Inactivation of the oprD porin gene by a novel insertion sequence ISPa195 associated with large deletion in a carbapenem-resistant Pseudomonas aeruginosa clinical isolate

• Published in: Journal of global antimicrobial resistance. Vol. 17; pp. 309 - 311
• Main Authors: Bocharova, Yuliya, Savinova, Tatiana, Shagin, Dmitriy A., Shelenkov, Andrey A., Mayanskiy, Nikolay A., Chebotar, Igor V.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.06.2019
• Subjects: Anti-Bacterial Agents - pharmacology; Bacterial Proteins; beta-Lactamases; Carbapenem resistance; Carbapenems - pharmacology; DNA Transposable Elements - genetics; Drug Resistance, Multiple, Bacterial - genetics; Gene Components; Humans; Imipenem - pharmacology; Insertion sequence; ISPa195; Meropenem - metabolism; Microbial Sensitivity Tests; Porins - genetics; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Pseudomonas aeruginosa - genetics; Pseudomonas Infections - microbiology; Sequence Deletion; Pseudomonas aeruginosa; Carbapenem resistance; Insertion sequence; ISPa195
• ISSN: 2213-7165; 2213-7173
• DOI: 10.1016/j.jgar.2019.01.016

•New insertion sequence ISPa195 was found in oprD of carbapenem resistant Pseudomonas aeruginosa.•An IS-associated deletion was detected in oprD of ISPa195-positive isolate.•There were no direct repeats at flanking regions of ISpa195.•The oprD gene alteration was combined with carbapenem-efflux in ISPa195-positive P. aeruginosa. Alteration of the porin-encoding gene oprD by insertion sequences (ISs) is one mechanism conferring carbapenem resistance in Pseudomonas aeruginosa. Here we describe a carbapenem-resistant clinical P. aeruginosa isolate 36-989 harbouring a novel IS (ISPa195) in oprD. Minimum inhibitory concentrations (MICs) of antimicrobial agents were determined by the broth microdilution method. Carbapenemase activity was assessed using a MALDI-TOF/MS-based assay of meropenem hydrolysis. Efflux-dependent carbapenem resistance was evaluated using an assay with carbonyl cyanide 3-chlorophenylhydrazone (CCCP). The oprD gene and IS sequence were analysed by the Sanger method. Whole-genome sequencing was performed on an Illumina HiSeq 2500 platform. Antimicrobial susceptibility testing demonstrated that P. aeruginosa 36-989 was resistant to imipenem (MIC=32mg/L) and meropenem (MIC=16mg/L). No carbapenemase activity was detected, however an efflux-mediated component of carbapenem resistance was revealed. A new IS element (ISPa195) was found in the oprD gene of P. aeruginosa 36-989. ISPa195 was 1190bp in length, belonging to the IS3 family, and contained two open reading frames that overlapped through a ribosomal slippage to translate the full-size transposase enzyme. There was an IS-associated 284-bp deletion in the oprD gene; no direct repeats at flanking regions of the IS were detected. The absence of direct repeats at flanking regions in combination with the IS-associated deletion distinguished ISPa195 from other ISs previously detected in oprD. Carbapenem resistance in P. aeruginosa 36-989 was conferred by a combination of oprD alteration and carbapenem efflux.