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1.
Background
Klebsiella pneumoniae is an important gram-negative opportunistic pathogen causing primarily urinary tract infections, respiratory infections, and bacteraemia. The ability of bacteria to form biofilms on medical devices, e.g. catheters, has a major role in development of many nosocomial infections. Most clinical K. pneumoniae isolates express two types of fimbrial adhesins, type 1 fimbriae and type 3 fimbriae. In this study, we characterized the role of type 1 and type 3 fimbriae in K. pneumoniae biofilm formation. 相似文献2.
Nan Li Fei Wang Siqiang Niu Ju Cao Kaifeng Wu Youqiang Li Nanlin Yin Xuemei Zhang Weiliang Zhu Yibing Yin 《BMC microbiology》2009,9(1):129
Background
Due to the widespread abusage of antibiotics, antibiotic-resistance in Streptococcus pneumoniae (S. pneumoniae) has been increasing quickly in recent years, and it is obviously urgent to develop new types of antibiotics. Two-component systems (TCSs) are the major signal transduction pathways in bacteria and have emerged as potential targets for antibacterial drugs. Among the 13 pairs of TCSs proteins presenting in S. pneumoniae, VicR/K is the unique one essential for bacterium growth, and block agents to which, if can be found, may be developed as effective antibiotics against S. pneumoniae infection. 相似文献3.
R. Mohamudha Parveen Subha Manivannan B. N. Harish S. C. Parija 《Indian journal of microbiology》2012,52(1):35-40
Data on CTX-M type extended-spectrum β-lactamase (ESBL) produced by Gram-negative bacteria by molecular methods are limited
from India. This study was conducted to investigate the prevalence of CTX-M type ESBL producing Escherichia coli and Klebsiella pneumoniae from nosocomial isolates in a tertiary care hospital in southern India. A total of 179 clinical isolates of K. pneumoniae (n = 72) and E. coli (n = 107) were obtained in a period of 3 months and assessed for ESBL production phenotypically. Associated resistance to
a panel of antibiotics and Minimum Inhibitory Concentration for 3rd generation cephalosporins was determined. Phenotypically
ESBL positive isolates were subjected to PCR for bla
CTX-M gene using two sets of primers for the simultaneous detection of all the five major groups of CTX-M types. All the positive
isolates were then subjected to a group specific PCR to detect the prevalent group. Out of 179 isolates, 156 (87.1%) were
positive for ESBL phenotypically, which includes 39.2% of K. pneumoniae and 60.8% of E. coli. All of them were examined by PCR using two primers for the presence of bla
CTX-M genes. Among the 156 phenotypic positive isolates, 124 (79.4%) were positive for bla
CTX-M genes, of which 45 (36.2%) were K. pneumoniae, 79 (63.7%) were E. coli. When the 124 positive clinical isolates were further tested with CTX-M group-specific primers, all were positive for the
CTX-M-1 group. Our findings document evidence of the high prevalence of multidrug resistant CTX-M group 1 type ESBL among
nosocomial isolates in this region. High co-resistance to other non-β-lactam antibiotics is a major challenge for management
of ESBL infections. This is alarming and calls for the judicious use of carbapenems, especially in developing countries. This
has significant implications for patient management, and indicates the need for increased surveillance and for further molecular
characterization of these isolates. 相似文献
4.
Matthias Imöhl Ralf René Reinert Christina Mutscher Mark van der Linden 《BMC microbiology》2010,10(1):299
Background
Macrolide resistant Streptococcus pneumoniae has been on a gradual increase in Germany for over a decade. The current study was undertaken against the background of the recent observation of declining macrolide resistance rates especially among German children. Nationwide surveillance of invasive pneumococcal disease has been conducted in Germany since 1992. A population- and laboratory-based approach was used to collect data on invasive pneumococcal disease, and isolates sent to the National Reference Center for Streptococci by diagnostic microbiological laboratories from 1992 to 2008 were included in this study. 相似文献5.
Background
Mycoplasma pneumoniae has previously been characterized as a micro-organism that is genetically highly stable. In spite of this genetic stability, homologous DNA recombination has been hypothesized to lie at the basis of antigenic variation of the major surface protein, P1, of M. pneumoniae. In order to identify the proteins that may be involved in homologous DNA recombination in M. pneumoniae, we set out to characterize the MPN229 open reading frame (ORF), which bears sequence similarity to the gene encoding the single-stranded DNA-binding (SSB) protein of other micro-organisms. 相似文献6.
Background
Klebsiella variicola was very recently described as a new bacterial species and is very closely related to Klebsiella pneumoniae; in fact, K. variicola isolates were first identified as K. pneumoniae. Therefore, it might be the case that some isolates, which were initially classified as K. pneumoniae, are actually K. variicola. The aim of this study was to devise a multiplex-PCR probe that can differentiate isolates from these sister species.Result
This work describes the development of a multiplex-PCR method to identify K. variicola. This development was based on sequencing a K. variicola clinical isolate (801) and comparing it to other K. variicola and K. pneumoniae genomes. The phylogenetic analysis showed that K. variicola isolates form a monophyletic group that is well differentiated from K. pneumoniae. Notably, the isolate K. pneumoniae 342 and K. pneumoniae KP5-1 might have been misclassified because in our analysis, both clustered with K. variicola isolates rather than with K. pneumoniae. The multiplex-PCR (M-PCR-1 to 3) probe system could identify K. variicola with high accuracy using the shared unique genes of K. variicola and K. pneumoniae genomes, respectively. M-PCR-1 was used to assay a collection of multidrug-resistant (503) and antimicrobial-sensitive (557) K. pneumoniae clinical isolates. We found K. variicola with a prevalence of 2.1% (23/1,060), of them a 56.5% (13/23) of the isolates were multidrug resistant, and 43.5% (10/23) of the isolates were antimicrobial sensitive. The phylogenetic analysis of rpoB of K. variicola-positive isolates identified by multiplex-PCR support the correct identification and differentiation of K. variicola from K. pneumoniae clinical isolates.Conclusions
This multiplex-PCR provides the means to reliably identify and genotype K. variicola. This tool could be very helpful for clinical, epidemiological, and population genetics studies of this species. A low but significant prevalence of K. variicola isolates was found, implying that misclassification had occurred previously. We believe that our multiplex-PCR assay could be of paramount importance to understand the population dynamics of K. variicola in both clinical and environmental settings.7.
Hélène Nuyttens Camille Cyncynatus Hélène Renaudin Sabine Pereyre Cécile Bébéar 《BMC microbiology》2010,10(1):216
Background
Mycoplasma pneumoniae is responsible for acute respiratory tract infections (RTIs) common in children and young adults. As M. pneumoniae is innately resistant to β-lactams antibiotics usually given as the first-line treatment for RTIs, specific and early diagnosis is important in order to select the right treatment. Serology is the most used diagnostic method for M. pneumoniae infections. 相似文献8.
Meryem Berrazeg Seydina M. Diene Mourad Drissi Marie Kempf Hervé Richet Luce Landraud Jean-Marc Rolain 《PloS one》2013,8(4)
Background
Klebsiella pneumoniae is one of the most important pathogens responsible for nosocomial outbreaks worldwide. Epidemiological analyses are useful in determining the extent of an outbreak and in elucidating the sources and the spread of infections. The aim of this study was to investigate the epidemiological spread of K. pneumoniae strains using a MALDI-TOF MS approach.Methods
Five hundred and thirty-five strains of K. pneumoniae were collected between January 2008 and March 2011 from hospitals in France and Algeria and were identified using MALDI-TOF. Antibiotic resistance patterns were investigated. Clinical and epidemiological data were recorded in an Excel file, including clustering obtained from the MSP dendrogram, and were analyzed using PASW Statistics software.Results
Antibiotic susceptibility and phenotypic tests of the 535 isolates showed the presence of six resistance profiles distributed unequally between the two countries. The MSP dendrogram revealed five distinct clusters according to an arbitrary cut-off at the distance level of 500. Data mining analysis of the five clusters showed that K. pneumoniae strains isolated in Algerian hospitals were significantly associated with respiratory infections and the ESBL phenotype, whereas those from French hospitals were significantly associated with urinary tract infections and the wild-type phenotype.Conclusions
MALDI-TOF was found to be a promising tool to identify and differentiate between K. pneumoniae strains according to their phenotypic properties and their epidemiological distribution. This is the first time that MALDI-TOF has been used as a rapid tool for typing K. pneumoniae clinical isolates. 相似文献9.
Background
The serine/threonine kinase StkP of Streptococcus pneumoniae is a major virulence factor in the mouse model of infection. StkP is a modular protein with a N-terminal kinase domain a C-terminal PASTA domain carrying the signature of penicillin-binding protein (PBP) and prokaryotic serine threonine kinase. In laboratory cultures, one target of StkP is the phosphoglucosamine mutase GlmM involved in the first steps of peptidoglycan biosynthesis. In order to further elucidate the importance of StkP in S. pneumoniae, its role in resistance to β-lactams has been assessed by mutational analysis in laboratory cultures and its genetic conservation has been investigated in isolates from infected sites (virulent), asymptomatic carriers, susceptible and non-susceptible to β-lactams. 相似文献10.
Background
Amoebic liver abscess (ALA) and pyogenic liver abscesses (PLA) appear identical by ultrasound and other imaging techniques. Collection of blood or liver abscess pus for diagnosis of liver abscesses is an invasive procedure, and the procedure requires technical expertise and disposable syringes. Collection of urine is a noninvasive procedure. Therefore, there has been much interest shown towards the use of urine as an alternative clinical specimen for the diagnosis of some parasitic infections. Here, we report for the first time the detection of E. histolytica DNA excreted in the urine for diagnosis of the cases of ALA. 相似文献11.
Guma MK Abdeldaim Kristoffer Strålin Jens Korsgaard Jonas Blomberg Christina Welinder-Olsson Björn Herrmann 《BMC microbiology》2010,10(1):310
Background
Streptococcus pneumoniae and Haemophilus influenzae cause pneumonia and as Neisseria meningitidis they are important agents of meningitis. Although several PCR methods have been described for these bacteria the specificity is an underestimated problem. Here we present a quantitative multiplex real-time PCR (qmPCR) for detection of S. pneumoniae (9802 gene fragment), H. influenzae (omp P6 gene) and N. meningitidis (ctrA gene). The method was evaluated on bronchoalveolar lavage (BAL) samples from 156 adults with lower respiratory tract infection (LRTI) and 31 controls, and on 87 cerebrospinal fluid (CSF) samples from meningitis patients. 相似文献12.
Background
Klebsiella pneumoniae is a leading cause of hospital-acquired urinary tract infections and pneumonia worldwide, and is responsible for many cases of pyogenic liver abscess among diabetic patients in Asia. A defining characteristic of this pathogen is the presence of a thick, exterior capsule that has been reported to play a role in biofilm formation and to protect the organism from threats such antibiotics and host immune challenge.Findings
We constructed two knockout mutants of K. pneumoniae to investigate how perturbations to capsule biosynthesis alter the cellular phenotype. In the first mutant, we deleted the entire gene cluster responsible for biosynthesis of the extracellular polysaccharide capsule. In the second mutant, we deleted the capsule export subsystem within this cluster. We find that both knockout mutants have lower amounts of capsule but produce greater amounts of biofilm. Moreover, one of the two mutants abolishes fimbriae expression as well.Conclusions
These results are expected to provide insight into the interaction between capsule biosynthesis, biofilm formation, and fimbriae expression in this organism. 相似文献13.
14.
Geert?Claeys Thierry?De Baere Georges?Wauters Patricia?Vandecandelaere Gerda?Verschraegen An?Muylaert Mario?Vaneechoutte
Background
Enterobacter aerogenes and Klebsiella pneumoniae are common isolates in clinical microbiology and important as producers of extended spectrum β-lactamases (ESBL). The discrimination between both species, which is routinely based on biochemical characteristics, is generally accepted to be straightforward. Here we report that genotypically unrelated strains of E. aerogenes can be misidentified as K. pneumoniae by routine laboratories using standard biochemical identification and using identification automates. 相似文献15.
16.
Background
Streptococcus pneumoniae can be carried asymptomatically in the nasopharynx of its human host but can also cause a wide range of infections. A role for pneumococcal phase variants in the different lifestyles of this bacterium has been suggested but no systematic survey of the colony phenotypes of isolates associated with human infections has been undertaken. 相似文献17.
Veras DL Alves LC Brayner FA Guedes DR Maciel MA Rocha CR de Souza Lopes AC 《Current microbiology》2011,62(5):1610-1616
The aim of this study was to determine the prevalence of the bla
SHV gene in Klebsiella pneumoniae isolates from hospital and community infections and from the normal microbiota of healthy individuals in Recife, PE, Brazil.
Fifty-two K. pneumoniae isolates were analyzed regarding the presence of the bla
SHV gene, using PCR, and eight isolates were analyzed by DNA sequencing. This gene was detected in 16 isolates from hospital
infections, four from community infections, and nine from the normal microbiota. This was the first study to find the bla
SHV gene in K. pneumoniae isolates from the normal microbiota. Through DNA sequencing of eight K. pneumoniae isolates from hospital and community infections, with a resistance phenotype indicative of extended-spectrum β-lactamase
production, a new SHV variant named SHV-122 was found. We also detected the presence of bla
SHV-1, bla
SHV-11, bla
SHV-28, and bla
SHV-108. The results show that in Recife, Brazil, K. pneumoniae isolates that presented resistance to oxyimino-β-lactams had high prevalence and diversity of the bla
SHV gene. We also conclude that there was a high presence of the bla
SHV gene among isolates from the normal microbiota of healthy individuals. 相似文献
18.
Cheryl-lynn Y Ong Scott A Beatson Makrina Totsika Christiane Forestier Alastair G McEwan Mark A Schembri 《BMC microbiology》2010,10(1):183
Background
Catheter-associated urinary tract infection (CAUTI) is the most common nosocomial infection in the United States and is caused by a range of uropathogens. Biofilm formation by uropathogens that cause CAUTI is often mediated by cell surface structures such as fimbriae. In this study, we characterised the genes encoding type 3 fimbriae from CAUTI strains of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Citrobacter koseri and Citrobacter freundii. 相似文献19.
20.
Yi-Chyi Lai Ann-Chi Lin Ming-Ko Chiang Yu-Han Dai Chih-Chieh Hsu Min-Chi Lu Chun-Yi Liau Ying-Tsong Chen 《PloS one》2014,9(5)