scholarly journals Implications of Phase Variation of a Gene (pgtA) Encoding a Pilin Galactosyl Transferase in Gonococcal Pathogenesis

2002 ◽  
Vol 196 (2) ◽  
pp. 147-162 ◽  
Author(s):  
Asesh Banerjee ◽  
Rong Wang ◽  
Sherry L. Supernavage ◽  
Salil K. Ghosh ◽  
James Parker ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Building Block ◽  
Phase Variation ◽  
Clinical Isolates ◽  
Gonococcal Infection ◽  
Homopolymeric Tract ◽  
Galactosyl Transferase ◽  
Gc Gene ◽  
Uncomplicated Gonorrhea

The pilin glycoprotein (PilE) is the main building block of the pilus of Neisseria gonorrhoeae (gonococcus [GC]). GC pilin is known to carry a disaccharide O-glycan, which has an αGal attached to the O-linked GlcNAc by a 1–3 glycosidic bond. In this report, we describe the cloning and characterization of the GC gene, pilus glycosyl transferase A (pgtA), which encodes the galactosyl transferase that catalyzes the synthesis of this Gal–GlcNAc bond of pilin glycan. A homopolymeric tract of Gs (poly-G) is present in the pgtA gene of many GC strains, and this pgtA with poly-G can undergo phase variation (Pv). However, in many other GC, pgtA lacks the poly-G and is expressed constitutively without Pv. Furthermore, by screening a large number of clinical isolates, a significant correlation was observed between the presence of poly-G in pgtA and the dissemination of GC infection. Poly-G was found in pgtA in all (24 out of 24) of the isolates from patients with disseminated gonococcal infection (DGI). In contrast, for the vast majority (20 out of 28) of GC isolated from uncomplicated gonorrhea (UG) patients, pgtA lacked the poly-G. These results indicate that Pv of pgtA is likely to be involved in the conversion of UG to DGI.

scholarly journals Serotype and serovar distribution of Neisseria gonorrhoeae isolated from high-risk populations in Bangladesh

2013 ◽  
Vol 38 (3) ◽  
pp. 114-118
Author(s):  
MA Alam ◽  
MZ Chowdhury ◽  
F Ahmed ◽  
A Alam ◽  
MA Hossain
Keyword(s):  
High Risk ◽  
Neisseria Gonorrhoeae ◽  
Control Strategy ◽  
Multidrug Resistant ◽  
Contact Tracing ◽  
Gonococcal Infection ◽  
Sexual Network ◽  
High Risk Populations ◽  
Serotype B

Neisseria gonorrhoeae, the causative agent of gonococcal infection, is known to frequently change their characteristics to evade host immune mechanism. Characterization of the clinical isolates of the organism can lead to identification of the circulating strains and often a sexual network in a community to help in designing the control strategy. Keeping in mind the above consideration, a total of 239 N. gonorrhoeae, isolated from high-risk populations, were characterized for serotypes and serovars by monoclonal antibodies against protein I of the organism. Majority of the serotypes were serotype B (142, 59.4%). Majority of the isolates showing resistance to at least one of the antibiotics tested were also serotype B (139, 59.2%), whereas, majority of the isolates showing resistance to any three of the antibiotics (multidrug resistant, MDR) (63%) was serotype A. A total of 41 different serovars were also identified and five of which (Arst, Bropt, Bopt, Arost, and Brop) included the highest percent (49.3%) of the isolates. Many serovars (23/41, 56.1%) were new emergent and included 58 (24.3%) of the isolates investigated. All of the new serovars were resistant to at least one of the antibiotics tested and the highest rate (40/102, 39.2%) was MDR. Serotyping and serovar determination was found contributory to understand the microepidemics of the N. gonorrhoeae isolates. Further studies including antibiogram and contact tracing can efficiently help in control of the disease. DOI: http://dx.doi.org/10.3329/bmrcb.v38i3.14339 Bangladesh Med Res Counc Bull 2012; 38(3): 114-118 (December)

scholarly journals Conservation of the lipooligosaccharide synthesis locus lgt among strains of Neisseria gonorrhoeae: requirement for lgtE in synthesis of the 2C7 epitope and of the beta chain of strain 15253.

1996 ◽  
Vol 184 (4) ◽  
pp. 1233-1241 ◽  
Author(s):  
A L Erwin ◽  
P A Haynes ◽  
P A Rice ◽  
E C Gotschlich
Keyword(s):  
Structural Analysis ◽  
Neisseria Gonorrhoeae ◽  
Phase Variation ◽  
Deletion Mutants ◽  
Beta Chain ◽  
Alpha Chain ◽  
Glycosyl Transferases ◽  
Galactosyl Transferase ◽  
Glcnac Transferase

The present study was undertaken to examine the extent to which the lgt locus varies among strains of gonococci. This locus encodes five glycosyl transferases involved in the synthesis of the lipooligosaccharide (LOS) of Neisseria gonorrhoeae. We examined seven gonococcal strains and found that the structure of the lgt locus is conserved among six of these strains. The locus is strikingly altered in strain 15253. This is one of the few strains where extensive structural analysis of its LOS is available, and therefore, we defined the altered lgt locus and focused on the reactivity of mAB 2C7. We found that strain 15253 contains only two lgt genes, lgtA and lgtE. As in F62, lgtA encodes a GlcNAc transferase and is subject to phase variation. In addition, by analysis of deletion mutants, we found that lgtE, which encodes a galactosyl transferase that is required for elongating the alpha-chain, is also necessary for completing the beta chain.

scholarly journals Characterization of Neisseria gonorrhoeae protein II phase variation by use of monoclonal antibodies.

1984 ◽  
Vol 45 (2) ◽  
pp. 453-457 ◽  
Author(s):  
W J Black ◽  
R S Schwalbe ◽  
I Nachamkin ◽  
J G Cannon
Keyword(s):  
Monoclonal Antibodies ◽  
Neisseria Gonorrhoeae ◽  
Phase Variation

scholarly journals Phenotypic and molecular characterization of Acinetobacter baumannii clinical isolates in Saudi Arabia

2020 ◽  
Vol 13 (2) ◽  
pp. 327
Author(s):  
R Bawazeer ◽  
M Algoribi ◽  
T Abujamel ◽  
L Okdah ◽  
M Alzayer ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Acinetobacter Baumannii ◽  
Molecular Characterization ◽  
Clinical Isolates

scholarly journals Molecular characterization of a ceftriaxone-resistant Neisseria gonorrhoeae strain found in Switzerland: a case report

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Konrad Egli ◽  
Anna Roditscheff ◽  
Ursula Flückiger ◽  
Martin Risch ◽  
Lorenz Risch ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
23S Rrna ◽  
Rrna Gene ◽  
Limited Information ◽  
Specific Pcr ◽  
Appropriate Treatment ◽  
23S Rrna Gene ◽  
Allele Type ◽  
Ciprofloxacin Resistance

Abstract Background The resistance of Neisseria gonorrhoeae to ceftriaxone is unusual in Switzerland. The underlying genotype responsible for resistance is suspected to be novel. Generally, resistance in Neisseria gonorrhoeae (Ng) involves a comprehensive set of genes with many different mutations leading to resistance to different β-lactams and fluoroquinolones. Case presentation A patient had a positive result from specific PCR for Ng. We routinely culture all clinical specimens with a positive NG-PCR. In this particular case, we isolated a strain with resistance to ceftriaxone in Switzerland. A total of seven different genes (penA, ponA, porinB, mtr, gyrA, parC, 23S rRNA gene) in this strain were partially sequenced for comparison with phenotypic susceptibility testing. Interestingly, two different mutations in the porinB gene were observed, and data on this gene are limited. Information on the identified allele type of the penA gene is very limited as well. Three different mutations of parC and gyrA that correlate with ciprofloxacin resistance were found. The combination of ceftriaxone and ciprofloxacin resistance makes an appropriate treatment difficult to obtain due to multidrug resistance. Conclusion The combined results for all genes show the appearance of new mutations in central Europe either due to worldwide spread or the emergence of new genetic combinations of mutations.

Sign in / Sign up

Export Citation Format

Share Document