Modelling counterfactual incidence during the transition towards culture-independent diagnostic testing

BACKGROUND

Culture-independent diagnostic testing (CIDT) provides rapid results to clinicians and is quickly displacing traditional detection methods. Increased CIDT use and sensitivity likely result in higher case detection but might also obscure infection trends. Severe illness outcomes, such as hospitalization and death, are likely less affected by changes in testing practices and can be used as indicators of the expected case incidence trend had testing methods not changed.

METHODS

Using US Foodborne Diseases Active Surveillance Network data during 1996-2019 and mixed effects quasi-Poisson regression, we estimated the expected yearly incidence for nine enteric pathogens.

RESULTS

Removing the effect of CIDT use, CIDT panel testing and culture-confirmation of CIDT testing, the modelled incidence in all but three pathogens (Salmonella, Shigella, STEC O157) was significantly lower than the observed and the upward trend in Campylobacter was reversed from an observed 2.8% yearly increase to a modelled -2.8% yearly decrease (95% credible interval: -4.0, -1.4).

CONCLUSIONS

Severe outcomes may be useful indicators in evaluating trends in surveillance systems that have undergone a marked change.

Absence of SARS-CoV-2 infections among patients with end-stage renal disease following facility-wide testing in four outpatient hemodialysis facilities

Facility-wide testing performed at 4 outpatient hemodialysis facilities in the absence of an outbreak or escalating community incidence did not identify new SARS-CoV-2 infections and illustrated key logistical considerations essential to successful implementation of SARS-CoV-2 screening. Facilities could consider prioritizing facility-wide SARS-CoV-2 testing during suspicion of an outbreak in the facility or escalating community spread without robust infection control strategies in place. Being prepared to address operational considerations will enhance implementation of facility-wide testing in the outpatient dialysis setting.

Characteristics and Risk Factors of Hospitalized and Nonhospitalized COVID-19 Patients, Atlanta, Georgia, USA, March-April 2020

We compared the characteristics of hospitalized and nonhospitalized patients who had coronavirus disease in Atlanta, Georgia, USA. We found that risk for hospitalization increased with a patient’s age and number of concurrent conditions. We also found a potential association between hospitalization and high hemoglobin A1c levels in persons with diabetes.

Shigella Bacteremia, Georgia, USA, 2002-20121

Shigella commonly causes gastroenteritis but rarely spreads to the blood. During 2002–2012, we identified 11,262 Shigella infections through population-based active surveillance in Georgia; 72 (0.64%) were isolated from blood. Bacteremia was associated with age >18 years, black race, and S. flexneri. More than half of patients with bacteremia were HIV-infected.

Predictors at admission of mechanical ventilation and death in an observational cohort of adults hospitalized with COVID-19

Background

Coronavirus disease (COVID-19) can cause severe illness and death. Predictors of poor outcome collected on hospital admission may inform clinical and public health decisions.

Methods

We conducted a retrospective observational cohort investigation of 297 adults admitted to eight academic and community hospitals in Georgia, United States, during March 2020. Using standardized medical record abstraction, we collected data on predictors including admission demographics, underlying medical conditions, outpatient antihypertensive medications, recorded symptoms, vital signs, radiographic findings, and laboratory values. We used random forest models to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CI) for predictors of invasive mechanical ventilation (IMV) and death.

Results

Compared with age <45 years, ages 65–74 years and ≥75 years were predictors of IMV (aOR 3.12, CI 1.47–6.60; aOR 2.79, CI 1.23–6.33) and the strongest predictors for death (aOR 12.92, CI 3.26–51.25; aOR 18.06, CI 4.43–73.63). Comorbidities associated with death (aORs from 2.4 to 3.8, p <0.05) included end-stage renal disease, coronary artery disease, and neurologic disorders, but not pulmonary disease, immunocompromise, or hypertension. Pre-hospital use vs. non-use of angiotensin receptor blockers (aOR 2.02, CI 1.03–3.96) and dihydropyridine calcium channel blockers (aOR 1.91, CI 1.03–3.55) were associated with death.

Conclusions

After adjustment for patient and clinical characteristics, older age was the strongest predictor of death, exceeding comorbidities, abnormal vital signs, and laboratory test abnormalities. That coronary artery disease, but not chronic lung disease, was associated with death among hospitalized patients warrants further investigation, as do associations between certain antihypertensive medications and death.

SARS-CoV-2-Associated Deaths Among Persons Aged <21 Years - United States, February 12-July 31, 2020

Since February 12, 2020, approximately 6.5 million cases of SARS-CoV-2 infection, the cause of coronavirus disease 2019 (COVID-19), and 190,000 SARS-CoV-2-associated deaths have been reported in the United States (1,2). Symptoms associated with SARS-CoV-2 infection are milder in children compared with adults (3). Persons aged <21 years constitute 26% of the U.S. population (4), and this report describes characteristics of U.S. persons in that population who died in association with SARS-CoV-2 infection, as reported by public health jurisdictions. Among 121 SARS-CoV-2-associated deaths reported to CDC among persons aged <21 years in the United States during February 12-July 31, 2020, 63% occurred in males, 10% of decedents were aged <1 year, 20% were aged 1-9 years, 70% were aged 10-20 years, 45% were Hispanic persons, 29% were non-Hispanic Black (Black) persons, and 4% were non-Hispanic American Indian or Alaska Native (AI/AN) persons. Among these 121 decedents, 91 (75%) had an underlying medical condition,* 79 (65%) died after admission to a hospital, and 39 (32%) died at home or in the emergency department (ED).^† These data show that nearly three quarters of SARS-CoV-2-associated deaths among infants, children, adolescents, and young adults have occurred in persons aged 10-20 years, with a disproportionate percentage among young adults aged 18-20 years and among Hispanics, Blacks, AI/ANs, and persons with underlying medical conditions. Careful monitoring of SARS-CoV-2 infections, deaths, and other severe outcomes among persons aged <21 years remains particularly important as schools reopen in the United States. Ongoing evaluation of effectiveness of prevention and control strategies will also be important to inform public health guidance for schools and parents and other caregivers.

Characteristics Associated with Hospitalization Among Patients with COVID-19 - Metropolitan Atlanta, Georgia, March-April 2020

The first reported U.S. case of coronavirus disease 2019 (COVID-19) was detected in January 2020 (1). As of June 15, 2020, approximately 2 million cases and 115,000 COVID-19-associated deaths have been reported in the United States.* Reports of U.S. patients hospitalized with SARS-CoV-2 infection (the virus that causes COVID-19) describe high proportions of older, male, and black persons (2-4). Similarly, when comparing hospitalized patients with catchment area populations or nonhospitalized COVID-19 patients, high proportions have underlying conditions, including diabetes mellitus, hypertension, obesity, cardiovascular disease, chronic kidney disease, or chronic respiratory disease (3,4). For this report, data were abstracted from the medical records of 220 hospitalized and 311 nonhospitalized patients aged ≥18 years with laboratory-confirmed COVID-19 from six acute care hospitals and associated outpatient clinics in metropolitan Atlanta, Georgia. Multivariable analyses were performed to identify patient characteristics associated with hospitalization. The following characteristics were independently associated with hospitalization: age ≥65 years (adjusted odds ratio [aOR] = 3.4), black race (aOR = 3.2), having diabetes mellitus (aOR = 3.1), lack of insurance (aOR = 2.8), male sex (aOR = 2.4), smoking (aOR = 2.3), and obesity (aOR = 1.9). Infection with SARS-CoV-2 can lead to severe outcomes, including death, and measures to protect persons from infection, such as staying at home, social distancing (5), and awareness and management of underlying conditions should be emphasized for those at highest risk for hospitalization with COVID-19. Measures that prevent the spread of infection to others, such as wearing cloth face coverings (6), should be used whenever possible to protect groups at high risk. Potential barriers to the ability to adhere to these measures need to be addressed.

Pediatric Dental Clinic-Associated Outbreak of Mycobacterium abscessus Infection

BACKGROUND

Mycobacterium abscessus is an uncommon cause of invasive odontogenic infection.

METHODS

M abscessus-associated odontogenic infections occurred in a group of children after they each underwent a pulpotomy. A probable case-child was defined as a child with facial or neck swelling and biopsy-confirmed granulomatous inflammation after a pulpotomy between October 1, 2013, and September 30, 2015. M abscessus was isolated by culture in confirmed case-children. Clinical presentation, management, and outcomes were determined by medical record abstraction.

RESULTS

Among 24 children, 14 (58%) were confirmed case-children. Their median age was 7.3 years (interquartile range, 5.8-8.2 years), and the median time from pulpotomy to symptom onset was 74 days (range, 14-262 days). Clinical diagnoses included cervical lymphadenitis (24 [100%] of 24), mandibular or maxillary osteomyelitis (11 [48%] of 23), and pulmonary nodules (7 [37%] of 19). Each child had ≥1 hospitalization and a median of 2 surgeries (range, 1-6). Of the 24 children, 12 (50%) had surgery alone and 11 (46%) received intravenous (IV) antibiotics. Nineteen of the 24 (79%) children experienced complications, including vascular access malfunction (7 [64%] of 11), high-frequency hearing loss (5 [56%] of 9), permanent tooth loss (11 [48%] of 23), facial nerve palsy (7 [29%] of 24), urticarial rash (3 [25%] of 12), elevated liver enzyme levels (1 [20%] of 5), acute kidney injury (2 [18%] of 11), incision dehiscence/fibrosis (3 [13%] of 24), and neutropenia (1 [9%] of 11).

CONCLUSIONS

M abscessus infection was associated with significant medical morbidity and treatment complications. Unique manifestations included extranodal mandibular or maxillary osteomyelitis and pulmonary nodules. Challenges in the identification of case-children resulted from an extended incubation period and various clinical manifestations. Clinicians should consider the association between M abscessus infection and pulpotomy in children who present with subacute cervical lymphadenitis. The use of treated/sterile water during pulpotomy might prevent further outbreaks.

Association between community socioeconomic factors, animal feeding operations, and campylobacteriosis incidence rates: Foodborne Diseases Active Surveillance Network (FoodNet), 2004-2010

Background

Campylobacter is a leading cause of foodborne illness in the United States. Campylobacter infections have been associated with individual risk factors, such as the consumption of poultry and raw milk. Recently, a Maryland-based study identified community socioeconomic and environmental factors that are also associated with campylobacteriosis rates. However, no previous studies have evaluated the association between community risk factors and campylobacteriosis rates across multiple U.S. states.

Methods

We obtained Campylobacter case data (2004–2010; n = 40,768) from the Foodborne Diseases Active Surveillance Network (FoodNet) and socioeconomic and environmental data from the 2010 Census of Population and Housing, the 2011 American Community Survey, and the 2007 U.S. Census of Agriculture. We linked data by zip code and derived incidence rate ratios using negative binomial regression models.

Results

Community socioeconomic and environmental factors were associated with both lower and higher campylobacteriosis rates. Zip codes with higher percentages of African Americans had lower rates of campylobacteriosis (incidence rate ratio [IRR]) = 0.972; 95 % confidence interval (CI) = 0.970,0.974). In Georgia, Maryland, and Tennessee, three leading broiler chicken producing states, zip codes with broiler operations had incidence rates that were 22 % (IRR = 1.22; 95 % CI = 1.03,1.43), 16 % (IRR = 1.16; 95 % CI = 0.99,1.37), and 35 % (IRR = 1.35; 95 % CI = 1.18,1.53) higher, respectively, than those of zip codes without broiler operations. In Minnesota and New York FoodNet counties, two top dairy producing areas, zip codes with dairy operations had significantly higher campylobacteriosis incidence rates (IRR = 1.37; 95 % CI = 1.22, 1.55; IRR = 1.19; 95 % CI = 1.04,1.36).

Conclusions

Community socioeconomic and environmental factors are important to consider when evaluating the relationship between possible risk factors and Campylobacter infection.

Training in Infectious Disease Epidemiology through the Emerging Infections Program Sites

EIP sites contribute substantially to training current and future public health professionals.

One objective of the Emerging Infections Program (EIP) of the US Centers for Disease Control and Prevention is to provide training opportunities in infectious disease epidemiology. To determine the extent of training performed since the program's inception in 1995, we reviewed training efforts at the 10 EIP sites. By 2015, all sites hosted trainees (most were graduate public health students and physicians) who worked on a variety of infectious disease surveillance and epidemiologic projects. Trainee projects at all sites were used for graduate student theses or practicums. Numerous projects resulted in conference presentations and publications in peer-reviewed journals. Local public health and health care partners have also benefitted from EIP presentations and training. Consideration should be given to standardizing and documenting EIP training and to sharing useful training initiatives with other state and local health departments and academic institutions.

Postdiarrheal hemolytic uremic syndrome in United States children: clinical spectrum and predictors of in-hospital death

OBJECTIVE

To assess the clinical spectrum of postdiarrheal hemolytic uremic syndrome (D(+)HUS) hospitalizations and sought predictors of in-hospital death to help identify children at risk of poor outcomes.

STUDY DESIGN

We assessed clinical variables collected through population-based surveillance of D(+)HUS in children <18 years old hospitalized in 10 states during 1997-2012 as predictors of in-hospital death by using tree modeling.

RESULTS

We identified 770 cases. Of children with information available, 56.5% (430 of 761) required dialysis, 92.6% (698 of 754) required a transfusion, and 2.9% (22 of 770) died; few had a persistent dialysis requirement (52 [7.3%] of 716) at discharge. The tree model partitioned children into 5 groups on the basis of 3 predictors (highest leukocyte count and lowest hematocrit value during the 7 days before to 3 days after the diagnosis of hemolytic uremic syndrome, and presence of respiratory tract infection [RTI] within 3 weeks before diagnosis). Patients with greater leukocyte or hematocrit values or a recent RTI had a greater probability of in-hospital death. The largest group identified (n = 533) had none of these factors and had the lowest odds of death. Many children with RTI had recent antibiotic treatment for nondiarrheal indications.

CONCLUSION

Most children with D(+)HUS have good hospitalization outcomes. Our findings support previous reports of increased leukocyte count and hematocrit as predictors of death. Recent RTI could be an additional predictor, or a marker of other factors such as antibiotic exposure, that may warrant further study.

Managerial practices regarding workers working while ill

Surveillance data indicate that handling of food by an ill worker is a cause of almost half of all restaurant-related outbreaks. The U.S. Food and Drug Administration (FDA) Food Code contains recommendations for food service establishments, including restaurants, aimed at reducing the frequency with which food workers work while ill. However, few data exist on the extent to which restaurants have implemented FDA recommendations. The Centers for Disease Control and Prevention's Environmental Health Specialists Network (EHS-Net) conducted a study on the topic of ill food workers in restaurants. We interviewed restaurant managers (n = 426) in nine EHS-Net sites. We found that many restaurant policies concerning ill food workers do not follow FDA recommendations. For example, one-third of the restaurants' policies did not specifically address the circumstances under which ill food workers should be excluded from work (i.e., not be allowed to work). We also found that, in many restaurants, managers are not actively involved in decisions about whether ill food workers should work. Additionally, almost 70% of managers said they had worked while ill; 10% said they had worked while having nausea or "stomach flu," possible symptoms of foodborne illness. When asked why they had worked when ill, a third of the managers said they felt obligated to work or their strong work ethic compelled them to work. Other reasons cited were that the restaurant was understaffed or no one was available to replace them (26%), they felt that their symptoms were mild or not contagious (19%), they had special managerial responsibilities that no one else could fulfill (11%), there was non-food handling work they could do (7%), and they would not get paid if they did not work or the restaurant had no sick leave policy (5%). Data from this study can inform future research and help policy makers target interventions designed to reduce the frequency with which food workers work while ill.

Detection and characterization of Mycoplasma pneumoniae during an outbreak of respiratory illness at a university

An outbreak at a university in Georgia was identified after 83 cases of probable pneumonia were reported among students. Respiratory specimens were obtained from 21 students for the outbreak investigation. The TaqMan array card (TAC), a quantitative PCR (qPCR)-based multipathogen detection technology, was used to initially identify Mycoplasma pneumoniae as the causative agent in this outbreak. TAC demonstrated 100% diagnostic specificity and sensitivity compared to those of the multiplex qPCR assay for this agent. All M. pneumoniae specimens (n=12) and isolates (n=10) were found through genetic analysis to be susceptible to macrolide antibiotics. The strain diversity of M. pneumoniae associated with this outbreak setting was identified using a variety of molecular typing procedures, resulting in two P1 genotypes (types 1 [60%] and 2 [40%]) and seven different multilocus variable-number tandem-repeat analysis (MLVA) profiles. Continued molecular typing of this organism, particularly during outbreaks, may enhance the current understanding of the epidemiology of M. pneumoniae and may ultimately lead to a more effective public health response.

Multiple-aetiology enteric infections involving non-O157 Shiga toxin-producing Escherichia coli--FoodNet, 2001-2010

We describe multiple-aetiology infections involving non-O157 Shiga toxin-producing Escherichia coli (STEC) identified through laboratory-based surveillance in nine FoodNet sites from 2001 to 2010. A multiple-aetiology infection (MEI) was defined as isolation of non-O157 STEC and laboratory evidence of any of the other nine pathogens under surveillance or isolation of >1 non-O157 STEC serogroup from the same person within a 7-day period. We compared exposures of patients with MEI during 2001-2010 with those of patients with single-aetiology non-O157 STEC infections (SEI) during 2008-2009 and with those of the FoodNet population from a survey conducted during 2006-2007. In total, 1870 non-O157 STEC infections were reported; 68 (3.6%) were MEI; 60 included pathogens other than non-O157 STEC; and eight involved >1 serogroup of non-O157 STEC. Of the 68 MEI, 21 (31%) were part of six outbreaks. STEC O111 was isolated in 44% of all MEI. Of patients with MEI, 50% had contact with farm animals compared with 29% (P < 0.01) of persons with SEI; this difference was driven by infections involving STEC O111. More patients with non-outbreak-associated MEI reported drinking well water (62%) than respondents in a population survey (19%) (P < 0.01). Drinking well water and having contact with animals may be important exposures for MEI, especially those involving STEC O111.

Food worker experiences with and beliefs about working while ill

Transmission of foodborne pathogens from ill food workers to diners in restaurants is an important cause of foodborne illness outbreaks. The U.S. Food and Drug Administration recommends that food workers with vomiting or diarrhea (symptoms of foodborne illness) be excluded from work. To understand the experiences and characteristics of workers who work while ill, workplace interviews were conducted with 491 food workers from 391 randomly selected restaurants in nine states that participated in the Environmental Health Specialists Network of the Centers for Disease Control and Prevention. Almost 60% of workers recalled working while ill at some time. Twenty percent of workers said that they had worked while ill with vomiting or diarrhea for at least one shift in the previous year. Factors significantly related to workers having said that they had worked while ill with vomiting or diarrhea were worker sex, job responsibilities, years of work experience, concerns about leaving coworkers short staffed, and concerns about job loss. These findings suggest that the decision to work while ill with vomiting or diarrhea is complex and multifactorial.

Estimates of enteric illness attributable to contact with animals and their environments in the United States

BACKGROUND

Contact with animals and their environment is an important, and often preventable, route of transmission for enteric pathogens. This study estimated the annual burden of illness attributable to animal contact for 7 groups of pathogens: Campylobacter species, Cryptosporidium species, Shiga toxin-producing Escherichia coli (STEC) O157, STEC non-O157, Listeria monocytogenes, nontyphoidal Salmonella species, and Yersinia enterocolitica.

METHODS

By using data from the US Foodborne Diseases Active Surveillance Network and other sources, we estimated the proportion of illnesses attributable to animal contact for each pathogen and applied those proportions to the estimated annual number of illnesses, hospitalizations, and deaths among US residents. We established credible intervals (CrIs) for each estimate.

RESULTS

We estimated that 14% of all illnesses caused by these 7 groups of pathogens were attributable to animal contact. This estimate translates to 445 213 (90% CrI, 234 197-774 839) illnesses annually for the 7 groups combined. Campylobacter species caused an estimated 187 481 illnesses annually (90% CrI, 66 259-372 359), followed by nontyphoidal Salmonella species (127 155; 90% CrI, 66 502-219 886) and Cryptosporidium species (113 344; 90% CrI, 22 570-299 243). Of an estimated 4933 hospitalizations (90% CrI, 2704-7914), the majority were attributable to nontyphoidal Salmonella (48%), Campylobacter (38%), and Cryptosporidium (8%) species. Nontyphoidal Salmonella (62%), Campylobacter (22%), and Cryptosporidium (9%) were also responsible for the majority of the estimated 76 deaths (90% CrI, 5-211).

CONCLUSIONS

Animal contact is an important transmission route for multiple major enteric pathogens. Continued efforts are needed to prevent pathogen transmission from animals to humans, including increasing awareness and encouraging hand hygiene.

Salmonella enterica serotype Enteritidis: increasing incidence of domestically acquired infections

BACKGROUND

Salmonella enterica causes an estimated 1 million cases of domestically acquired foodborne illness in humans annually in the United States; Enteritidis (SE) is the most common serotype. Public health authorities, regulatory agencies, food producers, and food processors need accurate information about rates and changes in SE infection to implement and evaluate evidence-based control policies and practices.

METHODS

We analyzed the incidence of human SE infection during 1996-2009 in the Foodborne Diseases Active Surveillance Network (FoodNet), an active, population-based surveillance system for laboratory-confirmed infections. We compared FoodNet incidence with passively collected data from complementary surveillance systems and with rates of SE isolation from processed chickens and egg products; shell eggs are not routinely tested. We also compared molecular subtyping patterns of SE isolated from humans and chickens.

RESULTS

Since the period 1996-1999, the incidence of human SE infection in FoodNet has increased by 44%. This change is mirrored in passive national surveillance data. The greatest relative increases were in young children, older adults, and FoodNet sites in the southern United States. The proportion of patients with SE infection who reported recent international travel has decreased in recent years, whereas the proportion of chickens from which SE was isolated has increased. Similar molecular subtypes of SE are commonly isolated from humans and chickens.

CONCLUSIONS

Most SE infections in the United States are acquired from domestic sources, and the problem is growing. Chicken and eggs are likely major sources of SE. Continued close attention to surveillance data is needed to monitor the impact of recent regulatory control measures.

Validating deaths reported in the Foodborne Diseases Active Surveillance Network (FoodNet): are all deaths being captured?

Accurate information about deaths is important when determining the human health and economic burden of foodborne diseases. We reviewed death certificate data to assess the accuracy of deaths reported to the Foodborne Diseases Active Surveillance Network (FoodNet). Data were highly accurate, and few deaths were missed through active surveillance.

Multistate outbreak of Listeria monocytogenes associated with Mexican-style cheese made from pasteurized milk among pregnant, Hispanic women

Listeriosis is a severe infection caused by Listeria monocytogenes. Since 2004, the Centers for Disease Control and Prevention has requested that listeriosis patients be interviewed using a standardized Listeria Initiative (LI) questionnaire. In January 2009, states and the Centers for Disease Control and Prevention began investigating a multistate outbreak of listeriosis among pregnant, Hispanic women. We defined a case as an illness occurring between October 2008 and March 2009 with an L. monocytogenes isolate indistinguishable from the outbreak strain by pulsed-field gel electrophoresis. We conducted a multistate case-control study using controls that were selected from L. monocytogenes illnesses in non-outbreak-related pregnant, Hispanic women that were reported to the LI during 2004 to 2008. Eight cases in five states were identified. Seven of these were pregnant, Hispanic females aged 21 to 43 years, and one was a 3-year-old Hispanic girl, who was excluded from the study. Seven (100%) cases but only 26 (60%) of 43 controls had consumed Mexican-style cheese in the month before illness (odds ratio, 5.89; 95% confidence interval, 1.07 to ∞; P = 0.04). Cultures of asadero cheese made from pasteurized milk collected at a manufacturing facility during routine sampling by the Michigan Department of Agriculture on 23 February 2009 yielded the outbreak strain, leading to a recall of cheeses produced in the plant. Recalled product was traced to stores where at least three of the women had purchased cheese. This investigation highlights the usefulness of routine product sampling for identifying contaminated foods, of pulsed-field gel electrophoresis analysis to detect multistate outbreaks, and of the LI for providing timely exposure information for case-control analyses. Recalls of contaminated cheeses likely prevented additional illnesses.

Factors associated with food workers working while experiencing vomiting or diarrhea

This study sought to determine the frequency with which food workers said they had worked while experiencing vomiting or diarrhea, and to identify restaurant and worker characteristics associated with this behavior. We conducted interviews with food workers (n=491) and their managers (n=387) in the nine states that participate in the Centers for Disease Control and Prevention's Environmental Health Specialists Network. Restaurant and worker characteristics associated with repeatedly working while experiencing vomiting or diarrhea were analyzed via multivariable regression. Fifty-eight (11.9%) workers said they had worked while suffering vomiting or diarrhea on two or more shifts in the previous year. Factors associated with workers having worked while experiencing vomiting or diarrhea were (i) high volume of meals served, (ii) lack of policies requiring workers to report illness to managers, (iii) lack of on-call workers, (iv) lack of manager experience, and (v) workers of the male gender. Our findings suggest that policies that encourage workers to tell managers when they are ill and that help mitigate pressures to work while ill could reduce the number of food workers who work while experiencing vomiting or diarrhea.

Laboratory practices for the identification of Shiga toxin-producing Escherichia coli in the United States, FoodNet sites, 2007

Clinical laboratory practices affect patient care and disease surveillance. It is recommended that laboratories routinely use both culture for Escherichia coli O157 and a method that detects Shiga toxins (Stx) to identify all Stx-producing E. coli (STEC) and that labs send broths or isolates to a public health laboratory. In 2007, we surveyed laboratories serving Foodborne Diseases Active Surveillance Network sites that performed on-site enteric disease diagnostic testing to determine their culture and nonculture-based testing practices for STEC identification. Our goals were to measure changes over time in laboratory practices and to compare reported practices with published recommendations. Overall, 89% of laboratories used only culture-based methods, 7% used only Stx enzyme immunoassay (EIA), and 4% used both Stx EIA and culture-based methods. Only 2% of laboratories reported simultaneous culture for O157 STEC and use of Stx EIA. The proportion that ever used Stx EIA increased from 6% in 2003 to 11% in 2007. The proportion that routinely tested all specimens with at least one method was 66% in 2003 versus 71% in 2007. Reference laboratories were less likely than others to test all specimens routinely by one or more of these methods (48% vs. 73%, p=0.03). As of 2007, most laboratories complied with recommendations for O157 STEC testing by culture but not with recommendations for detection of non-O157 STEC. The proportion of laboratories that culture stools for O157 STEC has changed little since 2003, whereas testing for Stx has increased.

Recommendations for diagnosis of shiga toxin--producing Escherichia coli infections by clinical laboratories

Shiga toxin--producing Escherichia coli (STEC) are a leading cause of bacterial enteric infections in the United States. Prompt, accurate diagnosis of STEC infection is important because appropriate treatment early in the course of infection might decrease the risk for serious complications such as renal damage and improve overall patient outcome. In addition, prompt laboratory identification of STEC strains is essential for detecting new and emerging serotypes, for effective and timely outbreak responses and control measures, and for monitoring trends in disease epidemiology. Guidelines for laboratory identification of STEC infections by clinical laboratories were published in 2006. This report provides comprehensive and detailed recommendations for STEC testing by clinical laboratories, including the recommendation that all stools submitted for routine testing from patients with acute community-acquired diarrhea (regardless of patient age, season of the year, or presence or absence of blood in the stool) be simultaneously cultured for E. coli O157:H7 (O157 STEC) and tested with an assay that detects Shiga toxins to detect non-O157 STEC. The report also includes detailed procedures for specimen selection, handling, and transport; a review of culture and nonculture tests for STEC detection; and clinical considerations and recommendations for management of patients with STEC infection. Improving the diagnostic accuracy of STEC infection by clinical laboratories should ensure prompt diagnosis and treatment of these infections in patients and increase detection of STEC outbreaks in the community.

Continued decline in the incidence of Campylobacter infections, FoodNet 1996-2006

Campylobacter is a leading cause of foodborne illness worldwide. In the United States, changes in the incidence of culture-confirmed Campylobacter infections have been monitored by the Foodborne Diseases Active Surveillance Network (FoodNet) since 1996. In 2006, the incidence of culture-confirmed Campylobacter infection in the FoodNet sites was 12.7 per 100,000 persons. This represents a 30% decline (95% confidence = 35% to 24% decrease) compared to the 1996-1998 illness baseline; however, most of the decline occurred between 1996 and 1999 and the incidence still remains above the national health objective. Important declines were observed in four FoodNet sites (California, Connecticut, Georgia, and Maryland), all age groups, and both sexes. To promote continued progress towards achieving the national health objective, the epidemiology of Campylobacter infections in the United States, including geographic variation and higher incidence among the very young, warrants further study.

Salmonellosis outcomes differ substantially by serotype

BACKGROUND

Most human infections are caused by closely related serotypes within 1 species of Salmonella. Few data are available on differences in severity of disease among common serotypes.

METHODS

We examined data from all cases of Salmonella infection in FoodNet states during 1996-2006. Data included serotype, specimen source, hospitalization, and outcome.

RESULTS

Among 46,639 cases, 687 serotypes were identified. Overall, 41,624 isolates (89%) were from stool specimens, 2524 (5%) were from blood, and 1669 (4%) were from urine; 10,393 (22%) cases required hospitalization, and death occurred in 219 (0.5%). The case fatality rate for S. Newport (0.3%) was significantly lower than for Typhimurium (0.6%); Dublin (3.0%) was higher. With respect to invasive disease, 13 serotypes had a significantly higher proportion than Typhimurium (6%), including Enteritidis (7%), Heidelberg (13%), Choleraesuis (57%), and Dublin (64%); 13 serotypes were significantly less likely to be invasive. Twelve serotypes, including Enteritidis (21%) and Javiana (21%), were less likely to cause hospitalization than Typhimurium (24%); Choleraesuis (60%) was significantly more so.

CONCLUSIONS

Salmonella serotypes are closely related genetically yet differ significantly in their pathogenic potentials. Understanding the mechanisms responsible for this may be key to a more general understanding of the invasiveness of intestinal bacterial infections.

Co-infection with two different strains of Bordetella pertussis in an infant

We report co-infection with two phenotypically and genotypically distinct strains of Bordetella pertussis in an infant male hospitalized with a 2-week history of cough, paroxysms and vomiting. Colonies from the two B. pertussis phenotypes were isolated and evaluated by PFGE profile analysis, gene sequence typing and PCR-RFLP of a portion of the 23S rRNA gene. These results demonstrated simultaneous infection with two different strains of B. pertussis.