Research Publications (Food Safety)

Most infant botulism cases worldwide are due to botulinum toxin types A and B. Rarely, Clostridium botulinum strains that produce two serotypes (Ab, Ba, and Bf) have also been isolated from infant botulism cases. This is the first reported case of infant botulism due to C. botulinum type Af worldwide.

An outbreak of human botulism was due to consumption of ham containing botulinum neurotoxins B and E. A Clostridium botulinum type E strain isolated from ham was assigned to a new subtype (E12) based on bont/E gene sequencing and belongs to a new multilocus sequence subtype, as analyzed by whole-genome sequencing.

We evaluated the use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MS) for the identification of Vibrio cholerae. MS identified all 42 isolates of V. cholerae O1 and O139 and 7 of 9 non-O1/O139 isolates. MS correctly discriminated between all Aeromonas and V. cholerae isolates. Overall, MS performed as well as or better than biochemical methods.

The genus Yersinia is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus.

An occurrence of Vibrio cholerae non-O1/O139 gastroenteritis in the U.S. Gulf Coast is reported here. Genomic analysis revealed that the isolate lacked known virulence factors associated with the clinical outcome of a V. cholerae infection but did contain putative genomic islands and other accessory virulence factors. Many of these factors are widespread among environmental strains of V. cholerae, suggesting that there might be additional virulence factors in non-O1/O139 V.

Yersinia enterocolitica and Yersinia pseudotuberculosis, the two Yersinia species that are enteropathogenic for humans, are distributed worldwide and frequently cause diarrhea in inhabitants of temperate and cold countries. Y. enterocolitica is a major cause of foodborne disease resulting from consumption of contaminated pork meat and is further associated with substantial economic cost.

We describe a case of acute liver failure caused by echovirus 25 (E25) in a previously healthy 2-year-old boy. Initial serological studies were consistent with hepatitis A virus (HAV), with prozone phenomenon. The similarity of E25 to HAV may obscure accurate diagnosis in some cases of hepatitis.

Since its first identification, the epizootic avian influenza A H7N9 virus has continued to cause infections in China. Two waves were observed during this outbreak. No cases were reported from Guangdong Province during the first wave, but this province became one of the prime outbreak sites during the second wave.

We report two cases of infantile diarrhea due to multidrug-resistant, NDM-1 metallo-β-lactamase-producing Salmonella enterica serovar Agona from Pakistan. This study alerts toward possible risk of NDM-1 transmission to enteric fever pathogens and encourages microbiologists to consider active screening of carbapenem resistance in nontyphoidal Salmonella isolates.

Retrospectively, we investigated the epidemiology of a massive Salmonella enterica serovar Typhi outbreak in Zambia during 2010 to 2012. Ninety-four isolates were susceptibility tested by MIC determinations. Whole-genome sequence typing (WGST) of 33 isolates and bioinformatic analysis identified the multilocus sequence type (MLST), haplotype, plasmid replicon, antimicrobial resistance genes, and genetic relatedness by single nucleotide polymorphism (SNP) analysis and genomic deletions.

A retrospective investigation was performed to evaluate whole-genome sequencing as a benchmark for comparing molecular subtyping methods for Salmonella enterica serotype Enteritidis and survey the population structure of commonly encountered S. enterica serotype Enteritidis outbreak isolates in the United States. A total of 52 S.