Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selecte...Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.展开更多
BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneum...BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneumoniae infections(KPIs)in the bloodstream are common in LT recipients.We hypothesized that KPIs and carbapenemresistant Klebsiella pneumoniae(CRKP)infections may affect the outcomes of LT recipients.AIM To assess KPI incidence,timing,distribution,drug resistance,and risk factors following LT and its association with outcomes.METHODS This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University,a tertiary hospital,from January 2015 to January 2023.We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.RESULTS KPI incidence was 7.9%(n=32),with lung/thoracic cavity the most frequent site of infection;the median time from LT to KPI onset was 7.5 d.Of 44 Klebsiella pneumoniae isolates,43(97.7%)and 34(77.3%)were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline,respectively;>70%were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin.Female sex[odds ratio(OR)=2.827,95%confidence interval(CI):1.256-6.364;P=0.012],pre-LT diabetes(OR=2.794,95%CI:1.070-7.294;P=0.036),day 1 post-LT alanine aminotransferase(ALT)levels≥1500 U/L(OR=3.645,95%CI:1.671-7.950;P=0.001),and post-LT urethral catheter duration over 4 d(OR=2.266,95%CI:1.016-5.054;P=0.046)were risk factors for KPI.CRKP infections,but not KPIs,were risk factors for 6-month all-cause mortality post-LT.CONCLUSION KPIs occur frequently and rapidly after LT.Risk factors include female sex,pre-LT diabetes,increased post-LT ALT levels,and urethral catheter duration.CRKP infections,and not KPIs,affect mortality.展开更多
Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins ...Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins and other factors involved in various biological processes,includingβ-lactamase and antibiotic-resistance genes.This study aimed to reveal the transmission mechanism of OMV-mediated drug resistance of Klebsiella(K.)pneumoniae.Methods We selected CR-KP producing K.pneumoniae carbapenemase-2(KPC-2)to study whether they can transfer resistance genes through OMVs.The OMVs of CR-KP were obtained by ultracentrifugation,and incubated with carbapenem-sensitive K.pneumoniae for 4 h.Finally,the carbapenem-sensitive K.pneumoniae was tested for the presence of bla_(KPC-2)resistance gene and its sensitivity to carbapenem antibiotics.Results The existence of OMVs was observed by the electron microscopy.The extracted OMVs had bla_(KPC-2)resistance gene.After incubation with OMVs,bla_(KPC-2)resistance gene was detected in sensitive K.pneumoniae,and it became resistant to imipenem and meropenem.Conclusion This study demonstrated that OMVs isolated from KPC-2-producing CR-KP could deliver bla_(KPC-2)to sensitive K.pneumoniae,allowing the bacteria to produce carbapenemase,which may provide a novel target for innovative therapies in combination with conventional antibiotics for treating carbapenem-resistant Enterobacteriaceae.展开更多
Purpose: Recently, it was reported that Klebsiella pneumoniae is related to the onset of inflammatory bowel disease including the Crohn disease. It was frequently reported that K. pneumoniae was detected in human oral...Purpose: Recently, it was reported that Klebsiella pneumoniae is related to the onset of inflammatory bowel disease including the Crohn disease. It was frequently reported that K. pneumoniae was detected in human oral cavities. Regrettably, it currently remains unclear whether K. pneumoniae is part of the normal oral flora. The aim of this study was to establish the isolation and identification methods for K. pneumoniae from human oral cavities, and investigate its transmission pattern. Methods: A selective medium, OKPSM, for the isolation of K. pneumoniae from oral cavities was developed in this study. Also, PCR primer for the identification and detection at subspecies level of K. pneumoniae was designed. Results: OKPSM and PCR method using the primers designed in this study were useful for the isolation and identification of K. pneumoniae from human oral cavities. K. pneumoniae subsp. pneumoniae was detected at 10.0% in 30 saliva samples. On the other hand, K. pneumoniae subsp. ozaenae and K. pneumoniae subsp. rhinoscleromatis were detected from no sample. Moreover, K. pneumoniae subsp. pneumoniae isolates from same subject at 0 month and after 3 months showed same genotypes on AP-PCR using OPA-07 primer. Conclusion: These results indicated that human oral cavities were not suitable for the habitat of K. pneumoniae.展开更多
It is often said that the emergence of antimicrobial drug resistance(AMR)in pathogens is the major cause of mortality.In the present study,clinical microbiology data on infections caused by Klebsiella pneumoniae strai...It is often said that the emergence of antimicrobial drug resistance(AMR)in pathogens is the major cause of mortality.In the present study,clinical microbiology data on infections caused by Klebsiella pneumoniae strains and their antimicrobial drug resistance specifically to carbapenems retrieved from Clinical Epidemiology database of the Institute were analysed to determine the impact of carbapenem resistance in Klebsiellae isolated from the clinical samples of veterinary cases and outcome of the infection because in a few recent reports it is claimed that the presence of carbapenem-resistant Klebsiellae is associated with higher mortality in humans due to Klebsiella infections.The retrospective analysis of Klebsiella infections in animals and birds revealed that 21.8%of K.pneumoniae causing pneumonic or septicemic infections were carbapenem-resistant but the carbapenem resistance was not associated with increased numbers of deaths or recovery.It may be probably due to the fact that carbapenem drugs were not used for the treatment of infected animals and carbapenem resistance may not be associated with the lethality potential of Klebsiellae.展开更多
This paper focuses on the research of the bioconversion of 1,3-propanediol by Klebsiella pneumoniae. The linear correlation of cell growth and 1,3-propanediol synthesis was found. An equation of the relationship betwe...This paper focuses on the research of the bioconversion of 1,3-propanediol by Klebsiella pneumoniae. The linear correlation of cell growth and 1,3-propanediol synthesis was found. An equation of the relationship between cell growth and biocatalysis was given.With the analysis of metabolism, it was discovered that the cell regulated the NADH production by cell growth in order to supply enough reductive equivalent for enzyme catalysis. A conclusion was drawn that the cell growth was coupled with the reactivation of a key-enzyme which catalyzes 1,3-propanediol production in Klebsiella pneumoniae.展开更多
基金supported by the Ministry of Higher Education under the Fundamental Research Grant Scheme(FRGS/1/2021/SKK0/UPM/02/8)the Universiti Putra Malaysia Research University Grant Scheme(GP/IPS/2021/9702000).
文摘Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.
基金approved by the Ethics Committee of the Third Xiangya Hospital in accordance with the Declaration of Helsinki(No.24029).
文摘BACKGROUND Liver transplantation(LT)is the only curative treatment for end-stage liver disease.However,LT recipients are susceptible to infection,which is the leading cause of early mortality after LT.Klebsiella pneumoniae infections(KPIs)in the bloodstream are common in LT recipients.We hypothesized that KPIs and carbapenemresistant Klebsiella pneumoniae(CRKP)infections may affect the outcomes of LT recipients.AIM To assess KPI incidence,timing,distribution,drug resistance,and risk factors following LT and its association with outcomes.METHODS This retrospective study included 406 patients undergoing LT at The Third Xiangya Hospital of Central South University,a tertiary hospital,from January 2015 to January 2023.We investigated the risk factors for KPIs and assessed the impact of KPIs and CRKP infections on the prognosis of LT recipients using logistic regression analysis.RESULTS KPI incidence was 7.9%(n=32),with lung/thoracic cavity the most frequent site of infection;the median time from LT to KPI onset was 7.5 d.Of 44 Klebsiella pneumoniae isolates,43(97.7%)and 34(77.3%)were susceptible to polymyxin B or ceftazidime/avibactam and tigecycline,respectively;>70%were resistant to piperacillin/tazobactam,ceftazidime,cefepime,aztreonam,meropenem,and levofloxacin.Female sex[odds ratio(OR)=2.827,95%confidence interval(CI):1.256-6.364;P=0.012],pre-LT diabetes(OR=2.794,95%CI:1.070-7.294;P=0.036),day 1 post-LT alanine aminotransferase(ALT)levels≥1500 U/L(OR=3.645,95%CI:1.671-7.950;P=0.001),and post-LT urethral catheter duration over 4 d(OR=2.266,95%CI:1.016-5.054;P=0.046)were risk factors for KPI.CRKP infections,but not KPIs,were risk factors for 6-month all-cause mortality post-LT.CONCLUSION KPIs occur frequently and rapidly after LT.Risk factors include female sex,pre-LT diabetes,increased post-LT ALT levels,and urethral catheter duration.CRKP infections,and not KPIs,affect mortality.
基金supported by the National Natural Science Foundation of China(No.31771189)the Wuhan Health Commission(No.WX18C17 and No.WX19Q31)the Natural Science Foundation of Hubei Province,China(No.2017CFA065 and No.WJ2019H378).
文摘Objective The prevalence of carbapenem-resistant Klebsiella pneumoniae(CR-KP)is a global public health problem.It is mainly caused by the plasmid-carried carbapenemase gene.Outer membrane vesicles(OMVs)contain toxins and other factors involved in various biological processes,includingβ-lactamase and antibiotic-resistance genes.This study aimed to reveal the transmission mechanism of OMV-mediated drug resistance of Klebsiella(K.)pneumoniae.Methods We selected CR-KP producing K.pneumoniae carbapenemase-2(KPC-2)to study whether they can transfer resistance genes through OMVs.The OMVs of CR-KP were obtained by ultracentrifugation,and incubated with carbapenem-sensitive K.pneumoniae for 4 h.Finally,the carbapenem-sensitive K.pneumoniae was tested for the presence of bla_(KPC-2)resistance gene and its sensitivity to carbapenem antibiotics.Results The existence of OMVs was observed by the electron microscopy.The extracted OMVs had bla_(KPC-2)resistance gene.After incubation with OMVs,bla_(KPC-2)resistance gene was detected in sensitive K.pneumoniae,and it became resistant to imipenem and meropenem.Conclusion This study demonstrated that OMVs isolated from KPC-2-producing CR-KP could deliver bla_(KPC-2)to sensitive K.pneumoniae,allowing the bacteria to produce carbapenemase,which may provide a novel target for innovative therapies in combination with conventional antibiotics for treating carbapenem-resistant Enterobacteriaceae.
文摘Purpose: Recently, it was reported that Klebsiella pneumoniae is related to the onset of inflammatory bowel disease including the Crohn disease. It was frequently reported that K. pneumoniae was detected in human oral cavities. Regrettably, it currently remains unclear whether K. pneumoniae is part of the normal oral flora. The aim of this study was to establish the isolation and identification methods for K. pneumoniae from human oral cavities, and investigate its transmission pattern. Methods: A selective medium, OKPSM, for the isolation of K. pneumoniae from oral cavities was developed in this study. Also, PCR primer for the identification and detection at subspecies level of K. pneumoniae was designed. Results: OKPSM and PCR method using the primers designed in this study were useful for the isolation and identification of K. pneumoniae from human oral cavities. K. pneumoniae subsp. pneumoniae was detected at 10.0% in 30 saliva samples. On the other hand, K. pneumoniae subsp. ozaenae and K. pneumoniae subsp. rhinoscleromatis were detected from no sample. Moreover, K. pneumoniae subsp. pneumoniae isolates from same subject at 0 month and after 3 months showed same genotypes on AP-PCR using OPA-07 primer. Conclusion: These results indicated that human oral cavities were not suitable for the habitat of K. pneumoniae.
文摘It is often said that the emergence of antimicrobial drug resistance(AMR)in pathogens is the major cause of mortality.In the present study,clinical microbiology data on infections caused by Klebsiella pneumoniae strains and their antimicrobial drug resistance specifically to carbapenems retrieved from Clinical Epidemiology database of the Institute were analysed to determine the impact of carbapenem resistance in Klebsiellae isolated from the clinical samples of veterinary cases and outcome of the infection because in a few recent reports it is claimed that the presence of carbapenem-resistant Klebsiellae is associated with higher mortality in humans due to Klebsiella infections.The retrospective analysis of Klebsiella infections in animals and birds revealed that 21.8%of K.pneumoniae causing pneumonic or septicemic infections were carbapenem-resistant but the carbapenem resistance was not associated with increased numbers of deaths or recovery.It may be probably due to the fact that carbapenem drugs were not used for the treatment of infected animals and carbapenem resistance may not be associated with the lethality potential of Klebsiellae.
文摘This paper focuses on the research of the bioconversion of 1,3-propanediol by Klebsiella pneumoniae. The linear correlation of cell growth and 1,3-propanediol synthesis was found. An equation of the relationship between cell growth and biocatalysis was given.With the analysis of metabolism, it was discovered that the cell regulated the NADH production by cell growth in order to supply enough reductive equivalent for enzyme catalysis. A conclusion was drawn that the cell growth was coupled with the reactivation of a key-enzyme which catalyzes 1,3-propanediol production in Klebsiella pneumoniae.
