title: Association of the Exotoxin A and Exoenzyme S with Antimicrobial Resistance in Pseudomonas Aeruginosa Strains.
abstract: BACKGROUND
  Pseudomonas aeruginosa is a gram-negative and opportunistic bacterium that causes opportunistic infections in immunosuppressed patients. The main purpose of this study was to investigate the association between exotoxin A and exoenzyme S production with antibiotic resistance patterns.
  
  
  METHODS
  The toxA and exoS genes were detected in 102 clinical isolates by PCR. Antibiotic susceptibility tests were performed by disk diffusion method (Kirby Bauer). The Chi-square and Fisher's test were used for evaluation of the association between "toxins and infections source" and "toxins and antibiotic resistance" respectively.
  
  
  RESULTS
  Frequency of toxA+ and exoS+ strains was 81% and 61%, respectively. The association between drug resistance and toxA+ genotype was significant for all antibiotics tested (P < 0.05) except aztreonam; however, no significant association was observed between drug resistance and exoS gene (P > 0.05).
  
  
  CONCLUSIONS
  High frequency of toxA+ resistant strains isolated from inpatients and significant association between the toxin and drug resistance in more antibiotics, reinforces possible role of exotoxin A as an extracellular protein in the regulation of drug resistance genes. The results may be further verified by Southern blot analysis of toxA and exoS gene expression and elucidation of the mechanism of antibiotic resistance.
authors.affiliation: Microbiology Department, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Nour
authors.initials: N
authors.lastname: Amirmozafari
authors.affiliation: Department of Biology, School of Basic Science, University of Qom, Qom, Iran.
authors.forename: Jalil
authors.initials: J
authors.lastname: Fallah Mehrabadi
authors.affiliation: Department of Biology, Faculty of Sciences, Islamic Azad University, Rasht Branch, Rasht, Iran. Alirh110@gmail.com.
authors.forename: Alireza
authors.initials: A
authors.lastname: Habibi
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics*; D000900:Anti-Bacterial Agents / Q000032:analysis*; D001427:Bacterial Toxins / Q000235:genetics*; D001769:Blood / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005098:Exotoxins / Q000235:genetics*; D005798:Genes, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000302:isolation & purification; D014132:Trachea / Q000382:microbiology; D014556:Urine / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics*; D014947:Wounds and Injuries / Q000382:microbiology; D000097668:Pseudomonas aeruginosa Exotoxin A
chemical_list: D036002:ADP Ribose Transferases; D000900:Anti-Bacterial Agents; D001427:Bacterial Toxins; D005098:Exotoxins; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A; C444820:exoenzyme S