Effect of carbapenems on the transcriptional expression of the oprD, oprM and oprN genes in Pseudomonas aeruginosa

• Published in: Journal of medical microbiology Vol. 53; no. 9; pp. 915 - 920
• Main Authors: Kolayli, Fetiye, Karadenizli, Aynur, Savli, Hakan, Ergen, Kivanc, Hatirnaz, Ozden, Balikci, Erdener, Budak, Fatma, Vahaboglu, Haluk
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01-09-2004; Society for General Microbiology
• Subjects: Anti-Bacterial Agents - pharmacology; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - metabolism; Bacteriology; Biological and medical sciences; Drug Resistance, Bacterial; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial; Humans; Imipenem - pharmacology; Infectious diseases; Medical sciences; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Meropenem; Microbial Sensitivity Tests; Microbiology; Miscellaneous; Polymerase Chain Reaction; Porins - genetics; Porins - metabolism; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - genetics; Pseudomonas aeruginosa - metabolism; RNA, Messenger - genetics; RNA, Messenger - metabolism; Thienamycins - pharmacology; Transcription, Genetic - drug effects; Pseudomonadales; Bacteria; Pseudomonadaceae; Pseudomonas aeruginosa; Gene; Microbiology
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.45692-0

1–3,5 Mikrobiyoloji ve Klinik Mikrobiyoloji AD 1 , Tibbi Biyoloji AD 2 , Biyofizik AD 3 and Enfeksiyon Hastaliklari & Klinik Mikrobiyoloji AD 5 , KOU Tip Fakultesi, Sopali Ciftligi, 41900 Derince Kocaeli, Turkey 4 IU, Deneysel Tip Arastirma Enstitusu, Istanbul, Turkey
Correspondence Haluk Vahaboglu vahabo{at}hotmail.com
Received April 7, 2004
Accepted May 27, 2004
The effects of imipenem and meropenem on the transcriptional expression of resistance-related genes oprD , oprM and oprN in Pseudomonas aeruginosa were studied by quantitative real-time PCR. Four strains were examined: the type strain PT5 (PAO1), its derivatives M7 and PT149, and a clinical isolate, PaKT3. The derivative M7 is a nalB mutant, overexpressing the MexAB–OprM pump, and the derivative PT149 is a nfx C-type mutant, overexpressing the MexEF–OprN pump while it is down-regulated for the OprD protein. After 18 h incubation in broth, the cultures were divided into three portions. Two were supplemented with antibiotics and the other was left antibiotic-free as the control. After a further 45 min incubation, total RNA was isolated from the strains by guanidine denaturation and acid-phenol/chloroform extraction. DNA-free total RNAs were immediately reverse-transcribed by MMuLV reverse transcriptase. Concentrations of mRNAs obtained by quantitative PCR were expressed relative to uninduced portions of the strains. The results showed that oprD was relatively stable against carbapenem antibiotics. oprM was induced significantly by imipenem in only one strain and oprN was induced by imipenem in most of the strains. The responses at the mRNA level found here were unexpected and suggested a chaotic, unpredictable regulatory mechanism.