Transmission Electron Microscopy of XDR Mycobacterium tuberculosis Isolates Grown on High Dose of Oﬂoxacin.
The aim of the study was to investigate behavior of resistant Mycobacterium tuberculosis (MTB) isolates under a high dose of oﬂoxacin and its morphological changes. 19 extensively drug resistant (XDR) clinical isolates of MTB were grown on Löwenstein-Jensen medium containing progressively increasing concentrations of oﬂoxacin (2, 4, 8, 16, 32 mg/L). Ultra-structure analyses of resistant isolates grown on oﬂoxacin were conducted by transmission electron microscopy (TEM). Fixation was carried out by 4% glutaraldehyde in 0.1 M sodium cacodylate buffer on 300 mesh carbon formvar copper grid. The samples were negatively stained with uranium acetate suspension. All19XDRMTBisolatesweregrownandformedcoloniessuccessfullyon2,4,8mg/L,sevenisolates on16mg/L,andfourisolateson32mg/Loﬂoxacin. Morphologicalchangesandunusualformswere detected in 8, 16 and 32 mg/L oﬂoxacin at 43%, 76.5% and 81% of cells, respectively. Swollen form (protoplast like), ghost-like cell, degraded forms, and in a few cases, detached cytoplasm from cell wall were clearly detected in high drug concentrations in comparison to control. Changes in morphology were increased with increasing oﬂoxacin concentrations (p < 0.05). Some XDR isolates could be successfully grown on high doses of oﬂoxacin (32 mg/L), but with changes in morphology. It was concluded that several magnitudes of the drug doses could not prevent growth of drug resistant forms.
Infectious Diseases Research Center (IDRC), Arak University of Medical Sciences, Arak 3848176941, Iran. arjomandzadegan@arakmu.ac.ir.
Mohammad
M
Arjomandzadegan
Department of Biology, Payame Noor University, Tehran 79134-13915, Iran. msadrnia@yahoo.com.
Maryam
M
Sadrnia
Research Institute for Epidemiology and Microbiology, Minsk 220114, Belarus. leonidtitov@tut.by.
Leonid
L
Titov
Institute for Pulmonology and Phthisiology, Minsk 220114, Belarus. larissasurkova@tut.by.
Larissa
L
Surkova
Infectious Diseases Research Center (IDRC), Arak University of Medical Sciences, Arak 3848176941, Iran. Dr.sarmadian@arakmu.ac.ir.
Hossein
H
Sarmadian
Infectious Diseases Research Center (IDRC), Arak University of Medical Sciences, Arak 3848176941, Iran. ghasemikhah@yahoo.com.
Reza
R
Ghasemikhah
Infectious Diseases Research Center (IDRC), Arak University of Medical Sciences, Arak 3848176941, Iran. rhhosseiny@yahoo.com.
Hossein
H
Hosseiny
Mycobacterium tuberculosis; XDR; oﬂoxacin; transmission electron microscope