Relative resistance to erythromycin in Chlamydia trachomatis

Abstract

Recent Chlamydia trachomatis isolates were tested in a tissue culture system for susceptibility to tetracycline, erythromycin, rosaramicin, rifampin, and clindamycin. Rifampin was the most active drug (miniimal inhibitory concentration, -0.02 ,g/ml). Tetracycline and rosaramicin were highly active, with a concentration of s0.25 ug/ml being chlamydicidal. Clindamycin was least active on a weight basis, requiring up to 16 ,ug/ml to prevent the passage of chlamydiae into a drugfree tissue culture system. Relative resistance to erythromycin was detected; two isolates were capable of limited replication in 1 ,ug/ml.

In vitro evaluation of CP-62,993, erythromycin, clindamycin, and tetracycline against Chlamydia trachomatis

“…CP-62,993 had an MBC of 1.02 ,ug/ml when assayed with serovar E; however, chlamyd- (2,3,6). The results of this study concur with those of previous studies demonstrating complete suppression of three genital strains, with the exception of the L2 lymphogranuloma venereum strain, at readily achievable drug concentrations (<1.0 ,ug/ml) (4,5). Despite this in vitro activity, occasional treatment failures have occurred, primarily due to lack of compliance by the patient (3,4,6).…”

“…The remaining wells were passed and incubated for another 48 h in culture media without antibiotics (4). The MBC was defined as the lowest concentration of antimicrobial agent preventing inclusion formation after passage (5).…”

Continuous Isolation and Characterization of Chlamydia pneumoniae from a Patient with Diffuse Panbronchiolitis

“…Tetracyclines, macrolides and some quinolones have been recommended for the treatment of chlamydial infection (19,22) since no resistant C. pneumoniae isolates have been reported whereas some clinical isolates of C. trachomatis are resistant (14,24). In the present case, however, C. pneumoniae was isolated from a patient receiving low dosages of erythromycin for 5 years.…”

Antimicrobial susceptibility and therapy of infections caused by Chlamydia pneumoniae

“…Although the relative resistance of C. trachomatis to erythromycin and doxycycline has been reported, the relationship to treatment failure is unclear (24,31). The doxycycline resistance appeared to be related to an inoculum effect, which has not yet been described for C.…”