Effect of Temperature on Metronidazole Resistance in Helicobacter pylori

Abstract

Efficacy of Helicobacter pylori (H. pylori) eradication therapy has declined due to rapid rises in antibiotic resistance. We investigated how increased temperature affected H. pylori (NCTC 11637) growth and its sensitivity to metronidazole in vitro. We performed transcriptomic profiling using RNA-sequencing to identify differentially expressed genes (DEGs) associated with increased temperature. Transcriptional pathways involved in temperature-driven metronidazole resistance changes were analyzed through bioinformatic and literature curation approaches. We showed that H. pylori growth was inhibited at 41°C and inhibition was more apparent with prolonged incubation. Resistance to metronidazole was also reduced—minimum inhibitory concentration for metronidazole decreased from > 256 μg/ml at 37°C to 8 μg/ml at 41°C after culturing for 3 days. RNA-sequencing results, which were highly concordant within treatment conditions, revealed more than one third of genes (583/1,552) to be differentially expressed at increased temperatures with similar proportions up and down-regulated. Quantitative real-time PCR validation for 8 out of 10 DEGs tested gave consistent direction in gene expression changes. We found enrichment for redox and oxygen radical pathways, highlighting a mechanistic pathway driving temperature-related metronidazole resistance. Independent literature review of published genes associated with metronidazole resistance revealed 46 gene candidates, 21 of which showed differential expression and 7 out of 9 DEGs associated with “redox” resistance pathways. Sanger sequencing did not detect any changes in genetic sequences for known resistance genes rdxA, frxA nor fdxB. Our findings suggest that temperature increase can inhibit the growth and reduce H. pylori resistance to metronidazole. Redox pathways are possible potential drivers in metronidazole resistance change induced by temperature. Our study provides insight into potential novel approaches in treating antibiotic resistant H. pylori.

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

“… 1 , 8 The increasing prevalence of antibiotic resistance is our main concern in treatment of H. pylori infection, which can lead to significant eradication failure. 9 , 10 In China, the resistance rates to clarithromycin, metronidazole, and levofloxacin, are already high. One study from Nanjing showed that the H. pylori resistance rates to clarithromycin, levofloxacin and metronidazole were 47.03%, 33.59% and 80.76%, respectively.…”

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

“…This is one of the first studies to examine the transcriptomic perturbations associated with zinc acetate treatment, which showed distinct gene expression profiles compared to controls. Widespread transcriptomic perturbations were also previously seen after changes in environmental conditions such as temperature ( 17 , 18 ). This suggests significant transcriptomic changes occur in H. pylori in response to biophysical as well as chemical perturbations.…”

Helicobacter pylori Antibiotic Resistance: Molecular Basis and Diagnostic Methods

“…Mutations in the rdxA gene encoding oxygen-insensitive nitroreductase and in the frxA gene encoding flavin oxidase reductase are the main cause of resistance to metronidazole. Mutations in these genes reduce the ability of metronidazole to recover to active forms (NO 2− , NO 2 2− ), which have a damaging effect on the bacterial DNA structure [14,15]. Levofloxacin is a fluoroquinolone, which acts via its interaction with DNA gyrase encoded by the gyrA and gyrB genes.…”