In vitro activity of the two new 4-quinolones A56619 and A56620 against Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum and Gardnerella vaginalis

Gardnerella vaginalis: characteristics, clinical considerations, and controversies

The clinical significance, Gram stain reaction, and genus affiliation of Gardnerella vaginalis have been controversial since Gardner and Dukes described the organism as the cause of "nonspecific vaginitis," a common disease of women which is now called bacterial vaginosis. The organism was named G. vaginalis when taxonomic studies showed that it was unrelated to bacteria in various genera including Haemophilus and Corynebacterium. Electron microscopy and chemical analyses have elucidated the organism's gram-variable reaction. Controversy over the etiology of bacterial vaginosis was largely resolved by (i) studies using improved media and methods for the isolation and identification of bacteria in vaginal fluids and (ii) standardization of criteria for clinical and laboratory diagnosis. Besides G. vaginalis, Mobiluncus spp., Mycoplasma hominis, and certain obligate anaerobes are now acknowledged as participants in bacterial vaginosis. The finding that G. vaginalis, Mobiluncus spp., and M. hominis inhabit the rectum indicates a potential source of autoinfection in addition to sexual transmission. Extravaginal infections with G. vaginalis are increasingly recognized, especially when the toxic anticoagulant polyanetholesulfonate is omitted from blood cultures and when urine cultures are incubated anaerobically for 48 h. The finding that mares harbor G. vaginalis suggests that an equine model can be developed for studies of Gardnerella pathogenesis.

In vitro susceptibilities of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum to sparfloxacin and PD 127391

The in vitro activities of two investigational quinolones, sparfloxacin (previously designated AT 4140) and PD 127391, were determined for 30 strains each of Mycoplasma pneumoniae, Mycoplasma hominis, and Ureaplasma urealyticum and compared with those of ciprofloxacin, tetracycline, clindamycin, and erythromycin. Erythromycin was the most active compound against M. pneumoniae (maximum MIC, less than 0.008 microgram/ml). PD 127391 (MICs, less than 0.008 to 0.031 microgram/ml), sparfloxacin (MICs, less than 0.008 to 0.25 microgram/ml), clindamycin (MICs, less than 0.008 to 0.5 microgram/ml), and tetracycline (MICs, 0.063 to 0.25 microgram/ml) were superior to ciprofloxacin (MICs, 0.5 to 2 microgram/ml). Sparfloxacin and PD 127391 were active against M. hominis (MICs, less than 0.008 to 0.031 microgram/ml for each) at concentrations comparable to those of clindamycin (MICs, less than 0.008 to 0.063 microgram/ml) and at concentrations lower than those of ciprofloxacin (MICs, 0.125 to 0.5 microgram/ml). As expected, M. hominis was resistant to erythromycin (MICs, 32 to greater than or equal to 256 micrograms/ml). For U. urealyticum, PD 127391 (MICs, 0.031 to 0.5 microgram/ml) and sparfloxacin (MICs, 0.063 to 1 microgram/ml) were superior to erythromycin (MICs, 0.25 to 4 micrograms/ml), ciprofloxacin (MICs, 0.5 to 8 micrograms/ml), and clindamycin (MICs, 0.25 to 64 micrograms/ml. Both new quinolones were equally active against tetracycline-susceptible as well as resistant strains of M. hominis and U. urealyticum. The possible influence of medium components and/or pH on MICs was evaluated by testing a Staphylococcus aureus reference strain with each antibiotic in SP-4 broth and 10-B broth and comparing the results with published MICs for this strain. MICs determined in 10-B broth for erythromycin were affected most. This study shows that the activities of sparfloxacin and PD 127391 are similar to one another and comparable or superior to those of other drugs used to treat mycoplasmal infections. The MICs of both new quinolones were consistently 2 to several dilutions lower than those of ciprofloxacin for each species.

In vitro activity of lomefloxacin against Chlamydia trachomatis, Neisseria gonorrhoeae, Haemophilus ducreyi, Mycoplasma hominis, and Ureaplasma urealyticum

The in vitro activity of lomefloxacin, a new difluorinated quinolone antimicrobial was compared to comparative agents against organisms causing sexually transmitted diseases. Against Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, and Haemophilus ducreyi, lomefloxacin exhibited MIC90 of 2.0, 8.0, 8.0, less than or equal to 0.015, and 0.003 micrograms/ml, respectively. Overall, the lomefloxacin activity was very similar to ciprofloxacin.

Susceptibilities of genital mycoplasmas to the newer quinolones as determined by the agar dilution method

The increasing resistance of genital mycoplasmas to tetracycline poses a problem because tetracycline is one of the few antimicrobial agents active against Mycoplasma hominis, Ureaplasma urealyticum, chlamydiae, gonococci, and other agents of genitourinary-tract disease. Since the quinolones are a promising group of antimicrobial agents, the susceptibilities of M. hominis and U. urealyticum to the newer 6-fluoroquinolones were determined by the agar dilution method. Ciprofloxacin, difloxacin, and ofloxacin had good activity against M. hominis, with the MIC for 50% of isolates tested (MIC50) being 1 microgram/ml. Fleroxacin, lomefloxacin, pefloxacin, and rosoxacin had MIC50s of 2 micrograms/ml. Enoxacin, norfloxacin, and amifloxacin had MIC50s of 8 to 16 micrograms/ml, and cinoxacin and nalidixic acid were inactive (MIC50, greater than or equal to 256 micrograms/ml). Overall, the activities of 6-fluoroquinolones for ureaplasmas were similar to those for M. hominis, with MICs being the same or twofold greater. The most active 6-fluoroquinolones against ureaplasmas were difloxacin, ofloxacin, and pefloxacin, with MIC50s of 1 to 2 micrograms/ml. Ciprofloxacin was unusual in that the MIC50 for M. hominis was 1 microgram/ml, whereas the MIC50 for ureaplasmas was 8 micrograms/ml. Since the MIC50s for the most active quinolones approximate achievable concentrations in blood and urine, quinolones have promise in treating mycoplasmal infections.

In vitro activities of temafloxacin (A-62254) and four other antibiotics against Chlamydia trachomatis

The in vitro activity of temafloxacin (A-62254), a new quinolone antibiotic, against 13 strains of Chlamydia trachomatis was determined and compared with those of doxycycline, norfloxacin, ciprofloxacin, and difloxacin. Temafloxacin and difloxacin were the most active quinolones tested, with bactericidal activity comparable to that of doxycycline.

In vitro activities of T-3262, NY-198, fleroxacin (AM-833; RO 23-6240), and other new quinolone agents against clinically isolated Chlamydia trachomatis strains

The in vitro activities of three newly developed quinolone drugs (T-3262, NY-198, and fleroxacin [AM-833; RO 23-6240]) against 10 strains of clinically isolated Chlamydia trachomatis were assessed and compared with those of other quinolones and minocycline. T-3262 (MIC for 90% of isolates tested, 0.1 microgram/ml) was the most active of the quinolones. The NY-198 and fleroxacin MICs for 90% of isolates were 3.13 and 62.5 micrograms/ml, respectively.

In vitro activity of antibiotics against Ureaplasma urealyticum and Chlamydia trachomatis strains from patients with nongonococcal urethritis

The activity of minocycline, doxycycline, tetracycline, erythromycin, mepartricin and lincomycin against 35 freshly isolated Ureaplasma urealyticum strains was tested. Doxycycline was the most active. Twelve strains were resistant to minocycline and four of these were sensitive to erythromycin. Mepartricin showed no activity against the organisms at a concentration of 10 micrograms/ml. The susceptibility of 30 low-laboratory-passage Chlamydia trachomatis strains against tetracycline and erythromycin was tested. A variable degree of sensitivity to tetracycline and erythromycin was found, the median MIC values being 0.13 micrograms/ml and 0.025 micrograms/ml respectively. No resistant Chlamydia trachomatis strain was found.

Comparative in vitro activity of fleroxacin (RO 23-6240) against Ureaplasma urealyticum and Mycoplasma hominis

The susceptibility of 67 isolated Ureaplasma urealyticum, 25 Mycoplasma hominis and five Mycoplasma spp. reference strains to fleroxacin, ofloxacin, josamycin and doxycycline was determined by agar dilution. Josamycin had the best activity against Ureaplasma urealyticum, followed in order by doxycycline, ofloxacin and fleroxacin. All the strains were inhibited by josamycin at 0.4 mg/l, while only 38.8% of the strains were inhibited by doxycycline at this concentration. Mycoplasma hominis strains were more susceptible to doxycycline, ofloxacin and fleroxacin than were Ureaplasma urealyticum strains. Here, doxycycline had the best activity followed by ofloxacin, josamycin and fleroxacin. Notably, three Ureaplasma urealyticum strains and one Mycoplasma hominis strain were not inhibited by 6.4 mg/l doxycycline.

Quinolones in the treatment of gonorrhoea and Chlamydia trachomatis infections

The results of two therapeutic trials in female patients with uncomplicated urogenital gonorrhoea (A) and in male patients with uncomplicated urethral gonorrhoea (B) treated with either 200 mg and 400 mg enoxacin orally, of one therapeutic trial in male patients with uncomplicated urogenital gonorrhoea treated with either 250 mg or 500 mg ciprofloxacin orally (C) and of one therapeutic trial in male patients with non-gonococcal urethritis (NGU) treated with ciprofloxacin 1 g daily during seven days (D) are presented and compared with the results of other investigators. The cure rate in study A was 100% (n = 40) in the 400 mg group and 95.7% (n = 46) in the 200 mg group. The cure rate in study B was 92% (n = 78) in the 400 mg group and 90% (n = 77) in the 200 mg group. In both studies no antichlamydial effect of enoxacin was observed. The cure rates in study C were 100% with 250 and 500 mg. An antichlamydial effect seemed to be present. In studies A, B and C side effects were minor and rare and were mainly nausea and headache. In study D (100 patients suffering from NGU) disappearance of Chlamydia trachomatis and Ureaplasma urealyticum one day after the end of treatment was observed in 29 of 32 (91%) and 28 of 32 (88%) cases, respectively. Pyuria disappeared in 44% and 74% of the patients showed clinical cure. However, two weeks after the end of treatment Chlamydia trachomatis and Ureaplasma urealyticum were observed in respectively six and eight cases. In 30% pyuria was still absent. Side effects were only minor.(ABSTRACT TRUNCATED AT 250 WORDS)