Inhibitory Effects of Carvacrol on Biofilm Formation in Colistin Heteroresistant Acinetobacter baumannii Clinical Isolates.

BACKGROUND: The ability of bacteria to form biofilm is an essential strategy for creating stable infections. This issue is more critical in Acinetobacter bauamannii as a hospital pathogen. Today, the control of biofilm formation and solutions to prevent or remove biofilm is being developed. Carvacrol has been considered an anti-biofilm compound in significant bacteria. This study investigated the anti-biofilm effect of Carvacrol on biofilm formation in clinical colistin heteroresistant isolates of A. baumannii. METHODS: 22 clinical strains of A. baumannii were collected from Motahari Hospital in Tehran, Iran, in 2019. Biochemical and genotypic methods confirmed these isolates. Colistin heteroresistance was determined by the Standard PAP method. Carvacrol's antibacterial and anti-biofilm activity was determined according to the standard protocol. RESULTS: About 12 isolates were considered strong biofilm producers and were used for analysis. Six isolates had hetero-resistance to colistin. Carvacrol at a 512 g/ml concentration showed the best antibacterial activity against all isolates. The sub-MIC of Carvacrol (256 g/ml) reduced the biofilm formation capacity, which was statistically significant (p < 0.05). CONCLUSION: The results of this study showed that sub-MIC of Carvacrol has anti-biofilm effects in clinical A.baumannii colistin hetero-resistance isolates.

The global prevalence of gastric cancer in Helicobacter pylori-infected individuals: a systematic review and meta-analysis.

BACKGROUND: Helicobacter pylori is a gastrointestinal pathogen that infects around half of the world's population. H. pylori infection is the most severe known risk factor for gastric cancer (GC), which is the second highest cause of cancer-related deaths globally. We conducted a systematic review and meta-analysis to assess the global prevalence of GC in H. pylori-infected individuals. METHODS: We performed a systematic search of the PubMed, Web of Science, and Embase databases for studies of the prevalence of GC in H. pylori-infected individuals published from 1 January 2011 to 20 April 2021. Metaprop package were used to calculate the pooled prevalence with 95% confidence interval. Random-effects model was applied to estimate the pooled prevalence. We also quantified it with the I2 index. Based on the Higgins classification approach, I2 values above 0.7 were determined as high heterogeneity. RESULTS: Among 17,438 reports screened, we assessed 1053 full-text articles for eligibility; 149 were included in the final analysis, comprising data from 32 countries. The highest and lowest prevalence was observed in America (pooled prevalence: 18.06%; 95% CI: 16.48 - 19.63; I2: 98.84%) and Africa (pooled prevalence: 9.52%; 95% CI: 5.92 - 13.12; I2: 88.39%). Among individual countries, Japan had the highest pooled prevalence of GC in H. pylori positive patients (Prevalence: 90.90%:95% CI: 83.61-95.14), whereas Sweden had the lowest prevalence (Prevalence: 0.07%; 95% CI: 0.06-0.09). The highest and lowest prevalence was observed in prospective case series (pooled prevalence: 23.13%; 95% CI: 20.41 - 25.85; I2: 97.70%) and retrospective cohort (pooled prevalence: 1.17%; 95% CI: 0.55 - 1.78; I 2: 0.10%). CONCLUSIONS: H. pylori infection in GC patients varied between regions in this systematic review and meta-analysis. We observed that large amounts of GCs in developed countries are associated with H. pylori. Using these data, regional initiatives can be taken to prevent and eradicate H. pylori worldwide, thus reducing its complications.