<i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> is an emerging ubiquitous and opportunistic pathogen that cur...<i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> is an emerging ubiquitous and opportunistic pathogen that currently contaminates a wide spectrum of foods including powdered milk and poses a lethal threat to neonates, the elderly and persons with immune deficiencies. They cause life threatening neonatal meningitis, septicemia, and necrotizing enterocolitis. A total of 360 samples of powdered infant formula were collected from postnatal hospital attendees reconstituting the PIF for their children in the North Central region of Nigeria where cases of infant mortality </span><span style="font-family:Verdana;">are </span><span style="font-family:""><span style="font-family:Verdana;">very high and presenting as enterocolitis and diarrhea. Pre-enriched samples were cultured in chromogenic </span><i><span style="font-family:Verdana;">Cronobacter</span></i><span style="font-family:Verdana;"> broth and were then further sub-cultured into a chromogenic </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> agar. They were positive, exhibiting yellowish cultures typical of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. Biochemical tests of the isolates were also carried out and indicated the presence of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The isolates were then characterized molecularly using specie specific PCR detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The targeted genes of interest were </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene and </span><i><span style="font-family:Verdana;">CPA</span></i><span style="font-family:Verdana;"> gene. The isolates tested showed bands for </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene on electrophoresis imager and were confirmed as </span><i><span style="font-family:Verdana;">Cronobacter sakazakii.</span></i><span style="font-family:Verdana;"> In Nigeria, majority of infants are still fed with PIF. There is no existing data on the detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> previously reported in the North central region of Nigeria hence the need to carry out the present study. The result of the study demonstrated the need for effective prevention and control measures as contamination of PIF with </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> constituted potential public health risk to neonates and infants.展开更多
Cronobacter spp.has strong resistance to desiccation and high permeability in Enterobacteriaceae,and powdered infant formula(PIF)is one of the main contamination routes.In recent years,the contamination of Cronobacter...Cronobacter spp.has strong resistance to desiccation and high permeability in Enterobacteriaceae,and powdered infant formula(PIF)is one of the main contamination routes.In recent years,the contamination of Cronobacter spp.in PIF incidents occurs from time to time,causing infant serious diseases or death.In this investigation,matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to identify the phenotypes of 35 Cronobacter strains isolated from PIF and its processing environment.Subsequently,the isolates were evaluated for drying and osmotic pressure tolerance.The results showed that the deactivation rate of the strains ranged from 9.01%to 77.57%,and the highest osmotic pressure condition the strains could tolerate was 6 g/100 mL Na Cl.In addition,there was a positive correlation between biofilm formation ability and desiccation resistance.Combined with transcriptomics,Cronobacter spp.could activate biofilm synthesis,produce more trehalose,accumulate betaine and electrolytes to stabilize intracellular structure under the two treatment conditions.A total of 31 and 43 genes were found related to desiccation and permeability resistance,respectively.And some genes(cysM,thuF,ycjO,etc.)were found to be associated with two tolerances for the first time.展开更多
Objectives:Cronobacter sakazakii,formerly Enterobacter sakazakii,is an emerging ubiquitous and opportunistic foodborne pathogen with a high mortality rate.It has been implicated in cases of meningitis,septicaemia,and ...Objectives:Cronobacter sakazakii,formerly Enterobacter sakazakii,is an emerging ubiquitous and opportunistic foodborne pathogen with a high mortality rate.It has been implicated in cases of meningitis,septicaemia,and necrotizing enterocolitis among infants worldwide in association with powdered infant formula(PIF).This study was an insilico designed peptide base kit framework,using immunoinformatic techniques for quick detection of C.sakazakii in PIF.Materials and Methods:In the present study,a peptide-based kit was designed with a bioinformatic technique to rapidly identify C.sakazakii in PIF using fhE,secY,and bcsC,which are genes responsible for its bioflm formation,as target genes.The antigenicity,membrane topology,and the presence of signal peptides of the target genes were analysed using VaxiJen,DeepTMHMM,and SignalP servers.To provide stability and fexibility to the multiple-epitope construct,the linear B cells and helper T cells(IL-4(interleukin 4)and IL-10(interleukin 10)inducing epitopes)were linked with a GSGSG linker followed by the addition of protein disulphide bonds.To ascertain specifcity,the multi-epitope construct was molecularly docked against genes from sources other than PIF,like alfalfa,and the environment,with PIF being the highest:–328.48.Finally,the codons were modifed using the pET28a(+)vector,and the resultant multi-epitope construct was successfully cloned in silico.Results:The fnal construct had a length of 486 bp,an instability index of 23.26,a theoretical pI of 9.34,a molecular weight of 16.5 kDa,and a Z-score of–3.41.Conclusions:The multi-epitope peptide construct could be a conceptual framework for creating a C.sakazakii peptide-based detection kit,which has the potential to provide fast and effcient detection.However,there is a need for additional validation through the in vitro and in vivo techniques.展开更多
Objective To investigate the occurrence and concentrations of melamine and its analogues in tainted infant formula and to identify the etiologic factors for the urinary stones epidemic in infants and young children in...Objective To investigate the occurrence and concentrations of melamine and its analogues in tainted infant formula and to identify the etiologic factors for the urinary stones epidemic in infants and young children in China in 2008. Methods Sanlu infant formula samples were collected from families of the affected children in Gansu province, and markets in Gansu and Hebei provinces and Beijing city. Melamine and its analogues, including cyanuric acid, ammeline, and ammelide were measured by gas chromatography/tandem mass spectrometry. Results High prevalence and concentrations of melamine were found in Sanlu infant formula samples, with low concentrations of cyanuric acid, ammeline and ammelide. Melamine were detected in 87 out of 111 Sanlu infant formula samples with a range of 118 to 4 700 mg/kg, Conclusion The results provide strong evidence for melamine as the etiological factor for the urinary stones epidemic in infants and young children in China in 2008.展开更多
A total of 151 infant formula powder samples were tested for the screening of the Enterobacteriaceae bacteria, and it had been contaminated by the conditioned pathogen like Enterobacter sakazakii, Klebsiella pneumonia...A total of 151 infant formula powder samples were tested for the screening of the Enterobacteriaceae bacteria, and it had been contaminated by the conditioned pathogen like Enterobacter sakazakii, Klebsiella pneumoniae, Klebsiella oxytoca, and Enterobacter cloacae. The results showed that six samples were separated Enterobacter sakazakii, 24 samples were separated Enterobacteriaceae by using the traditional validation and real-time fluorescence quantitative PCR. Then the result identified by API20E biochemistry test and VITEC2 identification system. Through the study we concluded the potential safety hazard of the current infant formula powder and should regard Enterobacteriaceae as an indicator to carry out effective management, the neglected mild and discontinuity contamination could be easily found, thus to guarantee the safety of the special group.展开更多
Laboratory-based pathogen isolation, identification, and toxicity determination were performed on samples from a suspected case of infant botulism. Mice injected with cultures generated from the enema sample and inges...Laboratory-based pathogen isolation, identification, and toxicity determination were performed on samples from a suspected case of infant botulism. Mice injected with cultures generated from the enema sample and ingested Powered infant formula （PIF） presented typical signs of botulism. Antitoxins to polyvalent botulinum neurotoxins （BoNTs） and monovalent BoNT type B antitoxin had protective effects. Clostridium botulinum isolated from the enema and residual PIF samples were positive for type B toxin. Pulsed-field gel electrophoresis （PFGE） revealed that the two strains of C. botulinum isolated from the two samples produced indistinguishable pulsotypes. These findings confirmed this case of type B infant botulism associated with the ingestion of PIF contaminated bv type B C. botulinum spores.展开更多
文摘<i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> is an emerging ubiquitous and opportunistic pathogen that currently contaminates a wide spectrum of foods including powdered milk and poses a lethal threat to neonates, the elderly and persons with immune deficiencies. They cause life threatening neonatal meningitis, septicemia, and necrotizing enterocolitis. A total of 360 samples of powdered infant formula were collected from postnatal hospital attendees reconstituting the PIF for their children in the North Central region of Nigeria where cases of infant mortality </span><span style="font-family:Verdana;">are </span><span style="font-family:""><span style="font-family:Verdana;">very high and presenting as enterocolitis and diarrhea. Pre-enriched samples were cultured in chromogenic </span><i><span style="font-family:Verdana;">Cronobacter</span></i><span style="font-family:Verdana;"> broth and were then further sub-cultured into a chromogenic </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> agar. They were positive, exhibiting yellowish cultures typical of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. Biochemical tests of the isolates were also carried out and indicated the presence of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The isolates were then characterized molecularly using specie specific PCR detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;">. The targeted genes of interest were </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene and </span><i><span style="font-family:Verdana;">CPA</span></i><span style="font-family:Verdana;"> gene. The isolates tested showed bands for </span><i><span style="font-family:Verdana;">ompA</span></i><span style="font-family:Verdana;"> gene on electrophoresis imager and were confirmed as </span><i><span style="font-family:Verdana;">Cronobacter sakazakii.</span></i><span style="font-family:Verdana;"> In Nigeria, majority of infants are still fed with PIF. There is no existing data on the detection of </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> previously reported in the North central region of Nigeria hence the need to carry out the present study. The result of the study demonstrated the need for effective prevention and control measures as contamination of PIF with </span><i><span style="font-family:Verdana;">Cronobacter sakazakii</span></i><span style="font-family:Verdana;"> constituted potential public health risk to neonates and infants.
基金supported by the Joint Funds of the National Natural Science Foundation of China(U21A20272)。
文摘Cronobacter spp.has strong resistance to desiccation and high permeability in Enterobacteriaceae,and powdered infant formula(PIF)is one of the main contamination routes.In recent years,the contamination of Cronobacter spp.in PIF incidents occurs from time to time,causing infant serious diseases or death.In this investigation,matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to identify the phenotypes of 35 Cronobacter strains isolated from PIF and its processing environment.Subsequently,the isolates were evaluated for drying and osmotic pressure tolerance.The results showed that the deactivation rate of the strains ranged from 9.01%to 77.57%,and the highest osmotic pressure condition the strains could tolerate was 6 g/100 mL Na Cl.In addition,there was a positive correlation between biofilm formation ability and desiccation resistance.Combined with transcriptomics,Cronobacter spp.could activate biofilm synthesis,produce more trehalose,accumulate betaine and electrolytes to stabilize intracellular structure under the two treatment conditions.A total of 31 and 43 genes were found related to desiccation and permeability resistance,respectively.And some genes(cysM,thuF,ycjO,etc.)were found to be associated with two tolerances for the first time.
文摘Objectives:Cronobacter sakazakii,formerly Enterobacter sakazakii,is an emerging ubiquitous and opportunistic foodborne pathogen with a high mortality rate.It has been implicated in cases of meningitis,septicaemia,and necrotizing enterocolitis among infants worldwide in association with powdered infant formula(PIF).This study was an insilico designed peptide base kit framework,using immunoinformatic techniques for quick detection of C.sakazakii in PIF.Materials and Methods:In the present study,a peptide-based kit was designed with a bioinformatic technique to rapidly identify C.sakazakii in PIF using fhE,secY,and bcsC,which are genes responsible for its bioflm formation,as target genes.The antigenicity,membrane topology,and the presence of signal peptides of the target genes were analysed using VaxiJen,DeepTMHMM,and SignalP servers.To provide stability and fexibility to the multiple-epitope construct,the linear B cells and helper T cells(IL-4(interleukin 4)and IL-10(interleukin 10)inducing epitopes)were linked with a GSGSG linker followed by the addition of protein disulphide bonds.To ascertain specifcity,the multi-epitope construct was molecularly docked against genes from sources other than PIF,like alfalfa,and the environment,with PIF being the highest:–328.48.Finally,the codons were modifed using the pET28a(+)vector,and the resultant multi-epitope construct was successfully cloned in silico.Results:The fnal construct had a length of 486 bp,an instability index of 23.26,a theoretical pI of 9.34,a molecular weight of 16.5 kDa,and a Z-score of–3.41.Conclusions:The multi-epitope peptide construct could be a conceptual framework for creating a C.sakazakii peptide-based detection kit,which has the potential to provide fast and effcient detection.However,there is a need for additional validation through the in vitro and in vivo techniques.
文摘Objective To investigate the occurrence and concentrations of melamine and its analogues in tainted infant formula and to identify the etiologic factors for the urinary stones epidemic in infants and young children in China in 2008. Methods Sanlu infant formula samples were collected from families of the affected children in Gansu province, and markets in Gansu and Hebei provinces and Beijing city. Melamine and its analogues, including cyanuric acid, ammeline, and ammelide were measured by gas chromatography/tandem mass spectrometry. Results High prevalence and concentrations of melamine were found in Sanlu infant formula samples, with low concentrations of cyanuric acid, ammeline and ammelide. Melamine were detected in 87 out of 111 Sanlu infant formula samples with a range of 118 to 4 700 mg/kg, Conclusion The results provide strong evidence for melamine as the etiological factor for the urinary stones epidemic in infants and young children in China in 2008.
文摘A total of 151 infant formula powder samples were tested for the screening of the Enterobacteriaceae bacteria, and it had been contaminated by the conditioned pathogen like Enterobacter sakazakii, Klebsiella pneumoniae, Klebsiella oxytoca, and Enterobacter cloacae. The results showed that six samples were separated Enterobacter sakazakii, 24 samples were separated Enterobacteriaceae by using the traditional validation and real-time fluorescence quantitative PCR. Then the result identified by API20E biochemistry test and VITEC2 identification system. Through the study we concluded the potential safety hazard of the current infant formula powder and should regard Enterobacteriaceae as an indicator to carry out effective management, the neglected mild and discontinuity contamination could be easily found, thus to guarantee the safety of the special group.
基金financially supported by the National Natural Science Foundation of China for Youth Fund Project:Integrated Identification and Risk Assessment of Clostridium and its Metabolites(81402684)
文摘Laboratory-based pathogen isolation, identification, and toxicity determination were performed on samples from a suspected case of infant botulism. Mice injected with cultures generated from the enema sample and ingested Powered infant formula （PIF） presented typical signs of botulism. Antitoxins to polyvalent botulinum neurotoxins （BoNTs） and monovalent BoNT type B antitoxin had protective effects. Clostridium botulinum isolated from the enema and residual PIF samples were positive for type B toxin. Pulsed-field gel electrophoresis （PFGE） revealed that the two strains of C. botulinum isolated from the two samples produced indistinguishable pulsotypes. These findings confirmed this case of type B infant botulism associated with the ingestion of PIF contaminated bv type B C. botulinum spores.
