title: Comparison of antibiotic resistance and virulence factors in pigmented and non-pigmented Pseudomonas aeruginosa.
abstract: OBJECTIVE
  Pseudomonas aeruginosa produces multiple virulence factors that have been implicated in pathogenesis and quorum sensing. The aim of this study was to determine differences in the virulence factors of pigmented and non-pigmented P aeruginosa isolates.
  
  
  METHODS
  Associations were assessed between pigment production (pyocyanin and pyoverdin) and production of DNase, elastase, lipase, protease, siderophore, twitching motility, antibiotic resistance patterns and virulence-associated genes in 57 non-duplicate P aeruginosa isolates from wounds, sputum, urine, high vaginal swab (HVS), ear, eye and respiratory tract swabs and aspirates of peritoneum and ulcers.
  
  
  RESULTS
  Most (82.5%) of the isolates produced either pigment. Pigmented isolates produced more frequently and significant more (p < 0.05) DNase, elastase, lipase protease, and siderophore. Imipenem was the only antibiotic to which all isolates were susceptible (p < 0.05), while 93% and 32% were resistant to tetracycline and norfloxacin, respectively. There was however no significant difference between pigmented and non-pigmented isolates when antibiotic resistance was compared. While isolates had multiple virulence-associated genes, exoS (51%), rhlA (37%) and rhlB (46%) were the predominant genes detected. Except for exoY, genes were present in pigmented isolates more frequently than in non-pigmented isolates.
  
  
  CONCLUSIONS
  The results of this study suggest that antibiotic resistance per se might not be associated with the pigment production in P aeruginosa. However pigment production appeared to be more significantly associated with multi-drug resistance, presence of virulence-associated genes, and expression of certain virulence factors, most notably elastase, protease, siderophore and DNase activity. Since pigment production is easy to determine, this might to be a good starting point to identify the virulence status of an isolate.
authors.affiliation: Department of Basic Medical Sciences, Biochemistry Section, The University of the West Indies, Kingston 7, Jamaica, West Indies.
authors.forename: E A
authors.initials: EA
authors.lastname: Finlayson
authors.forename: P D
authors.initials: PD
authors.lastname: Brown
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D016009:Chi-Square Distribution; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D009643:Norfloxacin / Q000494:pharmacology*; D009842:Oligopeptides / Q000378:metabolism; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011550:Pseudomonas aeruginosa / Q000302:isolation & purification / Q000378:metabolism* / Q000472:pathogenicity*; D011710:Pyocyanine / Q000378:metabolism; D013752:Tetracycline / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D009842:Oligopeptides; C042453:pyoverdin; D011710:Pyocyanine; D036002:ADP Ribose Transferases; C444820:exoenzyme S; D013752:Tetracycline; D009643:Norfloxacin