The Activity of Ciprofloxacin and Other 4-Quinolones Against Chlamydia trachomatis and Mycoplasmas In Vitro

Abstract

Ciprofloxacin was found to be the most active of a group of 4-quinolone antibiotics tested against the SA2 f strain of Chlarnydia trachomatis (MBC and MIC 1.0 rag/l). Against genital isolates of Chlamydia trachomatis, ciprofloxacin was twice as active as rosoxacin.Ciprofloxacin showed similar activity to that of oxytetracycline against clinical isolates of Mycoplasma hominis and Ureaplasma urealyticum, and was 8-fold more active than rosoxacin against the latter.Recently, a number of new 4-quinolones have become available. In comparison with chemically similar, older agents such as nalidixic acid, the new agents have a wider spectrum and greater activity.Their activity against Neisseria gonorrhoeae is particularly marked (1), including high activity against beta-lactamase producing strains. In view of their potential use in the treatment of gonorrhoea, we examined the activity of four second generation 4-quinolone derivatives, nalidixic acid and oxolinic acid against the SA2 f strain of Chlamydia trachomatis in cell culture. The 4-quinolones examined were norfloxacin (Thomas Morson), rosoxacin and WIN49375 (Sterling Winthrop) and ciprofloxacin (Bayer). The activity of ciprofloxacin and rosoxacin against ten recent clinical isolates of Chlamydia trachomatis and Ureaplasrna urealyticum and the activity of ciprofloxacin against ten recent clinical isolates ofMycoplasma hominis were also investigated. Materials and MethodsChlamydia trachomatis. The minimum inhibitory concentration (MIC) of nalidixic acid, oxolinic acid, rosoxacin, norfloxacin, WIN 49375, and ciprofloxacin were first determined against a standard strain of Chlamydia trachomatis. This strain, designated SA2f, is an LGVII serotype which serologically cross-reacts widely with the genital serotypes D-K. The activity of eiprofloxacin was further investigated by determining the minimum bactericidal concentration (MBC) against the SA2f strain. The MICs of rosoxacin and ciprofloxacin against ten recently isolated strains of Chlamydia traehomatis were then investigated. All ten strains were isolated from specimens obtained from the genital tract of patients attending a clinic for sexually transmitted diseases.1Department of Clinical Microbiology and 2Genito-Urinary Medicine University College Hospital, London WC1, England. Determination of MIC.The method used has been described elsewhere (2). Doubling dilutions of the antimicrobial agents were prepared in antimicrobial-free Chlamydia growth medium. One ml of each dilution was added to a flatbottomed plastic tube containing a cover slip monolayer of 5-iodo-2-deoxyuridine (IUDR) treated MCCoy ceils. A suspension of chlamydiae containing approximately 200 inclusion-forming units per ml was added to each tube. After centrifugation at 3,000 Xg for 1 h, the tubes were incubated for 38-40 h at 35 ~ The cover slips were removed, and the cell monolayer fixed with methanol and stained with either Giemsa for examination of autofluorescence using darkfield illumination, or iodine for examination of stained inclusions by b...

In vitro activity of A-56619 (difloxacin), A-56620, and other new quinolone antimicrobial agents against genital pathogens

“…A-56619 was the most active quinolone against both the lymphogranuloma venereum and occulogenital strains of C. trachomatis tested, having MICs eightfold lower than those of ciprofloxacin. The isolates were fully resistant to norfloxacin, as previously reported (1,9,10,14,17). The agents showed poor activity against G. vaginalis and U. urealyticum.…”

“…We found most U. urealyticum strains tested to be resistant to the quinolones. Although lower MICs of ciprofloxacin against U. urealyticum have been reported (14), similar MIC ranges have also been documented (1,8,17).…”

“…All the quinolones were highly active against Neisseria gonorrhoeae. A-56619 had the lowest MICs against Chlamydia trachomatis (MIC range, 0.125 to 0.25 ,ug/ml) and Haemophilus ducreyi (MIC for 90% of isolates tested, 0.1 ,ug/ml).The newer quinolone antimicrobial agents have been shown to have excellent activity in vitro against gonococci, including ,B-lactamase-producing strains (3,11,13,16,18), and moderate activity in vitro against Chlamydia trachomatis (2,10,14).We compared the activities of A-56619 (difloxacin), A-56620, ciprofloxacin, norfloxacin, ofloxacin, and antimicrobial agents now used for the treatment of genital infections against clinical isolates of Neisseria gonorrhoeae, Haemophilus ducreyi, Gardnerella vaginalis, Ureaplasma urealyticum, and C. trachomatis.Antimicrobial reference standards and sources were as follows: A-56619, A-56620, and erythromycin, Abbott Lab of M. hominis and 2-day-old broth cultures of U. urealyticum were inoculated into 100 ,ul of twice the required final concentration of each of the antibiotic dilutions in U-well microtiter plates. Controls containing medium only, medium plus antimicrobial agent, and medium plus M. hominis or U. urealyticum were included.…”

“…The newer quinolone antimicrobial agents have been shown to have excellent activity in vitro against gonococci, including ,B-lactamase-producing strains (3,11,13,16,18), and moderate activity in vitro against Chlamydia trachomatis (2,10,14).…”

Quinolones: a class of antimicrobial agents

“…Comparison of ciprofloxacin, norfloxacin, pefloxacin, pipemidic acid and a variety of nonquinolone antibacterial agents (nitrofurantoin, sulfamethoxazole, trimethoprim, cephradine and amoxicillin) demonstrated that ciprofloxacin had the broadest spectrum of activity against all gram-negative bacteria and streptococci tested, with the exception of Enterococcus faecalis and Streptococcus pneumoniae (Hoogkamp-Korstanje, 1984). Compared with rosoxacin, norfloxacin, nalidixic acid and oxolinic acid the activity of ciprofloxacin against Chlamydia trachomatis, Mycoplasma hominis and Ureaplasma urealyticum was found to be at least twice as high (Ridgway et al, 1984). Enrofloxacin has structural similarity to ciprofloxacin and has a similar antibacterial spectrum to ciprofloxacin against Haemophilus sp., Pasteurella sp.…”