Candida albicans infection delays duodenal ulcer healing in cysteamine-induced duodenal ulcers in rats

Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results

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.

A rare case report of fungal esophagitis combined with giant gastric ulcer in an immunocompetent patient

RATIONALE

Fungal infection of gastrointestinal (GI) tract is usually seen in immunocompromised patients, but can rarely occur in immunocompetent people in whom no permissive factor is present.

PATIENT CONCERNS

We describe a 68-year-old male immunocompetent patient presenting with simultaneous fungal esophagitis and giant gastric ulcer.

DIAGNOSES

Repeated endoscopic biopsies were taken from the giant gastric ulcer edge and base and histology demonstrated granulation tissue and pseudohyphal fungal forms.

INTERVENTIONS

The patient was treated with fluconazole and omeprazole for 8 weeks.

OUTCOMES

After antifungal treatment with fluconazole, the patient's clinical symptoms gradually disappeared with the healing of gastric ulcer, which never recurred in this patient until 3 months after follow-up.

LESSONS

Nonhealing gastroesophageal ulcers highlights the importance of repeated endoscopies and biopsies.

Disruption of the intestinal mucosal barrier in Candida albicans infections

Candida albicans is a common microorganism in the intestine. However, invasive C. albicans infection has emerged as a life-threatening disease in recent years. The mortality rate of invasive candidiasis is high in critically ill hosts. C. albicans can switch from the yeast to the hyphal morphology, and take advantage of the impaired intestinal mucosal barrier and insufficient immunity of the host to facilitate its colonization and penetration. Despite the availability of potent new antifungal drugs in recent years, the treatment of severe candidiasis, especially candidaemia, has not been substantially improved. In this review, the virulence factors of C. albicans, as well as the antagonistic role of the intestinal mucosal barrier will be discussed to illuminate the mechanisms of C. albicans enterogenic infections.

Giant fungal gastric ulcer in an immunocompetent individual

Candida infection of gastrointestinal tract is frequent in immunocompromised patients and rare in an otherwise healthy person in whom no permissive factor is present. Herein is a case report on 25-year-old woman, 2 months postpartum, with fungal gastric ulcer with invasion leading to fungemia. She developed fever and anemia. Gastric biopsy and blood culture both showed growth of Candida albicans. The patient responded well to parenteral amphotericin B. This supports the hypothesis of invasion of Candida from gastric ulcer into blood.

Inflammation and gastrointestinal Candida colonization

Candida organisms commonly colonize the human gastrointestinal tract as a component of the resident microbiota. Their presence is generally benign. Recent studies, however, show that high level Candida colonization is associated with several diseases of the gastrointestinal tract. Further, results from animal models argue that Candida colonization delays healing of inflammatory lesions and that inflammation promotes colonization. These effects may create a vicious cycle in which low-level inflammation promotes fungal colonization and fungal colonization promotes further inflammation. Both inflammatory bowel disease and gastrointestinal Candida colonization are associated with elevated levels of the pro-inflammatory cytokine IL-17. Therefore, effects on IL-17 levels may underlie the ability of Candida colonization to enhance inflammation. Because Candida is a frequent colonizer, these effects have the potential to impact many people.