Two ABC transporter operons and the antimicrobial resistance gene mtrF are pilT responsive in Neisseria gonorrhoeae.
Ontology highlight
ABSTRACT:
SUBMITTER: Friedrich A
PROVIDER: S-EPMC1951848 | biostudies-literature | 2007 Jul
REPOSITORIES: biostudies-literature
Publications
Two ABC transporter operons and the antimicrobial resistance gene mtrF are pilT responsive in Neisseria gonorrhoeae.
Friedrich Alexandra A Arvidson Cindy G CG Shafer William M WM Lee Eun-Hee EH So Magdalene M
Journal of bacteriology 20070511 14
Retraction of type IV pili is mediated by PilT. We show that loss of pilT function leads to upregulation of mtrF (multiple transferable resistance) and two operons encoding putative ABC transporters in Neisseria gonorrhoeae MS11. This effect occurs indirectly through the transcriptional regulator FarR, which until now has been shown to regulate only farAB. L-Glutamine can reverse pilT downregulation of the ABC transporter operons and mtrF. ...[more]
Similar Datasets
Project description:The obligate human pathogen Neisseria gonorrhoeae uses the MtrC-MtrD-MtrE efflux pump to resist structurally diverse hydrophobic antimicrobial agents (HAs), some of which bathe mucosal surfaces that become infected during transmission of gonococci. Constitutive high-level HA resistance occurs by the loss of a repressor (MtrR) that negatively controls transcription of the mtrCDE operon. This high-level HA resistance also requires the product of the mtrF gene, which is located downstream and transcriptionally divergent from mtrCDE. MtrF is a putative inner membrane protein, but its role in HA resistance mediated by the MtrC-MtrD-MtrE efflux pump remains to be determined. High-level HA resistance can also be mediated through an induction process that requires enhanced transcription of mtrCDE when gonococci are grown in the presence of a sublethal concentration of Triton X-100. We now report that inactivation of mtrF results in a significant reduction in the induction of HA resistance and that the expression of mtrF is enhanced when gonococci are grown under inducing conditions. However, no effect was observed on the induction of mtrCDE expression in an MtrF-negative strain. The expression of mtrF was repressed by MtrR, the major repressor of mtrCDE expression. In addition to MtrR, another repressor (MpeR) can downregulate the expression of mtrF. Repression of mtrF by MtrR and MpeR was additive, demonstrating that the repressive effects mediated by these regulators are independent processes.
| S-EPMC1112036 | biostudies-literature
Project description:The ATPase protein PilT mediates retraction of type IV pili (Tfp). Tfp retraction of Neisseria gonorrhoeae causes many signal transduction events and changes in gene expression in infected epithelial cells. To find out whether a pilT mutation and lack of Tfp retraction, respectively, lead also to gene regulation in bacteria, we performed microarrays comparing the transcriptional profiles of the N. gonorrhoeae parent strain MS11 and its isogenic pilT mutant during growth in vitro. A loss-of-function-mutation in pilT led to altered transcript levels of 63 ORFs. Levels of pilE transcripts and its deduced protein, the major Tfp subunit pilin, were increased most markedly by a mutation in pilT. Further studies revealed that pilE expression was also controlled by two other genes encoding Tfp biogenesis proteins, pilD and pilF. Our studies strongly suggest that pilE expression is a finely tuned process.
| S-EPMC4428587 | biostudies-literature
Project description:Neisseria gonorrhoeae is an obligate human pathogen and the causative agent of the sexually transmitted disease gonorrhea. The control of this disease has been compromised by the increasing proportion of infections due to antibiotic-resistant strains, which are growing at an alarming rate. N. gonorrhoeae MtrF is an integral membrane protein that belongs to the AbgT family of transporters for which no structural information is available. Here, we describe the crystal structure of MtrF, revealing a dimeric molecule with architecture distinct from all other families of transporters. MtrF is a bowl-shaped dimer with a solvent-filled basin extending from the cytoplasm to halfway across the membrane bilayer. Each subunit of the transporter contains nine transmembrane helices and two hairpins, posing a plausible pathway for substrate transport. A combination of the crystal structure and biochemical functional assays suggests that MtrF is an antibiotic efflux pump mediating bacterial resistance to sulfonamide antimetabolite drugs.
| S-EPMC4410016 | biostudies-literature
Project description:The ATPase protein PilT mediates retraction of type IV pili. We performed microarrays comparing the transcription profile of the Neisseria gonorrhoeae wild-type strain MS11 and its isogenic pilT mutant. 63 open reading frames were found to be differentially regulated in the pilT mutant. Most interestingly, a loss of function mutation in pilT leads to an upregulation of pilE, which encodes the pilus subunit protein.
2008-09-01 | GSE12258 | GEO
Project description:Post-translational acetylation is a common protein modification in bacteria. It was recently reported that Neisseria gonorrhoeae acetylates the Type IV pilus retraction motor, PilT. Here, we show recombinant PilT can be acetylated in vitro and acetylation does not affect PilT ultrastructure. To investigate the function of PilT acetylation, we mutated an acetylated lysine, K117, to mimic its acetylated or unacetylated forms. These mutations were not tolerated by wild-type N. gonorrhoeae, but they were tolerated by N. gonorrhoeae carrying an inducible pilE when grown without inducer. We identified additional mutations in pilT and pilU that suppress the lethality of K117 mutations. To investigate the link between PilE and PilT acetylation, we found the lack of PilE decreases PilT acetylation levels and increases the amount of PilT associated with the inner membrane. Finally, we found no difference between wild-type and mutant cells in transformation efficiency, suggesting neither mutation inhibits Type IV pilus retraction. Mutant cells, however, form microcolonies morphologically distinct from wt cells. We conclude that interfering with the acetylation status of PilTK117 greatly reduces N. gonorrhoeae viability, and mutations in pilT, pilU and pilE can overcome this lethality. We discuss the implications of these findings in the context of Type IV pilus retraction regulation.
| S-EPMC6214798 | biostudies-literature
Project description:BackgroundThe mal genes that encode maltose transporters have undergone extensive lateral transfer among ancestors of the archaea Thermococcus litoralis and Pyrococcus furiosus. Bacterial hyperthermophiles of the order Thermotogales live among these archaea and so may have shared in these transfers. The genome sequence of Thermotoga maritima bears evidence of extensive acquisition of archaeal genes, so its ancestors clearly had the capacity to do so. We examined deep phylogenetic relationships among the mal genes of these hyperthermophiles and their close relatives to look for evidence of shared ancestry.ResultsWe demonstrate that the two maltose ATP binding cassette (ABC) transporter operons now found in Tc. litoralis and P. furiosus (termed mal and mdx genes, respectively) are not closely related to one another. The Tc. litoralis and P. furiosus mal genes are most closely related to bacterial mal genes while their respective mdx genes are archaeal. The genes of the two mal operons in Tt. maritima are not related to genes in either of these archaeal operons. They are highly similar to one another and belong to a phylogenetic lineage that includes mal genes from the enteric bacteria. A unique domain of the enteric MalF membrane spanning proteins found also in these Thermotogales MalF homologs supports their relatively close relationship with these enteric proteins. Analyses of genome sequence data from other Thermotogales species, Fervidobacterium nodosum, Thermosipho melanesiensis, Thermotoga petrophila, Thermotoga lettingae, and Thermotoga neapolitana, revealed a third apparent mal operon, absent from the published genome sequence of Tt. maritima strain MSB8. This third operon, mal3, is more closely related to the Thermococcales' bacteria-derived mal genes than are mal1 and mal2. F. nodosum, Ts. melanesiensis, and Tt. lettingae have only one of the mal1-mal2 paralogs. The mal2 operon from an unknown species of Thermotoga appears to have been horizontally acquired by a Thermotoga species that had only mal1.ConclusionThese data demonstrate that the Tc. litoralis and P. furiosus mdx maltodextrin transporter operons arose in the Archaea while their mal maltose transporter operons arose in a bacterial lineage, but not the same lineage as the two maltose transporter operons found in the published Tt. maritima genome sequence. These Tt. maritima maltose transporters are phylogenetically and structurally similar to those found in enteric bacteria and the mal2 operon was horizontally transferred within the Thermotoga lineage. Other Thermotogales species have a third mal operon that is more closely related to the bacterial Thermococcales mal operons, but the data do not support a recent horizontal sharing of that operon between these groups.
| S-EPMC2246101 | biostudies-literature
Project description:Previous studies have shown that the MpeR transcriptional regulator produced by Neisseria gonorrhoeae represses the expression of mtrF, which encodes a putative inner membrane protein (MtrF). MtrF works as an accessory protein with the Mtr efflux pump, helping gonococci to resist high levels of diverse hydrophobic antimicrobials. Regulation of mpeR has been reported to occur by an iron-dependent mechanism involving Fur (ferric uptake regulator). Collectively, these observations suggest the presence of an interconnected regulatory system in gonococci that modulates the expression of efflux pump protein-encoding genes in an iron-responsive manner. Herein, we describe this connection and report that levels of gonococcal resistance to a substrate of the mtrCDE-encoded efflux pump can be modulated by MpeR and the availability of free iron. Using microarray analysis, we found that the mtrR gene, which encodes a direct repressor (MtrR) of mtrCDE, is an MpeR-repressed determinant in the late logarithmic phase of growth when free iron levels would be reduced due to bacterial consumption. This repression was enhanced under conditions of iron limitation and resulted in increased expression of the mtrCDE efflux pump operon. Furthermore, as judged by DNA-binding analysis, MpeR-mediated repression of mtrR was direct. Collectively, our results indicate that both genetic and physiologic parameters (e.g., iron availability) can influence the expression of the mtr efflux system and modulate levels of gonococcal susceptibility to efflux pump substrates.
| S-EPMC3294918 | biostudies-literature
Project description:Antimicrobial resistance (AMR) in Neisseria gonorrhoeae is a global concern. Phylogenetic analyses resolve uncertainties regarding genetic relatedness of isolates with identical phenotypes and inform whether AMR is due to new mutations and clonal expansion or separate introductions by importation. We sequenced 1,277 isolates with associated epidemiologic and antimicrobial susceptibility data collected during 2013-2016 to investigate N. gonorrhoeae genomic variability in England. Comparing genetic markers and phenotypes for AMR, we identified 2 N. gonorrhoeae lineages with different antimicrobial susceptibility profiles and 3 clusters with elevated MICs for ceftriaxone, varying mutations in the penA allele, and different epidemiologic characteristics. Our results indicate N. gonorrhoeae with reduced antimicrobial susceptibility emerged independently and multiple times in different sexual networks in England, through new mutation or recombination events and by importation. Monitoring and control for AMR in N. gonorrhoeae should cover the entire population affected, rather than focusing on specific risk groups or locations.
| S-EPMC7045833 | biostudies-literature
Project description:BackgroundIn Canada, gonorrhea is the second most prevalent bacterial sexually transmitted infection. The Gonococcal Antimicrobial Surveillance Programme (GASP - Canada), a passive surveillance system monitoring antimicrobial resistance in Neisseria gonorrhoeae in Canada since 1985, is the source for this summary of demographics, antimicrobial resistance and N. gonorrhoeae multi-antigen sequence typing (NG-MAST) of gonococcal isolates collected in Canada in 2021.MethodsProvincial and territorial public health laboratories submitted N. gonorrhoeae cultures and data to the National Microbiology Laboratory in Winnipeg as part of the surveillance system. The antimicrobial resistance and molecular type of each isolate received were determined.ResultsIn total, 3,439 N. gonorrhoeae cultures were received from laboratories across Canada in 2021, a 9.9% increase since 2020 (n=3,130). Decreased susceptibility to cefixime increased significantly (p<0.001) in 2021 (1.5%) compared to 2017 (0.6%). No significant change in decreased susceptibility to ceftriaxone was detected between 2017 and 2021 (0.6%) (p>0.001); however, one ceftriaxone-resistant isolate was identified. Azithromycin resistance decreased significantly (p<0.001) in 2021 (7.6%) compared to 2017 (11.7%); however, there was a significant increase (p<0.001) in the proportion of cultures with an azithromycin minimum inhibitory concentration of at least 1 mg/L (2017=22.2% to 2021=28.1%). In 2021, NG-MAST-19875 (15.3%) was the most prevalent sequence type in Canada; 20.3% of isolates with this sequence type were resistant to azithromycin.ConclusionThe spread of antimicrobial-resistant gonorrhea is a significant public health concern. The continued regional and national surveillance of antimicrobial resistance in N. gonorrhoeae is essential in ensuring effective treatment therapies are recommended.
| S-EPMC10919915 | biostudies-literature
Project description:Neisseria gonorrhoeae antimicrobial resistance (AMR) is a globally recognized health threat; new strategies are needed to enhance AMR surveillance. The Northern Territory of Australia is unique in that 2 different first-line therapies, based primarily on geographic location, are used for gonorrhea treatment. We tested 1,629 N. gonorrhoeae nucleic acid amplification test-positive clinical samples, collected from regions where ceftriaxone plus azithromycin or amoxicillin plus azithromycin are recommended first-line treatments, by using 8 N. gonorrhoeae AMR PCR assays. We compared results with those from routine culture-based surveillance data. PCR data confirmed an absence of ceftriaxone resistance and a low level of azithromycin resistance (0.2%), and that penicillin resistance was <5% in amoxicillin plus azithromycin regions. Rates of ciprofloxacin resistance and penicillinase-producing N. gonorrhoeae were lower when molecular methods were used. Molecular methods to detect N. gonorrhoeae AMR can increase the evidence base for treatment guidelines, particularly in settings where culture-based surveillance is limited.
| S-EPMC5572890 | biostudies-literature