In Vitro Susceptibility of 30 Strains of Chlamydia trachomatis to Rosamicin

The in vitro activity of A-56268 (TE-031), a new macrolide antibiotic, against 11 strains of Chiamydia trachomatis was determined and compared with that of four other antibiotics. A-56268 was the most active drug tested. Doxycycline, trimethoprim-sulfamethoxazole, and erythromycin had good activity but were less active in vitro than A-56268.A-56268 (TE-031) is a new macrolide antibiotic which is structurally related to erythromycin. Since erythromycin has both in vitro and in vivo activities against Chlamydia trachomatis (2, 6, 7, 9-12), we tested the activity of A-56268 against 11 strains of C. trachomatis (2 laboratory and 9 clinical strains). The susceptibilities of these strains to doxycycline, erythromycin, trimethoprim-sulfamethoxazole, and ciprofloxacin were also determined.A-56268 and erythromycin base (Abbott Laboratories, North Chicago. Ill.), trimethoprim-sulfamethoxazole (Burroughs Wellcome Co., Research Triangle Park, N.C.), ciprofloxacin (Miles Pharmaceuticals, West Haven, Conn.), and doxycycline hydrochloride (Sigma Chemical Co., St. Louis, Mo.) were prepared as stock solutions at concentrations of 1,280 ,ug/ml according to their stated potency, except for sulfamethoxazole, which was prepared at a concentration of 25,600 ,ug/ml. Stock solutions were stored at -70°C for a maximum of 2 weeks. On the day of use, the drugs were diluted to the appropriate concentration with medium containing Hanks balanced salt solution, amino acids, vitamins, 1% glutamine, 10% inactivated fetal calf serum, 5.4 g of glucose per liter, and 1 ,ug of cycloheximide per ml. Trimethoprim-sulfamethoxazole was prepared at a ratio of 1:20. The 11 strains of C. trachomatis tested included strains D (ATCC VR-885) and LGV-II (ATCC V9-902-B), and 9 clinical strains (conjunctival or genital origin). The clinical strains had been passed fewer than 10 times in the laboratory. All isolates were passed an additional two times in antibiotic-free medium before susceptibility testing and were stored at -70°C until the time of use.In vitro susceptibility studies were performed with McCoy cells which had been serially passed at least six times in antibiotic-free medium. McCoy cell monolayers were treated with trypsin and suspended with antibiotic-free medium to a concentration of about 2 x 106 cells per ml. Cell suspensions (100-,u portions) were seeded into 96-well microtiter plates and incubated at 37°C in 5% CO2 for 24 h. * Corresponding author.Duplicate plates were prepared for each drug. The monolayers were inoculated with 0.05 ml of a dilution of the C. trachomatis test strain known to yield 100 to 1,000 inclusions per well. The plates were centrifuged at 1,000 x g at 25°C for 60 min and then overlaid with 0.1 ml of each drug to yield appropriate twofold dilutions. Each dilution was tested three times. Appropriate antibiotic-free controls were included on each plate. Cultures were incubated for 48 h at 37°C in 5% C02, then fixed with absolute ethanol, and stained with 0.02 ml of fluorescein-conjugated mouse monoclonal antibody to C. tr...

Section: * Corresponding Authorsupporting

confidence: 90%

In vitro activity of A-56268 (TE-031) and four other antimicrobial agents against Chlamydia trachomatis

Segreti¹,

Kessler²,

Kapell³

et al. 1987

“…Rosaramicin and minocycline had similar activity in the day 0 experiments, but rosaramicin was more active than minocycine in the day 2 experiments. The MIC results for rosaramicin were similar to those reported previously (3,6). The results for minocycline were almost identical with those of our previous study, whereas erythromycin appeared to be slightly more active in the present study (1).…”

supporting

confidence: 92%

“…Rosaramicin, a new macrolide previously called rosamicin, has been shown to have significant activity against C. trachomatis in MIC experiments (3,6). With some antimicrobial agents, activity in MIC experiments does not necessarily correlate with activity when the antimicrobial agent is added to cells infected 48 h previously (1).…”

mentioning

confidence: 99%

In Vitro Activity of Rosaramicin Against Chlamydia trachomatis

Bowie

1980

“…Although tetracycline is recommended for the treatment of nongonococcal urethritis (20), C. trachomatis has been found to be more susceptible to rosaramicin in vitro (16 Several strains of U. urealyticum were tested for their susceptibilities to antibiotics in vitro by Spaepen and Kundsin (17) by a direct disk elution method. In this direct and rapid method, paper disks, impregnated with antibiotics, were added to growth medium (containing an acidbase pH indicator) inoculated with urine sediment.…”

mentioning

confidence: 99%

In Vitro Susceptibility of Ureaplasma urealyticum to Rosaramicin

Smith

1979

Self Cite

Thirty-two clinical isolates of Ureaplasma urealyticum were inhibited by 0.036 jig of rosaramicin per ml, whereas 25 (78%) and 13 (41%) of the strains were inhibited by this concentration of minocycline and tetracycline, respectively. These results suggest that rosaramicin may be useful for the treatment of U. urealyticum infections.The most common causes of urethritis are Neisseria gonorrhoeae and Chlamydia trachomatis; however, the etiological role of Ureaplasma urealyticum in this infection has been controversial (7,10