Objective To characterize the meningococcal strains isolated from cases and close contacts with meningococcal disease associated with an outbreak in a jail in May 2010 by investigating the national distribution of hyp...Objective To characterize the meningococcal strains isolated from cases and close contacts with meningococcal disease associated with an outbreak in a jail in May 2010 by investigating the national distribution of hyperinvasive ST-4821 serogroup C clone associated with this outbreak. Methods The cases were described based on the clinical symptoms and laboratory results. Pharyngeal swabs were cultured for N. meningitidis from men in the jail. Meningococcal isolates were identified by serogrouping, pulsed-field gel electrophoresis （PFGE） and multilocus sequence typing （MLST）, respectively. Four hundred and sixteen serogroup C N. meningitidis strains were collected from 27 provinces between 2003 and 2010 for a nationwide survey and analyzed by PFGE and MLST. Results Three persons in a jail system were infected with invasive N. meningitidis serogroup C. All isolates tested had matching PFGE patterns and belonged to the multilocus sequence type （ST） 4821 clonal complex. All 47 N. meningitidis strains were identified from the pharyngeal swabs of 166 peoples in the jail, and 26 of them belonged to ST-4821 serogroup C clone, and 90.14% （375/416） serogroup C strains identified in the nationwide survey belonged to the ST-4821 complex. The ST-4821 serogroup C clone was spread nationwide, distributed in 24 provinces, especially in eastern provinces between 2003 and 2010. Conclusion Endemic transmission and carriage rate of ST-4821 serogroup C clone are high in this jail system. The ST-4821 serogroup C clone is spreading in China and nationwide distributed despite the existence of some effective vaccines.展开更多
A total of 241 Escherichia coli （E. coli） isolates from 349 avian samples （292 from cloacae, 29 from feed and water, 28 from dust and padding） were collected from Northeast, South, North, and Central China in rece...A total of 241 Escherichia coli （E. coli） isolates from 349 avian samples （292 from cloacae, 29 from feed and water, 28 from dust and padding） were collected from Northeast, South, North, and Central China in recent years. The percentage of isolation was 69.1%. There are 67 serogroups each with 1-2 isolates distributed in different regions, and some of these regions had the preponderant serogroups. Antimicrobial-resistance （AR） of E. coli was so severe that the majority were multi-AR. Fifty percent strains were resistant to 10-19 antimicrobial drugs. Overall, the isolates represented resistance to nalidixic acid （88.1%）, tetracycline （85.7%）, sulfamethoxazole （81.0%）, trimethoprim-sulfamethpxazole （77.1%）, ampicillin （76.2%）, amoxilline （74.3%）, streplomycin （66.2%）, fluoroquinolones （57.1-66.7%）, chloramphenicol （52.9%）, gentamicin （39.0%）, and kanamycin （36.2%）. The isolates were sensitive to cefalexin, amoxilline-clavulanic acid, amikacin, and florfenicol with an AR rate of 0-19,5% only, The results showed that the AR was more severe in chicken farms in which the antibiotics were used broadly and repeatedly. This study indicated the AR characterization of E, coli in different areas of China. It will be a foundation for studying AR mechanism and regulating the usage of antimicrobial in the poultry industry.展开更多
BACKGROUND Legionella pneumophila(L.pneumophila)is a gram-negative intracellular bacillus composed of sixteen different serogroups.It is mostly known to cause pneumonia in individuals with known risk factors as immuno...BACKGROUND Legionella pneumophila(L.pneumophila)is a gram-negative intracellular bacillus composed of sixteen different serogroups.It is mostly known to cause pneumonia in individuals with known risk factors as immunocompromised status,tobacco use,chronic organ failure or age older than 50 years.Although parapneumonic pleural effusion is frequent in legionellosis,pleural empyema is very uncommon.In this study,we report a case of fatal pleural empyema caused by L.pneumophila serogroup 1 in an 81-year-old man with multiple risk factors.CASE SUMMARY An 81-year-old man presented to the emergency with a 3 wk dyspnea,fever and left chest pain.His previous medical conditions were chronic lymphocytic leukemia,diabetes mellitus,chronic kidney failure,hypertension and hyperlipidemia,without tobacco use.Chest X-ray and comouted tomographyscan confirmed a large left pleural effusion,which puncture showed a citrine exudate with negative standard bacterial cultures.Despite intravenous cefotaxime antibiotherapy,patient’s worsening condition after 10 d led to thoracocentesis and evacuation of 2 liters of pus.The patient progressively developed severe hypoxemia and multiorgan failure occurred.The patient was treated by antibiotherapy with cefepime and amikacin and with adequate symptomatic shock treatment,but died of uncontrolled sepsis.The next day,cultures of the surgical pleural liquid samples yielded L.pneumophila serogroup 1,consistent with the diagnosis of pleural legionellosis.CONCLUSION L.pneumophila should be considered in patients with multiple risk factors and undiagnosed pleural empyema unresponsive to conventional antibiotherapy.展开更多
The African meningitis belt(AMB)faces recurring epidemics of Neisseria meningitidis(Nm)(a bacterium that causes meningococcal meningitis),posing significant public health challenges.This study develops a Susceptible-C...The African meningitis belt(AMB)faces recurring epidemics of Neisseria meningitidis(Nm)(a bacterium that causes meningococcal meningitis),posing significant public health challenges.This study develops a Susceptible-Carrier-Infected-Recovered(SCIR)-based dynamic model to investigate Nm transmission dynamics in the AMB region,focussing on the impact of pentavalent meningococcal conjugate vaccines targeting serogroups A,C,W-135,Y,and X.By incoporating vaccination strategies into the model,we provide a comprehensive framework for evaluating vaccine effectiveness and informing outbreak prevention and control efforts.Our model stratifies the population into high-risk individuals(ages 1–29 years),who are the primary targets of vaccination campaigns,and low-risk individuals(all other age groups),capturing differences in susceptibility and vaccine coverage.Our results reveal that the introduction of pentavalent vaccines significantly reduces the prevalence of carriers,particularly among high-risk groups,thereby curbing transmission and mitigating epidemic risks across the AMB region.Key epidemiological parameters,including reproduction numbers(R0),are derived to support targeted intervention strategies.Further analysis highlights the role of vaccination in lowering Nm transmissibility,especially in densely populated settings where close contact accelerates spread.Moreover,potential drivers of Nm outbreaks,including climate variability,socioeconomic disparities,and population density,are identified,highlighting the need for integrated public health intervention strategies.Further simulations also reveal the effectiveness of pentavalent vaccination among high-risk populations;however,further research is urgently needed to understand disease heterogeneity and vulnerability,particularly in young children and underserved communities.Thus,this study contribute to advancing our understanding of effective and sustainable vaccination strategies and enhancing epidemic preparedness in meningitis-endemic regions.展开更多
Neisseria meningitidis is the leading cause of bacterial meningitis and classified into 13serogroups based on the immunological reactivity of the capsular polysaccharide.1 Serogroups A, B, C, W135 and Y are the most c...Neisseria meningitidis is the leading cause of bacterial meningitis and classified into 13serogroups based on the immunological reactivity of the capsular polysaccharide.1 Serogroups A, B, C, W135 and Y are the most common causes of meningitis.2 Among them, serogroup A and C are the major causes of epidemics in Africa and Asia.2 Most of the epidemic outbreaks of meningococcal meningitis are caused by serogroup A Neisseria meningitidis strain from the 1950s to the 1980s in China.3 During the years 2003 and 2005, a new sequence type （ST-4821） of serogroup C was identified in the Anhui and 11 other provinces of China.4展开更多
Neisseria meningitidis （N. meningitidis） is classified into 13 serogroups based on the immunological reactivity of the capsular polysaccharide.Serogourp-s A,B and C are responsible for over 90% of meningococcal dise...Neisseria meningitidis （N. meningitidis） is classified into 13 serogroups based on the immunological reactivity of the capsular polysaccharide.Serogourp-s A,B and C are responsible for over 90% of meningococcal disease.2 In developed countries, endemic disease is generally caused by serogroups B and C.展开更多
This paper has been motivated by the following biological question: how influential me desert uerosols in the transmission of meningitidis serogroup A (MenA)? A mathematical model for the dynamical transmission of Men...This paper has been motivated by the following biological question: how influential me desert uerosols in the transmission of meningitidis serogroup A (MenA)? A mathematical model for the dynamical transmission of MenA is considered,with the aim of investigating the impact of desert aerosols.Sensitivity analysis of the model has been performed in order to determine the impact of related parameters on meningitis outbreak.We derive the basic reproduction number R0.We prove that there exists a threshold parameter ζ such that when R0 <ζ< 1,the disease-free equilibrium is globally asymptotically stable (GAS).However,when ζ< R0 < 1,the model exhibits the phenomenon of backward bifurcation.At the endemic level,we show that the number of infectious individuals in the presence of desert aerosols is larger than the correspond-ing number without the presence of desert aerosols.In conjunction with the inequality R0^0< R0 where R0^0 is the basic reproduction number without desert aerosols,we found that the ingestion of aerosols by carriers will increase the endemic level,and the severity of the outbreak.This suggests that the control of MenA passes through a combination of a large coverage vaccination of young susceptible individuals and the production of a vaccine with a high level of efficacy as well as respecting the hygienic rules to avoid the inhalation of desert aerosols.Theoretical results are supported by numerical simulations.展开更多
基金supported by Research Fund from Ministry of Health and Ministry of Science and Technology of the People’s Republic of China,2013ZX10004221,2012ZX10004215,and 2011CB504900
文摘Objective To characterize the meningococcal strains isolated from cases and close contacts with meningococcal disease associated with an outbreak in a jail in May 2010 by investigating the national distribution of hyperinvasive ST-4821 serogroup C clone associated with this outbreak. Methods The cases were described based on the clinical symptoms and laboratory results. Pharyngeal swabs were cultured for N. meningitidis from men in the jail. Meningococcal isolates were identified by serogrouping, pulsed-field gel electrophoresis （PFGE） and multilocus sequence typing （MLST）, respectively. Four hundred and sixteen serogroup C N. meningitidis strains were collected from 27 provinces between 2003 and 2010 for a nationwide survey and analyzed by PFGE and MLST. Results Three persons in a jail system were infected with invasive N. meningitidis serogroup C. All isolates tested had matching PFGE patterns and belonged to the multilocus sequence type （ST） 4821 clonal complex. All 47 N. meningitidis strains were identified from the pharyngeal swabs of 166 peoples in the jail, and 26 of them belonged to ST-4821 serogroup C clone, and 90.14% （375/416） serogroup C strains identified in the nationwide survey belonged to the ST-4821 complex. The ST-4821 serogroup C clone was spread nationwide, distributed in 24 provinces, especially in eastern provinces between 2003 and 2010. Conclusion Endemic transmission and carriage rate of ST-4821 serogroup C clone are high in this jail system. The ST-4821 serogroup C clone is spreading in China and nationwide distributed despite the existence of some effective vaccines.
文摘A total of 241 Escherichia coli （E. coli） isolates from 349 avian samples （292 from cloacae, 29 from feed and water, 28 from dust and padding） were collected from Northeast, South, North, and Central China in recent years. The percentage of isolation was 69.1%. There are 67 serogroups each with 1-2 isolates distributed in different regions, and some of these regions had the preponderant serogroups. Antimicrobial-resistance （AR） of E. coli was so severe that the majority were multi-AR. Fifty percent strains were resistant to 10-19 antimicrobial drugs. Overall, the isolates represented resistance to nalidixic acid （88.1%）, tetracycline （85.7%）, sulfamethoxazole （81.0%）, trimethoprim-sulfamethpxazole （77.1%）, ampicillin （76.2%）, amoxilline （74.3%）, streplomycin （66.2%）, fluoroquinolones （57.1-66.7%）, chloramphenicol （52.9%）, gentamicin （39.0%）, and kanamycin （36.2%）. The isolates were sensitive to cefalexin, amoxilline-clavulanic acid, amikacin, and florfenicol with an AR rate of 0-19,5% only, The results showed that the AR was more severe in chicken farms in which the antibiotics were used broadly and repeatedly. This study indicated the AR characterization of E, coli in different areas of China. It will be a foundation for studying AR mechanism and regulating the usage of antimicrobial in the poultry industry.
文摘BACKGROUND Legionella pneumophila(L.pneumophila)is a gram-negative intracellular bacillus composed of sixteen different serogroups.It is mostly known to cause pneumonia in individuals with known risk factors as immunocompromised status,tobacco use,chronic organ failure or age older than 50 years.Although parapneumonic pleural effusion is frequent in legionellosis,pleural empyema is very uncommon.In this study,we report a case of fatal pleural empyema caused by L.pneumophila serogroup 1 in an 81-year-old man with multiple risk factors.CASE SUMMARY An 81-year-old man presented to the emergency with a 3 wk dyspnea,fever and left chest pain.His previous medical conditions were chronic lymphocytic leukemia,diabetes mellitus,chronic kidney failure,hypertension and hyperlipidemia,without tobacco use.Chest X-ray and comouted tomographyscan confirmed a large left pleural effusion,which puncture showed a citrine exudate with negative standard bacterial cultures.Despite intravenous cefotaxime antibiotherapy,patient’s worsening condition after 10 d led to thoracocentesis and evacuation of 2 liters of pus.The patient progressively developed severe hypoxemia and multiorgan failure occurred.The patient was treated by antibiotherapy with cefepime and amikacin and with adequate symptomatic shock treatment,but died of uncontrolled sepsis.The next day,cultures of the surgical pleural liquid samples yielded L.pneumophila serogroup 1,consistent with the diagnosis of pleural legionellosis.CONCLUSION L.pneumophila should be considered in patients with multiple risk factors and undiagnosed pleural empyema unresponsive to conventional antibiotherapy.
文摘The African meningitis belt(AMB)faces recurring epidemics of Neisseria meningitidis(Nm)(a bacterium that causes meningococcal meningitis),posing significant public health challenges.This study develops a Susceptible-Carrier-Infected-Recovered(SCIR)-based dynamic model to investigate Nm transmission dynamics in the AMB region,focussing on the impact of pentavalent meningococcal conjugate vaccines targeting serogroups A,C,W-135,Y,and X.By incoporating vaccination strategies into the model,we provide a comprehensive framework for evaluating vaccine effectiveness and informing outbreak prevention and control efforts.Our model stratifies the population into high-risk individuals(ages 1–29 years),who are the primary targets of vaccination campaigns,and low-risk individuals(all other age groups),capturing differences in susceptibility and vaccine coverage.Our results reveal that the introduction of pentavalent vaccines significantly reduces the prevalence of carriers,particularly among high-risk groups,thereby curbing transmission and mitigating epidemic risks across the AMB region.Key epidemiological parameters,including reproduction numbers(R0),are derived to support targeted intervention strategies.Further analysis highlights the role of vaccination in lowering Nm transmissibility,especially in densely populated settings where close contact accelerates spread.Moreover,potential drivers of Nm outbreaks,including climate variability,socioeconomic disparities,and population density,are identified,highlighting the need for integrated public health intervention strategies.Further simulations also reveal the effectiveness of pentavalent vaccination among high-risk populations;however,further research is urgently needed to understand disease heterogeneity and vulnerability,particularly in young children and underserved communities.Thus,this study contribute to advancing our understanding of effective and sustainable vaccination strategies and enhancing epidemic preparedness in meningitis-endemic regions.
文摘Neisseria meningitidis is the leading cause of bacterial meningitis and classified into 13serogroups based on the immunological reactivity of the capsular polysaccharide.1 Serogroups A, B, C, W135 and Y are the most common causes of meningitis.2 Among them, serogroup A and C are the major causes of epidemics in Africa and Asia.2 Most of the epidemic outbreaks of meningococcal meningitis are caused by serogroup A Neisseria meningitidis strain from the 1950s to the 1980s in China.3 During the years 2003 and 2005, a new sequence type （ST-4821） of serogroup C was identified in the Anhui and 11 other provinces of China.4
文摘Neisseria meningitidis （N. meningitidis） is classified into 13 serogroups based on the immunological reactivity of the capsular polysaccharide.Serogourp-s A,B and C are responsible for over 90% of meningococcal disease.2 In developed countries, endemic disease is generally caused by serogroups B and C.
文摘This paper has been motivated by the following biological question: how influential me desert uerosols in the transmission of meningitidis serogroup A (MenA)? A mathematical model for the dynamical transmission of MenA is considered,with the aim of investigating the impact of desert aerosols.Sensitivity analysis of the model has been performed in order to determine the impact of related parameters on meningitis outbreak.We derive the basic reproduction number R0.We prove that there exists a threshold parameter ζ such that when R0 <ζ< 1,the disease-free equilibrium is globally asymptotically stable (GAS).However,when ζ< R0 < 1,the model exhibits the phenomenon of backward bifurcation.At the endemic level,we show that the number of infectious individuals in the presence of desert aerosols is larger than the correspond-ing number without the presence of desert aerosols.In conjunction with the inequality R0^0< R0 where R0^0 is the basic reproduction number without desert aerosols,we found that the ingestion of aerosols by carriers will increase the endemic level,and the severity of the outbreak.This suggests that the control of MenA passes through a combination of a large coverage vaccination of young susceptible individuals and the production of a vaccine with a high level of efficacy as well as respecting the hygienic rules to avoid the inhalation of desert aerosols.Theoretical results are supported by numerical simulations.
