigation of non-food sources, as attributions tend to focus on foods of animal origin only. Population genetics models or simplified MLVA schemes may provide feasible options for source attribution, although there is a strong need to explore novel modelling options as we move towards whole-genome sequencing as the standard. Classical case-control studies are enhanced by incorporating source attribution results, as individuals acquiring salmonellosis from different sources have different associated risk factors. Thus, the more such analyses are performed the better Salmonella epidemiology will be understood. Reparametrizing current models allows for inclusion of sources like reptiles, the study of which improves our understanding of Salmonella epidemiology beyond food to tackle the pathogen in a more holistic way.

Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104

It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella enterica serovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315 S. Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonella from pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections.

Salmonella Typhimurium and Outbreaks of Egg-Associated Disease in Australia, 2001 to 2011

INTRODUCTION

Salmonellosis is a significant public health problem, with eggs frequently identified as a food vehicle during outbreak investigations. Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis are the two most frequently identified causes of egg-associated disease in industrialized countries. In Australia, a comprehensive review of egg-associated outbreaks has not been previously undertaken.

METHODS

Using a national register of foodborne outbreaks, we undertook a descriptive review of egg-associated outbreaks between 2001 and 2011. Included in our review was additional detail from the findings of trace back investigations conducted to the farm level. Evidence classifications were developed and applied to each outbreak based on descriptive and analytical epidemiology, food safety investigations, and microbiological testing of clinical, food, and trace back-derived samples.

RESULTS

Over the study period, the proportion of foodborne Salmonella outbreaks linked to eggs increased significantly (p < 0.001). In total, 166 outbreaks were identified, with 90% caused by Salmonella Typhimurium. The majority of outbreaks were linked to commercial food providers, with raw egg use the major contributing factor. These events resulted in more than 3200 cases, more than 650 hospitalizations, and at least 4 deaths. Fifty-four percent of investigations used analytical epidemiology, food microbiology, and trace back microbiology to demonstrate links between human illness and eggs. Trace back investigations identified S. enterica indistinguishable from outbreak-associated clinical or food samples on 50% of sampled egg farms.

CONCLUSION

Effective control of egg-associated salmonellosis remains a challenge in Australia, with Salmonella Typhimurium dominating as the causative serotype in outbreak events. Although outbreaks predominantly occur in the settings of restaurants, the high recovery rate of indistinguishable Salmonella on epidemiologically implicated egg farms suggests that further efforts to minimize infection pressure at the primary production level are needed in Australia.

Proton pump inhibitors and gastroenteritis

An association between proton pump inhibitor (PPI) therapy and bacterial gastroenteritis has been suggested as well as contradicted. The aim of this study was to examine the association between the use of PPIs and occurrence of bacterial gastroenteritis in the prospective Rotterdam Study. The Rotterdam Study is a population-based cohort study among 14,926 subjects aged 45 years and older with up to 24 years of follow-up. Analyses were performed with a generalized estimating equations method in participants who handed-in a diagnostic stool sample. Furthermore, a nested case–control analysis was performed using the total cohort as a reference group. A bacterial microorganism was isolated in 125 samples, whereas 1174 samples were culture negative. In the generalized estimating equations analysis, we found that participants with a bacterial gastroenteritis were more likely than controls to be current users of PPIs (adjusted OR 1.94; 95 % CI 1.15–3.25). Different sensitivity analyses did not change this result. A considerably higher effect was observed (adjusted OR 6.14; 95 % CI 3.81–9.91), using the total cohort as a reference in a nested case–control analysis. Current PPI therapy is associated with an increased risk of bacterial gastroenteritis. However, by reducing the risk of selection and information bias in our study design, we demonstrated that the effect is lower than previously assumed.

Human Campylobacteriosis in Luxembourg, 2010-2013: A Case-Control Study Combined with Multilocus Sequence Typing for Source Attribution and Risk Factor Analysis

Campylobacteriosis has increased markedly in Luxembourg during recent years. We sought to determine which Campylobacter genotypes infect humans, where they may originate from, and how they may infect humans. Multilocus sequence typing was performed on 1153 Campylobacter jejuni and 136 C. coli human strains to be attributed to three putative animal reservoirs (poultry, ruminants, pigs) and to environmental water using the asymmetric island model. A nationwide case-control study (2010-2013) for domestic campylobacteriosis was also conducted, including 367 C. jejuni and 48 C. coli cases, and 624 controls. Risk factors were investigated by Campylobacter species, and for strains attributed to different sources using a combined case-control and source attribution analysis. 282 sequence types (STs) were identified: ST-21, ST-48, ST-572, ST-50 and ST-257 were prevailing. Most cases were attributed to poultry (61.2%) and ruminants (33.3%). Consuming chicken outside the home was the dominant risk factor for both Campylobacter species. Newly identified risk factors included contact with garden soil for either species, and consuming beef specifically for C. coli. Poultry-associated campylobacteriosis was linked to poultry consumption in wintertime, and ruminant-associated campylobacteriosis to tap-water provider type. Besides confirming chicken as campylobacteriosis primary source, additional evidence was found for other reservoirs and transmission routes.

Comparison of the occurrence and survival of fecal indicator bacteria in recreational sand between urban beach, playground and sandbox settings in Toronto, Ontario

While beach sands are increasingly being studied as a reservoir of fecal indicator bacteria (FIB), less is known about the occurrence of FIB in other recreational sands (i.e., sandboxes and playgrounds). In this study, different culture-based FIB enumeration techniques were compared and microbial source tracking assays were conducted on recreational sand samples from beaches, playgrounds and sandboxes around Toronto, ON. FIB were detected in every sand sample (n=104) with concentrations not changing significantly over the five month sampling period. Concentrations of FIB and a gull-specific DNA marker were significantly higher in foreshore beach sands, and indicated these were a more significant reservoir of FIB contamination than sandbox or playground sands. Human- and dog-specific contamination markers were not detected. All culture-based FIB enumeration techniques were consistent in identifying the elevated FIB concentrations associated with foreshore beach sands. However, significant differences between differential agar media, IDEXX and Aquagenx Compartment Bag Test were observed, with DC media and Enterolert being the most sensitive methods to detect Escherichia coli and enterococci, respectively. To better understand the elevated occurrence of E. coli in foreshore sands, microcosm survival experiments were conducted at two different temperatures (15 °C and 28 °C) using non-sterile saturated foreshore beach sands collected from two urban freshwater beaches with different sand type (fine grain and sand-cobble). Microcosms were inoculated with a mixture of eight sand-derived E. coli strains and sampled over a 28-day period. E. coli levels were found to decline in all microcosms, although survival was significantly greater in the finer sand and at the cooler temperature (15 °C). These results indicate that FIB can be widespread in any type of recreational sand and, while E. coli can survive for many weeks, it is most likely to accumulate in cooler fine-grain sand as occurs below the foreshore sand surface.