Analysis of the NH2-Terminal 83rd Amino Acid of Escherichia coli GyrA in Quinolone-Resistance

Artificial mutations of Gyrase A protein (GyrA) in Escherichia coli by site-directed mutagenesis were generated to analyze quinolone-resistant mechanisms. By genetic analysis of gyrA genes in a gyrA temperature sensitive (Ts) background, exchange of Ser at the NH₂-terminal 83rd position of GyrA to Trp, Leu, Phe, Tyr, Ala, Val, and Ile caused bacterial resistance to the quinolones, while exchange to Gly, Asn, Lys, Arg and Asp did not confer resistance. These results indicate that it is the most important for the 83rd amino acid residue to be hydrophobic in expressing the phenotype of resistance to the quinolones. These findings also suggest that the hydroxyl group of Ser would not play a major role in the quinolone-gyrase interaction and Ser83 would not interact directly with other amino acid residues.     

Amino Acid Substitutions in GyrA of Burkholderia glumae Are Implicated in Not Only Oxolinic Acid Resistance but Also Fitness on Rice Plants

Oxolinic acid (OA) resistance in field isolates of Burkholderia glumae, a causal agent of bacterial grain rot, is dependent on an amino acid substitution at position 83 in GyrA (GyrA83). In the present study, among spontaneous in vitro mutants from the OA-sensitive B. glumae strain Pg-10, we selected OA-resistant mutants that emerged at a rate of 5.7 × 10⁻¹⁰. Nucleotide sequence analysis of the quinolone resistance-determining region in GyrA showed that Gly81Cys, Gly81Asp, Asp82Gly, Ser83Arg, Asp87Gly, and Asp87Asn are observed in these OA-resistant mutants. The introduction of each amino acid substitution into Pg-10 resulted in OA resistance, similar to what was observed for mutants with the responsible amino acid substitution. In vitro growth of recombinants with Asp82Gly was delayed significantly compared to that of Pg-10; however, that of the other recombinants did not differ significantly. The inoculation of each recombinant into rice spikelets did not result in disease. In inoculated rice spikelets, recombinants with Ser83Arg grew less than Pg-10 during flowering, and growth of the other recombinants was reduced significantly. On the other hand, the reduced growth of recombinants with Ser83Arg in spikelets was compensated for under OA treatment, resulting in disease. These results suggest that amino acid substitutions in GyrA of B. glumae are implicated in not only OA resistance but also fitness on rice plants. Therefore, GyrA83 substitution is thought to be responsible for OA resistance in B. glumae field isolates.     

Relationship between gyrA Mutations and Quinolone Resistance in Flavobacterium psychrophilum Isolates

Flavobacterium psychrophilum is the causative agent of the fish diseases called bacterial cold-water disease and rainbow trout fry syndrome. It has been reported that some isolates of F. psychrophilum are resistant to quinolones; however, the mechanism of this quinolone resistance has been unexplained. In this study, we examined the quinolone susceptibility patterns of 27 F. psychrophilum strains isolated in Japan and the United States. Out of 27 isolates, 14 were resistant to both nalidixic acid (NA) and oxolinic acid (OXA), and the others were susceptible to NA and OXA. When amino acid sequences deduced from gyrA nucleotide sequences of all isolates tested were analyzed, two amino acid substitutions (a threonine residue replaced by an alanine or isoleucine residue in position 83 of GyrA [Escherichia coli numbering] and an aspartic acid residue replaced by a tyrosine residue in position 87) were observed in the 14 quinolone-resistant isolates. These results strongly suggest that, as in other gram-negative bacteria, DNA gyrase is an important target for quinolones in F. psychrophilum.     

WQ-3810 exerts high inhibitory effect on quinolone-resistant DNA gyrase of Salmonella Typhimurium

ABSTRACT

The inhibitory effect of WQ-3810 on DNA gyrase was assayed to evaluate the potential of WQ-3810 as a candidate drug for the treatment of quinolone resistant Salmonella Typhymurium infection. The inhibitory effect of WQ-3810, ciprofloxacin and nalidixic acid was compared by accessing the drug concentration that halves the enzyme activity (IC₅₀) of purified S. Typhimurium wildtype and mutant DNA gyrase with amino acid substitution at position 83 or/and 87 in subunit A (GyrA) causing quinolone resistance. As a result, WQ-3810 reduced the enzyme activity of both wildtype and mutant DNA gyrase at a lower concentration than ciprofloxacin and nalidixic acid. Remarkably, WQ-3810 showed a higher inhibitory effect on DNA gyrase with amino acid substitutions at position 87 than with that at position 83 in GyrA. This study revealed that WQ-3810 could be an effective therapeutic agent, especially against quinolone resistant Salmonella enterica having amino acid substitution at position 87.     

Fluoroquinolone resistance in Helicobacter pylori: role of mutations at position 87 and 91 of GyrA on the level of resistance and identification of a resistance conferring mutation in GyrB

Background and Aims: Fluoroquinolone‐containing regimens have been suggested as an alternate to standard triple therapy for the treatment of Helicobacter pylori infections. To determine the relationship between fluoroquinolone resistance and mutations of GyrA and GyrB in H. pylori, we exchanged the mutations at positions 87and 91 of GyrA among fluoroquinolone‐resistant clinical isolates. GyrB of a strain with no mutations in GyrA was also analyzed to identify mechanisms of resistance to norfloxacin. Materials & Methods: Natural transformation was performed using the amplified fragment of the gyrA and gyrB gene as donor DNA. The amino acid sequences of GyrA and GyrB were determined by DNA sequencing of the gyrA and gyrB genes. Results: Norfloxacin‐resistant strains which had mutations at position 87 and 91 became susceptible when the mutations were converted to the wild type. When the mutation from Asp to Asn at position 91 was exchanged to the mutation from Asn to Lys at position 87, the MIC to levofloxacin, gatifloxacin, and sitafloxacin increased. Norfloxacin‐resistant strain TS132 with no mutations in GyrA but had a mutation at position 463 in GyrB. Transformants obtained by natural transformation using gyrB DNA of TS132 had a mutation at position 463 of GyrB and revealed resistant to norfloxacin and levofloxacin. Conclusion: Mutation from Asn to Lys at position 87 of GyrA confers higher resistance to levofloxacin and gatifloxacin than does mutation from Asp to Asn at position 91. We propose that mutation at position 463 in GyrB as a novel mechanism of fluoroquinolone resistance in H. pylori.     

Quinolone-resistant mutations of the gyrA gene of Escherichia coli

Summary DNA fragments of 8.5 kb containing the gyrA gene were cloned from Escherichia coli KL-16 and from four spontaneous gyrA mutants which showed various levels of resistance to quinolones. The gyrA gene was situated at about 4 kb in front of the nrdA gene and transcribed counterclockwise on the E. coli chromosome. It encoded a polypeptide of 875 amino acids with a molecular weight of about 97000. The four gyrA mutations were located strikingly close to one another within a small region near the N-terminus of the gyrA polypeptide, i.e., nucleotide changes from C to T, from C to G, from G to T and from G to T at nucleotides 248, 248, 318 and 199, respectively, resulting in amino acid changes from Ser to Leu, from Ser to Trp, from Gln to His and from Ala to Ser at amino acids 83, 83, 106 and 67, respectively. These mutations were situated in the relatively hydrophilic regions of the GyrA polypeptide and close to Tyr at amino acid 122 which has been shown to be the site covalently bound to DNA.     

Amino acid substitutions in GyrA of Burkholderia glumae are implicated in not only oxolinic acid resistance but also fitness on rice plants

Oxolinic acid (OA) resistance in field isolates of Burkholderia glumae, a causal agent of bacterial grain rot, is dependent on an amino acid substitution at position 83 in GyrA (GyrA83). In the present study, among spontaneous in vitro mutants from the OA-sensitive B. glumae strain Pg-10, we selected OA-resistant mutants that emerged at a rate of 5.7 x 10(-10). Nucleotide sequence analysis of the quinolone resistance-determining region in GyrA showed that Gly81Cys, Gly81Asp, Asp82Gly, Ser83Arg, Asp87Gly, and Asp87Asn are observed in these OA-resistant mutants. The introduction of each amino acid substitution into Pg-10 resulted in OA resistance, similar to what was observed for mutants with the responsible amino acid substitution. In vitro growth of recombinants with Asp82Gly was delayed significantly compared to that of Pg-10; however, that of the other recombinants did not differ significantly. The inoculation of each recombinant into rice spikelets did not result in disease. In inoculated rice spikelets, recombinants with Ser83Arg grew less than Pg-10 during flowering, and growth of the other recombinants was reduced significantly. On the other hand, the reduced growth of recombinants with Ser83Arg in spikelets was compensated for under OA treatment, resulting in disease. These results suggest that amino acid substitutions in GyrA of B. glumae are implicated in not only OA resistance but also fitness on rice plants. Therefore, GyrA83 substitution is thought to be responsible for OA resistance in B. glumae field isolates.     

Quinolone Resistance Mechanisms among Extended-Spectrum Beta-Lactamase (ESBL) Producing Escherichia coli Isolated from Rivers and Lakes in Switzerland

Sixty extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from rivers and lakes in Switzerland were screened for individual strains additionally exhibiting a reduced quinolone susceptibility phenotype. Totally, 42 such isolates were found and further characterized for their molecular (fluoro)quinolone resistance mechanisms. PCR and sequence analysis were performed to identify chromosomal mutations in the quinolone resistance-determining regions (QRDR) of gyrA, gyrB, parC and parE and to describe the occurrence of the following plasmid-mediated quinolone resistance genes: qepA, aac-6′-Ib-cr, qnrA, qnrB, qnrC, qnrD and qnrS. The contribution of efflux pumps to the resistance phenotype of selected strains was further determined by the broth microdilution method in the presence and absence of the efflux pump inhibitor phe-arg-β-naphthylamide (PAβN). Almost all strains, except two isolates, showed at least one mutation in the QRDR of gyrA. Ten strains showed only one mutation in gyrA, whereas thirty isolates exhibited up to four mutations in the QRDR of gyrA, parC and/or parE. No mutations were detected in gyrB. Most frequently the amino-acid substitution Ser83→Leu was detected in GyrA followed by Asp87→Asn in GyrA, Ser80→Ile in ParC, Glu84→Val in ParC and Ser458→Ala in ParE. Plasmid-mediated quinolone resistance mechanisms were found in twenty isolates bearing QnrS1 (4/20), AAC-6′-Ib-cr (15/20) and QepA (1/20) determinants, respectively. No qnrA, qnrB, qnrC and qnrD were found. In the presence of PAβN, the MICs of nalidixic acid were decreased 4- to 32-fold. (Fluoro) quinolone resistance is due to various mechanisms frequently associated with ESBL-production in E. coli from surface waters in Switzerland.     

High level of quinolone resistance in <Emphasis Type="Italic">Escherichia coli</Emphasis> from healthy chicken broilers

The development of resistance to quinolones (nalidixic acid, ciprofloxacin and enrofloxacin) in 2006–2008 was evaluated in 317 strains of Escherichia coli isolated from healthy chicken broilers from various farms. The isolates (2006/2007/2008) showed a high resistance to nalidixic acid (87/85/67 %), ciprofloxacin (CIP) (49/54/29 %) and enrofloxacin (ENR) (52/42/22 %). Nalidixic acid-resistant isolates with low level of MIC for CIP and ENR represented a single mutation; intermediary MIC for CIP and ENR were related to two mutations and high level resistance MIC for CIP (≥4 mg/L) and ENR (≥16 mg/L) represented three mutations (two in gyrA and one in parC). There was a correlation between the phenotype reading of high-level resistance and mutations in gyrA (Ser83Leu, Asp87Tyr or Asp87Asn) and parC (Ser80Ile) gene. Plasmid-mediated quinolone-resistance qnrS gene was detected in one Escherichia coli strain with a high level of ciprofloxacin resistance. Our results demonstrate the increase in occurrence of multiresistant E. coli strains with a high level of chromosomal and plasmid resistance to fluoroquinolones.     

Neisseria gonorrhoeae acquires mutations in analogous regions of gyrA and parC in fluoroquinolone-resistant isolates

Neisseria gonorrhoeae homologues of gyrA and parC have been identified using hybridization probes generated from conserved regions of diverse gyrA genes. These genes have been tentatively identified as gyrA and parC, based on predicted amino acid sequence homologies to known GyrA homologues from numerous bacterial species and to ParC from Escherichia coli and Salmonella typhimurium. The gyrA gene maps to a physical location distant from the gyrB locus on the gonococcal chromosome, which is similar to the situation found in E. coli. The parC gene is not closely linked (i.e. greater than 9 kb) to an identifiable parE gene in N. gonorrhoeae. The gonococcal GyrA is slightly larger than its E. coli homologue and contains several small insertions near the O-terminus of the predicted open reading frame. A series of ciprofloxacin-resistant mutants were selected by passage of N. gonorrhoeae on increasing concentrations of the antibiotic. Sequential passage resulted in the selection of isolates with minimum inhibitory concentrations approximately 10000-fold higher than the parental strain. Mutations within gyrA resulted in low to moderate levels of resistance, while strains with high-level resistance acquired analogous mutations in both gyrA and parC. Resistance mutations were readily transferred between N. gonorrhoeae strains by transformation. The frequencies of transformation, resulting in different levels of ciprofloxacin resistance, further support the notion that both gyrA and parC genes are invoived in the establishment of extreme levels of ciprofloxacin resistance.     

Analysis of the DNA gyrase genes ofAcholeplasma laidlawii PG-8B

A 5-kb region of theAcholeplasma laidlawii PG-8B genome was sequenced. The region contained the genes for RecF, DNA gyrase subunits A and B (GyrA and GyrB), and a fragment of the ATP-binding subunit of the hypothetical ABC transporter. In phylogenetic analysis,A. laidlawii GyrA and GyrB formed statistically significant, stable clusters with the corresponding proteins ofClostridium acetobutylicum, Staphylococcus aureus, Bacillus subtilis, andStreptococcus pneumoniae. A laidlawii PG-8B clones resistant to fluoroquinolone (FQ) antibiotic ciprofloxacin (Cff) were obtained on a selective medium. The clones carried mutations in the quinolone resistance-determining region (QRDR) ofgyrA, which resulted in substitutions Ser83→Ala, Ser83→Phe, or Asp91→Asn. No mutations were found ingyrB QRDR of the resistant clones.     

Implications of Amino Acid Substitutions in GyrA at Position 83 in Terms of Oxolinic Acid Resistance in Field Isolates of Burkholderia glumae, a Causal Agent of Bacterial Seedling Rot and Grain Rot of Rice

Oxolinic acid (OA), a quinolone, inhibits the activity of DNA gyrase composed of GyrA and GyrB and shows antibacterial activity against Burkholderia glumae. Since B. glumae causes bacterial seedling rot and grain rot of rice, both of which are devastating diseases, the emergence of OA-resistant bacteria has important implications on rice cultivation in Japan. Based on the MIC of OA, 35 B. glumae field isolates isolated from rice seedlings grown from OA-treated seeds in Japan were divided into sensitive isolates (OSs; 0.5 μg/ml), moderately resistant isolates (MRs; 50 μg/ml), and highly resistant isolates (HRs; ≥100 μg/ml). Recombination with gyrA of an OS, Pg-10, led MRs and HRs to become OA susceptible, suggesting that gyrA mutations are involved in the OA resistance of field isolates. The amino acid at position 83 in the GyrA of all OSs was Ser, but in all MRs and HRs it was Arg and Ile, respectively. Ser83Arg and Ser83Ile substitutions in the GyrA of an OS, Pg-10, resulted in moderate and high OA resistance, respectively. Moreover, Arg83Ser and Ile83Ser substitutions in the GyrA of MRs and HRs, respectively, resulted in susceptibility to OA. These results suggest that Ser83Arg and Ser83Ile substitutions in GyrA are commonly responsible for resistance to OA in B. glumae field isolates.     

New Escherichia coli gyrA and gyrB mutations which have a graded effect on DNA supercoiling

Summary We isolated new gyrA and gyrB mutations in Escherichia coli which have a graded effect on DNA supercoiling. The mutants, selected respectively for resistance to nalidixic acid and coumermycin, were sorted by means of a rapid in vivo assay of DNA gyrase activity (Aleixandre and Blanco 1987). Cells carrying a gyrB (Cou^r) mutation usually showed a decrease in DNA supercoiling, which would indicate a reduction in gyrase activity. In contrast, most of the gyrA (Nal^r) mutations had no significant effect on DNA supercoiling. Moreover, they conferred a high level of resistance to nalidixic acid and other quinolones, thus being similar to the gyrA(Nal^r) mutants currently used. We also detected rare gyrA mutants showing a reduction in DNA gyrase activity. These mutants were, in addition, resistant to only low concentrations of quinolones, which allowed us to use the phenotype of partial quinolone resistance as an indicator to score gyrA mutations affecting DNA supercoiling. When gyrB mutations were introduced into the gyrA mutants, these became more sensitive to quinolones and a decrease in supercoiling was observed. Moreover, the topA10 mutation sensitized gyrA(Nal^r) cells to quinolones. We conclude therefore that the GyrA-dependent quinolone resistance is diminished as a consequence of the reduction either in topoisomerase I or gyrase activities.     

Gemifloxacin can partially overcome quinolone resistance of H. pylori with gyrA mutation in Taiwan

Backgrounds: The levofloxacin resistance caused by gyrA gene mutation is rising rapidly to limit wide application for Helicobacter pylori eradication. We investigated whether gemifloxacin has a superior antimicrobial activity to levofloxacin against H. pylori. Materials and Methods: Forty‐four consecutive clinical H. pylori isolates with levofloxacin resistance and 80 randomly selected levofloxacin‐sensitive controls were tested for gemifloxacin sensitivity by E‐test. The resistance to levofloxacin or gemifloxacin was defined as minimal inhibitory concentration (MIC) >1 mg/L. The clinical features and GyrA mutation patterns checked by direct sequencing were also analyzed to assess its association with the H. pylori gemifloxacin resistance. Results: All levofloxacin‐sensitive H. pylori isolates were sensitive to gemifloxacin. Eight strains (18.2%) resistant to levofloxacin could be still sensitive to gemifloxacin. Gemifloxacin achieved a 5‐time lower in MIC levels against levofloxacin‐resistant isolates. Nearly all levofloxacin‐resistant isolates (97.7%, 43/44) had GyrA mutation at amino acid position 87 or 91. Double mutation sites may play dual roles in quinolone resistance, as N87K plus H57Y or D91N plus V77A mutations showed high‐level resistance to both quinolones; whereas D91Y plus A97V or D91N plus A97V mutations showed low level levofloxacin resistance to become sensitive to gemifloxacin. In H. pylori isolates with single N87K, D91Y or D91N mutation, near 20% was gemifloxacin‐sensitive and levofloxacin‐resistant. The gemifloxacin‐resistant rate of H. pylori was higher in patients with gastric ulcer than in those without (p <.05). Conclusion: Gemifloxacin is superior to levofloxacin in antimicrobial activity against clinical H. pylori isolates, and even overcome some levofloxacin resistance.     

Mutations in the gyrA and parC genes associated with fluoroquinolone resistance in clinical isolates of Citrobacter freundii

We determined partial sequences of the gyrA and parC genes of Citrobacter freundii type strain, and then examined 38 C. freundii clinical strains isolated from patients with urinary tract infections for the association of alterations in GyrA and ParC with susceptibility to fluoroquinolones. Our results suggest that in C. freundii DNA gyrase may be a primary target of quinolones, that an amino acid change at Thr-83 or Asp-87 in GyrA is sufficient to decrease susceptibility to fluoroquinolones, and that accumulation of changes in GyrA with the simultaneous presence of an alteration at Ser-80 or Glu-84 in ParC may be associated with the development of high-level fluoroquinolone resistance in C. freundii clinical isolates.     

Mutations of Helicobacter pylori associated with fluoroquinolone resistance in Korea

Background and Aim: Fluoroquinolone resistance of Helicobacter pylori is known to be dependent on mutations in the QRDR of gyrA. This study was performed to investigate the distribution of gyrA point mutations and to evaluate the impact of the mutations on second‐line H. pylori eradication therapy. Methods: After H. pylori isolation from gastric mucosal specimens, fluoroquinolone resistance was examined using the agar dilution method. DNA sequencing of the QRDR of gyrA was performed in 89 fluoroquinolone‐resistant and 27 fluoroquinolone‐susceptible isolates. Transformation experiments were performed to confirm mutations in the resistant strains. The eradication rates of moxifloxacin‐containing triple therapy were evaluated depending on the resistance of fluoroquinolone. Results: The gyrA mutations were detected in 75.3% (55 of 73 strains) of the primary resistant strains and 100% (16 strains) of the secondary resistant strains. The most common mutations were Asp‐91 (36.0%) and Asn‐87 (33.7%). The MIC values in the transformed strains differed depending on the gyrA mutations, N87, and D91. Six patients with fluoroquinolone‐resistant strains received moxifloxacin‐containing triple therapy as the second‐line therapy, and two of three patients with Asn‐87 mutations (66.7%) failed in the eradication. By contrast, three patients with Asp‐91 mutations had successful eradication treatment. Conclusions: Fluoroquinolone resistance of H. pylori was caused by gyrA Asn‐87 and Asp‐91 point mutations. The Asn‐87 mutation seems to be an important determinant of failure of fluoroquinolone‐containing triple eradication therapy based on eradication results.     

Molecular cloning of the DNA gyrase genes from Methylovorus sp. strain SS1 and the mechanism of intrinsic quinolone resistance in methylotrophic bacteria

The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The Ser83 to Thr substitution in Methylovorus sp. strain SS1, and the Ser83 to Leu and Asp87 to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.     

Quinolone resistance in absence of selective pressure: the experience of a very remote community in the Amazon forest

Background

Quinolones are potent broad-spectrum bactericidal agents increasingly employed also in resource-limited countries. Resistance to quinolones is an increasing problem, known to be strongly associated with quinolone exposure. We report on the emergence of quinolone resistance in a very remote community in the Amazon forest, where quinolones have never been used and quinolone resistance was absent in 2002.

Methods

The community exhibited a considerable level of geographical isolation, limited contact with the exterior and minimal antibiotic use (not including quinolones). In December 2009, fecal carriage of antibiotic resistant Escherichia coli was investigated in 120 of the 140 inhabitants, and in 48 animals reared in the community. All fluoroquinolone-resistant isolates were genotyped and characterized for the mechanisms of plasmid- and chromosomal-mediated quinolone resistance.

Principal Findings

Despite the characteristics of the community remained substantially unchanged during the period 2002–2009, carriage of quinolone-resistant E. coli was found to be common in 2009 both in humans (45% nalidixic acid, 14% ciprofloxacin) and animals (54% nalidixic acid, 23% ciprofloxacin). Ciprofloxacin-resistant isolates of human and animal origin showed multidrug resistance phenotypes, a high level of genetic heterogeneity, and a combination of GyrA (Ser83Leu and Asp87Asn) and ParC (Ser80Ile) substitutions commonly observed in fluoroquinolone-resistant clinical isolates of E. coli.

Conclusions

Remoteness and absence of antibiotic selective pressure did not protect the community from the remarkable emergence of quinolone resistance in E. coli. Introduction of the resistant strains from antibiotic-exposed settings is the most likely source, while persistence and dissemination in the absence of quinolone exposure is likely mostly related with poor sanitation. Interventions aimed at reducing the spreading of resistant isolates (by improving sanitation and water/food safety) are urgently needed to preserve the efficacy of quinolones in resource-limited countries, as control strategies based only on antibiotic restriction policies are unlikely to succeed in those settings.