Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance
profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and
water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from inpatients
in different hospitals in France. One of the isolated strains (HB3267) kills insects and is resistant to the majority of
the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein
enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics,
macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To
shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome
of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both
chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic
and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens.
The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading
antibiotic resistant determinants to new hosts.