Levofloxacin-Resistant Helicobacter pylori in Hong Kong (original) (raw)
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Increased resistance of Helicobacter pylori to clarithromycin and metronidazole has resulted in recommendation to substitute fluoroquinolones for eradication therapy. The aims of the study were to determine the prevalence and changes in primary levofloxacin resistance related to H. pylori gyrA sequences. The study utilized H. pylori strains isolated from patients undergoing gastroscopy in Bogotá, Colombia from 2009 to 2014. Levofloxacin susceptibility was assessed by agar dilution. Mutations in gyrA sequences affecting the quinolone resistance-determining region (QRDR) were evaluated by direct sequencing. Overall, the mean prevalence of primary levofloxacin resistance was 18.2% (80 of 439 samples). Resistance increased from 11.8% (12/102) in 2009 to 27.3% (21/77) in 2014 (p = 0.001). gyrA mutations in levofloxacin resistant strains were present in QRDR positions 87 and 91. The most common mutation was N87I (43.8%, 35/80) followed by D91N (28.8%, 23/80) and N87K (11.3%, 9/80). Levofloxacin resistance increased markedly in Colombia during the six-year study period. Primary levofloxacin resistance was most often mediated by point mutations in gyrA, with N87I being the most common QRDR mutation related to levofloxacin resistance.
Asia-pacific Journal of Molecular Biology and Biotechnology, 2022
Clarithromycin (CLA) and levofloxacin (LFX) have been recommended as the most effective antibiotics for treating Helicobacter pylori infection. However, the increase in H. pylori's resistance to antibiotics is an alarming and growing challenge. The study aimed to determine the antimicrobial resistance profiles of H. pylori strains isolated from patients at the Hospital for Tropical Diseases and to detect point mutations in 23S ribosomal RNA (23S rRNA) and gyraseA (gyrA) genes. Point mutations in 23S rRNA and gyrA were detected using Sanger sequencing. Antibiotic resistance was tested by the microdilution method. Out of the 45 isolates, 44 (97.8%) were found to be resistant to at least one antibiotic, 38 (84.4%) resistant to metronidazole (MTZ), and all were sensitive to amoxicillin (AMX) and tetracycline (TET). Sixty percent of the isolated strains were resistant to 3-6 antibiotics; among them, multiple drug resistance (MDR) strains presented twenty percent resistance to more than two classes of antibiotics. Eleven strains (24.4%) carried two mutations associated with CLA and LFX but only nine of them were dual resistant to CLA and LFX, and twenty-four (53.3%) carried either CLA or LFX mutation. The point mutations A2143G in the 23S rRNA and N87K (Asn87Lys) in the gyrA were detected in the CLA and LFX resistant strains, respectively. The prevalence of MDR, especially CLA, MTZ, and LFX resistance, in the H. pylori isolates suggests that the use of these antibiotics need to be more considerable and cautious.
Gut Pathogens
Background: Due to increased prevalence of H. pylori antimicrobial resistance worldwide and more importantly the resistance patterns vary between different geographical regions, it is important to survey local H. pylori antibiotic resistance profile to provide physicians with more informed drug choices to better treat H. pylori infection. To our knowledge, this is the first study to examine the prevalence of antimicrobial resistance of H. pylori in Karnataka state of South India. Results: A total of 113 H. pylori strains were isolated from gastric biopsies and tested: 81.4% were resistant to metronidazole, 54.9% were resistant to levofloxacin, 20.4% were resistant to clarithromycin, 5.3% were resistant to tetracycline and 7.1% were resistant to amoxicillin. Multidrug resistance was detected in 59.3% of total isolated strains, among which 86.6% were resistant to at least both metronidazole and levofloxacin. In this study, 38 out of 113 H. pylori strains had been whole-genome sequenced. Based on the draft genomes, RdxA and/or FrxA inactivation mutations were found to present in 75% of metronidazole-resistant strains. Clarithromycin-resistant strains had mainly A2143G and G2224A mutations in the 23 rRNA gene. While 87.1% levofloxacin-resistant strains had amino acid substitution mutations occurring predominantly at N87 and D91 in GyrA, novel mutations in the same protein including an insertion of five amino acid residues (QDNSV), immediately after the start codon, and a substitution mutation at R295 were identified. Conclusion: High primary resistance to metronidazole and levofloxacin, and a modest occurrence of clarithromycin resistance were revealed in H. pylori strains isolated from Karnataka patients. Therefore metronidazole-, levofloxacinand clarithromycin-based triple therapies are not suitable as first-line treatment in Karnataka. Both amoxicillin and tetracycline can still be used to eradicate H. pylori infection in this region. We also revealed novel mutations in GyrA protein that possibly contribute to H. pylori resistance in levofloxacin, which merit further investigations.
Antimicrobial Agents and Chemotherapy, 2011
The accuracy of genotypic resistance to levofloxacin (gyrA mutations) and its agreement with treatment outcomes after levofloxacin-based therapy have not been reported. We aimed to assess the correlation. Helicobacter pylori strains isolated from patients who received levofloxacin-based and clarithromycin-based triple therapies in a previous randomized trial were analyzed for point mutations in gyrA and 23S rRNA. PCR followed by direct sequencing was used to assess the gyrA and 23S rRNA mutations. An agar dilution test was used to determine the MICs of clarithromycin and levofloxacin. We found that the agreement between genotypic and phenotypic resistance to levofloxacin was best when the MIC breakpoint was >1 g/ml (kappa coefficient, 0.754). The eradication rates in patients with and without gyrA mutations were 41.7% and 82.7%, respectively (P ؍ 0.003). The agreement between genotypic and phenotypic resistance to clarithromycin was best when the MIC breakpoint was >2 g/ml (kappa, 0.694). The eradication rates in patients with and without 23S rRNA mutations were 7.7% and 93.5%, respectively (P < 0.001). The agreements (kappa coefficient) between therapeutic outcomes after clarithromycin-based triple therapy and genotypic and phenotypic resistance were 0.671 and 0.356, respectively. The agreements (kappa coefficient) between therapeutic outcomes after levofloxacin-based triple therapy and genotypic and phenotypic resistance were 0.244 and 0.190, respectively. In conclusion, gyrA and 23S rRNA mutations in H. pylori strains appeared to be better markers than phenotypic resistance in the prediction of treatment outcomes. The optimal breakpoints for levofloxacin and clarithromycin resistance appeared to be >1 g/ml and >2 g/ml, respectively.
Journal of Gastroenterology and Hepatology, 2012
Background and Aim: New regimens, including those with new fluoroquinolones, have been developed to overcome the antibiotic resistance of Helicobacter pylori. We aimed to assess the antibiotic resistance rates, as well as the molecular mechanisms of fluoroquinolone resistance, of the clinical isolates obtained in Korea. Methods: The minimal inhibitory concentration (MIC) values of ciprofloxacin, amoxicillin, clarithromycin, metronidazole and tetracycline were determined by the agar dilution method for 185 treatment-naïve Helicobacter pylori isolates. The resistant strains were evaluated for the presence of point mutations in the quinolone resistancedetermining region (QRDR) of the gyrA and gyrB genes by direct nucleotide sequencing. Results: Twenty-nine (29/185, 15.7%) of the strains were found to be resistant to ciprofloxacin. The resistance rates to amoxicillin, clarithromycin, metronidazole and tetracycline were 2.2% (four of 185), 10.8% (20 of 185), 30.3% (56 of 185) and 0.5% (one of 185), respectively. The most common mutations in the H. pylori gyrA gene were found at codons corresponding to Asp87 (16/29, 55.2%) and Asn91 (10/29, 34.5%). Conclusions: Primary H. pylori resistance to ciprofloxacin occurred at a high frequency. The fluoroquinolone resistance is most likely mediated through amino acid point mutation in the gyrA gene at Asn87 and Asp91.
Bangladesh Journal of Medical Microbiology, 2019
Background: Clarithromycin and Levofloxacin are most frequently included in the standard triple therapies for H. pylori eradication in our country. Resistance to clarithromycin and fluoroquinolones are particularly related with treatment failure. Objectives: The objective of this study was to detect, clarithromycin and levofloxacin resistance associated with gene mutations in H. pylori directly from gastric biopsies using an allele specific primer-PCR (ASP-PCR) assay. Materials and Methods: Gastric biopsy specimens were collected from 143 adult dyspeptic patients, from Department of Gastroenterology, BSMMU and Dhaka Medical College Hospital (DMCH), during the period of March, 2018 to February, 2019. H. pylori was identified by rapid urease test, ureC gene by PCR, histological staining and culture. ASP-PCR was used to identify 23S rRNA gene and gyrA gene mutation predictive of clarithromycin and levofloxacin resistant H. pylori respectively. Results: H. pylori positive cases were 32....
International Journal of Antimicrobial Agents, 2014
Antimicrobial resistance in Helicobacter pylori has increased worldwide and has become a major cause of treatment failure in many countries, including Vietnam. It is advisable to perform an antibiogram to provide optimal regimens for H. pylori eradication. This study evaluated the rate of antibiotic resistance to the four commonly used antibiotics against H. pylori at a tertiary care hospital in Central Vietnam and analysed point mutations in genes related to clarithromycin (CLA) and levofloxacin (LFX) resistance. A total of 92 H. pylori strains from gastric biopsy specimens were tested; 42.4% were resistant to CLA (primary, 34.2%; secondary, 73.7%), 41.3% to LFX (primary, 35.6%; secondary, 63.2%), 76.1% to metronidazole (MTZ) and 1.1% to amoxicillin. Multidrug resistance was observed in 56.5% (primary, 50.7%; secondary, 78.9%) of isolates (P < 0.05). The rate of resistance to LFX was significantly higher in females than males (P < 0.05). Most of the CLA-and LFX-resistant strains harboured resistance-associated mutations, with common positions at A2143G and T2182C in the 23S rRNA gene and at Asn-87 or Asp-91 in GyrA. Minimum inhibitory concentrations (MICs) increased in strains carrying quadruple mutations in their 23S rRNA gene and in strains with Asn-87 GyrA mutation (P < 0.05). One high-level LFX-resistant strain (MIC = 32 mg/L) had new mutations with a combination of N87A, A88N and V65I. High resistance rates to CLA, MTZ and LFX discourage standard and LFX-based triple therapies as first-line treatment in Vietnam.
Emerging Helicobacter pylori levofloxacin resistance and novel genetic mutation in Nepal
BMC microbiology, 2016
The prevalence of Helicobacter pylori antibiotic susceptibility in the Nepalese strains is untracked. We determined the antibiotic susceptibility for H. pylori and analyzed the presence of genetic mutations associated with antibiotic resistance in Nepalese strains. This study included 146 consecutive patients who underwent gastroduodenal endoscopy in Kathmandu, Nepal. Among 42 isolated H. pylori, there was no resistance to amoxicillin and tetracycline. In contrast, similar with typical South Asian patterns; metronidazole resistance rate in Nepalese strains were extremely high (88.1 %, 37/42). Clarithromycin resistance rate in Nepalese strains were modestly high (21.4 %, 9/42). Most of metronidazole resistant strains had highly distributed rdxA and frxA mutations, but were relative coincidence without a synergistic effect to increase the minimum inhibitory concentration (MIC). Among strains with the high MIC, 63.6 % (7/11) were associated with frameshift mutation at position 18 of fr...
JPMA. The Journal of the Pakistan Medical Association, 2012
To assess fluoroquinolone and clarithromycin susceptibility pattern along with the types of genomic mutations involved in the resistance of Helicobacter pylori isolates. The cross-sectional study was conducted at the Department of Pathology and Microbiology, Aga Khan University Hospital, Karachi, from June 2009 to July 2010, and comprised 162 gastric biopsy samples which were tested with GenoTypeHelicoDR (Hain Lifescience GmbH, Germany), a reverse hybridisation multiplex polymerase chain reaction (PCR) line probe assay (LiPA). Also, 23S rRNA (ribosomal ribonucleic acid) gene was analysed with three-point mutations at A2146G, A2146C and A2147G for clarithromycin, and gyrA gene was analyzed at two codon positions 87 and 91 for fluoroquinolone susceptibility testing. SPSS 19 was used for statistical analyses. Clarithromycin resistance was seen in 60 (37.0%) of the isolates mainly involving mutation at A2147G (85%) followed by A2146G (n=35; 21.6%) and A2146C (n=19; 11.6%). Fluoroquinolo...