Where's the beef? The role of cross-contamination in 4 chain restaurant-associated outbreaks of Escherichia coli O157:H7 in the Pacific Northwest.

BACKGROUND: From March through August 1993, outbreaks of Escherichia coli O157:H7 occurred at 4 separate Oregon and Washington steak and salad bar restaurants affiliated with a single national chain. OBJECTIVE: To determine the cause of outbreaks of E coli O157:H7 at 4 chain restaurants. METHODS: Independent case-control studies were performed for each outbreak. Available E coli O157:H7 isolates were subtyped by pulse-field gel electrophoresis and by phage typing. RESULTS: Infection was not associated with beef consumption at any of the restaurants. Implicated foods varied by restaurant but all were items served at the salad bar. Among the salad bar items, no single item was implicated in all outbreaks, and no single item seemed to explain most of the cases at any individual restaurant. Molecular subtyping of bacterial isolates indicated that the first 2 outbreaks, which occurred concurrently, were caused by the same strain, the third outbreak was caused by a unique strain, and the fourth was multiclonal. CONCLUSIONS: Independent events of cross-contamination from beef within the restaurant kitchens, where meats and multiple salad bar items were prepared, were the likely cause of these outbreaks. Meat can be a source of E coli O157:H7 infection even if it is later cooked properly, underscoring the need for meticulous food handling at all stages of preparation.

Illnesses and absence due to illness among children attending child care facilities in Seattle-King County, Washington.

OBJECTIVES: Although much of the economic impact of child care-associated illness in the United States is due to parents' time lost from work, there are no data on the incidence of absence due to illness among children in various types of out-of-home child care settings in the United States. The goals of this study were to compare the incidence of illness and absence due to illness among children attending child care homes (CCHs) and child care centers (CCCs). METHODS: From July 1992 through June 1993, child care providers from 91 CCHs and 41 CCCs in Seattle-King County, Washington, provided information on absenteeism and illness for 96 792 child-weeks of observation. RESULTS: The age-adjusted incidence of provider-reported illness episodes among children in CCHs (10.4 episodes per 100 child-weeks) was greater than that among children in CCCs (6.7 episodes per 100 child-weeks). The incidence density ratio of illness among children <1 year of age in comparison to those >/=5 years of age in CCCs (4.5) was greater than that among similar groups in CCHs (2.3). The age-adjusted incidence of absence due to illness among children in CCHs (5.1 days per 100 child-weeks) was less than that among children in CCCs (8.9 days per 100 child-weeks). CONCLUSIONS: Results comparing the incidence of illness between children in various types of child care settings may be influenced by information sources. The incidence of illness among children in CCHs may be greater than that among children in CCCs. The increased incidence of absence due to illness among children in CCCs compared with that among children in CCHs probably reflects differences in exclusion and attendance policies and practices between these two types of settings.

Active and passive surveillance for communicable diseases in child care facilities, Seattle-King County, Washington.

OBJECTIVES: The purpose of this study was to develop and evaluate models for public health surveillance of illnesses among children in out-of-home child care facilities. METHODS: Between July 1992 and March 1994, 200 Seattle-King County child care facilities participated in active or enhanced passive surveillance, or both. Reporting was based on easily recognized signs, symptoms, and sentinel events. Published criteria were used in evaluating surveillance effectiveness, and notifiable disease reporting of participating and nonparticipating facilities was compared. RESULTS: Neither surveillance model was well accepted by child care providers. Enhanced passive and active surveillance had comparable sensitivity. Reporting delays and the large amount of time needed for data entry led to problems with timeliness, especially in terms of written reporting during active surveillance. CONCLUSIONS: Widespread active public health surveillance in child care facilities is not feasible for most local health departments. Improvements in public health surveillance in child care settings will depend on acceptability to providers.

Evaluation of the use of mass chemoprophylaxis during a school outbreak of enzyme type 5 serogroup B meningococcal disease.

BACKGROUND: A vaccine for prevention of serogroup B meningococcal disease is not available in the United States, and indications for the use of mass chemoprophylaxis for control of meningococcal outbreaks are not well-defined. In response to an outbreak of six cases of enzyme type 5 serogroup B meningococcal disease among students at a middle school, we implemented a program of mass rifampin prophylaxis and evaluated the effectiveness of this preventive measure. METHODS: Oropharyngeal cultures were obtained from 351 of the 900 students before prophylaxis; 196 participants were recultured 3 weeks later. Meningococcal isolates were subtyped and tested for rifampin susceptibility, and risk factors for disease or carriage among students were evaluated. RESULTS: No cases occurred after prophylaxis. Before prophylaxis 10% (34 of 351) of students were meningococcal carriers and 3.4% (12 of 351) carried the epidemic strain. After prophylaxis 2.5% (5 of 196) were carriers and 1.0% (2 of 196) carried the epidemic strain. Rifampin was 85% effective in eradicating carriage, and the rate of acquisition of carriage during the 3-week period was low (0.5%). Carriage persisted after prophylaxis in 4 students; 3 of these postprophylaxis isolates were rifampin-resistant. Rifampin resistance thus developed in 12% (3 of 26) of preprophylaxis isolates. Disease/epidemic strain carriage was associated with enrollment in the school band and certain other classes. CONCLUSIONS: These findings suggests that mass chemoprophylaxis may be effective and should be considered for control of school serogroup B meningococcal outbreaks. This approach is less likely to be effective for control of outbreaks affecting larger, less well-defined populations and is associated with the rapid development of antibiotic resistance.

Risk of infection with hepatitis A, B or C, cytomegalovirus, varicella or measles among child care providers.

BACKGROUND: Employment as a child care provider has been suggested as an indication for hepatitis A virus (HAV) immunization; however, whether this occupational group is at increased risk of HAV infection is not well-defined. METHODS: We obtained sera samples for testing for antibodies to hepatitis A, B and C, cytomegalovirus, varicella and measles from a sample of child care providers in King County, WA, and administered a questionnaire to assess employment characteristics and other potential risk factors for infection. We also compared the anti-HAV seroprevalence among providers with that of subjects in the Third National Health and Nutrition Survey, representative of the US general population. RESULTS: Thirteen percent (48 of 360) of providers were anti-HAV-positive (46% (22 of 47) of foreign born vs. 8% (26 of 313) of US-born (P < 0.001)). In multivariate analysis anti-HAV seropositivity was associated with foreign birth, age, income and Hispanic ethnicity but was not associated with characteristics of employment. Seroprevalence among US-born providers tended to be lower than that among Third National Health and Nutrition Survey subjects of similar age, sex, race and income. Sixty-two percent of providers were seropositive to cytomegalovirus, which was associated with nonwhite race, changing diapers > or = 3 days/week while at work and having a child in the household. Antibody prevalence was 1.4% to hepatitis B core antigen, 0.6% to hepatitis C, 94% to measles and 98% to varicella. CONCLUSIONS: The anti-HAV prevalence among US-born providers was low, and seropositivity was not associated with employment characteristics, indicating that occupational exposure to HAV is uncommon under non-outbreak circumstances.

Injuries and their relation to potential hazards in child day care.

OBJECTIVES: To prospectively determine the incidence rate of injuries that required medical attention among children in day care and to identify possible hazards related to these injuries. SETTING: King County, Washington. METHODS: Prospective cohort study of children in a sample of licensed day care facilities. RESULTS: From 1 July 1992 to 30 June 1993, 53 medically attended injuries were reported by 133 day care sites; incidence rate 1.9 per 100,000 hours of day care attendance. The rate of injury in 91 small family day care homes was essentially the same as that in 42 larger day care centers; relative rate 1.0 (95% confidence interval 0.6 to 1.9). Injuries that required sutures accounted for 39% of the cases, while 17% required a cast, splint, or sling. No child was hospitalized. Sixty nine sites were inspected and all had potentially correctable physical hazards, with a median of 15 hazards per site (range 7 to 26). These potential hazards had little relationship to the risk of injury and a case-by-case review identified only two injuries that might have been prevented by a more energy absorbent playground surface. CONCLUSIONS: The incidence of medically attended injuries found in this study is consistent with other studies from the United States. Most injuries were minor and had little relation to physical hazards at day care locations.

Control of day care shigellosis: a trial of convalescent day care in isolation.

Simultaneous outbreaks of S. sonnei infections occurred in September 1983 at two day care centers in Seattle, Washington. At both centers, there were high rates of diarrheal illness in the children (22/80 and 11/23, respectively), in staff members, and in family members of the ill children. The smaller center was temporarily closed, but the larger one remained open. Convalescent children and staff whose diarrhea had resolved and who were receiving appropriate antimicrobials were allowed to return to the larger center before negative cultures were obtained and were separated in an isolation room. No culture-proven cases of shigellosis occurred at either center in the following two months. Plasmid profile determinations suggested the Shigella were not transmitted from the center that remained open to the community. Estimated need for alternate child care requirements at the closed center were 100-fold greater than at the center with the isolation room. Caring for convalescent children in isolation at day care centers while they receive antimicrobial therapy may be a useful strategy for controlling day care shigellosis.

Regulation and the paramedical professions: an interest group study.

This article examines the relationship between government regulation and interest group activity of two paramedical groups in Ontario: chiropractors and physioptherapists. These disciplines occupy positions vis-à-vis the provincial medical insurance plan opposite to those which their relationships with the medical profession would suggest. It will be argued that the employment of sophisticated pressure group tactics can be highly effective as a surrogate for medical recognition. This, in conjunction with the difficulties inherent in the exercise of lay judgment in the development of public policy toward the professions, can lead to controversial policy outputs. It will also become apparent that a close and legitimate association with the medical profession is not necessarily of benefit in the pursuit of professional recognition.