Listeriosis Outbreaks and Associated Food Vehicles, United States, 1998-2008

Emerging Infectious Diseases (Impact Factor: 6.75). 01/2013; 19(1):1-9. DOI: 10.3201/eid1901.120393
Source: PubMed


Listeria monocytogenes, a bacterial foodborne pathogen, can cause meningitis, bacteremia, and complications during pregnancy. This report summarizes listeriosis outbreaks reported to the Foodborne Disease Outbreak Surveillance System of the Centers for Disease Control and Prevention during 1998-2008. The study period includes the advent of PulseNet (a national molecular subtyping network for outbreak detection) in 1998 and the Listeria Initiative (enhanced surveillance for outbreak investigation) in 2004. Twenty-four confirmed listeriosis outbreaks were reported during 1998-2008, resulting in 359 illnesses, 215 hospitalizations, and 38 deaths. Outbreaks earlier in the study period were generally larger and longer. Serotype 4b caused the largest number of outbreaks and outbreak-associated cases. Ready-to-eat meats caused more early outbreaks, and novel vehicles (i.e., sprouts, taco/nacho salad) were associated with outbreaks later in the study period. These changes may reflect the effect of PulseNet and the Listeria Initiative and regulatory initiatives designed to prevent contamination in ready-to-eat meat and poultry products.

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Available from: Benjamin Silk, Apr 15, 2014
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    • "Noninvasive listeriosis is often associated with febrile gastroenteritis and sometimes with cutaneous forms, as observed in veterinary surgeons coming into direct contact with aborted foetuses from livestock [8] [9]. The disease is usually vertically transmitted during pregnancy or acquired by the consumption of contaminated food, particularly fresh and ready-to-eat products that are not heated before consumption [10] [11]. "
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    ABSTRACT: We investigated the pathogenicity, invasiveness, and genetic relatedness of 17 clinical Listeria monocytogenes stains isolated over a period of nine years (2006–2014). All isolates were phenotypically characterised and growth patterns were determined. The antimicrobial susceptibility of L. monocytogenes isolates was determined in E-tests. Invasion assays were performed with epithelial HeLa cells. Finally, L. monocytogenes isolates were subtyped by PFGE and MLST. All isolates had similar phenotypic characteristics ( β -haemolysis and lecithinase activity), and three types of growth curve were observed. Bacterial recovery rates after invasion assays ranged from 0.09% to 7.26% (1.62 ± 0.46). MLST identified 11 sequence types (STs), and 14 PFGE profiles were obtained, indicating a high degree of genetic diversity. Genetic studies unequivocally revealed the occurrence of one outbreak of listeriosis in humans that had not previously been reported. This outbreak occurred in October 2009 and affected three patients from neighbouring towns. In conclusion, the molecular epidemiological analysis clearly revealed a cluster (three human cases, all ST1) of not previously reported listeriosis cases in northwestern Spain. Our findings indicate that molecular subtyping, in combination with epidemiological case analysis, is essential and should be implemented in routine diagnosis, to improve the tracing of the sources of outbreaks.
    Full-text · Article · Jul 2015 · BioMed Research International
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    • "Listeria monocytogenes is a non-spore forming, facultative anaerobic Gram-positive bacterium, widespread in the environment (Farber and Peterkin 1991). The bacterium is a serious pathogen responsible annually for 1 662 invasive infections and 266 related deaths in the United States (Cartwright et al. 2013). L. monocytogenes was identified for the first time in 1926 as a cause of monocytosis in rodents.Serotypes 1/2a, 1/2c and 3a (lineage II) have been associated with sporadic cases of listeriosis, whereas serotypes 4a and 4c are generally isolated from animals (Vhzquez-Boland et al. 2001). "
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    ABSTRACT: Animals are important reservoir of Listeria monocytogenes, a pathogen causing serious infections in both humans and livestock. However, data on invasiveness of L. monocytogenes strains of animal origin is very scarce. Ability of 18 L. monocytogenes strains of animal origin to invade HT-29 cells was investigated. Plaque forming assay was used to assess invasiveness and ability of the pathogen to spread in the cell line. Almost 40% of L. monocytogenes strains were weakly invasive. It was shown that strains from serogroup 4b exhibited the highest invasiveness, whereas serogroup 1/2b consisted of strains of invasiveness below 0.0001%. Analysis of translated inlA and inlB gene sequences revealed no premature stop codons. Lineage-specific mutations in low invasive strains were identified within inlA and inlB sequences. Our results demonstrate high incidence of low invasive animal L. monocytogenes strains, which may be at least partly explained by unique point mutations in the InlA and InlB.
    Full-text · Article · Jan 2015
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    • "It can also cross the blood-tissue barrier which allows the bacteria to infect organs such as the brain or uterus, where it can cause severe life-threatening infections such as meningitis, encephalitis, spontaneous abortion, or miscarriage. Although the incidence of human listeriosis is comparatively low, at up to 30% it has the third highest mortality rate of all food borne pathogens (EFSA, 2014) and immunocompromised individuals are particularly at risk (Vazquez-Boland et al., 2001; Cartwright et al., 2013). According to the most recent EU data, the mortality rate was 12.1% for the 1642 cases reported in the year 2012 (EFSA, 2014). "
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    ABSTRACT: Although rates of listeriosis are low in comparison to other foodborne pathogenic illness, listeriosis poses a significant risk to human health as the invasive form can have a mortality rate as high as 30%. Food processors, especially those who produce ready-to-eat (RTE) products, need to be vigilant against Listeria monocytogenes, the causative pathogen of listeriosis, and as such, the occurrence of L. monocytogenes in food and in the food processing environment needs to be carefully monitored. To examine the prevalence and patterns of contamination in food processing facilities in Ireland, 48 food processors submitted 8 samples every 2 months from March 2013 to March 2014 to be analyzed for L. monocytogenes. No positive samples were detected at 38% of the processing facilities tested. Isolates found at the remaining 62% of facilities were characterized by serotyping and Pulsed Field Gel Electrophoresis (PFGE). A general L. monocytogenes prevalence of 4.6% was seen in all samples analyzed with similar rates seen in food and environmental samples. Differences in prevalence were seen across different food processors, food sectors, sampling months etc. and PFGE analysis allowed for the examination of contamination patterns and for the identification of several persistent strains. Seven of the food processing facilities tested showed contamination with persistent strains and evidence of bacterial transfer from the processing environment to food (the same pulsotype found in both) was seen in four of the food processing facilities tested.
    Full-text · Article · Aug 2014 · Frontiers in Microbiology
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