Even after Kudoa septempunctata parasitic in Olive flounder was found as a cause of food poisoning, similar cases of unknown cause were still taking place. Juvenile Pacific bluefin tuna (JPBT, hereafter) is often presented in those cases and it is suspected that K. hexapunctata parasitic in JPBT would be pathogenic for humans. We attempted to detect K. hexapunctata from JPBT leftover and patients' feces in 4 cases in Niigata prefecture from 2011 to 2014. In addition, we also investigated excretion of K. hexapunctata into the feces after intake of JPBT on a trial basis. The 4 cases occurred during summer from July to September. K. hexapunctata was detected from JPBT leftover and patients' feces; therefore, it was estimated that K. hexapunctata could be parasitic in JPBT eaten in all those cases. Furthermore, we also found that JPBT and Olive flounder were eaten together in 2 cases, but K. septempunctata was not detected from patients' feces. The detection rate of K. hexapunctata from patients' feces was 86% for feces collected within 3 days after meal, but it was lowered 25% for feces collected after 1 week. The quantity of K. hexapunctata excreted into feces after intake of JPBT on a trial basis tended to be declining with time, and then K. hexapunctata was detected in feces up to approximately 3 days after intake of JPBT. From those results, a fecal examination would be important as collecting feces after meal or during an early stage, and feces collected within 3 days after meal could be appropriate for the examination. Cases in relation to JPBT are similar to those of food poisoning caused by K. septempunctata and it is suspected that K. hexapunctata might be the cause. For K. hexapunctata, it would be necessary to accumulate and examine the case data while clarifying its pathogenicity.
The fungicides such as the thiabendazole (TBZ) are commonly used to prevent postharvest-disease on citrus, but the resistant fungi have been reported to appear by the continuous administration of these fungicides. The aim of this study was to know the fungal contamination and the distribution of TBZ resistant Penicillium digitatum in two vegetable and fruit markets in Tokyo. As the results of fungal contamination research, Penicillium spp. was isolated from all of 30 air samples of markets, and dominant fungi were P. digitatum (12/30) of subgenus Penicillium. The Penicillium spp. isolated from all 16 samples of citrus and 3 samples of towels were mainly on P. digitatum. Twenty-two isolates of P. digitatum were examined for their sensitivity to TBZ by disk diffusion method, and 16 of 22 isolates were resistant to TBZ. In addition, these TBZ resistant strains had a point mutation in the β-tubulin gene corresponding to amino acid mutation (F→Y) on codon position 200. The distribution of TBZ resistant isolates was estimated 70.4% in 27 isolates of P. digitatum including 5 of dead strains by the mutation (F200Y) analysis.
Enrichment in modified EC broth (mEC) at 42ºC for detection of enterohemorrhagic Escherichia coli (EHEC) O26, O111 and O157 as an official method in Japan enhanced the growths of serogroups of O103, O121 and O145. In addition, various chromogenic agars were tested for the growth and morphology of various serogroups of EHEC. Multi or simple serogroups were distinguished in monocolor or various color depended in each serogroup. Furthermore, developed immunomagnetic beads targeting serogroups O103, O121 and O145 showed efficient performance to concentrate targeted bacteria in enrichment culture of food. In this study, it was suggested that enrichment in mEC, immunomagnetic separation method and culture on chromogenic agar were effective to isolate the 6 serogroups of EHEC.