The distribution of minimal inhibitory concentrations (MIC) for amoxicillin, clarithromycin, metronidazole, tetracycline, azithromycin, and fluoroquinolone (ciprofloxacin, levofloxacin, and moxifloxacin) have shifted to higher concentrations from 1987 to 2003 in Helicobacter pylori (H. pylori) strains isolated from Korean patients. MIC values of secondary isolates were higher than those of primary isolates. Of treatment-failure patients, 16.4% showed mixed infections with both antibiotic-susceptible and -resistant H. pylori strains. A total of 89.6% of patients with treatment failure and 52.3% of patients without antibiotic treatment had H. pylori strains resistant to two or more antimicrobial agents (multi-drug resistance, MDR). The most common antibiotics showing MDR were clarithromycin, metronidazole, and azithromycin. The resistance rates to both amoxicillin and clarithromycin were 34.3% in secondary isolates and 6.2% in primary isolates. The resistance rates to both clarithromycin and metronidazole were 73.1% in secondary isolates and 7.7% in primary isolates. In addition, there was a significant difference in antibiotic resistance between two institutions located at Seoul and Gyeonggi provinces. To provide adequate informations about susceptible antibiotics to clinicians, continuous surveillance of antibiotic susceptibilities is needed in Korea.
*Drug Resistance, Bacterial ; Drug Resistance, Multiple, Bacterial ; Helicobacter pylori/*drug effects/isolation & purification ; Humans ; Korea ; Microbial Sensitivity Tests

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Child ; China ; Drug Resistance, Bacterial ; Female ; Helicobacter Infections ; microbiology ; Helicobacter pylori ; classification ; drug effects ; isolation & purification ; Humans ; Male ; Middle Aged ; Young Adult

OBJECTIVETo study the infection status of Helicobacter pylori (H. pylori) and sensitivity to commonly used antibiotics in Taizhou district,Zhejiang province.

METHODS39 099 cases aged between 5 and 95 years old (mean as 48.42 years) were involved during January 2010 to December, 2013 for this study. Sex ratio was 1 : 0.95. Yearly distribution of the number of cases were 5 031, 6 709, 11 902 and 15 457 in 2010, 2011, 2012 and 2013, respectively. Gastric mucosal specimens were collected and H. pylori strains were isolated and cultured in the same platform in Zhiyuan Medical Inspection Institute of Hangzhou. Resistance tests of all the H. pylori isolates were performed to 6 commonly used antibiotics:metronidazole, clarithromycin, amoxicillin, gentamicin, levofloxacin and furazolidone with the agar dilution method. The antibiotic resistance rates of H. pylori strains isolated during year 2010-2013 and the changing trends were analyzed.

RESULTSResistance rates to levofloxacin and clarithromycin kept at higher level and the highest was in 2011 and then decreased in both 2012 and 2013 (P < 0.01). The resistance rates to both levofloxacin and clarithromycin reached the highest in 2011 (P < 0.01), and decreased thereafter, with no significant change in 2013 to 2012 (P > 0.05).

CONCLUSIONAntibiotic resistance rate against metronidazole for HP isolate was highest. Resistance rate against amoxicillin and furazolidone, gentamicin was low. Clinical treatment should choose amoxicillin and furazolidone, gentamicin. The resistance rates to levofloxacin and clarithromycin had been seen at a significantly downward trend since 2011. However, the combined resistance rates to levofloxacin and clarithromycin did not seem to reduce since 2012.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anti-Bacterial Agents ; pharmacology ; Child ; Child, Preschool ; Drug Resistance, Multiple, Bacterial ; Helicobacter pylori ; drug effects ; isolation & purification ; Humans ; Middle Aged ; Young Adult

No abstract availble.
Anti-Bacterial Agents/therapeutic use ; Disk Diffusion Antimicrobial Tests ; *Drug Resistance, Bacterial ; Drug Therapy, Combination ; Helicobacter Infections/*drug therapy ; *Helicobacter pylori/drug effects/isolation & purification ; Humans ; Microbial Sensitivity Tests ; Peptic Ulcer/*drug therapy

BACKGROUND: This study was performed to determine the biopsy sites that are suitable for the diagnosis of Helicobacter pylori infection and to assess the sensitivity of culture, histology, and dual-priming oligonucleotide (DPO)-based multiplex PCR. Moreover, we evaluated the usefulness of PCR for the detection of 23S rRNA mutations, which are responsible for the clarithromycin resistance of H. pylori. METHODS: From 90 patients, we obtained biopsy specimens for culture, histology, and Seeplex(R) ClaR-H. pylori PCR (Seegene Inc., Korea). Phenotypic susceptibility to clarithromycin was evaluated using the E-test (AB Biodisk, Sweden). RESULTS: H. pylori was detected in 48 of 90 patients. The positive rates of infection in the antrum and body were higher than those in the biopsies obtained from the duodenal bulb. The positive rates in histology, PCR, and culture were 46.7%, 42.2%, and 34.4%, respectively. Using histology or PCR, we identified H. pylori in 46 of the 48 patients. 23S rRNA mutations were detected in 8 patients. The clarithromycin E-test showed that all the 10 wild-type patients were susceptible. However, the results of the PCR and E-test of 3 of the 8 mutation-positive patients were discrepant. CONCLUSIONS: We observed that a combination of histology and PCR affords a high detection rate of H.pylori infection and that DPO-based PCR can be practically used for the diagnosis of H. pylori infection and the determination of clarithromycin resistance. These techniques were useful for biopsy sampling simultaneously from the antrum and body for the detection of clarithromycin resistance of multiple strain infection or heteroresistance.
Anti-Bacterial Agents/*pharmacology ; Biopsy ; Clarithromycin/*pharmacology ; Drug Resistance, Bacterial ; Genotype ; Helicobacter Infections/*diagnosis/drug therapy/pathology ; Helicobacter pylori/drug effects/genetics/*isolation & purification ; Humans ; Microbial Sensitivity Tests ; Mutation ; Polymerase Chain Reaction ; RNA, Ribosomal, 23S/genetics

OBJECTIVEInfection with clarithromycin-resistant Helicobacter pylori (Hp) is often predictive of treatment failure. Susceptibility testing for Hp could guide therapy of Hp infections. However, agar dilution approved by the Clinical and Laboratory Standards Institute (CLSI) to test for antimicrobial susceptibility of Hp is time consuming (results are often not available in a week or more). So a more expeditious method is necessary. The purpose of this study was to evaluate polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) test performed directly on gastric biopsy specimen from children to detect 23S rRNA mutations (A2143G and A2144G) indicating clarithromycin resistance.

METHODSAll biopsy specimens were derived from patients presenting with upper gastrointestinal symptoms, submitted to endoscopy in the Affiliated Children's Hospital, Zhejiang University School of Medicine from September 2006 to February 2007. No patients had undergone eradication therapy. Thirty-nine samples randomly selected from positive specimens by rapid urease test, were homogenized in 500 microl brucella broth with 30% glycerol. The 200 microl homogenized fluid was used to purify genomic DNA with the kit according to the instructions provided by manufacturer, and the rest was used to isolate Hp strains by culturing. All the Hp isolates were tested for clarithromycin susceptibility with the agar dilution and classified as resistant if the minimum inhibitory concentrations (MIC) exceeded 1 microg/ml. Simultaneously, PCR-RFLP analysis was performed in order to identify 23S rRNA mutations (A2143G and A2144G). Finally, the two methods were compared by statistics. The agar dilution was used as a standard to determine the sensitivity and specificity of the PCR-RFLP assay.

RESULTSOf the 39 samples, agar dilution and PCR-RFLP method respectively detected 13 (33.3%) and 14 (35.9%) clarithromycin-resistant gastric specimens. The sensitivity and specificity of PCR-RFLP for the detection of Hp in biopsy specimens were both 92%. The positive and negative predictive value was 85.7% and 96% respectively. No statistically significant difference was found between the two methods (chi2=0.06, P>0.05). The rate of Hp resistance to clarithromycin significantly increased compared with a previous report from the authors' hospital in 2004 (chi2=6.20, P<0.05).

CONCLUSIONSRising clarithromycin resistance rates were observed in children who visited the authors' hospital. PCR-RFLP test is reliable and rapid for detection of clarithromycin resistance directly on gastric biopsy specimen from children and may help choose appropriate antibiotic in Hp eradication therapy.

Child ; Clarithromycin ; pharmacology ; Drug Resistance, Bacterial ; Gastric Mucosa ; microbiology ; Helicobacter Infections ; drug therapy ; Helicobacter pylori ; drug effects ; genetics ; isolation & purification ; Humans ; Microbial Sensitivity Tests ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Sensitivity and Specificity

OBJECTIVETo investigate the bactericidal effects of Jinghua Weikang Capsule and its major component Chenopodium ambrosioides L. on antibiotic-resistant Helicobacter pylori.

METHODSFour clinical antibiotic-resistant H. pylori strains were isolated and incubated in liquid medium containing Jinghua Weikang Capsule or Chenopodium ambrosioides L. By means of time-kill curve method, the average colony counts and bactericidal rate were calculated at time points of 0, 4, 8 and 24 h after the incubation and the time-kill curves were charted.

RESULTSBoth Jinghua Weikang Capsule and Chenopodium ambrosioides L. at a concentration of 0.64 g/L showed obvious bactericidal effect against antibiotic-resistant H. pylori after 4 h of incubation.

CONCLUSIONJinghua Weikang Capsule and Chenopodium ambrosioides L. are considered to be active against antibiotic-resistant H. pylori in vitro.

Anti-Bacterial Agents ; pharmacology ; Chenopodium ambrosioides ; Drug Resistance, Microbial ; Drugs, Chinese Herbal ; pharmacology ; Helicobacter Infections ; drug therapy ; physiopathology ; Helicobacter pylori ; drug effects ; isolation & purification ; Humans ; In Vitro Techniques ; Microbial Sensitivity Tests ; Plant Preparations ; pharmacology ; Sensitivity and Specificity

OBJECTIVETo investigate the prevalence of Helicobacter pylori (H. pylori) resistance to clarithromycin (CLM) in children and to demonstrate the correlation of 23S rRNA gene mutation to clarithromycin resistance of Helicobacter pylori isolates.

METHODSTotally 108 clinical strains of H. pylori were isolated from gastric biopsy specimens obtained from children who underwent endoscopy during the period from October 2002 to January 2004 in Children's Hospital Affiliated to Medical College of Zhejiang University. H. pylori was identified by morphology and biochemical tests after culture. Clarithromycin susceptibility of H. pylori isolates was determined by both E-test and two-fold agar dilution method. A strain was considered resistant when the MIC was defined as >or= 1 microg/ml. Genome DNAs of the 108 isolates were extracted and prepared for PCR to detect the corresponding gene in the V domain of the 23S rRNA. The amplified fragments were recognized and analyzed by restriction fragment length polymorphism (RFLP) when an additional restriction site is created by the mutation. The PCR products of all sensitive and resistant strains were digested with restriction enzyme BbsI and BsaI and were analyzed on a 1.5% agarose gel to discriminate different kinds of mutant genotype.

RESULTSSixteen of 108 isolates of H. pylori were resistant to clarithromycin by the agar dilution method and E-test method in clinical isolates from children, and the CLM resistance rate was 14.8% (16/108) with MICs ranging from 1 microg/ml to 128 microg/ml. Comparison of results of the two methods showed that these two methods were quite consistent in determination of susceptibility and resistance. The target fragment 425 bp in length containing 23S rRNA corresponding gene was successfully amplified. An A2144G mutation digested with BsaI was detected in 13 resistant isolates, but an A2143G mutation digested with BbsI in only 3 among all 16 clarithromycin resistant strains. None of the sensitive isolates was cleaved by either BsaI or BbsI enzyme, indicating that there was no mutation on them. It was also found that all the fragments from the resistant strains were not completely digested, and 425 bp uncut fragments were also visible and showed three bands indicating that they were heterozygotic strains with a mixture of wild-types and A-->G genotypes. In addition, in this study, no statistically significant difference between mutations at positions 2143 and 2144 with respect to the MIC was observed (r = 0.035, P > 0.05).

CONCLUSIONA high prevalence of clarithromycin-resistant H. pylori strains were detected among strains isolated from Chinese children studied. The 23S rRNA gene mutation at positions A2143G and A2144G plays an important role in clarithromycin resistance of H. pylori and A2144G mutation is the predominant finding among the resistant strains.

Anti-Bacterial Agents ; pharmacology ; Biopsy ; Child ; Clarithromycin ; pharmacology ; Drug Resistance, Bacterial ; genetics ; Genes, rRNA ; Helicobacter Infections ; epidemiology ; genetics ; Helicobacter pylori ; drug effects ; genetics ; isolation & purification ; Humans ; Microbial Sensitivity Tests ; Mutation ; Prevalence ; Stomach ; microbiology ; pathology

INTRODUCTIONThe use of an additional biopsy from the gastric body may help improve the detection of Helicobacter pylori during endoscopy. This study aimed to determine whether such an additional biopsy is necessary in routine rapid urease test (RUT), and whether acid suppression and antibiotic therapy affect RUT results.

METHODSPatients recruited had two gastric mucosal biopsies taken - one from the gastric antrum and the other from the gastric body. Each biopsy was placed into separate RUT kits. Information on previous or current use of proton-pump inhibitors, H2 receptor antagonist, bismuth and antibiotics was obtained. Patients on any of those drugs one week prior to endoscopy were considered to have a positive drug history (PDH).

RESULTSOf the 400 patients recruited, 311 had negative RUTs and 89 had at least one positive RUT. Between the PDH and negative drug history (NDH) groups, there was a significant difference in the distribution of the location of the biopsies that yielded positive RUTs (p = 0.023). The NDH group had a higher proportion of patients who had positive RUTs for both locations, whereas the PDH group had a higher proportion of patients who had positive RUTs for only one location.

CONCLUSIONAs RUT results are significantly affected by the use of acid suppression and antibiotic therapies, biopsies for RUT should be taken from both the gastric antrum and body to minimise false negative results.

Adult ; Aged ; Antacids ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; Endoscopy ; Endoscopy, Gastrointestinal ; Female ; Gastric Mucosa ; microbiology ; pathology ; Gastrointestinal Diseases ; diagnosis ; epidemiology ; microbiology ; Helicobacter Infections ; diagnosis ; Helicobacter pylori ; drug effects ; isolation & purification ; History, Ancient ; Humans ; Middle Aged ; Singapore ; epidemiology ; Urease ; analysis

OBJECTIVEMany clinical studies indicated that Helicobacter pylori (Hp) strains rarely acquired resistance to amoxicillin but easily to clarithromycin and metronidazole. However, it was unclear whether the antibiotic resistance of Hp strains was induced or passively selected during long-term or frequent treatment with metronidazole, clarithromycin and amoxicillin. To compare the propensity of acquired resistance to antibiotics, Hp strains were exposed to amoxicillin, clarithromycin and metronidazole in vitro in this study.

METHODSAll Hp strains were clinical isolates, derived from biopsy specimens of patients taken during endoscopy in the Affiliated Children's Hospital, Zhejiang University School of Medicine from December 2004 to July 2005. To seek susceptible strains, the minimum inhibitory concentrations (MICs) of the three antibiotics were determined by using Epsilometer test (E-test) method. In vitro induction was carried out on serially doubling concentrations of antibiotics incorporated into agar. Isolates were also transferred at least three times on antimicrobial agent-free medium, followed by a redetermination of the final MICs to assess the stability of the selected resistance.

RESULTS7 strains were exposed to antibiotics in vitro. After 6 - 17 passages on antibiotic plates, 7 and 3 strains respectively acquired resistance to metronidazole and clarithromycin, while none of the strains were resistant to amoxicillin. The inductive folds were different among three groups: 8 - 128 folds in metronidazole group; 1 - 256 folds in clarithromycin group; 2 - 16 folds in amoxicillin group. After three transfers on antimicrobial agent-free medium, the MICs decreased significantly in amoxicillin group (P < 0.05) but had no change in metronidazole group and clarithromycin group (P > 0.05).

CONCLUSIONSThe metronidazole resistance in Hp was easily selected. Strains resistant to clarithromycin could be selected, but the amoxicillin resistance could not be selected after in vitro induction for Hp isolated from children. The correlation between in vitro and in vivo outcomes suggests that acquired resistance was the main cause for the resistance in Hp strains. The laboratory results of in vitro antibiotic induction could help predict the actual rate of resistance and select appropriate antibiotics for treatment.

Amoxicillin ; pharmacology ; Anti-Bacterial Agents ; pharmacology ; therapeutic use ; Anti-Infective Agents ; pharmacology ; therapeutic use ; Biopsy ; Child ; Clarithromycin ; pharmacology ; Drug Resistance, Microbial ; drug effects ; Drug Resistance, Multiple, Bacterial ; drug effects ; Helicobacter Infections ; drug therapy ; microbiology ; Helicobacter pylori ; drug effects ; isolation & purification ; Humans ; Metronidazole ; pharmacology ; Microbial Sensitivity Tests ; methods ; Tetracycline ; pharmacology