Single-dose treatment of cholera with furazolidone or tetracycline in a double-blind randomized trial

Strategies to Prevent Cholera Introduction during International Personnel Deployments: A Computational Modeling Analysis Based on the 2010 Haiti Outbreak

BACKGROUND

Introduction of Vibrio cholerae to Haiti during the deployment of United Nations (UN) peacekeepers in 2010 resulted in one of the largest cholera epidemics of the modern era. Following the outbreak, a UN-commissioned independent panel recommended three pre-deployment intervention strategies to minimize the risk of cholera introduction in future peacekeeping operations: screening for V. cholerae carriage, administering prophylactic antimicrobial chemotherapies, or immunizing with oral cholera vaccines. However, uncertainty regarding the effectiveness of these approaches has forestalled their implementation by the UN. We assessed how the interventions would have impacted the likelihood of the Haiti cholera epidemic.

METHODS AND FINDINGS

We developed a stochastic model for cholera importation and transmission, fitted to reported cases during the first weeks of the 2010 outbreak in Haiti. Using this model, we estimated that diagnostic screening reduces the probability of cases occurring by 82% (95% credible interval: 75%, 85%); however, false-positive test outcomes may hamper this approach. Antimicrobial chemoprophylaxis at time of departure and oral cholera vaccination reduce the probability of cases by 50% (41%, 57%) and by up to 61% (58%, 63%), respectively. Chemoprophylaxis beginning 1 wk before departure confers a 91% (78%, 96%) reduction independently, and up to a 98% reduction (94%, 99%) if coupled with vaccination. These results are not sensitive to assumptions about the background cholera incidence rate in the endemic troop-sending country. Further research is needed to (1) validate the sensitivity and specificity of rapid test approaches for detecting asymptomatic carriage, (2) compare prophylactic efficacy across antimicrobial regimens, and (3) quantify the impact of oral cholera vaccine on transmission from asymptomatic carriers.

CONCLUSIONS

Screening, chemoprophylaxis, and vaccination are all effective strategies to prevent cholera introduction during large-scale personnel deployments such as that precipitating the 2010 Haiti outbreak. Antimicrobial chemoprophylaxis was estimated to provide the greatest protection at the lowest cost among the approaches recently evaluated by the UN.

Antimicrobial drugs for treating cholera

BACKGROUND

Cholera is an acute watery diarrhoea caused by infection with the bacterium Vibrio cholerae, which if severe can cause rapid dehydration and death. Effective management requires early diagnosis and rehydration using oral rehydration salts or intravenous fluids. In this review, we evaluate the additional benefits of treating cholera with antimicrobial drugs.

OBJECTIVES

To quantify the benefit of antimicrobial treatment for patients with cholera, and determine whether there are differences between classes of antimicrobials or dosing schedules.

SEARCH METHODS

We searched the Cochrane Infectious Disease Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; African Index Medicus; LILACS; Science Citation Index; metaRegister of Controlled Trials; WHO International Clinical Trials Registry Platform; conference proceedings; and reference lists to March 2014.

SELECTION CRITERIA

Randomized and quasi-randomized controlled clinical trials in adults and children with cholera that compared: 1) any antimicrobial treatment with placebo or no treatment; 2) different antimicrobials head-to-head; or 3) different dosing schedules or different durations of treatment with the same antimicrobial.

DATA COLLECTION AND ANALYSIS

Two reviewers independently applied inclusion and exclusion criteria, and extracted data from included trials. Diarrhoea duration and stool volume were defined as primary outcomes. We calculated mean difference (MD) or ratio of means (ROM) for continuous outcomes, with 95% confidence intervals (CI), and pooled data using a random-effects meta-analysis. The quality of evidence was assessed using the GRADE approach.

MAIN RESULTS

Thirty-nine trials were included in this review with 4623 participants. Antimicrobials versus placebo or no treatment Overall, antimicrobial therapy shortened the mean duration of diarrhoea by about a day and a half compared to placebo or no treatment (MD -36.77 hours, 95% CI -43.51 to -30.03, 19 trials, 1013 participants, moderate quality evidence). Antimicrobial therapy also reduced the total stool volume by 50% (ROM 0.5, 95% CI 0.45 to 0.56, 18 trials, 1042 participants, moderate quality evidence) and reduced the amount of rehydration fluids required by 40% (ROM 0.60, 95% CI 0.53 to 0.68, 11 trials, 1201 participants, moderate quality evidence). The mean duration of fecal excretion of vibrios was reduced by almost three days (MD 2.74 days, 95% CI -3.07 to -2.40, 12 trials, 740 participants, moderate quality evidence).There was substantial heterogeneity in the size of these benefits, probably due to differences in the antibiotic used, the trial methods (particularly effective randomization), and the timing of outcome assessment. The benefits of antibiotics were seen both in trials recruiting only patients with severe dehydration and in those recruiting patients with mixed levels of dehydration. Comparisons of antimicrobials In head-to-head comparisons, there were no differences detected in diarrhoea duration or stool volume for tetracycline compared to doxycycline (three trials, 230 participants, very low quality evidence); or tetracycline compared to ciprofloxacin or norfloxacin (three trials, 259 participants, moderate quality evidence). In indirect comparisons with substantially more trials, tetracycline appeared to have larger benefits than doxycycline, norfloxacin and trimethoprim-sulfamethoxazole for the primary review outcomes.Single dose azithromycin shortened the duration of diarrhoea by over a day compared to ciprofloxacin (MD -32.43, 95% CI -62.90 to -1.95, two trials, 375 participants, moderate quality evidence) and by half a day compared to erythromycin (MD -12.05, 95% CI -22.02 to -2.08, two trials, 179 participants, moderate quality evidence). It was not compared with tetracycline.

AUTHORS' CONCLUSIONS

In treating cholera, antimicrobials result in substantial improvements in clinical and microbiological outcomes, with similar effects observed in severely and non-severely ill patients. Azithromycin and tetracycline may have some advantages over other antibiotics.

VceR negatively regulates the vceCAB MDR efflux operon and positively regulates its own synthesis in Vibrio cholerae 569B

The vceCAB (vce) operon encodes the multidrug resistance pump VceCAB (VCE), which contributes to resistance of Vibrio cholerae to carbonyl cyanide m-chlorophenylhydrazine (CCCP), deoxycholate, and pentachlorophenol by several-fold. vceR, which encodes the TetR-type repressor VceR and is divergently transcribed from vce, has been characterized in Escherichia coli. Detailed characterization of vceR in V. cholerae 569B confirmed the repressive effect of VceR on VCE function and indicated several novel features of VceR. Deletion of vceR increased resistance of strain 569B to CCCP and deoxycholate modestly, but did not affect resistance to pentachlorophenol. Transcriptional analysis revealed that vce expression was not only increased in strain 569BDeltavceR::Omega by 2-fold but continued to rise throughout the growth cycle. Using a vceR-lux transcriptional fusion plasmid, we examined whether vceR is autoregulated in strain 569B. Expression of vceR from the vceR-lux fusion was significantly lower in strain 569BDeltavceR::Omega than in strain 569B. In addition, exposure to CCCP reduced vceR expression from the vceR-lux fusion in strain 569B but not in strain 569BDeltavceR::Omega. Despite differences in the VceR binding site in strain 569B from the previously recognized 28 bp sequence in V. cholerae CVD101, purified recombinant VceR bound to the 24 bp sequence from strain 569B. We propose that VceR modulates vce expression by binding in vivo to the 24 bp sequence within the vceR-vce intergenic region; unlike many TetR repressors that are negatively autoregulated, VceR positively regulates vceR expression in trans.

Single-dose azithromycin for the treatment of cholera in adults

BACKGROUND

Single-dose azithromycin is effective in the treatment of severe cholera in children, but its effectiveness in adults has not been evaluated.

METHODS

We conducted a double-blind, randomized trial comparing the equivalence of azithromycin and ciprofloxacin (each given in a single 1-g dose of two 500-mg tablets) among 195 men with severe cholera caused by Vibrio cholerae O1 or O139. Patients were hospitalized for five days. A stool culture was performed daily. Primary outcome measures were clinical success (the cessation of watery stools within 48 hours after drug administration) and bacteriologic success (the inability to isolate V. cholerae after 48 hours).

RESULTS

Therapy was clinically successful in 71 of 97 patients receiving azithromycin (73 percent) and in 26 of 98 patients receiving ciprofloxacin (27 percent) (P<0.001) and bacteriologically successful in 76 of 97 patients receiving azithromycin (78 percent) and in 10 of 98 patients receiving ciprofloxacin (10 percent) (P<0.001). Patients who were treated with azithromycin had a shorter duration of diarrhea than did patients treated with ciprofloxacin (median, 30 vs. 78 hours); a lower frequency of vomiting (43 percent vs. 67 percent); fewer stools (median, 36 vs. 52); and a lower stool volume (median, 114 vs. 322 ml per kilogram of body weight). The median minimal inhibitory concentration of ciprofloxacin for the 177 isolates of V. cholerae O1 was 0.25 mug per milliliter, which was 11 to 83 times as high as that in previous studies at this site.

CONCLUSIONS

Single-dose azithromycin was effective in the treatment of severe cholera in adults. The lack of efficacy of ciprofloxacin may result from its diminished activity against V. cholerae O1 strains currently circulating in Bangladesh. (ClinicalTrials.gov number, NCT00229944.).

Small-molecule inhibitor of Vibrio cholerae virulence and intestinal colonization

Increasing antibiotic resistance requires the development of new approaches to combating infection. Virulence gene expression in vivo represents a target for antibiotic discovery that has not yet been explored. A high-throughput, phenotypic screen was used to identify a small molecule 4-[N-(1,8-naphthalimide)]-n-butyric acid, virstatin, that inhibits virulence regulation in Vibrio cholerae. By inhibiting the transcriptional regulator ToxT, virstatin prevents expression of two critical V. cholerae virulence factors, cholera toxin and the toxin coregulated pilus. Orogastric administration of virstatin protects infant mice from intestinal colonization by V. cholerae.

Single-dose ciprofloxacin versus 12-dose erythromycin for childhood cholera: a randomised controlled trial

BACKGROUND

Single-dose ciprofloxacin is effective for the treatment of severe cholera in adults. We assessed whether single-dose ciprofloxacin would be as effective as 3-day, 12-dose erythromycin in achieving clinical cure in children with severe cholera.

METHODS

We did a randomised, open label, controlled trial in children age 2-15 years with V cholerae O1 or O139 present in stool on dark-field microscopy. Children received either a single 20 mg/kg dose of ciprofloxacin (n=90) or 12.5 mg/kg of erythromycin (n=90) every 6 h for 3 days, and remained in hospital for 5 days. The primary outcome was clinical success of treatment, defined as cessation of watery stools within 48 h of start of drug treatment. Analysis was per protocol. This study is registered with the ClinicalTrials.gov Protocol Registration System at http://www.clinicaltrials.gov (registration number NCT 00142272) [corrected]

FINDINGS

Of 180 children randomised 162 completed the study. Treatment was clinically successful in 60% (47/78) of children treated with ciprofloxacin and in 55% (46/84) of those treated with erythromycin (difference 5% [95% CI -10 to 21]). Children receiving ciprofloxacin vomited less often (58%vs 74%; difference 16% [2 to 30]), had fewer stools (15 vs 21; 6 [0 to 9]), and less stool volume (152 vs 196 mL/kg; 43 mL/kg [13 to 87]) than those receiving erythromycin. Bacteriological failure was more common in ciprofloxacin-treated patients (58%vs 30%; 28% [13 to 43]) than erythromycin-treated patients.

INTERPRETATION

Single-dose ciprofloxacin achieves clinical outcomes similar to, or better than, those achieved with 12-dose erythromycin treatment in childhood cholera, but is less effective in eradicating V cholerae from stool.

Destroying the Life and Career of a Valued Physician-Scientist Who Tried to Protect Us from Plague: Was It Really Necessary?

Thomas Campbell Butler, at 63 years of age, is completing the first year of a 2-year sentence in federal prison, following an investigation and trial that was initiated after he voluntarily reported that he believed vials containing Yersinia pestis were missing from his laboratory at Texas Tech University. We take this opportunity to remind the infectious diseases community of the plight of our esteemed colleague, whose career and family have, as a result of his efforts to protect us from infection by this organism, paid a price from which they will never recover.

Comparison of single-dose azithromycin and 12-dose, 3-day erythromycin for childhood cholera: a randomised, double-blind trial

BACKGROUND

Cholera is a major public-health problem, with children most affected. However, effective single-dose antimicrobial regimens have been identified only for adults. Our aim was to compare the efficacy of azithromycin and erythromycin regimens in the treatment of children.

METHODS

We did a double-blind, randomised study of 128 severely dehydrated children (age 1-15 years) with cholera, treated at one of two treatment centres in Bangladesh in 1999. Children were assigned single-dose azithromycin (20 mg/kg bodyweight, maximum individual dose 1 g; n=65) or 12.5 mg/kg erythromycin (maximum dose 500 mg; n=63) every 6 h for 3 days. Patients stayed in hospital for 5 days. We measured fluid balance every 6 h, and obtained a rectal swab or stool sample for culture daily. Our primary outcome measures were clinical success of treatment-ie, cessation of watery diarrhoea within 48 h-and bacteriological success-ie, absence of Vibrio cholerae O1 or O139 from cultures of stool or rectal swab samples after study day 2. Analysis was per protocol.

FINDINGS

Two children in both groups withdrew from the study, and we excluded one child in the erythromycin group. Treatment was clinically successful in 48 (76%) patients who received azithromycin and 39 (65%) who received erythromycin (difference 11%, 95% CI -5 to 27, p=0.244); and bacteriologically successful in 45 (71%) and 49 (82%) patients, respectively (10%, -5 to 25, p=0.261). Patients treated with azithromycin had a shorter duration of diarrhoea (median 24 h vs 42 h; difference 12 h, 0-18 h, p=0.019) and fewer episodes of vomiting (1 vs 4; difference 1 episode, 0-3 episodes, p=0.023).

INTERPRETATION

Single-dose azithromycin is as effective for treatment of cholera in children as standard erythromycin therapy, but is associated with less vomiting.

Randomised controlled comparison of single-dose ciprofloxacin and doxycycline for cholera caused by Vibrio cholerae 01 or 0139

BACKGROUND

Effective antimicrobial therapy can reduce the duration and volume of cholera diarrhoea by half. However, such treatment is currently limited by Vibrio cholerae resistance to the drugs commonly prescribed for cholera, and by the difficulties involved in the administration of multi-drug doses under field conditions. Because of its favourable pharmacokinetics we thought it likely that single-dose ciprofloxacin would be effective in the treatment of cholera.

METHODS

In this double-blind study treatment was either a single 1 g oral dose of ciprofloxacin plus doxycycline placebo, or a single 300 mg oral dose of doxycycline plus ciprofloxacine placebo. 130 moderately or severely dehydrated men infected with V cholerae 01 and 130 infected with V cholerae 0139 were randomly assigned treatment. Patients stayed in hospital for 5 days. We measured fluid intake and stool volume every 6 h, and a sample of stool for culture was obtained daily. The primary outcome measures were clinical success--the cessation of watery stool within 48 h; and bacteriological success--absence of V cholerae from cultures of stool after study day 2.

FINDINGS

Among patients infected with V cholerae 01, treatment was clinically successful in 62 (94%) of 66 patients who received ciprofloxacin and in 47 (73%) of 64 who receive doxycycline (difference 21% [95% Cl 8-33]); the corresponding proportions with bacteriological success were 63 (95%) and 44 (69%) (27% [14-39]). Among patients infected with V cholerae 0139, treatment was clinically successful in 54 (92%) of 59 patients who received ciprofloxacin and in 65 (92%) of 71 who received doxycycline (< 1% [-9 to 9]), and bacteriologically successful in 58 (98%) and 56 (79%), respectively (19% [9-30]). Total volume of watery stool did not differ significantly between ciprofloxacin-group and doxycycline-group patients infected with either V cholerae 01 or 0139. All but one of the V cholerae 01 and all of the 0139 isolates were susceptible in vitro to doxycycline, whereas 48 (37%) of the V cholerae 01 isolates and none of the 0139 isolates were resistant to tetracycline. Treatment clinically failed in 14 (52%) of 27 doxycycline-treated patients infected with a tetracycline-resistant V cholerae 01 strain, compared with three (8%) of 37 patients infected with a tetracycline-susceptible strain (44% [23-65]).

INTERPRETATION

Single-dose ciprofloxacin is effective in the treatment of cholera caused by V cholerae 01 or 0139 and is better than single-dose doxycycline in the eradication of V cholerae from stool. Single-dose ciprofloxacin may also be the preferred treatment in areas where tetracycline-resistant V cholerae are common. In V cholerae, in-vitro doxycycline susceptibilities are not a useful indicator of the in-vivo efficacy of the drug.

Norfloxacin monodose use in patients with cholera in Salta Argentina

The use of monodose (800 mg) per os of Norfloxacin was evaluated in 32 patients with cholera at Salvador Mazza's Hospital, Salta, Argentina. It was considered the celerity in negativization of stool culture (100% of cases: 12 hours post administration), it efficiency along time (24/24 controlled patients were negative at 10th day) and MIC of isolated strains (100% of strains were sensitive: range 0.008 to 0.016 micrograms/ml). It was included oral administration of sorbitol 70% in peanut oil in order to study patients at 10th day's control. This method could be an alternative one in the study of asymptomatic carrier. Norfloxacin monodose shows good performance in early negativization of stool culture and it was also effective along the whole observation period, suggesting it could prevent carriage.

Comparative trial of five antimicrobial compounds in the treatment of cholera in adults

To compare the efficacy of ciprofloxacin, erythromycin, nalidixic acid and pivmecillinam in the treatment of tetracycline-resistant strains of Vibrio cholerae O1 in adults, a randomized, open, clinical trial was conducted. A tetracycline group was used for comparison. Seventy-five adult men infected with V. cholerae O1 were randomly assigned to receive either 400 mg pivmecillinam or 500 mg of one of each of the other drugs. Ciprofloxacin was given every 12 h and the others every 6 h for 3 d. The mean total stool volume per kg was 155 mL for the ciprofloxacin group, 212 mL for the erythromycin and pivmecillinam groups, 246 mL for nalidixic acid, and 293 mL for tetracycline. The difference between ciprofloxacin and tetracycline was significant (P = 0.045). After 72 h, diarrhoea had stopped in 14 patients (93%) in the ciprofloxacin group and 12 (80%) in the erythromycin group, compared to 5 (42%) of those receiving tetracycline (P = 0.006 and 0.049, respectively). Bacteriological clearance was 100% at 24 h in patients treated with ciprofloxacin compared to 20% and 8.3% (P < 0.001 for both comparisons) in the erythromycin and tetracycline groups. Ciprofloxacin in conjunction with appropriate fluid therapy was the most effective treatment for cholera in adults; erythromycin was the next best.

Cholera vaccination: a decision analysis

OBJECTIVE

To examine the clinical impact and financial cost of a vaccination program for the prevention of cholera in North Americans travelling to endemic and epidemic regions by means of the principles of decision analysis and a decision tree as well as to illustrate the effect of case attack rates on the cost per case prevented by vaccination.

DESIGN

Review of the scientific literature to establish the probabilities of each significant outcome as well as a decision analysis and partial economic evaluation.

OUTCOME MEASURES

Clinical impact (attack rates for cholera among vaccinated and nonvaccinated travellers), rates of death associated with cholera and vaccine-associated adverse events (VAAEs), and the number of VAAEs and the vaccine cost per case prevented.

MAIN RESULTS

On the basis of our assumptions (including a rate of one case of cholera per 500,000 journeys to endemic regions), to prevent one case of cholera a vaccination program would cost $28.67 million and be associated with 105 VAAEs.

CONCLUSION

Routine vaccination of travellers to endemic areas cannot be recommended; however, for people travelling to regions with a high transmission rate vaccination should be considered.

Efficacy of a single dose of furazolidone for treatment of cholera in children

To test the efficacy and safety of furazolidone given as a single dose for childhood cholera, a randomized double-blind placebo-controlled trial was carried out among 118 culture-positive dehydrated children with diarrhea. Patients were randomly assigned to one of four groups to receive medication orally in liquid suspension: furazolidone at 7 mg/kg/day once, furazolidone at 7 mg/kg/day divided into four doses for 3 days, placebo once, or placebo for 3 days. After 12 patients with furazolidone-resistant infections were excluded from the analysis of efficacy, it was determined that both groups treated with furazolidone showed significantly higher rates of bacteriologic success (stool cultures negative for Vibrio cholerae on days 2 to 4 after start of therapy) and clinical success (cessation of diarrhea within 72 h after start of therapy) than corresponding placebo groups (P less than 0.001). There were no significant differences between responses to the 3-day and single-dose regimens of furazolidone, but there was a trend toward better clinical responses in patients who received furazolidone for 3 days. No patient treated with furazolidone dropped out because of side effects. These results indicate that furazolidone, given as either a single dose or divided doses for 3 days, is effective treatment for childhood cholera.