Estimates of foodborne illness can be used to direct food safety policy and interventions. We used data from active and passive surveillance and other sources to estimate that each year 31 major pathogens acquired in the United States caused 9.4 million episodes of foodborne illness (90% credible interval [CrI] 6.6–12.7 million), 55,961 hospitalizations (90% CrI 39,534–75,741), and 1,351 deaths (90% CrI 712–2,268). Most (58%) illnesses were caused by norovirus, followed by nontyphoidal Salmonella spp. (11%), Clostridium perfringens (10%), and Campylobacter spp. (9%). Leading causes of hospitalization were nontyphoidal Salmonella spp. (35%), norovirus (26%), Campylobacter spp. (15%), and Toxoplasma gondii (8%). Leading causes of death were nontyphoidal Salmonella spp. (28%), T. gondii (24%), Listeria monocytogenes (19%), and norovirus (11%). These estimates cannot be compared with prior (1999) estimates to assess trends because different methods were used. Additional data and more refined methods can improve future estimates.

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Foodborne Illness Acquired in the United States—Major Pathogens

Evolution of Protein Molecules

Publisher Summary Recent advances in the biochemistry of microorganisms have revealed that cell-component analysis can be effectively applied to bacterial systematics, providing the basis of chemotaxonomy. Analyses of cell components are coming to be essential tools not only for bacterial classification but also for identification. The sequence of chromosomal DNA holds the essential genetic information for an organism. Phylogenetic relationships are often examined using data on nucleotide sequences of ribosomal RNA. However, it is still impossible to determine the sequences of large polynucleotides for the number of organisms sufficient for taxonomic purposes. DNA (RNA) homologies, which have been applied to various kinds of bacteria, present useful information on bacterial systematics. Homology indices are values used in comparing microorganisms. DNA homology data contribute to the clarification, not only of the relatedness of two organisms, but also of the evaluation of phenotypic characteristics.

4 Lipid and Cell-Wall Analysis in Bacterial Systematics

Cytotoxic T lymphocytes (CTLs) specific for conserved viral antigens can respond to different strains of virus, in contrast to antibodies, which are generally strain-specific. The generation of such CTLs in vivo usually requires endogenous expression of the antigen, as occurs in the case of virus infection. To generate a viral antigen for presentation to the immune system without the limitations of direct peptide delivery or viral vectors, plasmid DNA encoding influenza A nucleoprotein was injected into the quadriceps of BALB/c mice. This resulted in the generation of nucleoprotein-specific CTLs and protection from a subsequent challenge with a heterologous strain of influenza A virus, as measured by decreased viral lung titers, inhibition of mass loss, and increased survival.

https://science.sciencemag.org/content/sci/259/5102/1745.full.pdf

Heterologous protection against influenza by injection of DNA encoding a viral protein

Listeria monocytogenes, a food-borne pathogen.

In Los Angeles County, California, 142 cases of human listeriosis were reported from January 1 through August 15, 1985. Ninety-three cases (65.5 percent) occurred in pregnant women or their offspring, and 49 (34.5 percent) in nonpregnant adults. There were 48 deaths: 20 fetuses, 10 neonates, and 18 nonpregnant adults. Of the nonpregnant adults, 98 percent (48 of 49) had a known predisposing condition. Eighty-seven percent (81 of 93) of the maternal/neonatal cases were Hispanic. Of the Listeria monocytogenes isolates available for study, 82 percent (86 of 105) were serotype 4b, of which 63 of 86 (73 percent) were the same phage type. A case-control study implicated Mexican-style soft cheese (odds ratio, 5.5; 95 percent confidence interval, 1.2 to 24.8) as the vehicle of infection; a second case-control study showed an association with one brand (Brand A) of Mexican-style soft cheese (odds ratio, 8.5; 95 percent confidence interval, 2.4 to 26.2). Laboratory study confirmed the presence of L. monocytogenes serogroup 4b of the epidemic phage type in Brand A Mexican-style cheese. In mid-June, all Brand A cheese was recalled and the factory was closed. An investigation of the cheese plant suggested that the cheese was commonly contaminated with unpasteurized milk. We conclude that the epidemic of listeriosis was caused by ingestion of Brand A cheese contaminated by one phage type of L. monocytogenes serotype 4b.

Epidemic Listeriosis Associated with Mexican-Style Cheese

We studied the clinical characteristics and epidemiology of disease associated with a rare, unnamed halophilic lactose-fermenting Vibrio species in 39 persons from whom the organism had been isolated. Two distinct clinical presentations were seen. In the first, the illness began with septicemia, often within 24 hours after raw oysters had been eaten; 18 of 24 such patients had pre-existing hepatic disease, and 11 of the 24 died. In the second, there was a wound infection after exposure to seawater or an injury incurred during the handling of crabs; none of these persons had pre-existing hepatic disease, and one of 15 died. Most cases (85 per cent) occurred during relatively warm months (May to October) in men (90 per cent) 40 or more years of age (95 per cent). This Vibrio species is a pathogen and should be considered in the differential diagnosis of septicemia with secondary skin lesions and of wound infections after exposure to seawater. (N Engl J Med 300:1–5, 1979)

Disease caused by a marine Vibrio. Clinical characteristics and epidemiology.

Antisera and fluorescein isothiocyanate conjugates prepared for five strains of the Legionnaires bacteria were tested in both homologous and heterologous staining reactions with 10 isolates of the organism from patients in seven geographic areas. The strains were related but not identical as judged by the results of direct immunofluorescence staining. The conjugates were successfully used to detect Legionnaires disease bacteria in Formalin-fixed lung scrapings, in histological sections, and in fresh lung tissue obtained at biopsy or autopsy. In addition, the labeled antibodies are valuable for staining suspected cultures of the bacterium and for searching for the source of these organisms in soil, water, and other environmental niches. The reagents are highly specific for detecting the Legionnaires organism in clinical specimens. Images

Detection of Legionnaires disease bacteria by direct immunofluorescent staining.

Recent nemenclature changes symbols and abbreviations symbols for CDC "Groups" with published names evaluation of clinical bacterial specimen submitted for characterization and identification media and methods introduction to King's identification key gram-negative organisms - an approach to identification (guide to presumptive identification) media used for presumptive identification presumptive identification tables code book bacterial identification using King's key and "Round Table" charts key for identification of unusual pahtogenic gram-negative aerobic and facultatively anaerobic bacteria index to "Round Table" charts charts 1-46 descriptions of species bacterial identification by cellular fatty acid analysis introduction list of figures list of tables protocols names of fatty acids found in bacteria gas chromatograms and cellular fatty acid composition tables.

Identification of unusual pathogenic gram-negative aerobic and facultatively anaerobic bacteria

The Special Bacteriology Section of the Center for Disease Control has received 38 cultures of a halophilic bacterium which apparently unnamed. On the basis of the minimal characteristics of Vibrio species proposed by Hugh and Sakazaki, this bacterium belongs to the genus Vibrio. The unnamed species can be differentiated from Vibro parahaemolyticus by a lower tolerance for sodium chloride (NaC1) and the fermentation of lactose. The failure to ferment sucrose is an additional characteristic which differentiates these organisms from V. alginolyticus. Of 33 unnamed species strains tested, all were sensitive to penicillin, ampicillin, carbenicillin, cephalothin, chlorapmphenicol, gentamicin, tetracycline, rifampin, nitrofurantoin, and sulfisoxazole by agar diffusion and agar dilution tests. The sources of isolation of the cultures of the unnamed species suggest that it is a clinically important organism. Twenty strains were isolated remaining cultures were isolated from localized infections of the extremities. In contrast, only 2 of 60 cultures of V. parahaemolyticus and V. alginolyticus received in our laboratory as human isolates from extra-intestinal sources were isolated from blood.

Robert E. Weaver

Papers

Epidemic Listeriosis Associated with Mexican-Style Cheese

Disease caused by a marine Vibrio. Clinical characteristics and epidemiology.

Detection of Legionnaires disease bacteria by direct immunofluorescent staining.

Identification of unusual pathogenic gram-negative aerobic and facultatively anaerobic bacteria

Halophilic Vibrio species isolated from blood cultures.