Cost of Salmonella Infections in Australia, 2015.

Gastroenteritis caused from infections with Salmonella enterica (salmonellosis) causes significant morbidity in Australia. In addition to acute gastroenteritis, approximately 8.8% of people develop irritable bowel syndrome (IBS) and 8.5% of people develop reactive arthritis (ReA). We estimated the economic cost of salmonellosis and associated sequel illnesses in Australia in a typical year circa 2015. We estimated incidence, hospitalizations, other health care usage, absenteeism, and premature mortality for four age groups using a variety of complementary data sets. We calculated direct costs (health care) and indirect costs (lost productivity and premature mortality) by using Monte Carlo simulation to estimate 90% credible intervals (CrI) around our point estimates. We estimated that 90,833 cases, 4,312 hospitalizations, and 19 deaths occurred from salmonellosis in Australia circa 2015 at a direct cost of AUD 23.8 million (90% CrI, 19.3 to 28.9 million) and a total cost of AUD 124.4 million (90% CrI, 107.4 to 143.1 million). When IBS and ReA were included, the estimated direct cost was 35.7 million (90% CrI, 29.9 to 42.7 million) and the total cost was AUD 146.8 million (90% CrI, 127.8 to 167.9 million). Foodborne infections were responsible for AUD 88.9 million (90% CrI, 63.9 to 112.4 million) from acute salmonellosis and AUD 104.8 million (90% CrI, 75.5 to 132.3 million) when IBS and ReA were included. Targeted interventions to prevent illness could considerably reduce costs and societal impact from Salmonella infections and sequel illnesses in Australia.

Epidemiological Survey and Retrospective Analysis of Salmonella Infections between 2000 and 2017 in Warmia and Masuria Voivodship in Poland.

Background and Objectives: Salmonellosis is a major foodborne bacterial infection throughout the world. Epidemiological surveillance is one of the key factors to reduce the number of infections caused by this pathogen in both humans and animals. The first outcome measure was the prevalence of non-typhoid Salmonella (NTS) infections between 2000 and 2017 among the population of the predominantly agricultural and touristic Polish region of Warmia and Masuria (WaM). The second outcome measure was the comparison of the NTS hospitalization rate of all registered NTS cases, an investigation of the monthly reports of infections, and the exploration of the annual minimal and maximal NTS infection number in WaM in the above-mentioned time period. The last outcome was a comparison of the prevalence of NTS infections in the region and in its administrative districts by considering both rural and urban municipalities three years before and three years after the accession of Poland into the European Union (EU) in 2004. Materials and Methods: The total number of infections and hospitalizations in the 19 districts of the WaM voivodship in Poland was registered monthly between 2000⁻2017 by the Provincial Sanitary-Epidemiological Station in Olsztyn, Poland. Results: Between 2000 and 2017, the number of diagnosed salmonellosis cases decreased significantly in WaM; the decrease was higher in urban districts than in rural ones, and the ratio of hospitalizations and the total number of NTS cases increased significantly across all districts. The lowest number of cases was reported in the winter months and was stable from 2007, whereas the highest number was reported in the summer months with a higher tendency of outbreaks. Conclusion: The falling number of salmonellosis cases in 2000⁻2017 in WaM reflects the general trend in Poland and Europe. The decrease of NTS infections in WaM is related to the accession of Poland into the EU.

Using Microsimulation to Estimate the Future Health and Economic Costs of Salmonellosis under Climate Change in Central Queensland, Australia.

BACKGROUND: The incidence of salmonellosis, a costly foodborne disease, is rising in Australia. Salmonellosis increases during high temperatures and rainfall, and future incidence is likely to rise under climate change. Allocating funding to preventative strategies would be best informed by accurate estimates of salmonellosis costs under climate change and by knowing which population subgroups will be most affected. OBJECTIVE: We used microsimulation models to estimate the health and economic costs of salmonellosis in Central Queensland under climate change between 2016 and 2036 to inform preventative strategies. METHODS: We projected the entire population of Central Queensland to 2036 by simulating births, deaths, and migration, and salmonellosis and two resultant conditions, reactive arthritis and postinfectious irritable bowel syndrome. We estimated salmonellosis risks and costs under baseline conditions and under projected climate conditions for Queensland under the A1FI emissions scenario using composite projections from 6 global climate models (warm with reduced rainfall). We estimated the resulting costs based on direct medical expenditures combined with the value of lost quality-adjusted life years (QALYs) based on willingness-to-pay. RESULTS: Estimated costs of salmonellosis between 2016 and 2036 increased from 456.0 QALYs (95% CI: 440.3, 473.1) and AUD29,900,000 million (95% CI: AUD28,900,000, AUD31,600,000), assuming no climate change, to 485.9 QALYs (95% CI: 469.6, 503.5) and AUD31,900,000 (95% CI: AUD30,800,000, AUD33,000,000) under the climate change scenario. CONCLUSION: We applied a microsimulation approach to estimate the costs of salmonellosis and its sequelae in Queensland during 2016-2036 under baseline conditions and according to climate change projections. This novel application of microsimulation models demonstrates the models' potential utility to researchers for examining complex interactions between weather and disease to estimate future costs. https://doi.org/10.1289/EHP1370.

Burden of salmonellosis, campylobacteriosis and listeriosis: a time series analysis, Belgium, 2012 to 2020.

Salmonellosis, campylobacteriosis and listeriosis are food-borne diseases. We estimated and forecasted the number of cases of these three diseases in Belgium from 2012 to 2020, and calculated the corresponding number of disability-adjusted life years (DALYs). The salmonellosis time series was fitted with a Bai and Perron two-breakpoint model, while a dynamic linear model was used for campylobacteriosis and a Poisson autoregressive model for listeriosis. The average monthly number of cases of salmonellosis was 264 (standard deviation (SD): 86) in 2012 and predicted to be 212 (SD: 87) in 2020; campylobacteriosis case numbers were 633 (SD: 81) and 1,081 (SD: 311); listeriosis case numbers were 5 (SD: 2) in 2012 and 6 (SD: 3) in 2014. After applying correction factors, the estimated DALYs for salmonellosis were 102 (95% uncertainty interval (UI): 8-376) in 2012 and predicted to be 82 (95% UI: 6-310) in 2020; campylobacteriosis DALYs were 1,019 (95% UI: 137-3,181) and 1,736 (95% UI: 178-5,874); listeriosis DALYs were 208 (95% UI: 192-226) in 2012 and 252 (95% UI: 200-307) in 2014. New actions are needed to reduce the risk of food-borne infection with Campylobacter spp. because campylobacteriosis incidence may almost double through 2020.

Distinct Salmonella Enteritidis lineages associated with enterocolitis in high-income settings and invasive disease in low-income settings.

An epidemiological paradox surrounds Salmonella enterica serovar Enteritidis. In high-income settings, it has been responsible for an epidemic of poultry-associated, self-limiting enterocolitis, whereas in sub-Saharan Africa it is a major cause of invasive nontyphoidal Salmonella disease, associated with high case fatality. By whole-genome sequence analysis of 675 isolates of S. Enteritidis from 45 countries, we show the existence of a global epidemic clade and two new clades of S. Enteritidis that are geographically restricted to distinct regions of Africa. The African isolates display genomic degradation, a novel prophage repertoire, and an expanded multidrug resistance plasmid. S. Enteritidis is a further example of a Salmonella serotype that displays niche plasticity, with distinct clades that enable it to become a prominent cause of gastroenteritis in association with the industrial production of eggs and of multidrug-resistant, bloodstream-invasive infection in Africa.

Salmonellosis Hospitalizations in the United States: Associated Chronic Conditions, Costs, and Hospital Outcomes, 2011, Trends 2000-2011.

Hospitalized salmonellosis patients with concurrent chronic conditions may be at increased risk for adverse outcomes, increasing the costs associated with hospitalization. Identifying important modifiable risk factors for this predominantly foodborne illness may assist hospitals, physicians, and public health authorities to improve management of these patients. The objectives of this study were to (1) quantify the burden of salmonellosis hospitalizations in the United States, (2) describe hospitalization characteristics among salmonellosis patients with concurrent chronic conditions, and (3) examine the relationships between salmonellosis and comorbidities by four hospital-related outcomes. A retrospective analysis of salmonellosis discharges was conducted using the Agency for Healthcare Research and Quality's Nationwide Inpatient Sample for 2011. A supplemental trend analysis was performed for the period 2000-2011. Hospitalization characteristics were examined using multivariable regression modeling, with a focus on four outcome measures: in-hospital death, total amount billed by hospitals for services, length of stay, and disease severity. In 2011, there were 11,032 total salmonellosis diagnoses; 7496 were listed as the primary diagnosis, with 86 deaths (case-fatality rate = 1.2%). Multivariable regression analyses revealed a greater number of chronic conditions (≥4) among salmonellosis patients was associated with higher mean total amount billed by hospitals for services, longer length of stay, and greater disease severity (p ≤ 0.05). From 2000 to 2011, hospital discharges for salmonellosis increased by 27.2%, and the mean total amount billed by hospitals increased nearly threefold: $9,777 (2000) to $29,690 (2011). Observed increases in hospitalizations indicate the burden of salmonellosis remains substantial in the United States. The positive association between increased number of chronic conditions and the four hospital-related outcomes affirms the need for continual healthcare and public health investments to prevent and control this disease in vulnerable groups.

Economic effects of introducing alternative Salmonella control strategies in Sweden.

The objective of the study was to analyse the economic effects of introducing alternative Salmonella control strategies in Sweden. Current control strategies in Denmark and the Netherlands were used as benchmarks. The true number of human Salmonella cases was estimated by reconstructing the reporting pyramids for the various scenarios. Costs were calculated for expected changes in human morbidity (Salmonella and two of its sequelae), for differences in the control programmes and for changes in cattle morbidity. The net effects (benefits minus costs) were negative in all scenarios (€ -5 to -105 million), implying that it would not be cost-effective to introduce alternative control strategies in Sweden. This result was mainly due to an expected increase in the incidence of Salmonella in humans (6035-57108 reported and unreported new cases/year), with expected additional costs of € 5-55 million. Other increased costs were due to expected higher incidences of sequelae (€ 3-49 million) and a higher cattle morbidity (€ 4-8 million). Benefits in terms of lower control costs amounted to € 4-7 million.

Economic and health impacts associated with a Salmonella Typhimurium drinking water outbreak-Alamosa, CO, 2008.

In 2008, a large Salmonella outbreak caused by contamination of the municipal drinking water supply occurred in Alamosa, Colorado. The objectives of this assessment were to determine the full economic costs associated with the outbreak and the long-term health impacts on the community of Alamosa. We conducted a postal survey of City of Alamosa (2008 population: 8,746) households and businesses, and conducted in-depth interviews with local, state, and nongovernmental agencies, and City of Alamosa healthcare facilities and schools to assess the economic and long-term health impacts of the outbreak. Twenty-one percent of household survey respondents (n = 369/1,732) reported diarrheal illness during the outbreak. Of those, 29% (n = 108) reported experiencing potential long-term health consequences. Most households (n = 699/771, 91%) reported municipal water as their main drinking water source at home before the outbreak; afterwards, only 30% (n = 233) drank unfiltered municipal tap water. The outbreak's estimated total cost to residents and businesses of Alamosa using a Monte Carlo simulation model (10,000 iterations) was approximately $1.5 million dollars (range: $196,677-$6,002,879), and rose to $2.6 million dollars (range: $1,123,471-$7,792,973) with the inclusion of outbreak response costs to local, state and nongovernmental agencies and City of Alamosa healthcare facilities and schools. This investigation documents the significant economic and health impacts associated with waterborne disease outbreaks and highlights the potential for loss of trust in public water systems following such outbreaks.

Epidemiology, disease spectrum and economic burden of non-typhoidal Salmonella infections in Taiwan, 2006-2008.

The purpose of this study was to understand the seasonal, geographical and clinical characteristics of Taiwanese patients hospitalized for non-typhoidal Salmonella (NTS) infections and their economic burden. Hospital data obtained from the Taiwan National Health Insurance (NHI) database between 2006 and 2008 were analysed. Infants had the highest annual incidence of 525 cases/100 000 person-years. Elderly patients aged >70 years had the highest in-hospital mortality rate (2·6%). Most (82·6%) gastroenteritis occurred in children aged <10 years. Septicaemia, pneumonia, arthritis and osteomyelitis occurred mainly in patients aged >50 years. A median medical cost for NTS-associated hospitalizations was higher for patients with septicaemia than for those with gastroenteritis. Seasonal variation of NTS-associated hospitalizations was correlated with temperature in different areas of Taiwan. In summary, infants had a high incidence of NTS-associated hospitalizations. However, the elderly had a higher in-hospital mortality rate and more invasive NTS infections than children.

A Markov model to estimate Salmonella morbidity, mortality, illness duration, and cost.

Approximately 690000-1790000 Salmonella cases, 20000 hospitalizations, and 400 deaths occur in the USA annually, costing approximately $2.6bn. Existing models estimate morbidity, mortality, and cost solely from incidence. They do not estimate illness duration or use time as an independent cost predictor. Existing models may underestimate physician visits, hospitalizations, deaths, and associated costs. We developed a Markov chain Monte Carlo model to estimate illness duration, physician/emergency room visits, inpatient hospitalizations, mortality, and resultant costs for a given Salmonella incidence. Interested parties include society, third-party payers, health providers, federal, state and local governments, businesses, and individual patients and their families. The marginal approach estimates individual disease behavior for every patient, explicitly estimates disease duration and calculates separate time-dependent costs. The aggregate approach is a Markov equivalent of the existing models; it assumes average disease behavior and cost for a given morbidity/mortality. Transition probabilities were drawn from a meta-analysis of 53 Salmonella studies. Both approaches were tested using the 1993 Salmonella typhimurium outbreak in Gideon, Missouri. This protocol can be applied to estimate morbidity, mortality and cost of specific outbreaks, provide better national Salmonella burden estimates, and estimate the benefits of reducing Salmonella risk.

Conceptualising the technical relationship of animal disease surveillance to intervention and mitigation as a basis for economic analysis.

BACKGROUND: Surveillance and intervention are resource-using activities of strategies to mitigate the unwanted effects of disease. Resources are scarce, and allocating them to disease mitigation instead of other uses necessarily involves the loss of alternative sources of benefit to people. For society to obtain the maximum benefits from using resources, the gains from disease mitigation must be compared to the resource costs, guiding decisions made with the objective of achieving the optimal net outcome. DISCUSSION: Economics provides criteria to guide decisions aimed at optimising the net benefits from the use of scarce resources. Assessing the benefits of disease mitigation is no exception. However, the technical complexity of mitigation means that economic evaluation is not straightforward because of the technical relationship of surveillance to intervention. We argue that analysis of the magnitudes and distribution of benefits and costs for any given strategy, and hence the outcome in net terms, requires that mitigation is considered in three conceptually distinct stages. In Stage I, 'sustainment', the mitigation objective is to sustain a free or acceptable status by preventing an increase of a pathogen or eliminating it when it occurs. The role of surveillance is to document that the pathogen remains below a defined threshold, giving early warning of an increase in incidence or other significant changes in risk, and enabling early response. If a pathogen is not contained, the situation needs to be assessed as Stage II, 'investigation'. Here, surveillance obtains critical epidemiological information to decide on the appropriate intervention strategy to reduce or eradicate a disease in Stage III, 'implementation'. Stage III surveillance informs the choice, timing, and scale of interventions and documents the progress of interventions directed at prevalence reduction in the population. SUMMARY: This article originates from a research project to develop a conceptual framework and practical tool for the economic evaluation of surveillance. Exploring the technical relationship between mitigation as a source of economic value and surveillance and intervention as sources of economic cost is crucial. A framework linking the key technical relationships is proposed. Three conceptually distinct stages of mitigation are identified. Avian influenza, salmonella, and foot and mouth disease are presented to illustrate the framework.

Salmonella Typhimurium and Salmonella Enteritidis in England: costs to patients, their families, and primary and community health services of the NHS.

This is the first study comparing societal costs of acute illness with Salmonella Typhimurium (ST) and Salmonella Enteritidis (SE) in the UK. It included the cost and severity of the illness and explored the impact of each Salmonella serovar on the patients, their families, the NHS, and the wider economy. The study ascertained confirmed cases of ST and SE between July and November 2008. The mean costs per case were £1282 (ST) and £993 (SE). The indirect costs associated with the work-time lost by the case, parents, or carers were £409 (ST) and £228 (SE); this difference was statistically significant. The aggregate cost of ST and SE identified using laboratory test results for the UK as a whole was estimated as £6.5 million. Work-time lost and caring activities are cost categories that are not frequently investigated within the infectious intestinal disease literature, although they represent an important societal cost.

Higher hospital costs and lengths of stay associated with quinolone-resistant Salmonella enterica infections in Hong Kong.

OBJECTIVES: The study sought to determine the differences in lengths of stay and medical costs between patients admitted to hospital with non-typhoidal salmonellosis that were either quinolone resistant (QR) or quinolone susceptible (QS). DESIGN: We examined medical records of all patients 1 year of age or older admitted to a Hong Kong hospital between 2003 and 2008 with confirmed salmonellosis diagnosis. Data were collected on length of stay, age, sex, comorbidities, antibiotics and other medication use, diagnostic tests completed, serotype and susceptibility characteristics of isolated and the circumstances of discharge from hospital. We used Cox proportional regression to determine the differences in lengths of stay and quantile regression for differences in hospital costs. RESULTS: Median duration of hospitalization among QR salmonellosis patients was 1 day (33%; 95% CI: 13-47%) longer than those with QS salmonellosis, adjusting for confounders. Adjusted median costs were US $399 (35%) and 75th percentile costs were US $760 (43%) higher in the QR group than those in the QS group, indicating a greater difference among sicker patients. CONCLUSION: The finding of substantially longer stays and higher costs associated with QR indicates that interventions that decrease QR prevalence will lead to significant savings for the health system in the management of hospitalized salmonellosis cases.

Salmonella typhimurium outbreak in a neonatal unit in Turkey.

OBJECTIVE: To analyze an outbreak caused by a multiple resistant strain of S. typhimurium in a newborn unit in Turkey. METHODS: The outbreak occurred during the period 15 to 29 March,2005. A newborn infected with S. typhimurium was defined as a case. Newborns who were hospitalized during the outbreak period with no diagnosis of S. typhimurium infections (n=50) constituted the control group I (CG I). The matched patients of the control group II (CG II) (n=20) were selected from neonates without S. typhimurium infections during the period. RESULTS: Of 22 infants who were affected two died. Cases developed diarrhea (n=20), septicemia (n=5) and meningitis (n=1). The strain was resistant to ampicillin, ceftriaxone, ceftazidime, amikacin, trimethoprim-sulfamethoxasole and chloramphenicol, susceptible to meropenem. All of the infected neonates were treated with meropenem. The surveillance cultures were negative. The outbreak was controlled by appropriate therapy and institution of effective control measures. The cases were more exposed to mechanical ventilation than CG I (p<0.05). The mean additional length of stay in cases was significantly different from CG II (14.9 days vs. 5.1 days, p<0.05). The mean charges was $1588.78 for a case and $506.94 for a control (P<0.05). Accommodation accounted for 44.5% of these extra charges. CONCLUSION: This study increases the understanding of the burden of multidrug-resistant S. typhimurium infection. Nosocomial outbreaks have a major effect on healthcare delivery, costs and outcomes.

Epidemiology of hospital-treated Salmonella infection; data from a national cohort over a ten-year period.

OBJECTIVE: The aim of this study was to describe the clinical and economic burden of hospital admissions related to Salmonella infections amongst the population of Spain over the course of 10 years (1997-2006). METHODS: Data provided by the National Epidemiology Surveillance System for Hospital Data (Conjunto Mínimo Básico de Datos; CMBD) were analysed. This database included information about Salmonella infection-related hospital incidence rates, patient demographics, length of stay, mortality, case-fatality rates and associated costs. RESULTS: During the period 1997-2006, 65,100 infections due to Salmonella were recorded, indicating an annual incidence rate of 16.18 cases/100,000 people/year (95% confidence interval [CI] 16.05-16.30). The average length of hospital stay for patients with Salmonella infection was of 7.6 days (SD 8.9), and the average patient age was 31 years old (SD 29). The mortality rate was 0.23/100,000 people (95% CI 0.22-0.24 per 100,000 people), and the case-fatality rate was 1.40% (95% CI 1.33-1.51%). The incidence rate was significantly higher in those <14 and >65 years old (maximum of 89.12 cases/100,000 people <4 years old; 95% CI 87.80-90.45 cases/100,000). The mortality and case-fatality rates increased significantly with age, reaching 2.05 deaths per 100,000 people (95% CI 1.70-2.37 cases/100,000) or 7.53% (95% CI 6.34-8.73%) in people >85 years old. The total cost of Salmonella infection was 124 million Euros during the study period, with children up to 4 years of age being the most prominent consumers of resources. CONCLUSIONS: Salmonella infection remains an important cause of hospitalization of children up to 4 years old, but the main mortality and case-fatality rates are observed in persons older than 65 years.

An ecological analysis of sociodemographic factors associated with the incidence of salmonellosis, shigellosis, and E. coli O157:H7 infections in US counties.

Identifying county-level sociodemographic and economic factors associated with the incidence of enteric disease may provide new insights concerning the dynamics of community transmission of these diseases as well as opportunities for prevention. We used data from the National Notifiable Diseases Surveillance System, the U.S. Census Bureau, and the Health Resources and Services Administration to conduct an ecological analysis of 26 sociodemographic and economic factors associated with the incidence of salmonellosis, shigellosis, and E. coli O157:H7 infections in US counties for the period 1993 to 2002. Our study indicates that race, ethnicity, place of residence, age, educational attainment, and poverty may affect the risk of acquiring one of these enteric bacterial diseases. The lack of specificity of information regarding salmonellae and shigellae serotypes may have led to less specific associations between community-level determinants and reported incidence of those diseases. Future ecological analyses should use serotype-specific data on incidence, which may be available from laboratory-based surveillance systems.

The effects, costs and benefits of Salmonella control in the Danish table-egg sector.

A public plan for eradicating Salmonella in Danish table-egg production was implemented in 1996. During 2002, the poultry industry took over the responsibility of the programme. The proportion of infected layer flocks was reduced from 13.4% in 1998 to 0.4% in 2006. The public-health impact of the plan has been quite marked. In 1997, 55-65% of the 5015 cases of human salmonellosis were estimated to be associated with eggs. In 2006, these figures were reduced to 1658 and 5-7%, respectively. Based on an assessment of the number of human cases attributable to table eggs, we used probabilistic modelling to estimate the avoided societal costs (health care and lost labour), and compared these with the public costs of control. The probable avoided societal costs during 1998-2002 were estimated to be 23.3 million euros (95% CI 16.3-34.9), and the results showed a continuous decreasing cost-benefit ratio reaching well below 1 in 2002. Further reductions in the primary production based on effective surveillance and control are required to ensure continued success.

The comparative burden of salmonellosis in the European Union member states, associated and candidate countries.

BACKGROUND: Salmonella is an infectious agents causing numerous cases of illness each year, and thereby having significant economic impact. Using returning Swedish travellers we estimated the burden of salmonellosis in different European countries. METHODS: From the Swedish database on notifiable communicable diseases 15,864 cases with travel-associated salmonellosis acquired in Europe from 1997-2003 were retrieved. These cases were compared to a dataset from the same years on 14,171 randomly selected Swedish residents, with a history of recent overnight travel in Europe. Distribution of salmonellosis in returning travellers and the distribution of Salmonella Enteritidis was analysed for different member states in the European Union, associated and candidate countries. The risk of being notified with a salmonella infection after return from each European country/region was calculated, and compared with official reporting data rom these countries. Using Norway as reference country, we could 1) construct comparable incidence estimates and 2) calculate the "under-reporting" in each country compared to Norway. RESULTS: The highest burden of salmonellosis was estimated for Bulgaria (2741/100,000), followed by Turkey with 2344/100,000 and Malta with 2141/100,000. S. Enteritidis is the dominating serotype, 66.9 % of all cases and phage type 4 accounts for 37.5 % of the S. Enteritidis cases. CONCLUSION: Using returning tourists as a sentinel population can provide a useful base for comparison of disease burdens in different countries/regions. Focusing prevention of salmonellosis to prevention of egg and poultry associated S. Enteritidis infection will have a major impact from a public health perspective and will significantly lower the burden of disease in most European countries.

Hospitalizations and deaths due to Salmonella infections, FoodNet, 1996-1999.

Nontyphoidal Salmonella causes a higher proportion of food-related deaths annually than any other bacterial pathogen in the United States. We reviewed 4 years (1996-1999) of population-based active surveillance data on laboratory-confirmed Salmonella infections from the Emerging Infections Program's Foodborne Diseases Active Surveillance Network (FoodNet), to determine the rates of hospitalization and death associated with Salmonella infection. Overall, 22% of infected persons were hospitalized, with the highest rate (47%) among persons aged >60 years. Fifty-eight deaths occurred, for an estimated annual incidence of 0.08 deaths/100,000 population. These deaths accounted for 38% of all deaths reported through FoodNet from 1996 through 1999, and they occurred primarily among adults with serious underlying disease. Although Salmonella infection was seldom listed as a cause of death on hospital charts and death certificates, our chart review suggests that Salmonella infection contributed to these deaths.

Increased burden of illness associated with antimicrobial-resistant Salmonella enterica serotype typhimurium infections.

This study investigated the burden of illness associated with 440 cases of Salmonella enterica serotype Typhimurium infection identified in Canada between December 1999 and November 2000. We categorized case subjects' infections by definitive phage type 104 (DT104) and antimicrobial-resistance patterns. These variables were then investigated as risk factors for hospitalization. Hospitalization was more likely to occur among case subjects whose infections were resistant to at least ampicillin, chloramphenicol and/or kanamycin, streptomycin, sulphamethoxazole, and tetracycline (R-type AK/CSSuT; odds ratio [OR], 2.3; P=.003), compared with case subjects with AK/CSSuT-susceptible infections, and among case subjects with non-DT104 R-type AKSSuT infections (OR, 3.6; P=.005), compared with case subjects with non-DT104 AKSSuT-susceptible infections. In contrast, hospitalization rates did not differ between case subjects with DT104 infections and case subjects with non-DT104 infections or between case subjects with DT104 R-type ACSSuT infections and case subjects with DT104 ACSSuT-susceptible infections. We estimated that 57% of the hospitalizations among AK/CSSuT case subjects and 72% of the hospitalizations among non-DT104 AKSSuT case subjects were attributable to the resistance patterns of the infections.