Multilocus sequence typing of Ochrobactrum spp. isolated from gastric niche

Area of Science:

• Microbiology
• Gastric Pathogen Research
• Bacterial Genetics

Background:

• The human stomach harbors diverse bacterial communities, including non-Helicobacter pylori species.
• Ochrobactrum species have been identified in the gastric niche, with prior reports of co-occurrence with H. pylori.
• Limited information exists on the genetic diversity of Ochrobactrum in the stomach.

Purpose of the Study:

• To investigate the species distribution and genetic diversity of Ochrobactrum spp. in the human gastric niche.
• To analyze Ochrobactrum diversity in relation to the presence or absence of Helicobacter pylori.
• To explore geographical variations in Ochrobactrum species within India.

Main Methods:

• Molecular identification and multilocus sequence typing (MLST) of 62 Ochrobactrum isolates from gastric biopsies.
• Detection of H. pylori DNA in biopsies using molecular methods.
• Phylogenetic analysis to determine Ochrobactrum species groups.
• Antibiotyping using colistin and polymyxin B for species differentiation.

Main Results:

• Ochrobactrum isolates were phylogenetically classified into O. intermedium, O. anthropi, and O. oryzae groups.
• Multiple Ochrobactrum species were found in the gastric niche, irrespective of H. pylori presence.
• Some urease-positive biopsies contained Ochrobactrum without detectable H. pylori DNA.
• Antibiotyping differentiated O. intermedium and O. anthropi but did not reveal resistance-driven diversity.

Conclusions:

• The human gastric niche is populated by diverse Ochrobactrum species, independent of H. pylori.
• Further research is crucial to understand the commensal or pathogenic roles of these non-H. pylori bacteria.
• Evaluation should consider geographical distribution, lifestyle, and nutritional factors influencing Ochrobactrum.