Single dose azithromycin for the treatment of chancroid: a randomized comparison with erythromycin

BACKGROUND AND OBJECTIVES

Chancroid is endemic in sub-Saharan Africa and enhances the sexual transmission of the human immunodeficiency virus Type 1 (HIV-1). Azithromycin is an orally absorbed macrolide antibiotic that is active against Haemophilus ducreyi, the causative agent of chancroid, and has pharmacokinetic properties that are suitable for single dosing.

STUDY DESIGN

In a randomized single-blinded study of 127 men presenting to a referral STD clinic with culture proven chancroid, we compared the efficacy of azithromycin, administered as a single 1 g dose, with erythromycin 500 mg given 4 times daily for 7 days.

RESULTS

Cure rates were 89% (73 of 82) in the azithromycin group and 91% (41 of 45) in the erythromycin group. A failure to respond to treatment was associated with HIV-1 seropositivity and a lack of circumcision. Both regimens were well tolerated.

CONCLUSIONS

Azithromycin, given as a single 1 g oral dose, is an effective treatment for chancroid in men, and offers major prescribing advantages over erythromycin.

Leukocyte esterase urine strips for the screening of men with urethritis--use in developing countries

BACKGROUND AND OBJECTIVES

The leukocyte esterase (LE) strip is a useful tool for the screening of men with urethritis. In developing countries, where laboratory facilities are limited, and sexually transmitted diseases endemic, simple and inexpensive diagnostic tests which perform well, would be of great value.

METHODS

Men presenting with urethritis to a referral clinic for sexually transmitted diseases in Nairobi, Kenya participated in this cohort analytical study. First-void urine was collected for LE dipstick testing as part of the diagnostic work-up. The results of the dipstick measurement were compared with the laboratory detection of Chlamydia trachomatis and Neisseria gonorrhoeae.

RESULTS

Of 200 men with symptoms of urethritis, 33 (17%) had a pathogen detected from the urethra or the urine. Chlamydia was detected in urine by PCR in 22 (11%), and gonorrhoea was cultured from the urethra in 11 (6%). Esterase activity (trace or greater) had a sensitivity of 76%, a specificity of 80%, a positive predictive value of 42% and a negative predictive value of 94% for the presence of chlamydia or gonorrhoea.

CONCLUSIONS

The use of the LE dipstick for the screening of men with symptomatic urethritis can improve diagnostic accuracy and reduce the amount of empiric antimicrobial therapy. The low detection rate of chlamydia in these men with a clinical diagnosis of nongonococcal urethritis needs further study.

Fleroxacin in the treatment of chancroid: an open study in men seropositive or seronegative for the human immunodeficiency virus type 1

Fleroxacin was prescribed to treat both HIV-negative and HIV-positive men with proven chancroid in an open study. HIV-negative men were treated with a single 400-mg dose of fleroxacin, and HIV-positive men were treated with 400 mg daily for 5 days. Three of the 58 evaluable HIV-negative men were clinical and microbiologic failures, and two of the 22 evaluable HIV-positive men had persisting infection with Haemophilus ducreyi. Both regimens were well tolerated. Fleroxacin is an acceptable alternative to existing treatment regimens for chancroid in men.

Ceftriaxone no longer predictably cures chancroid in Kenya

Ceftriaxone in a dose of 250 mg given intramuscularly is currently recommended for the treatment of chancroid. Among 133 men in Nairobi, Kenya, with culture-proven chancroid, who were treated with ceftriaxone, treatment failed in 35%. Poor outcome was associated with human immunodeficiency virus type 1 seropositivity. Thus, treatment recommendations for chancroid should be reevaluated.

Single-dose cefixime versus single-dose ceftriaxone in the treatment of antimicrobial-resistant Neisseria gonorrhoeae infection

Sexually transmitted diseases (STDs) have a significant adverse effect on reproductive and child health worldwide. The control of STDs such as gonorrhea is therefore an absolute priority. Cefixime, an oral third-generation cephalosporin with in vitro activity similar to that of ceftriaxone, may be an effective candidate for the treatment of gonorrhea. The efficacy of a single oral 400-mg dose of cefixime was compared with that of a single intramuscular 250-mg dose of ceftriaxone for the treatment of Neisseria gonorrhoeae urethritis in 190 men and cervicitis in 46 women in Nairobi, Kenya. A bacteriologic cure was recorded in 100% of 63 evaluatable patients treated with ceftriaxone and 118 (98%) of 121 evaluatable patients treated with cefixime. Cefixime, as a single oral dose, is an effective alternative for the treatment of uncomplicated gonococcal urethritis in men and cervicitis in women.

Quality control of perfusion: monitoring venous blood oxygen tension to prevent hypoxic acidosis

The long-held belief that venous oxygen tension mirrored tissue oxygen tension became suspect in the 1960s when new instrumentation consistently showed that tissue oxygen tension was 10 to 30 torr less than venous oxygen tension. Moreover, a countercurrent of oxygen exchange between terminal arteries and veins was shown to exist. Despite this conflict in scientific theory, however, monitoring venous oxygen tension as a means to control hypothermic cardiopulmonary bypass has been repeatedly urged, since myocardial acidosis is clearly extremely detrimental. This study of the relationship between venous oxygen tension during hypothermic bypass and a concurrent increment in lactacidemia yields strong objective evidence to support the use of on-line venous oxygen tension monitoring to guide perfusion. In a random series of 36 patients, venous blood samples were drawn at five preselected intervals during operation and were analyzed for pH, carbon dioxide tension, oxygen tension, lactic acid, hematocrit, and base excess. Analysis of the data revealed that venous pH and base excess showed no correlation to venous oxygen tension. However, lactic acid showed a strong correlation with venous oxygen tension, with a correlation coefficient of 0.4338 at a confidence level of p less than 0.0001. If the patients were divided into three clinically pertinent groups based on the lowest venous oxygen tension recorded, a strong relationship between venous oxygen tension and lactic acid emerged. If the lowest measurement of venous oxygen tension was greater than 35 mm Hg (group A), the mean rise in lactic acid was only 0.12 microns/ml. If the lowest measurement was between 30 and 34 mm Hg (group B), the mean rise was 0.64 microns/ml. Whereas, if any venous oxygen tension value fell below 30 mm Hg (group C), the mean rise in lactic acid was 2.56 microns/ml. Analysis of variance showed that group C values were significantly different from groups A and B values (p less than 0.0002). A scientific hypothesis relating venous oxygen tension to adequate tissue oxygenation is proposed. Use of venous oxygen tension monitoring with the goal to maintain the level above 35 mm Hg is strongly supported by this study.

The effects of changes in heart rate and aortic systolic pressure on left ventricular myocardial oxygen consumption in lambs

To determine whether changes in heart rate and aortic systolic pressure contribute equally to the determination of left ventricular myocardial oxygen consumption, we independently varied heart rate and pressure and compared the resultant oxygen consumption for similar rate-pressure products. In 6 young lambs which underwent atrioventricular node ablation, we varied heart rate by ventricular pacing at 250 beats/min, 300 beats/min, and 120 beats/min while aortic pressure remained stable and varied aortic systolic pressure by infusion of phenylephrine (to 132 +/- 15 mm Hg and 155 +/- 14 mm Hg) and by infusion of sodium nitroprusside (to 79 +/- 6 mm Hg) while heart rate was maintained stable at 200 beats/min. The 3 levels of change in aortic systolic pressure were chosen so that the ratepressure product during the pressure changes matched the rate-pressure product during the heart rate changes. We found that left ventricular myocardial oxygen consumption was the same at all 3 levels of the rate-pressure product whether heart rate was changed and pressure remained stable or pressure was changed and heart rate remained stable. Also, the correlation between oxygen consumption and the rate-pressure product was similar for both heart rate and pressure changes. During nitroprusside infusion at a fixed heart rate, oxygen extraction was significantly lower than during pacing at a heart rate of 120 beats/min when the rate-pressure product was comparable because of the direct vasodilatory effects of nitroprusside. We conclude that heart rate and aortic systolic pressure contribute equally to left ventricular myocardial oxygen consumption at the same rate-pressure product, even though there may be differences in myocardial blood flow and oxygen extraction.

Evaluation of the responsiveness of elevated pulmonary vascular resistance in children by Doppler echocardiography

Changes in the Doppler indexes, acceleration time (AcT), right ventricular ejection time (RVET), AcT/RVET ratio and pulmonary artery peak velocity were measured as were changes in pulmonary artery pressure and pulmonary vascular resistance in 21 children with pulmonary hypertension due to a large interventricular communication. In 11 children pulmonary vascular resistance was greater than 4.6 U/m2 (mean 8.6 +/- 1.6), whereas in 10 it was less than 4.5 U/m2 (mean 3.4 +/- 0.2). Although both groups demonstrated acceleration time and AcT/RVET values above normal, there were no significant differences in these values between the groups with high and low pulmonary vascular resistance. With administration of a pulmonary vasodilator pulmonary vascular resistance decreased in 11 responders by greater than 50% of baseline values (from 5.3 +/- 0.7 to 1.6 +/- 0.3 U/m2), whereas in the 10 nonresponders mean pulmonary vascular resistance decreased from 7.0 +/- 1.9 to 4.9 +/- 1.1 U/m2. There was no significant change in the Doppler indexes except for an increase in pulmonary artery peak velocity in the responders from 1.34 +/- 0.07 to 1.66 +/- 0.06 m/s (p less than 0.001). The results indicate that Doppler echocardiography cannot predict either the level of increased pulmonary vascular resistance or the degree of responsiveness sufficiently to obviate the need for cardiac catheterization in patients with interventricular communication and pulmonary hypertension.

Inhibition of human cytomegalovirus by trifluorothymidine

The antiviral activity of trifluorothymidine (TFT) singly and in combination with other antiviral agents against human cytomegalovirus (HCMV) was evaluated by using an infectious center plaque reduction assay. The 50% inhibitory dose of TFT against six different patient HCMV strains was 0.57 (+/- 0.24, standard deviation) microM and ranged from 0.32 to 0.97 microM. The 50% inhibitory dose for the laboratory-adapted HCMV strain, AD-169, was 2.1 microM. When TFT (0.17 microM) was combined with human fibroblast interferon (25 U/ml), the combination was additive against all four HCMV isolates evaluated. Synergism was observed when TFT (0.17 microM) was combined with phosphonoformic acid (25 microM) for all strains studied or with acyclovir (20 microM) for three of the four clinical HCMV strains tested. Each of the three antiviral agents, when combined with TFT, exhibited additive effects against strain AD-169. TFT at concentrations of 0.5, 1.7, and 3.5 microM had an increasing inhibitory effect on uninfected human embryonic lung fibroblast (HEL) cell growth over 72 h, with 16% growth inhibition at 3.5 microM after 3 days. There was no increased toxicity to growing HEL cells when the paired antiviral agent combinations were evaluated. These findings suggest that TFT may be useful singly or in combination with other antiviral agents in treating HCMV infections.

Effects of acyclovir combined with other antiviral agents on human cytomegalovirus

At present, there is no effective therapy for human cytomegalovirus (CMV) infections. Although acyclovir inhibits in vitro clinical isolates of CMV, preliminary human trials suggest that acyclovir may not be successful as a single antiviral agent in treating CMV infections. The antiCMV activity of acyclovir in combination with human fibroblast interferon (IFN-beta), phosphonoformic acid (PFA), or trifluorothymidine (TFT) was therefore evaluated. When acyclovir (20 microM) was combined with IFN-beta (25 U/ml), additive antiviral effects were observed for the four clinical CMV isolates studied and the laboratory adapted strain, AD-169. The combination of acyclovir (20 microM) with PFA (25 microM) was synergistic for all four clinical isolates studied, but additive for the AD-169 strain. Similarly, the combination of acyclovir (20 microM) and TFT (0.17 microM) was synergistic for three of four clinical isolates, and additive for one clinical strain and the AD-169 virus. These findings suggest that acyclovir combined with other antiviral agents may be useful in the treatment of CMV disease.