Authors: Kawther Aabed , Nadine Moubayed , Abrar Motlak , Al-Anoud Al-Rasheed , Ameerah Al-Otaibi , Aisha Al-Asmri , Hanadi Abu-Dusha

Abstract

Background and Objective: Human gut harbors a diverse community of more than 100 trillion microbial cells that play an important role in human metabolism, physiology, immune function, and nutrition. Similarly, disruptions to the composition of this population can be linked with gastrointestinal conditions,such as obesity and inflammatory bowel disease. The aim of the present study was to compare the microbial community characteristics among obese, normal-weight and post-gastric bariatric surgerypatients.
Methods: Fifteen healthy adults, who were classified into (1) normal-weight (n=5) (2) obese (n=5) according to their Body mass index (BMI) and (3) post-bariatric surgery (n=5) groups. Gut microbiota from fecal samples were profiled by the streak plate method and theconstituent populationswere identified by biochemical analysis (Vitek2). Finally, specific bacterial strains were identified via molecular techniques, such as Polymerase chain reaction (PCR). Moreover, the antimicrobial sensitivity of E. coli strains isolated from healthy adults was evaluated to determine the pathogenic strains.
Results: The findings revealed that gut microbiota diversity increased following bariatric surgery, whereby84.6% of increased bacteria belonged to Proteobacteria, especially Escherichia coli (member of Gammaproteobacteria). The main bacterial groups in individuals that underwent bariatric surgery were Gemella morbillorum, Citrobacter freundii, Serratia odorifera, Proteus mirabilis, Enterococcus gallinarum, Klebsiella pneumonia, Enterobacter cloacae complex, Pseudomonas aeruginosa and Escherichia coli. The main bacterial groups in the normal-weight group were Citrobacter freundii, Serratia marcescens, Proteus
mirabilis and Escherichia coli. Finally, in obese individuals, Enterobacter cloacae complex, Klebsiella pneumonia, Enterococcus gallinarum and Escherichia coli were the main bacterial groups.Conclusion: These results indicate that inducing changes in the gut microbiota may be a relevant therapeutic approach for obesity and other metabolic defects.

Keywords: Human, Gut microbiota, Obesity, Normal-weight, Bariatric surgery, Adults