Candida spp. are commensal organisms of the skin, mucous membranes, gastrointestinal tract, blood, and vagina of animals and humans. In recent decades, the incidence of human fungal infections has increased, with Candida spp. (mainly C. albicans) infections being the most frequent, and the treatment of fungal infections is still a clinical challenge. Colonization of the human gastrointestinal tract by Candida spp. is significant because infections (e.g., candidemia and vulvovaginal candidiasis) frequently arise from commensal microorganisms. The aim of this study was to test in vitro the antifungal activity and the eventual synergistic effect of five pure components of essential oils: cinnamaldehyde, α-pinene, limonene, eucalyptol, and eugenol. These compounds were tested on 18 Candida strains (15 C. albicans, 2 C. glabrata, and 1 C. lusitaniae) derived from a culture collection of vaginal clinical strains. Methods: Fungistatic activity was evaluated using the disk diffusion method. For fungicidal activity, microdilution and time–kill curve protocols were set up. The checkerboard method was chosen to evaluate a possible synergistic effect of these compounds when mixed. Results: Cinnamaldehyde and eugenol gave the best results, inhibiting all the Candida strains and showing a highly additive effect (FICI 0.625). The cinnamaldehyde inhibition zone (IZ), MIC, and MFC means were 69 mm, 50.05 mg/L, and 109.26 mg/L respectively. Cinnamaldehyde led to the total loss of viable Candida cells within 4 h. Eugenol IZ, MIC, and MFC means were 35.2 mm, 455.42 mg/L, and 690.09 mg/L, respectively. Eugenol led to the total loss of viable fungal cells within 1 h. Treatment with α-pinene inhibited 88.9% of Candida strains, with an IZ mean of 21.2 mm, a MIC mean of 195.41 mg/L, and a MFC mean of 251.27 mg/L; this compound led to the total loss of viable fungal cells only after 24 h. Limonene inhibited only 33.3% of the tested strains and eucalyptol did not produce an inhibition halo, so these compounds were not tested further. Conclusions: These characteristics, together with the well-known safety of cinnamaldehyde and eugenol for human use, make these two natural compounds the perfect candidates for the treatment of candidiasis. This was a pilot study, the purpose of which was to evaluate the best composition of a mixture to be used against intestinal and vulvovaginal candidiasis; in vivo studies are needed to confirm these very encouraging results.

Background and aims: Only a few antimicrobials are effective against H. pylori, and antibiotic resistance is an increasing problem for eradication therapies. In 2017, the World Health Organization categorized clarithromycin resistant H. pylori as a “high-priority” bacterium. Standard antimicrobial susceptibility testing can be used to prescribe appropriate therapies but is currently recommended only after the second therapeutic failure. H. pylori is, in fact, a “fastidious” microorganism; culture methods are time-consuming and technically challenging. The advent of molecular biology techniques has enabled the identification of molecular mechanisms underlying the observed phenotypic resistance to antibiotics in H. pylori. The aim of this literature review is to summarize the results of original articles published in the last ten years, regarding the use of Next Generation Sequencing, in particular of the whole genome, to predict the antibiotic resistance in H. pylori.Methods: a literature research was made on PubMed. The research was focused on II and III generation sequencing of the whole H. pylori genome. Results: Next Generation Sequencing enabled the detection of novel, rare and complex resistance mechanisms. The prediction of resistance to clarithromycin, levofloxacin and amoxicillin is accurate; for other antimicrobials, such as metronidazole, rifabutin and tetracycline, potential genetic determinants of the resistant status need further investigation.

Treatment of Helicobacter pylori (H. pylori) infection is a challenge for clinicians. The large increase in drug-resistant strains makes the formulation of new therapeutic strategies fundamental. The frequent onset of side effects during antibiotic treatment (mainly due to intestinal dysbiosis) should not be underestimated as it may cause the interruption of treatment, failure of H. pylori eradication and clonal selection of resistant bacteria. Probiotic integration during antibiotic treatment can exert a dual function: a direct antagonistic effect on H. pylori and a balancing effect on dysbiosis. Therefore, it fulfills the definition of a new therapeutic strategy to successfully treat H. pylori infection. Data reported in literature give promising but discrepant results. Aim: To assess in vitro bacteriostatic and bactericidal activity of probiotic strains against H. pylori. Materials and methods: L. casei, L. paracasei, L. acidophilus, B. lactis and S. thermophilus strains were used. Agar well diffusion and time-kill curves were carried out to detect bacteriostatic and bactericidal activity, respectively. Results: All probiotic strains showed both bacteriostatic and bactericidal activity vs. H. pylori. Conclusions: Such findings prompted us to plan a protocol of treatment in which probiotics are given to infected patients in association with antibiotic therapy.

Background and aims: the increasing prevalence of strains resistant to antimicrobial agents is a critical issue for the management of Helicobacter pylori infection. This study aimed to evaluate, in Italian naïve patients, H. pylori antibiotic resistance trends and their potential predictive factors during the last decade. Methods: consecutive Italian naïve H. pylori positive patients, referred from General Practitioners to our Unit from January 2009 to January 2019 to perform an upper gastrointestinal endoscopy (UGIE), were considered. Each patient underwent ¹³C-urea breath test (¹³C-UBT) and UGIE with multiple biopsies to perform rapid urease test (RUT), culture/susceptibility test (vs. clarithromycin, metronidazole, levofloxacin), and histopathological examination. H. pylori status was assessed through CRM (composite reference method: at least two tests positive or only culture positive). Results: between 2009 and 2014, 1763 patients were diagnosed as H. pylori positive, 907 were naïve with antibiogram available. Between 2015 and 2019, 1415 patients were diagnosed as H. pylori positive, antibiotic susceptibility test was available in 739 naïve patients. H. pylori primary antibiotic resistance rates in the first and second five-year period were, respectively, clarithromycin 30.2% (95% CI 27.2–33.3), 37.8% (95% CI 34.2–41.4); metronidazole 33.3% (95% CI 30.2–36.5), 33.6% (95% CI 30.2–37.1); levofloxacin 25.6% (95% CI 22.8–28.5), 33.8% (95% CI 37.4–47.4), double resistance clarithromycin-metronidazole 18.9% (95% CI 16.4–21.6), 20.7% (95% CI 17.8–23.8). The increase of the resistance rates to clarithromycin and levofloxacin in naïve patients was statistically significant (p < 0.05). Although eradication rates for sequential therapy in the 10 years considered were 93.4% (95% CI 92–94.6) and 87.5% (95% CI 85.7–89) at per-protocol (PP) and intention-to-treat (ITT) analysis, respectively, they showed a significant decrease in the second five-year period. Conclusions: this data highlights an increase in primary H. pylori antibiotic resistance and strongly suggests the importance of drug susceptibility testing also in naïve patients.

Background and aims: Italian guideline suggests 10-day sequential or bismuth-based quadruple therapies for first-line Helicobacter pylori treatment. Comparison between these regimens is lacking. We assessed the efficacy of these therapies in clinical practice and evaluated the role of primary bacterial resistance toward clarithromycin and metronidazole. Patients and methods: Consecutive patients with H. pylori infection were enrolled. Bacterial culture with antibiotics susceptibility testing was attempted in all cases. Patients received either a sequential therapy with esomeprazole 40 mg for 10 days plus amoxicillin 1000 mg for the first 5 days followed by clarithromycin 500 mg and tinidazole 500 mg (all twice daily) for the remaining 5 days, or bismuth-based therapy with esomeprazole 20 mg twice daily and Pylera 3 tablets four times daily for 10 days. H. pylori eradication was assessed by using ¹³C-urea breath test. Results: A total of 495 patients were enrolled. Following sequential (250 patients) and quadruple (245 patients) therapies, the eradication rate were 92 and 91%, respectively, at intention-to-treat analysis and 96 and 97%, respectively, at per protocol analysis. Overall, the pattern of bacterial resistance did not significantly affect the cure rate, but the presence of clarithromycin and metronidazole dual resistance tended to reduce the success rate of both sequential (84.8 vs. 90.1%; P=0.4) and quadruple (85 vs. 94.1%; P=0.06) therapies. Adverse events occurred more frequently with the quadruple than with sequential therapy (56.9 vs. 25.8%; P<0.001). Conclusion: In our country, sequential and bismuth-based quadruple therapy achieved similarly high eradication rates as first-line treatments for H. pylori infection in clinical practice.

Antimicrobial resistance to clarithromycin and metronidazole significantly affects the cure rate of standard therapies for Helicobacter pylori infection. We tested whether different MIC levels of resistance to these antibiotics play a role in therapeutic efficacy. This was a post hoc analysis of data from a therapeutic trial in which patients with antibiotic susceptibility testing (Etest) received first-line sequential therapy. The level of antibiotic resistance was classified according to MIC values into low (MIC from >0.5 to ≤8 for clarithromycin, and from >8 to ≤32 for metronidazole) and high (MIC from >8 to 256 mg/L for clarithromycin, and from >32 to 256 mg/L for metronidazole). Data from 1006 patients were included. There were 520 (51.7%) patients with susceptible strains, 136 (13.5%) with clarithromycin-resistant strains, 144 (14.3%) with metronidazole-resistant strains and 206 (20.5%) with clarithromycin-resistant and metronidazole-resistant strains. In the presence of double resistance, the cure rate was still high (38/41, 92.7%) when MIC levels were low and it was reduced (94/112, 83.9%) only when MIC levels of both antibiotics were high. The cure rates did not significantly differ between patients with single antibiotic-resistant strains, irrespective of MIC values, and those with susceptible strains. We found that MIC levels of resistance to either clarithromycin or metronidazole play a role in H. pylori therapy outcome and that bacterial resistance becomes relevant in vivo when clarithromycin-resistant and metronidazole-resistant strains have high MIC values for at least one of these antibiotics.