Antibiotherapy and pathogenesis of uncomplicated UTI: difficult relationships

In a time when conventional antibiotics are becoming increasingly less effective for treatment of infections, the relationship between bacteria and antimicrobial resistance is becoming more and more complicated. This paper provides a current review of studies reported in the literature pertaining to the antibiotherapy of human urinary tract infections (UTI), in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to (bio)pathogenesis of uncomplicated cystitis. Features associated with the antibiotherapy of UTI such as development of resistance are presented in the text systematically. This review discusses recent advances in the understanding of how the predominant uropathogen Escherichia coli interacts with its host and leads to infection; so one can understand some of the reasons behind antibiotherapy failures.

Fluconazole susceptibility of vaginal isolates obtained from women with complicated Candida vaginitis: clinical implications

Despite considerable evidence of azole resistance in oral candidiasis due to Candida species, little is known about the azole susceptibilities of the genital tract isolates responsible for vaginitis. The fluconazole susceptibilities of vaginal isolates obtained during a multicenter study of 556 women with complicated Candida vaginitis were determined by evaluating two fluconazole treatment regimens. Of 393 baseline isolates of Candida albicans, 377 (96%) were highly susceptible to fluconazole (MICs, <8 microg/ml) and 14 (3.6%) were resistant (MICs, >or=64 microg/ml). Following fluconazole therapy, one case of in vitro resistance developed during 6 weeks of monitoring. In accordance with the NCCLS definition, in vitro fluconazole resistance correlated poorly with the clinical response, although a trend of a higher mycological failure rate was found (41 versus 19.6% on day 14). By using an alternative breakpoint of 1 micro g/ml, based upon the concentrations of fluconazole achievable in vaginal tissue, no significant differences in the clinical and mycological responses were observed when isolates (n = 250) for which MICs were <or=1 microg/ml were compared with isolates (n = 30) for which MICs were >1 microg/ml, although a trend toward an improved clinical outcome was noted on day 14 (odds ratio, >2.7; 95% confidence interval, 0.91, 8.30). Although clinical failure was uncommon, symptomatic recurrence or mycological relapse almost invariably occurred with highly sensitive strains (MICs, <1.0 microg/ml). In vitro fluconazole resistance developed in 2 of 18 initially susceptible C. glabrata isolates following fluconazole exposure. Susceptibility testing for women with complicated Candida vaginitis appears to be unjustified.

Treatment of complicated Candida vaginitis: comparison of single and sequential doses of fluconazole

OBJECTIVE

An attempt was made to validate recent recommendations that women with complicated Candida vaginitis (severe or recurrent, non-albicans Candida spp or abnormal host) require longer-duration antifungal therapy to achieve clinical cure and mycologic eradication.

STUDY DESIGN

A prospective, multicenter, randomized, double-blind study was performed comparing a single dose of 150 mg of fluconazole with 2 sequential 150-mg doses of fluconazole given 3 days apart.

RESULTS

Five hundred fifty-six women with severe or recurrent Candida vaginitis were enrolled, and 398 had at least one postbaseline evaluation (intent to treat) and of these 309 were fully evaluable (efficacy-valid). At baseline, 92% of vaginal isolates were Candida albicans. The 2-dose fluconazole regimen achieved significantly higher clinical cure rates in women with severe vaginitis when evaluated on day 14 (P =.015) and higher clinical and mycologic responses persisted at day 35. Women with recurrent but not severe vaginitis did not benefit clinically short term by the additional fluconazole dose. Multivariate logistic regression analysis showed that being infected with non-albicans Candida predicted significantly reduced clinical and mycologic response regardless of duration of therapy. Fluconazole therapy was well tolerated and free of serious adverse effects.

CONCLUSION

Treatment of Candida vaginitis requires individualization, and women with severe Candida vaginitis achieve superior clinical and mycologic eradication with a 2-dose fluconazole regimen.

Randomized phase I trial of two different combination foscarnet and ganciclovir chronic maintenance therapy regimens for AIDS patients with cytomegalovirus retinitis: AIDS clinical Trials Group Protocol 151

AIDS patients with newly diagnosed cytomegalovirus (CMV) retinitis who had just completed a 14-day course of ganciclovir induction therapy were randomly assigned to an alternating or concurrent combination regimen of chronic ganciclovir-foscarnet therapy for CMV retinitis. Each regimen used lower weekly cumulative doses of each drug than standard monotherapy maintenance treatment regimens. Dose-limiting toxicity attributable to foscarnet occurred in only 2 (7%) of 29 evaluatable patients, and no patients experienced dose-limiting nephrotoxicity. Although absolute neutrophil counts < 500 cells/microL occurred in 11 (38%) of 29 patients, all who subsequently used adjunctive granulocyte colony-stimulating factor had severe neutropenia prevented. Severe toxicity of any type and neutropenia, in particular, occurred significantly more frequently in patients assigned to the concurrent treatment regimen. CMV was isolated from none of 21 patients who had urine cultured and from only 1 of 24 who had blood cultured while being treated during the study (median evaluation, 12 weeks). This suggests that combination therapy provides better in vivo antiviral activity in suppressing CMV replication than previously reported with monotherapy regimens.

Urinary excretion of Tamm-Horsfall protein in women with recurrent urinary tract infections

Since MS-fimbriated bacteria adhere to Tamm-Horsfall protein, it has been suggested that Tamm-Horsfall protein may trap urinary pathogens and prevent them from colonizing the mucosal surfaces of the urinary tract. To test the hypothesis that low urinary Tamm-Horsfall protein excretion rates predispose to urinary tract infection we obtained serial urine samples from 17 women with and 18 without a history of recurrent urinary tract infection. None of the women had known structural abnormalities of the urinary tract. Concentrations of Tamm-Horsfall protein in urine were measured with a sensitive enzyme-linked immunosorbent assay method. On the average, 3 urine samples per person collected within 3 to 6 months were analyzed. The mean Tamm-Horsfall protein excretion of women with recurrent urinary tract infection was 57.0 mg./l. and that of controls was 66.3 mg./l.; this difference was not statistically significant. The mean coefficient of variation was 44.2 and 62.1%, respectively. We conclude that urinary Tamm-Horsfall protein concentration is not significantly decreased in women with recurrent urinary tract infection compared with controls, and that excretion varies widely in repeat samples obtained from the same individual.