FIG. 1.

TET resistance patterns of several chlamydial strains. Infected cells were fixed at 50 hpi, and inclusion-forming units (IFUs) were enumerated using immunofluorescent microscopy and a monoclonal antibody against HSP60. The human C. trachomatis serovar, L2, was sensitive to a TET concentration of 0.25 μg/ml. Similar results were observed with the sensitive C. suis strain, S45. The two resistant C. suis strains, R19 and R27, formed inclusions at a TET concentration of 4 μg/ml, and no growth of R19 or R27 was observed at 5 μg of TET/ml. Values are averages of results from three wells.