Molecular Detection of Metallo-β-Lactamase and Putative Virulence Genes in Environmental Isolates of Pseudomonas Species

摘要

The aim of this study was to investigate the presence of metallo-β-lactamase (Imp-1, Vim-1, Vim-2) -resistant genes and putative virulence genes (ExoS, Apr, LasB, PhzM) in some environmental isolates of Pseudomonas species recovered from freshwater, wastewater, cultivated soil, plant root, and plant rhizosphere samples. Polymerase chain reaction (PCR) was employed to evaluate the presence and established metallo-P-lactamase and virulence genes using specific primer sets. About 6.7% of the Pseudomonas isolates from wastewater treatment plant were found to harbour the cytotoxin gene, while 20%, 20.6%, and 6.7% of the isolates were positive for alkaline protease, phenazine and Vim-2 genes, respectively. For the Pseudomonas species isolated from plant rhizosphere, 14.3% were positive for phenazine gene, while 10.7% were positive for Vim-2 gene. Dissemination of the target genes were in the following pattern: all isolates that harboured ExoS, Apr, and Vim-2 genes from wastewater sample were found to be Pseudomonas putida, while phenazine gene was found in 75% of Pseudomonas putida isolates and 25% of other Pseudomonas species. All plant rhizosphere isolates harbouring phenazine and Vim-2 genes were observed to be Pseudomonas putida species. The incidence of Vim-2 and virulence genes in some environmental isolates of Pseudomonas species suggest that these isolates are reservoirs of metallo-β-lactamase-resistant genes and are potential pathogens that may be of serious public health significance.