scholarly journals High prevalence of antibiotic resistance inHelicobacter pyloriisolates from Iran: importance of functional and mutational analysis of resistance genes and virulence genotyping

2019 ◽  
Author(s):  
Nastaran Farzi ◽  
Abbas Yadegar ◽  
Hamid Asadzadeh Aghdaei ◽  
Amir Sadeghi ◽  
Mohammad Reza Zali
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Mutational Analysis ◽  
Rrna Genes ◽  
23S Rrna ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Virulence Markers ◽  
High Prevalence ◽  
H Pylori

AbstractThe high prevalence of antibiotic resistance inHelicobacter pylorihas 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 IranianH. pyloriisolates and to analyze if there is any association between resistance and genotype. Antibiotic susceptibility patterns of 33H. pyloriisolates were investigated against metronidazole, clarithromycin, amoxicillin, rifampicin, ciprofloxacin, levofloxacin and tetracycline by the agar dilution method. ThefrxA, rdxA, gyrA, gyrBand 23S rRNA genes of the isolates were sequenced. The virulence genotypes were also determined using PCR. Metronidazole resistance was present in 81.8% of the isolates, followed by clarithromycin (36.4%), ciprofloxacin (36.4%), amoxicillin (30.3%), rifampicin (30.3%), levofloxacin (27.3%) and tetracycline (6.1%). Most of the metronidazole-resistant isolates carried frameshift mutations in bothfrxAandrdxAgenes, and premature termination was occurred in positions Q5Stop and Q50Stop, respectively. Amino acid substitutions M191I, G208E, and V199A were predominantly found ingyrAgene of fluoroquinolone-resistant isolates. A2143G and C2195T mutations of 23S rRNA were found in four isolates. Interestingly, significant associations were demonstrated between intactcagPAI and resistance to rifampicin (P= 0.027), and between susceptibility to amoxicillin andcagPAI intactness (P= 0.016). The prevalence ofH. pyloriantibiotic resistance is high in our region, particularly that of metronidazole, clarithromycin, ciprofloxacin and multidrug resistance. Occurrence of mutations in resistance genes were involved in the development of resistance, especially in less virulent isolates.

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

2019 ◽  
Vol 8 (11) ◽  
pp. 2004 ◽  
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.

scholarly journals Analysis of the primary and post-treatment antibiotic resistance of Helico-bacter pylori in Nanjing area

2020 ◽  
Vol 21 ◽  
Author(s):  
Zong-Dan Jiang ◽  
Bang-Shun He ◽  
Zhen-Yu Zhang ◽  
Shu-Kui Wang ◽  
Dan Ran ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Post Treatment ◽  
Current Status ◽  
Antibiotics Resistance ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Rapid Urease Test ◽  
Urease Test ◽  
H Pylori ◽  
Resistance Rates

Background: Resistance of Helicobacter pylori（H. pylori） to antibiotics is increasing worldwide. In order to understand the current situation of antibiotic resistance in Nanjing and provide a reasonable basis for clinical selection of antibiotics to cure H. Pylori. Objective: To investigate the current status of H. Pylori antibiotics resistance in Nanjing area, and analyze the primary and post-treatment antibiotic resistance of H. pylori in this area. Methods: During the period from July 2017 to December 2019, 1533 gastric mucosal specimens from patients with positive H. pylori confirmed by breath test or rapid urease test were collected for isolation and identify H. pylori. The agar dilution method was used for antibiotic resistance test. Results: The result showed that the resistance rates of H. pylori to amoxicillin, clarithromycin, levofloxacin, furazolidone, tetracycline and metronidazole were 2.74%, 47.03%, 33.59%, 0.91%, 0.52% and 80.76%, respectively in the period of July 2017 to December 2019. The resistance rates of H. pylori (primary Vs post-treatment) to amoxicillin, clarithromycin, levofloxacin, furazolidone, tetracycline and metronidazole were 1.83% Vs 6.08%, 38.62% Vs 77.81%, 27.41% Vs 56.23%, 0.58% Vs 2.13%, 0.33% Vs 1.22%, 78.57% Vs 88.75%, respectively. Conclusions: Antibiotic resistance of H. pylori remained a problem for the effective eradication of this pathogen and its associated diseases in Nanjing area. For post-treatment eradication patients, clinicians should took into account regional antibiotic resistance rate, personal antibiotic exposure history, economic benefit ratio, adverse antibiotic reactions, antibiotic availability and other aspects．

scholarly journals Genotypic and Phenotypic Resistance to Clarithromycin in Helicobacter pylori Strains

2020 ◽  
Vol 9 (6) ◽  
pp. 1930
Author(s):  
Eun Jeong Gong ◽  
Ji Yong Ahn ◽  
Jung Mogg Kim ◽  
Sun Mi Lee ◽  
Hee Kyong Na ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antimicrobial Resistance ◽  
Rrna Genes ◽  
23S Rrna ◽  
Dilution Method ◽  
Phenotypic Resistance ◽  
Clarithromycin Resistance ◽  
Resistant Phenotype ◽  
23S Rrna Genes ◽  
H Pylori

Background: The increasing prevalence of antimicrobial resistance, together with the lack of novel treatment options, negatively affects successful eradication of Helicobacter pylori. The aim of this study was to investigate genetic mutations in the 23S rRNA genes, which is associated with clarithromycin resistance, and to determine the clinical impact of genotype on phenotypic antimicrobial resistance. Methods: A total of 46 H. pylori strains were obtained from 13 patients, before and after unsuccessful eradication with clarithromycin-based triple therapy. The phenotypic resistance of each H. pylori strain was determined by minimum inhibitory concentration against clarithromycin using the serial two-fold agar dilution method. The genomic sequences of 23S rRNA genes were identified through next-generation sequencing, and nucleotide variants were determined based on comparison with genome sequences of the reference strain H. pylori 26695. Results: Clarithromycin resistance was found in 9 of 13 subjects before treatment and all subjects after unsuccessful eradication. Whole-genome sequencing of the 23S rRNA genes detected 42 mutations on 40 nonidentical loci, including 2147A>G (formerly 2143A>G) and 2146A>G (formerly 2142A>G). All strains with clarithromycin-resistant phenotype had either 2147A>G or 2146A>G mutation. When comparing genotype and phenotype for clarithromycin resistance, there was a significant association between 2147A>G mutation and clarithromycin-resistant phenotype. Conclusions: All clarithromycin-resistant strains had either 2146A>G or 2147A>G mutation, suggesting that tests targeting these two mutations may be enough for the prediction of clarithromycin resistance in this population.

scholarly journals Molecular detection of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolates of chicken origin from East Java, Indonesia

2019 ◽  
Vol 12 (4) ◽  
pp. 578-583 ◽  
Author(s):  
Meutia Hayati ◽  
Agustin Indrawati ◽  
Ni Luh Putu Ika Mayasari ◽  
Istiyaningsih Istiyaningsih ◽  
Neneng Atikah
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Resistance Pattern ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Resistance Level ◽  
Extended Spectrum

Background and Aim: Klebsiella pneumoniae is one of the respiratory disease agents in human and chicken. This bacterium is treated by antibiotic, but this treatment may trigger antibiotic resistance. Resistance gene in K. pneumoniae may be transferred to other bacteria. One of the known resistance genes is extended-spectrum β-lactamase (ESBL). This research aimed to study K. pneumoniae isolated from chicken farms in East Java, Indonesia, by observing the antibiotic resistance pattern and detect the presence of ESBL coding gene within the isolates. Materials and Methods: A total of 11 K. pneumoniae isolates were collected from 141 chicken cloacal swabs from two regencies in East Java. All isolates were identified using the polymerase chain reaction method. Antimicrobial susceptibility was determined by agar dilution method on identified isolates, which then processed for molecular characterization to detect ESBL coding gene within the K. pneumoniae isolates found. Results: The result of antibiotic sensitivity test in 11 isolates showed highest antibiotic resistance level toward ampicillin, amoxicillin, and oxytetracycline (100%, 100%, and 90.9%) and still sensitive to gentamicin. Resistance against colistin, doxycycline, ciprofloxacin, and enrofloxacin is varied by 90.9%, 54.5%, 27.3%, and 18.2%, respectively. All isolates of K. pneumoniae were classified as multidrug resistance (MDR) bacteria. Resistance gene analysis revealed the isolates harbored as blaSHV (9.1%), blaTEM (100%), and blaCTX-M (90.9%). Conclusion: All the bacterial isolates were classified as MDR bacteria and harbored two of the transmissible ESBL genes. The presence of antibiotic resistance genes in bacteria has the potential to spread its resistance properties.

scholarly journals Antimicrobial resistance profile and resistance genes of Vibrio species isolated from giant freshwater prawn (Macrobrachium rosenbergii) raised in Iran

2018 ◽  
Vol 68 (1) ◽  
pp. 79 ◽  
Author(s):  
A. SHAKERIAN ◽  
M. D. BARTON ◽  
O. L. AKINBOWALE ◽  
F. KHAMESIPOUR
Keyword(s):  
Antibiotic Resistance ◽  
Fresh Water ◽  
Resistance Genes ◽  
Macrobrachium Rosenbergii ◽  
Vibrio Species ◽  
Freshwater Prawn ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Resistance Profile ◽  
Giant Freshwater Prawn

Because of raising of large-scale high density prawn aquaculture techniques, production of this prawn worldwide is facing a serious threat from fatal diseases caused by nodaviruses and bacteria, particularly from the Vibrio species. The development of antibiotic resistance by Vibrio represents a potential threat to human health by exchange of resistant genes to human pathogens through food chain. This study aimed to determine antibiotic resistance profile of Vibrio isolates from giant fresh water Prawns (Macrobrachium rosenbergii) raised in Iran and to detect some antibiotic resistance genes in the isolates. A total of fifty giant fresh water prawns were processed for isolation of Vibrio species during February 2015 to August 2015. Identification of Vibrio isolates was done following standard biochemical methods. Phenotypic resistance of the isolates as determined by agar dilution method while polymerase chain reaction (PCR) method was used to detect the presence of erm, tetS, strA and sul2 genes in the isolates. Out of 50 prawns, 31 (62%) isolates of Vibrio spp. were reported, of which 20 (40%) were identified as V. parahaemolyticus, 10 (20%) were V. vulnificus and 1 (2%) were V. cholera. Over 90% of the tested strains showed susceptibility to SXT, AZM and NIT. In addition, strA and tetS genes were detected in all isolated Vibrio species. StrA gene was identified in 6 V. parahaemolyticus strains and also ermB and sul2 genes were not present in the isolate of V. cholera. The occurrence of multidrug resistance strains in the environment could be an indication of excessive usage of antibiotics in agriculture and aquaculture fields. This study has shown that giant freshwater prawns raised in Iran habour multidrug resistant Vibrio species.

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

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.

scholarly journals Prevalence, Antibiogram and Molecular Characterization of Comunity-Acquired Methicillin-Resistant Staphylococcus Aureus in AWKA, Anambra Nigeria

2016 ◽  
Vol 10 (1) ◽  
pp. 211-221 ◽  
Author(s):  
Blessing Ike ◽  
Malachy C. Ugwu ◽  
Moses N. Ikegbunam ◽  
David Nwobodo ◽  
Chika Ejikeugwu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Binding Protein ◽  
Meca Gene ◽  
Latex Agglutination ◽  
Diffusion Method ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Penicillin Binding Protein ◽  
Carriage Rate ◽  
Molecular Features

Objectives:This study evaluated the prevalence, antibiogram and molecular features of CA-MRSA in Awka, Nigeria.Methods:Confirmation of MRSA was done by testing resistance to oxacillin (1µg), cloxacillin (5µg) and cefoxitin(30µg) on sterile Mueller Hinton agar supplemented with 4% sodium chloride. The MRSA strains were subjected to antimicrobial susceptibility testing using Kirby-Bauer disc diffusion method. Minimum inhibitory concentration was determined using agar dilution method. Penicillin binding protein 2a was detected through rapid latex agglutination assay while mecA gene was detected by polymerase chain reaction. A total of 142S. aureusisolates were obtained from 261 samples sourced from Staff, students and fomites of the Faculty of Pharmaceutical SciencesResult:The overall prevalence of MRSA was 22.6%. The carriage rate was higher in females (56.5%) than male (43.5%) and was highest in individuals of 20-30 years of age (57.65%). The MIC of the oxacillin sodium salt ranged from 4-32 μg/ml. The multi-antibiotic resistance indices show that 53.4% had Multiple Antibiotic Resistance Indexing (MARI) higher than 0.2. Penicillin binding protein 2a was detected in 8.4% of MRSA isolates, all from nasal carriage while mecA gene was detected in 5 of isolates.Conclusion:This study showed a very high prevalence of MRSA carriage among studied subjects.

scholarly journals Macrolide resistance in Helicobacter pylori: rapid detection of point mutations and assays of macrolide binding to ribosomes.

1997 ◽  
Vol 41 (12) ◽  
pp. 2724-2728 ◽  
Author(s):  
A Occhialini ◽  
M Urdaci ◽  
F Doucet-Populaire ◽  
C M Bébéar ◽  
H Lamouliatte ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Point Mutations ◽  
Restriction Enzymes ◽  
The United States ◽  
Drug Binding ◽  
Macrolide Resistance ◽  
Rrna Genes ◽  
23S Rrna ◽  
Dependent Manner ◽  
H Pylori

Resistance of Helicobacter pylori to macrolides is a major cause of failure of eradication therapies. Single base substitutions in the H. pylori 23S rRNA genes have been associated with macrolide resistance in the United States. Our goal was to extend this work to European strains, to determine the consequence of this mutation on erythromycin binding to H. pylori ribosomes, and to find a quick method to detect the mutation. Seven pairs of H. pylori strains were used, the parent strain being naturally susceptible to macrolides and the second strain having acquired an in vivo resistance during a treatment regimen that included clarithromycin. The identity of the strains was confirmed by random amplified polymorphic DNA testing with two different primers, indicating that resistance was the result of the selection of variants of the infecting strain. All resistant strains were found to have point mutations at position 2143 (three cases) or 2144 (four cases) but never on the opposite DNA fragment of domain V of the 23S rRNA gene. The mutation was A-->G in all cases except one (A-->C) at position 2143. Using BsaI and BbsI restriction enzymes on the amplified products, we confirmed the mutations of A-->G at positions 2144 and 2143, respectively. Macrolide binding was tested on purified ribosomes isolated from four pairs of strains with [14C]erythromycin. Erythromycin binding increased in a dose-dependent manner for the susceptible strain but not for the resistant one. In conclusion we suggest that the limited disruption of the peptidyltransferase loop conformation, caused by a point mutation, reduces drug binding and consequently confers resistance to macrolides. Finally, the macrolide resistance could be detected without sequencing by performing restriction fragment length polymorphism with appropriate restriction enzymes.

Abundance, diversity and mobility potential of antibiotic resistance genes in pristine Tibetan Plateau soil as revealed by soil metagenomics

2020 ◽  
Vol 96 (10) ◽  
Author(s):  
Bo Li ◽  
Zeng Chen ◽  
Fan Zhang ◽  
Yongqin Liu ◽  
Tao Yan
Keyword(s):  
Antibiotic Resistance ◽  
Microbial Diversity ◽  
Resistance Genes ◽  
Antibiotic Resistance Genes ◽  
Soil Samples ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Metagenomic Sequencing ◽  
Clinical Issue ◽  
Abundance And Diversity

ABSTRACT Widespread occurrence of antibiotic resistance genes (ARGs) has become an important clinical issue. Studying ARGs in pristine soil environments can help to better understand the intrinsic soil resistome. In this study, 10 soil samples were collected from a high elevation and relatively pristine Tibetan area, and metagenomic sequencing and bioinformatic analyses were conducted to investigate the microbial diversity, the abundance and diversity of ARGs and the mobility potential of ARGs as indicated by different mobile genetic elements (MGEs). A total of 48 ARG types with a relative abundance of 0.05–0.28 copies of ARG/copy of 16S rRNA genes were detected in Tibetan soil samples. The observed ARGs were mainly associated with antibiotics that included glycopeptide and rifamycin; the most abundant ARGs were vanRO and vanSO. Low abundance of MGEs and potentially plasmid-related ARGs indicated a low horizontal gene transfer risk of ARGs in the pristine soil. Pearson correlation and redundancy analyses showed that temperature and total organic carbon were the major environmental factors controlling both microbial diversity and ARG abundance and diversity.

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