Variations in IS6 promoters alter the expression of carbapenem resistance in related strains of Acinetobacter baumannii. Issue 1 (March 2015)

• Record Type: Journal Article
• Authors: Al-Hassan, Leena; Opazo, Andres; Lopes, Bruno S.; Mahallawy, Hadir El; Amyes, Sebastian G.B.
• Is Part Of: Journal of global antimicrobial resistance. Volume 3:Issue 1(2015:Mar.)
• Page Start: 5
• Page End: 8
• Publication Date: 2015-03
• Subjects: Acinetobacter baumannii -- blaOXA-58 -- Carbapenem resistance -- Genetic environment -- Insertion sequences -- IS6 family; Drug resistance -- Periodicals; Drug resistance -- Periodicals; Drug resistance; Periodicals; 616.9041
• DOI: 10.1016/j.jgar.2014.10.003
• Languages: English
• ISSNs: 2213-7165

Abstract

Highlights: We examined the genetic environment of the bla OXA-58 gene in Acinetobacter baumannii from Egypt. The upstream IS Aba3 was interrupted by IS 1008 and IS 1006 in two clonal isolates. IS 6 family elements are effective promoters for the expression of bla OXA-58 . Hybrid promoters confer higher minimum inhibitory concentrations to carbapenems. The genetic plasticity of A. baumannii and insertion sequences contribute to carbapenem resistance. Abstract: The aim of this work was to investigate the role of the IS 6 family of insertion sequences present upstream of bla OXA-58 in two clonally related carbapenem-resistant Acinetobacter baumannii isolates obtained from paediatric cancer patients in Egypt. To determine their relatedness, the isolates were typed by pulsed-field gel electrophoresis (PFGE), and the intrinsic bla OXA-51-like gene was amplified and sequenced. Minimum inhibitory concentrations (MICs) to imipenem and meropenem was determined according to British Society of Antimicrobial Chemotherapy (BSAC) guidelines. PCR and sequencing of bla OXA-58 and the upstream and downstream regions was performed to determine the genetic environment. The two isolates were positive for the intrinsic bla OXA-64 gene, and the MICs for isolates AB-14298 and AB-P67 were 8 mg/L and 64 mg/L for imipenem and 2 mg/L and 16 mg/L for meropenem, respectively. The bla OXA-58 gene in AB-14298 was flanked by IS Aba3 interrupted with IS 1006, whereas AB-P67 had IS Aba3 interrupted by IS 1008, both belonging to the IS 6 family of insertion sequences. In conclusion, both IS 1006 and IS 1008 provided suitable promoter sequences for expression of the downstream bla OXA-58 gene.