Microbiota–Gut–Brain Axis: Yeast Species Isolated from Stool Samples of Children with Suspected or Diagnosed Autism Spectrum Disorders and In Vitro Susceptibility Against Nystatin and Fluconazole

Abstract

Autism spectrum disorder (ASD) is a general term for a group of complex neurodevelopmental disorders of brain development that limits a person's ability to function normally. Etiology has not been clearly defined up to date. However, gut microbiota and the bidirectional communication between the gastrointestinal tract and brain, the so-called microbiota-gut-brain axis, are hypothesized, which may be involved in the etiology of several mental disorders. Recent reports suggest that Candida, particularly Candida albicans, growth in intestines may cause lower absorption of carbohydrates and minerals and higher toxin levels which are thought to contribute autistic behaviors. The aim of this study was to identify the 3-year deposited yeasts isolated from stool samples of children with diagnosed or suspected ASD and to determine in vitro activity of nystatin and fluconazole against these isolates using Clinical Laboratory Standards Institute M27-A3 guidelines. A 17-year retrospective assessment was also done using our laboratory records. Among the species identified, intrinsically fluconazole-resistant Candida krusei (19.8 %) and Candida glabrata (14.8 %) with elevated MICs were remarkable. Overall, C. albicans (57.4 %) was the most commonly isolated species in 17 years. The species identification and/or antifungal susceptibility tests have to be performed using the strain isolated from stool sample, to select the appropriate antifungal agent, if antimycotic therapy is needed.

The Gut Microbiota and Autism Spectrum Disorders

“…krusei and Candida . glabrata were not found in healthy children (De Angelis et al, 2013; Kantarcioglu et al, 2016). Strati et al, found a significant increase in the Firmicutes / Bacteroidetes ratio in autistic subjects relative to normal subjects.…”

An approach to gut microbiota profile in children with autism spectrum disorder

“…On the other hand, Candida albicans was the most frequently identified Candida species in the work of Iovene et al (2017). In fact, some studies have pointed out that a high abundance of Candida albicans can cause less carbohydrate and mineral absorption and generate higher toxin levels that could contribute to ASD behaviours (Kantarcioglu et al, 2016). Other authors hypothesized that some Lactobacillus species can modulate the immunological responses to Candida in the GI tract by providing tryptophan-derived aryl hydrocarbon receptor ligands that stimulate the immune system, principally IL-C3 cells, to produce IL-22.…”

“…At present, the microbiota-gut-brain axis is an explanatory model that attempts to relate, among others, ASD symptoms with findings in neuroscience and bacteriology. The microbiota-gut-brain axis is defined as a bi-directional communication system between the neuronal, immune, endocrine and metabolic pathways, but it still requires better understanding (Sudo et al, 2004;Hiippala et al, 2016;Kantarcioglu et al, 2016).…”

Pregnancy complicated with agranulocytosis

“…However, her symptoms were not alleviated until the patient had a cesarean section, so we tend to believe that the pneumonia was an additional manifestation of agranulocytosis. [19] Second, due to the relatively long disease duration, the patient may have taken some drugs inducing agranulocytosis, but she could not remember, namely, the existence of information risk of bias. [20] …”