Micro-broth dilution method with air-dried microplate for determining MICs of clarithromycin and amoxycillin for Helicobacter pylori isolates

CRISPR-like sequences association with antibiotic resistance and biofilm formation in Helicobacter pylori clinical isolates

Role of clustered regularly interspaced short palindromic repeats (CRISPR)-like sequences in antibiotic resistance and biofilm formation isn't clear. This study investigated association of CRISPR-like sequences with antibiotic resistance and biofilm formation in H. pylori isolates. Thirty-six of H. pylori isolates were studied for existence of CRISPR-like sequences using PCR method and their correlation with biofilm formation and antibiotic resistance. Microtiter-plate technique was utilized for investigating antibiotic resistance profile of isolates against amoxicillin, tetracycline, metronidazole and clarithromycin. Biofilm formation of isolates was analyzed by microtiter-plate-based-method. Out of 23 CRISPR-like positive isolates, 19 had ability of biofilm formation and 7 of 13 CRISPR-like negative isolates were able to form biofilm (Pvalue = 0.445). In CRISPR-like positive isolates, 11 (48%), 18 (78%), 18 (78%) and 23 (100%) were resistant to amoxicillin, tetracycline, metronidazole and clarithromycin, respectively. Since CRISPR-like sequences have role in antibiotic resistance, may be applied as genetic markers of antibiotic resistance. But there was no substantial correlation between biofilm formation and existence of CRISPR-like sequences. These results indicate possible importance of CRISPR-like sequences on acquisition of resistance to antibiotics in this bacterium.

Impact of body size on first-line Helicobacter pylori eradication success using vonoprazan and amoxicillin dual therapy

BACKGROUND

As a first-line therapy for Helicobacter pylori, dual therapy with vonoprazan and amoxicillin (VA-dual) provides an eradication rate similar to that of vonoprazan-based triple therapy. As the factors associated with the eradication rate of H. pylori with VA-dual are unknown,we investigated them in this study.

MATERIALS AND METHODS

Overall, 163 patients diagnosed with H. pylori infection received VA-dual (vonoprazan 20 mg twice daily and amoxicillin 750 mg twice daily for 7 d). The association between successful H. pylori eradication and the following patient clinical factors was analyzed: sex, age, height, weight, body surface area (BSA), body mass index (BMI), history of early gastric carcinoma and peptic ulcer, comorbidity of cirrhosis, alcohol consumption habit, smoking habit, common use of proton pump inhibitors, and concomitant use of drugs that are substratesof cytochrome P450 (CYP) 3A4. The association between post-eradication adverse events and clinical factors was analyzed retrospectively.

RESULTS

Successful H. pylori eradication was associated with a lower BSA (eradication rate: 90.8% in patients with BSA <1.723 vs. 79.6% in those with BSA ≥1.723; p = 0.045). The incidence of adverse events was higher in women than in men (adverse events: 40.0% in women vs. 19.4% in men; p = 0.004).

CONCLUSIONS

Successful H. pylori eradication with VA-dual was associated with the small body size of patients. This therapy may have to be adjusted per body size.

Total alkaloids of Sophora alopecuroides- and matrine-induced reactive oxygen species impair biofilm formation of Staphylococcus epidermidis and increase bacterial susceptibility to ciprofloxacin

Objective

To investigate the mechanism by which total alkaloids of Sophora alopecuroides (TASA) and matrine (MT) impair biofilm to increase the susceptibility of Staphylococcus epidermidis (S. epidermidis) to ciprofloxacin.

Methods

The minimum biofilm inhibitory concentration (mBIC) was determined using a 2-fold dilution method. Structure of biofilm of S. epidermidis was examined by Confocal Laser Scanning Microscope (CLSM). The cellular reactive oxygen species (ROS) was determined using a DCFH-DA assay. The key factors related to the regulation of ROS were accessed using respective kits.

Results

TASA and MT were more beneficial to impair biofilm of S. epidermidis than ciprofloxacin (CIP) (P < 0.05). TASA and MT were not easily developed resistance to biofilm-producing S. epidermidis. The mBIC of CIP decreased by 2–6-fold following the treatment of sub-biofilm inhibitory concentration (sub-BIC) TASA and MT, whereas the mBIC of CIP increased by 2-fold following a treatment of sub-BIC CIP from the first to sixth generations. TASA and MT can improve the production of ROS in biofilm-producing S. epidermidis. The ROS content was decreased 23%−33% following the treatment of sub-mBIC CIP, whereas ROS content increased 7%−24% following treatment with TASA + CIP and MT + CIP combination from the first to sixth generations. Nitric oxide (NO) as a ROS, which was consistent with the previously confirmed relationship between ROS and drug resistance. Related regulatory factors-superoxide dismutase (SOD) and glutathione peroxidase (GSH) could synergistically maintain the redox balance in vivo.

Conclusion

TASA and MT enhanced reactive oxygen species to restore the susceptibility of S. epidermidis to ciprofloxacin.

The synergy of resveratrol and alcohol against Helicobacter pylori and underlying anti-Helicobacter pylori mechanism of resveratrol

AIMS

To determine individual antibacterial and synergistic antibacterial effects of resveratrol and alcohol against Helicobacter pylori 26695 in vitro, and to elucidate the underlying mechanism of action of resveratrol against H. pylori.

METHODS AND RESULTS

The minimum inhibitory concentrations (MICs) and time-killing curve of resveratrol and alcohol were determined. Transcriptome analysis by RNA sequencing was used to elucidate the underlying mechanism of action of resveratrol against H. pylori. Our results showed that the MICs of resveratrol and alcohol against H. pylori 26695 are about 64 μg ml^-1 and 4% (v/v) respectively. The synergy was found: resveratrol at concentration of 64 μg ml^-1 in combination with alcohol at concentration of 4% (v/v) showed >10 000-fold decrease in the mount of viable bacteria compared with resveratrol and alcohol used alone. Transcriptome analysis showed 152 genes were downregulated and 111 genes were upregulated in the presence of resveratrol. Genes involved in protein translation (17·1%), outer membrane proteins (OMPs) (9·9%) and transports (11·2%) comprise 38·2% of the downregulated genes. In comparison, genes involved in redox (13·5%), pathogenesis and motility (9·9%) and iron homeostasis (4·5%) comprise 27·9% of the upregulated genes.

CONCLUSIONS

The synergy of resveratrol and alcohol against H. pylori was found in this study. The underlying mechanism of action of resveratrol against H. pylori may be mainly attributed to its inhibitory effect on translation, OMPs, transports, ATP synthase and possible oxidative damage.

SIGNIFICANCE AND IMPACT OF THIS STUDY

Our study provides a global insight into the anti-H. pylori mechanism of resveratrol. Both resveratrol and alcohol can contribute to inhibition of ribosomes, changes in OMPs and oxidative damage, which may be the explanations of synergistic effect against H. pylori elicited by resveratrol and alcohol.

Antimicrobial resistance and characteristics of eradication therapy of Helicobacter pylori in Japan: a multi-generational comparison

BACKGROUND

Eradication of Helicobacter pylori (H. pylori) at a younger age is considered to be effective in preventing gastric cancer. This study assessed the characteristics of eradication therapy in young patients.

MATERIALS AND METHODS

We enrolled 1073 patients with H. pylori infection between 2000 and 2013. The subjects were divided into three groups according to age into the young (≤30 years), middle-aged (31-50 years), and elder (≥51 years) groups. We also examined 472 cases to investigate clinical eradication characteristics.

RESULTS

The rate of clarithromycin (CAM) resistance was 57.9%, 34.5%, and 35.2% in the young, middle-aged, and elder group, respectively, in 2012-2013 and was significantly higher in the young group than in the elder group (p = .01). Metronidazole (MNZ) resistance was similar among the three groups at each time point. While CAM resistance rose over the study period, MNZ resistance was noted to have decreased of late. The overall initial eradication success rate was 91.9% (95% CI, 89.1-94.1) in our cohort. Eradication efficiency was comparable in the young, middle-aged, and elder group at 94.3% (95% CI, 87.4-97.5), 90.2% (95% CI, 82.9-94.6), and 91.8% (95% CI, 88.1-94.5) respectively. Side effects such as skin rash were observed in 14.8%, 3.9%, and 3.5% of the respective groups. There were significant differences in the incidence of side effects between the young group and other groups (p < .05, respectively).

CONCLUSION

Since CAM resistance and the incidence of side effects are higher in young individuals, it is especially important to select eradication regimens based on testing for antimicrobial susceptibility.

In vitro anti-Helicobacter pylori activity of a flavonoid rich extract of Glycyrrhiza glabra and its probable mechanisms of action

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza glabra Linn. is regarded useful for peptic ulcer in traditional systems of medicine in India and Helicobacter pylori has been considered as one of the causative factors for peptic ulcer. Aim of the present study is to evaluate the anti-Helicobacter pylori action of GutGard(®), a flavonoid rich extract of Glycyrrhiza glabra and further to elucidate the possible mechanisms of its anti-Helicobacter pylori action.

MATERIALS AND METHODS

Agar dilution and microbroth dilution methods were used to determine the minimum inhibitory concentration of GutGard(®) against Helicobacter pylori. Protein synthesis, DNA gyrase, dihydrofolate reductase assays and anti-adhesion assay in human gastric mucosal cell line were performed to understand the mechanisms of anti-Helicobacter pylori activity of GutGard(®).

RESULTS

GutGard(®) exhibited anti-Helicobacter pylori activity in both agar dilution and microbroth dilution methods. Glabridin, the major flavonoid present in GutGard(®) exhibited superior activity against Helicobacter pylori while glycyrrhizin did not show activity even at 250 μg/ml concentration. In protein synthesis assay, GutGard(®) showed a significant time dependent inhibition as witnessed by the reduction in (35)S methionine incorporation into Helicobacter pylori ATCC 700392 strain. Additionally, GutGard(®) showed a potent inhibitory effect on DNA gyrase and dihydrofolate reductase with IC(50) value of 4.40 μg/ml and 3.33 μg/ml respectively. However, the extract did not show significant inhibition on the adhesion of Helicobacter pylori to human gastric mucosal cell line at the tested concentrations.

CONCLUSION

The present study shows that, GutGard(®) acts against Helicobacter pylori possibly by inhibiting protein synthesis, DNA gyrase and dihydrofolate reductase.

Total alkaloids from Sophora alopecuroides L. increase susceptibility of extended-spectrum β-lactamases producing Escherichia coli isolates to cefotaxime and ceftazidime

OBJECTIVE

To evaluate the antimicrobial activity of total alkaloids extracted from Sophorea alopecuroides L. (TASA) against clinical isolated extended-spectrum beta-lactamases (ESBLs) producing Escherichia coli (E. coli) strains.

METHODS

The antibacterial activity of TASA either itself or in combination with cefotaxime (CTX) or ceftazidime (CAZ) was investigated by using the microbroth dilution method and phenotypic confirmatory disk diffusion test against three clinical isolated ESBLs-producing E. coli strains; the interactions of TASA and CTX or CAZ were ascertained by evaluating the fractional inhibitory concentration index (FICI).

RESULTS

The antibacterial activity of either TASA itself or in combination with CTX or CAZ was found. The minimum inhibitory concentration (MICs) of TASA against the ESBLs producing isolates was 12.5 mg/mL. In the combinations with a sub-inhibitory concentration of TASA, a synergistic effect on CTX and CAZ against the ESBLs producing isolates was observed. Similarly, the isolates exposed to lower dose of TASA yielded an increased susceptibility to CTX and CAZ by 8-16 folds determined by microdilution assay. Moreover, enzymatic detection of ESBLs demonstrated that TASA induced reversal resistance to CTX and CAZ partially by a mechanism of inhibition of ESBLs activity in these isolates. Additionally, in the tested isolates following the exposure of TASA, molecular analysis verified the SHV-type beta-lactamase encoding ESBL gene in these isolates, and no mutation was introduced into the ESBL gene.

CONCLUSIONS

These results suggest that TASA could be used as a source of natural compound with pharmacological activity of reversal resistance to antimicrobial agent. These findings also indicated that the application of the TASA in combination with antibiotics might prove useful in the control and treatment of infectious diseases caused by the ESBLs producing enterobacteriaceae.

Total alkaloids of Sophorea alopecuroides-induced down-regulation of AcrAB-TolC efflux pump reverses susceptibility to ciprofloxacin in clinical multidrug resistant Escherichia coli isolates

In this report, total alkaloids extracted from the seeds of Sophorea alopecuroides (TASA) was evaluated against clinical Escherichia coli isolates resistant to four tested antibiotics, ampicillin (AM), amikacin (AN), cefotaxime (CTX) and ciprofloxacin (CIP). The TASA showed an antibacterial activity against the multidrug resistant (MDR) isolates. In combination with TASA, synergistic effects on the tested antibiotics against the MRD isolates were observed. Similarly, the isolates pretreated with a lower dose of TASA yielded increased and stable susceptibilities to CIP by 16-32-fold determined by a microbroth dilution checkerboard method. Moreover, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis revealed a constitutive overexpression of the AcrAB-TolC pump system in the tested MDR isolates. The pretreatment of MDR isolates with TASA resulted in a statistically down-regulated expression of acrA and acrB genes, and an up-regulated expression of acrR gene (p < 0.05). But the expression of tolC gene was not significantly altered (p > 0.05). These results suggested that the TASA-induced reversal resistance to CIP might be partially through a mechanism of inhibition of the AcrAB-TolC pump activity in these isolates, implying that the TASA can be used as a potential natural source to develop efflux pump inhibitors (EPI) against AcrAB-TolC pump mediated MDR in E. coli isolates.