title: [Clinical significance of virulence-related genes of type III secretion system of Pseudomonas aeruginosa].
abstract: OBJECTIVE
  To study the clinical significance of virulence genes exo U and exo S of type III secretion system (TTSS) of Pseudomonas aeruginosa (PA).
  
  
  METHODS
  One hundred and eighty-nine clinical isolates of PA were collected from five hospitals. The incidence of virulence genes exo U and exo S in PA were determined with PCR. Minimum inhibitory concentration of anti-bacterial drug for PA was determined with microdilution method. The clinical features and outcomes of 60 hospitalized patients colonized or infected with exo U+/exo S- positive or exo U-/exo S+ positive PA isolated from sputum were analyzed retrospectively. Data were processed with chi-square test.
  
  
  RESULTS
  Among the 189 PA isolates, 85.2% (161/189) harbored TTSS genes, including exo U-/exo S+ type (120 isolates), exo U+/exo S- type (31 isolates), exo U-/exo S- type (7 isolates), and exo U+/exo S+ type (3 isolates). 72.0% (72/100) isolates from sputum and 81.5% (44/54) isolates from blood belonged to exo U-/exo S+ genotype. Compared with those of TTSS-negative isolates, the antimicrobial resistance of TTSS-positive isolates to cefoperazone/sulbactam, ceftazidime, amikacin, and cefepime were lower (with χ² value respectively 10.1, 16.1, 9.3, 33.8, P values all below 0.01). The antimicrobial resistance to all examined drug between exo U-/exo S+ type and exo U+/exo S- type isolates was close (with χ² values from 0.08 to 2.04, P values all above 0.05). Patients detected with exo U+/exo S- positive PA isolated from sputum were significantly associated with PA infection, and they usually had history of tracheal intubation, ICU hospitalization, and combined use of drugs for anti-infection treatment. Patients detected with exo U-/exo S+ positive PA isolated from sputum were significantly associated with PA colonization, which had basic lung disease and better outcome than the former infection type.
  
  
  CONCLUSIONS
  The TTSS exists in most clinical isolates of PA. Detection of exo U or exo S of PA isolated from sputum is helpful for the analysis of clinical features and outcome of patients.
authors.affiliation: State Key Laboratory of Respiratory Diseases, the First Affiliated Hospital of Guangzhou Medical College, Guangzhou 510230, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Zhuo
authors.forename: Lu-xia
authors.initials: LX
authors.lastname: Wang
authors.forename: Shu-nian
authors.initials: SN
authors.lastname: Xiao
authors.forename: Hong-yu
authors.initials: HY
authors.lastname: Li
authors.forename: Gui-xia
authors.initials: GX
authors.lastname: Qiu
authors.forename: Nan-shan
authors.initials: NS
authors.lastname: Zhong
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D058947:Bacterial Secretion Systems / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D005798:Genes, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D012189:Retrospective Studies; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D001427:Bacterial Toxins; C111749:pseudomonas exoprotein A protein, Pseudomonas aeruginosa; D036002:ADP Ribose Transferases; C444820:exoenzyme S