A potential role of aminoglycoside resistance in endemic occurrence of Pseudomonas aeruginosa strains in lower airways of mechanically ventilated patients

Diagn Microbiol Infect Dis. 2014 Jan;78(1):79-84. doi: 10.1016/j.diagmicrobio.2013.09.015. Epub 2013 Oct 7.

Abstract

Altogether, 98 Pseudomonas aeruginosa isolates from a 5-bed intensive care unit were fingerprinted with pulsed-field gel electrophoresis and tested for aminoglycoside resistance genes aac(6')-Ib, aac(3″)-IIa, ant(2″)-Ia, armA, rmtA, and rmtB and integrons and virulence genes/operons phzI, phzII, phzM, phzS, apr, lasB, plcH, plcN, pilA, algD, toxA, exoS, exoT, exoY, and exoU. Two major clusters were identified (49 and 19 isolates), harbouring aac(6')-Ib, blaPSE-1, and ant(3″)-Ia genes or ant(2″)-Ia gene, respectively, on a class I integron. Most virulence genes except for exoU and pilA were found. Only 1 isolate of the minor cluster (8 isolates) and 1 of the 22 sporadic isolates carried integrons (without gene cassettes); virulence profile was highly variable. Comparing the resistance and virulence patterns of endemic and sporadic isolates suggests that integron-borne aminoglycoside resistance is more closely associated with the frequency than virulence. Consequently, aminoglycoside usage may have played a role in maintenance of the endemic clones.

Keywords: Amikacin; Gene cassette; Integron; Pulsed-field gel electrophoresis; Virulence factors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aminoglycosides / pharmacology*
  • Bacterial Proteins / genetics
  • DNA Fingerprinting
  • DNA, Bacterial / genetics
  • Drug Resistance, Bacterial*
  • Drug Utilization
  • Electrophoresis, Gel, Pulsed-Field
  • Female
  • Humans
  • Male
  • Middle Aged
  • Polymerase Chain Reaction
  • Pseudomonas aeruginosa / classification
  • Pseudomonas aeruginosa / drug effects
  • Pseudomonas aeruginosa / genetics
  • Pseudomonas aeruginosa / isolation & purification*
  • Respiration, Artificial / adverse effects*
  • Respiratory System / microbiology*
  • Virulence Factors / genetics
  • Young Adult

Substances

  • Aminoglycosides
  • Bacterial Proteins
  • DNA, Bacterial
  • Virulence Factors