19786595

pubmed:Citation

12

The prevalence of infections caused by multidrug-resistant gram-negative Acinetobacter baumannii strains and the lack of novel antibiotics under development are posing a global dilemma, forcing a resurgence of the last-line antibiotic colistin. Our aim was to use atomic force microscopy (AFM) to investigate the morphology and topography of paired colistin-susceptible and -resistant cells from colistin-heteroresistant A. baumannii strains as a function of bacterial growth phase and colistin exposure. An optimal AFM bacterial sample preparation protocol was established and applied to examine three paired strains. Images revealed rod-shaped colistin-susceptible cells (1.65 +/- 0.27 microm by 0.98 +/- 0.07 microm) at mid-logarithmic phase, in contrast to spherical colistin-resistant cells (1.03 +/- 0.09 microm); the latter were also more diverse in appearance and exhibited a rougher surface topography (7.05 +/- 1.3 nm versus 11.4 +/- 2.5 nm for susceptible versus resistant, respectively). Cellular elongation up to approximately 18 microm at stationary phase was more commonly observed in susceptible strains, although these "worm-like" cells were also observed occasionally in the resistant population. The effects of colistin exposure on the cell surface of colistin-susceptible and -resistant cells were found to be similar; topographical changes were minor in response to 0.5 microg/ml colistin; however, at 4 microg/ml colistin, a significant degree of surface disruption was detected. At 32 microg/ml colistin, cellular clumping and surface smoothening were evident. Our study has demonstrated for the first time substantial morphological and topographical differences between colistin-susceptible and -resistant cells from heteroresistant A. baumannii strains. These results contribute to an understanding of colistin action and resistance in regard to this problematic pathogen.

http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-10023344, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-10388679, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-10492501, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-10831437, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-1176588, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-12356788, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-14654232, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-15152201, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-15933006, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-16189084, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-16701623, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-1685507, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-16931410, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-16940086, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17037942, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17234038, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17275779, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17289768, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17305384, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17620384, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17682994, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17702663, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17878146, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-17954699, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-18556125, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-1856133, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-18625681, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-18957593, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-19035777, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-19058855, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-19441416, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-2292523, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-7860599, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-8964033, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-9033483, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-9163451, http://linkedlifedata.com/resource/pubmed/commentcorrection/19786595-9449254

http://linkedlifedata.com/resource/pubmed/journal/0315061

http://linkedlifedata.com/resource/pubmed/chemical/Anti-Bacterial Agents, http://linkedlifedata.com/resource/pubmed/chemical/Colistin

Dec

pubmed-author:HartleyPatrick GPG, pubmed-author:LarsonIanI, pubmed-author:LiJianJ, pubmed-author:NationRoger LRL, pubmed-author:SoonRachel LRL

53

Y

2011-8-1

2009

Facility for Anti-Infective Drug Development and Innovation, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.