In-vitro activity of azithromycin on Chlamydia trachomatis infected, polarized human endometrial epithelial cells.
The in-vitro activity of azithromycin on Chlamydia trachomatis infected human endometrial epithelial cells, both primary and transformed cells growing in a polarized and non-polarized orientation, was analyzed. Addition of azithromycin two hours after adsorption inoculation with continued exposure until 72 h gave an MIC90 and MBC90 of 0.063 and 0.5 mg/L, respectively. In addition, the MBC results were more pronounced in infected cells growing in a polarized orientation. Numerous small fluorescent 'spots' (presumed small abnormal inclusions) were visible in the infected cells exposed to MIC concentrations of azithromycin. Immuno-transmission electron microscopy examination revealed intracellular inclusions filled with chlamydial envelope ghosts. Since standard diagnostic antigen detection methods use anti-envelope antibodies, the aberrant envelope-filled inclusions might be interpreted as viable inclusions by fluorescent microscopy and result in high false positive readings. To simulate treatment of an infected patient, azithromycin was added at 18 h to infected cells containing many reticulate bodies and exposure continued for 54 h after which killing of chlamydiae was seen. The use of polarized human cells may offer a more relevant in-vitro model system for examining the efficacy of antimicrobial action.
Department of Microbiology and Immunology, University of North Carolina School of Medicine, Chapel Hill 27599-7290.
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PB
Wyrick
C H
CH
Davis
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ST
Knight
J
J
Choong
D017963:Azithromycin; D002478:Cells, Cultured; D002690:Chlamydia Infections / Q000382:microbiology*; D002692:Chlamydia trachomatis / Q000187:drug effects* / Q000648:ultrastructure; D004717:Endometrium / Q000187:drug effects* / Q000382:microbiology / Q000648:ultrastructure; D004848:Epithelium / Q000187:drug effects / Q000382:microbiology / Q000648:ultrastructure; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000494:pharmacology; D005260:Female; D006801:Humans; D008826:Microbial Sensitivity Tests; D008854:Microscopy, Electron; D013997:Time Factors; D014591:Uterine Diseases / Q000382:microbiology
D004917:Erythromycin; D017963:Azithromycin