Timothy F. Jones

Antimicrobial-Resistant Nontyphoidal Salmonella Is Associated with Excess Bloodstream Infections and Hospitalizations

BACKGROUND Nontyphoidal Salmonella is a leading cause of foodborne illness. Few studies have explored the health consequences of antimicrobial-resistant Salmonella. METHODS The National Antimicrobial Resistance Monitoring System (NARMS) performs susceptibility testing on nontyphoidal Salmonella isolates. The Foodborne Diseases Active Surveillance Network (FoodNet) ascertains outcomes for patients with culture-confirmed Salmonella infection, in 9 states, each of which participates in NARMS. We analyzed the frequency of bloodstream infection and hospitalization among patients with resistant infections. Isolates defined as resistant to a clinically important agent were resistant to 1 or more of the following agents: ampicillin, ceftriaxone, ciprofloxacin, gentamicin, and/or trimethoprim-sulfamethoxazole. RESULTS During 1996-2001, NARMS received 7370 serotyped, nontyphoidal Salmonella isolates from blood or stool. Bloodstream infection occurred more frequently among patients infected with an isolate resistant to > or =1 clinically important agent (adjusted odds ratio [OR], 1.6; 95% confidence interval [CI], 1.2-2.1), compared with patients with pansusceptible infection. During 1996-2001, FoodNet staff ascertained outcomes for 1415 patients who had isolates tested in NARMS. Hospitalization with bloodstream infection occurred more frequently among patients infected with an isolate resistant to > or =1 clinically important agent (adjusted OR, 3.1; 95% CI, 1.4-6.6), compared with patients with pansusceptible infection. CONCLUSIONS Patients with antimicrobial-resistant nontyphoidal Salmonella infection were more likely to have bloodstream infection and to be hospitalized than were patients with pansusceptible infection. Mitigation of antimicrobial resistance in Salmonella will likely benefit human health.

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.

Antimicrobial resistance among Campylobacter strains, United States, 1997-2001.

We summarize antimicrobial resistance surveillance data in human and chicken isolates of Campylobacter. Isolates were from a sentinel county study from 1989 through 1990 and from nine state health departments participating in National Antimicrobial Resistance Monitoring System for enteric bacteria (NARMS) from 1997 through 2001. None of the 297 C. jejuni or C. coli isolates tested from 1989 through 1990 was ciprofloxacin-resistant. From 1997 through 2001, a total of 1,553 human Campylobacter isolates were characterized: 1,471 (95%) were C. jejuni, 63 (4%) were C. coli, and 19 (1%) were other Campylobacter species. The prevalence of ciprofloxacin-resistant Campylobacter was 13% (28 of 217) in 1997 and 19% (75 of 384) in 2001; erythromycin resistance was 2% (4 of 217) in 1997 and 2% (8 of 384) in 2001. Ciprofloxacin-resistant Campylobacter was isolated from 10% of 180 chicken products purchased from grocery stores in three states in 1999. Ciprofloxacin resistance has emerged among Campylobacter since 1990 and has increased in prevalence since 1997.

Multistate outbreak of Listeria monocytogenes infection linked to delicatessen turkey meat.

BACKGROUND Despite a decreasing incidence of listeriosis in the United States, molecular subtyping has increased the number of recognized outbreaks. In September 2000, the New York City Department of Health identified a cluster of infections caused by Listeria monocytogenes isolates with identical molecular subtypes by pulsed-field gel electrophoresis (PFGE) and ribotyping. METHODS To determine the magnitude of the outbreak and identify risk factors for infection, we notified state health departments and conducted a case-control study. A case was defined as a patient or mother-infant pair infected with Listeria monocytogenes whose isolate yielded the outbreak PFGE pattern. Controls were patients infected with Listeria monocytogenes whose isolate yielded a different PFGE pattern. Patients were asked about food and drink consumed during the 30 days before the onset of illness. RESULTS Between May and December 2000, there were 30 clinical isolates of Listeria monocytogenes with identical PFGE patterns identified in 11 US states. Cases of infection caused by these isolates were associated with 4 deaths and 3 miscarriages. A case-control study implicated sliced processed turkey from a delicatessen (Mantel-Haenszel odds ratio, 8.0; 95% confidence interval, 1.2-43.3). A traceback investigation identified a single processing plant as the likely source of the outbreak, and the company voluntarily recalled 16 million pounds of processed meat. The same plant had been identified in a Listeria contamination event that had occurred more than a decade previously. CONCLUSIONS Prevention of persistent L. monocytogenes contamination in food processing plants presents a critical challenge to food safety professionals.

An Outbreak of Community-Acquired Foodborne Illness Caused by Methicillin-Resistant Staphylococcus aureus

Infections with methicillin-resistant Staphylococcus aureus (MRSA) are increasingly community acquired. We investigated an outbreak in which a food handler, food specimen, and three ill patrons were culture positive for the same toxin-producing strain of MRSA. This is the first report of an outbreak of gastrointestinal illness caused by community-acquired MRSA.

Fungal Infections Associated with Contaminated Methylprednisolone in Tennessee

BACKGROUND We investigated an outbreak of fungal infections of the central nervous system that occurred among patients who received epidural or paraspinal glucocorticoid injections of preservative-free methylprednisolone acetate prepared by a single compounding pharmacy. METHODS Case patients were defined as patients with fungal meningitis, posterior circulation stroke, spinal osteomyelitis, or epidural abscess that developed after epidural or paraspinal glucocorticoid injections. Clinical and procedure data were abstracted. A cohort analysis was performed. RESULTS The median age of the 66 case patients was 69 years (range, 23 to 91). The median time from the last epidural glucocorticoid injection to symptom onset was 18 days (range, 0 to 56). Patients presented with meningitis alone (73%), the cauda equina syndrome or focal infection (15%), or posterior circulation stroke with or without meningitis (12%). Symptoms and signs included headache (in 73% of the patients), new or worsening back pain (in 50%), neurologic symptoms (in 48%), nausea (in 39%), and stiff neck (in 29%). The median cerebrospinal fluid white-cell count on the first lumbar puncture among patients who presented with meningitis, with or without stroke or focal infection, was 648 per cubic millimeter (range, 6 to 10,140), with 78% granulocytes (range, 0 to 97); the protein level was 114 mg per deciliter (range, 29 to 440); and the glucose concentration was 44 mg per deciliter (range, 12 to 121) (2.5 mmol per liter [range, 0.7 to 6.7]). A total of 22 patients had laboratory confirmation of Exserohilum rostratum infection (21 patients) or Aspergillus fumigatus infection (1 patient). The risk of infection increased with exposure to lot 06292012@26, older vials, higher doses, multiple procedures, and translaminar approach to epidural glucocorticoid injection. Voriconazole was used to treat 61 patients (92%); 35 patients (53%) were also treated with liposomal amphotericin B. Eight patients (12%) died, seven of whom had stroke. CONCLUSIONS We describe an outbreak of fungal meningitis after epidural or paraspinal glucocorticoid injection with methylprednisolone from a single compounding pharmacy. Rapid recognition of illness and prompt initiation of therapy are important to prevent complications. (Funded by the Tennessee Department of Health and the Centers for Disease Control and Prevention.).

Hemolytic Uremic Syndrome and Death in Persons with Escherichia coli O157:H7 Infection, Foodborne Diseases Active Surveillance Network Sites, 2000-2006

BACKGROUND Hemolytic uremic syndrome (HUS) is a life-threatening illness usually caused by infection with Shiga toxin-producing Escherichia coli O157 (STEC O157). We evaluated the age-specific rate of HUS and death among persons with STEC O157 infection and the risk factors associated with developing HUS. METHODS STEC O157 infections and HUS cases were reported from 8 sites participating in the Foodborne Diseases Active Surveillance Network during 2000-2006. For each case of STEC O157 infection and HUS, demographic and clinical outcomes were reported. The proportion of STEC O157 infections resulting in HUS was determined. RESULTS A total of 3464 STEC O157 infections were ascertained; 218 persons (6.3%) developed HUS. The highest proportion of HUS cases (15.3%) occurred among children aged <5 years. Death occurred in 0.6% of all patients with STEC O157 infection and in 4.6% of those with HUS. With or without HUS, persons aged 60 years had the highest rate of death due to STEC O157 infection. Twelve (3.1%) of 390 persons aged 60 years died, including 5 (33.3%) of 15 persons with HUS and 7 (1.9%) of 375 without. Among children aged <5 years, death occurred in 4 (3.0%) of those with HUS and 2 (0.3%) of those without. CONCLUSIONS Young children and females had an increased risk of HUS after STEC O157 infection. With or without HUS, elderly persons had the highest proportion of deaths associated with STEC O157 infection. These data support recommendations for aggressive supportive care of young children and the elderly early during illness due to STEC O157.

Invasive Listeriosis in the Foodborne Diseases Active Surveillance Network (FoodNet), 2004–2009: Further Targeted Prevention Needed for Higher-Risk Groups

BACKGROUND Listeriosis can cause severe disease, especially in fetuses, neonates, older adults, and persons with certain immunocompromising and chronic conditions. We summarize US population-based surveillance data for invasive listeriosis from 2004 through 2009. METHODS We analyzed Foodborne Diseases Active Surveillance Network (FoodNet) data for patients with Listeria monocytogenes isolated from normally sterile sites. We describe the epidemiology of listeriosis, estimate overall and specific incidence rates, and compare pregnancy-associated and nonpregnancy-associated listeriosis by age and ethnicity. RESULTS A total of 762 listeriosis cases were identified during the 6-year reporting period, including 126 pregnancy-associated cases (17%), 234 nonpregnancy-associated cases(31%) in patients aged <65 years, and 400 nonpregnancy-associated cases (53%) in patients aged ≥ 65 years. Eighteen percent of all cases were fatal. Meningitis was diagnosed in 44% of neonates. For 2004-2009, the overall annual incidence of listeriosis varied from 0.25 to 0.32 cases per 100,000 population. Among Hispanic women, the crude incidence of pregnancy-associated listeriosis increased from 5.09 to 12.37 cases per 100,000 for the periods of 2004-2006 and 2007-2009, respectively; among non-Hispanic women, pregnancy-associated listeriosis increased from 1.74 to 2.80 cases per 100,000 for the same periods. Incidence rates of nonpregnancy-associated listeriosis in patients aged ≥ 65 years were 4-5 times greater than overall rates annually. CONCLUSIONS Overall listeriosis incidence did not change significantly from 2004 through 2009. Further targeted prevention is needed, including food safety education and messaging (eg, avoiding Mexican-style cheese during pregnancy). Effective prevention among pregnant women, especially Hispanics, and older adults would substantially affect overall rates.

Listeria monocytogenes Infection from Foods Prepared in a Commercial Establishment: A Case-Control Study of Potential Sources of Sporadic Illness in the United States

BACKGROUND Listeria monocytogenes has been estimated to cause >2500 illnesses and 500 deaths annually in the United States. Efforts to reduce foodborne listeriosis have focused on foods frequently implicated in outbreaks. Potential sources for L. monocytogenes infection not associated with outbreaks remain poorly understood. METHODS The Foodborne Diseases Active Surveillance Network conducts surveillance for culture-confirmed listeriosis at clinical laboratories in 9 states. After excluding outbreak-associated cases, we attempted to enroll eligible case patients with L. monocytogenes infection in a case-control study from 2000 through 2003. Control subjects were recruited through health care providers and were matched to case patients by state, age, and immunosuppression status. Data were collected about exposures occurring in the 4 weeks before specimen collection from the case patients. RESULTS Of the 249 case patients with L. monocytogenes infection, only 12 (5%) had cases that were associated with outbreaks; 6 other patients were ineligible for other reasons. Of 231 eligible case patients, 169 (73%) were enrolled in the study. We classified 28 case patients as having pregnancy-associated cases. We enrolled 376 control subjects. In multivariable analysis, L. monocytogenes infection was associated with eating melons at a commercial establishment (odds ratio, 2.6; 95% confidence interval, 1.4-5.0) and eating hummus prepared in a commercial establishment (odds ratio, 5.7; 95% confidence interval, 1.7-19.1). CONCLUSIONS Most cases of L. monocytogenes infection were not associated with outbreaks. Reducing the burden of foodborne listeriosis may require interventions directed at retail environments and at foods, such as melons and hummus, that are not commonly recognized as high risk. Because of the severity of listeriosis, pregnant women and other persons at risk may wish to avoid eating these newly implicated foods.

Systematic Environmental Evaluations To Identify Food Safety Differences between Outbreak and Nonoutbreak Restaurants

Restaurants are important settings for foodborne disease transmission. The Environmental Health Specialists Network (EHS-Net) was established to identify underlying factors contributing to disease outbreaks and to translate those findings into improved prevention efforts. From June 2002 through June 2003, EHS-Net conducted systematic environmental evaluations in 22 restaurants in which outbreaks had occurred and 347 restaurants in which outbreaks had not occurred. Norovirus was the most common foodborne disease agent identified, accounting for 42% of all confirmed foodborne outbreaks during the study period. Handling of food by an infected person or carrier (65%) and bare-hand contact with food (35%) were the most commonly identified contributing factors. Outbreak and nonoutbreak restaurants were similar with respect to many characteristics. The major difference was in the presence of a certified kitchen manager (CKM); 32% of outbreak restaurants had a CKM, but 71% of nonoutbreak restaurants had a CKM (odds ratio of 0.2; 95% confidence interval of 0.1 to 0.5). CKMs were associated with the absence of bare-hand contact with foods as a contributing factor, fewer norovirus outbreaks, and the absence of outbreaks associated with Clostridium perfringens. However, neither the presence of a CKM nor the presence of policies regarding employee health significantly affected the identification of an infected person or carrier as a contributing factor. These findings suggest a lack of effective monitoring of employee illness or a lack of commitment to enforcing policies regarding ill food workers. Food safety certification of kitchen managers appears to be an important outbreak prevention measure, and managing food worker illnesses should be emphasized during food safety training programs.