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Escherichia coli O157:H7 infections in Wisconsin, 1992-1999
Abstract
Escherichia coli O157:H7 infection became a reportable condition in Wisconsin on April 1, 2000; previously cases were voluntarily reported by physicians and laboratories. During 1992 through 1999, 1333 cases of E. coli O157:H7 infection occurred in Wisconsin residents and were reported to the Wisconsin Division of Public Health. During this interval, the highest age-specific mean annual incidence, 13.2 cases per 100,000 population, occurred in persons 3 to 5 years old. Only 28% of patients with reported cases identified bloody diarrhea among their signs and symptoms. Of reported cases, 17% (231/1333) were involved in the eight outbreaks investigated during this interval. Among case patient identifiable risk exposures, farm related (13.4%), recreational water related (8.1%), and unpasteurized milk/dairy product (7.0%) exposures were the most frequently noted. Relatively few infections involved raw/undercooked ground beef consumption (5.8%). Recent use of pulsed-field gel electrophoresis has facilitated linkage of sporadically reported cases into recognized outbreaks. E. coli O157:H7 infections frequently occur in Wisconsin; acquisition of these infections in a wide variety of settings poses important challenges to their prevention and control.
... The highest incidence of HUS caused by E. coli O157 infection occurred in children under 6 years of age (30)(31)(32). We chose this target age group, children 2 to 5 years old, to study the safety and immunogenicity of our O157-rEPA conjugate. ...
... Reference serum (ECO 161) was from the phase I study in adults injected with the OSP-rEPA. age-related incidence rate of E. coli O157 (1,2,30,31,32). Adults also responded with about 4-fold higher anti-LPS IgG than children at all time intervals. However, at 26 weeks, the level of antibodies in children remained about 12 times higher than the adults' preimmune level, implying that the children after vaccination had elevated immunity to E. coli O157. ...
Pediatric immunization has been the most effective measure to prevent and reduce the burden of infectious diseases in children. The recent inclusion of pneumococcal and meningococcal polysaccharide conjugates in infant immunization further reinforces their importance. Currently there is no human vaccine against enterohemorrhagic Escherichia coli (EHEC) infections. This review focuses on the human EHEC vaccine that has been studied clinically, in particular, the polysaccharide conjugate against E. coli O 157. The surface polysaccharide antigen, O-specific polysaccharide, was linked to rEPA, recombinant exotoxin A of Pseudomonas aeruginosa . In adults and children 2 to 5 years old, O157-rEPA conjugates, shown to be safe, induced high levels of antilipopolysaccharide immunoglobulin G with bactericidal activities against E. coli O157, a functional bioassay that mimics the killing of inoculum in vivo. A similar construct using the B subunit of Shiga toxin (Stx) 1 as the carrier protein elicited both bactericidal and toxin-neutralizing antibodies in mice.
So far there is no clinical study of Stx-based human vaccine. Passive immunization of Stx-specific antibodies with humanized, chimeric, or human monoclonal antibodies, produced in transgenic mice, showed promising data in animal models and offered high prospects. Demonstrations of their safety and effectiveness in treating hemolytic-uremic syndrome or patients with EHEC infections are under way, and results are much anticipated.
For future development, other virulence factors such as the nontoxic Stx B subunit or intimin should be included, either as carrier protein in conjugates or as independent components. The additional antigens from O157 may provide broader coverage to non-O157 Stx-producing E. coli and facilitate both preventive and therapeutic treatment.
... At FoodNet sites in 1999, 35.3% of reported cases occurred in 1-to 10-year-olds, 17.6% of cases occurred in 10-to 20-year-olds, and 14.1% of cases occurred in persons older than 60 (CDC 2000b). Other studies have also found a high incidence in children Proctor and Davis 2000). ...
... Sporadic cases account for the majority of reported cases in a given year and therefore may be more representative of persons with E. coli O157:H7 infection. For example, 75% of reported cases in Oregon during 1991 to 1997 and 83% of reported cases in Wisconsin during 1992 to 1999 were sporadic (OCD 1998;Proctor and Davis 2000). ...
As the demand for reliable and safe water supplies increases, both water quality and available quantity are being challenged by population growth and climate change. Greywater reuse is becoming a common practice worldwide; however, in remote locations of limited water supply, such as those encountered in military installations, it is desirable to expand its classification to include dishwashing water to maximize the conservation of fresh water. Given that no standards for dishwashing greywater reuse by the military are currently available, the current study determined a specific set of water quality standards for dishwater recycling systems for U.S. military field operations. A tentative water reuse standard for dishwashing water was developed based on federal and state regulations and guidelines for non-potable water, and the developed standard was cross-evaluated by monitoring water quality data from a full-scale dishwashing water recycling system using an innovative electrocoagulation and ultrafiltration process. Quantitative microbial risk assessment (QMRA) was also performed based on exposure scenarios derived from literature data. As a result, a specific set of dishwashing water reuse standards for field analysis (simple, but accurate) was finalized as follows: turbidity (<1NTU), Escherichia coli (<50cfumL(-1)), and pH (6-9). UV254 was recommended as a surrogate for organic contaminants (e.g., BOD5), but requires further calibration steps for validation. The developed specific water standard is the first for dishwashing water reuse and will be expected to ensure that water quality is safe for field operations, but not so stringent that design complexity, cost, and operational and maintenance requirements will not be feasible for field use. In addition the parameters can be monitored using simple equipment in a field setting with only modest training requirements and real-time or rapid sample turn-around. This standard may prove useful in future development of civilian guidelines.
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... Enteric infection outbreaks have been reported involving consumption of raw milk and products made from raw milk (De Buyser et al., 2001;Gillespie et al., 2003;Keene et al., 1997;Proctor and Davis, 2000). Proctor and Davis (2000) reported that between 1992 and 1999, 7% of E. coli infections reported in Wisconsin was linked to the consumption of raw milk. ...
... Enteric infection outbreaks have been reported involving consumption of raw milk and products made from raw milk (De Buyser et al., 2001;Gillespie et al., 2003;Keene et al., 1997;Proctor and Davis, 2000). Proctor and Davis (2000) reported that between 1992 and 1999, 7% of E. coli infections reported in Wisconsin was linked to the consumption of raw milk. Gillespie et al. (2003) showed that between 1992 and 2000, 52% of foodborne outbreaks in England and Wales were attributed to consumption of raw milk. ...
The dairy farm environment and animals on the farm serve as important reservoirs of pathogenic and commensal bacteria that could potentially gain access to milk in the bulk tank via several pathways. Pathogenic gram-negative bacteria can gain access to bulk tank milk from infected mammary glands, contaminated udders and milking machines, and/or from the dairy farm environment. Contaminated raw milk when consumed by humans or fed to animals on the farm can result in gastroenteric infections in humans and animals and also provide an opportunity for organisms to colonize the farm environment. This scenario becomes much more complicated when pathogenic bacteria such as Salmonella, Shiga toxin-producing Escherichia coli, and commensal gram-negative enteric bacteria encode for antimicrobial resistance determinants. In recent years, the role of commensal bacteria as reservoirs of genetic determinants for antimicrobial resistance has come under closer scrutiny. Commensal bacteria in bulk tank milk can be a significant reservoir of antimicrobial determinants. Raw milk consumption can result in exposure to antimicrobial-resistant commensal gram-negative bacteria. This paper examines the prevalence and role of commensal gram-negative enteric bacteria in bulk tank milk and their public health significance.
... The spices have been used for food preservation since prehistoric days because they have antiseptic and disinfectant properties [9,10]. The spices like clove, oregano, thyme, cinnamom and cumin possess certain antibacterial and antifungal activities against food spoilage organisms like Bacillus subtilis, Pseudomomas fluorescens, ...
Saccharomyces cerevisiae is commonly known yeast for its role as "baker's yeast", but recently, some strains of it have been reported as an emerging food born pathogen. It can lead to spread of infections in specific organs like lung and blood, especially in immune-compromised patients. The main cause is the multi-drug resistance of the species to the drugs including amphotericin B and azole derivatives. To control the antibiotic resistance of this food born pathogen, different ways have to be explored. There has been a surge in interest in evaluating plants with antibacterial and antifungal activity against variety of common contaminating agents. The biologically active compounds found in various plant parts in the form of spices have evolved the interest of scientists working in this field. The spices like clove, oregano, thyme, cinnamom and cumin possess certain antibacterial and antifungal activities against organisms. This study is conducted to investigate the antimicrobial activity of the extracts of five common spices-black pepper (Piper nigrum), black cardamom (Amomum subulatum), cloves (Syzygium aromaticum), red chilli (Capsicum annum), and cinnamon (Cinnamom umverum) against Saccharomyces cerevisiae. Out of the five extracts, Piper nigrum showed maximum zone of inhibition of 22 mm diameter against the strain of Saccharomyces cerevisiae. So, the black pepper extract can be considered as one of the best antimicrobial agent and an alternative against the diseases caused by Saccharomyces cerevisiae. This can be applied further in various medicines and food products to prevent the diseases caused by this yeast.
... Hence, out of 322 examined samples identified positive as E. coli by NSF, only 0.6% of the total were identified as E. coli O157: Our findings were concordant with the above studies, whereas other researchers have reported differently; for instance in Lagos, Nigeria, researchers recovered E. coli O157:H7 from 6% of diarrhoea sufferers [17]. In another investigation in Wisconsin during 1992-9 the occurrence of 1333 infections as a result of E. coli O157:H7 was documented [18]. During an outbreak of diarrhoea in northern Palestine in 1992 Adwan et al. examined 250 collected stool samples and reported 124 positive cases of E. coli O157 (about 50%) [3]. ...
Escherichia coli O157:H7 has been implicated in diarrhoea, dysentery, haemorrhagic coli-tis and uraemic haemolytic syndrome but is not routinely cultured in laboratories. We tested 322 samples from children referred with diarrhoea to a clinic in Zahedan, Islamic Republic of Iran. There were 21 sorbitol-negative E. coli isolated; serotyping revealed 4 strains positive for O157, out of which only 2 strains were identified as E. coli O157:H7. Both cases were boys, aged 1.5 and 4 years respectively. Antibiotic sensitivity testing found the strains were sensitive for amikacin, gentamicin, nitrofurantoin and tobramycin and resistant to chloramphenicol, cefalexin, cefalothin and co-trimoxazole. Fréquence d'Escherichia coli O157:H7 chez les enfants souffrant de diarrhée à Zahedan en République islamique d'Iran RÉSUMÉ La bactérie Escherichia coli O157:H7 est responsable de diarrhée, de dysenterie, de colite hémorragique et de syndrome hémolytique et urémique, mais elle n'est pas systématiquement mise en culture dans les laboratoires. Nous avons testé 322 échantillons provenant d'enfants souffrant de diarrhée et adressés à un centre de consultations de Zahedan (République islamique d'Iran). Nous avons ainsi isolé 21 E. coli sorbitol-négatives ; le typage sérologique a révélé 4 souches positives pour le sérogroupe O157, dont 2 seulement ont été identifiées comme étant E. coli O157:H7. Les deux cas étaient des garçons âgés respectivement de 1,5 et 4 ans. Le test de sensibilité aux antibiotiques a permis de déterminer que les souches étaient sensibles à l'amikacine, à la gentamicine, à la nitrofurantoïne et à la tobramycine, et résistantes au chloramphénicol, à la céfalexine, à la céfalotine et au co-trimoxazole.
... These results are significant regarding the emergence of E. coli 0157 and S. enterica serovar enteridis as foodborne pathogens that have significant impact on the food industry. Moreover, these bacteria present various undesirable attributes of virulence that in combination make them some of the most serious threats for food safety (Proctor and Davis, 2000). Effect of clove extract on the production of vero-toxin by enterohemorrhagic E. coli (EHEC) 0157:H7 was investigated by Sakagami et al. (2000) where verotoxin production was inhibited by garlic extract (0.5% w/v). ...
There has been constant an increasing the search alternative and efficient compounds for food conservation, aiming a partial or total replacement of antimicrobial chemical additives. Spices offer a promising alternative for food safety. Inhibitory activity of spices and derivatives on the growth of bacteria, yeasts, fungi and microbial toxins synthesis has been well reported, so they could be used in food conservation as main or as adjuvant antimicrobial compounds in order to assure the production of microbiologically stable foods.
... Direct or indirect contact with dairy cattle during farm visits were associated with cases of disease (39,132,233). Retrospective analysis of case records in Wisconsin from 1992-1999 indicated that ground beef (5.8%) was associated with fewer infections than farm related exposure (13.4%), recreational water exposure (8.1%) or consumption of unpasteurized milk/dairy products (7.0%) (172). It is evident that STEC O157:H7 colonizing dairy cattle have multiple opportunities to infect humans. ...
... Milk contamination occurs usually during milking, although it is possible during storage and transportation. Pathogenic microorganisms such as Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes in raw milk have been responsible for several outbreaks of foodborne illnesses (Omiccioli, Amagliani, Brandi, & Magnani, 2009;Proctor & Davis, 2000). Even though pasteurization is the established method of ensuring the safety of milk, foodborne pathogens have also been reported from the pasteurized milk (Ackers et al., 2000;Mazumdar, Hartmann, Kämpfer, & Keusgen, 2007;Olsen et al., 2004). ...
The objective of this study was to investigate the antibacterial effect of caffeine on the behavior and changes in cell morphology of E. coli O157:H7 in a liquid medium and in skim milk. The inhibitory effect of caffeine at different concentrations was determined by inoculating E. coli O157:H7 in laboratory medium and skim milk samples. Samples were incubated at 37ºC for 48 h, and E. coli O157:H7 population was enumerated. Our results showed that caffeine significantly (P < 0.05) inhibited the growth of E. coli O157:H7 in laboratory medium and milk samples. A greater than 3.0 log CFU ml⁻¹ inhibition was observed in milk containing 5.0 g/L caffeine within 12 h of incubation. Moreover, using flow cytometry, marked changes in the morphology of E. coli O157:H7 were also observed. Caffeine has potential as an antimicrobial agent and could be used as an effective natural additive to improve the safety of food products.
... These results are significant regarding the emergence of E. coli 0157 and S. enterica serovar enteridis as foodborne pathogens that have significant impact on the food industry. Moreover, these bacteria present various undesirable attributes of virulence that in combination make them some of the most serious threats for food safety (Proctor and Davis, 2000). Effect of clove extract on the production of vero-toxin by enterohemorrhagic E. coli (EHEC) 0157:H7 was investigated by Sakagami et al. (2000) where verotoxin production was inhibited by garlic extract (0.5% w/v). ...
There has been constant an increasing the search alternative and efficient compounds for food conservation, aiming a pa rtial or total replacement of antimicrobial chemical additives. Spices offer a p romising alternative for food safety. Inhibitory activity of spices and d erivatives on the growth o f bacteria, yeasts, fungi and microbial t oxins synthesis has been well reported, so they could be used in food conservation as main or as adjuvant antimicrobial compounds in order to assure the production of microbiologically stable foods.
... Since its identification as human pathogen in 1982, Escherichia coli O157:H7 has being a pathogen of major concern due to its ability to cause from relatively mild to fatal illnesses, including bloody diarrhea, hemorrhagic colitis, hemolytic uremic syndrome and thrombotic thrombocytopenic purpura (Ferens and Hovde, 2011). Since the gastrointestinal tract of ruminants, mainly cattle, is the natural reservoir of E. coli O157:H7 (Mainil and Daube, 2005), the consumption of raw milk and dairy products has been associated with several foodborne illnesses caused by this pathogen (CDCP, 2007(CDCP, , 2008CDSC, 1998CDSC, , 1999Guh et al., 2010;Honish et al., 2005;Morgan et al., 1993;Proctor and Davis, 2000;Rangel et al., 2005;Upton and Coia, 1994;Watanabe et al., 1999). Considering its low infectious dose (1 to 100 cells) (Teunis et al., 2004) and its ability to survive in various adverse environmental conditions (Caro et al., 2011;Conedera et al., 2004;Dinu and Bach, 2011;House et al., 2009;Usajewicz and Nalepa, 2006;Vernozy-Rozand et al., 2005), E. coli O157:H7 requires very sensitive and reliable detection and enumeration methods for both stressed and healthy cells in foods, even in presence of outnumbering competing bacteria. ...
A mid-log phase broth culture of Escherichia (E.) coli O157:H7 381 (final concentration 10(4)cfu/mL) was monitored by conventional liquid- and solid-based enumeration techniques combined with PCR while it was subjected to thermal stress in gradually more complex systems (i.e., Tryptone Soya Broth, pasteurized milk and during lab-scale productions of a pasta filata fior di latte cheese obtained from raw or pasteurized milk). Our results highlighted: i) the incapability of the selective medium, ii) the effectiveness of the thin agar layer-PCR method, and iii) the effectiveness of the most probable number (MPN)-PCR method (in comparison with both plating-based methods) in recovering and selectively counting viable and stressed or injured E. coli O157:H7. Moreover, MPN-PCR was superior to both plating-based methods in terms of speed and easiness to get results. The thermal stresses herein applied (heating at 55°C for 5 and 8min) were less effective on the pasteurized milk than on the Tryptone Soya Broth and the pathogen was more protected in the raw milk-based matrices than in the pasteurized ones. Moreover, given the contamination level (10(4)cfu/mL of milk) of the strain, the temperature/time of stretching and the hardening and brining conditions herein used, the complete inactivation of the pathogen is not achievable.
... Raw (unpasteurized) milk is an important vehicle of transmission of pathogenic microorganisms such as Salmonella spp., Escherichia coli O157 and Listeria monocytogenes. Several outbreaks of food-borne illnesses following consumption of raw milk and milkbased products caused by Shiga toxin-producing E. coli (STEC; Proctor and Davis, 2000), Salmonella spp. (Reed and Grivetti, 2000; CDC, 2003; Mazurek et al., 2004) and L. monocytogenes (CDC, 2001) have been reported in recent years, indicating the importance of this problem in safeguarding public health. ...
Intoxications and infections caused by food-borne pathogens represent an increasing public health problem, and diagnostic tests in multiplex format are needed for the rapid identification of food contaminations caused by more than one microbial species. We have developed a multiple PCR-based platform for the simultaneous detection of the widespread milk-associated pathogens Salmonella spp., Listeria monocytogenes and Escherichia coli O157. The assay combines an enrichment step in a medium properly formulated for the simultaneous growth of target pathogens, a DNA isolation method, and a multiplex Real-Time PCR detection system based either on dual-labelled probes (mRT-PCR), or on melting curve analysis (mHRM). The second, producing a distinct peak for each amplification product, allows the qualitative assessment of pathogen presence. Moreover, the internal amplification control (IAC) included in the reaction, ensuring the reliability of results, complies with quality management programmes. Inclusivity and exclusivity were 100% each, with a detection limit of 1 CFU for each pathogen in a total of five 25 ml-aliquots of raw milk, and a duration of two working days. The assay represents an alternative approach for the qualitative detection of the cited bacterial species, suitable for a relatively inexpensive screening of several milk samples, reducing the turnaround time and the workload.
... Our findings were concordant with the above studies, whereas other researchers have reported differently; for instance in Lagos, Nigeria, researchers recovered E. coli O157:H7 from 6% of diarrhoea suffer- ers [17] . In another investigation in Wisconsin during 1992–9 the occurrence of 1333 infections as a result of E. coli O157:H7 was documented [18]. During an outbreak of diarrhoea in northern Palestine in 1992 Adwan et al. examined 250 collected stool samples and reported 124 positive cases of E. coli O157 (about 50%) [3]. ...
Escherichia coli O157:H7 has been implicated in diarrhoea, dysentery, haemorrhagic colitis and uraemic haemolytic syndrome but is not routinely cultured in laboratories. We tested 322 samples from children referred with diarrhoea to a clinic in Zahedan, Islamic Republic of Iran. There were 21 sorbitol-negative E. coli isolated; serotyping revealed 4 strains positive for O157, out of which only 2 strains were identified as E. coli O157:H7. Both cases were boys, aged 1.5 and 4 years respectively. Antibiotic sensitivity testing found the strains were sensitive for amikacin, gentamicin, nitrofurantoin and tobramycin and resistant to chloramphenicol, cefalexin, cefalothin and co-trimoxazole.
... It is well known that humans can catch illness as a consequence of the exposure to risk factors occurring in water (Eliassen & Cummings 1948;Craun 1986;Parsonnet et al. 1989;Proctor et al. 1998;Hoxie et al. 1998;Proctor & Davis 2000;Hunter & Syed 2001;Hunter et al. 2003;Naumova et al. 2003;Fong & Lipp 2005;WHO 2005). ...
Water related disease outbreak (WRDO) statistics in Italy from 1998 to 2005 have been discussed in this paper. The true incidence of WRDO is not reflected in the National Surveillance System (NSS), although this study has provided information on pathogens associated to different water sources, incidence in Regions and inadequacy of regulations. 192 outbreaks and 2546 cases of WRD were reported to the NSS, an average of 318 cases per year. Cases were associated to shellfish (58.79%), drinking water (39.94%) and agricultural products (1.25%). WRDs have been detected in 76% of Regions: central and southern Regions showed lower percentage of cases (35.4%) due to under-reporting. Most of WRD cases in the North were related to drinking water; WRDs in marine coastal Regions were mostly related to shellfish. 49% of Districts (Province) notified WRDs, including only 101 Municipalities. Pathogenic microorganisms were identified in a few cases from clinical investigations. They included enteric viruses, Norwalk viruses, Salmonella, Shigella, Giardia and Campylobacter. There is the need to improve the existing NSS in relation to WRDs. An adequate WRDs Surveillance System should be based on connection between health and environmental authorities, priority pathogens and critical areas identification, response capability and contingency plans.
... products. E. coli O157:H7 has been reported to cause food poisoning outbreaks involving the consumption of milk and dairy products (20,21,26). Salmonellae continue to be a major concern for the dairy industry, because these bacteria have caused recent outbreaks of illness and have been isolated from various dairy products in the marketplace (9). ...
Salmonella enterica serovar Enteritidis PT4 and PT6 are associated with food poisoning outbreaks and are often found in food only in low concentrations. In this study a reproducible laboratory-scale procedure for preparation of mayonnaise is presented. The mayonnaise that simulates a naturally low-level contaminated product can be used for validation of new methods and is also suitable to study the behavior of low numbers of food pathogenic spoilage microorganisms in a food environment. During processing, liquid egg was artificially contaminated with low levels of S. enterica serovar Enteritidis that resulted in levels of 1 to 3 log10 CFU/g in the final mayonnaise. Cells of S. enterica serovar Enteritidis had increased stability in the mayonnaise when they were subjected to low pH in two stages, first to pH 5.8 and afterward to pH 4.5 before addition to the mayonnaise. The pH of the mayonnaise was between 4.2 to 4.5 and remained stable over the storage period. Low-level S. enterica serovar Enteritidis remained stable in artificially contaminated mayonnaise for 4 weeks at 4 degrees C.
... products. E. coli O157:H7 has been reported to cause food poisoning outbreaks involving the consumption of milk and dairy products (20,21,26). Salmonellae continue to be a major concern for the dairy industry, because these bacteria have caused recent outbreaks of illness and have been isolated from various dairy products in the marketplace (9). ...
The production of cheese with incurred low levels of pathogenic microorganisms stressed by the production process was the aim of the study. A standard protocol for the preparation of artificially contaminated soft cheese on a laboratory scale was developed. Milk for cheese preparation was artificially contaminated with pathogenic target microorganisms at low levels, between 1 and 10 CFU/ml. Two strains of Escherichia coli OI157:H7, two strains of Listeria monocytogenes, and three Salmonella spp. (Salmonella enterica serovars Typhimurium, Enteritidis, and Dublin) were investigated. The food pathogens in the cheese were exposed to the entire production process. All three microorganism species survived the cheese production process and were detected in the final product at concentrations between 1 and 50 CFU/g. The cheese produced contains target microorganisms that have been exposed to curd formation, drainage, setting, and ripening. This cheese can be used to validate microbiological methods or to examine the target microorganisms in a natural food environment at low concentrations. It represents an alternative to artificial contamination of cheese by adding target microorganisms to a final cheese product.
Shiga toxin (Stx)‐producing Escherichia coli (STEC) is a food‐borne pathogen that can lead to complications such as hemorrhagic colitis and hemolytic‐uremic syndrome (HUS), serious sequelae. In the United States, the most common E. coli serotype causing outbreaks is O157:H7, although non‐O157 serotypes also cause the same disease, but in much fewer cases. The highest incidence rate is among children of preschool age ( 1 , 2 ).
Background:
Shiga-toxin E. coli infections remain a public health concern because of the severity of the gastrointestinal illness and associated complications. Transmission pathways are typically elucidated from outbreaks, with foodborne transmission the primary source. However, most STEC cases are sporadic. This systematic review aimed to identify the most common pathways for sporadic STEC transmission and quantify their importance.
Methods:
We systematically reviewed epidemiological studies of sporadic (non-outbreak) STEC cases that investigated potential risk factors. Searches were run in Medline, EMBASE, and Scopus. Included studies needed to confirm STEC infection and investigate ≥20 cases.
Results:
31 studies were included, of which 25 were case-control or case-case studies. 62.5% found consumption of undercooked/raw meat associated with STEC infection while 70.4% found contact with animals or their environment a risk factor. Random-effects meta-analysis provided pooled odds ratios and population attributable fraction (PAF). The PAF was 19% for undercooked/raw meat, followed by person to person transmission at 15%. Contact with animals and visiting farm environments had PAFs of 14% and 12% respectively.
Conclusions:
Out of potential sources for STEC exposure, undercooked meat and contact with animals and their environment were the most frequently found transmission routes. Decreasing the chances of acquiring the bacteria by these methods would additionally cut down on the other major transmission route, person-to-person spread.
The antimicrobial activity of the aqueous and ethanol extracts of nine Nigerian spices (Xylopia aethiopica, Myristia fragran, Aframomum sceptum, Garcina cola, Zingiber official, Piper guanine, Allium cepa, Vanilla fragran and Opium gratissimum) against Staphylococcus aureus, Klebsiella pneumoniae, Proteus vulgaris and Streptococcus faecalis was evaluated by determining the minimum inhibitory concentrations (MIC) of the extracts. By and large, all the extracts possessed antimicrobial properties with the MIC of the extracts in the range of 5 mg/ml to 22 mg/.ml. The ethanol extract of V. fragran (MIC=5 mg/ml ─ 10 mg/ml) was the most potent of all extracts while the least potent of the extract was M. fragran (MIC=18 mg/ml ─ 22 mg/ml).
The growth and survival of Escherichia coli 0157 and Salmonella enterica serovar Enteritidis were studied in the presence of garlic, ginger, mustard and cloves. Experiments in broth model systems supplemented with 0.25–1% of garlic and clove showed bacteriostatic and bacteriocidal activities towards both microorganisms. Clove was the most effective antimicrobial followed by garlic. Mustard and ginger had only little bacteriostatic activity. E. coli 0157 was more sensitive than S. enterica serovar Enteritidis against all spices tested except mustard. Garlic was selected from the sensorial point of view as a suitable additive for mayonnaise. The efficacy of garlic in artificially contaminated mayonnaise with 105 CFU/g S. enterica serovar Enteritidis was tested. Garlic (1%) reduced the viable cells of S. enterica serovar Enteritidis in mayonnaise by a factor of 10.
Previous studies of bacterial enteric infections have suggested a disproportionate disease burden for children younger than 5 years of age.
This study describes population-based incidence of culture-confirmed infections with 6 bacterial enteric pathogens in children younger than 5 years of age in the Foodborne Diseases Active Surveillance Network (FoodNet), 1996-1998.
Cases were ascertained through active laboratory-based surveillance in Minnesota, Oregon and selected counties in California, Connecticut, Georgia, Maryland and New York.
Twenty-one percent (5218 of 24,358) of infections were in children younger than 5 years of age, but this age group made up only 7% of the total person-years of observation. Among those younger than 5 years of age, the incidence (cases per 100,000 person-years) for each pathogen was: Salmonella, 55.3; Campylobacter, 43.4; Shigella, 32.7; E. coli O157, 10.3; Yersinia enterocolitica, 7.1; Listeria monocytogenes, 0.7. Incidence varied widely among the 7 FoodNet sites.
This study confirmed a disproportionate disease burden in young children. Investigation of risk factors specific to this age group and review and enhancement of current prevention and control strategies for children younger than 5 years of age may reduce illness.
A 2-part study was conducted to determine the risk of exposure to human pathogens from raw milk. The first part of the study focused on determining raw milk consumption habits of dairy producers. A total of 248 dairy producers from 16 counties in Pennsylvania were surveyed. Overall, 105 (42.3%) of the 248 dairy producers consumed raw milk and 170 (68.5%) of the 248 dairy producers were aware of foodborne pathogens in raw milk. Dairy producers who were not aware of foodborne pathogens in raw milk were 2-fold more likely to consume raw milk compared with dairy producers who were aware of foodborne pathogens. The majority of dairy producers who consumed raw milk indicated that taste (72%) and convenience (60%) were the primary factors for consuming raw milk. Dairy producers who resided on the dairy farm were nearly 3-fold more likely to consume raw milk compared with those who lived elsewhere. In the second part of the study, bulk tank milk from the 248 participating dairy herds was examined for foodborne pathogens. Campylobacter jejuni (2%), Shiga toxin-producing Escherichia coli (2.4%), Listeria monocytogenes (2.8%), Salmonella (6%), and Yersinia enterocolitica (1.2%) were detected in the milk samples. Salmonella isolates were identified as S. enterica serotype Typhimurium (n = 10) and S. enterica serotype Newport (n = 5). Of the 248 bulk tank milk samples, 32 (13%) contained > or = 1 species of bacterial pathogens. The findings of the study could assist in developing farm community-based educational programs on the risks of consuming raw milk.
While the US Environmental Protection Agency's (EPA) Beaches Environmental Assessment and Coastal Health (BEACH) Act requires coastal and Great Lakes' states to implement plans for monitoring bacterial contamination of recreational beach water, exactly how this monitoring should occur has not been regulated. This study examined differences in concentration of Escherichia coli in water collected from different depths and from different horizontal locations across the beach. E. coli concentrations were significantly different (p<0.05), when water from different depths was compared. Sampling water at depths of 30, 60, and 120 cm resulted in significantly lower E. coli concentrations as depth increased. Had the State of Wisconsin chosen to collect beach water monitoring samples at a shallower or deeper depth, numbers of beach closures and the potential risk to public health would have changed substantially. These data imply that a revised and standardized protocol for monitoring beach water should be adopted by all states of a monitoring region to better compare microbial contamination of beaches and protect public health.
Runoff from agricultural land into watercourses may transport and deposit animal-derived waste contaminated with Escherichia coli O157:H7 onto beaches, which may in turn lead to human infection. To simulate contamination, freshwater mixed with cattle slurry containing E. coli O157:H7 was added to sand from three recreational beaches. The sand was then maintained in a dry state (nontidal) or subjected to a repeated seawater tidal simulation. The pathogen could still be recovered from all sands by day 5. Although survival of the pathogen did not statistically vary between sands of different origin under nontidal conditions, significant differences in numbers occurred between sands when subject to tidal simulation. In the tidal simulations, a considerable proportion of the E. coli O157:H7 rapidly dissipated from sand into the seawater. In a separate experiment, the activity of bioluminescent (lux-marked) E. coli O157:H7 cells was monitored in various mixtures of contaminated runoff water and seawater over 5 days. Pathogen activity declined with increasing seawater concentration; however, cells remained viable in all treatments over the 5-day period. The addition of nutrients to water rapidly increased pathogen activity in all treatments. Our findings highlight the resilience of E. coli O157:H7 in aquatic and marine environments.
Contour-clamped homogeneous electric field pulsed-field gel electrophoresis (CHEF-PFGE) was used to compare Wisconsin isolates of Escherichia coli O157:H7, including 39 isolates from a 1994 day care center outbreak, 28 isolates from 18 individuals from the surrounding geographic area with sporadic cases occurring during the 3 months before the outbreak, and 3 isolates, collected in 1995, from patients with hemolytic-uremic syndrome (HUS) who were from eastern Wisconsin counties other than those inhabited by the day care center and sporadic-case individuals. The technique of CHEF-PFGE using XbaI identified seven highly related restriction endonuclease digestion profiles (REDPs) (93 to 98% similarity) among the 39 day care center isolates and nine XbaI REDPs (63 to 93% similarity) among the 28 isolates from sporadic-case individuals, including REDP 33, which was exhibited by both day care and sporadic-case isolates. PFGE analyses of sequential E. coli O157:H7 isolates from symptomatic day care center attendees revealed that the REDPs of 25 isolates from eight patients were indistinguishable whereas the REDPs of 2 of 6 isolates from two patients differed slightly (93 to 95% similarity). The REDPs of the three isolates from 1995 HUS patients were 78 to 83% similar, with REDP 26 being exhibited by one HUS-associated isolate and an isolate from one day care attendee who did not develop HUS. The genes for both Shiga toxins I and II (stx1 and stx2, respectively) were detected in all but one isolate (sporadic case), and Shiga toxin production by the day care center isolates was not significantly different from that of the other isolates, including the three HUS-associated isolates. Analyses of E. coli O157:H7 isolates from both the day care center outbreak and sporadic cases by CHEF-PFGE permitted us to define the REDP variability of an outbreak and geographic region and demonstrated that the day care center outbreak and a HUS case in 1995 were caused by E. coli O157:H7 strains endemic to eastern Wisconsin.
A point source outbreak of haemorrhagic colitis due to Escherichia coli O 157.H7 producing verocytotoxin (VT), took place following a christening party in Birmingham in June 1987. Twenty-six people were affected, six were admitted to hospital and one developed haemolytic uraemic syndrome: there were no deaths. VT + E. coli O 157.H7 was isolated from 13 (57%) of 23 faecal specimens from affected people and from 3 (9%) of 33 specimens from asymptomatic people. Free VT was detected in the faeces of one further asymptomatic person. Illness was associated with eating turkey-roll sandwiches (P less than 0.001) suggesting that cold meats might be an important source of infection.