Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods P...Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods PFGE protocol was optimized in terms of plug preparation procedure, restriction enzymes and configuration of electrophoretic parameters. MLVA method was evaluated by finding variable number tandem repeats in two genomes of Citrobacter strains. The ribotyping was performed by using the automated RiboPrinter system. Results We optimized the plug preparation procedure, focused on the cell suspension concentration （turbidity of 2.5 to 3.5）, SDS addition （no SDS needed） and lysis time （1 h）, and selected the appropriate restriction enzyme （Xbal） and the electrophoretic parameters （1.0 s-20.0 s for 19 h） of PFGE. There was nearly no discriminatory power of MLVA between Citrobacter strains. For 51 Citrobacter strains, automated ribotyping gave a D-value of 0.9945, while PFGE gave a D-value of 0.9969. Both PFGE and automated ribotyping clustered strains from the same sources （with the same species from the same place at the same time identified as the same source） and divided strains from different sources （from different years, places and hosts） into different subtypes. Conclusion PFGE protocol established in this paper and automated ribotyping are suitable for application in Citrobacter subtyping.展开更多
This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using convention...This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using conventional methods,and then were isolated. The further tests and analysis of the isolated strain were developed,including the regression experiment to P. clarkia,the morphology,physiological and biochemical characteristics,sequence analysis of their 16 S rRNA and gyr B genes,and the susceptibility test to antibiotics. Large colonies with similar morphology and color were obtained. Strain X120523 was identified as Citrobacter freundii,proved to have strong pathogenicity,and was susceptible to quinolones and aminoglycosides.展开更多
Rationale:Infectious keratopathy is an ocular emergency with the potential to cause irreversible blindness.Patient's concerns:A 63-year-old diabetic man presented with a 3-day history of painful red right eye.He h...Rationale:Infectious keratopathy is an ocular emergency with the potential to cause irreversible blindness.Patient's concerns:A 63-year-old diabetic man presented with a 3-day history of painful red right eye.He had a history of multiple ocular surgeries in the affected eye without recent ocular trauma.Diagnosis:Infective crystalline keratopathy secondary to Citrobacter koseri.Interventions:Topical corticosteroids were discontinued,and dual topical antibiotic therapy of moxifloxacin 5%and gentamycin 0.3%were applied.Outcomes:Twelve hours after the start of treatment,the crystalline nature of the infiltrate disappeared,with enlargement of the epithelial defect.The antibiotic regime was continued and the lesion healed within a week of presentation with residual scarring.Lessons:Infective crystalline keratopathy classically presents with intrastromal branching fern-like opacities and minimal anterior segment inflammation in an immunosuppressed eye.The mainstay of management is corticosteroid discontinuation and the administration of empirical antibiotics until the results of the culture and sensitivity are available.In Citrobacter-related cases,treatment may result in a suppurative appearance before healing of the lesion.展开更多
Pathogenic strains of E. coli including enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enterotoxigenic E. coli (ETEC) are principle causes for diarrhoea in many parts of the globe. Citrobacter rode...Pathogenic strains of E. coli including enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enterotoxigenic E. coli (ETEC) are principle causes for diarrhoea in many parts of the globe. Citrobacter rodentium (C. rodentium), a gram negative bacterium, is a murine pathogen that also utilizes type III secretion system and similar virulence factors to EPEC and EHEC and forms comparable attaching/effacing lesions in the intestines as EPEC and EHEC. The infection caused by C. rodentium in mice is usually self-limiting and results in only minor systemic effects with higher mortality in some susceptible mouse strains. All these characteristics have made the bacteria a commonly used model to study host immune responses to pathogenic E. coli infection. In this review, we focus on the impact of virulence factors of the pathogen;different immune components involved in the immune response and summarize their role during C. rodentium infection.展开更多
Medicinal plants have been presented as a valuable source of preservation of human health. In special, Stryphnodendron barbatiman has been employed due to its antimicrobial activity. This plant is rich in tannins and ...Medicinal plants have been presented as a valuable source of preservation of human health. In special, Stryphnodendron barbatiman has been employed due to its antimicrobial activity. This plant is rich in tannins and has been used in popular medicine for the treatment of gastrointestinal disorder, treatment of lesions, and also as anti-inflammatory microbicide. Citrobacter freundii is a member of the family Enterobacteriaceae and is one of the major causes of opportunistic infections. This microorganism is a bacterium (bacillus) aerobic gram-negative with a length in the range of 1 to 5 mm. C. freundii is commonly found in water, soil, food and occasionally in the gastrointestinal tract of animals and humans. In this paper, we have demonstrated the antibacterial activity of S. barbatiman by observing cellular death by using inhibition halo approach. Atomic force microscopy and FT-IR spectroscopy results suggested that interaction between the main active components of S. barbatiman with cellular wall of C. freundii gives rise to cellular wall damage, and then leads this microorganism to death.展开更多
The genus Citrobacter commonly found in water and soil as well as the intestinal and urinary tracts of animals and humans.Although Citrobacter infections are infrequently diagnosed in environmental contexts,the rising...The genus Citrobacter commonly found in water and soil as well as the intestinal and urinary tracts of animals and humans.Although Citrobacter infections are infrequently diagnosed in environmental contexts,the rising incidence of nosocomial manifestations underscores the importance of considering this organism in the differential diagnosis of hospital-acquired infections.We present a case of patient with septic arthritis of the shoulder who had been originally admitted for the management of acute-on-chronic congestive heart failure exacerbation and severe sepsis.On hospital day 1,joint aspiration cultures and Gram stain confirmed the presence of Citrobacter koseri,a pathogen not commonly associated with septic arthritis,and ceftriaxone was administered to target it.On hospital day 7,antibiotic was transitioned to levofloxacin,every other day for 4 weeks.The patient was discharged to an acute rehabilitation facility after a 14-day hospital stay.This case stresses the importance of maintaining a broad differential diagnosis for any patients who present with fever and joint inflammation or swelling,especially in a postoperative setting.展开更多
To attain a better understanding of the effects of surfactants on the metabolic kinetics of hydrophobic organic compounds, the biodegradation of phenanthrene by Citrobacter sp. SA01 was investigated in a batch experim...To attain a better understanding of the effects of surfactants on the metabolic kinetics of hydrophobic organic compounds, the biodegradation of phenanthrene by Citrobacter sp. SA01 was investigated in a batch experiment containing Tween 80, sodium dodecyl benzene sulfonate and liquid mineral salt medium. The Monod model was modified to effectively describe the partition, phenanthrene biodegradation and biopolymer production. The results showed that Tween 80 and sodium dodecyl benzene sulfonate （each at 50 rag/L） enhanced phenanthrene metabolism and poly-β-hydroxybutyrate production as indicated by the increasing amounts of intermediates Coy 17.2% to 47.9%）, and percentages of poly-β- hydroxybutyrate （by 107.3% and 33.1%） within the cell dry weight when compared to their absence. The modified Monod model was capable of predicting microbial growth, phenanthrene depletion and biopolymer production. Furthermore, the Monod kinetic coefficients were largely determined by the surfactant-enhanced partition, suggesting that partitioning is a critical process in surfactant-enhanced bioremediation of hydro- phobic organic compounds.展开更多
Infectious diarrhea is a major cause of infant mortality in most developing countries. In this research, we evaluated the potential of immobilized Lactobacillus plantarum NCIMB 8826 on weanimix infant cereal and its e...Infectious diarrhea is a major cause of infant mortality in most developing countries. In this research, we evaluated the potential of immobilized Lactobacillus plantarum NCIMB 8826 on weanimix infant cereal and its effectiveness in reducing the severity of Citrobacter rodentium-induced diarrhea in weanling mice. Thirty-six C57BL/6 weanling mice were placed into four groups (n = 9 each;negative, positive, prevention and cure). Mice received either L. plantarum (109 CFU/g) immobilized on weanimix infant cereal 3 days before C. rodentium (109 CFU/ ml) infection (Prevention) or 3 days after C. rodentium infection (Cure). A positive control group was infected with C. rodentium only, while a nega-tive control group received neither L. plantarum nor C. rodentium. Positive control mice showed colonic mucosal and submucosal inflammation, erosion, and mucosal epithelia hyperplasia with the C. rodentium infection. Mice in the prevention and cure groups had less severe histologic alterations in the colon. Some beneficial effect of L. plantarum was observed in cecal short-chain fatty acid concentrations, which stimulates water and electrolytes absorption to reduce diarrhea. Our findings demonstrated that L. plantarum NCIMB 8826 could be immobilized on weanimix infant cereal to help reduce diarrhea during weaning.展开更多
The intestinal mucosal barrier serves as a vital guardian of the gut health,maintaining a delicate equilibrium between gut microbiota and host immune homeostasis.Gasdermin D(GSDMD),a key executioner of pyroptosis down...The intestinal mucosal barrier serves as a vital guardian of the gut health,maintaining a delicate equilibrium between gut microbiota and host immune homeostasis.Gasdermin D(GSDMD),a key executioner of pyroptosis downstream of the inflammasome,has been found to play intricate roles in modulating colitis by influencing intestinal macrophages and regulating mucus secretion from goblet cells.However,the exact nature of the regulatory function of GSDMD in maintaining intestinal immune homeostasis and defending against pathogens remains to be elucidated.In the current study,by using the Citrobacter rodentium infection model,we found that GSDMD played a key role in the defense against intestinal Citrobacter rodentium infection,with high expression levels in intestinal epithelial and lamina propria myeloid cells.Our results showed that GSDMD acted specifically in intestinal epithelial cells to combat the infection,independently of its effects on antimicrobial peptides or mucin secretion.Instead,the resistance was mediated by the N-terminal fragment of GSDMD,highlighting its importance in intestinal immunity.However,the specific mechanism underlying the N-terminal activity of GSDMD in protecting against intestinal bacterial infections requires future investigation.展开更多
从患典型鳃腺炎病中华鳖(Pelodiscus sinensis)肝脏和腹水处进行细菌接种,分离获得一株细菌。综合菌落形态,16 S rRNA序列进化分析和API细菌生化鉴定系统判定,所得菌株为弗氏柠檬酸杆菌(Citrobacter freundii)(SX43)。动物回归实验显示...从患典型鳃腺炎病中华鳖(Pelodiscus sinensis)肝脏和腹水处进行细菌接种,分离获得一株细菌。综合菌落形态,16 S rRNA序列进化分析和API细菌生化鉴定系统判定,所得菌株为弗氏柠檬酸杆菌(Citrobacter freundii)(SX43)。动物回归实验显示,分离株对小鼠的半数致死量(LD50)为106.5CFU,显示该菌株具有较强的致病性,可从实验幼鳖体内再次分离到相同的病原菌。常用药物的抗菌敏感性测定显示,菌株SX43对头孢哌酮、头孢曲松、头孢呋辛、复方新诺明、氯霉素高度敏感。展开更多
基金supported by the project (grant 2005CB522904 and 2005CB522905) from the Ministry of Scientific Technologythe project (grant 2008ZX10004-001, 2008ZX10004-008, and 2009ZX10004-101) from the Ministry of Scientific Technology and the Ministry of Health of the People’s Republic of China
文摘Objective To establish and compare the pulsed-field gel electrophoresis （PFGE）, multiple-locus variable number tandem repeat analysis （MLVA） and automated ribotyping for subtyping of Citrobacter strains. Methods PFGE protocol was optimized in terms of plug preparation procedure, restriction enzymes and configuration of electrophoretic parameters. MLVA method was evaluated by finding variable number tandem repeats in two genomes of Citrobacter strains. The ribotyping was performed by using the automated RiboPrinter system. Results We optimized the plug preparation procedure, focused on the cell suspension concentration （turbidity of 2.5 to 3.5）, SDS addition （no SDS needed） and lysis time （1 h）, and selected the appropriate restriction enzyme （Xbal） and the electrophoretic parameters （1.0 s-20.0 s for 19 h） of PFGE. There was nearly no discriminatory power of MLVA between Citrobacter strains. For 51 Citrobacter strains, automated ribotyping gave a D-value of 0.9945, while PFGE gave a D-value of 0.9969. Both PFGE and automated ribotyping clustered strains from the same sources （with the same species from the same place at the same time identified as the same source） and divided strains from different sources （from different years, places and hosts） into different subtypes. Conclusion PFGE protocol established in this paper and automated ribotyping are suitable for application in Citrobacter subtyping.
基金Supported by the Science and Technology Innovative Research Team of Anhui Academy of Agricultural Sciences(14C0504)the Youth Innovation Foundation of President of Anhui Academy of Agricultural Sciences(14B0529)Anhui Aquaculture Industry Technology System for Shrimp and Crab
文摘This experiment was conducted to clarify species and drug resistance of pathogen from the diseased Procambarus clarkia. Pathogenic bacteria from hepatopancreas of the diseased P. clarkia were examined using conventional methods,and then were isolated. The further tests and analysis of the isolated strain were developed,including the regression experiment to P. clarkia,the morphology,physiological and biochemical characteristics,sequence analysis of their 16 S rRNA and gyr B genes,and the susceptibility test to antibiotics. Large colonies with similar morphology and color were obtained. Strain X120523 was identified as Citrobacter freundii,proved to have strong pathogenicity,and was susceptible to quinolones and aminoglycosides.
文摘Rationale:Infectious keratopathy is an ocular emergency with the potential to cause irreversible blindness.Patient's concerns:A 63-year-old diabetic man presented with a 3-day history of painful red right eye.He had a history of multiple ocular surgeries in the affected eye without recent ocular trauma.Diagnosis:Infective crystalline keratopathy secondary to Citrobacter koseri.Interventions:Topical corticosteroids were discontinued,and dual topical antibiotic therapy of moxifloxacin 5%and gentamycin 0.3%were applied.Outcomes:Twelve hours after the start of treatment,the crystalline nature of the infiltrate disappeared,with enlargement of the epithelial defect.The antibiotic regime was continued and the lesion healed within a week of presentation with residual scarring.Lessons:Infective crystalline keratopathy classically presents with intrastromal branching fern-like opacities and minimal anterior segment inflammation in an immunosuppressed eye.The mainstay of management is corticosteroid discontinuation and the administration of empirical antibiotics until the results of the culture and sensitivity are available.In Citrobacter-related cases,treatment may result in a suppurative appearance before healing of the lesion.
文摘Pathogenic strains of E. coli including enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC), enterotoxigenic E. coli (ETEC) are principle causes for diarrhoea in many parts of the globe. Citrobacter rodentium (C. rodentium), a gram negative bacterium, is a murine pathogen that also utilizes type III secretion system and similar virulence factors to EPEC and EHEC and forms comparable attaching/effacing lesions in the intestines as EPEC and EHEC. The infection caused by C. rodentium in mice is usually self-limiting and results in only minor systemic effects with higher mortality in some susceptible mouse strains. All these characteristics have made the bacteria a commonly used model to study host immune responses to pathogenic E. coli infection. In this review, we focus on the impact of virulence factors of the pathogen;different immune components involved in the immune response and summarize their role during C. rodentium infection.
基金This work was supported by CNPq and Capes (Brazil).
文摘Medicinal plants have been presented as a valuable source of preservation of human health. In special, Stryphnodendron barbatiman has been employed due to its antimicrobial activity. This plant is rich in tannins and has been used in popular medicine for the treatment of gastrointestinal disorder, treatment of lesions, and also as anti-inflammatory microbicide. Citrobacter freundii is a member of the family Enterobacteriaceae and is one of the major causes of opportunistic infections. This microorganism is a bacterium (bacillus) aerobic gram-negative with a length in the range of 1 to 5 mm. C. freundii is commonly found in water, soil, food and occasionally in the gastrointestinal tract of animals and humans. In this paper, we have demonstrated the antibacterial activity of S. barbatiman by observing cellular death by using inhibition halo approach. Atomic force microscopy and FT-IR spectroscopy results suggested that interaction between the main active components of S. barbatiman with cellular wall of C. freundii gives rise to cellular wall damage, and then leads this microorganism to death.
文摘The genus Citrobacter commonly found in water and soil as well as the intestinal and urinary tracts of animals and humans.Although Citrobacter infections are infrequently diagnosed in environmental contexts,the rising incidence of nosocomial manifestations underscores the importance of considering this organism in the differential diagnosis of hospital-acquired infections.We present a case of patient with septic arthritis of the shoulder who had been originally admitted for the management of acute-on-chronic congestive heart failure exacerbation and severe sepsis.On hospital day 1,joint aspiration cultures and Gram stain confirmed the presence of Citrobacter koseri,a pathogen not commonly associated with septic arthritis,and ceftriaxone was administered to target it.On hospital day 7,antibiotic was transitioned to levofloxacin,every other day for 4 weeks.The patient was discharged to an acute rehabilitation facility after a 14-day hospital stay.This case stresses the importance of maintaining a broad differential diagnosis for any patients who present with fever and joint inflammation or swelling,especially in a postoperative setting.
基金supported by the National Key Basic Research Program of China (No. 2014CB441106)the National Natural Science Foundation of China (No. 21137003)
文摘To attain a better understanding of the effects of surfactants on the metabolic kinetics of hydrophobic organic compounds, the biodegradation of phenanthrene by Citrobacter sp. SA01 was investigated in a batch experiment containing Tween 80, sodium dodecyl benzene sulfonate and liquid mineral salt medium. The Monod model was modified to effectively describe the partition, phenanthrene biodegradation and biopolymer production. The results showed that Tween 80 and sodium dodecyl benzene sulfonate （each at 50 rag/L） enhanced phenanthrene metabolism and poly-β-hydroxybutyrate production as indicated by the increasing amounts of intermediates Coy 17.2% to 47.9%）, and percentages of poly-β- hydroxybutyrate （by 107.3% and 33.1%） within the cell dry weight when compared to their absence. The modified Monod model was capable of predicting microbial growth, phenanthrene depletion and biopolymer production. Furthermore, the Monod kinetic coefficients were largely determined by the surfactant-enhanced partition, suggesting that partitioning is a critical process in surfactant-enhanced bioremediation of hydro- phobic organic compounds.
基金supported by the Borlaug Leadership Enhancement in Agriculture Program(Borlaug LEAP)and the Borlaug Higher Education for Agriculture and Higher Education(BHEARD)under the CGIAR fund[grant number BFS-G-11-00002]the predecessor fund,the Food Security and Crisis Mitigation II[grant number EEM-G-00-04-00013].
文摘Infectious diarrhea is a major cause of infant mortality in most developing countries. In this research, we evaluated the potential of immobilized Lactobacillus plantarum NCIMB 8826 on weanimix infant cereal and its effectiveness in reducing the severity of Citrobacter rodentium-induced diarrhea in weanling mice. Thirty-six C57BL/6 weanling mice were placed into four groups (n = 9 each;negative, positive, prevention and cure). Mice received either L. plantarum (109 CFU/g) immobilized on weanimix infant cereal 3 days before C. rodentium (109 CFU/ ml) infection (Prevention) or 3 days after C. rodentium infection (Cure). A positive control group was infected with C. rodentium only, while a nega-tive control group received neither L. plantarum nor C. rodentium. Positive control mice showed colonic mucosal and submucosal inflammation, erosion, and mucosal epithelia hyperplasia with the C. rodentium infection. Mice in the prevention and cure groups had less severe histologic alterations in the colon. Some beneficial effect of L. plantarum was observed in cecal short-chain fatty acid concentrations, which stimulates water and electrolytes absorption to reduce diarrhea. Our findings demonstrated that L. plantarum NCIMB 8826 could be immobilized on weanimix infant cereal to help reduce diarrhea during weaning.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFA1303900 to S.Y.)the National Natural Science Foundation of China(Grant Nos.32270921 and 82070567 to S.Y.and 82204354 to Y.H.)+5 种基金the Open Project of the State Key Laboratory of Reproductive Medicine of Nanjing Medical University(Grant No.SKLRM-2021B3 to S.Y.)the Talent Cultivation Project of"Organized Scientific Research"of Nanjing Medical University(Grant No.NJMURC20220014 to S.Y.)the Natural Science Foundation of Jiangsu Province(Grant No.BK20221352 to B.W.)the Jiangsu Provincial Outstanding Postdoctoral Program(Grant No.2022ZB419 to Y.H.)the Postdoctoral Research Funding Project of Gusu School(Grant No.GSBSHKY202104 to Y.H.)the China Postdoctoral Science Foundation(Grant No.2023T160329 to Y.H.).
文摘The intestinal mucosal barrier serves as a vital guardian of the gut health,maintaining a delicate equilibrium between gut microbiota and host immune homeostasis.Gasdermin D(GSDMD),a key executioner of pyroptosis downstream of the inflammasome,has been found to play intricate roles in modulating colitis by influencing intestinal macrophages and regulating mucus secretion from goblet cells.However,the exact nature of the regulatory function of GSDMD in maintaining intestinal immune homeostasis and defending against pathogens remains to be elucidated.In the current study,by using the Citrobacter rodentium infection model,we found that GSDMD played a key role in the defense against intestinal Citrobacter rodentium infection,with high expression levels in intestinal epithelial and lamina propria myeloid cells.Our results showed that GSDMD acted specifically in intestinal epithelial cells to combat the infection,independently of its effects on antimicrobial peptides or mucin secretion.Instead,the resistance was mediated by the N-terminal fragment of GSDMD,highlighting its importance in intestinal immunity.However,the specific mechanism underlying the N-terminal activity of GSDMD in protecting against intestinal bacterial infections requires future investigation.
文摘从患典型鳃腺炎病中华鳖(Pelodiscus sinensis)肝脏和腹水处进行细菌接种,分离获得一株细菌。综合菌落形态,16 S rRNA序列进化分析和API细菌生化鉴定系统判定,所得菌株为弗氏柠檬酸杆菌(Citrobacter freundii)(SX43)。动物回归实验显示,分离株对小鼠的半数致死量(LD50)为106.5CFU,显示该菌株具有较强的致病性,可从实验幼鳖体内再次分离到相同的病原菌。常用药物的抗菌敏感性测定显示,菌株SX43对头孢哌酮、头孢曲松、头孢呋辛、复方新诺明、氯霉素高度敏感。
