T. M. Hooton

The prevalence of antimicrobial resistance among uropathogens causing acute uncomplicated cystitis in young women

Four hundred and fifty-two urine isolates from women with acute uncomplicated cystitis and a positive urine culture presenting to a sexually transmitted disease clinic were collected during 1989-1991, and 213 specimens were collected over 1995-1997. The predominant species was Escherichia coli, representing 68% of the isolates; others included Staphylococcus saprophyticus (8%), Group B streptococci (7%), Proteus spp. (6%), Klebsiella spp. (4%) and Enterococcus spp.(3%). More than 10% of the E. coli isolates were resistant to ampicillin, cephalothin, tetracycline and trimethoprim sulfamethoxazole (TMP SMX ) during both study periods, with the greatest increase in resistance to ampicillin and TMP/SMX between the two periods. Six hundred and four urinary tract infection isolates, including 83% E. coli, 7% S. saprophyticus, 3%, Klebsiella spp. 2% Proteus spp., 2% enterococci, 1% Enterobacter spp. and 2% other organisms, were collected from women with acute cystitis attending a university student health service during 1995. Among E. coli isolates, 25% were resistant to ampicillin, 24% to tetracycline and 11%, to TMP SMX. Resistance to fluoroquinolones was essentially absent among gram-negative pathogens. Continued evaluation of susceptibility patterns of pathogens causing acute uncomplicated cystitis to traditional as well as new antimicrobials in well defined populations is necessary to ascertain the optimal empiric therapy.

PREVALENCE OF MYCOPLASMA GENITALIUM DETERMINED BY DNA PROBE IN MEN WITH URETHRITIS

The prevalence of urethral infection with Mycoplasma genitalium was determined by use of a DNA probe in 203 men attending a sexually transmitted disease clinic. M genitalium was detected in 3 (14%) of 21 with acute gonococcal urethritis; 3 (10%) of 30 with acute chlamydia-positive non-gonococcal urethritis (NGU); 4 (13%) of 31 with acute chlamydia-negative NGU; 10 (27%) of 37 with persistent or recurrent NGU; and 10 (12%) of 84 with no urethritis. The organism was more prevalent in homosexual (11 [30%] of 37) than in heterosexual men (19 [11%] of 166; p = 0.009). These data do not support an important aetiological role for M genitalium in acute urethritis, but suggest that it may account for some cases of NGU that become persistent or recurrent. The higher prevalence of urethral infection in homosexual men suggests that M genitalium may reside in the gastrointestinal tract.

Single-dose and three-day regimens of ofloxacin versus trimethoprim-sulfamethoxazole for acute cystitis in women.

We compared the safety and efficacy of a single 400-mg dose of ofloxacin, ofloxacin (200 mg) once daily for 3 days, and trimethoprim-sulfamethoxazole (160:800 mg) twice daily for 7 days for the treatment of acute uncomplicated cystitis (urinary tract infection [UTI]) in women. At 5 weeks posttreatment, 35 (81%) of 43 patients treated with single-dose ofloxacin, 40 (89%) of 45 treated with 3 days of ofloxacin, and 41 (98%) of 42 treated with trimethoprim-sulfamethoxazole were cured (P = 0.03, single-dose ofloxacin group versus trimethoprim-sulfamethoxazole group). Retreatment for symptomatic recurrent UTI was given to 7 (16%) of 43 patients initially treated with single-dose ofloxacin, 3 (7%) of 45 patients treated with 3 days of ofloxacin, and 0 of 42 patients treated with trimethoprim-sulfamethoxazole (P = 0.01, single-dose ofloxacin group versus trimethoprim-sulfamethoxazole group). There was a trend in each of the three treatment groups toward an association between persistent or recurrent episodes of significant bacteriuria and a history of UTI in the past year and with diaphragm use. Ofloxacin was more effective than trimethoprim-sulfamethoxazole in eradicating Escherichia coli from rectal cultures during or soon after therapy, but there were no differences at later follow-up visits. Adverse effects were equally common among the three treatment groups. We conclude that single-dose ofloxacin was less effective than 7 days of trimethoprim-sulfamethoxazole for treatment of uncomplicated cystitis in women, while the 3-day ofloxacin regimen and the trimethoprim-sulfamethoxazole regimen were not significantly different in efficacy.

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.

Ofloxacin versus trimethoprim-sulfamethoxazole for treatment of acute cystitis.

We compared the safety and efficacies of ofloxacin and trimethoprim-sulfamethoxazole for the treatment of acute uncomplicated cystitis in women enrolled in a multicenter study. Data from three centers were combined for this report because the study design and study populations were identical, and patients were enrolled within an 18-month period. Cure rates for evaluable patients 4 weeks after treatment were high for all regimens: ofloxacin (200 mg) twice daily for 3 days, 22 of 25 (88%) cured; ofloxacin (200 mg) twice daily for 7 days, 42 of 49 (86%) cured; ofloxacin (300 mg) twice daily for 7 days, 25 of 25 (100%) cured; and trimethoprim-sulfamethoxazole (160/800 mg) twice daily for 7 days, 46 of 52 (88%) cured. Ofloxacin was more effective than trimethoprim-sulfamethoxazole in eradicating Escherichia coli from rectal cultures during and 1 week after treatment. Both ofloxacin and trimethoprim-sulfamethoxazole markedly reduced vaginal colonization with E. coli during and 4 weeks after therapy. Emergence of resistant coliforms in rectal flora was found in 5 (19%) of 27 patients treated with trimethoprim-sulfamethoxazole but none of 50 ofloxacin-treated patients who were studied (P = 0.004). Adverse effects were equally common among the four treatment groups. We conclude that 3 to 7 days of ofloxacin is as safe and effective as trimethoprim-sulfamethoxazole for treatment of uncomplicated cystitis in women and that ofloxacin effectively reduces the fecal and vaginal reservoirs of coliforms in such patients.

Ofloxacin versus doxycycline for treatment of cervical infection with Chlamydia trachomatis.

Women with culture-proven Chlamydia trachomatis cervical infection were randomized to receive either ofloxacin (300 mg) or doxycycline (100 mg), orally twice daily for 7 days. All 56 had negative cultures 5 to 9 days after treatment. Four weeks after treatment, 26 (93%) of 28 ofloxacin-treated patients and all 22 doxycycline-treated patients were cured. We conclude that 300 mg of ofloxacin given twice daily for 7 days provides effective therapy for chlamydial infection of the cervix.