Outbreak of Enterohemorrhagic Escherichia coli O157:H7 Infection Associated with Minced Meat Cutlets Consumption in Kanagawa, Japan.

An outbreak of enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection occurred in October 2016 in Kanagawa, Japan. A total of 61 patients and 17 asymptomatic cases of EHEC O157:H7 infection were confirmed by laboratory testing. Among them, 24 patients were hospitalized and 4 developed hemolytic-uremic syndrome. An epidemiological investigation revealed that this outbreak of EHEC O157:H7 infection was associated with the consumption of uncooked minced meat cutlets that were sold frozen at branches of a supermarket chain. The implicated uncooked meat cutlets were made of a mixture of minced beef, pork, onions, and eggs. All 40 meat cutlets tested from one particular batch were positive for EHEC O157:H7. The patterns observed on pulsed-field gel electrophoresis of strains isolated from the affected patients and meat cutlets were identical. The bacterial counts of EHEC O157:H7 and E. coli in meat cutlets ranged from 2.3 to 110 most-probable-number (MPN)/g and from 240 to 4,600 MPN/g, respectively. There are currently no national regulatory standards to ensure the safety of these types of meat products in Japan. Consumers should ensure that such products are cooked thoroughly and that safe food handling procedures are used to prevent infection.

Prevalence and Characteristics of Salmonella and Campylobacter in Retail Poultry Meat in Japan.

This study was performed to determine the prevalence, antimicrobial susceptibility, and genetic relatedness of Salmonella enterica subsp. enterica and Campylobacter spp. in poultry meat, and to analyze the association of genetic types of these bacteria with their geographical distribution and antimicrobial resistance profiles. Salmonella and Campylobacter isolates have been detected, respectively, in 54 and 71 samples out of 100 samples tested. Nine Salmonella serotypes were found, including S. enterica subsp. enterica serovar Infantis (33%), Schwarzengrund (12%), Manhattan (9%), and others. Campylobacter jejuni and C. coli were detected in 64 (64%) and 14 (14%) samples, respectively. S. enterica subsp. enterica isolates were very frequently resistant to tetracycline (78.3%) and streptomycin (68.3%). Many C. jejuni and C. coli isolates were resistant to sulfamethoxazole/trimethoprim (90.5%), nalidixic acid (47.3%), ampicillin (45.9%), and ciprofloxacin (40.5%). Cluster analysis was performed for the Salmonella isolates using pulsed-field gel electrophoresis (PFGE) data. For Campylobacter isolates, the cluster analysis was based on both PFGE and comparative genomic fingerprinting. The molecular typing results were compared with the information about antimicrobial resistance and geographical locations in which the poultry meat was produced. This analysis revealed that C. jejuni strains with a particular genotype and antimicrobial resistance profile are spreading in specific areas of Japan.

Mechanism of ultra low friction of multilayer graphene studied by coarse-grained molecular simulation.

Coarse-grained Metropolis Monte Carlo Brownian Dynamics simulations are used to clarify the ultralow friction mechanism of a transfer film of multilayered graphene sheets. Each circular graphene sheet consists of 400 to 1,000,000 atoms confined between the upper and lower sliders and are allowed to move in 3 translational and 1 rotational directions due to thermal motion at 300 K. The sheet-sheet interaction energy is calculated by the sum of the pair potential of the sp2 carbons. The sliding simulations are done by moving the upper slider at a constant velocity. In the monolayer case, the friction force shows a stick-slip like curve and the average of the force is high. In the multilayer case, the friction force does not show any oscillation and the average of the force is very low. This is because the entire transfer film has an internal degree of freedom in the multilayer case and the lowest sheet of the layer is able to follow the equipotential surface of the lower slider.

[Evaluation of selective plating media for the detection of heat- or freeze-injured Staphylococcus aureus].

The efficacy of Baird-Parker (BP) agar, mannitol-salt-egg yolk (MSEY) agar and mannitol salt (MS) agar in detecting Staphylococcus aureus FRI-100 heated at 52 degrees C for 20 min in 100 mmol/L potassium phosphate buffer was determined. Brain heart infusion agar with 1% pyruvate (BHIP agar) supported the highest recovery of injured cells and was used as the control medium. Of the three selective media, significantly higher recovery of heat-injured cells was observed on BP agar than MSEY agar, and the poorest recovery was observed on MS agar (p < 0.05). Low recovery of unheated cells was obtained for MS compared with other media (p < 0.05). A reduction in populations occurred gradually in reagent-grade water stored for 14 days at -20 degrees C. There was no significant difference between BHIP agar and MS agar in the number of freeze-injured cells recovered from 1 to 14 days.