Helicobacter Pylori Isolates Research Articles

Guillain – Barre syndrome associated with Helicobacter pylori isolates from rectal swabs of Four Patients: University of Benin Teaching Hospital Experience

Background: A Gram-negative bacteria known as Helicobacter pylori (H. pylori) is thought to be the cause of autoimmune gastrointestinal diseases. Additionally, this pathogen has been connected to peripheral neuropathies and extra-gastrointestinal illnesses with autoimmune sequelae. H. pylori may be involved in the 30% of GBS cases that Campylobacter jejuni is blamed for. Guillain-Barré syndrome (GBS) typically has a post-infectious aetiology. The Aim of the study is to show that rectal swabs to isolate Helicobacter pylori as a cause of Guillain - Barre syndrome should be a routine instead of gastric biopsy. Methods: The study was a Retrospective Cross Sectional Study. It involved a review of Case notes of Patients that were admitted in the Neurology Unit of UBTH from 2014-2019, been managed for Guillain-Barre syndrome associated with H. pylori infection and also a review of their Medical microbiology laboratory test records during management especially their rectal swab Microscopy, Culture and Sensitivity results. It has never been the practice of the Neurology unit to do rectal swabs for patients with Guillain - Barre syndrome, this was done by the medical microbiology unit that co-managed the patient. Patients with incomplete or missing medical data were excluded from the study. Results: Four case series of one male and three female patients, age ranged from 7 years to 23years with the mean age of 15 ± 8 years. The most common initial symptom was weakness in the extremities which was seen in all the patients. Motor deficit involved all four limbs in all the patients. The mode of onset was progressive in all the cases and ascending. History of peptic ulcer disease was present in all four patient and H. pylori was isolated from rectal swabs from all the patients. Three (75%) of the patient showed marked improvement on commencement of Omeprazole and erythromycin, while one (25%) ,did well on amoxicillin and Omeprazole. One (25%) had complications of bilateral patchy lower limb skin exfoliation and desquamation. A case of death was recorded. On discharge complete functional recovery was noted in two (50%), while one (33%) had partial recovery. Conclusion: This study of four case series highlights a relatively inexpensive and straightforward faecal specimen collection by rectal swab, and readily available faecal specimen compared with gastric biopsy specimen, in the laboratory diagnosis and isolation of Helicobacter pylori, a cause (among other causes) of Guillain-Barre Syndrome, which is a medical emergency in most cases.In addition Guillain-Barre Syndrome linked with H. pylori is not always a Post-infectious diseases because medications used to clear the gastrointestinal tract of Bacterial usually lead to recovery from the paralysis caused by Guillain-Barre Syndrome.

Genetic diversity of the oipA gene among Helicobacter pylori isolates and clinical outcome in Vietnam.

Outer inflammatory protein A (OipA), which is encoded by the oipA gene, can induce interleukin-8 secretion in gastric epithelial cells. The functional status of the oipA gene is regulated by the slipped-strand mispairing mechanism based on the CT dinucleotide repeat number in the 5' region. This study aimed to investigate the oipA functional status ("on/off") of Helicobacter pylori (H. pylori) and its association with gastroduodenal diseases in southwestern Vietnam. The cross-sectional study was conducted on 173H. pylori isolates from 173 patients with gastroduodenal diseases. Sanger sequencing was used to determine the functional status of oipA. Multivariable logistic regression analysis was performed to identify the association between oipA status and gastroduodenal diseases. The oipA "on" status accounted for 96% of H. pylori isolates. Twenty-five CT repeat patterns of the oipA 5' signal region were observed, five of which were novel CT repeat patterns. The oipA "on" status was found in 100%, 97.8%, and 86.8% of H. pylori isolates from patients with peptic ulcer, precancerous lesions, and chronic gastritis, respectively (p<0.01). The oipA "on" status was related to gastric precancerous lesions versus chronic gastritis (adjusted OR=7.39, 95% CI: 1.35-40.59, p=0.021) and peptic ulcers versus chronic gastritis (adjusted OR=12.79, 95% CI: 1.19-1760.32, p=0.033). Our data show a high prevalence of the oipA "on" status, which was associated with precancerous gastric lesions and peptic ulcers. Moreover, genetic diversity in the number and pattern of CT dinucleotide repeat of oipA among Vietnamese H. pylori strains was identified.

Effect of dilution factor on the isolation of Helicobacter pylori from municipal wastewater using culture technique.

Isolating Helicobacter pylori (H. pylori) from wastewater and culturing it using a conventional method has always been a controversial issue because the bacterium converts into a coccoid form when exposed to an unfavourable environment like wastewater. To clarify the cultivability behaviour of the bacterium in fresh wastewater samples, the effect of municipal wastewater dilation on the cultivation of the bacterium using a conventional method was examined. Several dilutions of wastewater samples were inoculated with fresh H. pylori suspension (with McFarland's dilution 0.5) to examine the dilution effect of wastewater on the bacterium isolation. The H. pylori growth was found to be possible for a dilution factor from 1/106 to 1/107 of raw wastewater. In higher dilution factors the growth of fungi was dominant and could prevent the isolation of the bacterium. The optimized technique could be applied in future studies for increasing the chance of H. pylori isolation from fresh wastewater environments.

Antibiotics Resistance Prevalence of Helicobacter pylori Strains in Northwest China.

PurposeThis study aims to estimate the resistance rate of Helicobacter pylori (HP) to commonly used antibiotics and analyze the potential influencing factors in northwest regions of China.Patients and MethodsHP-positive patients visiting the outpatient department of multiple hospitals were enrolled in the study. Then, gastric mucosal biopsy specimens were collected for HP isolation, culture, and investigation of the resistance rate of HP to amoxicillin, metronidazole, tetracycline, levofloxacin, and clarithromycin by Epsilometer test (E-test) antibiotic susceptibility testing. In addition, multi-drug resistance, the influence of HP eradication history, age, and region of residence on drug resistance rate were analyzed.ResultsIn total, 198 HP clinical strains were successfully isolated and cultured. The resistance rates of amoxicillin, metronidazole, tetracycline, levofloxacin, and clarithromycin were 16.16%, 85.86%, 7.58%, 46.46%, and 55.05%, respectively. The multi-drug resistance rates demonstrated that dual and triple resistances were 30.30% and 22.73%, respectively. The quadruple resistance rate reached 9.60%. Our results revealed that the prior eradication history of HP significantly increased levofloxacin and clarithromycin resistance. Metronidazole and levofloxacin resistances significantly differed among different age groups, which presented an upward trend with increasing age. Drug resistance rates varied with geographic regions, especially amoxicillin and clarithromycin resistance, which were highest in Hexi Corridor and Longnan regions.ConclusionThe current situation of HP resistance to common antibiotics is severe. Tetracycline is the most sensitive antibiotic, followed by amoxicillin, the first choice for HP eradication. However, the eradication failure of HP may lead to an increase in the resistance rate. Therefore, it is necessary to strengthen the standardized diagnosis and treatment of HP to improve the primary eradication rate.

Isolation of Helicobacter Pylori from Raw Milk and Study on Its Survival in Fermented Milk Products

Isolation of Helicobacter Pylori from Raw Milk and Study on Its Survival in Fermented Milk Products

EPIYA Motif Genetic Characterization from Helicobacter pylori Isolates in Distinct Geographical Regions of Iran.

This study aimed to determine the current EPIYA motifs of the cagA gene in Helicobacter pylori isolates from patients with gastric disorders, and evaluate the association between these patterns and the clinical outcome of H. pylori infection in different geographical regions of Iran. We examined 150 patients with gastrointestinal disorders from the central and eastern regions of Iran. The detection of H. pylori and screening of cagA was performed by polymerase chain reaction (PCR). The pattern of the motifs was determined by PCR followed by sequencing. The overall prevalence of H. pylori was 66.3% in eastern (Mashad) and 50.6% in the central (Isfahan) part of Iran. The frequency of cagA-positive strains in Mashad and Isfahan were 63.4% and 56.7%, respectively. The pattern of EPIYA motif was as follows: 43 (79.6%) ABC, 7 (12.9%) AB, 4 (7.4%) ABCC, and one (1.9%) ABCCC. We also identified a novel EPIYA C sequence motif which showed association with gastric cancer (GC). The relationship between the frequency of specific EPIYA motifs and GC was statistically significant (P < 0.05). This is the first report for the determination of the cagA EPIYA motif of H. pylori in the Northeast and center of Iran. The prevalence of cagA positive H. pylori between the two regions was significant (P ≤ 0.05). All isolates of the H. pylori cagA were western type (ABC). The increase in the number of EPIYA-C repeats was associated with GC (P ≤ 0.01).

A Cross-Sectional Study on Molecular Detection of Helicobacter pylori cytotoxin-associated gene A and 16SrRNA Gene from Gastric Biopsy Specimens.

Introduction:The aim of the study is relative proportion of cytotoxin-associated gene A (cagA) virulence marker in Helicobacter pylori isolates and gastric biopsy samples by polymerase chain reaction (PCR).Methods:This cross-sectional study was conducted at a tertiary care hospital setting. Gastric biopsy tissues from 200 patients, suffering from upper gastrointestinal tract disorders, were examined for H. pylori infection using methods, such as hematoxylin and eosin (H and E) staining, 16S rRNA (Ribosomal ribonucleic acid), and cagA gene PCR. Chi-square and kappa statistics were used to find the association and agreement between the tests, respectively; P ≤ 0.05 was considered statistically significant. Screening tests' accuracy was calculated in terms of sensitivity and specificity along with positive and negative predictive values.Results:Out of 200 patients, H. pylori was detected in 14.5%, 48.5%, and 31% patients by H and E staining, 16S rRNA, and cagA PCR, respectively. Sensitivity and specificity of cagA PCR as compared to H and E staining were 89.6% and 78.9%, respectively.Conclusions:CagA detection directly from biopsy specimen by PCR can potentially and rapidly determine the patient's status, especially when at a higher risk of peptic ulcer.

Prevalence, diagnosis and antibiotic resistance pattern of H. pylori in the patients with heterogeneous gastroduodenal disorders

Background: Isolation of Helicobacter pylori (H. pylori) from gastric biopsies by Warren and Marshall has transformed our perception of gastro duodenal disorders. In India with miscellaneous environmental, dietary and lifestyle factors, it's common to acquire H. pylori infections. So screening becomes imperative for its early diagnosis and treatment. We intend to correlate the infection with diverse risk factors and also to appraise all microbiological diagnostic modalities with its local antibiogram. Methods and materials: Nine hundred and seventeen (n = 917) consecutive, symptomatic patients (562 males and 355 females) attending the endoscopy unit at a tertiary care center, Gujarat, India, were included. Four fragments of antral biopsies in a sterile Brain-heart infusion broth were processed for Rapid Urease Test (RUT), Gram's staining, Histopathology and Culture. Serum samples were tested for IgG antibody by ELISA. Susceptibility test was done by Kirby-Bauer disk diffusion method. Results: We found low Prevalence rate of H. pylori infection (15.2% 140/917). Symptoms of persistent gnawing abdominal pain (73%) was significantly associated with H. pylori infection (p < 0.01). Infection was mainly found in the patients with gastritis (44.2%), followed by reflux esophagitis (39%) and peptic ulcer disease (9.2%).The prevalence was higher in males (65%) probably due to their addictive habits to smoking/alcohol/tobacco. Amongst all the diagnostic techniques, serology was found 98.8% sensitive followed by Gram staining (96.8%) and histopathology (83%). Culture was 100% specific followed by RUT (99%). The combination of RUT with Gram's staining showed highest agreement of 95%. 83.8% of strains were resistant to metronidazole with a rising resistance to amoxicillin (72%) and clarithromycin (58%). Conclusion: Male gender, older age, chewing tobacco, Gastritis were individual risk factor associated to H. pylori infection. Combination of Gram staining and RUT was the Gold standard diagnostic test. Study recommends the need of sensitivity profile regionally and periodically before the general use of an eradication schedule.

Proteomic and transcriptomic studies of BGC823 cells stimulated with Helicobacter pylori isolates from gastric MALT lymphoma.

BackgroundThe correlation between the infection of H. pylori and the occurrence of gastric MALT lymphoma (GML) has been well documented. However, the mechanism of how GML is caused by this bacterium is not well understood, although some immunologic mechanisms are thought to be involved.Materials and methodsIn this study, we performed both transcriptomic and proteomic analyses on gastric cancer cells infected by H. pylori isolates from GML patients and the gastric ulcer strain 26695 to investigate the differentially expressed molecular signatures that were induced by GML isolates.ResultsTranscriptomic analyses revealed that the differentially expressed genes (DEGs) were mainly related to binding, catalytic activity, signal transducer activity, molecular transducer activity, nucleic acid binding transcription factor activity, and molecular function regulator. Fifteen pathways, including the Wnt signaling pathway, the mTOR signaling pathway, the NOD-like receptor signaling pathway and the Hippo signaling pathway, were revealed to be related to GML isolates. Proteomic analyses results showed that there were 116 differentially expressed proteins (DEPs). Most of these DEPs were associated with cancer, and 29 have been used as biomarkers for cancer diagnosis. We also found 63 upstream regulators that can inhibit or activate the expression of the DEPs. Combining the proteomic and transcriptomic analyses revealed 12 common pathways. This study provides novel insights into H. pylori-associated GML. The DEPs we found may be good candidates for GML diagnosis and treatment.ConclusionsThis study revealed specific pathways related to GML and potential biomarkers for GML diagnosis.

Isolation of Helicobacter pylori using leftover tissue in the rapid urease test kit

Isolation of Helicobacter pylori is considered difficult because of the requirement of the additional biopsy tissue and the effort involved in the isolation of the bacterium. We investigated whether Hpylori can be cultured from tissue samples used for the rapid urease test (RUT). Totally, 174 specimens from 87 patients referred for endoscopy were prospectively included. During endoscopy, two biopsy specimens were obtained, one each from the gastric antrum and the corpus, and were placed into a commercially available RUT kit. After detection of urease activity, Hpylori was cultured using tissue leftover in the RUT, regardless of the result. Hpylori was successfully isolated using leftover tissue in 72.4% (63/87) of the patients. In 32 patients, Hpylori was isolated from both specimens, while in 31 patients, it was isolated from either antrum or corpus. Eighty-one Hpylori strains were isolated from 141 specimens with positive RUT results (57.4%), whereas 14 strains were isolated from 33 specimens with negative RUT results (42.4%). The median interval between tissue acquisition and inoculation onto the isolation media was 3.6hours (range: 0.5-27.5hours) in cases with successful cultures, compared to 23.5hours (range: 0.5-76.0hours) in cases with failed cultures. Among the positive RUT tissues, 80.4% (45/56) were cultured successfully when the tissue was inoculated within 4hours of the biopsy. RUT kits can be used as transport media for Hpylori, and this media is most efficient when used within 4hours of the test.

Variations in cag pathogenicity island genes of Helicobacter pylori from Latin American groups may influence neoplastic progression to gastric cancer

Helicobacter pylori (HP) colonizes the human stomach and induces acute gastritis, peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Increased virulence in HP isolates derives from harboring the cag (cytotoxin-associated genes) pathogenicity island (cagPAI). We analyzed the microvariants in cagPAI genes with the hypothesis that they may play an important role in determining HP virulence. We tested DNAs from cagA positive patients HP isolates; a total of 74 patients with chronic gastritis (CG, N = 37), intestinal metaplasia (IM, N = 21) or gastric cancer (GC, N = 16) from Mexico and Colombia. We selected 520 non-synonymous variants with at least 7.5% frequency in the original sequence outputs or with a minimum of 5 isolates with minor allele. After adjustment for multiple comparisons, no variants were statistically significantly associated with IM or GC. However, 19 non-synonymous showed conventional P-values < 0.05 comparing the frequency of the alleles between the isolates from subjects with gastritis and isolates from subjects with IM or GC; 12 of these showed a significant correlation with the severity of the disease. The present study revealed that several cagPAI genes from Latin American Western HP strains contains a number of non-synonymous variants in relatively high frequencies which could influence on the clinical outcome. However, none of the associations remained statistically significant after adjustment for multiple comparison.

Resistance to Amoxicillin and Clarithromycin in Helicobacter pylori isolates in a tertiary care hospital

Introduction: Amoxicillin and Clarithromycin are the two most often chosen first line drugs in eradication therapy for H. Pylori, owing to their better efficacy. Unlike other bacterial infections, therapy here is not based on individual susceptibility report for this bacterium. Rather an empirical regimen is chosen based on the prevalent resistance report in a given population. Current study is aimed at determining the resistance rate in our study population for amoxicillin (AMX) & Clarithromycin (CLA) and to determine if these two drugs can be continued as first line regimen. Materials and Methods: Gastric biopsy samples from 165 dyspeptic patients obtained through endoscopy was cultured in Brucella Chocolate agar (BCA). Among them 46 samples were showing sufficient growth of H. Pylori for antibiotic susceptibility testing. MIC for AMX and CLA was determined by E-strip method based on standard guidelines. Results: 91.3 percent of isolates were susceptible or moderately susceptible to CLA. Percentage of isolates within the proposed epidemiological cut off for AMX was 76. Conclusion: H.pylori isolates in our study population had resistance rate well below the cut off (20%) for CLA and it could be safely used as first line regimen in treating patients from this region of the country. On the contrary, more than 20% of the strains had MIC above the proposed Epidemiological cut off for AMX. Hence an increase in dosage and frequency of dosage, in combination with a potent anti-H.pylori drug could be used in treatment. Clinical trials are required to study efficacy of AMX based regimen in non susceptible patients. Serial monitoring of biological resistance is required for both these drugs, to determine the change in susceptibility pattern at the earliest. Keywords: Amoxicillin, Clarithromycin, Antibiotic susceptibility test, Minimum Inhibitory Concentration, Helicobacter pylori.

Mucoid and coccoid Helicobacter pylori with fast growth and antibiotic resistance.

In this study, one Helicobacter pylori isolate, from gastric biopsy of a dyspeptic patient that turned into mucoid-coccoid (MC) form upon consecutive subcultures, was identified. The culturability, antibiotic resistance, and lipid contents of MC were compared with those of non-mucoid (NM) spiral Hpylori. Mucoid-coccoid and NM Hpylori were subcultured on Brucella blood agar (BBA) and incubated under aerobic and microaerobic atmospheres at 37°C. Cultures were examined for colony characteristics and bacterial morphology after 1-3days. The isolates were identified by biochemical tests and detection of Hpylori-16S rDNA. Antibiogram was performed with currently used antibiotics for Hpylori eradication. Cellular lipid contents were extracted and analyzed by gas chromatography. Compared with pin-pointed and glistening colonies of NM Hpylori that appeared under microaerobic conditions, MC Hpylori grew well in consecutive subcultures under aerobic and microaerobic atmospheres and produced white patches of mucoid colonies. MC exhibited coccoid and NM spiral morphology. Both isolates were catalase, oxidase, and urease positive and contained 16S rDNA. Compared with NM that was susceptible to almost all the antibiotics, MC was resistant to all the antibiotics. Lipid analyses showed high frequency of unsaturated fatty acids and cholesterol in MC. Coccoid forms with high fatty acid and cholesterol contents that show resistance to antibiotics might resist against other stressful conditions such as gastric acidity and immune response. Moreover, mucoid property may enhance resistance of coccoids to stresses. With mucoid-coccoid lifestyle, Hpylori may establish a chronic infection refractory to antimicrobial therapy.

Analysis of antibiotic resistance and influencing factors for Helicobacter pylori in children

Objective To investigate the antibiotic resistance of Helicobacter pylori(Hp) isolates cultured from endoscopic gastric mucosal samples and influencing factors for antibiotic resistance in children. Methods From April 2013 to February 2016, Hp cultured from mucosa samples of the gastric antrum and the body of stomach was investigated in 246 patients with 13C breath test positive examined by gastroscopy.Resistance to Amoxicillin, Clarithromycin, Metronidazole, Tetracycline was tested for Hp by using E-test.The clinical data were collected from the patients, and the relationship among age, gender, endoscopic diagnosis, histological performance, eradication number factors and antibiotic resistance rate were analyzed. Results Of 246 specimens, 174 cases (70.7%) were positive.The overall antibiotic resistance rates of isolates obtained were 96.55% (168/174 cases), 57.47% (100/174 cases), 4.02% (7/174 cases), 1.15%(2/174 cases) with respect to Clarithromycin, Metronidazole, Tetracycline and Amoxicillin.An antibiotic resistance rate was 43.10% (75/174 strains), among which the Clarithromycin resistance rate was 93.33% (70/75 strains), and the Metronidazole resistance rate was 6.67% (5/75 strains). Double resistance rate was of 54.02%(94/174 strains), among which the resistances rate of Clarithromycin+ Metronidazole was 52.30%(91/94 strains), and the resistances rate of Clarithromycin+ Tetracycline was 1.72%(3/94 strains). Triple resistance rate of Clarithromycin+ Metronidazole+ Tetracycline was 1.15%(2/174 strains). Quadruple resistance rate of Clarithromycin+ Metronidazole+ Amoxicillin+ Tetracycline was 1.15%(2/174 strains). Factor analysis showed that the resistance rate of Clarithromycin in children who had failed in eradication therapy [98.7%(148/150 cases)] was higher than that in children who had not undergone eradication therapy [83.3%(20/24 cases)], and the difference was statistically significant(χ2=14.610, P 0.05). Conclusions Hp resistance rate to Clarithromycin, Metronidazole is very high in children, but it is relatively low to Amoxicillin and Tetracycline, and multiple antibiotic resistance is at high prevalence. Key words: Helicobacter pylori; Antibiotic resistance; Child

Mutant selection window of clarithromycin for clinical isolates of Helicobacter pylori

BackgroundClarithromycin-resistance is becoming a global health concern in the treatment of Helicobacter pylori (H. pylori). The mutant prevention concentration (MPC) represent the propensities of antimicrobial agents to select resistant mutants. The concentration range between the minimum inhibitory concentration (MIC) and the MPC is defined as mutant selection window (MSW). In this study, we aimed to determine the cause of increasing clarithromycin resistance by investigating the MSW for clinical isolates of H. pylori.ResultsA retrospective subgroup, which included 68 clarithromycin-sensitive H. pylori strains, was selected from a double-blind trial. The MICs and MPCs were determined using agar plate assays. Genotypic tests were performed using Sanger sequencing. All isolates were wild-type, and 33.82% (23/68) had a 0.016 mg/L MIC, 45.59% (31/68) had a 0.031 mg/L MIC, 16.18% (11/68) had a 0.062 ≤ MIC ≤ 0.125 mg/L, and 4.41% (3/68) had a 0.25 mg/L MIC. The MPC50/90 (mg/L) of the isolates were: 0.062/0.125, 0.125/0.5, 0.25/0.25 and 1/2, respectively. The MPCs showed a moderate correlation with the MICs (rs = 0.65, P < 0.0001). Using published data and MPC90, we calculated the time inside the MSW (TMSW) for low- and high-dose (200 or 500 mg bid) clarithromycin that were 6 and 0 h, 24 and 4 h, 15 and 2 h, 5 and 17 h for the strains with MICs (mg/L) of 0.016, 0.031, 0.062–0.125, and 0.25, respectively.ConclusionsThis study showed that in the clarithromycin-sensitive clinical isolates of H. pylori, low-dose clarithromycin may lead to decreased drug sensitivity or even clarithromycin resistance; strains with a 0.25 mg/L MIC display a high risk of treatment failure.

One piece biopsy for both rapid urease test and cultivation of Helicobacter pylori

Background & aimsIncreasing antibiotic resistance among Helicobacter pylori isolates and the unsuccessful attempts at eradication can impose many costs to both healthcare systems and patients. The present study intended to find a way from which H. pylori could be isolated from biopsies with less invasive procedures undertaken on infected patients. MethodsA biopsy specimen from each patient with gastric disorders was put into urea-containing agar. After two hours, the specimens were removed from agar and placed into tubes containing 1 ml 20% glucose solution. Then, the specimens were inoculated onto the Columbia agar and incubated under microaerophilic conditions. The grown colonies were identified as H.pylori based on the microbiology tests and PCR. ResultsOverall, 449 biopsy specimens were collected from the patients. Of all biopsies, 219 (48.8%) revealed positive results in the rapid urease test. Using the aforementioned method, 158 (35.2%) culture positive biopsy specimens were obtained. ConclusionThe researchers attempted to use one biopsy specimen for both rapid urease and culture tests. This method causes fewer injuries of gastric tissue and allows antimicrobial susceptibility testing and characterization in detail of the isolated organism.

Genotypic determination of resistance and heteroresistance to clarithromycin in Helicobacter pylori isolates from antrum and corpus of Colombian symptomatic patients

BackgroundThe effectiveness of Helicobacter pylori first-line treatment has decreased drastically with the rise of strains resistant to clarithromycin. Therapy failure has also been described in patients with infections by strains with dissimilar antimicrobial susceptibilities. The present study aims to estimate the prevalence of resistance and heteroresistance to clarithromycin in H. pylori isolates from antrum and corpus of Colombian patients.MethodsThe study material included 126 isolates from antrum and corpus biopsies from 63 symptomatic patients over 18 years old who had a gastric endoscopy performed on them between June 2014 to August 2016. PCR amplification and sequencing of the H. pylori 23S rDNA gene was performed to determine the presence of mutations associated with clarithromycin resistance. Random amplified polymorphic DNA analysis was implemented in cases of resistance and heteroresistance.ResultsThe overall frequency of resistance to clarithromycin was 38.1% (24/63 patients), of which 19 patients had resistant isolates in both stomach segments (14 with A2143G mutation and 5 with A2142G mutation), and 5 patients had a heteroresistant status. The remaining 61.9% (39/63 patients) presented only susceptible isolates. DNA fingerprinting analysis showed different patterns in 4/22 paired isolates.ConclusionsThe high prevalence of H. pylori clarithromycin-resistance obtained (> 15%) constitutes an alert for gastroenterologists and suggests the need for reconsideration of the current eradication regimen for H. pylori in the studied population. The data show that heteroresistance status is an additional factor to be considered in the assessment of resistance. In consequence, it is advisable to examine at least two biopsies from different gastric segments.

Effective antimicrobial activity of rifabutin against multidrug‐resistant Helicobacter pylori

Helicobacter pylori resistance to more than one antibiotic is the main reason for failure in bacterial eradication in a considerable number of patients. Rifabutin (RFB) with a broad-spectrum of antimicrobial therapy has been suggested for treatment of refractory multidrug-resistant infections. Helicobacter pylori isolates from 104 patients were examined for resistance to 5 currently used antibiotics and RFB, using agar dilution method. Twofold serial dilutions of antibiotics were used and MICs (μg/mL) determined as metronidazole (MTZ 8), clarithromycin (CLR 2), amoxicillin (AMX 1), tetracycline (TET 0.5), furazolidone (FRZ 0.5), and RFB (0.06). Of 104 H.pylori isolates, only 7 (6.7%) were sensitive to all the 6 antibiotics. However, 30 (28.8%) were resistant to one antibiotic, 28 (26.9%) to two, 19 (18.2%) to three, 14 (13.4%) to four, and 6 (5.7%) to five currently used antibiotics. Overall, 67(64.4%) of isolates were resistant to 2-5 currently used antibiotics and considered as multidrug-resistant (MDR), with 59 (88.1%) showing sensitivity to RFB and 8 (11.9%) resistance (P<0.05). Of 33 isolates resistant to both MTZ and CLR, 25 (75.7%) were sensitive to RFB and 8 (24.3%) resistant (P<0.05). In vitro antimicrobial effectiveness of RFB on MDR H.pylori including those with resistance to both MTZ and CLR was demonstrated. However, RFB efficacy decreased as the number of antibiotics responsible for MDR increased. Considering that RFB inhibits both extra- and intracellular H.pylori, it can be suggested as an effective antibiotic against of MDR H.pylori.

Antimicrobial resistance among Helicobacter pylori isolates in Alaska, 2000-2016.

Alaska Natives experience a high burden of Helicobacter pylori infection and concomitant high rates of gastric cancer. Additionally, the prevalence of antimicrobial-resistant H. pylori has been shown to be high in Alaska. In this study, antimicrobial resistance over time among sentinel surveillance isolates was evaluated and risk factors for carrying antimicrobial-resistant H. pylori were assessed. Through Alaska's H. pylori sentinel surveillance system, antral and fundal biopsies from Alaska Native patients undergoing esophagogastroduodenoscopy for clinical indications during 2000-2016 were collected and cultured. For positive cultures, minimum inhibitory concentrations (MICs) of metronidazole, amoxicillin, clarithromycin, tetracycline and levofloxacin were determined. A total of 800 H. pylori isolates obtained from 763 patients were tested. Resistance to metronidazole was most common (342/800; 42.8%), followed clarithromycin (238/800; 29.8%), both clarithromycin and metronidazole (128/800; 16.0%) and levofloxacin (113/800; 14.1%). Low proportions of isolates were resistant to amoxicillin and tetracycline. Levofloxacin resistance increased between 2000 and 2016 (P<0.001), but resistance to other antimicrobials did not change over time. Metronidazole and clarithromycin resistance were more common among women (P<0.001 for both), whilst levofloxacin resistance was more common among those with an urban residence (P=0.003). Metronidazole and levofloxacin resistance were more common among older patients (P<0.05). Between 2000 and 2016, a large percentage of H. pylori isolates received by the Alaska Sentinel Surveillance System demonstrated resistance to common antimicrobials. The surveillance system provides valuable information for clinicians to make informed treatment choices for patient with H. pylori.

Antimicrobial activity of ellagic acid against Helicobacter pylori isolates from India and during infections in mice.

Because of the rise in antimicrobial resistance, an inexpensive, diet-based treatment against Helicobacter pylori infection would be of great interest. The present study was performed to assess the in vitro effects of ellagic acid against clinical H. pylori strains that were resistant to antibiotics used for therapy and also to observe the morphological structure following treatment with ellagic acid. The effectiveness of ellagic acid in eradicating H. pylori infection in a murine (C57BL/6) infection model, one of the standard inbred mouse lines often used for experimental infection, was also assessed. A total of 55 strains were screened. The agar dilution method was used to determine the susceptibility of isolates to test compounds. Transmission electron microscopy was used to observe the morphology following treatment with ellagic acid. The antibacterial activity of ellagic acid in an H. pylori SS1-infected mouse model and its effect on gastric mucosal injury were determined by histology and PCR. Ellagic acid inhibited the growth of all 55 of the H. pylori strains tested. The MIC of ellagic acid ranged from 5 to 30 mg/L, showing its bactericidal properties in vitro. Ellagic acid also demonstrated anti-H. pylori efficacy in eradication of this organism in an in vivo model, as well as restitution and repair of H. pylori-induced gastric mucosal damage. The present study paves the way for the preventive and therapeutic use of ellagic acid against H. pylori infection and, thus, ellagic acid can be considered a promising antibacterial agent against H. pylori-associated gastroduodenal diseases in humans.