Single dose ciprofloxacin for treating gonococcal infections in men

Emergence of in vitro resistance to fluoroquinolones in Neisseria gonorrhoeae isolated in Japan

To investigate emerging fluoroquinolone resistance in Neisseria gonorrhoeae isolated in Japan, we compared the in vitro antimicrobial susceptibilities of 79 gonococcal isolates from 1992 through 1993 to 14 fluoroquinolones and 14 other antibiotics with those of 27 isolates from between 1981 and 1984. The MICs at which 90% of the isolates were inhibited by nine fluroquinolones, including norfloxacin, enoxacin, ofloxacin, ciprofloxacin, tosufloxacin, lomefloxacin, fleroxacin, levofloxacin, and sparfloxacin, for isolates from 1992 to 1993 were 8- or 16-fold higher than those for isolates from 1981 to 1984. Furthermore, the MICs at which 90% of the isolates were inhibited by five fluroquinolones, including OPC-17116, T-3761, DU-6859a, AM-1155, and Q-35, that have recently been synthesized but have not yet been introduced for clinical use in Japan for isolates from 1992 to 1993 were also 2- to 16-fold higher than those for isolates from 1981 to 1984. The gonococcal isolates from 1992 to 1993 showed no significant decreases in susceptibility to beta-lactams, tetracyclines, macrolides, and spectinomycin, compared with those for isolates from 1981 to 1984. Our data indicate that the incidence of gonococcal strains with decreased susceptibilities to fluoroquinolones is increasing in Japan.

Reduced uptake and accumulation of norfloxacin in resistant strains of Neisseria gonorrhoeae isolated in Japan

OBJECTIVE

To investigate the alteration of cell permeability toward fluoroquinolones in Neisseria gonorrhoeae, which is a major quinolone-resistance mechanism along with the alteration of DNA gyrase in gram-negative bacteria. The prevalence of fluoroquinolone-resistant N gonorrhoeae strains is rapidly increasing in Japan.

MATERIALS AND METHODS

The uptake and accumulation of norfloxacin by gonococcal cells, including six clinical and five World Health Organization (WHO) reference strains, were measured. Of the six clinical strains, two were highly resistant to norfloxacin (MIC 8.0 and 4.0 micrograms/ml), two were moderately resistant (MIC 1.0 and 0.5 microgram/ml), and two were sensitive (MIC 0.063 and 0.004 microgram/ml). All five WHO reference strains were sensitive to norfloxacin (MIC < or = 0.001 to 0.063 microgram/ml).

RESULTS

Mean initial norfloxacin uptake in the four resistant strains (104 ng/mg of dry cells) was significantly lower than that in the seven sensitive strains (158 ng/mg of dry cells) (p < 0.05). The mean uptake after 20 minutes was also significantly lower in the four resistant strains (130 ng/mg of dry cells) than in the seven sensitive strains (194 ng/mg of dry cells) (p < 0.05). However, there was no significant difference in mean norfloxacin accumulation after 20 minutes between the four resistant strains (26 ng/mg of dry cells) and the seven sensitive strains (36 ng/mg of dry cells). The accumulation of norfloxacin after 20 minutes was almost zero in two of the four resistant strains, while the remaining two strains accumulated norfloxacin as well as the sensitive strains.

CONCLUSIONS

These findings suggest that alteration of bacterial cell permeability is a quinolone-resistance mechanism in N gonorrhoeae isolated in Japan, and that this bacteria may exhibit other mechanisms such as alteration of DNA gyrase.

High prevalence of Neisseria gonorrhoeae strains with reduced susceptibility to fluoroquinolones in Japan

OBJECTIVE

To study the antibiotic susceptibility of Neisseria gonorrhoeae strains isolated in Japan and, in particular, to examine the possibility of emerging fluoroquinolone resistance.

MATERIALS AND METHODS

Sixty-nine strains of Neisseria gonorrhoeae isolated in 1992 were tested for susceptibility to 15 antibiotics including fluoroquinolones and were seroclassified. Twenty-seven strains isolated from 1981 to 1984 were also evaluated as controls.

RESULTS

The MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the isolates from 1992 were 2.0, 1.0, and 0.5 microgram/ml, respectively. The MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the isolates from 1981-84 (controls) were 0.25, 0.125, and 0.063 microgram/ml, respectively. These results indicate that the MIC90 values of norfloxacin, ofloxacin, and ciprofloxacin against the strains from 1992 were 8-fold higher than those against the strains from 1981-84. However, there were no significant differences in susceptibility to beta-lactams, tetracyclines, macrolides, and spectinomycin between the isolates from 1992 and those from 1981-84. The majority of the isolates belonged to the WII/WIII serogroup. There was no relationship between fluoroquinolone resistance and serogroup.

CONCLUSIONS

Fluoroquinolones have been used frequently as first-line therapy and have provided excellent clinical efficacy for gonococcal infections for the last several years in Japan. However, our data indicate that a rapid decrease in the susceptibility of Neisseria gonorrhoeae to fluoroquinolones is occurring in our country.

Comparison of ciprofloxacin and ceftriaxone as single-dose therapy for uncomplicated gonorrhea in women

Although women bear the brunt of gonococcal infection-related morbidity, few large studies of gonorrhea treatment in women have been conducted. In a multicenter, double-blind, placebo-controlled trial, 181 evaluable women with uncomplicated gonorrhea were treated with ciprofloxacin (250 mg orally; 94 women) or ceftriaxone (250 mg intramuscularly; 87 women). Twenty-four percent of the participants were infected with antibiotic-resistant Neisseria gonorrhoeae. Cervical gonorrhea was cured in 100% (93 of 93) of the women treated with ciprofloxacin and 99% (83 of 84) receiving ceftriaxone. All pharyngeal (n = 5) or rectal (n = 20) infections treated with ciprofloxacin were cured, as were ceftriaxone-treated patients with pharyngeal (n = 6) or rectal (n = 21) infection. Geometric mean MICs (range) for 248 pretreatment isolates were: penicillin, 0.28 (0.015 to 8.0); tetracycline, 0.46 (0.06 to 4); ciprofloxacin, 0.003 (0.002 to 0.015); and ceftriaxone, 0.004 (0.001 to 0.125) microgram/ml. Both drugs were well tolerated. Despite the high prevalence of antibiotic-resistant gonococci in these populations, 250 mg of oral ciprofloxacin was as effective as an injection of ceftriaxone.

Pefloxacin and ciprofloxacin in the treatment of uncomplicated gonococcal urethritis in males [corrected]

OBJECTIVE

To study the effectiveness of single-dose pefloxacin and ciprofloxacin in the treatment of uncomplicated gonococcal urethritis in males.

SETTING

Department of STD Control, Kelantan Road, Singapore.

METHOD

160 male patients with uncomplicated gonococcal urethritis were assigned alternately to receive single oral doses of either pefloxacin 800 mg or ciprofloxacin 250 mg.

RESULTS

Of the pefloxacin group 98.5% (65/66 patients) and of the ciprofloxacin group 98.6% (74/75 patients) were cured of gonorrhoea. The rates of post-gonococcal urethritis were 64.3% and 67.3% in the pefloxacin and ciprofloxacin groups, respectively. Both drugs were well tolerated and reported side-effects were minor and transient. There was a high incidence of penicillinase-producing gonococci (32.3%) and tetracycline resistant isolates with MIC > or = 2 mg/l (99.3%). High level tetracycline resistance (MIC > or = 16 mg/l) was found in 7.4% of isolates.

CONCLUSION

The drugs in the dosages studied may be recommended for first-line treatment of uncomplicated gonococcal urethritis in males in Singapore. However, the emergence of bacterial resistance to the fluoroquinolones in the literature calls for vigilance in the monitoring of antimicrobial susceptibility [corrected].

Interpretive criteria for susceptibility testing of CI-960 (PD127391, AM-1091), fleroxacin, lomefloxacin, and temafloxacin against Neisseria gonorrhoeae, including drug stability in GC agar medium

CI-960, fleroxacin, lomefloxacin, and temafloxacin were tested against over 100 strains of Neisseria gonorrhoeae. Each organism was tested in triplicate by using agar dilution and disk diffusion methods recommended by the National Committee for Clinical Laboratory Standards. CI-960 was the most potent compound, with a MIC against 90% of the strains tested of 0.008 microgram/ml, and the least active was fleroxacin (MIC against 90% of strains, 0.12 microgram/ml). Only the susceptible interpretive category was recommended for the CI-960 tests as follows: 5-micrograms disk, greater than or equal to 39 mm (MIC correlate, less than or equal to 0.12 microgram/ml). Three interpretive categories were proposed for the other fluoroquinolones as follows: fleroxacin, 5-micrograms disk susceptible at greater than or equal to 33 mm (MIC correlate, less than or equal to 0.25 microgram/ml), intermediate at 28 to 32 mm (MIC correlate, 0.5 microgram/ml), and resistant at less than or equal to 27 mm (MIC correlate, greater than 0.5 microgram/ml); lomefloxacin, 10-micrograms disk susceptible at greater than or equal to 35 mm (MIC correlate, less than or equal to 0.12 microgram/ml), intermediate at 28 to 34 mm (MIC correlates, 0.25 to 0.5 microgram/ml), and resistant at less than or equal to 27 mm (MIC correlate, greater than 0.5 microgram/ml); and temafloxacin, 5-micrograms disk susceptible at greater than or equal to 36 mm (MIC correlate, less than or equal to 0.06 microgram/ml), intermediate at 28 to 35 mm (MIC correlates 0.12 to 0.25 microgram/ml), and resistant at less than or equal to 27 mm (greater than 0.25 microgram/ml). Interpretive agreement between disk diffusion results and the MICs was 100% for each agent, with the exception of lomefloxacin, which had a 0.9% minor error. All drugs were stable in GC agar medium for at least 21 days when stored at 2 to 5 degrees C.

Single-dose trospectomycin for chlamydial urethritis in men

Trospectomycin is an aminocyclitol analog of spectinomycin with significant in vitro activity against Chlamydia trachomatis. A single 1-g intramuscular dose was administered to 10 men with symptomatic, culture-positive chlamydial urethritis. Trospectomycin was well tolerated but failed to eradicate chlamydial infection, as determined by cultures obtained approximately 1 week after treatment.

Fluoroquinolone antibiotics. Microbiology, pharmacokinetics and clinical use

The newer fluoroquinolones are a major advance in antimicrobial chemotherapy. They inhibit the supercoiling activity of the DNA gyrase enzyme, thus exerting their antibacterial action on DNA and RNA synthesis, resulting in a biphasic response and killing of susceptible organisms. The newer fluoroquinolones have an extended antimicrobial spectrum compared to their older congeners, and are highly active against most Gram-negative pathogens including the Enterobacteriaceae and Pseudomonas aeruginosa. While Staphylococcus aureus and coagulase-negative staphylococci are usually susceptible to the fluoroquinolones, streptococci are generally more resistant and enterococci are resistant. All of the newer fluoroquinolones may be administered orally and most of them have been administered parenterally. They are widely distributed in the body, attaining therapeutic concentrations in most tissues. All of the fluoroquinolones have long half-lives and may be administered once or twice daily. The fluoroquinolones have proved effective in many infections, including uncomplicated or complicated urinary tract infections, respiratory tract infections, gonorrhoea, bacterial gastroenteritis, and soft tissue infections due to Gram-negative organisms. In general, success has been notable in the management of Gram-negative infections but less so with Gram-positive infections. Resistance has occurred and is proving a problem with P. aeruginosa in some cystic fibrosis patients, but as yet no plasmid-mediated resistance has developed. Cross-resistance occurs between the quinolones but only rarely with other classes of antibacterial drugs. The fluoroquinolones have an excellent safety record and their adverse effects, which include hypersensitivity reactions, dizziness, headache, gastrointestinal disturbance and minor haematological abnormalities are usually mild and transient. However, the fluoroquinolones have been found to damage juvenile weight-bearing joints in animals and are therefore only to be used with caution in children; transient arthralgia has been reported in a cystic fibrotic teenager on long term ciprofloxacin therapy. All of the fluoroquinolones except ofloxacin are associated with a variable increase in the serum concentration of theophylline, warfarin and caffeine. Thus, the fluoroquinolones are an attractive option in the management of many infections. Cost and possible resistance, however, should counsel caution in their use, and may limit them to situations where a cheaper antimicrobial of equivalent efficacy is not available.

Evaluation of 500- and 1,000-mg doses of ciprofloxacin for the treatment of chancroid

A randomized, double-blind study was performed comparing ciprofloxacin in a 500-mg single dose with 1,000 mg (500-mg doses given 12 h apart) for the treatment of chancroid in Thailand. Haemophilus ducreyi was isolated from 87 (48%) of 180 men with a clinical diagnosis of chancroid. For men with ulcers that were culture positive for H. ducreyi, rates of cure were 100% in the 500-mg group and 98% in the 1,000-mg group. For men with ulcers that were culture negative for H. ducreyi, rates of cure were 93% in the 500-mg group and 96% in the 1,000-mg group. The MIC of ciprofloxacin for 50% of isolates among 85 isolates of H. ducreyi was 0.007 micrograms/ml (range, 0.002 to 0.03 micrograms/ml). No significant adverse effects were detected in either group. These data indicate that both of these treatment regimens are equally effective therapies for chancroid in Thailand.

Ciprofloxacin. A review of its antibacterial activity, pharmacokinetic properties and therapeutic use

Ciprofloxacin is one of a new generation of fluorinated quinolones structurally related to nalidixic acid. The primary mechanism of action of ciprofloxacin is inhibition of bacterial DNA gyrase. It is a broad spectrum antibacterial drug to which most Gram-negative bacteria are highly susceptible in vitro and many Gram-positive bacteria are susceptible or moderately susceptible. Unlike most broad spectrum antibacterial drugs, ciprofloxacin is effective after oral or intravenous administration. Ciprofloxacin has been most extensively studied following oral administration. It attains concentrations in most tissues and body fluids which are at least equivalent to the minimum inhibitory concentration designated as the breakpoint for bacterial susceptibility in vitro. The results of clinical trials with orally and intravenously administered ciprofloxacin have confirmed the potential for its use in a wide range of infections, which was suggested by its in vitro antibacterial and pharmacokinetic profiles. It has proven an effective treatment for many types of systemic infections as well as for both acute and chronic infections of the urinary tract. Ciprofloxacin generally appeared to be at least as effective as alternative orally administered antibacterial drugs in the indications in which they were compared, and in some indications, to parenterally administered antibacterial therapy. However, further studies are needed to fully clarify the comparative efficacy of ciprofloxacin and standard antibacterial therapies. Bacterial resistance to ciprofloxacin develops infrequently, both in vitro and clinically, except in the setting of pseudomonal respiratory tract infections in cystic fibrosis patients. The drug is also well tolerated. Thus, as an orally active, broad spectrum and potent antibacterial drug, ciprofloxacin offers a valuable alternative to broad spectrum parenterally administered antibacterial drugs for use in a wide range of clinical infections, including difficult infections due to multiresistant pathogens.

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)

In vitro activity and mode of action of fluoroquinolones

The in vitro activity of nine fluoroquinolones has been determined by agar dilution method against 1100 clinical isolates of different microorganisms: 412 Enterobacteriaceae, 93 non-fermenters, 398 enteropathogens, 140 Gram-positive cocci, 31 Haemophilus and 26 gonococci. The bactericidal activity tested in broth against different representative isolates was generally similar to the inhibitory concentration. Killing kinetics studied in different isolates of Enterobacteriaceae, in Pseudomonas aeruginosa, Vibrio cholerae, Staphylococcus aureus and Streptococcus faecalis showed a very rapid bactericidal effect, after 2 to 8 h of contact, in all species except in Streptococcus faecalis.

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

The in vitro activities of two new carboxyquinolones, A-56619 (difloxacin) and A-56620, were compared with those of ciprofloxacin, norfloxacin, and ofloxacin against genital tract pathogens. 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 micrograms/ml) and Haemophilus ducreyi (MIC for 90% of isolates tested, 0.1 micrograms/ml).

Quinolones in the treatment of gonorrhoea and Chlamydia trachomatis infections

123 Female patients suffering from uncomplicated urogenital gonorrhoea were treated with either 200 mg or 400 mg enoxacin. The cure rate in the 400 mg group was 100%; the cure rate in the 200 mg group was 95.7% 212 Male patients suffering from urethral gonorrhoea were treated with either 250 mg or 500 mg ciprofloxacin (one tablet). Cure rates in both groups were 100%. Post-gonococcal urethritis was observed in 31 out of 85 (36%) patients in the first, and 21 out of 79 (27%) in the second group. In a pilot study 42 male patients suffering from non-gonococcal urethritis were treated during one week with I g ciprofloxacin daily. In 22 patients Chlamydia trachomatis was isolated from the urethra: in 20 of these 22 cases Chlamydia trachomatis could not be cultured after treatment (cure rate 91%), but in 4 of these 20 cases (20%) and in 8 of the 20 Chlamydia trachomatis negative cases (40%) urine-sediment abnormalities were present after treatment.