Antibiotic resistance among Helicobacter pylori strains is the major cause of eradication failure. Resistance prevalence is dynamic and can greatly vary among countries over the years. We revealed H. pylori resistance trends for five antibiotics in 14 countries through articles predominantly published in 2018–2022, since the latest data can best show the most recent trends in resistance evolution. Amoxicillin resistance generally exhibited no evolution, yet it increased in Bulgaria, Iran, China, and Vietnam. Metronidazole resistance exhibited different trends, including an increase, a decrease and no evolution in six, three, and five studies, respectively. Clarithromycin resistance increased in Australia, Belgium, Bulgaria, Italy, Iran, and Taiwan, but remained stable in France, Spain, Russia, China, Chile, and Colombia. Tetracycline resistance was low and stable except in Iran. Levofloxacin resistance increased in four European and six other countries/regions, without significant increases in France, Spain, and Chile. In Chile, triple resistance also increased. In countries such as France and Spain, resistance to most antibiotics was stabilized, while in Bulgaria, Belgium, Iran and Taiwan, resistance to three or more agents was reported. Use of non-recommended regimens, national antibiotic consumption, patient’s compliance, host factors, strain virulence, migrations, and azithromycin overuse during the COVID-19 pandemic can influence resistance evolution. New drugs, eradication regimens and diagnostic methods, such as next-generation sequencing can improve H. pylori infection control.

Updating data on Clostridioides difficile antibiotic resistance is important for treatment improvement of C. difficile infections (CDIs). Results from 20 countries were included. The mean resistance to 2 mg/l vancomycin, 2 mg/l metronidazole, 4 mg/l moxifloxacin, and 4 mg/l clindamycin was 4.7% (0 to ≥ 26% in two studies), 2.6% (0 to ≥ 40% in 3 studies), 34.9% (6.6->80%), and 61.0% (30->90%), respectively. Resistance to erythromycin (>60-88%), rifampin (>23-55.0%), imipenem (0.6 to > 78% in a clone), tigecycline (0-<5.0%), and fidaxomicin (0-2%) was also found. Resistance to ≥ 5 antibiotics of different classes was reported in some countries. High resistance and multidrug resistance were observed in hypervirulent and epidemic strains. Although only 1% of COVID-19 patients had CDIs, the proportion might be underestimated. C. difficile antimicrobial susceptibility varied by country/region, study period, and circulating ribotypes. For CDI treatment, fidaxomicin (preferably) or vancomycin is recommended, while metronidazole is suitable for mild infections. New approaches, including biotherapeutics (Rebyota), strains, antibiotics (ridinilazole and ibezapolstat), and monoclonal antibodies/cocktails merit further evaluation. Because of the resistance rate variations, C. difficile antibiotic susceptibility should be regularly monitored. Post-COVID-19 resistance should be separately presented. Some discrepancies between vancomycin and metronidazole results need to be clarified.

Since 2010, there have been relatively scanty reports on Clostridioides (Clostridium) difficile asymptomatic colonization in children, especially in those aged >2 years. We evaluated asymptomatic C. difficile carriage in children according to literature data since 2010 and added our results for 61 asymptomatic Bulgarian children aged 2–17 years. Data analysis indicated that carriage is usually the most frequent in the youngest children aged ≤2 years, thereafter decreasing with intestinal microbiota establishment. However, the colonization rates are highly variable, ranging from 0–10% to 30–80%, according to the country, age group and underlying diseases and other concurrent conditions. In our study on older children (mean age, 6.9 years), the colonization rate was 6.6% and no toxigenic C. difficile were found. Among the reviewed reports, in many studies, toxigenic C. difficile carriage was low (0–13%), but much higher (15->54%) in children with inflammatory bowel disease (IBD) and oncological diseases. Binary positive carriage was rare or absent. The risk factors for C. difficile colonization included younger age, dysbiosis, present/recent hospitalization during previous 3 months, present/previous antibiotic or proton pump inhibitor use, underlying diseases such as IBD or oncological diseases as well as environmental contamination and tube feeding. Contamination control and breast feeding were protective factors. Probiotic plus prebiotic use and dietary changes may be beneficial. Briefly, since C. difficile carriage may be a potential source of infections, regular monitoring of colonization, especially of the toxigenic C. difficile is necessary to assess risks of clinically expressed diseases.

The COVID-19 pandemic boosted antibiotic use in Bulgaria. The aim of the study was to evaluate for the first time in our country, the influence of the COVID-19 pandemic on both characteristic, prevalence and antibiotic susceptibility of Clostridioides difficile. We investigated 75 C. difficile strains isolated since the pandemic compared with 52 strains from 2013–2019. In 2020–2023, the toxigenic strains (TCDs) were 92.0% of all strains vs. 57.7% of those isolated beforehand. In 2020–2023, TCD resistance was metronidazole 5.8%, vancomycin 1.4%, and fidaxomicin 1.6%, without significant differences between the two periods. We observed a 5.5-fold increase in the prevalence of hypervirulent (HCD) strains. In HCD strains in 2020–2023, metronidazole resistance was 7.9%. Notably, resistance to levofloxacin 1 and 32 mg/l was 91.9% and 75.8%, respectively, in TCD strains from 2020–2023. Briefly, the increase in both TCD and HCD strains and the presence of resistance to all three antibiotics for treating C. difficile infections imply the need for susceptibility testing of all TCD isolates. The strikingly high levofloxacin resistance was linked to fluoroquinolone consumption in Bulgaria. The results stress the need for regular monitoring of antibiotic susceptibility of TCD strains, and strict adherence to the antibiotic policy.

The aim of the study was to evaluate the activity of three cranberry (Vaccinium macrocarpon) ethanol solutions on Helicobacter pylori growth and urease activity. We included numerous clinical Helicobacter pylori isolates and three methods: agar well diffusion method (AWDM), disk diffusion method (DDM) and urease inhibition test (UIT). The results were expressed as differences in inhibitory zone diameters (AWDM and DDM) or urease inhibition duration (UIT) by cranberry solutions compared to the ethanol control. AWDM showed that 400, 40 and 4 mg/l cranberry extracts inhibited the growth of 82.1, 57.1 and 42.8% of the isolates, respectively, while DDM at the highest cranberry concentration suppressed only 39.3% of the isolates. At 400, 40 and 4 mg/l, cranberry extracts also inhibited urease activity of 63.6, 54.5 and 40.9% isolates within 10 min, but of fewer isolates (18.2, 13.6 and 9.1%, respectively) at the 45th min. Although cranberry activity was dose- and strain-dependent, it affected more than half of the isolates at the two highest concentrations. DDM was less effective in detecting this activity. The cranberry extracts also inhibited the urease activity of H. pylori; however, in most cases, the inhibition was only temporary. Briefly, the high cranberry activity against H. pylori, together with its anti-adhesive, antioxidant, anti-biofilm and anti-cancer properties, justifies its use for prophylaxis or adjunctive treatment of chronic H. pylori infection. Importantly, UIT results suggest the benefit of regular cranberry intake over random intake.