Background Novel influenza A viruses of avian-origin may be the precursors of pandemic strains. This descriptive study aims to introduce a novel avian-origin influenza A （H10N8） virus which can infect humans and cau...Background Novel influenza A viruses of avian-origin may be the precursors of pandemic strains. This descriptive study aims to introduce a novel avian-origin influenza A （H10N8） virus which can infect humans and cause severe diseases. Methods Collecting clinical data of three cases of human infection with a novel reassortment avian influenza A （H10N8） virus in Nanchang, Jiangxi Province, China. Results Three cases of human infection with a new reassortment avian influenza A（H10N8） virus were described, of which two were fatal cases, and one was severe case. These cases presented with severe pneumonia that progressed to acute respiratory distress syndrome （ARDS） and intractable respiratory failure. Conclusion This novel reassortment avian influenza A （H10N8） virus in China resulted in fatal human infections, and should be added to concerns in clinical practice.展开更多
Background Extended-spectrum β-lactamase （ESBL）-producing Klebsiella pneumoniae （K.pneumoniae） is one of the most popular pathogens that cause refractory respiratory tract infection.The genetic environment,includ...Background Extended-spectrum β-lactamase （ESBL）-producing Klebsiella pneumoniae （K.pneumoniae） is one of the most popular pathogens that cause refractory respiratory tract infection.The genetic environment,including insertion sequences and the types of promoter,plays a key role in exploration of the mechanism of prevalence and dismission of the ESBL-producing K.pneumoniae isolates.The aim of the investigation was to target analysis the genetic environment and promoter sequences of blaCTX-M,blaSHV and blaTEM,the most popular β-lactamase genes harbored by ESBL-producing K.pneumoniae isolates.Methods From February 2010 to July 2011,158 of 416 K.pneumoniae isolates producing ESBL from patients with lower respiratory tract infection were collected from seven tertiary hospitals from Beijing,Anhui,Fujian,Liaoning,Hebei and Inner Mongolia Autonomous Region in China.The genetic environment including promoters of 10 types of blaCTX-M,18 types of blaSHVand 2 types of blaTEM were analyzed by amplification and direct sequencing with various sets of PCR primers.Results ISEcp1 was located upstream of the 5＇ end of the blaCTX-M gene in 130 （97.0％） out of 134 K.pneumoniae isolates harboring blaCTX-M and provided a conserved promoter to blaCTX-M.A non-coding sequence preceded by kdpC and recF was identified in all of the blaSHV genes except blaSHV-12 and blaSHV-2a.IS26 was also found upstream of 1 blaCTX-M-15,10 blaSHV-1 strains,4 blaTEM-1 and all of the blaSHV-2,blaSHV-2a,blaSHV-5 and blaSHV-12.Eighty-seven of 91 strains harboring blaTEM-1 carried a copy of Tn2 and IS26-blaTEM-1 fragments were also detected in 4 strains.With respect to K.pneumoniae,the genetic environment of blaCTX-M-38,blaSHV-142 and blaTEM-135 were firstly elaborated,and four kinds of novel genetic environment of blaCTX-M-3,blaCTX-M-15 and blaTEM-1 have been detected as well.Conclusions Perfective implementation of the genetic environment information of β-lactamase gene needs to be further explored and supplemented.ISEcp1 and IS26 elements are widespread upstream of the blaCTX-M,blaSHV and blaTEM genes and contribute to horizontal transmission and genetic expression.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
In the past ten years, we had experienced a series of .emerging severe acute respiratory infections （SARI）.Some of them became serious public health emergent events, such as severe acute respiratory syndrome （SARS...In the past ten years, we had experienced a series of .emerging severe acute respiratory infections （SARI）.Some of them became serious public health emergent events, such as severe acute respiratory syndrome （SARS） and novel A/H7N9 avian influenza. Tracing back to 2003, SARS originated from Guangdong province and spread to 29 countries and regions until it was completely controlled. Out of 8 096 probable SARS cases world-wide, 774 patients died; the mortality was 9.6%.1 There were 5 327 patients with SARS in China, and 1 002 （19%） of them were health care workers （HCW）. Nearly all the HCW got hospital acquired infection since there was no efficient preventive and protective system.展开更多
Staphylococcus aureus is a common human bacterium that sometimes becomes pathogenic,causing serious infections.A key feature of S.aureus is its ability to acquire resistance to antibiotics.The presence of the staphylo...Staphylococcus aureus is a common human bacterium that sometimes becomes pathogenic,causing serious infections.A key feature of S.aureus is its ability to acquire resistance to antibiotics.The presence of the staphylococcal cassette chromosome(SCC) element in serotypes of S.aureus has been confirmed using multiplex PCR assays.The SCC element is the only vector known to carry the mecA gene,which encodes methicillin resistance in S.aureus infections.Here,we report the genome sequence of a novel methicillin-sensitive S.aureus(MSSA) strain:SCC-like MSSA463.This strain was originally erroneously serotyped as methicillin-resistant S.aureus in a clinical laboratory using multiplex PCR methods.We sequenced the genome of SCC-like MSSA463 using pyrosequencing techniques and compared it with known genome sequences of other S.aureus isolates.An open reading frame(CZ049;AB037671) was identified downstream of attL and attR inverted repeat sequences.Our results suggest that a lateral gene transfer occurred between S.aureus and other organisms,partially changing S.aureus infectivity.We propose that attL and attR inverted repeats in S.aureus serve as frequent insertion sites for exogenous genes.展开更多
文摘Background Novel influenza A viruses of avian-origin may be the precursors of pandemic strains. This descriptive study aims to introduce a novel avian-origin influenza A （H10N8） virus which can infect humans and cause severe diseases. Methods Collecting clinical data of three cases of human infection with a novel reassortment avian influenza A （H10N8） virus in Nanchang, Jiangxi Province, China. Results Three cases of human infection with a new reassortment avian influenza A（H10N8） virus were described, of which two were fatal cases, and one was severe case. These cases presented with severe pneumonia that progressed to acute respiratory distress syndrome （ARDS） and intractable respiratory failure. Conclusion This novel reassortment avian influenza A （H10N8） virus in China resulted in fatal human infections, and should be added to concerns in clinical practice.
文摘Background Extended-spectrum β-lactamase （ESBL）-producing Klebsiella pneumoniae （K.pneumoniae） is one of the most popular pathogens that cause refractory respiratory tract infection.The genetic environment,including insertion sequences and the types of promoter,plays a key role in exploration of the mechanism of prevalence and dismission of the ESBL-producing K.pneumoniae isolates.The aim of the investigation was to target analysis the genetic environment and promoter sequences of blaCTX-M,blaSHV and blaTEM,the most popular β-lactamase genes harbored by ESBL-producing K.pneumoniae isolates.Methods From February 2010 to July 2011,158 of 416 K.pneumoniae isolates producing ESBL from patients with lower respiratory tract infection were collected from seven tertiary hospitals from Beijing,Anhui,Fujian,Liaoning,Hebei and Inner Mongolia Autonomous Region in China.The genetic environment including promoters of 10 types of blaCTX-M,18 types of blaSHVand 2 types of blaTEM were analyzed by amplification and direct sequencing with various sets of PCR primers.Results ISEcp1 was located upstream of the 5＇ end of the blaCTX-M gene in 130 （97.0％） out of 134 K.pneumoniae isolates harboring blaCTX-M and provided a conserved promoter to blaCTX-M.A non-coding sequence preceded by kdpC and recF was identified in all of the blaSHV genes except blaSHV-12 and blaSHV-2a.IS26 was also found upstream of 1 blaCTX-M-15,10 blaSHV-1 strains,4 blaTEM-1 and all of the blaSHV-2,blaSHV-2a,blaSHV-5 and blaSHV-12.Eighty-seven of 91 strains harboring blaTEM-1 carried a copy of Tn2 and IS26-blaTEM-1 fragments were also detected in 4 strains.With respect to K.pneumoniae,the genetic environment of blaCTX-M-38,blaSHV-142 and blaTEM-135 were firstly elaborated,and four kinds of novel genetic environment of blaCTX-M-3,blaCTX-M-15 and blaTEM-1 have been detected as well.Conclusions Perfective implementation of the genetic environment information of β-lactamase gene needs to be further explored and supplemented.ISEcp1 and IS26 elements are widespread upstream of the blaCTX-M,blaSHV and blaTEM genes and contribute to horizontal transmission and genetic expression.
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.
文摘In the past ten years, we had experienced a series of .emerging severe acute respiratory infections （SARI）.Some of them became serious public health emergent events, such as severe acute respiratory syndrome （SARS） and novel A/H7N9 avian influenza. Tracing back to 2003, SARS originated from Guangdong province and spread to 29 countries and regions until it was completely controlled. Out of 8 096 probable SARS cases world-wide, 774 patients died; the mortality was 9.6%.1 There were 5 327 patients with SARS in China, and 1 002 （19%） of them were health care workers （HCW）. Nearly all the HCW got hospital acquired infection since there was no efficient preventive and protective system.
基金supported by the National High Technology Research and Development Program (2006AA02Z4A9)the National Science and Technology Major Project of Ministry of Science and Technology of China (2009ZX10004,2012ZX10004206)the National Natural Science Foundation of China (30971610, 30900053)
文摘Staphylococcus aureus is a common human bacterium that sometimes becomes pathogenic,causing serious infections.A key feature of S.aureus is its ability to acquire resistance to antibiotics.The presence of the staphylococcal cassette chromosome(SCC) element in serotypes of S.aureus has been confirmed using multiplex PCR assays.The SCC element is the only vector known to carry the mecA gene,which encodes methicillin resistance in S.aureus infections.Here,we report the genome sequence of a novel methicillin-sensitive S.aureus(MSSA) strain:SCC-like MSSA463.This strain was originally erroneously serotyped as methicillin-resistant S.aureus in a clinical laboratory using multiplex PCR methods.We sequenced the genome of SCC-like MSSA463 using pyrosequencing techniques and compared it with known genome sequences of other S.aureus isolates.An open reading frame(CZ049;AB037671) was identified downstream of attL and attR inverted repeat sequences.Our results suggest that a lateral gene transfer occurred between S.aureus and other organisms,partially changing S.aureus infectivity.We propose that attL and attR inverted repeats in S.aureus serve as frequent insertion sites for exogenous genes.
