OBJECTIVES: Three clinical Acinetobacter baumannii isolates (A-C) were isolated from three separate patients during an outbreak in a hospital in Krakow, Poland. Isolate A was recovered first and was susceptible to carbapenems, whereas isolates B and C were resistant. The aim of this study was to investigate the differences in carbapenem susceptibility in these outbreak-related isolates. METHODS: Clonal relatedness was determined using rep-PCR-based DiversiLab. The bla(OXA-51-like) genes and their upstream regions were sequenced. Expression of the genes encoding OXA-51-like and the three major porins CarO, OprD-like and 33-36 kDa Omp were investigated by semi-quantitative RT-PCR. Comparison of outer membrane protein (OMP) profiles was performed using SDS-PAGE. ISAba1-bla(OXA-82) was cloned into the shuttle vector pWH1266 and transferred into A. baumannii ATCC 17978. RESULTS: The isolates were identical by rep-PCR and clustered with international clonal lineage 2. Sequencing of bla(OXA-51-like) revealed a conversion of OXA-66 (isolate A) into OXA-82 (isolates B and C). bla(OXA-82) was also associated with ISAba1. Expression analysis revealed overexpression of bla(OXA-82). There was no difference in OMP expression between the isolates. ISAba1-bla(OXA-82) conferred carbapenem resistance in ATCC 17978. CONCLUSIONS: Carbapenem resistance in outbreak-related isolates was mediated by conversion of OXA-66 into OXA-82 and its subsequent overexpression. This further highlights the genome plasticity of A. baumannii, leading to carbapenem resistance.
OBJECTIVES: Three clinical Acinetobacter baumannii isolates (A-C) were isolated from three separate patients during an outbreak in a hospital in Krakow, Poland. Isolate A was recovered first and was susceptible to carbapenems, whereas isolates B and C were resistant. The aim of this study was to investigate the differences in carbapenem susceptibility in these outbreak-related isolates. METHODS: Clonal relatedness was determined using rep-PCR-based DiversiLab. The bla(OXA-51-like) genes and their upstream regions were sequenced. Expression of the genes encoding OXA-51-like and the three major porins CarO, OprD-like and 33-36 kDa Omp were investigated by semi-quantitative RT-PCR. Comparison of outer membrane protein (OMP) profiles was performed using SDS-PAGE. ISAba1-bla(OXA-82) was cloned into the shuttle vector pWH1266 and transferred into A. baumannii ATCC 17978. RESULTS: The isolates were identical by rep-PCR and clustered with international clonal lineage 2. Sequencing of bla(OXA-51-like) revealed a conversion of OXA-66 (isolate A) into OXA-82 (isolates B and C). bla(OXA-82) was also associated with ISAba1. Expression analysis revealed overexpression of bla(OXA-82). There was no difference in OMP expression between the isolates. ISAba1-bla(OXA-82) conferred carbapenem resistance in ATCC 17978. CONCLUSIONS:Carbapenem resistance in outbreak-related isolates was mediated by conversion of OXA-66 into OXA-82 and its subsequent overexpression. This further highlights the genome plasticity of A. baumannii, leading to carbapenem resistance.
Authors: Cynthia M June; Taylor J Muckenthaler; Emma C Schroder; Zachary L Klamer; Zdzislaw Wawrzak; Rachel A Powers; Agnieszka Szarecka; David A Leonard Journal: Protein Sci Date: 2016-09-26 Impact factor: 6.725
Authors: Emma C Schroder; Zachary L Klamer; Aysegul Saral; Kyle A Sugg; Cynthia M June; Troy Wymore; Agnieszka Szarecka; David A Leonard Journal: Antimicrob Agents Chemother Date: 2016-09-23 Impact factor: 5.191
Authors: Scott R Evans; Andrea M Hujer; Hongyu Jiang; Carol B Hill; Kristine M Hujer; Jose R Mediavilla; Claudia Manca; Thuy Tien T Tran; T Nicholas Domitrovic; Paul G Higgins; Harald Seifert; Barry N Kreiswirth; Robin Patel; Michael R Jacobs; Liang Chen; Rangarajan Sampath; Thomas Hall; Christine Marzan; Vance G Fowler; Henry F Chambers; Robert A Bonomo Journal: J Clin Microbiol Date: 2016-12-28 Impact factor: 5.948
Authors: Mustapha M Mustapha; Bin Li; Marissa P Pacey; Roberta T Mettus; Christi L McElheny; Christopher W Marshall; Robert K Ernst; Vaughn S Cooper; Yohei Doi Journal: J Antimicrob Chemother Date: 2018-11-01 Impact factor: 5.790