Flavotoxin A was isolated from Pseudomonas cocovenenans subsp. farinofermentans culture in semisolid potato-dextrose-agar medium, which was isolated from fermented corn meal that had caused food poisoning outbreaks in...Flavotoxin A was isolated from Pseudomonas cocovenenans subsp. farinofermentans culture in semisolid potato-dextrose-agar medium, which was isolated from fermented corn meal that had caused food poisoning outbreaks in China. The isolation, purification, and chemical structure of this toxin were studied. The NMR spectra, the uv spectra, and molar extinction coefficients, and the mass spectra of Flavotoxin A are in good agreement with those reported for bongkrekic acid. Therefore, Flavotoxin A and bongkrekic acid are the same organic chemical compound; the molecular formula is C_(28)H_(38)O_7. The oral LD_(50) of the purified Flavotoxin A in mice was 3.16mg/kg (1.53-6.15mg/kg). The existence of bongkrekic acid in toxic fermented corn samples collected during food poisoning outbreaks was also confirmed. It is concluded that bongkrekic acid has played an important role in the outbreaks of fermented corn poisoning. 1989 Academic Press, Inc.展开更多
Introduction:The hypervirulent communityassociated methicillin-resistant Staphylococcus aureus(S.aureus,CA-MRSA)sequence type 8(ST8)clone has disseminated globally yet remains only sporadically documented in Chinese c...Introduction:The hypervirulent communityassociated methicillin-resistant Staphylococcus aureus(S.aureus,CA-MRSA)sequence type 8(ST8)clone has disseminated globally yet remains only sporadically documented in Chinese clinical settings.To date,staphylococcal food poisoning outbreaks attributable to ST8 strains have not been reported in China.Methods:Comprehensive epidemiological and laboratory investigations were conducted,encompassing the isolation of pathogenic microorganisms from food samples,environmental swabs,and patient anal swabs.Recovered isolates underwent antimicrobial susceptibility testing,enterotoxin detection,whole-genome sequencing,and phylogenetic and prophage characterization.Results:Five S.aureus isolates were successfully recovered from seven specimens.All isolates were identified as ST8(CC8)-spa t024,harbored enterotoxin genes(sea,seq,and sek),and demonstrated penicillin resistance.Rice balls contaminated with the pathogen were identified as the outbreak source.Phylogenetic analysis revealed that the outbreak ST8 strains clustered within a distinct evolutionary subclade(Clade II.1)and exhibited close genetic relatedness to European lineages.The sea,seq,and sek genes were localized on a prophage carrying a type D immune evasion cluster that also encoded the sak and scn genes.Conclusions:This represents the first documented ST8-spa t024 methicillin-susceptible S.aureus food poisoning outbreak in China,involving a toxigenic clone with characteristics associated with hypervirulent lineages,thereby highlighting an emerging public health threat.Enhanced surveillance of ST8 strains among food products and food handlers is urgently needed.展开更多
文摘Flavotoxin A was isolated from Pseudomonas cocovenenans subsp. farinofermentans culture in semisolid potato-dextrose-agar medium, which was isolated from fermented corn meal that had caused food poisoning outbreaks in China. The isolation, purification, and chemical structure of this toxin were studied. The NMR spectra, the uv spectra, and molar extinction coefficients, and the mass spectra of Flavotoxin A are in good agreement with those reported for bongkrekic acid. Therefore, Flavotoxin A and bongkrekic acid are the same organic chemical compound; the molecular formula is C_(28)H_(38)O_7. The oral LD_(50) of the purified Flavotoxin A in mice was 3.16mg/kg (1.53-6.15mg/kg). The existence of bongkrekic acid in toxic fermented corn samples collected during food poisoning outbreaks was also confirmed. It is concluded that bongkrekic acid has played an important role in the outbreaks of fermented corn poisoning. 1989 Academic Press, Inc.
基金Supported by the Health Commission of Zhejiang Province Medical Science and Technology Program Project(No.2025HY1485)the Planned Science and Technology Project of Traditional Chinese Medicine of Zhejiang Province of China(No.2023ZL352)the Capital’s Funds for Health Improvement and Research(No.2024-2G-4363).
文摘Introduction:The hypervirulent communityassociated methicillin-resistant Staphylococcus aureus(S.aureus,CA-MRSA)sequence type 8(ST8)clone has disseminated globally yet remains only sporadically documented in Chinese clinical settings.To date,staphylococcal food poisoning outbreaks attributable to ST8 strains have not been reported in China.Methods:Comprehensive epidemiological and laboratory investigations were conducted,encompassing the isolation of pathogenic microorganisms from food samples,environmental swabs,and patient anal swabs.Recovered isolates underwent antimicrobial susceptibility testing,enterotoxin detection,whole-genome sequencing,and phylogenetic and prophage characterization.Results:Five S.aureus isolates were successfully recovered from seven specimens.All isolates were identified as ST8(CC8)-spa t024,harbored enterotoxin genes(sea,seq,and sek),and demonstrated penicillin resistance.Rice balls contaminated with the pathogen were identified as the outbreak source.Phylogenetic analysis revealed that the outbreak ST8 strains clustered within a distinct evolutionary subclade(Clade II.1)and exhibited close genetic relatedness to European lineages.The sea,seq,and sek genes were localized on a prophage carrying a type D immune evasion cluster that also encoded the sak and scn genes.Conclusions:This represents the first documented ST8-spa t024 methicillin-susceptible S.aureus food poisoning outbreak in China,involving a toxigenic clone with characteristics associated with hypervirulent lineages,thereby highlighting an emerging public health threat.Enhanced surveillance of ST8 strains among food products and food handlers is urgently needed.
