Effect of Temperature on Metronidazole Resistance in Helicobacter pylori

Temperature - A critical abiotic paradigm that governs bacterial heterogeneity in natural ecological system

A baseline data has been presented here to prove that among the abiotic factors, temperature is the most critical factor that regulates and governs the bacterial diversity in a natural ecosystem. Present study in Yumesamdong hot springs riverine vicinity (Sikkim), parades a gamut of bacterial communities in it and hosts them from semi-frigid region (- 4-10 °C) to fervid region (50-60 °C) via an intermediate region (25-37 °C) within the same ecosystem. This is an extremely rare intriguing natural ecosystem that has no anthropogenic disturbances nor any artificial regulation of temperature. We scanned the bacterial flora through both the culture-dependent and culture-independent techniques in this naturally complex thermally graded habitat. High-throughput sequencing gave bacterial and archaeal phyla representatives of over 2000 species showcasing their biodiversity. Proteobacteria, Firmicutes, Bacteroidetes and Chloroflexi were the predominant phyla. A concave down-curve significance was found in temperature-abundance correlation as the number of microbial taxa decreased when the temperature increased from warm (35 °C) to hot (60 °C). Firmicutes showed significant linear increase from cold to hot environment whereas Proteobacteria followed the opposite trend. No significant correlation was observed for physicochemical parameters against the bacterial diversity. However, only temperature has shown significant positive correlation to the predominant phyla at their respective thermal gradients. The antibiotic resistance patterns correlated with temperature gradient where the prevalence of antibiotic resistance was higher in case of mesophiles than that of psychrophiles and there was no resistance in thermophiles. The antibiotic resistant genes obtained were solely from mesophiles as it conferred high resistance at mesophilic conditions enabling them to adapt and metabolically compete for survival. Our study concludes that the temperature is a major factor that plays a significant contribution in shaping the bacterial community structure in any thermal gradient edifice.

Susceptibility of emetic and enterotoxigenic Bacillus cereus grown at high temperature to disinfectants

The prevalence of emetic strains in food products is rare; however, infection with these may be fatal to the vulnerable population. Bacterial control of the emetic Bacillus cereus strains is still unclear. This study aimed to assess the influence of high temperature on the disinfection of emetic and enterotoxigenic B. cereus. Emetic B. cereus strains survived up to 50 °C; the lag time and maximum growth rate were higher at 42 °C than those at 30 °C. Compared to enterotoxigenic B. cereus, all emetic food strains showed higher minimum inhibitory concentrations and minimum bactericidal concentrations for sodium hypochlorite and citric acid. The disinfectant susceptibility of the emetic B. cereus OS-05 strain incubated at a higher temperature did not increase and was maintained at the highest MBC value. In all emetic B. cereus strains, enterotoxin gene expression was upregulated at 42 °C and 45 °C. Increased ces gene expression was also found in emetic B. cereus strains GP-15 and OS-05, with upregulation of 128- and 820-fold at 42 °C. Thus, emetic B. cereus grown at high temperatures may resist common disinfectants of the food industry. The findings may help control B. cereus in food or the food processing industry.

Transcriptomic and Functional Approaches Unveil the Role of tmRNA in Zinc Acetate Mediated Levofloxacin Sensitivity in Helicobacter pylori

Rapid increase in resistance of Helicobacter pylori (H. pylori) has hindered antibiotics-based eradication efforts worldwide and raises the need for additional approaches. Here, we investigate the role of zinc-based compounds in inhibiting H. pylori growth and modulating antibiotic sensitivities, interrogate their downstream transcriptomic changes, and highlight the potential mechanism driving the observed effects. We showed that zinc acetate inhibited H. pylori growth and increased H. pylori sensitivity to levofloxacin. Transcriptomic profiling showed distinct gene expression patterns between zinc acetate treated groups versus controls. In particular, we independently replicated the association between zinc acetate treatment and increased ssrA expression. Knockdown of ssrA restored levofloxacin resistance to levels of the control group. In this study, we first demonstrated the role of zinc acetate in H. pylori growth and antibiotic sensitivities. Additionally, we explored the transcriptomic perturbations of zinc acetate followed by functional knockdown follow-up of differentially expressed ssrA, highlighting the role of tmRNA and trans-translation in H. pylori levofloxacin resistance. Our results provide alternative and complementary strategies for H. pylori treatment and shed light on the underlying mechanisms driving these effects. IMPORTANCE Helicobacter pylori (H. pylori) eradication plays an important role in gastric cancer prevention, but the antimicrobial resistance of H. pylori is fast becoming a growing concern. In this study, we investigated the role of zinc acetate in inhibiting H. pylori growth and modulating antibiotic sensitivities in vitro. Additionally, we explored the transcriptomic perturbations of zinc acetate followed by functional knockdown follow-up of differentially expressed ssrA, highlighting the role of tmRNA and trans-translation in H. pylori levofloxacin resistance. Our results open up a new horizon for the treatment of antibiotic-resistant H. pylori.

Effect and Safety of Helicobacter pylori Eradication Treatment Based on Molecular Pathologic Antibiotic Resistance in Chinese Elderly People

Background

The elderly people generally have poor tolerance to drugs and an increased risk of adverse effects. Our study was designed to determine the effect and safety of Helicobacter pylori (H. pylori) eradication treatment based on molecular pathologic antibiotic resistance in Chinese elderly people over the age of 60 years.

Methods

A total of 364 people were retrospectively analyzed, including 113 older people over 60 and 251 young and middle-aged people in the age of 20–59 years. Real-time PCR detection and conventional PCR and sequencing method were used for drug susceptibility testing. As the main outcome measure, the eradication rates (ERs) with their 95% confidence intervals (CIs) were analyzed by intention to treat (ITT) and per protocol (PP). For the safety of therapy, adverse events were analyzed.

Results

For the total people, the resistance rates to clarithromycin (CLR), amoxicillin (AMX), fluoroquinolone (FLQ) and tetracycline (TET) were 65.06%, 7.54%, 61.39% and 20.37%, respectively. After they were divided into two groups, the resistance rates were 62.39% (CLR), 9.09% (AMX), 69.64% (FLQ) and 22.45% (TET) in the 113 older people over 60, and 66.26%, 6.85%, 57.66% and 19.47% in the 251 young and middle-aged people in 20–59. By the ITT analysis, the ERs were 92.04% (95% CI, 86.97–97.10%, n=113) in the older people and 92.43% (95% CI, 89.14–95.73%, n=251) in the young and middle-aged people. By the PP analysis, the ERs were 96.30% (95% CI, 92.68–99.92%, n=108) and 94.69% (95% CI, 91.87–97.52%, n=245), respectively. No significant differences were shown both in the ITT analysis (P=0.896) and in the PP analysis (P=0.517). The three most common adverse events were black stool, dysgeusia and diarrhea, and no serious adverse event was reported.

Conclusion

H. pylori eradication treatment based on molecular pathologic antibiotic resistance showed good effect and safety in Chinese elderly people.

Biomarker Characterization and Prediction of Virulence and Antibiotic Resistance from Helicobacter pylori Next Generation Sequencing Data

The Gram-negative bacterium Helicobacter pylori colonizes c.a. 50% of human stomachs worldwide and is the major risk factor for gastric adenocarcinoma. Its high genetic variability makes it difficult to identify biomarkers of early stages of infection that can reliably predict its outcome. Moreover, the increasing antibiotic resistance found in H. pylori defies therapy, constituting a major human health problem. Here, we review H. pylori virulence factors and genes involved in antibiotic resistance, as well as the technologies currently used for their detection. Furthermore, we show that next generation sequencing may lead to faster characterization of virulence factors and prediction of the antibiotic resistance profile, thus contributing to personalized treatment and management of H. pylori-associated infections. With this new approach, more and permanent data will be generated at a lower cost, opening the future to new applications for H. pylori biomarker identification and antibiotic resistance prediction.