Evaluation of oprI and oprL genes as molecular markers for the genus Pseudomonas and their use in studying the biodiversity of a small Belgian River

A multiplex PCR based on oprI and oprL, coding for the outer membrane lipoprotein I and the peptidoglycan-associated lipoprotein OprL, respectively, was developed for the detection of Pseudomonas strains from a bacterial collection isolated from a small river. To study the diversity of these Pseudomonas isolates, an oprI-oprL gene sequence database of 94 Pseudomonas type strains was constructed. Phylogenetic analysis of the concatenated oprI and oprL gene sequences of the Pseudomonas type strains showed that they were largely congruent with the classification based on the MLSA approach based on 16S rRNA, gyrB, rpoB and rpoD gene sequences of Mulet et al. in 2010.

Identification of the isolates demonstrated a high diversity of Pseudomonas isolates at the source of the river located in a forest of which most isolates belonged to the Pseudomonas fluorescens lineage. On the other hand, the Pseudomonas population isolated at an anthropized site at the mouth of the river, receiving waste water from both households and industry, was very different and contained many Pseudomonas aeruginosa isolates.