Travel-associated antimicrobial drug-resistant nontyphoidal Salmonellae, 2004-2009.

To evaluate trends in and risk factors for acquisition of antimicrobial-drug resistant nontyphoidal Salmonella infections, we searched Oregon surveillance data for 2004-2009 for all culture-confirmed cases of salmonellosis. We defined clinically important resistance (CIR) as decreased susceptibility to ampicillin, ceftriaxone, ciprofloxacin, gentamicin, or trimethoprim/sulfamethoxazole. Of 2,153 cases, 2,127 (99%) nontyphoidal Salmonella isolates were obtained from a specific source (e.g., feces, urine, blood, or other normally sterile tissue) and had been tested for drug susceptibility. Among these, 347 (16%) isolates had CIR. The odds of acquiring CIR infection significantly increased each year. Hospitalization was more likely for patients with than without CIR infections. Among patients with isolates that had been tested, we analyzed data from 1,813 (84%) who were interviewed. Travel to eastern or Southeast Asia was associated with increased CIR. Isolates associated with outbreaks were less likely to have CIR. Future surveillance activities should evaluate resistance with respect to international travel.

Associations between host characteristics and antimicrobial resistance of Salmonella typhimurium.

A collection of Salmonella Typhimurium isolates obtained from sporadic salmonellosis cases in humans from Lower Saxony, Germany between June 2008 and May 2010 was used to perform an exploratory risk-factor analysis on antimicrobial resistance (AMR) using comprehensive host information on sociodemographic attributes, medical history, food habits and animal contact. Multivariate resistance profiles of minimum inhibitory concentrations for 13 antimicrobial agents were analysed using a non-parametric approach with multifactorial models adjusted for phage types. Statistically significant associations were observed for consumption of antimicrobial agents, region type and three factors on egg-purchasing behaviour, indicating that besides antimicrobial use the proximity to other community members, health consciousness and other lifestyle-related attributes may play a role in the dissemination of resistances. Furthermore, a statistically significant increase in AMR from the first study year to the second year was observed.

Salmonella gastroenteritis in children (clinical characteristics and antibiotic susceptibility): comparison of the years 1995-2001 and 2002-2008.

We document herein the prevalence and serotype distribution among Salmonella enterica strains isolated from children treated for diarrhea over two seven-year periods spanning 14 years. Four hundred and eight (1.38%) S. enterica cases were isolated among 29,601 diarrheal admissions. Among the Salmonella isolates, 63.7% were serogroup D and 29.9% were serogroup B. Overall, 21.7% of cases were under one year of age, with 2.1% being younger than three months. Bloody diarrhea was found in 18.8% of the cases. The resistance rates were 25.8%, 18.2%, 7.0%, 4.7%, and 0.3%, to ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole, ceftriaxone, and ciprofloxacin, respectively. In conclusion, our study has revealed that the predominance of Salmonella serogroup D continues. The clinical features of our patients were mostly mild, with no deaths or severe complications. While resistance to antimicrobial agents changes constantly, it is important to keep these strains under surveillance in order to formulate policies for the rational use of antimicrobial agents.

Salmonellosis outbreak due to Salmonella enteritidis phage type 14b resistant to nalidixic acid, Austria, September 2010.

We report on a salmonellosis-outbreak due to Salmonella Enteritidis phage type 14b resistant to nalidixic acid (S. Enteritidis PT14b Nx) among residents and employees of a student residence in Austria, September 2010. The outbreak was described and analysed by a retrospective cohort study, and microbiological environmental investigations were conducted to identify the outbreak source(s) and the reservoir of the outbreak strain. A total of 66 persons fulfilled the outbreak case definition including 14 laboratory-confirmed cases. Food specific cohort-analyses by day revealed that consumption of potato salad (RR: 1.65, 95%CI: 1.35­2.01, p=0.001) and a cheese-sausage cold plate (RR: 2.24, 95%CI: 1.29­3.88, p=0.002) on 14 September was associated with being an outbreak case. We hypothesised that cross-contamination with S. Enteritidis PT14b Nx positive eggs had occurred during preparation of the potato salad and cold plate as a result of preparing in parallel egg-containing breaded cutlets on 14 September. A traced laying hen holding in eastern Austria was identified as the sole source of the consumable eggs in the student residence. By applying the legally mandated sampling method for epidemiological-related laying hen farms (one pooled dust sample à 150g, two paired boot swabs cultured separately), the outbreak strain could not be detected. Our findings, that legally required sampling methods for laying hen farms failed to detect the causative pathogen in a laying hen holding, despite an epidemiological link, underline the request stated by the European Food Safety Authority Panel on Biological Hazards for a more sensitive sampling plan in epidemiologically-associated laying hen flocks.

Outbreak of Salmonella Montevideo associated with a dietary food supplement flagged in the Rapid Alert System for Food and Feed (RASFF) in Germany, 2010.

In March 2010 the Rapid Alert System for Food and Feed (RASFF) was used to inform about Salmonella Montevideo in a herbal food supplement, formulated in capsules, distributed under a Dutch label in Germany. Simultaneous to the first RASFF notice, in the last two weeks of March 2010 an unusual number of 15 infections with S. Montevideo was notified within the electronic reporting system for infectious diseases at the Robert Koch Institute. Adult women (median age: 43, range: 1-90 years) were mainly affected. An outbreak was suspected and the food supplement hypothesised to be its vehicle. Cases were notified from six federal states throughout Germany, which required efficient coordination of information and activities. A case-control study (n=55) among adult women showed an association between consumption of the specific food supplement and the disease (odds ratio (OR): 27.5, 95% confidence interval (CI): 3.1-infinity, p-value=0.002). Restricting the case-control study to the period when the outbreak peaked (between 29 March and 11 April 2010) resulted in an OR of 43.5 (95% CI: 4.8-infinity, p-value=0.001). Trace-back of the supplement's main ingredient, hemp seed flour, and subsequent microbiological testing by pulsed-field gel electrophoresis supported its likely role in transmission. This outbreak investigation illustrates that information from RASFF may aid in hypothesis generation in outbreak investigations, though likely late in the outbreak.

Reported foodborne illness and gastroenteritis in Australia: annual report of the OzfoodNet network, 2004.

In 2004, OzFoodNet sites recorded 24,313 notifications of eight potentially foodborne diseases, along with 118 outbreaks of foodborne disease. Overall, reports of both notifications and outbreaks were higher than previous years. The most common sporadic diseases were campylobacteriosis (15,640 cases) and salmonellosis (7842 cases). Reports of sporadic cases of Shiga toxin-producing Escherichia coli were rare with only 46 cases, but there were two small clusters due to serotypes O157/O111 and 086. The 118 foodborne disease outbreaks affected 2,076 persons, of whom 5.6 per cent (116/2,076) were hospitalised and two people died. Foods prepared in restaurants and catering settings caused the most outbreaks and the most common agent was Salmonella Typhimurium. Outbreak investigations during 2004 implicated chicken, foods containing eggs, imported oysters and food handlers infected with norovirus. In addition to foodborne outbreaks, OzFoodNet sites reported 874 outbreaks that were spread from person-to-person affecting 25,363 people. Sites conducted 54 investigations into clusters of Salmonella and other pathogens where a source could not be identified. Surveillance of foodborne diseases continued to improve during 2004, with all jurisdictions contributing to national cluster reports and using analytical studies to investigate outbreaks. Ninety-eight per cent of Salmonella notifications on state and territory surveillance databases recorded complete information about serotype and phage type. Foodborne disease may cost Australia as much as 1.2 billion dollars annually making it vital to intervene to prevent disease.

Evaluation of IS200-PCR and comparison with other molecular markers To trace Salmonella enterica subsp. enterica serotype typhimurium bovine isolates from farm to meat.

A procedure that uses an original molecular marker (IS200-PCR) and that is based on the amplification of DNA with outward-facing primers complementary to each end of IS200 has been evaluated with a collection of 85 Salmonella enterica subsp. enterica serotype Typhimurium isolates. These strains were isolated from a group of 10 cows at different stages: during transportation between the farm and the slaughterhouse, on the slaughter line, from the environment, and from the final product (ground beef). The 85 isolates were characterized by their antibiotic resistance patterns and were compared by IS200-PCR and by use of four other genotypic markers. Those markers included restriction profiles for 16S and 23S rRNA (ribotypes) and amplification profiles obtained by different approaches: random amplified polymorphic DNA analysis, enterobacterial repetitive intergenic consensus PCR, and PCR ribotyping. The results of the IS200-PCR were in accordance with those of other molecular typing methods for this collection of isolates. Five different genotypes were found, which made it possible to refine the hypotheses on transmission obtained from phenotypic results. The genotyping results indicated the massive contamination of the whole group of animals and of the environment by one clonal strain originally recovered from one cow that excreted the strain. On the other hand, a few animals and their environment appeared to be simultaneously contaminated with genetically different strains.

Nationwide outbreak of human salmonellosis in Germany due to contaminated paprika and paprika-powdered potato chips.

Between April and September 1993, a nationwide outbreak of salmonellosis occurred in Germany which was traced to contaminated paprika and paprika-powdered potato chips. Of the estimated 1000 cases, children below 14 years were principally affected. Levels of 0.04-0.45 organisms per gram were found in the snacks. The infective dose was estimated at 4-45 organisms with an attack rate of 1 in 10,000 exposed persons. The unique feature of the outbreak was the variety of serovars involved. S. saintpaul, S. rubislaw and S. javiana were isolated during the same time period from paprika powder, spice mixtures, snacks and patients. Their clonal identity was confirmed by molecular typing methods. Furthermore, monophasic and non-motile strains of rare salmonella O-groups were isolated from both paprika products and patients. This is the largest documented outbreak due to contaminated spices which proved that even extremely low numbers of salmonellae adapted to the dry state were able to cause illness.

An outbreak of Salmonella enteritidis infection at a fast-food restaurant: implications for foodhandler-associated transmission.

An outbreak of Salmonella enteritidis infection occurred in patrons and employees of a fast-food restaurant. Transmission took place over a 9-day period. A single employee (employee A) was identified who had onset of gastrointestinal illness 1 day before the first reported patron exposures and had S. enteritidis isolated from stool. A case-control study of 37 ill and 20 healthy patrons who ate during shifts worked by employee A demonstrated that curly-fried potatoes and ice (odds ratio [OR], 6.8; 95% confidence interval [CI], 1.5-33.7; P = .007), both food items handled bare-handed by employee A, were associated with illness. Employees who worked two or more shifts with employee A were more likely to be infected than those who did not work with employee A (OR, 4.4; CI, 1.0-19.5; P = .03). Foodhandlers who subsequently became infected apparently contaminated multiple food items with additional transmission to patrons. This outbreak illustrates the potential for foodhandlers in a fast-food restaurant setting who are infected with Salmonella to be a source of transmission.

A national outbreak of salmonellosis from yeast flavoured products.

A national outbreak of salmonellosis caused by a rare serotype occurred between July and November 1989. A total of 40 cases of Salmonella manchester infection were identified by the PHLS Division of Enteric Pathogens with a further 7 cases reported from Scotland. The median age of those affected was one year. All strains from the outbreak carried a 70mDal plasmid with a distinctive restriction endonuclease. A statistical association was found between infection and consumption of nationally distributed savoury corn snacks. Samples of autolysed yeast powder and flavourings used in the manufacture of many processed foods were also found to be positive for S. manchester.

Management of institutional outbreaks of Salmonella gastroenteritis.

The number of reports of outbreaks of salmonella gastroenteritis in hospitals has decreased since 1984 but the number of outbreaks in institutions such as old peoples' homes have increased during 1988. Foods, particularly chickens, remain a source of salmonellae and particular attention has to be paid to training and practices in food preparation areas. Staff who are convalescent are very unlikely to be sources of salmonella and do not need to be excluded unless they handle food that receives no further cooking. Outbreaks that do occur can usually be controlled by patient isolation and good control-of-infection measures and an effective Major Outbreak Control Plan is necessary. In some large old hospitals cross infection outbreaks may continue despite good control-of-infection measures. Antibiotics have been contraindicated in the treatment of salmonella gastroenteritis, but the new 4-quinolone antibiotics have demonstrated potential. Ciprofloxacin was used successfully in two outbreaks of salmonella gastroenteritis at a dose of 500 mg bd orally for seven days. Relapses did not occur and resistance did not develop. Ciprofloxacin should be considered as a therapeutic adjunct to control of infection measures in cross infection outbreaks in these situations.

An outbreak of Salmonella saint-paul infection associated with beansprouts.

In March 1988, there was an outbreak of infection by a strain of Salmonella saint-paul with a distinctive antigenic marker. A total of 143 reports were received between 1 March and 7 June. Preliminary investigations suggested that raw beansprouts were a possible source of infection and a case-control study confirmed the association. S. saint-paul of the epidemic type was isolated from samples of beansprouts on retail sale in different cities in the United Kingdom and from mung bean seeds on the premises of the producer who was most strongly associated with cases. In addition, Salmonella virchow PT34 was isolated from samples of raw beansprouts and was subsequently associated with seven cases of infection. Four other serotypes of salmonella were also isolated from beansprouts. On 8 April the public were advised to boil beansprouts for 15 seconds before consumption, and the premises of the one producer associated with many cases were closed. As a result of these actions there was a significant decrease in the number of infections with S. saint-paul.