Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Horvath, L.
Changes of the Microbiome in Critically Ill Patients
Humanmedizin; [ Diplomarbeit ] Graz Medical University; 2018. pp.
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- Autor*innen der Med Uni Graz:
- Betreuer*innen:
- Hoegenauer Christoph
- Krause Robert
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- Abstract:
- Background. The human microbiome of multiple body sites is supposed to be affected by critical illness and clinical interventions. When and how microbes change in intensive care unit (ICU) patients is not fully understood. Methods. This pilot study investigated the short and long-term changes of microbiota composition in the pharynx, feces, tracheobronchial and gastric secretion of 6 ICU patients. The association of clinical factors (medication, infections, mechanical ventilation) was studied for each case. The microbiota of clinical samples was phylogenetically characterized by 16S rRNA sequencing. All samples were divided into 3 groups (early, mid, late), depending on sampling day after ICU admission. Results and Discussion. Overall, the microbiome of both respiratory and gastrointestinal tract showed a clear loss of species-richness over the course of hospitalisation (seen by decreasing Chao1 indices). Low-diversity communities (one genus comprising over 75%) were detected in all patients, especially in pharyngeal, tracheobronchial and gastric samples, the majority after longer ICU stays. Microbial composition showed great interpatient differences, but Staphylococcus and Enterococcus were pathogens frequently observed in several patients. We found that patients with an infection showed the infecting pathogen in at least one sample before (3 of 5 patients) or after (all patients) the clinical diagnosis of the infection. In most of these cases, the same pathogen was detected simultaneously in multiple sample areas, suggesting colonization of different body habitats by dominant pathogens. Concerning other clinical factors, intense antibiotic therapies seem to have a big impact on changes in microbiota composition. Assessing the clinical influence of microbiota diversity-loss in relation to the abundance of nosocomial pathogens in critically ill patients is of great interest for the future.