Molecular characteristics of P. aeruginosa isolated from human sources and cow milk.

摘要

One hundred ten human ear, eye, wound and burn swabs and 153 cow milk samples were tested for P. aeruginosa isolates. Samples were streaked on blood and MacConkey agar and suspected colonies sub-cultured on chromogenic and cetrimide media. Isolates were identified according to colony morphology, gram staining, conventional biochemical reactions and analytical profile index 20E (API 20E). PCR assay confirmed presence of P. aeruginosa and nucleotide sequence of isolates. We found P. aeruginosa in 11.4%(30/263), with 21.8% (24/110) from human samples and 3.9% (6/153) from cow milk. PCR with species specific 16SrRNA gene (956 bp) verified that 100% isolates were P. aeruginosa and identified P2 and P5 from humans and P27 and P30 from cow milk with 100%identity for P2, P5, P30 but 99% for P27. Evolutionary taxa for local Iraqi and global P. aeruginosa species taken from NCBI database provided an optimal tree of 11 nucleotide sequences matching isolates P2, P5 and P30 with global isolates but differentwith P27. Results suggest PCR and sequence analysis confirmed P.aeruginosa strain differences between humans and cow milk.