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Dissemination of extended-spectrum-cephalosporin (ESC)-resistant Salmonella, especially extended-spectrum-β-lactamase (ESBL)-producing Salmonella, is a concern worldwide. Here, we assessed Salmonella carriage by food workers in Japan to clarify the prevalence of ESC-resistant Salmonella harboring blaCTX-M. We then characterized the genetic features, such as transposable elements, of blaCTX-M-harboring plasmids using whole-genome sequencing. A total of 145,220 stool samples were collected from food workers, including cooks and servers from several restaurants, as well as food factory workers, from January to October 2017. Isolated salmonellae were subjected to antimicrobial susceptibility testing (disk diffusion method), and whole-genome sequencing was performed for Salmonella strains harboring blaCTX-M. Overall, 164 Salmonella isolates (0.113%) were recovered from 164 samples, from which we estimated that at least 0.113% (95% confidence interval [CI]: 0.096 to 0.132%) of food workers may carry Salmonella. Based on this estimation, 3,473 (95% CI = 2,962 to 4,047) individuals among the 3,075,330 Japanese food workers are likely to carry Salmonella. Of the 158 culturable isolates, seven showed resistance to ESCs: three isolates harbored blaCMY-2 and produced AmpC β-lactamase, while four ESBL-producing isolates harbored blaCTX-M-14 (n = 1, Salmonella enterica serovar Senftenberg) or blaCTX-M-15 (n = 3, S. enterica serovar Haardt). blaCTX-M-15 was chromosomally located in the S. Haardt isolates, which also contained ISEcp1, while the S. Senftenberg isolate contained an IncFIA(HI1)/IncHI1A/IncHI1B(R27) hybrid plasmid carrying blaCTX-M-14 along with ISEcp1. This study indicates that food workers may be a reservoir of ESBL-producing Salmonella and associated genes. Thus, these workers may contribute to the spread of blaCTX-M via plasmids or mobile genetic elements such as ISEcp1. IMPORTANCE Antimicrobial-resistant Salmonella bacteria arise in farm environments through imprudent use of antimicrobials. Subsequently, these antimicrobial-resistant strains, such as extended-spectrum-β-lactamase (ESBL)-producing Salmonella, may be transmitted to humans via food animal-derived products. Here, we examined Salmonella carriage among food handlers in Japan. Overall, 164 of 145,220 fecal samples (0.113%) were positive for Salmonella. Among the 158 tested isolates, four were identified as ESBL-producing isolates carrying ESBL determinants blaCTX-M-15 or blaCTX-M-14. In all cases, the genes coexisted with ISEcp1, regardless of whether they were located on the chromosome or on a plasmid. Our findings suggest that food workers may be a reservoir of ESBL-producing strains and could contribute to the spread of resistance genes from farm-derived Salmonella to other bacterial species present in the human gut.

Dissemination of extended-spectrum-cephalosporin (ESC)-resistant Salmonella, especially extended-spectrum-β-lactamase (ESBL)-producing Salmonella, is a concern worldwide. Here, we assessed Salmonella carriage by food workers in Japan to clarify the prevalence of ESC-resistant Salmonella harboring bla(CTX-M). We then characterized the genetic features, such as transposable elements, of bla(CTX-M)-harboring plasmids using whole-genome sequencing. A total of 145,220 stool samples were collected from food workers, including cooks and servers from several restaurants, as well as food factory workers, from January to October 2017. Isolated salmonellae were subjected to antimicrobial susceptibility testing (disk diffusion method), and whole-genome sequencing was performed for Salmonella strains harboring bla(CTX-M). Overall, 164 Salmonella isolates (0.113%) were recovered from 164 samples, from which we estimated that at least 0.113% (95% confidence interval [CI]: 0.096 to 0.132%) of food workers may carry Salmonella. Based on this estimation, 3,473 (95% CI = 2,962 to 4,047) individuals among the 3,075,330 Japanese food workers are likely to carry Salmonella. Of the 158 culturable isolates, seven showed resistance to ESCs: three isolates harbored bla(CMY-2) and produced AmpC β-lactamase, while four ESBL-producing isolates harbored bla(CTX-M-14) (n = 1, Salmonella enterica serovar Senftenberg) or bla(CTX-M-15) (n = 3, S. enterica serovar Haardt). bla(CTX-M-15) was chromosomally located in the S. Haardt isolates, which also contained ISEcp1, while the S. Senftenberg isolate contained an IncFIA(HI1)/IncHI1A/IncHI1B(R27) hybrid plasmid carrying bla(CTX-M-14) along with ISEcp1. This study indicates that food workers may be a reservoir of ESBL-producing Salmonella and associated genes. Thus, these workers may contribute to the spread of bla(CTX-M) via plasmids or mobile genetic elements such as ISEcp1. IMPORTANCE Antimicrobial-resistant Salmonella bacteria arise in farm environments through imprudent use of antimicrobials. Subsequently, these antimicrobial-resistant strains, such as extended-spectrum-β-lactamase (ESBL)-producing Salmonella, may be transmitted to humans via food animal-derived products. Here, we examined Salmonella carriage among food handlers in Japan. Overall, 164 of 145,220 fecal samples (0.113%) were positive for Salmonella. Among the 158 tested isolates, four were identified as ESBL-producing isolates carrying ESBL determinants bla(CTX-M-15) or bla(CTX-M-14). In all cases, the genes coexisted with ISEcp1, regardless of whether they were located on the chromosome or on a plasmid. Our findings suggest that food workers may be a reservoir of ESBL-producing strains and could contribute to the spread of resistance genes from farm-derived Salmonella to other bacterial species present in the human gut.

Tokyo Gas Yokosuka Power Station is an IPP combined cycle power plant supplied by Fuji Electric Systems Co., Ltd. in Japan. This power plant applies the following advanced Water Chemistry that is mainly intended to minimize environmental impact. The plant has been in commercial operation since June 2006.

The diffusion bonding has been applied to the dissimilar metal joining of aluminum bronze (JIS C-6191) to austenitic stainless steel (JIS SUS 316L) which is very difficult to bond by conventional welding techniques. The microstructure of the bond zone and fractured surface of the joints have been examined to get better understanding of important factors that determine the strength of the joints. Results obtained are summarized as follows.In the diffusion bonding without insert-metal the maximum tensile strength of the joint, which was obtained at the bonding temperature of 1273K, was about 300MPa much lower than the strength of base metals. In this joint the stainless steel adjacent to the bonding interface undertook transformation from austenite to ferrite owing to the increase in the concentration of aluminum (ferrite former element) supplied from aluminum bronze. Along the grain boundaries in the transformed layer, an intermetallic compound composed of Al, Cu and Ni was observed. When the joint bonded at 1273K was subjected to a tensile test, crack propagated chiefly along the intermetallic compound. Therefore, the intermetallic compound was considered to be an important factor that depressed the strength of the joint.In order to improve the strength of the joints, copper foil and iron foil as the insert-metal were used. The formation of the intermetallic compound was suppressed considerably by using the insert-metal. However, when iron insert-metal was applied, it was very difficult to attain intimate contact between stainless steel and the insert-metal, because the flow stress of the insert-metal was much higher than that of aluminum bronze at bonding temperatures adopted. On the other hand, when copper insert-metal was applied. The tensile strength of the joint was considerably increased compared with that of the joint without insert-metal. The maximum tensile strength of 400MPa was obtained at the bonding temperature of 1313 K by using the copper insert-metal 50 μm thick.

Organ formation has been studied with lateral buds excised from bulbs of Iris hollandica cv.‘Wedgwood.’The buds were cultured in vitro on the medium of modified Kano, Neergarrd and Morel. Adventitious bud formation of explants was induced on the medium containing both NAA and BA, but root formation was suppressed. Root formation was observed on the medium containing NAA alone as a plant growth regulator. High concentration of mineral salt favoured the growth of explants, and better results were obtained on the medium based on Morel or modified Kano. Peptone added into modified Kano′s medium inhibited the growth of explants at 2g/l and higher concentrations. The growth of explants was good at pH 5.0 and 6.0. The optimal concentrations for agar and sucrose were 2g/l and 2-4%, respectively.