Molecular characterization and amplified ribosomal DNA restriction analysis of entomopathogenic bacteria associated with Rhabditis (Oscheius) spp.

Bacterial strains associated with entomopathogenic nematodes (EPNs) Rhabditis (Oscheius) spp. were isolated from infected cadavers of Galleria mellonella. The obtained 18 isolates were subdivided into nine phylogenetically different genera based on comparative sequence analysis of their 16S rRNA genes. The isolates were affiliated to three different class namely γ-proteobacteria (Enterobacter, Proteus, Providencia, Pseudomonas, Stenotrophomonas), β-proteobacteria (Alcaligenes) and Bacilli (Bacillus, Enterococcus, Lysinibacillus). It was observed that Gram-positive strains (Bacilli) were more frequently associated with the EPN, whereas Gram-negative isolates were affiliated to six different genera with more genotypic diversity. Subsequently, all bacterial isolates used in this study were analyzed by amplified ribosomal DNA restriction analysis (ARDRA). Eight restriction endonucleases (CfoI, HinfI, RsaI, DdeI, Sau3AI, AluI, HaeIII, and MspI) were examined and a total of 15 different genotypes were obtained, forming two heterogenous main clusters after analysis by un-weighted pair-group method using arithmetic averages.