Success of susceptibility-guided eradication of Helicobacter pylori in a region with high secondary clarithromycin and levofloxacin resistance rates

BACKGROUND Resistance to clarithromycin(CLA)and levofloxacin(LFX)of Helicobacter pylori(H.pylori)is increasing in severity,and successful eradication is essential.Presently,the eradication success rate has greatly declined,leaving a large number of patients with previous treatment histories.AIM To investigate secondary resistance rates,explore risk factors for antibiotic resistance,and assess the efficacy of susceptibility-guided therapy.METHODS We recruited 154 subjects positive for Urea Breath Test who attended The First Affiliated Hospital of China Medical University between July 2022 and April 2023.Participants underwent a string test after an overnight fast.The gastric juice was obtained and transferred to vials containing storage solution.Subsequently,DNA extraction and the specific DNA amplification were performed using quantitative polymerase chain reaction(qPCR).Demographic information was also analyzed as part of the study.Based on these results,the participants were administered susceptibility-guided treatment.Efficacy was compared with that of the empiric treatment group.RESULTS A total of 132 individuals tested positive for the H.pylori ureA gene by qPCR technique.CLA resistance rate reached a high level of 82.6%(n=109),LFX resistance rate was 69.7%(n=92)and dual resistance was 62.1%(n=82).Gastric symptoms[odds ratio(OR)=2.782;95%confidence interval(95%CI):1.076-7.194;P=0.035]and rural residence(OR=5.152;95%CI:1.407-18.861;P=0.013)were independent risk factors for secondary resistance to CLA and LFX,respectively.A total of 102 and 100 individuals received susceptibility-guided therapies and empiric treatment,respectively.The antibiotic susceptibility-guided treatment and empiric treatment groups achieved successful eradication rates of 75.5%(77/102)and 59.0%(59/411)by the intention-to-treat(ITT)analysis and 90.6%(77/85)and 70.2%(59/84)by the per-protocol(PP)analysis,respectively.The eradication rates of these two treatment strategies were significantly different in both ITT(P=0.001)and PP(P=0.012)analyses.CONCLUSION H.pylori presented high secondary resistance rates to CLA and LFX.For patients with previous treatment failures,treatments should be guided by antibiotic susceptibility tests or regional antibiotic resistance profile.

Clarithromycin的体内抗菌作用研究

新的１４元大环内酯ｃｌａｒｉｔｈｒｏｍｙｃｉｎ（ＣＲＭ）与红霉素（ＥＭ）对金葡球菌、化脓链球菌、肺炎链球菌、嗜血流感杆菌感染小鼠体内保护作用结果显示：口服ＣＲＭ对金葡球菌、化脓链球菌及肺炎链球菌的体内抗菌作用优于ＥＭ６．３～８．６倍。尤其对金葡球菌耐药菌及嗜血流感杆菌感染小鼠的半数保护剂量作用有效于ＥＭ的保护作用１７及１８倍，ＣＲＭ在体内具有良好的抗菌作用。

Clarithromycin的体外抗菌作用研究

评价国产ｃｌａｒｉｔｈｒｏｍｙｃｉｎ（ＣＲＭ）对临床分离到的４６４株致病菌的体外抗菌作用，并与红霉素（ＥＭ）、麦迪霉素（ＭＤＭ）、麦白霉素（ＭＬＭ）、柱晶白霉素（吉他霉素，ＬＵＭ）进行比较。结果表明ＣＲＭ对ＥＭ敏感的金葡球菌、表葡球菌、肺炎链球菌和化脓链球菌的抗菌作用优于ＥＭ，明显优于其它３种同类对照药，ＭＩＣ（９０）为０．０６２～２ｍｇ／Ｌ；对部分ＥＭ耐药的表葡球茵，化脓链球菌和粪链球菌也有一定的抗菌作用；对流感嗜血杆菌和对ＥＭ敏感的粪链球菌的抗菌作用同ＥＭ，优于其它３种同类对照药，ＭＩＣ_（９０）为０．５～２ｍｇ／Ｌ；对部分厌氧菌也有一定的抗菌作用，细菌接种量对ＣＲＭ的抗菌作用有一定的影响，但仍在敏感范围之中；ｐＨ值的变化影响ＣＲＭ抗菌作用，其抗菌作用在碱性条件下较强，尤以ｐＨ８．５时为显著；少量的人血清不影响ＣＲＭ的抗菌作用，但浓度加至７５％，ＣＲＭ的抗菌作用减弱。

国产clarithromycin片治疗急性细菌性感染临床研究

采用非盲随机对照临床验证设计，治疗药物为国产ｃｌａｒｉｔｈｒｏｍｙｃｉｎ（ＣＲＭ）片，对照药物为国产琥珀酸乙酰红霉素片，共治疗急性细菌性感染１７５例，其中随机对照１３４例（治疗组与对照组各６７例），开放治疗组４１例。结果显示ＣＲＭ片对１０８例患者总的临床痊愈率６４．８％，临床有效率９６．３％，细菌阴转率９６．９％，细菌清除率９６．３％，不良反应发生率７．４％。随机对照研究显示，治疗药对下呼吸道革兰氏阳性需氧菌感染以及口腔间隙厌氧菌感染的疗效与对照药比较均无显著性差异（Ｐ＞０．０５）。本验证细菌培养阳性１５３例，阳性率８７．４％，药敏试验显示了ＣＲＭ良好的体外抗菌作用。疗程结束时，治疗组中的９株耐药菌有８株被清除，反映ＣＲＭ的体内疗效更为显著。

国产clarithromycin治疗急性细菌性感染多中心临床研究

本项多中心临床研究旨在评价国产ｃｌａｒｉｔｈｒｏｍｙｃｉｎ（ＣＲＭ）的安全性和有效性。１２４例被确诊为急性呼吸道感染、皮肤软组织感染的成年患者入选随机对照试验。进口ＣＲＭ作对照药。患者被随机地分入国产或进口ＣＲＭ组。两药均按２５０ｍｇ，ｑ１２ｈ给药，疗程７～１４ｄ。国产ＣＲＭ组临床总有效率为９１．９％，细菌清除率９２．６％，不良反应发生率７．５％；对照组进口ＣＲＭ分别为９１．９％、９１．１％和７．６９％。以上结果经统计学处理，无显著性差异（Ｐ＞０．０５）。开放试验包括４５例急性细菌性感染病例，临床有效率为８６．７％，细菌清除率８７．８％，不良反应发生率６．７％。由以上结果可见，国产与进口ＣＲＭ治疗急性细菌性感染同样安全。

clarithromycin的研究进展及临床应用前景

clarithromycin(CAM)是新的大环内酯类抗生素,是红霉素(EM)的6位羟基被氧甲基取代的衍生物.该药抗菌机制与EM相似,但与EM相比,CAM有更广的抗菌谱、更高的血浓度和组织浓度、更广泛的细胞渗透性及更长的清除半衰期.加上它具有独特的药动学性质,使之成为临床治疗各类感染很有前途的药物.本文就CAM的基础和临床的研究进展综述如下.

Prevalence of primary Helicobacter pylori resistance to metronidazole and clarithromycin in Singapore

INTRODUCTIONEradication of Helicobacter pylori,a bacteriumresiding in stomach and causing peptic ulcer disease,can be achieved by using combination therapiesconsisting of one or two antibiotics with a protonpump inhibitor (PPI).The major antibiotics widelyused in the regimens to eradicate H.pylori aremetronidazole and clarithromycin.However,resistance to these antibiotics by H.pylori

Optimizing clarithromycin-containing therapy for Helicobacter pylori in the era of antibiotic resistance

The efficacy of triple therapy for Helicobacter pylori infection has dramatically declined over the last decade,largely related to increasing clarithromycin resistance rates.From a microbiological standpoint,bismuth quadruple therapy is the ideal replacement since it combines drugs for which resistance does not impair its efficacy.Nonetheless,several obstacles such as availability,complexity or tolerance prevent a general implementation of bismuth quadruple therapy,so nonbismuth quadruple regimens remain the best firstline treatment in clinical practice in many geographical areas.We review the rationale and efficacy of several optimization tools(increasing the length of duration,high-dose acid suppression,probiotics),which have been largely evaluated over the last 5 years to increase the effectiveness of standard triple therapy.Then,we update available evidence on the effectiveness of several non-bismuth quadruple therapies(sequential,concomitant,hybrid,miscellaneous therapy),which have gained interest lately.We also revise evidence on the efficacy of the aforementioned optimization tools for non-bismuth quadruples schemes and,finally we provide a novel regionalized therapeutic algorithm,based on novel formulas recently developed for predicting the outcome of non-bismuth quadruple regimens,upon local antibiotic resistance rates.

Punctual mutations in 23S rRNA gene of clarithromycinresistant Helicobacter pylori in Colombian populations

AIM To characterize punctual mutations in 23S rRNA gene of clarithromycin-resistant Helicobacter pylori(H. pylori) and determine their association with therapeutic failure.METHODS PCR products of 23S rRNA gene V domain of 74 H. pylori isolates; 34 resistant to clarithromycin(29 from a low-risk gastric cancer(GC) population: TumacoColombia, and 5 from a high-risk population: TuquerresColombia) and 40 from a susceptible population(28 from Tumaco and 12 from Túquerres) were sequenced using capillary electrophoresis. The concordance between mutations of V domain 23S rRNA gene of H. pylori and therapeutic failure was determined using the Kappa coefficient and Mc Nemar's test was performed to determine the relationship between H. pylori mutationsand clarithromycin resistance.RESULTS23S rRNA gene from H. pylori was amplified in 56/74 isolates, of which 25 were resistant to clarithromycin(20 from Tumaco and 5 from Túquerres, respectively). In 17 resistant isolates(13 from Tumaco and 4 from Túquerres) the following mutations were found: A1593 T1, A1653 G2, C1770 T, C1954 T1, and G1827 C in isolates from Tumaco, and A2144 G from Túquerres. The mutations T2183 C, A2144 G and C2196 T in H. pylori isolates resistant to clarithromycin from Colombia are reported for the first time. No association between the H. pylori mutations and in vitro clarithromycin resistance was found. However, therapeutic failure of eradication treatment was associated with mutations of 23S rRNA gene in clarithromycin-resistant H. pylori(κ = 0.71).CONCLUSION The therapeutic failure of eradication treatment in the two populations from Colombia was associated with mutations of the 23S rRNA gene in clarithromycinresistant H. pylori.

主要 clarithromycin 抵抗到 Helicobacter pylori : 这是为三倍的治疗失败的主要原因？

Conventional triple therapies for Helicobacter pylori (H. pylori ) eradication have recently shown a disappointing reduction in effectiveness in many countries. The main reason for failure was found to be bacterial resistance to one of the most commonly used antibiotics, clarithromycin. An additional problem for conventional triple therapy is the high rate of resistance to metronidazole found in Europe, America and Asia. In Italy, in the last 15 years a 2-fold increase in resistance has occurred. A recent study of the whole of Italy included about 20 patients from each region at the first endoscopic diagnosis of H. pylori infection. The most surprising result was the patchy distribution of resistance, which was almost absent in two regions (one northern and one southern), although the highest prevalence was found in some regions of the South. In the paediatricpopulation we found a 25% prevalence of resistance in a sample of H. pylori positive children observed between 2002 and 2007, mirroring data obtained in southern European countries. Clarithromycin resistance assessment is currently based on phenotypic detection performed after culture the agar dilution method or E-test, and genotypic methods based on polymerase chain reaction (PCR). In a recent comparative study we found a 71.2% agreement between the two methods. Culture-free techniques are highly accurate in finding even minimal traces of genotypically resistant strains. Moreover, PCR-based tools are accurate in detecting a heteroresistant status, defined as the co-existence of some strains that are susceptible and some resistant to the same antibiotic in an individual patient. Three point mutations, namely A2143G , A2142G and A2142C , are responsible for 90% of cases of primary clarithromycin resistance in H. pylori strains isolated in Western countries, although we previously demonstrated that the presence of the A2143G mutation, but not A2142G or A2142C , significantly lowered the H. pylori eradication rate. Treatment failure has considerable cost/benefit implications because of 'waste' of National Health System and patient resources, in terms of drugs, further diagnostic tests and medical examination expenses. Therefore, in future it would be very useful to be able to test for clarithromycin resistance before starting conventional triple therapy. Hopefully, fast, effective noninvasive tests may soon be devised to determine this condition.

Resistance to clarithromycin and gastroenterologist's persistence roles in nomination for Helicobacter pylori as high priority pathogen by World Health Organization

Due to the increasing prevalence of clarithromycin resistance, future of management of Helicobacter pylori(H. pylori) infections need to be recognized. To now, clarithromycin was the best effective, well-tolerated and safe antibiotic used in treatment of the bacterium, but, increasing trend of resistance reduced efficacy of recommended regimens. Indeed, gastroenterologists are mostly unable to start appropriate therapyaccording to the sensitivity profile-due to the certain difficulties in routine H. pylori culture procedure and being time consuming method. This announcement by World Health Organization(WHO) was an onset to reconsider current challenging dilemma about H. pylori clarithromycin resistant isolates. Therefore, investigating of various factors affecting this nomination by WHO is highly welcomed. In fact, WHO enumerated more than 16 pathogens which seriously threats human life and public health, thus better management or effective guidelines are necessary. Here for the first time, we nominated this phenomenon as ‘‘gastroenterologist's persistence'' which should be equally investigated as antibiotic resistance. The ability of gastroenterologists to win the game against H. pylori infections is highly influenced by their collaboration with diagnostic laboratories to apply susceptibility patterns before any prescription. In conclusion, closer collaboration between two important partners(gastroenterologists and microbiologists) in management of H. pylori infection may hopefully trigger an era to remedy current crisis in clarithromycin resistance, a later gastric cancer can be practically preventable.

Synthesis and antibacterial activity of 4″-O-carbamoyl analogs of clarithromycin

A series of novel 4'-O-carbamoyl analogs of clarithromycin were synthesized and evaluated for their in vitro antibacterial activity. All of the desired compounds showed excellent activity against erythromycin-susceptible S.pneumoniae.Particularly,4-fluorobenzyl carbamate 7a demonstrated potent activity against erythromycin-resistant S.pneumoniae encoded by the mef gene,and remarkably improved activity against erythromycin-resistant S.pneumoniae encoded by the erm gene,and the erm and mef genes.

Polymerase chain reaction-based tests for detecting Helicobacter pylori clarithromycin resistance in stool samples: A meta-analysis

BACKGROUND Helicobacter pylori(H.pylori)infection is closely associated with the etiology of a variety of gastric diseases.The effective eradication of H.pylori infection has been shown to reduce the incidence of gastric carcinoma.However,the rate of H.pylori eradication has significantly declined due to its increasing resistance to antibiotics,especially to clarithromycin.Therefore,the detection of clarithromycin resistance is necessary prior to the treatment of H.pylori.Although many studies have been conducted on the use of polymerase chain reaction(PCR)-based tests to detect clarithromycin resistance in stool samples,no accurate data on the feasibility of these tests are available.Here,we performed a meta-analysis to assess the feasibility of these noninvasive tests.AIM To evaluate the reliability of PCR-based tests for detecting H.pylori clarithromycin resistance in stool samples.METHODS We searched PubMed,Medline,Embase,and other databases for articles that evaluated the value of the PCR analysis of stool samples for detecting the resistance of H.pylori to clarithromycin.We collected cross-sectional studies that met the inclusion criteria.Diagnostic accuracy measures were pooled using a random-effects model.The risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool.Subgroup analysis was also conducted according to PCR type,purification technique,reference standard,mutation site,sample weight,number of patients,and age group,and the clinical utility of diagnostic tests was evaluated using the Likelihood Ratio Scatter Graph.RESULTS Out of the 1818 identified studies,only 11 met the eligibility criteria,with a total of 592 patients assessed.A meta-analysis of the random-effect model showed that PCR-based analysis of stool samples had high diagnostic accuracy for detecting clarithromycin resistance in patients infected with H.pylori.The combined sensitivity was 0.91[95%confidence interval(CI):0.83-0.95],Q=30.34,and I2=67.04,and the combined specificity was 0.97(95%CI:0.62-1.00),Q=279.54,and I2=96.42.The likelihood ratio for a positive test was 33.25(95%CI:1.69-652.77),and that for a negative test was 0.10(95%CI:0.05-0.18),with an area under the curve of 0.94.The diagnostic odds ratio was 347.68(95%CI:17.29-6991.26).There was significant statistical heterogeneity,and the sub-analyses showed significant differences in the number of patients,sample weight,purification methods,PCR types,mutation points,and reference standards.The included studies showed no risk of publication bias.CONCLUSION PCR-based tests on stool samples have high diagnostic accuracy for detecting H.pylori clarithromycin resistance.

An intravenous clarithromycin lipid emulsion with a high drug loading, H-bonding and a hydrogen-bonded ion pair complex exhibiting excellent antibacterial activity

The aim of this study was to develop an intravenous clarithromycin lipid emulsion(CLE)with good stability and excellent antibacterial activity. The CLE was prepared by the thinfilm dispersed homogenization method. The interaction between clarithromycin(CLA) and cholesteryl hemisuccinate(CHEMS) was confirmed by DSC, FT-IR and^1H NMR analysis. The interfacial drug loading, thermal sterilization, freeze–thaw stability, and in vitro and in vivo antibacterial activity were investigated systematically. DSC, FT-IR and^1H NMR spectra showed that CHEMS(CLA: CHEMS, M ratio 1:2) could interact with CLA through H-bonding and a hydrogen-bonded ion pair. The CHEMS was found necessary to maintain the stability of CLE.Ultracentrifugation showed that almost 88% CLA could be loaded into the interfacial layer.The optimized CLE formulation could withstand autoclaving at 121 °C for 10 min and remain stable after three freeze–thaw cycles. The in vitro susceptibility test revealed that the CLA–CHEMS ion-pair and CLE have similar activity to the parent drug against many different bacterial strains. The in vivo antibacterial activity showed that the ED50 of intravenous CLE was markedly lower than that of CLA solution administrated orally. CLE exhibited pronounced antibacterial activity and might be a candidate for a new nanocarrier for CLA with potential advantages over the current commercial formulation.

Detection of Helicobacter pylori resistance to clarithromycin and fluoroquinolones in Brazil:A national survey

AIM To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.METHODS The primary antibiotic resistance rates of Helicobacter pylori(H. pylori) were determined from November 2012 to March 2015 in the Southern,South-Eastern,Northern,North-Eastern,and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female,mean age 43 years(range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using Geno Type Helico DR(Hain Life Science,Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies,multiplex amplification,and reverse hybridization. RESULTS Clarithromycin resistance was found in 83(16.9%) patients,and fluoroquinolone resistance was found in 66(13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones(P = 0.55 and P = 0.06,respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3%(21/490) of patients. The A2147 G mutation was present in 90.4%(75/83),A2146 G in 16.9%(14/83) and A2146 C in 3.6%(3/83) of clarithromycin-resistant patients. In 10.8%(9/83) of clarithromycin-resistant samples,more than 01 mutation in the 23 S r RNA gene was noticed. In fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. D91 N mutation was observed in 34.8%(23/66),D91 G in 18.1%(12/66),N87 K in 16.6%(11/66) and D91 Y in 13.6%(9/66) of cases. Among fluoroquinolone-resistant samples,37.9%(25/66) showed mutations not specified by the Geno Type Helico DR test. CONCLUSION The H. pylori clarithromycin resistance rate in Brazil is at the borderline(15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate(13.5%) is equally concerning.

Study on the interaction between clarithromycin and bovine serum albumin in the imitated physiology solution

The interaction between clarithromycin (CAM) and bovine serum albumin (BSA) was investigated using linear-sweep voltammetry in pH 7.4 phosphate buffer solution where CAM caused two irreversible reduction waves P2 and P3 on mercury electrode. The study showed that the formation constant and formation ratio for the interaction between CAM and BSA were 1.51×1012 and 3:1 for P2,4.53×105 and 1:1 for P3, respectively. The ion strength enhanced the hydrophobic interaction between CAM and BSA.

Detection of genotypic clarithromycin-resistant Helicobacter pylori by string tests

AIM:To evaluate the utility of the string test to detect genotypic clarithromycin-resistant Helicobacter pylori (H.pylori)by polymerase chain reaction(PCR)-restriction fragment length polymorphism.METHODS:Patients undergoing endoscopic examinations were enrolled in the present study.String tests were done on the next day of endoscopy.Segments of 23S rRNA were amplified from DNA obtained from string tests.PCR-restriction fragment length polymorphism was accomplished by restriction enzymes BbsI and BsaI recognizing the mutation site A to G at 2143or at 2142 of 23S rRNA domain V,respectively.RESULTS:One hundred and thirty-four patients with H.pylori infection underwent string tests.To compare phenotypic resistance,43 isolates were successfully cultured in 79 patients in whom 23S rRNA was successfully amplified.Of five patients with clarithromycinresistant H.pylori,23S rRNA of H.pylori isolates from four patients could be digested by BsaI.In 38 susceptible isolates,23S rRNA of H.pylori isolates from 36 patients could not be digested by either BsaI or BbsI.The sensitivity and specificity of the string test to detect genotypic clarithromycin resistance were 66.7%and97.3%,respectively.Positive and negative predictive values were 80%and 94.7%,respectively.CONCLUSION:String test with molecular analysis is a less invasive method to detect genotypic resistance before treatment.Further large-scale investigations are necessary to confirm our results.

Microcalorimetric Study on the Antibiotic Activity of Clarithromycin and Erythromycin

By using LKB 2277 Bioactivity Monitoring System, the heat effect changes in the process of inhibitory action of clarithromycin and erythromycin on Escherichia coli at 37℃ were determined. Quantitativeanalysis showed that relationship between antibiotic concentration c and rate constant k of Escherichia coli growth, and half inhibitory ratio concentration IC 50 :clarithromycin: k = 0. 03003 1.1736 × 10 3 c , 8. 45 mg. L l ;erythromycin:k=0. 03108 8.4657×10 4 c , 14. 45 mg· L 1 . As a result of the microcalorimetry experiments, it not only indicated that antibacterial activity of clarithromycin was stronger than that of erythromycin, but also reported the changeable features of thermodynamics of the bacterial cell in biological,biochemical and metabolic process under different drug action.

Clarithromycin Attenuates the Bronchial Epithelial Damage Induced by <i>Mycoplasma pneumoniae</i>Infection

To analyze the bronchial epithelial cell damage induced by Mycoplasma pneumonia and the therapeutic effects of clarithromycin, we observed bronchial tissue damage by using a mouse model and performing immunostaining and scanning electron microscopy. The immunostaining study showed that M. pneumoniae-labeled fluorescence was found on the mucosal epithelium of mice, 6 days after inoculation. Clarithromycin treatment reduced the fluorescence. In this study, we demonstrated that the morphological alterations of bronchial mucosa, including the shortening and loss of ciliavisualized by scanning electron microscopy, and the inflammatory cell migration in the submucosal tissue visualized by differential interference contrast microscopy, were induced by mycoplasmal infection. We also showed that clarithromycin treatment, when administered from the first day of inoculation, attenuated both the bronchial epithelial damage and inflammatory cell migration in the submucosal tissue. These results suggest that the therapeutic effects of clarithromycin against mycoplasmal infection, may be due to its antibacterial and anti-inflammatory activities.