High efficacy of 1-week doxycycline- and amoxicillin-based quadruple regimen in a culture-guided, third-line treatment approach for Helicobacter pylori infection

BACKGROUND: Helicobacter pylori infection may persist after both first- and second-line current treatments. AIM: To assess the efficacy of a third-line, culture-guided treatment approach for the eradication of H. pylori. METHODS: Patterns of resistance were analysed in H. pylori isolates from 94 consecutive patients in whom H. pylori infection had persisted after two eradication attempts. Using the epsilometer test, susceptibility analysis was performed for amoxicillin, clarithromycin, metronidazole, tetracycline and levofloxacin. Patients were then treated with a culture-guided, third-line regimen: 89 patients with a 1-week quadruple regimen including omeprazole, bismuth, doxycycline and amoxicillin, and five patients with a 1-week triple regimen containing omeprazole, amoxicillin and levofloxacin or clarithromycin. RESULTS : Ninety-four subjects (100%) were resistant to metronidazole, 89 (95%) to clarithromycin, 29 (31%) to levofloxacin and five (5%) to tetracycline. No resistance to amoxicillin was found in any patient. Overall, H. pylori eradication was obtained in 90% of subjects. The quadruple regimen was effective in 81 patients (92% by per protocol and 91% by intention-to-treat analysis). Four patients (80%, both per protocol and intention-to-treat analysis) were H. pylori-negative after the triple regimen. CONCLUSIONS: A culture-guided, third-line therapeutic approach is effective for the eradication of H. pylori. Furthermore, the 1-week doxycycline- and amoxicillin-based quadruple regimen is a good third-line 'rescue' treatment option.     

The importance of the level of metronidazole resistance for the success of Helicobacter pylori eradication

AIMS: To evaluate the role of antibiotic susceptibility for the treatment outcome of proton pump inhibitor-dependent and independent Helicobacter pylori eradication regimens. METHODS: In a placebo-controlled clinical study of peptic ulcer patients with H. pylori infection, patients were randomized to receive lansoprazole, clarithromycin and tinidazole twice-daily, clarithromycin and tinidazole once-daily with lansoprazole or with placebo. Helicobacter pylori status was assessed by culture and antibiotic susceptibility by E-test minimal inhibitory concentration (MIC) in 205 clinical isolates. RESULTS: Primary resistance to clarithromycin and metronidazole was 1 and 76%, respectively. In metronidazole susceptible strains eradication rates were similar at > 90% for all treatment groups (P = 0.49). With low-level metronidazole resistance (4 microg/mL < MIC < 256 microg/mL), eradication rates were similar at >75% (P = 0.80). The major difference was found at high-level metronidazole resistance (MIC >or= 256 microg/mL) with 95%, 58% and 21% eradication in the lansoprazole, clarithromycin and tinidazole twice-daily, lansoprazole, clarithromycin and tinidazole once-daily and placebo, clarithromycin and tinidazole once-daily groups, respectively (P < 0.001). CONCLUSION: In the absence of antibiotic resistance, a once-daily therapy of only clarithromycin and tinidazole can achieve a high rate of H. pylori eradication. Such a combination could offer a simpler and cheaper treatment option for developing countries. The standard, twice-daily proton pump inhibitor-based triple therapy was shown to be efficient in H. pylori eradication even in the presence of high-level metronidazole resistance.     

Lansoprazole, levofloxacin and amoxicillin triple therapy vs. quadruple therapy as second-line treatment of resistant Helicobacter pylori infection

AIM: To test the efficacy of levofloxacin-based second-line therapy for resistant Helicobacter pylori infection. METHODS: One hundred and six patients who failed H. pylori eradication were randomized to receive (i) lansoprazole 30 mg, amoxicillin 1 g, levofloxacin 500 mg, all given twice daily for 7 days (LAL); or (ii) lansoprazole 30 mg twice daily, metronidazole 400 mg thrice daily, bismuth subcitrate 120 mg and tetracycline 500 mg four times daily for 7 days (quadruple). Post-treatment H. pylori status was determined by (13)C-urea breath test. RESULTS: Intention-to-treat and per-protocol H. pylori eradication rates were 57/60% for the LAL group and 71/76% for the quadruple group respectively. Metronidazole, clarithromycin, amoxicillin and levofloxacin resistance were found in 76%, 71%, 0% and 18% of patients, respectively. Levofloxacin resistance led to treatment failure in the LAL group. For patients with dual resistance to metronidazole and clarithromycin, the eradication rates were 79% in the LAL group (levofloxacin-sensitive) and 65% in the quadruple group (P=0.34). CONCLUSION: Lansoprazole, amoxicillin plus levofloxacin second-line therapy is comparable with quadruple therapy in efficacy. Subjects, especially those with dual resistance to metronidazole and clarithromycin, may consider levofloxacin-based therapy for levofloxacin-sensitive strains.     

High levels of dual resistance to clarithromycin and metronidazole and in vitro activity of levofloxacin against Helicobacter pylori isolates from patients after failure of therapy

Current treatment for Helicobacter pylori infections generally includes two or more antimicrobials (amoxicillin, clarithromycin, nitroimidazoles, tetracycline, etc.), but treatment fails in 10-20% of all cases, often because of drug resistance. Levofloxacin has been proposed as an alternative for these refractory infections. We examined 67 H. pylori isolates from patients unsuccessfully treated with amoxicillin, clarithromycin, metronidazole and levofloxacin. Minimum inhibitory concentrations determined with the epsilometer test revealed clarithromycin and metronidazole resistance in 91 and 82.1% of the isolates, respectively; 52 (77.6%) were resistant to both drugs. All 67 isolates were susceptible to amoxicillin and tetracycline. Fifty-two isolates had levofloxacin MICs of 0.01-2 mg/l; the remaining 15 (22.4%), all clarithromycin- and metronidazole-resistant, had MICs >/= 8 mg/l. Levofloxacin may be an option for refractory H. pylori infections, but the choice should be based on in vitro susceptibility data, and physicians should consider local resistance patterns when treating these infections empirically.     

Esomeprazole-based one-week triple therapy with clarithromycin and metronidazole is effective in eradicating Helicobacter pylori in the absence of antimicrobial resistance

AIM: This study aimed to investigate the effectiveness of a one-week triple therapy with esomeprazole, clarithromycin and metronidazole for eradication of Helicobacter pylori infection in the absence of antimicrobial resistance. METHODS: Patients testing positive for H. pylori susceptible to metronidazole and clarithromycin (E-test) were randomized to receive a one-week regimen with either esomeprazole 2 x 20 mg or omeprazole 2 x 20 mg in combination with clarithromycin 2 x 250 mg and metronidazole 2 x 400 mg. Follow-up endoscopy with histology and culture and/or rapid urease test was performed 4-8 weeks after the end of treatment. RESULTS: Eighty patients were randomized. Helicobacter pylori infection was cured in 38/39 patients of the esomeprazole group and 31/33 patients of the omeprazole group (per protocol 97.4% (95% confidence interval [CI], 86.2-99.9), 93.7% (95% CI, 79.2-99.2), P=0.59); intention-to-treat 90.4% (95% CI: 77.4-97.3), 81.6% (95% CI: 65.7-92.3), respectively. No major side effects occurred. Minor side effects occurred in eight (20%) and six (23%) patients during esomeprazole and omeprazole therapy, respectively. Post-treatment susceptibility testing revealed resistance to both metronidazole and clarithromycin in two of the three patients who failed. CONCLUSION: We conclude that esomeprazole, clarithromycin and metronidazole as one-week triple therapy is effective for eradication of H. pylori in the absence of antimicrobial resistance.     

High prevalence of Helicobacter pylori infection with dual resistance to metronidazole and clarithromycin in Hong Kong

BACKGROUND: Metronidazole resistance is a common problem in most Asian countries, and clarithromycin has been widely used in Hong Kong. AIM: To determine the prevalence of Helicobacter pylori strains resistant to metronidazole and clarithromycin in Hong Kong and to assess the effect on eradication rates. Also to determine the genetic mutation in relation to phenotypic divergence in clarithromycin-resistant strains. METHODS: H. pylori were cultured from gastric biopsies obtained from 87 patients during upper endoscopy. Minimal inhibitory concentrations of metronidazole and clarithromycin were determined by Etest and agar dilution methods. Mutations in clarithromycin-resistant strains were identified by polymerase chain reaction and restriction analysis. Random amplified polymorphic DNA fingerprinting was performed on clarithromycin-resistant and susceptible isolates. RESULTS: The prevalences of H. pylori strains resistant to metronidazole and clarithromycin were 49.4% and 10.8%, respectively, in Hong Kong. Dual resistance to metronidazole and clarithromycin were found in 7. 2% of patients. The agreement between E-test and agar dilution methods was determined by error-rate bound analysis as 95.4% for metronidazole and 100% for clarithromycin. Dual resistant strains reduced the eradication rate to 66.7%. Among clarithromycin-resistant strains tested, all were due to A2144G point mutation in 23S rRNA gene. Random amplified polymorphic DNA fingerprinting suggested various phenotypically mixed populations. CONCLUSIONS: The prevalence of metronidazole-resistant H. pylori strains remained static whilst the prevalence of clarithromycin-resistant strains was not rare in Hong Kong. An alarming 7.2% of patients were resistant to both the antimicrobials, which had a definite impact on treatment success. All cases of resistance to clarithromycin were due to A2144G mutation in 23S rRNA of H. pylori.     

Primary Helicobacter pylori resistance to metronidazole and clarithromycin in the Finnish population

AIM: To systematically determine Helicobacter pylori primary antimicrobial resistance in Finland and the associated demographic and clinical features. METHODS: A total of 342 adult patients referred for gastroscopy at 23 centres in different parts of Finland and positive for the rapid biopsy urease test were recruited. Clinical and demographic data were collected via a structured questionnaire. Patients with positive H. pylori culture and successful antibiotic sensitivity determination by the E-test method (n = 292) were included in the present analysis. RESULTS: The study population consisted of 134 men and 158 women, mean age 56 years (95% CI, 55-58 years). Resistance to metronidazole was 38% (110 of 292) and to clarithromycin 2% (seven of 292). Resistance to metronidazole was higher in women than in men (48% vs. 25%, P < 0.001). Previous use of antibiotics for gynaecological infections predicted metronidazole resistance (P = 0.01), and previous use of antibiotics for respiratory (P = 0.02) and dental infections (P = 0.02) the clarithromycin resistance. We observed no major geographical variations in metronidazole resistance. CONCLUSIONS: The primary metronidazole resistance of H. pylori was 38% and was common in women previously treated for gynaecological infections. Primary clarithromycin resistance was uncommon (2%) and may associate with previous dental and respiratory infections.     

Primary resistance to antibiotics and its clinical impact on the efficacy of Helicobacter pylori lansoprazole-based triple therapies

AIM: To evaluate Helicobacter pylori primary resistance and its clinical impact on the efficacy of two lansoprazole-based eradication triple therapies. METHODS: H. pylori-positive patients (n=228) were randomized to receive one of the 1-week regimens: lansoprazole 30 mg, clarithromycin 500 mg and amoxicillin 1 g (LAC), or lansoprazole 30 mg, clarithromycin 500 mg and metronidazole 500 mg (LMC), each given twice daily. H. pylori status was assessed by 13C-urea breath test and culture at diagnosis and by 13C-urea breath test 6 weeks after therapy. Antibiotic susceptibility was determined by E-test (n=98). RESULTS: The eradication rates with per protocol/ intention-to-treat analyses were: LAC (n=95/114) 83%/69% and LMC (n=96/114) 85%/72%. Primary resistance was 11% for clarithromycin, 41% for metronidazole and 0% for amoxicillin. Eradication in metronidazole-susceptible/-resistant strains was 85%/82% in LAC and 83%/63% in LMC. Significantly lower cure rates were observed in clarithromycin-resistant patients treated with LAC (95% vs. 0%, P < 0.001) and LMC (86% vs. 0%, P < 0.001). CONCLUSIONS: One-week LAC and LMC are similarly effective therapies. Clarithromycin resistance significantly affected H. pylori eradication in both regimens.     

Famotidine versus omeprazole in combination with clarithromycin and metronidazole for eradication of Helicobacter pylori—a randomized, controlled trial

BACKGROUND: One-week low-dose triple therapy is currently considered the gold standard regimen for treatment of Helicobacter pylori infection. However, the mechanisms involved in the synergy between antibiotics and proton pump inhibitors are controversial. AIMS: To test the hypothesis that acid suppression represents the crucial mechanism by which the antibacterial activity of antibiotics can be enhanced, and to assess the impact of primary resistance on treatment outcome. METHODS: One hundred and twenty patients with H. pylori infection and duodenal ulcer, gastric ulcer or non-ulcer dyspepsia were randomly assigned to a 1 week course of either famotidine 80 mg b.d., clarithromycin 250 mg b.d. and metronidazole 500 mg b.d. (FCM group; n = 60) or omeprazole 20 mg o.d., clarithromycin 250 mg b.d. and metronidazole 500 mg b.d. (OCM group; n = 60). Gastroscopy was performed at baseline and 5 weeks after completion of treatment. H. pylori status was assessed by biopsy urease test, histology and culture. RESULTS: In the intention-to-treat analysis, eradication of H. pylori was achieved in 47 of 60 patients (78%; 95% CI: 66-88%) in the FCM group, compared to 44 of 60 patients (73%; 95% CI: 60-84%) in the OCM group (N.S.). Using per protocol analysis, eradication therapy was successful in 47 of 52 patients (90%; 95% CI: 79-97%) treated with FCM and 44 of 57 patients (77%; 95% CI: 64-87%) treated with OCM (N.S.). Primary metronidazole resistance was present in 27% and primary clarithromycin resistance in 8% of strains. Overall per protocol eradication rates in strains susceptible to both antibiotics and strains with isolated metronidazole resistance were 93% and 84%, respectively. No patient with clarithromycin resistance responded to treatment. CONCLUSIONS: High-dose famotidine and omeprazole, combined with clarithromycin and metronidazole, are equally effective for eradication of H. pylori. In 1-week low-dose triple therapy, metronidazole resistance has no major impact on eradication rates whereas clarithromycin resistance is associated with a poor treatment outcome.     

承德地区78株幽门螺旋杆菌耐药性分析

目的:分析承德地区幽门螺杆菌(helicobacter pylori,HP)临床分离株对多种抗幽门螺杆菌抗菌药物的药敏和耐药情况。方法:采用Kirby-Bauer药敏纸片法将12种抗菌药物对HP分离株进行药敏试验与耐药分析。结果:HP菌株对阿莫西林、阿莫西林/克拉维酸的敏感率为100%,对克拉霉素、罗红霉素、头孢他啶、妥布霉素、阿米卡星、莫西沙星、环丙沙星、左氧氟沙星、呋喃唑酮、甲硝唑的敏感率分别为97.43%,96.15%,89.74%,79.49%,73.08%,50.00%,33.33%,28.20%,11.54%和10.26%。结论:承德地区HP对阿莫西林、克拉霉素敏感率高,可作为首选用药;对甲硝唑、环丙沙星、左氧氟沙星敏感率较低,不宜常规选用。     

Primary antibiotic resistance in Helicobacter pylori strains isolated in northern and central Italy

BACKGROUND: Helicobacter pylori resistance to antibiotics is increasing worldwide, and it reduces the efficacy of therapy. AIM: To assess current primary antibiotic resistance in H. pylori strains isolated in Italy. METHODS: Between June 2004 and June 2006, H. pylori strains were isolated consecutively in the two participating centres (Bologna, northern Italy; Rome, central Italy) from patients never previously treated for the infection. Isolated strains were tested for primary clarithromycin, metronidazole and levofloxacin resistance using as break point the minimal inhibitory concentration >/=1, >/=8 and >/=1 mg/L for the three antibiotics, respectively. RESULTS: Overall, 255 H. pylori strains were evaluated. The resistance rate was 16.9% for clarithromycin, 29.4% for metronidazole and 19.1% for levofloxacin. Clarithromycin resistance was significantly higher in non-ulcer dyspepsia than in peptic ulcer patients (19.1% vs. 0%, P = 0.02), metronidazole resistance was higher in foreign than Italian patients (50% vs. 22.9%, P = 0.0004) and levofloxacin resistance was higher in old than younger patients (28.4% vs. 14.4%, P = 0.048). Levofloxacin resistance was also more frequent in those strains with either clarithromycin or metronidazole resistance. CONCLUSION: A very high rate of primary resistance towards the tested antibiotics was detected in our study.     

Randomized controlled study of rabeprazole,levofloxacin and rifabutin triple therapy vs. quadruple therapy as second-line treatment for Helicobacter pylori infection

AIM: To test the efficacy of rabeprazole, levofloxacin and rifabutin triple therapy vs. quadruple therapy for the second-line treatment of Helicobacter pylori infection. METHODS: One hundred and nine patients who had failed previous H. pylori eradication were randomized to receive: (i) rabeprazole, 20 mg b.d., rifabutin, 300 mg once daily, and levofloxacin, 500 mg once daily, for 7 days (triple therapy); or (ii) rabeprazole, 20 mg b.d., metronidazole, 400 mg t.d.s., bismuth subcitrate, 120 mg q.d.s., and tetracycline, 500 mg q.d.s., for 7 days (quadruple therapy). Endoscopy and culture were performed before treatment. RESULTS: The clarithromycin (79% vs. 21%, P < 0.001) and metronidazole (89% vs. 40%, P < 0.001) resistance rates were significantly higher in patients with previous exposure than in those with no previous exposure. The intention-to-treat and per protocol eradication rates were 91%/91% for the triple therapy group and 91%/92% for the quadruple therapy group. For patients with double resistance to metronidazole and clarithromycin, the eradication rates were 85% (17/20) in the triple therapy group and 87% (13/15) in the quadruple therapy group. Compliance was greater than 95% for both regimens. CONCLUSION: Rabeprazole, levofloxacin and rifabutin-based triple therapy and quadruple therapy were equally effective as second-line treatments for H. pylori infection.     

High prevalence and level of resistance to metronidazole, but lack of resistance to other antimicrobials in Helicobacter pylori, isolated from a multiracial population in Kuwait

BACKGROUND: The primary treatment regimen for Helicobacter pylori infection for Kuwaitis does not contain metronidazole, but that for expatriates does. There is also increasing failure of antimicrobial therapy. AIM: To determine the susceptibility of H. pylori from upper gastrointestinal biopsies of Kuwaitis and non-Kuwaitis to find out if differences existed in the susceptibilities of the isolates from the two different populations. METHODS: The susceptibilities of 96 H. pylori isolates were tested against metronidazole, amoxicillin, clarithromycin and tetracycline by the E test. The rdxA gene was analysed from selected metronidazole-susceptible and metronidazole-resistant strains to find out polymorphism and the basis of metronidazole resistance. RESULTS: Approximately, 70% of isolates from both populations were metronidazole resistant with 65% isolates showing high minimum inhibitory concentration values of >256 mug/mL. No resistance to the other three antimicrobials was found. There were novel nonsense and missense mutations with no deletion in the rdxA gene by insertion of mini-IS605. CONCLUSIONS: The prevalence and level of metronidazole resistance in H. pylori in the two populations was high with no difference, in spite of different treatment regimens. Metronidazole resistance in this transitional country appeared to be independent of prior metronidazole use for treatment of H. pylori infection.     

Ranitidine bismuth citrate with clarithromycin alone or with metronidazole for the eradication of Helicobacter pylori

BACKGROUND: Both triple therapy with ranitidine bismuth citrate (RBC) plus two antibiotics for 7 days and dual therapy of RBC with clarithromycin for 14 days have been extensively studied; both regimens effectively eradicate Helicobacter pylori. However, few studies have assessed the efficacy of dual therapy given for 7 days. AIM: To compare the efficacy and safety of RBC 400 mg with clarithromycin 500 mg, alone or with metronidazole 400 mg, given twice daily for 7 days for the eradication of H. pylori. METHODS: This single centre, randomized, double-blind study involved 118 patients with dyspepsia or a history of peptic ulcer disease. H. pylori infection was detected initially by CLO test, and confirmed in 109 patients by urea breath test and/or microbiology culture. H. pylori eradication was assessed 4 and 12 weeks after the end of treatment by urea breath test. H. pylori antibiotic susceptibility was assessed pre-study in all patients, and post-treatment in patients with a positive post-treatment urea breath test. Adverse events were recorded throughout the study. RESULTS: H. pylori was eradicated in 93% of patients who received RBC with clarithromycin and metronidazole and in 84% of patients who received RBC with clarithromycin (intention-to-treat rates). Per protocol eradication rates were 98% and 90% for triple therapy and dual therapy, respectively. The eradication of metronidazole-resistant H. pylori was achieved in 100% and 88% of patients following dual therapy and triple therapy, respectively, and acquired resistance to clarithromycin occurred in only one patient following treatment failure. Both treatments were well-tolerated; only one patient (2%) was withdrawn from each treatment group due to adverse events. CONCLUSIONS: RBC with clarithromycin and metronidazole is a highly effective and well-tolerated triple therapy regimen for the eradication of H. pylori. RBC with clarithromycin dual therapy has a similar efficacy, and offers an alternative to triple therapy when there are concerns about treatment with metronidazole or the use of multiple antibiotics. Both regimens are effective against antibiotic-resistant strains of H. pylori.     

Helicobacter pylori first-line treatment and rescue options in patients allergic to penicillin

BACKGROUND: Helicobacter pylori eradication is a challenge in patients allergic to penicillin, especially those who have failed a first-eradication trial. AIM: To assess the efficacy and tolerability of H. pylori first-line treatment and rescue options in patients allergic to penicillin. METHODS: Prospective single centre study including 40 consecutive treatments administered to patients allergic to penicillin. Therapy regimens: First-line (12 patients) omeprazole, clarithromycin and metronidazole for 7 days; second-line (17 patients) ranitidine bismuth citrate, tetracycline and metronidazole for 7 days; third-line (nine patients) rifabutin, clarithromycin and omeprazole for 10 days; and fourth-line (two patients) levofloxacin, clarithromycin and omeprazole for 10 days. Outcome variable: a negative (13)C-urea breath test 8 weeks after completion of treatment. RESULTS: Per-protocol/intention-to-treat eradication rates were: first-line (64/58%); second-line (ranitidine bismuth citrate; 53/47%); third-line (rifabutin; 17/11%) and fourth-line regimen (levofloxacin; 100/100%). Compliance with treatment was generally good, except with the rifabutin-based regimen, which presented adverse effects in 89% of the patients, including four cases of myelotoxicity. CONCLUSIONS: H. pylori-infected patients who are allergic to penicillin may be treated with a first-line treatment combining a proton-pump inhibitor, clarithromycin and metronidazole. Rescue options may include a regimen with ranitidine bismuth citrate, tetracycline and metronidazole. A levofloxacin-based rescue regimen (with proton-pump inhibitor and clarithromycin) may also represent an alternative, even when two or more consecutive eradication treatments have previously failed. However, rifabutin + clarithromycin + proton-pump inhibitor regimen is ineffective and poorly tolerated.     

One-week ranitidine bismuth citrate-based triple therapy for the eradication of Helicobacter pylori in Hong Kong with high prevalence of metronidazole resistance

AIM: To compare 1-week ranitidine bismuth citrate-based (RBC) triple therapy vs. omeprazole-based (O) triple therapy for the eradication of Helicobacter pylori infection in Hong Kong with high prevalence of metronidazole resistance. METHODS: Patients with non-ulcer dyspepsia and H. pylori infection were randomized to receive either: (i) RBCCM: ranitidine bismuth citrate (pylorid) 400 mg, clarithromycin 250 mg and metronidazole 400 mg; or (ii) OCM: omeprazole 20 mg, clarithromycin 250 mg and metronidazole 400 mg, each given twice daily for 1 week. Endoscopy (CLO test, histology and culture) and 13C-urea breath test were performed before randomization and 6 weeks after drug treatment. RESULTS: A total of 180 patients were randomized. H. pylori eradication rates (intention-to-treat, n=180/per protocol, n=166) were 83%/92% for RBCCM and 66%/70% for OCM (P=0.01, intention-to-treat and P=0.001, per protocol, respectively). RBCCM treatment was unaffected by metronidazole susceptibility and achieved a significantly higher eradication rate in metronidazole-resistant cases (89%) than the OCM group (45%, P=0.0064). CONCLUSION: One-week ranitidine bismuth citrate-based triple therapy is significantly better than omeprazole-based triple therapy for the eradication of H. pylori infection, especially in metronidazole-resistant cases. It is an effective regimen for the eradication of H. pylori infection in regions with a high prevalence of metronidazole resistance.     

琼脂稀释法检测5种抗菌药物对幽门螺杆菌的体外抑制效应

目的：探讨临床常用的5种抗菌药物对幽门螺杆菌（Hp）的体外抑制效应,旨在为临床根除Hp提供理论参考。方法：琼脂稀释法测定单药及联合用药对110株临床分离的Hp的最小抑菌浓度（MIC）和联合抑菌分数（FIC）。结果：110株Hp对5种抗菌药物的耐药率,左氧氟沙星为76.4%、克拉霉素为51.8%、替硝唑为20.9%、阿莫西林为8.2%、左奥硝唑为2.7%。5种抗菌药物的二联用药对Hp的抑制效应为：阿莫西林联合克拉霉素/左奥硝唑的协同抑制效应最强,替硝唑联合阿莫西林/左奥硝唑、左氧氟沙星联合阿莫西林/左奥硝唑具有协同抑制效应,克拉霉素联合左奥硝唑具有累加抑菌效应。结论：Hp对左氧氟沙星有较高的耐药性,对克拉霉素和替硝唑有一定的耐药性,对阿莫西林和左奥硝唑较敏感;阿莫西林联合克拉霉素/左奥硝唑对Hp的协同抑制效应最强。对根除Hp的治疗应在药物敏感性试验检测结果下选择性地应用抗菌药物。     

雷贝拉唑+克拉霉素+左氧氟沙星三联疗法治疗幽门螺杆菌消化道溃疡的观察

目的：观察雷贝拉唑＋克拉霉素＋左氧氟沙星三联疗法治疗幽门螺杆菌消化道溃疡的疗效。方法：60例幽门螺杆菌阳性消化道溃疡患者随机平分为两组,两组患者都采用三联一周疗法,治疗组为雷贝拉唑＋克拉霉素＋左氧氟沙星治疗,对照组为奥美拉唑＋阿莫西林＋甲硝唑治疗。结果：经过治疗,治疗组30例96.7%的总有效率明显高于对照组70.0%的总有效率（P＜0.05）;治疗组90.0%的HP根除率明显高于对照组66.7%的HP根除率（P＜0.05）。结论：雷贝拉唑＋克拉霉素＋左氧氟沙星三联疗法治疗幽门螺杆菌消化道溃疡能提高疗效,提高HP根除率,值得推广应用。     

左氧氟沙星对幽门螺杆菌体外抗菌活性的评价

目的 体外试验检测左氧氟沙星对幽门螺杆菌(Helicobacter.pylori)的敏感性，并以克拉霉索和阿莫西林进行对照研究。方法 琼脂稀释法检测左氧氟沙星对52株幽门螺杆菌的最低抑菌浓度，同时比较在MH培养基pH为4．0、5．0、7．0条件下的MIC。结果 左氧氟沙星耐药菌株1．9％，阿莫西林耐药菌株11．5％，克拉霉索耐药菌株25％。同时对阿莫西林和克拉霉索耐药的菌株(9．6％)，对左氧氟沙星均敏感。左氧氟沙星耐药率明显低于克拉霉素(P＜0．01)，阿莫西林的耐药率也低于克拉霉素(P＜0．05)，但与左氧氟沙星的耐药率无明显差异(P＞0．05)。左氧氟沙星在酸性环境下抗菌活性降低。结论 本地区幽门螺杆菌耐药菌株多见，左氧氟沙星是一种可供选择的治疗药物。     

Metronidazole and clarithromycin resistance amongst Helicobacter pylori isolates from a large metropolitan hospital in the United States

Background: Metronidazole and clarithromycin-based therapies are among the most efficacious treatment regimens for H. pylori infection. Resistance to metronidazole or clarithromycin is associated with impaired therapy with these agents. We conducted a retrospective review of susceptibility data to determine the frequency of primary metronidazole and clarithromycin resistance among H. pylori isolates from a single metropolitan hospital in the United States. The database comprised 933 patients who presented at the Digestive Diseases Clinic at the Veterans Affairs Medical Center in Houston between September 1988 and January 1997 with complaints of dyspepsia, abdominal pain and peptic ulcer disease. One hundred and seventy-nine of these patients had both pharmaceutical records available for evaluation and culture and antimicrobial susceptibility data for analysis. The MICs were determined by both E-test and broth microdilution tests. The frequency of primary metronidazole resistance was 37.4% (67/179). The level of primary clarithromycin resistance was 6.1%. Dual metronidazole and clarithromycin resistance was present in approx. 3%. The high level of primary metronidazole and clarithromycin resistance in H. pylori isolates from this metropolitan hospital is such that antimicrobial susceptibility data should be available so that informed choice can be made for specific eradication therapies, especially in patients who fail treatment.