High Efficacy of Finafloxacin on Helicobacter pylori Isolates at pH 5.0 Compared with That of Other Fluoroquinolones

ABSTRACTFinafloxacin is a novel fluoroquinolone with improved antimicrobial efficacy, especially in an acidic environment. The efficacy of finafloxacin for the inhibition ofHelicobacter pyloriinfection was compared with the efficacies of levofloxacin and moxifloxacin at neutral and acidic pH. The impacts ofgyrApoint mutation on the efficacy of those three fluoroquinolones were also investigated. A total of 128 clinicalH. pyloristrains were utilized. MICs of levofloxacin, moxifloxacin, and finafloxacin were determined at pH 5.0 and pH 7.0 by the agar dilution method. The impact ofgyrApoint mutations that are responsible for fluoroquinolone resistance was analyzed; the results showed 50 strains with an Asn-87 point mutation, 48 strains with an Asp-91 point mutation, and the remaining 30 strains with nogyrAmutations. The use of finafloxacin led to MIC values at pH 5.0 that were lower than the values seen at pH 7.0 for 112 strains (112/128, 87.5%), and this proportion was higher than that seen with moxifloxacin (21/128, 16.4%,P< 0.001). Finafloxacin also demonstrated a rate of susceptibility (MIC, <1 μg/ml) (37.5%, 48/128) at pH 5.0 that was higher than that seen with moxifloxacin (2.3%, 3/128) (P< 0.001). The trends were similar regardless of which of the Asn-87, Asp-91, and A2143 point mutations were present. In conclusion, the superior antimicrobial efficacy of finafloxacin againstH. pyloriin an acidic environment suggests the possible use of finafloxacin for treatment ofH. pyloriinfection, as has been proposed by its developer, Merlion Pharma.

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Antimicrobial Susceptibility Testing ofHelicobacter pylori in a Large Multicenter Trial: the MACH 2 Study

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.43.11.2747 ◽

1999 ◽

Vol 43 (11) ◽

pp. 2747-2752 ◽

Cited By ~ 162

Author(s):

Francis Mégraud ◽

Norbert Lehn ◽

Tore Lind ◽

Ekkehard Bayerdörffer ◽

Colm O’Morain ◽

...

Keyword(s):

Susceptibility Testing ◽

Point Mutations ◽

Multicenter Trial ◽

Dilution Method ◽

Agar Dilution Method ◽

Secondary Resistance ◽

Agar Dilution ◽

Resistant Strains ◽

H Pylori ◽

The Impact

ABSTRACT Culture and susceptibility testing of Helicobacter pylori strains was performed in a large multinational, multicenter randomized clinical trial. Culture was carried out on gastric biopsy samples obtained from 516 patients at entry and had a sensitivity of 99% when the [13C]urea breath test was used as a reference. Susceptibility testing was performed for clarithromycin and metronidazole on 485 strains by an agar dilution method and the epsilometer test (Etest) and for amoxicillin by an agar dilution method only. Resistance to clarithromycin (>1 μg/ml) was found in 3% of the H. pylori strains, with a perfect correlation between Etest and agar dilution methods. Resistance to metronidazole (>8 μl/ml) was found in 27% of the strains by agar dilution, but there were important discrepancies between it and the Etest method. No resistance to amoxicillin was found. The logarithms of the MICs of the three antibiotics against susceptible strains had a distribution close to normal. The impact of resistance was tested in the four arms of the trial. There were not enough clarithromycin-resistant strains to evaluate the impact of resistance on the cure rate of clarithromycin-based regimens. For metronidazole-resistant strains, the impact noted in the clarithromycin-metronidazole arm was partially overcome when omeprazole was added (76% eradication for resistant strains versus 95% for susceptible strains). Secondary resistance to clarithromycin occurred in strains from 12 of 105 patients (11.4%) after the failure of a clarithromycin-based regimen to effect eradication. The detection of point mutations in clarithromycin-resistant strains was performed by a combination of PCR and restriction fragment length polymorphism. Mutations (A2142G and 2143G) were found in all strains tested except one. This study stresses the importance of performing susceptibility tests in clinical trials in order to explain the results of different treatments.

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Detection of Clarithromycin-Resistant Helicobacter pylori Strains by a Preferential Homoduplex Formation Assay

Journal of Clinical Microbiology ◽

10.1128/jcm.38.1.210-214.2000 ◽

2000 ◽

Vol 38 (1) ◽

pp. 210-214

Author(s):

Shin Maeda ◽

Haruhiko Yoshida ◽

Hironari Matsunaga ◽

Keiji Ogura ◽

Osamu Kawamata ◽

...

Keyword(s):

Helicobacter Pylori ◽

Point Mutations ◽

23S Rrna ◽

Dilution Method ◽

Agar Dilution Method ◽

Wild Type ◽

Urease Test ◽

Agar Dilution ◽

Type Gene ◽

H Pylori

ABSTRACT It has been shown that resistance to clarithromycin, a major cause of failure in Helicobacter pylori eradication therapy, is associated with point mutations in the 23S rRNA gene. We sought to apply the preferential homoduplex formation assay (PHFA), a novel technique for the efficient detection of point mutations, to detection of the mutations. PHFA was performed on streptavidin-coated microtiter plates with biotin- and dinitrophenyl-labeled amplicons to detect the wild-type gene or each mutant gene. DNA samples were extracted from gastric juice specimens of 412 patients with H. pylori infection and were applied to the assay. The detection threshold of PHFA was as few as 10 gene copies. The sensitivity of PHFA for the detection of H. pylori infection was higher than those of culture and the rapid urease test. A total of 337 (81.8%) samples had the wild-type gene, 38 (9.2%) had the A2144G mutation, and 37 (9.0%) contained both the wild type and a mutation (A2144G in 30 samples, A2143G in 5 samples, and A2143G plus A2144G in 2 samples). About half the strains isolated from patients with mixed infection were susceptible by the agar dilution method (MIC, <0.1 mg/liter). Therefore, PHFA can detect clarithromycin-resistant H. pylori strains, even in patients with mixed infections with the wild type, that are not detectable by the agar dilution method.

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Helicobacter pylori Eradication According to Sequencing-Based 23S Ribosomal RNA Point Mutation Associated with Clarithromycin Resistance

Journal of Clinical Medicine ◽

10.3390/jcm9010054 ◽

2019 ◽

Vol 9 (1) ◽

pp. 54 ◽

Cited By ~ 2

Author(s):

Seung In Seo ◽

Byoung Joo Do ◽

Jin Gu Kang ◽

Hyoung Su Kim ◽

Myoung Kuk Jang ◽

...

Keyword(s):

Helicobacter Pylori ◽

Point Mutation ◽

Ribosomal Rna ◽

Eradication Rate ◽

Point Mutations ◽

Clarithromycin Resistance ◽

Clinically Significant ◽

H Pylori ◽

23S Ribosomal Rna ◽

Significant Point

Background/Aims: Clarithromycin resistance in Helicobacter pylori is associated with point mutations in the 23S ribosomal RNA (rRNA) gene. We investigated the point mutations in the 23S rRNA genes of patients with clarithromycin-resistant H. pylori and compared the H. pylori eradication rates based on the point mutations. Methods: A total of 431 adult patients with H. pylori infection were recruited in Kangdong Sacred Heart Hospital in 2017 and 2018. Patients who did not have point mutations related to clarithromycin resistance and/or had clinically insignificant point mutations were treated with PAC (proton pump inhibitor, amoxicillin, clarithromycin) for seven days, while patients with clinically significant point mutations were treated with PAM (proton pump inhibitor, amoxicillin, metronidazole) for seven days. H. pylori eradication rates were compared. Results: Sequencing-based detection of point mutations identified four mutations that were considered clinically significant (A2142G, A2142C, A2143G, A2143C). The clarithromycin resistance rate was 21.3% in the overall group of patients. A2143G was the most clinically significant point mutation (84/431, 19.5%), while T2182C was the most clinically insignificant point mutation (283/431, 65.7%). The overall H. pylori eradication rate was 83.7%, and the seven-day PAM-treated clarithromycin-resistance group showed a significantly lower eradication rate than the seven-day PAC-treated nonresistance group (ITT; 55.4% (51/92) vs. 74.3% (252/339), p = 0.001, PP; 66.2% (51/77) vs. 88.4% (252/285), p = 0.0001). Conclusions: There were significantly lower eradication rates in the patients with clarithromycin-resistant H. pylori when treated with PAM for seven days. A future study comparing treatment regimens in clarithromycin-resistant H. pylori-infected patients may be necessary.

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Potential of FTIR-Spectroscopy for Drugs Screening against Helicobacter pylori

Antibiotics ◽

10.3390/antibiotics9120897 ◽

2020 ◽

Vol 9 (12) ◽

pp. 897

Author(s):

Pedro Sousa Sampaio ◽

Cecília R. C. Calado

Keyword(s):

Helicobacter Pylori ◽

Ftir Spectroscopy ◽

Partial Least Square ◽

Least Square ◽

New Drugs ◽

Partial Least Square Regression ◽

Dilution Method ◽

Agar Dilution Method ◽

Molecular Fingerprint ◽

H Pylori

Helicobacter pylori colonizes the human stomach of half of the world’s population. The infection if not treated, persists through life, leading to chronic gastric inflammation, that may progress to severe diseases as peptic ulcer, gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. The first line of treatment, based on 7 to 21 days of two antibiotics associated with a proton pump inhibitor, is, however, already failing most due to patient non-compliance that leads to antibiotic resistance. It is, therefore, urgent to screen for new and more efficient antimicrobials against this bacterium. In this work, Fourier Transform Infrared (FTIR) spectroscopy was evaluated to screen new drugs against H. pylori, in rapid (between 1 to 6 h), and high-throughput mode and based on a microliter volume processes in relation to the agar dilution method. The reference H. pylori strains 26,695 and J99, were evaluated against a peptide-based antimicrobial and the clinical antibiotic clarithromycin, respectively. After optimization of the assay conditions, as the composition of the incubation mixture, the time of incubation, and spectral pre-processing, it was possible to reproducibly observe the effect of the drug on the bacterial molecular fingerprint as pointed by the spectra principal component analysis. The spectra, obtained from both reference strains, after its incubation with drugs concentrations lower than the MIC, presented peak ratios statistically different (p < 0.05) in relation to the bacteria incubated with drugs concentrations equal or higher to the MIC. It was possible to develop a partial least square regression model, enabling to predict from spectra of both bacteria strains, the drug concentration on the assay, with a high correlation coefficient between predicted and experimental data (0.91) and root square error of 40% of the minimum inhibitory concentration. All this points to the high potential of the technique for drug screening against this fastidious growth bacterium.

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Cholesterol Enhances Helicobacter pylori Resistance to Antibiotics and LL-37

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00016-11 ◽

2011 ◽

Vol 55 (6) ◽

pp. 2897-2904 ◽

Cited By ~ 63

Author(s):

David J. McGee ◽

Alika E. George ◽

Elizabeth A. Trainor ◽

Katherine E. Horton ◽

Ellen Hildebrandt ◽

...

Keyword(s):

Helicobacter Pylori ◽

Lipid A ◽

Polymyxin B ◽

Defined Medium ◽

Vital Role ◽

Content Type ◽

The Two Cultures ◽

H Pylori ◽

The Impact

ABSTRACTThe human gastric pathogenHelicobacter pyloristeals host cholesterol, modifies it by glycosylation, and incorporates the glycosylated cholesterol onto its surface via a cholesterol glucosyltransferase, encoded bycgt. The impact of cholesterol onH. pyloriantimicrobial resistance is unknown.H. pyloristrain 26695 was cultured in Ham's F12 chemically defined medium in the presence or absence of cholesterol. The two cultures were subjected to overnight incubations with serial 2-fold dilutions of 12 antibiotics, six antifungals, and seven antimicrobial peptides (including LL-37 cathelicidin and human alpha and beta defensins). Of 25 agents tested, cholesterol-grownH. pyloricells were substantially more resistant (over 100-fold) to nine agents than wereH. pyloricells grown without cholesterol. These nine agents included eight antibiotics and LL-37.H. pyloriwas susceptible to the antifungal drug pimaricin regardless of cholesterol presence in the culture medium. Acgtmutant retained cholesterol-dependent resistance to most antimicrobials but displayed increased susceptibility to colistin, suggesting an involvement of lipid A. Mutation oflpxE, encoding lipid A1-phosphatase, led to loss of cholesterol-dependent resistance to polymyxin B and colistin but not other antimicrobials tested. Thecgtmutant was severely attenuated in gerbils, indicating that glycosylation is essentialin vivo. These findings suggest that cholesterol plays a vital role in virulence and contributes to the intrinsic antibiotic resistance ofH. pylori.

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Antimicrobial Sensitivity Pattern of Helicobacter pylori Isolates among Subgroup of Bangladeshi Patients

Faridpur Medical College Journal ◽

10.3329/fmcj.v8i2.20280 ◽

2014 ◽

Vol 8 (2) ◽

pp. 49-52

Author(s):

MMSU Islam ◽

Shamsun Nahar ◽

Mst Naznin Sarker ◽

ASM Salimullah ◽

Mohammad Asadur Rahman ◽

...

Keyword(s):

Helicobacter Pylori ◽

Diarrhoeal Disease ◽

Cross Sectional Study ◽

Dilution Method ◽

Agar Dilution Method ◽

Cross Sectional ◽

Antimicrobial Sensitivity ◽

Sensitivity Pattern ◽

H Pylori ◽

Medical University

This cross sectional study was carried out at Bangabandhu Sheikh Mujib Medical University (BSMMU) and International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) from July 2008 to September 2009. Aim of the study was to find out the antimicrobial susceptibility profile of Helicobacter pylori isolates from dyspeptic patients. Total 224 dyspeptic patients from Out Patient Department (OPD) of BSMMU were initially enrolled after informed written consent. After upper GI endoscopy 157 patients were finally included who had erosions, ulcers or atrophic changes in the stomach or duodenum. Two biopsy samples were taken from each of them. Samples were incubated at 37°C in a double gas incubator with 5%O2, 10%CO2 and 85%N2. Total 82 (52.23%) samples were found positive for H. pylori. Isolated organisms were then tested for sensitivity to Amoxicillin, Clarithromycin, Tetracycline, Levofloxacin and Metronidazole by Agar dilution method. Among 82 patients 51(62.2%) were male and 31(37.8) were female with a male:female ratio 1.6:1. Patients were categorized into two groups one having gastric or duodenal ulcer (30.5%) and other having no ulcer (69.5%). Among these isolates 92.7% were sensitive to Amoxicillin, 89% to Clarithromycin, 81.7% to Tetracycline, 80.5% to Levofloxacin and only 26.8% to Metronidazole. Beside these, 81.7% isolates were sensitive to both Amoxicillin and Clarithromycin, 74.4% to Amoxicillin and Tetracycline, 73.2% to Amoxicillin and Levofloxacin, 72% to Clarithromycin and Tetracycline, 59% to Clarithromycin and Levofloxacin and 51% to Tetracycline and Levofloxacin DOI: http://dx.doi.org/10.3329/fmcj.v8i2.20280 Faridpur Med. Coll. J. 2013;8(2): 49-52

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Helicobacter pylori antibiotic susceptibility patterns in Bangladesh: Emerging levofloxacin resistance

The Journal of Infection in Developing Countries ◽

10.3855/jidc.7713 ◽

2016 ◽

Vol 10 (03) ◽

pp. 245-253 ◽

Cited By ~ 13

Author(s):

Hafeza Aftab ◽

Muhammad Miftahussurur ◽

Phawinee Subsomwong ◽

Faruque Ahmed ◽

AK Azad Khan ◽

...

Keyword(s):

Helicobacter Pylori ◽

Triple Therapy ◽

Antibiotic Susceptibility ◽

Resistance Rate ◽

Resistance Pattern ◽

Dilution Method ◽

Agar Dilution Method ◽

Peptic Ulcers ◽

H Pylori ◽

Resistance Rates

Introduction: The most recent study to report Helicobacter pylori antibiotic resistance rates in Bangladesh was published 15 years ago and did not include levofloxacin. We therefore aimed to determine the current antibiotic susceptibility of H. pylori to amoxicillin, clarithromycin, metronidazole, tetracycline and levofloxacin in Bangladesh. Methodology: This study included 133 consecutive patients who underwent endoscopy examination at Dhaka Medical College in November 2014. The serial two-fold agar dilution method was used to determine the minimum inhibitory concentrations of the five antibiotics. Results: Among 56 cultured strains, H. pylori showed high rates of resistance to clarithromycin and metronidazole (39.3% and 94.6%, respectively). Moreover, levofloxacin showed an emerging antimicrobial resistance pattern (66.1%), which was higher in patients with gastritis than that in those with peptic ulcers (p = 0.02). The resistance rate of levofloxacin was significantly higher in patients living in Dhaka city compared to those living in the village (p = 0.049). However, amoxicillin and tetracycline resistance rates were very low. Resistance to both metronidazole and levofloxacin was most commonly observed. Conclusions: The rates of resistance to clarithromycin, metronidazole, and levofloxacin were high in Bangladesh, which suggests that triple therapy based on these drugs may not be useful as first-line therapies in Bangladesh. Alternative strategies such as furazolidone-based triple therapy, bismuth-based quadruple therapies, or sequential therapy may be more effective for patients in in Bangladesh.

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High Prevalence of Antibiotic Resistance in Iranian Helicobacter pylori Isolates: Importance of Functional and Mutational Analysis of Resistance Genes and Virulence Genotyping

Journal of Clinical Medicine ◽

10.3390/jcm8112004 ◽

2019 ◽

Vol 8 (11) ◽

pp. 2004 ◽

Cited By ~ 8

Author(s):

Nastaran Farzi ◽

Abbas Yadegar ◽

Amir Sadeghi ◽

Hamid Asadzadeh Aghdaei ◽

Sinéad Marian Smith ◽

...

Keyword(s):

Helicobacter Pylori ◽

Antibiotic Resistance ◽

Rrna Genes ◽

23S Rrna ◽

Dilution Method ◽

Agar Dilution Method ◽

Gyra Gene ◽

Therapeutic Regime ◽

High Prevalence ◽

H Pylori

The high prevalence of antibiotic resistance in Helicobacter pylori has become a great challenge in Iran. The genetic mutations that contribute to the resistance have yet to be precisely identified. This study aimed to investigate the prevalence of antibiotic resistance and virulence markers in Iranian H. pylori isolates and to analyze if there is any association between resistance and genotype. Antibiotic susceptibility patterns of 68 H. pylori isolates were investigated against metronidazole, clarithromycin, amoxicillin, rifampicin, ciprofloxacin, levofloxacin, and tetracycline by the agar dilution method. The frxA, rdxA, gyrA, gyrB, and 23S rRNA genes of the isolates were sequenced. The virulence genotypes were also determined using PCR. Metronidazole resistance was present in 82.4% of the isolates, followed by clarithromycin (33.8%), ciprofloxacin (33.8%), rifampicin (32.4%), amoxicillin (30.9%), levofloxacin (27.9%), and tetracycline (4.4%). Overall, 75% of the isolates were resistant to at least two antibiotics tested and considered as a multidrug resistance (MDR) phenotype. Most of the metronidazole-resistant isolates carried frameshift mutations in both frxA and rdxA genes, and premature termination occurred in positions Q5Stop and Q50Stop, respectively. Amino acid substitutions M191I, G208E, and V199A were predominantly found in gyrA gene of fluoroquinolone-resistant isolates. A2143G and C2195T mutations of 23S rRNA were found in four clarithromycin-resistant isolates. Interestingly, significant associations were found between resistance to metronidazole (MNZ) and cagA-, sabA-, and dupA-positive genotypes, with p = 0.0002, p = 0.0001, and p = 0.0001, respectively. Furthermore, a significant association was found between oipA “on” status and resistance to amoxicillin (AMX) (p = 0.02). The prevalence of H. pylori antibiotic resistance is high in our region, particularly that of metronidazole, clarithromycin, ciprofloxacin, and MDR. Simultaneous screening of virulence and resistance genotypes can help clinicians to choose the appropriate therapeutic regime against H. pylori infection.

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Activity of Bulgarian propolis against 94 Helicobacter pylori strains in vitro by agar-well diffusion, agar dilution and disc diffusion methods

Journal of Medical Microbiology ◽

10.1099/jmm.0.45880-0 ◽

2005 ◽

Vol 54 (5) ◽

pp. 481-483 ◽

Cited By ~ 83

Author(s):

Lyudmila Boyanova ◽

Galina Gergova ◽

Rossen Nikolov ◽

Sirigan Derejian ◽

Elena Lazarova ◽

...

Keyword(s):

Helicobacter Pylori ◽

Growth Inhibition ◽

Biological Effects ◽

Diffusion Method ◽

Dilution Method ◽

Agar Dilution Method ◽

Propolis Extract ◽

Agar Dilution ◽

H Pylori

Propolis exhibits antimicrobial, anti-inflammatory and other biological effects. The aim of this study was to evaluate the activity of 30 % ethanolic extract of Bulgarian propolis against 94 Helicobacter pylori strains by three methods. By the agar-well diffusion method, only 13.8 % of the strains exhibited no inhibition by 30 μl propolis extract (containing 9 mg propolis) and all isolates were inhibited to some extent by 90 μl of the extract (27 mg propolis) per well. The mean diameters of growth inhibition by 30, 60 or 90 μl propolis extract or 30 μl 96 % ethanol per well were 16.8, 19.2, 27.5 and 8.3 mm, respectively. The propolis extract was more active than the ethanol (P < 0.001). With 90 μl propolis extract per well, 69.4 % of the strains exhibited large diameters of growth inhibition (⩾20 mm) versus 26.6 % with 30 μl per well (P < 0.001). With moist propolis discs, inhibition was detected in more strains (92.1 %) than with dried discs (78.2 %, P < 0.05), with mean inhibitory diameters of 18.7 and 13.8 mm, respectively. By the agar dilution method, 100 and 300 μg propolis ml−1 inhibited the growth of 57.1 % and 76.2 %, respectively, of the 21 strains tested. In conclusion, Bulgarian propolis had a strong and dose-dependent activity against most of the H. pylori strains tested. Although the effect of propolis on H. pylori in vitro is promising, further microbiological, pharmacological and clinical trials are required.

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The Bifunctional Enzyme SpoT Is Involved in the Clarithromycin Tolerance of Helicobacter pylori by Upregulating the Transporters HP0939, HP1017, HP0497, and HP0471

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02011-16 ◽

2017 ◽

Vol 61 (5) ◽

Cited By ~ 6

Author(s):

Xiwen Geng ◽

Wen Li ◽

Zhenghong Chen ◽

Sizhe Gao ◽

Wei Hong ◽

...

Keyword(s):

Helicobacter Pylori ◽

Point Mutations ◽

23S Rrna ◽

Bifunctional Enzyme ◽

Key Factors ◽

Content Type ◽

Bacterial Drug Resistance ◽

Resistant Strains ◽

H Pylori

ABSTRACT Clarithromycin (CLA) is a commonly recommended drug for Helicobacter pylori eradication. However, the prevalence of CLA-resistant H. pylori is increasing. Although point mutations in the 23S rRNA are key factors for CLA resistance, other factors, including efflux pumps and regulation genes, are also involved in the resistance of H. pylori to CLA. Guanosine 3′-diphosphate 5′-triphosphate and guanosine 3′,5′-bispyrophosphate [(p)ppGpp)], which are synthesized by the bifunctional enzyme SpoT in H. pylori, play an important role for some bacteria to adapt to antibiotic pressure. Nevertheless, no related research involving H. pylori has been reported. In addition, transporters have been found to be related to bacterial drug resistance. Therefore, this study investigated the function of SpoT in H. pylori resistance to CLA by examining the shifts in the expression of transporters and explored the role of transporters in the CLA resistance of H. pylori. A ΔspoT strain was constructed in this study, and it was shown that SpoT is involved in H. pylori tolerance of CLA by upregulating the transporters HP0939, HP1017, HP0497, and HP0471. This was assessed using a series of molecular and biochemical experiments and a cDNA microarray. Additionally, the knockout of genes hp0939, hp0471, and hp0497 in the resistant strains caused a reduction or loss (the latter in the Δhp0497 strain) of resistance to CLA. Furthermore, the average expression levels of these four transporters in clinical CLA-resistant strains were considerably higher than those in clinical CLA-sensitive strains. Taken together, our results revealed a novel molecular mechanism of H. pylori adaption to CLA stress.

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