Hospital-acquired infections caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli are a global problem. Healthy people can carry ESBL-producing E. coli in their intestines; thus, E. coli from healthy people can potentially cause hospital-acquired infections. Therefore, the transmission routes of ESBL-producing E. coli from healthy persons should be determined.A foodborne outbreak of human norovirus GII (HuNoV) occurred at a restaurant in Shizuoka, Japan, in 2018. E. coli O25:H4 was isolated from some of the HuNoV-infected customers. Pulsed-field gel electrophoresis showed that these E. coli O25:H4 strains originated from one clone. Because the only epidemiological link among the customers was eating food from this restaurant, the customers were concurrently infected with E. coli O25:H4 and HuNoV GII via the restaurant food. Whole-genome analysis revealed that the E. coli O25:H4 strains possessed genes for regulating intracellular iron and expressing the flagellum and flagella. Extraintestinal pathogenic E. coli often express these genes on the chromosome. Additionally, the E. coli O25:H4 strains had plasmids harboring nine antimicrobial-resistance genes. These strains harbored ESBL-encoding blaCTX-M-14 genes on two loci of the chromosome and had higher ESBL activity. Multilocus sequence typing and fimH subtyping revealed that the E. coli O25:H4 strains from the outbreak belonged to the subclonal group, ST131-fimH30R, which has been driving ESBL epidemics in Japan.Because the E. coli O25:H4 strains isolated in the outbreak belonged to a subclonal group spreading in Japan, foods contaminated with ESBL-producing E. coli might contribute to spreading these strains among healthy persons. The isolated E. coli O25:H4 strains produced ESBL and contained plasmids with multiple antimicrobial-resistance genes, which may make it difficult to select antimicrobials for treating extraintestinal infections caused by these strains.
This study aimed at investigating antimicrobial resistance (AMR) profile of
Vibrio parahaemolyticus (V. parahaemolyticus).
The bacteria were isolated from wild-caught and farmed Japanese horse mackerel (
Trachurus japonicus
), and examined for the antimicrobial drug resistance. Furthermore, the serotype, and the genes of thermostable direct hemolysin (
tdh
) and cholera toxin transcriptional activator (
toxR
) of the isolates were investigated by using a serotype testing kit and PCR method. Eighty-eight and 126
V. parahaemolyticus
strains were isolated from wild-caught and farmed Japanese horse mackerel, respectively. Ten and 18 distinct serotypes were detected from wild-caught and farmed Japanese horse mackerel. All strains were negative for
tdh
genes but positive for
toxR
genes. Resistances to ampicillin (ABP) and to both ABP and fosfomycin (FOM) were observed in 54 and 23 strains from the wild-caught fish, while those resistant strains from farm fish were 112 and 7 strains. Multidrug-resistance to three or four drugs including ABP was observed in one or two strains from the wild-caught fish.
These results strongly suggest that the environmental exposure of antimicrobial drugs results in the spread of resistant genes in Japanese horse mackerel. This study highlights the need for monitoring the spread of resistance genes to the human intestinal flora as well as to other bacteria in the environment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.