Klebsiella pneumoniae(K.pneumoniae)is one of the main gram-negative bacilli in clini- cal practice.Nosocomial infections caused by K.pneumoniae producing extended-spectrumβ-lactama- ses(ESBLs)are very difficult to tr...Klebsiella pneumoniae(K.pneumoniae)is one of the main gram-negative bacilli in clini- cal practice.Nosocomial infections caused by K.pneumoniae producing extended-spectrumβ-lactama- ses(ESBLs)are very difficult to treat.This paper investigated the resistant characteristics of K.pneu- moniae producing ESBLs and their aminoglycoside-modifying enzyme gene expressions including N- acetyhransferases and O-adenyhransfemses.Bacteria identification and ESBLs confirmatory tests were performed by Phoenix^(TM)-100 system.And minimum inhibitory concentrations(MICs)of gentamicin, amikacin,kanamycin,tobramycin,netilmicin and neomycin in 53 K.pneumoniae isolates were de- tected by agar dilution.In addition,six aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction(PCR)and verified by DNA sequencer.It was found that imipenem and meropenem against 120 K.pneumoniae isolates produced powerful antimicrobial activities.The resis- tant rates of gentamicin and amikacin were 55.0% and 46.7%,respectively.Except neomycin, MIC_(50)and MIC_(90)of gentamicin,amikacin,kanamycin,tobramycin and netilmicin in 53 K.pneumoni- ae were all>128μg/ml,and the resistant rates were 83.0%,52.3%,75.5%,81.1% and 69.8%,respectively.However,neomycin was only 39.6%.In addition,five modifying enzyme genes,including aac(3)-Ⅰ,aac(3)-Ⅱ,aac(6')-Ⅰb,ant(3″)-Ⅰ,ant(2″)-Ⅰgenes,were found in 53 isoahes except aac(6')-Ⅱ,and their positive rates were 11.3%,67.9%,47.2%, 1.9% and 39.6%,respectively.It was also confirmed by nucleotide sequence analysis that the above resistant genes shared nearly 100% identities with GenBank published genes.The results obtained in the present study indicated that K.pneumoniae producing ESBLs strains are rapidly spreading in our hospital,and their resistance to aminoglycosides may be associated with aminoglycoside-modifying enz- yme gene expressions.展开更多
In this study, the prevalence of Extended Spectrum Beta-lactamase (ESBL) producing Klebsiella pneumoniae and Escherichia coli isolates from the University of Abuja Teaching Hospital and the National Hospital was deter...In this study, the prevalence of Extended Spectrum Beta-lactamase (ESBL) producing Klebsiella pneumoniae and Escherichia coli isolates from the University of Abuja Teaching Hospital and the National Hospital was determined. A total of two hundred and fifteen (215) clinical isolates were examined, of which 60% were E. coli and 40% K. pneumoniae respectively. The isolates were collected from various samples namely: Stool, Urine, Pus, High Vagina Swab, Sputum and Wound swab. Out of these isolates, 54 of K. pneumoniae were screened to be ESBL negative and 32 as ESBL positive isolates, while 88 and 40 E. coli were also screened as ESBL negative and ESBL positive isolates respectively. These represent 37.9% of all K. pneumoniae isolates and 31.25% of E. coli isolates respectively. The prevalence of ESBL among the species was not however statistically different (p > 0.05). Multiple resistance in these isolates was common and there is the need for routine screening of ESBL in our hospitals to guide rational and effective use of antibiotics.展开更多
Objective:To analyze the clinical distribution and drug resistance of Klebsiella pneumoniae isolated from patients in a certain hospital and provide a basis for the rational use of antibiotics in the clinical treatmen...Objective:To analyze the clinical distribution and drug resistance of Klebsiella pneumoniae isolated from patients in a certain hospital and provide a basis for the rational use of antibiotics in the clinical treatment for the infection of Klebsiella pneumoniae.Methods:1,192 strains of Klebsiella pneumoniae isolated from clinical specimens from 2012 to 2016 were collected.The strains were identified by VITEK-2 Compact Microbiological Identification System,and the corresponding results of the antimicrobial susceptibility test were interpreted in accordance with the standards recommended by Clinical and Laboratory Standards Institute(CLSI).Results:1,192 strains of Klebsiella pneumoniae were mainly isolated from sputum(65.6%),and most of them were from Respiratory Medicine Department and Medical Intensive Care Unit of Respiratory Medicine Department(MICU),accounting for 41.4%.Out of 1,192 strains,448 strains were detected to produce extended-spectrum beta-lactamases(ESBLs),accounting for 37.6%.In addition,the detection rates of ESBL-producing Klebsiella pneumoniae for 5 consecutive years showed an increasing trend year by year,and they were higher than the national average values published by China Antimicrobial Resistance Surveillance System(CARSS)in the corresponding period.The drug resistance rate of ESBL-producing Klebsiella pneumoniae was significantly higher than that of non ESBL-producing strains.Conclusions:The infection caused by Klebsiella pneumoniae mainly occurs in the lower respiratory tract,and the drug resistance rates of Klebsiella pneumoniae to antibiotics in the drug susceptibility spectrum are maintained at a high level.Therefore,the rational selection of antibiotics for the clinical treatment of lower respiratory tract infection caused by Klebsiella pneumoniae must be based on the production of ESBLs and the results of antimicrobial susceptibility test.展开更多
Background The extended-spectrum beta-lactamase （ESBL）-producing Klebsiella pneumoniae has increasingly become a major contributor to nosocomial infections and can exhibit multiple antibiotic resistance.Previous stu...Background The extended-spectrum beta-lactamase （ESBL）-producing Klebsiella pneumoniae has increasingly become a major contributor to nosocomial infections and can exhibit multiple antibiotic resistance.Previous studies have focused on the resistance genes in ESBL-producing strains,and the resistance-associated genetic environment of non-ESBL-producing strains has been ignored until now.Here,we investigated the occurrence and characteristics of non-ESBL-producing K.pneumoniae,which potentially carries unexpressed resistance genes.Methods K.pneumoniae strains were collected from five medical institutions in China from February 2010 to August 2013.The VITEK-2 ESBL detection system was used as a primary screen to identify the ESBL-producing phenotype,and the three primary types of ESBL-associated genes （CTX,SHV,and TEM） were detected by polymerase chain reaction （PCR） to confirm the strains presenting with a non-ESBL-producing phenotype.mRNA expression in the non-ESBL-producing strains was further screened by reverse-transcription PCR （RT-PCR） to validate their transcriptional efficiency.Results Out of 224 clinically isolated antibiotic-sensitive K.pneumoniae strains with a non-ESBL-producing phenotype,5 （2.2％） were identified to carry inactivated ESBL blaSHV genes with intact upstream promoter regions and resistance gene sequences.Interestingly,three of the five antibiotic-sensitive K.pneumoniae strains containing ESBL blaSHV genes still exhibited mRNA transcription of blasHv,while the other two exhibited no mRNA transcription.Conclusion These findings suggest that inactivated ESBL genes exist in non-ESBL-producing antibiotic-sensitive K.pneumoniae strains,which have the potential to transform the strain into an ESBL phenotype if an inappropriate application or overdose of antibiotics is implemented during clinical management.展开更多
文摘Klebsiella pneumoniae(K.pneumoniae)is one of the main gram-negative bacilli in clini- cal practice.Nosocomial infections caused by K.pneumoniae producing extended-spectrumβ-lactama- ses(ESBLs)are very difficult to treat.This paper investigated the resistant characteristics of K.pneu- moniae producing ESBLs and their aminoglycoside-modifying enzyme gene expressions including N- acetyhransferases and O-adenyhransfemses.Bacteria identification and ESBLs confirmatory tests were performed by Phoenix^(TM)-100 system.And minimum inhibitory concentrations(MICs)of gentamicin, amikacin,kanamycin,tobramycin,netilmicin and neomycin in 53 K.pneumoniae isolates were de- tected by agar dilution.In addition,six aminoglycoside-modifying enzyme genes were amplified by polymerase chain reaction(PCR)and verified by DNA sequencer.It was found that imipenem and meropenem against 120 K.pneumoniae isolates produced powerful antimicrobial activities.The resis- tant rates of gentamicin and amikacin were 55.0% and 46.7%,respectively.Except neomycin, MIC_(50)and MIC_(90)of gentamicin,amikacin,kanamycin,tobramycin and netilmicin in 53 K.pneumoni- ae were all>128μg/ml,and the resistant rates were 83.0%,52.3%,75.5%,81.1% and 69.8%,respectively.However,neomycin was only 39.6%.In addition,five modifying enzyme genes,including aac(3)-Ⅰ,aac(3)-Ⅱ,aac(6')-Ⅰb,ant(3″)-Ⅰ,ant(2″)-Ⅰgenes,were found in 53 isoahes except aac(6')-Ⅱ,and their positive rates were 11.3%,67.9%,47.2%, 1.9% and 39.6%,respectively.It was also confirmed by nucleotide sequence analysis that the above resistant genes shared nearly 100% identities with GenBank published genes.The results obtained in the present study indicated that K.pneumoniae producing ESBLs strains are rapidly spreading in our hospital,and their resistance to aminoglycosides may be associated with aminoglycoside-modifying enz- yme gene expressions.
文摘In this study, the prevalence of Extended Spectrum Beta-lactamase (ESBL) producing Klebsiella pneumoniae and Escherichia coli isolates from the University of Abuja Teaching Hospital and the National Hospital was determined. A total of two hundred and fifteen (215) clinical isolates were examined, of which 60% were E. coli and 40% K. pneumoniae respectively. The isolates were collected from various samples namely: Stool, Urine, Pus, High Vagina Swab, Sputum and Wound swab. Out of these isolates, 54 of K. pneumoniae were screened to be ESBL negative and 32 as ESBL positive isolates, while 88 and 40 E. coli were also screened as ESBL negative and ESBL positive isolates respectively. These represent 37.9% of all K. pneumoniae isolates and 31.25% of E. coli isolates respectively. The prevalence of ESBL among the species was not however statistically different (p > 0.05). Multiple resistance in these isolates was common and there is the need for routine screening of ESBL in our hospitals to guide rational and effective use of antibiotics.
文摘Objective:To analyze the clinical distribution and drug resistance of Klebsiella pneumoniae isolated from patients in a certain hospital and provide a basis for the rational use of antibiotics in the clinical treatment for the infection of Klebsiella pneumoniae.Methods:1,192 strains of Klebsiella pneumoniae isolated from clinical specimens from 2012 to 2016 were collected.The strains were identified by VITEK-2 Compact Microbiological Identification System,and the corresponding results of the antimicrobial susceptibility test were interpreted in accordance with the standards recommended by Clinical and Laboratory Standards Institute(CLSI).Results:1,192 strains of Klebsiella pneumoniae were mainly isolated from sputum(65.6%),and most of them were from Respiratory Medicine Department and Medical Intensive Care Unit of Respiratory Medicine Department(MICU),accounting for 41.4%.Out of 1,192 strains,448 strains were detected to produce extended-spectrum beta-lactamases(ESBLs),accounting for 37.6%.In addition,the detection rates of ESBL-producing Klebsiella pneumoniae for 5 consecutive years showed an increasing trend year by year,and they were higher than the national average values published by China Antimicrobial Resistance Surveillance System(CARSS)in the corresponding period.The drug resistance rate of ESBL-producing Klebsiella pneumoniae was significantly higher than that of non ESBL-producing strains.Conclusions:The infection caused by Klebsiella pneumoniae mainly occurs in the lower respiratory tract,and the drug resistance rates of Klebsiella pneumoniae to antibiotics in the drug susceptibility spectrum are maintained at a high level.Therefore,the rational selection of antibiotics for the clinical treatment of lower respiratory tract infection caused by Klebsiella pneumoniae must be based on the production of ESBLs and the results of antimicrobial susceptibility test.
文摘Background The extended-spectrum beta-lactamase （ESBL）-producing Klebsiella pneumoniae has increasingly become a major contributor to nosocomial infections and can exhibit multiple antibiotic resistance.Previous studies have focused on the resistance genes in ESBL-producing strains,and the resistance-associated genetic environment of non-ESBL-producing strains has been ignored until now.Here,we investigated the occurrence and characteristics of non-ESBL-producing K.pneumoniae,which potentially carries unexpressed resistance genes.Methods K.pneumoniae strains were collected from five medical institutions in China from February 2010 to August 2013.The VITEK-2 ESBL detection system was used as a primary screen to identify the ESBL-producing phenotype,and the three primary types of ESBL-associated genes （CTX,SHV,and TEM） were detected by polymerase chain reaction （PCR） to confirm the strains presenting with a non-ESBL-producing phenotype.mRNA expression in the non-ESBL-producing strains was further screened by reverse-transcription PCR （RT-PCR） to validate their transcriptional efficiency.Results Out of 224 clinically isolated antibiotic-sensitive K.pneumoniae strains with a non-ESBL-producing phenotype,5 （2.2％） were identified to carry inactivated ESBL blaSHV genes with intact upstream promoter regions and resistance gene sequences.Interestingly,three of the five antibiotic-sensitive K.pneumoniae strains containing ESBL blaSHV genes still exhibited mRNA transcription of blasHv,while the other two exhibited no mRNA transcription.Conclusion These findings suggest that inactivated ESBL genes exist in non-ESBL-producing antibiotic-sensitive K.pneumoniae strains,which have the potential to transform the strain into an ESBL phenotype if an inappropriate application or overdose of antibiotics is implemented during clinical management.
