Ultrastructural changes caused by polymyxin B and meropenem in multiresistant Klebsiella pneumoniae carrying blaKPC-2 gene.

Ultrastructural changes caused by polymyxin B and meropenem in multiresistant Klebsiella pneumoniae carrying blaKPC-2 gene. J Med Microbiol. 2016 Oct 17;: Authors: Scavuzzi A, Alves LC, Veras DL, Brayner FA, Lopes AC Abstract The ultrastructural alterations caused by polymyxin B, meropenem and by the association between polymyxin B and meropenem were investigated in 2 multiresistant isolates of K. pneumoniae (K3-A2 and K12-A2) carriers of blaKPC-2, coming from infection and colonization in patients of a public hospital in Recife, Brazil. The ultrastructural changes were detected by transmission electron microscopy and scanning. The susceptibility of the isolates to antimicrobials was tested by the disk diffusion method and microdilution in broth. The analysis by electron microscopy showed that the isolates presented morphological and ultrastructural cellular changes when subjected to a clinically relevant concentration of antimicrobials alone or associated ones. When subjected to meropenem, they presented retraction of the cytoplasmic material, rupture of the cell wall and extravasation of the cytoplasmic content. When submitted to polymyxin B, the isolates showed condensation of the ribosomes, DNA clotting, cell wall thickening and the presence of membrane compartment. When subjected to the association of polymyxin B and meropenem, the isolates showed a higher intensity of the ultrastructural changes visualized. This is the first re...
Source: Journal of Medical Microbiology - Category: Microbiology Authors: Tags: J Med Microbiol Source Type: research