Outer Membrane Proteins of Klebsiella pneumoniae After Exposure to Ciprofloxacin

1998 ◽  
Vol 287 (4) ◽  
pp. 343-346 ◽  
Author(s):  
Anna Hoštacká ◽  
Edita Karelová
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Proteins

scholarly journals Virulence Factors in Hypervirulent Klebsiella pneumoniae

2021 ◽  
Vol 12 ◽  
Author(s):  
Jie Zhu ◽  
Tao Wang ◽  
Liang Chen ◽  
Hong Du
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Virulence Factors ◽  
Outer Membrane Proteins ◽  
Pyogenic Liver Abscess ◽  
Secretion System ◽  
Asian Pacific ◽  
Shed Light ◽  
New Strategies

Hypervirulent Klebsiella pneumoniae (hvKP) has spread globally since first described in the Asian Pacific Rim. It is an invasive variant that differs from the classical K. pneumoniae (cKP), with hypermucoviscosity and hypervirulence, causing community-acquired infections, including pyogenic liver abscess, pneumonia, meningitis, and endophthalmitis. It utilizes a battery of virulence factors for survival and pathogenesis, such as capsule, siderophores, lipopolysaccharide, fimbriae, outer membrane proteins, and type 6 secretion system, of which the former two are dominant. This review summarizes these hvKP-associated virulence factors in order to understand its molecular pathogenesis and shed light on new strategies to improve the prevention, diagnosis, and treatment of hvKP-causing infection.

scholarly journals Energy-Dependent Accumulation of Fluoroquinolones in Quinolone-Resistant Klebsiella pneumoniaeStrains

1998 ◽  
Vol 42 (7) ◽  
pp. 1850-1852 ◽  
Author(s):  
Luis Martínez-Martínez ◽  
Isabel García ◽  
Sofía Ballesta ◽  
Vicente Javier Benedí ◽  
Santiago Hernández-Allés ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Clinical Isolates ◽  
Intracellular Accumulation ◽  
Active Efflux ◽  
Energy Dependent ◽  
Isogenic Strains

The intracellular accumulation of norfloxacin and pefloxacin inKlebsiella pneumoniae was evaluated. The roles of lipopolysaccharide, capsule, and outer membrane proteins were not important for the intrabacterial accumulation of fluoroquinolones in isogenic strains with known outer membrane alterations. In fluoroquinolone-resistant clinical isolates also expressing GyrA alterations, an active efflux leading to decreased accumulation of the drugs enhanced their resistance to these agents.

scholarly journals Resistance of Klebsiella Pneumoniae clinical isolates: linkage of outer membrane proteins (omps) with production esbls

2011 ◽  
Vol 42 (2) ◽  
pp. 467-469
Author(s):  
Lívia Érika Carlos Marques ◽  
Danielle Ferreira de Oliveira ◽  
Márcia Maria Mendes Marques ◽  
Ana Raquel Araújo da Silva ◽  
Carlucio Roberto Alves ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Clinical Isolates

scholarly journals Surface Antigen Exposure by Bismuth Dimercaprol Suppression of Klebsiella pneumoniae Capsular Polysaccharide

1999 ◽  
Vol 67 (2) ◽  
pp. 664-669 ◽  
Author(s):  
Philip Domenico ◽  
J. M. Tomas ◽  
S. Merino ◽  
X. Rubires ◽  
Burke A. Cunha
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Capsular Polysaccharide ◽  
Outer Membrane Proteins ◽  
Defined Medium ◽  
Phagocytic Index ◽  
Dependent Manner ◽  
O Antigen ◽  
Bacterial Capsule

ABSTRACT The bacterial capsule is an important virulence determinant in animal and plant disease. Bacterial capsule and slime can be inhibited by bismuth compounds, especially when complexed with lipophilic thiol chelators. Bismuth dimercaprol (BisBAL) at 1 ppm of Bi3+repressed Klebsiella pneumoniae capsule expression in defined medium by nearly 90%, which exposed subsurface structures. The phagocytic index for BisBAL-treated bacteria increased from <10 to 360 bacteria per 100 neutrophils in the presence of complement and anticapsular or anti-O antigen antiserum. BisBAL treatment also enhanced the reactivity of monoclonal antibodies (MAbs) specific for the O1-antigen lipopolysaccharide (LPS) or the LPS core in a dose-dependent manner as indicated by the results of enzyme-linked immunosorbent assays. When anti-O1 MAb was used, the reactivity increased significantly for fully encapsulated O1:K1 or O1:K2 cells but not for O1:K− cells. Deposition of C3b also increased significantly for BisBAL-treated O1:K1 or O1:K2 cells but not for O1:K− cells. Survival of a serum-sensitive strain was <0.1% when nonimmune human serum absorbed with O1:K1 cells was used and 107% when BisBAL-treated cells were used for absorption. Outer membrane proteins were also more accessible on the surface of K. pneumoniae after BisBAL treatment. Thus, at subinhibitory levels, BisBAL inhibited capsule expression, which promoted phagocytosis, enhanced the reactivity of specific antibodies for LPS O antigen, LPS core epitopes, or outer-membrane proteins, and enhanced complement interaction with encapsulated K. pneumoniae. By unmasking bacterial surface structures and enhancing the immune system reactivity to bacteria, bismuth thiols may prove useful as adjuncts for vaccination.

scholarly journals Roles of β-Lactamases and Porins in Activities of Carbapenems and Cephalosporins against Klebsiella pneumoniae

1999 ◽  
Vol 43 (7) ◽  
pp. 1669-1673 ◽  
Author(s):  
Luis Martínez-Martínez ◽  
Alvaro Pascual ◽  
Santiago Hernández-Allés ◽  
Dolores Alvarez-Díaz ◽  
Ana Isabel Suárez ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Extended Spectrum ◽  
Inoculum Effect

ABSTRACT Two clinical isolates of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae were noted to be less susceptible than expected to imipenem. Both were missing outer membrane proteins that serve as channels for antibiotic entry. The role of β-lactamase in resistance was investigated by eliminating the original ESBL and introducing plasmids encoding various ESBLs and AmpC β-lactamase types, by studying the effect of an increased inoculum, and by evaluating interactions with β-lactamase inhibitors. The contribution of porin deficiency was investigated by restoring a functional ompK36 gene on a plasmid. Plasmids encoding AmpC-type β-lactamases provided resistance to imipenem (up to 64 μg/ml) and meropenem (up to 16 μg/ml) in strains deficient in porins. Carbapenem resistance showed little inoculum effect, was not affected by clavulanate but was blocked by BRL 42715, and was diminished if OmpK36 porin was restored. Plasmids encoding TEM- and SHV-type ESBLs conferred resistance to cefepime and cefpirome, as well as to earlier oxyimino-β-lactams. This resistance was magnified with an increased inoculum, was blocked by clavulanate, and was also lowered by OmpK36 porin restoration. In addition, SHV-2 β-lactamase had a small effect on carbapenem resistance (imipenem MIC, 4 μg/ml, increasing to 16 μg/ml with a higher inoculum) when porins were absent. In K. pneumoniae porin loss can thus augment resistance provided either by TEM- or SHV-type ESBLs or by plasmid-mediated AmpC enzymes to include the latest oxyimino-β-lactams and carbapenems.

scholarly journals Emergence of Oxacillinase-Mediated Resistance to Imipenem in Klebsiella pneumoniae

2004 ◽  
Vol 48 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Laurent Poirel ◽  
Claire Héritier ◽  
Venus Tolün ◽  
Patrice Nordmann
Keyword(s):  
Membrane Proteins ◽  
Klebsiella Pneumoniae ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Amino Acid Identity ◽  
Cloning And Expression ◽  
Class 1 Integron ◽  
Class 1 ◽  
High Level ◽  
Level Resistance

ABSTRACT Klebsiella pneumoniae strain 11978 was isolated in Turkey in 2001 and was found to be resistant to all β-lactams, including carbapenems. Cloning and expression in Escherichia coli identified five β-lactamases, including two novel oxacillinases. The β-lactamase OXA-48 hydrolyzed imipenem at a high level and was remotely related (less than 46% amino acid identity) to the other oxacillinases. It hydrolyzed penicillins and imipenem but not expanded-spectrum cephalosporins. The bla OXA-48 gene was plasmid encoded and not associated with an integron, in contrast to most of the oxacillinase genes. An insertion sequence, IS1999, was found immediately upstream of bla OXA-48. Another plasmid that encoded a second oxacillinase gene, bla OXA-47, located inside a class 1 integron was identified in K. pneumoniae 11978. OXA-47 had a narrow spectrum of hydrolysis activity and did not hydrolyze ceftazidime or imipenem, as is found for the β-lactamase (OXA-1) to which it is related. In addition, β-lactamases TEM-1 and SHV-2a were expressed from the same K. pneumoniae isolate. Analysis of the outer membrane proteins of this isolate revealed that it lacked a porin of ca. 36 kDa. Thus, the high-level resistance to β-lactams of this clinical isolate resulted from peculiar β-lactamases and modification of outer membrane proteins.

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