Isolation and characterization of nitrogenase from Klebsiella pneumoniae

1986 ◽  
pp. 511-519 ◽  
Author(s):  
Vinod K. Shah
Keyword(s):  
Klebsiella Pneumoniae ◽  
Isolation And Characterization

scholarly journals Isolation and Characterization of Two Klebsiella pneumoniae Phages Encoding Divergent Depolymerases

2020 ◽  
Vol 21 (9) ◽  
pp. 3160 ◽  
Author(s):  
Pilar Domingo-Calap ◽  
Beatriz Beamud ◽  
Lucas Mora-Quilis ◽  
Fernando González-Candelas ◽  
Rafael Sanjuán
Keyword(s):  
Klebsiella Pneumoniae ◽  
Multidrug Resistant ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Isolation And Characterization ◽  
The Family ◽  
Important Challenge ◽  
Tail Spike ◽  
Reference Strains

The emergence of multidrug-resistant bacteria is a major global health concern. The search for new therapies has brought bacteriophages into the spotlight, and new phages are being described as possible therapeutic agents. Among the bacteria that are most extensively resistant to current antibiotics is Klebsiella pneumoniae, whose hypervariable extracellular capsule makes treatment particularly difficult. Here, we describe two new K. pneumoniae phages, πVLC5 and πVLC6, isolated from environmental samples. These phages belong to the genus Drulisvirus within the family Podoviridae. Both phages encode a similar tail spike protein with putative depolymerase activity, which is shared among other related phages and probably determines their ability to specifically infect K. pneumoniae capsular types K22 and K37. In addition, we found that phage πVLC6 also infects capsular type K13 and is capable of striping the capsules of K. pneumoniae KL2 and KL3, although the phage was not infectious in these two strains. Genome sequence analysis suggested that the extended tropism of phage πVLC6 is conferred by a second, divergent depolymerase. Phage πVLC5 encodes yet another putative depolymerase, but we found no activity of this phage against capsular types other than K22 and K37, after testing a panel of 77 reference strains. Overall, our results confirm that most phages productively infected one or few Klebsiella capsular types. This constitutes an important challenge for clinical applications.

scholarly journals Isolation and characterization of a sequence type 25 carbapenem-resistant hypervirulent Klebsiella pneumoniae from the mid-south region of China

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Jun Li ◽  
Zi-Yan Huang ◽  
Ting Yu ◽  
Xiao-Yan Tao ◽  
Yong-Mei Hu ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Capsular Polysaccharide ◽  
Control Strategies ◽  
Virulence Gene ◽  
Sequence Type ◽  
Pfge Typing ◽  
Main Cluster ◽  
Carbapenem Resistant ◽  
Isolation And Characterization

Abstract Background The molecular characterization of carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) isolates is not well studied. Our goal was to investigate the molecular epidemiology of CR-hvKP strains that were isolated from a Chinese hospital. Results All clinical carbapenem-resistant K. pneumoniae (CR-KP) isolates were collected and identified from patient samples between 2014 and 2017 from a Chinese hospital. The samples were subjected to screening for CR-hvKP by string test and the detection of the aerobactin gene. CR-hvKP isolates were further confirmed through neutrophil phagocytosis and a mice lethality assay. The CR-hvKP isolates were investigated for their capsular genotyping, virulence gene profiles, and the expression of carbapenemase genes by PCR and DNA sequencing. Multilocus sequence type (MLST) and pulsed-field gel electrophoresis (PFGE) were performed to exclude the homology of these isolates. Twenty strains were identified as CR-hvKP. These strains were resistant to imipenem and several other antibiotics, however, most were susceptible to amikacin. Notably, two isolates were not susceptible to tigecycline. Capsular polysaccharide synthesis genotyping revealed that 17 of the 20 CR-hvKP strains belonged to the K2 serotype, while the others belonged to serotypes other than K1, K2, K5, K20, and K57. The strains were found to be positive for 10 types of virulence genes and a variety of these genes coexisted in the same strain. Two carbapenemase genes were identified: blaKPC-2 (13/20) and blaNDM-1 (1/20). PFGE typing revealed eight clusters comprising isolates that belonged to MLST types ST25, ST11 and ST375, respectively. PFGE cluster A was identified as the main cluster, which included 11 isolates that belong to ST25 and mainly from ICU department. Conclusions Our findings suggest that hospital-acquired infections may contribute in part to the CR-hvKP strains identified in this study. It also suggests that ST25 CR-hvKP strain has a clonal distribution in our hospital. Therefore, effective surveillance and strict infection control strategies should be implemented to prevent outbreak by CR-hvKP strains in hospitals setting.

scholarly journals Isolation and characterization of a lytic bacteriophage φKp-lyy15 of Klebsiella pneumoniae

2015 ◽  
Vol 30 (1) ◽  
pp. 66-68 ◽  
Author(s):  
Yinyin Lu ◽  
Hongyan Shi ◽  
Zhe Zhang ◽  
Fang Han ◽  
Jinghua Li ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Lytic Bacteriophage ◽  
Isolation And Characterization

scholarly journals Isolation and Characterization of a Novel Lytic Bacteriophage against the K2 Capsule-Expressing Hypervirulent Klebsiella pneumoniae Strain 52145, and Identification of Its Functional Depolymerase

2021 ◽  
Vol 9 (3) ◽  
pp. 650
Author(s):  
Botond Zsombor Pertics ◽  
Alysia Cox ◽  
Adrienn Nyúl ◽  
Nóra Szamek ◽  
Tamás Kovács ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Antimicrobial Agents ◽  
Lytic Bacteriophage ◽  
Bacterial Cells ◽  
Narrow Host Range ◽  
Isolation And Characterization ◽  
Different Temperatures ◽  
Colonization Model

Klebsiella pneumoniae is among the leading bacteria that cause nosocomial infections. The capsule of this Gram-negative bacterium is a dominant virulence factor, with a prominent role in defense and biofilm formation. Bacteriophages, which are specific for one bacterial strain and its capsule type, can evoke the lysis of bacterial cells, aided by polysaccharide depolymerase enzymes. In this study, we isolated and characterized a bacteriophage against the nosocomial K. pneumoniae 52145 strain with K2 capsular serotype. The phage showed a narrow host range and stable lytic activity, even when exposed to different temperatures or detergents. Preventive effect of the phage in a nasal colonization model was investigated in vivo. Phlyogenetic analysis showed that the newly isolated Klebsiella phage B1 belongs to the Webervirus genus in Drexlerviridae family. We identified the location of the capsule depolymerase gene of the new phage, which was amplified, cloned, expressed, and purified. The efficacy of the recombinant B1dep depolymerase was tested by spotting on K. pneumoniae strains and it was confirmed that the extract lowers the thickness of the bacterium lawn as it degrades the protective capsule on bacterial cells. As K. pneumoniae strains possessing the K2 serotype have epidemiological importance, the B1 phage and its depolymerase are promising candidates for use as possible antimicrobial agents.

scholarly journals Complete Genome Sequence of Klebsiella pneumoniae Myophage Mineola

2019 ◽  
Vol 8 (17) ◽  
Author(s):  
Justin X. Boeckman ◽  
Lauren Lessor ◽  
Jason J. Gill ◽  
Mei Liu
Keyword(s):  
Drug Resistance ◽  
Klebsiella Pneumoniae ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Human Pathogen ◽  
Content Type ◽  
Isolation And Characterization ◽  
Wide Range

Klebsiella pneumoniae is an important human pathogen due to the wide range of infections it can cause and its emerging drug resistance. Isolation and characterization of phage infecting K. pneumoniae could be important for future therapeutic applications.

Isolation and characterization of a strain of Klebsiella pneumoniae with citrinin-degrading activity

2010 ◽  
Vol 27 (3) ◽  
pp. 487-493 ◽  
Author(s):  
Ya-Hui Chen ◽  
Shyang-Chwen Sheu ◽  
Jeng-Leun Mau ◽  
Pao-Chuan Hsieh
Keyword(s):  
Klebsiella Pneumoniae ◽  
Isolation And Characterization
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