Lisa A. King

Outbreak of Shiga Toxin–Producing Escherichia coli O104:H4 Associated With Organic Fenugreek Sprouts, France, June 2011

BACKGROUND On 22 June 2011, 8 patients with hemolytic uremic syndrome (HUS) or bloody diarrhea were reported in France. All 8 were attendees of a community center event on 8 June near Bordeaux. Three Escherichia coli cases were confirmed by isolation of Shiga toxin-producing E. coli O104:H4 stx2 aggR producing a cefotaximase (CTX-M) β-lactamase (STEC O104:H4); the same rare serotype caused the outbreak in Germany in May-July 2011. An investigation was initiated to describe the outbreak, identify the vehicle for infection, and guide control measures. METHODS We conducted a retrospective cohort study among all adults attending the event, including food handlers. A standardized questionnaire was administered to participants. A case was an attendee who developed HUS or diarrhea between 8 and 24 June. Cases were confirmed by isolation of STEC O104:H4 or O104 serology. Relative risks (RRs) and 95% confidence intervals (CIs) by exposure were calculated using a Poisson regression model. RESULTS Twenty-four cases were identified (14% attack rate). Of these, 18 (75%) were women, 22 (92%) were adults, 7 (29%) developed HUS, 5 (21%) developed bloody diarrhea, and 12 (50%) developed diarrhea. Ten (42%) cases were confirmed. Fenugreek was the only sprout type with an independent association to illness (RR, 5.1; 95% CI, 2.3-11.1) in multivariable analysis. CONCLUSIONS This investigation identified a point-source STEC O104:H4 outbreak associated with consumption of fenugreek sprouts. Comparison of results from French and German STEC O104:H4 outbreak investigations enabled identification of a common food vehicle, fenugreek sprouts, and resulted in implementation of Europe-wide control measures in July 2011.

What is the incubation period for listeriosis

BackgroundListeriosis is a foodborne infection with a low incidence but a high case fatality rate. Unlike common foodborne diseases, the incubation period can be long. The first incubation periods were documented during a large listeriosis outbreak published in 1987 by Linnan and al. in the New England Journal of Medicine (range: 3 days to 70 days). Data on the incubation period of listeriosis are scarce. Our study aim was to estimate precisely the incubation period of listeriosis using available data since 1987.MethodsWe estimated the incubation period of listeriosis using available published data and data from outbreak investigations carried out by the French National Institute for Public Health Surveillance. We selected cases with an incubation period calculated when a patient had a single exposure to a confirmed food source contaminated by Listeria monocytogenes.ResultsWe identified 37 cases of invasive listeriosis (10 cases with central nervous system involvement (CNS cases), 15 bacteraemia cases and 12 pregnancy-associated cases) and 9 outbreaks with gastroenteritis. The overall median incubation period of invasive listeriosis was 8 days (range: 1–67 days) and differed significantly by clinical form of the disease (p<0.0001). A longer incubation period was observed for pregnancy-associated cases (median: 27.5 days; range: 17–67 days) than for CNS cases (median: 9 days; range: 1–14 days) and for bacteraemia cases (median: 2 days; range: 1–12 days). For gastroenteritis cases, the median incubation period was 24 hours with variation from 6 to 240 hours.ConclusionsThis information has implications for the investigation of food borne listeriosis outbreaks as the incubation period is used to determine the time period for which a food history is collected. We believe that, for listeriosis outbreaks, adapting the exposure window for documenting patients’ food histories in accordance with the clinical form of infection will facilitate the identification of food products as the source of contamination. We therefore propose to take an exposure window of 14 days before the diagnosis for CNS and bacteraemia cases, and of 6 weeks before the diagnosis, for pregnancy-associated cases.

High Proportion of Asymptomatic Infections in an Outbreak of Hepatitis E Associated With a Spit-Roasted Piglet, France, 2013

BACKGROUND On 11 December 2013, 3 clustered cases of hepatitis E were reported on a French coastal island. Individuals had taken part in a wedding meal that included a spit-roasted piglet. The piglet had been stuffed with a raw stuffing partly made from the liver. Investigations were carried out to identify the vehicle of contamination and evaluate the dispersion of the hepatitis E virus (HEV) in the environment. METHODS A questionnaire was administered to 98 wedding participants who were asked to give a blood sample. Cases were identified by reverse transcription-polymerase chain reaction and serological tests. A retrospective cohort study was conducted among 38 blood-sampled participants after the exclusion of 14 participants with evidence of past HEV infection. Relative risks (RR) and 95% confidence intervals were calculated based on food consumed at the wedding meal using univariate and multivariable Poisson regressions. Phylogenetic analyses were performed to compare the clinical HEV strains. Strains were detected in the liquid manure sampled at the farm where the piglet was born and in the untreated island wastewater. RESULTS Seventeen cases were identified, 70.6% were asymptomatic. Acute HEV infection was independently associated with piglet stuffing consumption (RR = 1.69 [1.04-2.73], P = .03). Of clinical strains from the index cases, veterinary and environmental HEV strains were identical. CONCLUSIONS Our investigation attributed this large HEV outbreak to the consumption of an undercooked pig liver-based stuffing. After infection, the cases became a temporary reservoir for HEV, which was detected in the islands untreated wastewater.

Le botulisme infantile en France, 1991–2009

Infant botulism is caused by the ingestion of spores of Clostridium botulinum and affects newborns and infants under 12 months of age. Ingested spores multiply and produce botulinum toxin in the digestive tract, which then induces clinical symptoms. A single French case was described in the literature prior to 1991. We describe the cases of infant botulism identified in France between 1991 and 2009. All clinical suspicions of botulism must be declared in France. Biological confirmation of the disease is provided by the National reference laboratory for anaerobic bacteria and botulism at the Pasteur Institute. During this period, 7 cases of infant botulism were identified, 1 per year from 2004 to 2008 and 2 in 2009. The median age of affected infants was 119 days and all were female. All infants presented with constipation and oculomotor symptoms. All were hospitalized and required mechanical ventilation. The infants recovered from their botulism. The diagnosis of infant botulism was biologically confirmed for all patients. One 4-month-old infant was treated with a single dose of the human-derived botulism antitoxin specific for infant botulism types A and B (BabyBIG®). The infants all had different feeding habits ranging from exclusive breast feeding to a mix of formula feeding and solid food consumption. The consumption of honey, the only documented risk food for this disease, was reported for 3 of the infants. The honey had been placed on the pacifier of 2 infants and directly in the mouth of the 3rd by the mother. Infant botulism, a form of botulism that was previously rarely recognized in France, has been reported more frequently during the last 6 years. This disease remains rare but nonetheless severe. In light of recent epidemiological data, efforts to raise awareness among parents of infants and health professionals on the danger of infant botulism and particularly, its association with honey consumption seems necessary.

Associations of Age and Sex With the Clinical Outcome and Incubation Period of Shiga toxin–producing Escherichia coli O104:H4 Infections, 2011

We pooled data on adults who reported diarrhea or developed life-threatening hemolytic uremic syndrome (HUS) in any of 6 closed cohorts from 4 countries (1 cohort each in Denmark, France, and Sweden and 3 in Germany) that were investigated during a large outbreak of Shiga toxin-producing Escherichia coli (STEC) O104:H4 infection in 2011. Logistic regression and Weibull regression for interval censored data were used to assess the relation of age and sex with clinical outcome and with incubation period. Information on the latter was used in a nonparametric back-projection context to estimate when adult cases reported in Germany were exposed to STEC O104:H4. Overall, data from 119 persons (median age, 49 years; 80 women) were analyzed. Bloody diarrhea and HUS were recorded as the most severe outcome for 44 and 26 individuals, respectively. Older age was significantly associated with bloody diarrhea but not with HUS. Woman had nonsignificantly higher odds for bloody diarrhea (odds ratio = 1.81) and developing HUS (odds ratio = 1.83) than did men. Older participants had a statistically significantly reduced incubation period. The shortest interval that included 75% of exposures in adults spanned only 12 days and preceded outbreak detection. In conclusion, the frequency of bloody diarrhea but not of HUS and the length of the incubation period depended on the age of individuals infected with STEC O104:H4. A large number of people were exposed to STEC O104:H4 for a short period of time.

Assessment and proposal of a new combination of screening criteria for hepatitis C in France.

BACKGROUND The current French hepatitis C virus infection screening programme is not yet reaching all populations at risk. In order to better identify individuals that would benefit from a screening test, we investigated an expanded combination of personal characteristics as potential screening criteria for this infection. METHODS We constructed two multiple-regression models predicting hepatitis C antibody seropositivity using the population sample from the 2004 French national hepatitis C antibody seroprevalence survey (SPS) (n = 14 416): one representing current screening guidelines and another constructed from personal characteristics collected for the SPS. Performance of the two predictive models was statistically compared and we internally validated the better performing model. RESULTS The expanded screening criteria model better discriminated seropositive and seronegative individuals [area under the ROC curve (AUC) 0.869 (95% CI 0.861-0.873)] than the current screening guidelines model [AUC 0.821 (95% CI 0.810-0.824)]. This performance difference was statistically significant (P < 0.00001). The expanded criteria model contains the variables age, sex, pre-1992 blood transfusion, intra-venous drug use, receipt of medical welfare for precarious individuals, previous surgeries, illicit nasal drug use, previous hepatitis C screening, tattoo, raised alanine aminotransferase level and birth in a hepatitis C high/moderate-prevalence country. CONCLUSION Results indicate that an expanded combination of screening criteria better predicted hepatitis C antibody status and thus individuals needing screening than the current French-screening guidelines. The proposed combination of screening criteria could more effectively target hepatitis C risk-populations in France and could serve as the basis for a decision-making screening tool for the general population.

Family outbreak of Shiga toxin-producing Escherichia coli O123:H-, France, 2009.

To the Editor: Shiga toxin–producing Escherichia coli (STEC) is a major cause of foodborne disease in industrialized countries. We present results of the investigation of a family outbreak in France caused by a rare STEC serotype. Surveillance of STEC infections in France since 1996 has been based on national surveillance of STEC-related pediatric hemolytic uremic syndrome (HUS) (1). On February 11, 2009, two cases of diarrhea were reported to a surveillance coordinator: 1 in a child with HUS and the other in that child’s sibling. The 2 siblings, 2 and 6 years of age, had diarrhea beginning on February 4 and 5, 2009. Bloody diarrhea developed in the younger child, and HUS was diagnosed on February 9. The older child had nonbloody diarrhea for 3 days and abdominal pain. Questioning of the patients’ parents identified no recent history of travel, contact with farm animals, or outdoor bathing. A food history indicated that the 2 patients had shared an undercooked ground beef burger 4–5 days before symptom onset. The patients’ parents also ate burgers from the same package (box); they did not report any gastrointestinal symptoms. Fecal specimens of the patients were tested for STEC by direct PCR for STEC genes (stx); after which culture and identification of stx1, stx2, eae, and ehxA (hlyA) virulence genes; and serotyping with a panel of 22 serum samples were conducted as described (1,2). Molecular serotyping was subsequently conducted on nonagglutinating strains by using the rfb–restriction fragment length polymorphism technique for O antigen (3) and sequencing of the fliC gene for H antigen (4). A trace-back investigation was conducted for the implicated beef burgers, which were obtained from a box of 10, frozen, 100-g ground beef burgers purchased in late January 2009. The remaining beef burger in the box from which the patients had eaten a beef burger was obtained from the family’s freezer for microbiologic testing. Stored production samples from the implicated batch underwent microbiologic testing. After broth enrichment, ground beef samples were tested by PCR for stx and eae virulence genes and O antigens of serotypes O157, O26, O145, O103, and O111 (2,5,6). Subsequently, strains isolated from stx-positive and eae-positive enrichment broths were biochemically tested and underwent serotyping and PCR identification of virulence genes. Genetic relatedness of clinical and ground beef STEC strains was studied by using pulsed-field gel electrophoresis with Xbal as described (7). A nonmotile strain of STEC stx2 eae ehxA, which was not serotypeable by the panel of 22 serum samples, was identified in fecal samples from patients and in the remaining ground beef. Molecular serotyping of clinical isolates and an isolate from the beef identified a strain of STEC O123:H2. Analysis by pulsed-field gel electrophoresis indicated that the clinical and meat isolates were genetically related (Figure). The level of STEC contamination in the meat was 30–40 CFU/g. All stored meat production samples tested were negative for STEC. Figure Representative XbaI pulsed-field gel electrophoresis patterns of Shiga toxin–producing Escherichia coli (STEC) O123:H– strains isolated from patient fecal samples and strains isolated from ground beef obtained from patients’ home, ... A clinical strain and a ground beef STEC strain were sent to the World Health Organization Collaborating Centre for Reference and Research on Escherichia and Klebsiella in Copenhagen, Denmark, in December 2009 for analysis. The clinical strain was confirmed as STEC O123:H–, and the meat strain was confirmed as a nonmotile STEC rough type by serum agglutination. Both strains had virulence genes stx2a, eae, and ehxA (F. Scheutz, pers. comm.). We identified a family outbreak of STEC O123:H– stx2a, eae ehxA infections associated with ingestion of undercooked ground beef. No similar cases of STEC infection were identified by active case finding. This serotype is rarely described as a cause of human clinical infection. No human isolate of serotype O123:H– is recorded in the database of the World Health Organization Collaborating Centre for Reference and Research on Escherichia and Klebsiella (F. Scheutz, pers. comm.). Two strains of STEC O123:H– stx2d were isolated from asymptomatic persons in Germany during 1996–2000 (8). A study in Australia in 2003 reported using a strain of O123:H– stx1 stx2 ehxA from Switzerland that had been isolated from a person with diarrhea (9). We report foodborne transmission of STEC O123:H– that resulted in a cluster of clinical cases of infection. Eating ground beef is a well-established mode of STEC transmission, particularly for serotype O157:H7. STEC serotype O123:H– has been isolated from feces of healthy lambs and sheep in Spain (10) and in southwestern Australia (9) and is considered to be among the predominant ovine STEC serotypes in these countries. This family outbreak shows that STEC serotype O123:H–, albeit rarely described as causing human illness, can cause severe human infection. This serotype can also cause clusters of STEC infections and be transmitted by ingestion of undercooked ground beef.

Outbreak of Q fever, Florac, Southern France, Spring 2007

INTRODUCTION In May 2007, five patients with Q fever-like symptoms were reported in an agricultural educational center in the rural southern French town of Florac. An investigation was undertaken to identify the outbreak source and risk factors for infection, and to implement control measures. MATERIALS AND METHODS We undertook active case finding. Patients were defined as individuals with an unexplained fever of ≥38.5°C who lived in, worked in, or visited Florac between April 1 and June 30, 2007. Patients were confirmed by a positive Q fever serology test. A cross-sectional survey with a seroprevalence component was carried out in the educational center and surrounding area. A standardized questionnaire on known risk factors for the infection was used and serological testing was carried out on finger prick blood specimens from participants. The veterinary services investigated local herds within a 5-mile radius using polymerase chain reaction and serological tests. RESULTS One hundred twenty-two people were included in the cross-sectional survey. Eighteen serologically confirmed acute cases were identified, of whom 12 were from the educational center. The statistical analysis showed an independent association between acute infection and living or working near an area where manure had been spread (p = 0.0.042) and male gender (p = 0.022). Frequenting the educational centers canteen was also associated with infection (p = 0.008) among staff and students. The veterinary investigations identified 11 of the 26 tested flocks of goats and sheep as seropositive for Coxiella burnetii, including 2 ovine flocks located northwest of Florac that had high shedding levels of the bacterium. DISCUSSION The observed excess of cases of Q fever in Florac, an area endemic for this infection, in spring 2007 could be explained by an aerial transmission from infectious ovine flocks situated close to the town. All local herd owners were re-educated about the risks and prevention practices for Q fever.

Hemolytic uremic syndrome due to Shiga toxin-producing Escherichia coli infection

The leading cause of hemolytic uremic syndrome (HUS) in children is Shiga toxin-producing Escherichia coli (STEC) infection, which has a major outbreak potential. Since the early 2010s, STEC epidemiology is characterized by a decline of the historically predominant O157 serogroup and the emergence of non-O157 STEC, especially O26 and O80 in France. STEC contamination occurs through the ingestion of contaminated food or water, person-to-person transmission, or contact with ruminants or their contaminated environment. The main symptom is diarrhea, which is bloody in about 60% of patients and occurs after a median incubation period of three days. Shiga toxins released by STEC induce a cascade of thrombogenic and inflammatory changes of microvascular endothelial cells. HUS is observed in 5-15% of STEC infection cases, defined by the triad of mechanical hemolytic anemia, thrombocytopenia, and acute renal injury. The diagnosis of STEC infection relies on biological screening for Shiga toxins and STEC in stools and serology. Treatment of STEC-HUS is mainly symptomatic, as no specific drug has proved effective. The effect of antibiotics in STEC infection and STEC-HUS remains debated; however, some bacteriostatic antibiotics might have a beneficial effect. Proofs of evidence of a benefit from complement blockade therapy in STEC-HUS are also lacking. Clinical and bacteriological STEC-HUS surveillance needs to be continued. Ongoing prospective studies will document the role of bacteriostatic antibiotics in STEC infection and STEC-HUS, and of complement blockade therapy in STEC-HUS.

Surveillance du syndrome hémolytique et urémique chez les enfants de moins de 15 ans en France, 1996–2011

Sources : Institut de veille sanitaire, Saint-Maurice (E. Espié, V. Vaillant), Cellule interrégionale d’épidémiologie du Nord (S. Haeghebaert), Centre national de référence des E. coli et Shigella, Institut Pasteur, Paris (F. Grimont), Laboratoire associé au Centre national de référence des E. coli et Shigella, Hôpital Robert Debré, Paris (P. Mariani-Kurkdjian), Services de néphrologie pédiatrique des Centres hospitaliers de : Amiens, Angers, Angoulême, Annecy, Besançon, Bordeaux, Brest, Clermont-Ferrand, Dijon, Kremlin-Bicêtre, Grenoble, Lille, Lisieux, Lyon (Debrousse, E. Herriot), Marseille, Montpellier, Nancy, Nantes, Nice, Paris (Necker-Enfants Malades, R. Debré, Trousseau), Reims, Rennes, Rouen, Saint-Etienne, Strasbourg, Toulouse, Tours. Synthèse réalisée par : E. Espié, Institut de veille sanitaire Mots clés : syndrome hémolytique et urémique (SHU), Escherichia coli producteurs de shigatoxines (STEC), épidémiologie, France. Courriel : e.espie@invs.sante.fr