Representativeness of EN 1040/13727 Assay Conditions for Evaluating <i>In Vitro</i>the Bactericidal Activity of a Chlorhexidine Digluconate and Benzalkonium Chloride Antiseptic Preparation

Aims: The representativeness of the mandatory bacterial strains specified in European standards for in vitro assay of the bactericidal activity of antiseptics was evaluated by testing the activity of an antiseptic combining chlorhexidine digluconate 0.2% and benzalkonium chloride 0.5% against 21 additional bacterial strains, and the positive interaction between these two biocidal agents was assessed. Methods and Results: The bactericidal activity of the antiseptic solution used pure or diluted was assessed according to the European standards EN 1040 and EN 13727. The contact time was 1 min at 20°C. Interfering substances used in the EN 13727 assay were bovine serum albumin and sheep erythrocytes, simulating “dirty” conditions, and hard water. A reduction of colony-forming units by ≥5 log10 was deemed to meet the requirements to conclude bactericidal activity. Under “basic” conditions, the bactericidal activity of the antiseptic was observed against all four mandatory strains specified in the standards as well as against nearly all the additional strains tested, including most of those with acquired antibiotic-resistance. The positive interaction between the two biocidal agents was also confirmed. Under “dirty” conditions, the bactericidal activity of the antiseptic solution was maintained against all the mandatory strains and was reduced against only four of the additional strains tested. Conclusions: With regard to the antiseptic tested and under the experimental conditions described, bactericidal activity evidenced against the mandatory strains appeared to be representative of that manifested against a wide range of the main pathogenic bacteria. Reduced bacterial activity against some of the additional strains tested (e.g. Enterobacteriaceae) was observed under “dirty” conditions. Significance and Impact of the Study: EN 13727 with some experimental adjustments represents an additional appropriate standard that needs to be considered for mucocutaneous antiseptic assessment. However, it may be worth including other specific bacterial strains to those specified in the standard, when evaluating antiseptics intended for use in certain clinical situations.

In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion,viable bacterial cell count methods,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC).Results:Methanol extract of V.negundo leaves showed potent antibacterial activity(inhibition zone:9.9-22.6 mm,MIC: 200-3 200μg/mL.MBC:200-6 400μg/mL) against all the pathogenic enteric bacteria(Vibrio cholerae.Vibrio parahemolyticus.Vibrio mimicus.Echerichia coli,Shigella spps.,and Aeromonas spps) tested.Methanol extract of V.negundo leaves showed potent bactericidal activity both in vitro laboratory conditions(MBC,200-400μg/mL) and in the intestinal environment(Dose,1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae,the major causative agent of cholera. Furthermore,assays using the mice cholera model showed that V.negundo methanol extract can protect mice from Vibrio cholerae infection and significandy decrease the mortality rate(P【0.0001). Conclusions:For the first time we showed thal medianol extract of V.negundo leaves exhibited strong vihriocidal activity both in vitro and in vivo conditions.Therefore,it will he useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

In vitro and in vivo bactericidal activity of Vitex negundo leaf extract against diverse multidrug resistant enteric bacterial pathogens

Objective:To investigate in vitro and in vivo antibacterial potentials of Vitex negundo(V. negundo) leaf extracts against diverse enteric pathogens.Methods:Water and methanol extracts of V.negundo leaves were evaluated against enteric bacterial pathogens by using standard disc diffusion,viable bacterial cell count methods,determination of minimum inhibitory concentrations(MIC) and minimum bactericidal concentrations(MBC).Results:Methanol extract of V.negundo leaves showed potent antibacterial activity(inhibition zone:9.9- 22.6 mm,MIC: 200-3 200μg/mL,MBC:200-6 400μg/mL) against all the pathogenic enleric bacteria(Vibrio cholerae,Vibrio parahaemolyticus,Vibrio mimicus,Echerichia coli.Shigella spps.,and Aeromonas spps) tested.Methanol extract of V.negundo leaves showed potent bactericidal activity both in vitro laboratory conditions(MBC,200-400μg/mL) and in the intestinal environment(Dose,1-2 mg/mL) of infant mice against pathogenic Vibrio cholerae,the major causative agent of cholera. Furthermore,assays using the mice cholera model showed that V.negundo methanol extract can protect mice from Vibrio cholerae infection and significantly decrease the mortality rate(P【0.0001).Conclusioas:For the first time we showed that methanol extract of V.negundo leaves exhibited strong vibriocidal activity both in vitro and in vivo conditions.Therefore,it will be useful to identify and isolate the active compounds of this extract that could be a good alternative of antibiotics to treat cholera.

Bactericidal and Photoeatalytie Activity of Fe^(3+)-TiO_2 Thin Films Prepared by the Sol-gel Method

Pure TiO2 thin films and iron doped TiO2 thin films on glass substrate were prepared by sol-gel method, and characterized by X-ray diffractometer （XRD）, thermo-gravimetric analysis （TG-DSC）, high resolution transmission electron microscope （HRTEM）, scanning electron microscope （SEM） and UV-Vis spectroscopy, respectively. The experimental results show that the pure TiO2 thin films and iron doped TiO2 thin films can destroy most of the escherichia coli and bacillus subtillis under the irradiation of 365 nm UV-light. However, the iron doped TiO2 thin film is a better photocatalyst than pure TiO2 thin film. The ultrastructural studies provide direct evidences for understanding the bactericidal mechanism of the TiO2 photocatalyst.

Study of the loss of bactericidal capacity of PMNs induced by bypass－activated complement

in order to verify whether the bactericidal capacity of polymorphonuclear neutrophils (PMNs)could be abolished by the bypass-activated complement,intracellular bactericidal activity (ICBA),superoxide ions (O2-) and specific granules (SGs) 3 were determine

STUDIES ON THE SYNTHESES AND BACTERICIDAL ACTIVITIES OF ACYLAMINOETHYL GLYCINES AND OF THEIR CYCLO-CONDENSATION PRODUCTS

Two series of new compounds:the aliphatic acylaminoethyl glycines (Ⅰ) and their cyclo-condensation products-allphatic acylaminoethyl plperazlnones (Ⅱ) were synthesized.The results of bactericidal and bacteriostatic tests show that the two series of compounds are good bactericldal agents.

Green synthesis of Chlorin e6 and tests of its photosensitive bactericidal activities

Phototoxic treatments of pathogenic bacteria and fungi of trees induce oxidative damage that is preferable to toxic chemical treatment.Here,we used green methods to synthesize Chlorin e6 from chlorophyll a,which was extracted from crude silkworm excrement using concentrated(strong)alkali hydrolysis and acidification.The photosensitive bactericidal activities of the new chlorin were tested in vitro,and possible mechanisms of action are discussed.The results showed that Chlorin e6 can be lightactivated to have bactericidal activity against Escherichia coli,Bacillus subtilis and Fusarium oxysporum,but it had little bactericidal effect in the dark.This kind of chlorin compounds has great potential as a natural phototoxic antimicrobial compound to control harmful bacteria on the leaves in forestry systems.

Combined antibacterial activity of stingless bee(Apis mellipodae)honey and garlic(Allium sativum)extracts against standard and clinical pathogenic bacteria

Objective:To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria.Methods:Antimicrobial activity of tazma honey,garlic and mixture of them against pathogenic bacteria were determined.Chloramphenicol and water were used as positive and negative controls,respectively.Minimum inhibitory concentration(MIC)and minimum bactericidal concentration of antimicrobial samples were determined using standard methods.Results:Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly(P≤0.05)greater than garlic and tazma honey alone.The diameter zone of inhibition ranged from(18±1)to(35±1)mm for mixture of garlic and tazma honey,(12±1)to(20±1)nun for tazma honey and(14±1)to(22±1)mm for garlic as compared with(10±1)to(30±1)mm for chloramphenicol.The combination of garlic and tazma honey(30-35 mm)was more significantly(P≤0.05)effective against Salmonella(NCTC 8385),Staphylococcus aureus(ATCC 25923),Lyesria moncytogenes(ATCC 19116)and Streptococcus pneumonia(ATCC 63).Results also showed considerable antimicrobial activity of garlic and tazma honey.MIC of mixture of garlic and tazma honey at 6.25%against total test bacteria was 88.9%.MIC of mixture of garlic and tazma honey at6.25%against Gram positive and negative were 100%and 83.33%,respectively.The bactericidal activities of garlic,tazma honey,and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25%concentration were 66.6%,55.6%and 55.6%,respectively.Conclusions:This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections.Therefore,garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections.Further in vivo study is recommended to come up with a comprehensive conclusion.

Studies on the Antibacterial Activity of the Extract of Stachytarpheta angusti folia

To investigate the scientific bases for t/te traditional use of Stachy-tarpheta angustifolia. Methods: In vitro antibacterial activity of the aqueous and ethanol extract of the plant was investigated using the agar cup plate diffusion method. Results: The ethanol extract of the plant showed antibacterial activity against Escherichia coli, Streptococcus faecalis, Shigella dysenterme, Slaphylococcus aureus (S. aureus) , Salmonella sp. , Pseudomonas aeruginosa and Neisseria gonor-r/iaeae, while the water extract was active against Escherichia coli, Streptococcus faecalis, Shigella dysenterme, Sta-phylococcus aureus and. Pseudomonas aeruginosa. The etlianol extract exhibited higher antibacterial activity than the water extract. The minimum inhibitory concentration (MIC) and minimum bactericidal, concentration (MBC} of the ethanol extract were 0. 65 mg/mt and 0. 85 mg/ml, respectively , against S. aureus. Treatment of the extract at higher temperature, 60℃ increased the sensitivity of the test organisms to the plant extract. Phytochemical analysis indicated t/tat the plant possesses tannins, saponins as well as phenols. Conclusion: A scientific basis exists that the plant possesses antibacterial activity and it could be a probable source of therapeutic agent.

Synthesis and Characterization of a New Compound of Cobalt Ⅱ with Isonicotinamide and Evaluation of the Bactericidal Potential

In this work, the isonicotinamide was coordinated to the Cobalt ion in oxidation state +2. The relevance of this work is the investigation of the in vitro bactericidal potential of the synthesized complex when tested in Gram-positive and negative bacteria strains. This study is motivated by the need to obtain new materials that have antibiotic properties and that, in the future, may become an effective drug against resistant bacteria. A new coordination compound of Cobalt and isonicotinamide, [Co(H2O)(isn)3](BF4)2, was synthesized and described. The compound was characterized by thermoanalytical techniques TG-DTG and TG-DSC, where it was possible to propose the mechanism of thermal decomposition. Through the spectroscopy in the region of the medium infrared (FTIR), it is possible to infer the site of connection between isonicotinamide and metal. The bactericidal activity of [Co(H2O)(isn)3](BF4)2, CoCl2 and free Isonicotinamide were tested for the bacteria Streptococcus mutans (Gram+) and Escherichia coli (Gram&#8722;) and the synthesized compound showed to be sensitive for both bacteria.

<i>In Vitro</i>Evaluation of Ozone Activity on Recent Clinically Isolated Bacterial Strains

This study aims to evaluate the cozone bactericidal activity in different suspension media (saline, broth and whole blood) at different exposure times. Methicillin-resistant Staphylococcus aureus, Enterococcus faecalis, ESBLpositive Escherichia coli, MDR Pseudomonas aeruginosa were suspended in different media. We used a bacterial concentration of 0.2 MF for all experiments, as this concentration is consistent with the results of septic shock blood experiments. We performed ozone insufflations in a “sealed environment”. The total number of insufflations for each experiment ranged from one to four. The gas concentration was maintained at 80 mcg/ml. We confirmed the bactericidal activity of ozone on saline for all the bacterial strains. Experiments in broth revealed no changes in the bacterial growth. Ozone is primarily bactericidal against E. coli and bacteriostatic on P. aeruginosa, S. aureus and E. faecalis on whole blood. This study confirms the bactericidal efficacy of topical ozone applications and supports the need for further evaluations of the therapeutic potential of major ozone autohemotherapy. The results in E. coli promote further investigations of ozone activity on other Enterobacteriaceae and its potential use in the treatment of urinary infections. In general, these results suggest that ozone-therapy might be an alternative therapy to overcome antibiotic resistance.

Antibacterial Activity of Honey from Wild Species of Stingless Bees;<i>Plebenia hylderbrandii</i>and <i>Meliponula bocandei</i>

One of the serious problems the world is facing today is the antimicrobial resistance on available antibiotics by most bacterial pathogens and the rising cost of finding effective antimicrobial agents. In recent years, efforts to find new drugs especially from natural sources have been boosted by the demand for an effective cure for infectious diseases. Only the antibacterial activity of apis mellifera honey and not stingless bee honey from western Kenya has been reported. This study was therefore carried out to determine the effect of Plebenia hylderbrandii and Meliponula bocandei honey samples on the growth of control;sensitive cases of Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923). Different honey concentrations (1.18% - 17.65% v/v) of the two samples were tested against the two micro-organisms. The samples were screened for their antibacterial potential against Escherichia coli and Staphylococcus aureus by agar well dilution method. The Partial inhibitory concentration (PIC), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were determined by in vitro method. The inhibitory effect of Plebenia hylderbrandii honey on E. coli and S. aureus growth was apparent at concentrations 3.53% and 1.76% (v/v) respectively. On the other hand, the inhibitory effect of Meliponula bocandei honey on S. aureus growth was at concentration 16.47% (v/v). Plebenia hylderbrandii honey had bactericidal effect on both E. coli and S. aureus at concentrations 4.71% and 2.35% (v/v) respectively. However, Meliponula bocandei honey exerted bactericidal effect on S. aureus only at 16.47% (v/v) concentration. Plebenia hylderbrandii honey had higher antibacterial potency and can be a potential source of antibacterial substances. Moreover, the honeys tested in this study showed great antibacterial potential for S. aureus.

In Vitro Antimicrobial Activity Study of Some New Arginine-based Biodegradable Poly （Ester Urethane）s and Poly （Ester Urea）s

Bactericidal activity of some arginine based biodegradable polymers-PEURs （poly （ester urethane）s） and PEUs （poly （ester urea）s） with low cytotoxicity was studied in in vitro experiments. Various bacterial strains both Gram-positive and Gram-negative were used to explore the bactericidal activity of the cationic polymers. As the test objects, the following microorganisms were used： Bacillus subtilis, Staphylococcus aureus, Mycobacterium album, Pseudomonas fluorescens, Escherichia coli, Actinomyces griseus and Aspergillus niger. The obtained results showed that the new cationic polymers suppressed the growth of the studied microorganisms and the bactericidal activity of the tested cationic polymers strongly depending on their chemical structure.

Bactericidal and Fungicidal Efficacy of Chlorine Dioxide in Various Workspaces

Previously, we demonstrated the virucidal efficacy of low concentration chlorine dioxide (ClO2) gas in room settings. The purpose of these studies was to evaluate novel ClO2 formats as potential biocidal interventions for real world congregate settings and air systems. Three types of studies were conducted to determine the efficacy of ClO2 in reducing bacteria and mold in various workspaces: hard and soft surfaces (gymnasium & equipment), aerosol (in-room), and within a laboratory environment. The study demonstrated that ClO2 was highly effective against both bacteria and mold with reduction ranging from 85.0% - > 99.4% for bacteria and >99.4% for yeast and mold. Treatments on hard and soft surfaces (gymnasiums and sports equipment), reduced bacteria by an average of 90% - 95%. The following treatments were applied overnight: 1) hard surface spraying with dilute ClO2 solutions, 2) carpet and tumbling treatments with powdered ClO2 releasing impregnates, and 3) HVAC treatment and overall room deodorization with low dose ClO2 gas from controlled releasing sachets. The in-room study treating air with a ClO2 filtration media also indicated significant air and surface room efficacy, with an average of 94% reduction in bacteria after 24-hour, and 99.4% reduction in mold after 24-hours. In a related air study, a biological combination of Raoultella terrigena and Staphylococcus aureus was injected as a bio-aerosol into a 4-inch diameter pipe with air flowing at approximately 1200 ft/min. Dry ClO2 gas was introduced into the air flow to achieve an effective concentration of 5 or 10 ppmv. Air samples were collected at sampling ports downstream from the fan at 10, 22, 55 and 100 ft along the pipe and used to evaluate changes in airborne bacteria and mold. Testing was conducted in a laboratory setting at ambient conditions. The data showed ClO2 gas reduced viable organisms at both gas concentrations, and indicated that reductions were higher for 10 ppmv concentration, and longer pipe runs. In a final study, laboratory application of gaseous chlorine dioxide was tested. Low gas release filter testing demonstrated significant surface reductions of airborne bacteria with an overall average 99.4% reduction in the 24-hour testing period. Higher gas treatments of a class II biological cabinet reduced bacillus spores on steel coupons throughout cabinet by 6 log. ClO2 was effective as a bactericidal and fungicidal treatment providing significant reduction in both surface and air. Novel product delivery forms may be useful for rapidly disinfecting air and solid surfaces in complex congregate settings.

In Vitro Anti-Bacterial and Anti-Fungal Activities of Extracts from Different Parts of 7 Zingiberaceae Plants

This study aimed to explore the anti-bacterial and anti-fungal activities of extracts from different parts of plants in the Zingiberaceae family.The inhibitory rate,minimum inhibitory concentration(MIC),and minimum bactericidal concentration(MBC)of leaf and stem,and root and rhizome extracts from Alpinia katsumadai Hayata,Alpinia oxyphylla Miq×Alpinia henryi K.Schumann,Alpinia oblongifolia Hayata,Alpinia nigra(Gaertn.)Burtt,Amomum villosum Lour,Alpinia zerumbet(Pers.)Burtt.et Smith and Alpinia oxyphylla Miq were determined using the fungus cake method and double dilution method.The seven Zingiberaceae plants exhibited characteristic antibacterial activities against pathogenic bacteria and fungi.At a 1.5 mg mL^(−1),A.zerumbet root and rhizome extracts exhibited strong inhibitory activity against S.aureus and E.coli,with 83.23%and 79.62%,respectively.In addition,A.zerumbet leaf and stem extracts had an inhibitory rate of 90.85%against P.aeruginosa.At the same concentration,the leaf and stem,root and rhizome extracts of A.katsumadai had the best anti-bacterial effect against F.oxysporum,with inhibition rates of 84.46%and 84.73%,respectively.Moreover,A.katsumadai and A.zerumbet leaf and stem extracts had the most significant antibacterial effect against S.aureus,with a MIC of 0.063 mg mL^(−1).Thus,both A.katsumadai and A.zerumbet extracts had significant antibacterial activity.In addition,by comparing the inhibitory effect of extracts from different parts,it was found that the inhibitory rate and average inhibitory rate of extracts from leaf and stem were higher than those from root and rhizome.The chemical constituents of A.katsumadai and A.zerumbet,determined by the high-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS),revealed that citric acid(CA),alpinetin,and pinocembrin(PNCB)were the functional constituents yielding the antibacterial activity.Overall,A.katsumadai and A.zerumbet have the potential to be developed as new plant fungicides and bactericides.

4种植物叶提取液对青枯雷尔氏菌抑菌活性研究

青枯雷尔氏菌Ralstonia solanacearum是一种毁灭性土传病害病原菌,防治困难,通过抑菌圈、抑菌率、最小抑菌浓度测定,探讨羊蹄甲、三裂蟛蜞菊、马缨丹、芒果叶提取液对青枯菌的抑制效果。结果表明:三裂蟛蜞菊叶提取液的抑菌效果最好,抑菌圈范围为15.00~18.13 mm,为高度敏感,在0.40 g·mL-1浓度处理下,其抑菌率达到79.63%,显著高于其他处理组;羊蹄甲和马缨丹叶提取液的抑菌圈范围为10.67~15.57 mm,为中度敏感,抑菌率分别为58.33%和60.37%;芒果叶提取液的抑菌效果最差。

Identification,Characterization,and Probiotic Potentials of Lactobacillus pentosus SF-1

In recent years probiotics have been considered as a potential substitution of antibiotics to control pathogens and treat infectious diseases in aquaculture.In the present study a strain of Lactobacillus pentosus,named as L.pentosus SF-1,was isolated from waters in aquaculture.The species identification of this strain was conducted by 16S rRNA sequence,and the physiological and biochemical characteristics of this strain were assessed.Furthermore,the virulence,antibiotic sensitivity,cell surface characteristics and acid/base-resistance of L.pentosus SF-1 were determined to evaluate the probiotic potentials of this strain.Specifically,L.pentosus SF-1 is sensitive to most common antibiotics,and no hemolysin was generated from it,indicating the safety of this strain to hosts.In addition,L.pentosus SF-1 was able to tolerate the artificial gastric juice at pH 3 for 4 h and the artificial intestinal fluid at pH 6.8 or 8.0 for 6 h.Moreover,the analysis of self-aggregation and the adhesion of L.pentosus SF-1 to organic solvents suggested a high potential of L.pentosus SF-1 to inhabit the hosts,which was confirmed by testing the colonization of L.pentosus SF-1 in germ-free zebrafish.Interestingly,L.pentosus SF-1 displayed a high bactericidal activity against several bacterial pathogens.Consistently,the incubation of L.pentosus SF-1 significantly promoted the expression of antimicrobial components in zebrafish,contributing to the protection of the fish from E.tarda infection in vivo.Taken together,the probiotic strain L.pentosus SF-1 could be applied as anti-infection reagent in aquaculture.

去氢枞酸基苯并噻唑化合物的合成及杀菌活性

为寻找具有优良生物活性的先导化合物,进一步拓展松香的使用途径,以去氢枞酸为原料,与SOCl_(2)反应制得去氢枞酸酰氯,再与2-氨基苯并噻唑化合物反应,合成6个新型去氢枞酸基2-氨基苯并噻唑化合物(4a~4f)。化合物结构经核磁共振波谱(NMR),红外光谱(IR)和高分辨质谱(HR-MS)进行了表征。采用琼脂稀释法测试了6个化合物对小麦赤霉、番茄早疫和花生褐斑等8个病菌的杀菌活性。测试结果表明:目标化合物均对供试菌具有一定的杀菌活性,对小麦赤霉杀菌活性普遍较好,其中化合物4a和4b对小麦赤霉的杀菌活性最好,分别达到66.7%和71.8%。

In Vitro Bactericidal Activity of Jinghua Weikang Capsule(荆花胃康胶丸)and Its Individual Herb Chenopodium Ambrosioides L.against Antibiotic-Resistant Helicobacter Pylori

Objective： To investigate the bactericidal effects of Jinghua Weikang Capsule （荆花胃康胶丸） and its major component Chenopodium ambrosioides L. on antibiotic-resistant Helicobacter pylori. Methods： Four 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. Results： Both 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. Conclusion： Jinghua Weikang Capsule and Chenopodium ambrosioides L. are considered to be active against antibiotic-resistant H. pylori in vitro.

Anti-Helicobacter pylori activities of Chenopodium ambrosioides L. in vitro and in vivo

AIM: To investigate the bactericidal effects of Chenopodium ambrosioides L.(CAL) against Helicobacter pylori(H.pylori) both in vitro and in vivo.METHODS: For in vitro experiments, the inhibitory activity of CAL was tested using an agar dilution method; H.pylori strain NCTC11637 was incubated on Columbia blood agar plates containing serial concentrations of CAL.The minimal inhibitory concentration(MIC) was determined by the absence of H.pylori colonies on the agar plate.Time-kill curves were used to evaluate bactericidal activity; the average number of colonies was calculated at 0, 2, 8 and 24 h after liquid incubation with concentrations of CAL at 0.5, 1, and 2 × MIC.For in vivo experiments, H.pylori-infected mice were randomly divided into CAL, triple therapy(lansoprazole, metronidazole, and clarithromycin), blank control, or H.pylori control groups.The eradication ratios were determined by positive findings from rapid urease tests(RUTs) and by histopathology.RESULTS: In vitro, the MIC of CAL against H.pylori was 16 mg/L.The time-kill curves showed a stable and persistent decreasing tendency with increasing CAL concentration, and the intensity of the bactericidal effect was proportional to dose; the 1 and 2 × MIC completely inhibited the growth of H.pylori at 24 h.In vivo, the eradication ratios in the CAL group were60%(6/10) by RUT and 50%(5/10) by histopathology.Ratios in the triple therapy group were both 70%(7/10), and there was no difference between the CAL and triple therapy groups.Histopathologic evaluation revealed massive bacterial colonization on the surface of gastric mucosa and slight infiltration of mononuclear cells after inoculation with H.pylori, but no obvious inflammation or other pathologic changes in gastric mucosa of mice from CAL and triple therapy groups.CONCLUSION: CAL demonstrates effective bactericidal activity against H.pylori both in vitro and in vivo.