title: Evaluation of Organelle Changes in Promastigotes of Unresponsive Leishmania Tropica to Meglumine Antimoniate in Comparison with Sensitive and Standard Isolates by Electron Microscopy.
abstract: BACKGROUND
  The control of leishmaniasis faces serious challenges because of resistance to the first-line antimonial drugs. We aimed to evaluate the differences in organelle changes of cultivated promastigotes obtained from skin lesions of sensitive and unresponsive isolates to meglumine antimoniate (Glucantime) by electron microscopy.
  
  
  METHODS
  This study was done in Bam city, southeastern Iran, in which the incidence of disease has sharply increased since the earthquake in 2003. The samples were taken from 66 patients who were referred to the cutaneous leishmaniasis (CL) treatment center in Bam. A questionnaire was completed for each individual, recording their demographic characteristics and CL status. The scraping smears provided from the edge of active lesions with sterile blades were fixed with methanol, stained by Giemsa, and examined under a compound light microscope for amastigote form simultaneously. To prepare the specimens for transmission electron imaging, promastigotes were centrifuged and resuspened.
  
  
  RESULTS
  Transmission electron microscopic study of the cultivated promastigotes revealed that there were alterations in the organelles and structures of sensitive isolates compared with unresponsive and standard ones. Organelles and structures such as mitochondria, kinetoplast, microtubules, cytoplasmic vacuoles, plasma membrane and vesicles were studied. The alterations such as disintegration of kinetoplast into thin filaments and condensation of kinetoplast DNA core, changes in size, number and location of vesicles and microtubules were observed. We noted intense cytoplasmic vacuolization, and considerable swelling of mitochondria.
  
  
  CONCLUSIONS
  The significance and relevance of these changes might help understand drug resistance patterns and help localize the best target site for inactivating the organism.
authors.affiliation: Leishmaniasis Research Center, Kerman, Iran.
authors.forename: Mitra
authors.initials: M
authors.lastname: Bahreini
authors.affiliation: Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Bolorizadeh
authors.affiliation: Department of Pathology, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
authors.forename: Shahriar
authors.initials: S
authors.lastname: Dabiri
authors.affiliation: Leishmaniasis Research Center, Kerman, Iran.
authors.forename: Iraj
authors.initials: I
authors.lastname: Sharifi
keywords: Cutaneous leishmaniasis; drug resistance; electron microscopy; meglumine antimoniate; organelles alteration