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

Genomic insights into the 2022-2023Vibrio cholerae outbreak in Malawi

Malawi experienced its deadliest Vibrio cholerae (Vc) outbreak following devastating cyclones, with >58,000 cases and >1700 deaths reported between March 2022 and May 2023. Here, we use population genomics to investigate the attributes and origin of the Malawi 2022-2023 Vc outbreak isolates. Our results demonstrate the predominance of ST69 clone, also known as the seventh cholera pandemic El Tor (7PET) lineage, expressing O1 Ogawa (~ 80%) serotype followed by Inaba (~ 16%) and sporadic non-O1/non-7PET serogroups (~ 4%). Phylogenetic reconstruction revealed that the Malawi outbreak strains correspond to a recent importation from Asia into Africa (sublineage AFR15). These isolates harboured known antimicrobial resistance and virulence elements, notably the ICEGEN/ICEVchHai1/ICEVchind5 SXT/R391-like integrative conjugative elements and a CTXφ prophage with the ctxB7 genotype compared to historical Malawian Vc isolates. These data suggest that the devastating cyclones coupled with the recent importation of 7PET serogroup O1 strains, may explain the magnitude of the 2022-2023 cholera outbreak in Malawi.

Pharmacoinformatics and molecular dynamics simulation approach to identify anti-diarrheal potentials of Centella asiatica (L.) Urb. against Vibrio cholerae

Vibrio cholerae, the etiological agent of cholera, causes dehydration and severe diarrhea with the production of cholera toxin. Due to the acquired antibiotic resistance, V. cholerae has drawn attention to the establishment of novel medications to counteract the virulence and viability of the pathogen. Centella asiatica is a medicinal herb native to Bangladesh that has a wide range of medicinal and ethnobotanical applications including anti-bacterial properties. In the present investigation, a total of 25 bioactive phytochemicals of C. asiatica have been screened virtually through molecular docking, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) analyses, and molecular dynamics simulation. Our results revealed four lead compounds as Viridiflorol (-8.7 Kcal/mol), Luteolin (-8.1 Kcal/mol), Quercetin (-8.0 Kcal/mol) and, Geranyl acetate (-7.1 Kcal/mol) against V. cholerae Toxin co-regulated pilus virulence regulatory protein (ToxT). All the lead compounds have been found to possess favorable pharmacokinetic, pharmacodynamics, and molecular dynamics properties. Toxicity analysis revealed satisfactory results with no major side effects. Molecular dynamics simulation was performed for 100 ns that revealed noteworthy conformational stability and structural compactness for all the lead compounds, especially for Quercetin. Target class prediction unveiled enzymes in most of the cases and some experimental and investigational drugs were found as structurally similar analogs of the lead compounds. These findings could aid in the development of novel therapeutics targeting Cholera disease and we strongly recommend in vitro trials of our experimental findings.Communicated by Ramaswamy H. Sarma.

Antibacterial, antibiofilm, and antimotility signatures of some natural antimicrobials against Vibrio cholerae

Vibrio cholerae is an etiological cause of cholera and has been implicated in several epidemics. Exploration of the antimicrobial signatures of culinary spices has become an important industrial tool to suppress the growth of foodborne bacterial pathogens including Vibrio spp. The antibiofilm and antimotility activities of some selected natural antimicrobial agents were then evaluated. All the extracts showed vibriostatic activities with minimum inhibitory concentration (MIC) ranging from 0.1% to 0.4%. Cinnamon and black pepper demonstrated significant biofilm inhibition activity from 94.77% to 99.77% when administered at 100% MIC. Black pepper extract also demonstrated the highest biofilm inhibition activity against the established biofilms of V. cholerae O1 and O139. Cinnamon, calabash nutmeg, and black pepper significantly inhibited swimming and swarming motility by 85.51% to 94.87%. Sub-MICs (50% and 75%) of some extracts were also effective as an antibiofilm and antimotility agent against the tested strains. The findings of our study suggest the potential application of natural antimicrobial agents such as spices in food to inhibit biofilm formation and motility, which consequently mitigate the virulence and persistence of the pathogen in the food supply chain.

Changing Susceptibility Pattern of Vibrio cholerae O1 Isolates to Commonly Used Antibiotics in the Largest Diarrheal Disease Hospital in Bangladesh during 2000-2018

The efficacy of commonly used antibiotics for treating severe cholera has been compromised over time because of the reduced antibiotic susceptibility. This study aimed to describe the rate of detection of Vibrio cholerae O1 from fecal samples and antimicrobial susceptibility profiles of V. cholerae O1 serotypes to commonly used antibiotics. During January 2000-December 2018, V. cholerae O1 was detected in fecal samples of 7,472 patients. Vibrio cholerae O1 Inaba serotype was predominant, ranging from 60% to 86% during the period 2000-2006 except for 2003 and 2005 when the Ogawa serotype was predominant. Later on, the Ogawa serotype became predominant from 2007 to 2015, fluctuating between 52% and 100%. However, in 2016 and 2017, isolation rates declined to 2% and 1%, respectively, but surged again to 75% in 2018. Nearly 100% of V. cholerae O1 strains were sensitive to tetracycline during 2000-2004. Thereafter, a declining trend of sensitivity was observed to be continued and dropped down to < 6% during 2012-2017 and again increased to 76% in 2018. Susceptibility to azithromycin and ciprofloxacin was nearly 100%, and susceptibility to cotrimoxazole and furazolidone was 01% throughout the study period. We also found the emergence of resistance to erythromycin in 2005 and sensitivity to cotrimoxazole in 2018. Thus, the rapid decline of the sensitivity of V. cholerae O1 to tetracycline and a reversed peak after 6 years need continued monitoring and reporting.

Guidelines for the management of paediatric cholera infection: a systematic review of the evidence

Background Vibrio cholerae is a highly motile Gram-negative bacterium which is responsible for 3 million cases of diarrhoeal illness and up to 100,000 deaths per year, with an increasing burden documented over the past decade. Current WHO guidelines for the treatment of paediatric cholera infection (tetracycline 12.5 mg/kg four times daily for 3 days) are based on data which are over a decade old. In an era of increasing antimicrobial resistance, updated review of the appropriate empirical therapy for cholera infection in children (taking account of susceptibility patterns, cost and the risk of adverse events) is necessary. Methods A systematic review of the current published literature on the treatment of cholera infection in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was undertaken. International clinical guidelines and studies pertaining to adverse effects associated with treatments available for cholera infection were also reviewed. Results The initial search produced 256 results, of which eight studies met the inclusion criteria. Quality assessment of the studies was performed as per the Grading of Recommendations Assessment, Development and Evaluation guidelines. Conclusions In view of the changing non-susceptibility rates worldwide, empirical therapy for cholera infection in paediatric patients should be changed to single-dose azithromycin (20 mg/kg), a safe and effective medication with ease of administration. Erythromycin (12.5 mg/kg four times daily for 3 days) exhibits similar bacteriological and clinical success and should be listed as a second-line therapy. Fluid resuscitation remains the cornerstone of management of paediatric cholera infection, and prevention of infection by promoting access to clean water and sanitation is paramount.

Role of antimicrobials in the treatment of adult patients presenting to the emergency department with acute gastroenteritis - A mini review

BACKGROUND & OBJECTIVE

Acute gastroenteritis is generally considered a self-limiting illness that does not require the use of antibiotics. However, many emergency departments in the country frequently prescribe antibiotics to patients presenting with diarrhoea. This review attempts to determine whether this practice is reasonable. Our objective was to determine the role of antimicrobials in the empiric management of acute gastroenteritis.

METHODS

The online data base "PubMed", as well as the World Wide Web, were searched for relevant articles (RCTs, Reviews, Prospective studies, etc.) with key words such as "gastroenteritis AND antibiotics", "Management AND gastroenteritis", "Treatment AND diarrhoea" etc. and covered the years 1960-2016. Fifty articles were studied, of which 43 were chosen on the basis of relevance for qualitative assessment.

RESULTS

The articles reviewed for this paper suggest that antimicrobial therapy is not appropriate for the majority of cases of (uncomplicated) gastroenteritis, as risks (antibiotic-associated diarrhoea, hypersensitivity reactions, etc.) outweigh benefits. However, there are instances where antibiotics are clearly indicated. Further, it is noted that there have not been any recent trials to clarify the role of antimicrobials in adult diarrhoeal illness.

CONCLUSIONS

The focus in management of patients presenting with diarrhoea in the Emergency Department should be on rehydration and that only certain patients, such as those with fever or dysentery, or those with an impaired immune response should receive empiric antimicrobial therapy. More studies are needed to determine in what instances antimicrobials are of greatest benefit, so that adverse effects of rampant antibiotic prescription can be curtailed.

Efficacy of Ciprofloxacin for Treatment of Cholera Associated with Diminished Susceptibility to Ciprofloxacin to Vibrio cholerae O1

Objective

We identified a poor clinical response to treatment of cholera with a single 1 g dose of ciprofloxacin, a standard treatment for cholera.

Methods

To determine reasons for the poor response and better therapeutic approaches we examined the minimal inhibitor concentration (MIC, n = 275) and disc-diffusion zone sizes (n = 205) for ciprofloxacin and nalidixic acid of V. cholerae O1 strains isolated in Bangladesh from 1994 to 2012, and reexamined data from 161patients infected with Vibrio cholerae O1 recruited in four clinical trials who received single- or multiple-dose ciprofloxacin for treatment of cholera and compared their clinical response to the V. cholerae O1 susceptibility.

Results

Although all 275 isolates of V. cholerae O1 remained susceptible to ciprofloxacin using standard MIC and disc-diffusion thresholds, the MIC⁹⁰ to ciprofloxacin increased from 0.010 in 1994 to 0.475 μgm/ml in 2012. Isolates became frankly resistant to nalidixic with the MIC⁹⁰ increasing from 21 μgm/ml in 1994 to >256 μgm/ml and 166 of 205 isolates from 1994 to 2005 being frankly resistant using disc-diffusion testing. Isolates resistant to nalidixic acid by disc-diffusion testing had a median ciprofloxacin MIC of 0.190 μgm/ml (10^th-90^th centiles 0.022 to 0.380); nalidixic acid-susceptible isolates had a median ciprofloxacin MIC of 0.002 (0.002 to 0.012).The rate of clinical success with single-dose ciprofloxacin treatment for nalidixic acid-susceptible strains was 94% (61 of 65 patients) and bacteriologic success 97% (63/65) compared to 18% (12/67) and 8% (5/67) respectively with nalidixic acid-resistant strains (P<0.001 for both comparisons). Multiple-dose treatment with ciprofloxacin had 86% and 100% clinical and bacteriologic success rates respectively in patients infected with nalidixic acid-susceptible strains of V. cholerae O1 compared to clinical success 67% and bacteriologic success 60% with nalidixic acid-resistant strains.

Conclusions

Single-dose ciprofloxacin is not effective for treating cholera caused by V. cholerae O1 with diminished susceptibility to ciprofloxacin, and nalidixic acid disc-diffusion testing effectively screens for such isolates.

Meddling Vibrio cholerae Murmurs: A Neoteric Advancement in Cholera Research

Cholera, a known diarrheal disease is associated with various risk factors like hypovolemic shock, rice watery stools, and death in developing countries. The overuse of antibiotics to treat cholera imposed a selective pressure for the emergence and spread of multi-drug resistant Vibrio cholerae strains. The failure of conventional antimicrobial therapy urged the researchers to find an alternative therapy that could meddle the cholera murmurs (Quorum Sensing). It seems to effectively overcome the conventional cholera therapies in parallel to decrease the morbidity and mortality rate in the developing countries. The paramount objective of this review essentially focuses on the different Quorum Sensing (QS) regulatory switches governing virulence and pathogenicity of Vibrio cholerae. This review also provides an insight into the plausible QS targets that could be exploited to bring about a breakthrough to the prevailing cholera therapy.

[Drug therapy of infectious diarrhea: part 1: acute diarrhea]

BACKGROUND

Diarrhea is one of the most commonly occurring diseases.

AIM

This article gives a review of the current state of the treatment of acute infectious diarrhea (part 1) and chronic infectious diarrhea (part 2) as well as of the most important pathogens.

MATERIAL AND METHODS

Following a presentation of the general principles of the therapy of diarrhea, the targeted antimicrobial therapy of the most important bacterial gastrointestinal infections is described. This includes salmonellosis, shigellosis and Campylobacter infections, infections with pathogenic Escherichia coli strains, yersiniosis and cholera. Due to the increasing incidence and changes in the severity of the disease and important new aspects in the treatment of diarrhea caused by toxigenic Clostridium difficile strains, these disease entities will be described in detail.

RESULTS

Symptomatic therapy is still the most important aspect of the treatment of infectious diarrhea. For severely ill patients with a high frequency of stools (> 8/day), immunodeficiency, advanced age or significant comorbidities, empirical antibiotic therapy should be considered. Increasing resistance, in particular against fluoroquinolones must also be taken into consideration. Due to the risk of excessive pathogen proliferation and concomitant intestinal toxin production with protracted or multiple complications during the disease, therapy with motility inhibitors is not recommended. With respect to the treatment of Clostridium difficile infections a promising novel aspect arose in 2012. The macrocyclic antibiotic fidaxomycin can reduce the rate of recurrent disease with the same effectiveness as vancomycin. Furthermore, evidence for the benefits of allogenic stool transplantation is increasing.

CONCLUSION

The treatment of acute diarrhea is still primarily supportive. The benefits of general empirical antibiotic therapy for acute diarrhea are not evidence-based.

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.

Discovery and biological characterization of the auromomycin chromophore as an inhibitor of biofilm formation in Vibrio cholerae

Bacterial biofilms pose a significant challenge in clinical environments due to their inherent lack of susceptibility to antibiotic treatment. It is widely recognized that most pathogenic bacterial strains in the clinical setting persist in the biofilm state, and are the root cause of many recrudescent infections. The discovery and development of compounds capable of either inhibiting biofilm formation or initiating biofilm dispersal might provide new therapeutic avenues for reducing the number of hospital-acquired, biofilm-mediated infections. We detail here the application of our recently reported image-based, high-throughput screen to the discovery of microbially derived natural products with inhibitory activity against Vibrio cholerae biofilm. Examination of a prefractionated library of microbially derived marine natural products has led to the identification of a new biofilm inhibitor that is structurally unrelated to previously reported inhibitors and is one of the most potent inhibitors of V. cholerae reported to date. Combination of this compound with sub-MIC concentrations of a number of clinically relevant antibiotics was shown to improve the inhibitory efficacy of this new compound compared to monotherapy treatments, and provides evidence for the potential therapeutic benefit of biofilm inhibitors in treating persistent biofilm-mediated infections.

Cholera

Cholera is an acute, secretory diarrhoea caused by infection with Vibrio cholerae of the O1 or O139 serogroup. It is endemic in more than 50 countries and also causes large epidemics. Since 1817, seven cholera pandemics have spread from Asia to much of the world. The seventh pandemic began in 1961 and affects 3-5 million people each year, killing 120,000. Although mild cholera can be indistinguishable from other diarrhoeal illnesses, the presentation of severe cholera is distinct, with pronounced diarrhoeal purging. Management of patients with cholera involves aggressive fluid replacement; effective therapy can decrease mortality from more than 50% to less than 0·2%. Antibiotic treatment decreases volume and duration of diarrhoea by 50% and is recommended for patients with moderate to severe dehydration. Prevention of cholera depends on access to safe water and sanitation. Two oral cholera vaccines are available and the most effective use of these in integrated prevention programmes is being actively assessed.

Vibrio cholerae infection, novel drug targets and phage therapy

Vibrio cholerae is the causative agent of the diarrheal disease cholera. Although antibiotic therapy shortens the duration of diarrhea, excessive use has contributed to the emergence of antibiotic resistance in V. cholerae. Mobile genetic elements have been shown to be largely responsible for the shift of drug resistance genes in bacteria, including some V. cholerae strains. Quorum sensing communication systems are used for interaction among bacteria and for sensing environmental signals. Sequence analysis of the ctxB gene of toxigenic V. cholerae strains demonstrated its presence in multiple cholera toxin genotypes. Moreover, bacteriophage that lyse the bacterium have been reported to modulate epidemics by decreasing the required infectious dose of the bacterium. In this article, we will briefly discuss the disease, its clinical manifestation, antimicrobial resistance and the novel approaches to locate drug targets to treat cholera.

Single dose azithromycin versus ciprofloxacin for cholera in children: a randomized controlled trial

OBJECTIVE

To compare the clinical and bacteriological success of single dose treatment with azithromycin and ciprofloxacin in children with cholera.

DESIGN

Randomized, open labelled, clinical controlled trial.

SETTING

Tertiary care hospital.

PARTICIPANTS

180 children between 2-12 years, having watery diarrhea for < or = 24 hr and severe dehydration, who tested positive for Vibrio cholerae by hanging drop examination or culture of stool.

INTERVENTION

Azithromycin 20 mg/kg single dose (n=91) or Ciprofloxacin 20 mg/kg single dose (n=89). Dehydration was managed according to WHO guidelines.

MAIN OUTCOME MEASURES

Clinical success (resolution of diarrhea within 24 hr) and bacteriological success (cessation of excretion of Vibrio cholerae by day 3). Secondary outcome variables included duration of diarrhea, duration of excretion of Vibrio cholerae in stool, fluid requirement, and proportion of children with clinical or bacteriological relapse.

RESULTS

The rate of clinical success was 94.5% (86/91) in children treated with Azithromycin and 70.7% (63/89) in those treated with Ciprofloxacin [RR (95% CI)=1.34 (1.16-1.54); P< 0.001]. Bacteriological success was documented in 100% (91/91) children in Azithromycin group compared to 95.5% (85/89) in Ciprofloxacin group [RR (95% CI)=1.05 (1.00 -1.10); P=0.06]. Patients treated with Azithromycin had a shorter duration of diarrhea [mean(SD) 54.6 (18.6) vs 71.5 (29.6) h; mean difference (95% CI) 16.9 (9.6 -24.2); P<0.001] and lesser duration of excretion of Vibrio cholerae [mean(SD) 34.6 (16.3) vs 52.1 (29.2) h; mean difference (95% CI) 17.5 (0.2 -24.7), P<0.001] in children treated with Azithromycin vs Ciprofloxacin. The amount of intravenous fluid requirement was significantly less among subjects who received Azithromycin as compared to those who received Ciprofloxacin [mean(SD) 4704.7(2188.4) vs 3491.1(1520.5) mL; Mean difference (95% CI) 1213(645.3 - 1781.9); P<0.001]. Proportion of children with bacteriological relapse was comparable in two groups [6.7% (6/89) vs 2.2% (2/91); RR (95% CI) 0.95 (0.89 -1.01); P=0.16]. None of the children in either group had a clinical relapse.

CONCLUSION

Single dose azithromycin is superior to ciprofloxacin for treating cholera in children.

Transferable quinolone resistance in Vibrio cholerae

Ciprofloxacin was introduced for treatment of patients with cholera in Bangladesh because of resistance to other agents, but its utility has been compromised by the decreasing ciprofloxacin susceptibility of Vibrio cholerae over time. We correlated levels of susceptibility and temporal patterns with the occurrence of mutation in gyrA, which encodes a subunit of DNA gyrase, followed by mutation in parC, which encodes a subunit of DNA topoisomerase IV. We found that ciprofloxacin activity was more recently further compromised in strains containing qnrVC3, which encodes a pentapeptide repeat protein of the Qnr subfamily, members of which protect topoisomerases from quinolone action. We show that qnrVC3 confers transferable low-level quinolone resistance and is present within a member of the SXT integrating conjugative element family found commonly on the chromosomes of multidrug-resistant strains of V. cholerae and on the chromosomes of Escherichia coli transconjugants constructed in the laboratory. Thus, progressive increases in quinolone resistance in V. cholerae are linked to cumulative mutations in quinolone targets and most recently to a qnr gene on a mobile multidrug resistance element, resulting in further challenges for the antimicrobial therapy of cholera.

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.).

Évolution de la sensibilité de Vibrio cholerae 01 après utilisation prolongée d'antibiotiques en traitement et en prophylaxie au cours de l'épidémie de choléra de Douala (Cameroun) 2004

Antibiotics were extensively used, both for curative as for prophylactic purposes, to prevent an explosive spread of the 2004 cholera epidemic in Douala. It was thus necessary to control the antibiotic susceptibility of Vibrio cholerae.

OBJECTIVE

The authors had for aim to describe the epidemic, the use of antibiotics, and to follow the susceptibility of V. cholerae.

DESIGN

The 14 hospitals in the study all used the same diagnostic, treatment, and preventive protocols, as well as in community practice with home visits. All cases were clinically confirmed and reported. Samples were systematically taken at the beginning and at the end of the epidemic, and randomly during the epidemic. Each identified strain was tested by the disk method for antibiotic susceptibility.

RESULTS

Between January and September 2004, 5013 patients and 177,353 people in contact with the patients were given a single dose of doxycycline or amoxicillin for 3 days. Sixty-nine deaths were recorded (lethality 1.37%). One hundred (and) eleven strains of V. cholerae were identified in 187 samples. All of them were resistant to sulfamides and colistin, but susceptible to cyclins, betalactams, and fluoroquinolones, without any modification during the 8 months of follow-up.

CONCLUSION

Despite the risk of a massive and prolonged use of antibiotics, strictly prescribed and controlled, no resistance developed in the identified strain. Chemoprophylaxis must follow rigorous protocols and be continuously monitored.

Single-dose quinolone treatment in acute gastroenteritis

BACKGROUND

Acute diarrhea is a common disease worldwide and in Israel, a Mediterranean country. Acute bacterial gastroenteritis (ABGE) is the leading cause of severe diarrhea in Israel in summer and early autumn. Although there are some reports showing some benefit from empiric antibiotic therapy in acute gastroenteritis, most are old reports using nondefinitive diagnostic criteria and using 5-day antibiotic regimens.

AIMS

1. To examine the efficiency of antibiotic therapy in relatively severe ABGE in general. 2. To check the efficiency of the different types of quinolones in the treatment of ABGE. 3. To compare various therapy regimens.

METHODS

All patients admitted to the Barzilai Medical Center emergency room during the period June to October in 2002-2004 who were defined by protocol as having relatively severe gastroenteritis and required hospitalization in the Department of Internal Medicine were included in the study. All were randomized either to a supportive treatment only group (STG) or to the antibiotic treatment group (ATG) of ofloxacin or levofloxacin with a single dose or BID for 5 days in addition to STGs. All patients were interviewed a week later about their medical history and duration of symptomatology.

RESULTS

One hundred thirty-nine patients were found eligible for the study in the above-mentioned period. Abdominal pain resolved 1.3 days earlier in the ATG in comparison to the STG whereas vomiting and diarrhea disappeared 1.0 and 0.8 days earlier, respectively, in the ATG versus the STG. In terms of fever abatement there was no difference between the regimens and no significant difference in symptomatology disappearance between various types of quinolones used or between the single antibiotic dose regimen and the 5-day antibiotic regimen groups.

CONCLUSIONS

1. Antibiotic therapy was found to shorten duration of symptoms in patients with relatively severe gastroenteritis. 2. Single-dose therapy is as effective and certainly significantly more cost effective in comparison to the 5-day antibiotic treatment regimen.

Infectious diarrhea in developed and developing countries

Diarrhea from gastrointestinal infection remains a common problem. In industrialized countries, management is aimed at reducing morbidity and defining groups that may benefit from further investigation. Most infectious diarrhea is self-limiting and only requires supportive management. Viral agents are increasingly recognized as causative agents of epidemic and sporadic diarrhea. In developing countries, diarrhea is a major cause of mortality in children. Oral rehydration therapy, guided by a clinical assessment of the degree of dehydration, is cheap, simple, and effective and remains the mainstay of management of infant diarrhea. Controversies focus on the optimal formulation of oral rehydration solution. A vaccine against rotavirus has the potential to save millions of lives worldwide.

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.

Antimicrobial resistance in developing countries. Part I: recent trends and current status

The global problem of antimicrobial resistance is particularly pressing in developing countries, where the infectious disease burden is high and cost constraints prevent the widespread application of newer, more expensive agents. Gastrointestinal, respiratory, sexually transmitted, and nosocomial infections are leading causes of disease and death in the developing world, and management of all these conditions has been critically compromised by the appearance and rapid spread of resistance. In this first part of the review, we have summarised the present state of resistance in these infections from the available data. Even though surveillance of resistance in many developing countries is suboptimal, the general picture is one of accelerating rates of resistance spurred by antimicrobial misuse and shortfalls in infection control and public health. Reservoirs for resistance may be present in healthy human and animal populations. Considerable economic and health burdens emanate from bacterial resistance, and research is needed to accurately quantify the problem and propose and evaluate practicable solutions. In part II, to be published next month, we will review potential containment strategies that could address this burgeoning problem.

Cholera

Intestinal infection with Vibrio cholerae results in the loss of large volumes of watery stool, leading to severe and rapidly progressing dehydration and shock. Without adequate and appropriate rehydration therapy, severe cholera kills about half of affected individuals. Cholera toxin, a potent stimulator of adenylate cyclase, causes the intestine to secrete watery fluid rich in sodium, bicarbonate, and potassium, in volumes far exceeding the intestinal absorptive capacity. Cholera has spread from the Indian subcontinent where it is endemic to involve nearly the whole world seven times during the past 185 years. V cholerae serogroup O1, biotype El Tor, has moved from Asia to cause pandemic disease in Africa and South America during the past 35 years. A new serogroup, O139, appeared in south Asia in 1992, has become endemic there, and threatens to start the next pandemic. Research on case management of cholera led to the development of rehydration therapy for dehydrating diarrhoea in general, including the proper use of intravenous and oral rehydration solutions. Appropriate case management has reduced deaths from diarrhoeal disease by an estimated 3 million per year compared with 20 years ago. Vaccination was thought to have no role for cholera, but new oral vaccines are showing great promise.

Gastroenteritis and antibiotic-associated diarrhea

Acute gastroenteritis is a common cause of emergency and office visits. This article reviews causes, pathogenesis, diagnosis, prevention, and treatment. The incidence of antibiotic-associated colitis is increasing worldwide as a consequence of widespread use of broad-spectrum antibiotics for various illnesses. The pathogenic organism, Clostridium difficile, produces two enterotoxins, toxin A and toxin B, that cause colonic mucosal inflammation. C. difficile infection presents with a wide range of clinical manifestations, from asymptomatic carriers to life-threatening pseudomembranous colitis.

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.

The role of antibiotics in the treatment of infectious diarrhea

Infectious diarrhea is a significant cause of morbidity and mortality and a common complaint in clinical practice. Routine empirical use of antibiotics for infectious diarrhea should be avoided because of the self-limited nature of most cases, the cost of antibiotics, and the potential to worsen the already significant problem of antibiotic resistance of enteric pathogens. For patients with severe invasive or prolonged diarrhea or who are at high risk of complications, such as the elderly, diabetics, cirrhotics, and immunocompromised patients, empirical treatment with a quinolone antibiotic for 3 to 5 days can be considered. Antibiotic treatment can be highly effective for Shigella, ETEC, and V. cholerae infections, and metronidazole is indicated for C. difficile colitis. The impact of antibiotics for other specific pathogens is modest, and antibiotic therapy should be reserved for the same group of patients who would be considered for empirical treatment. The most significant problem in the antibiotic treatment of infectious diarrhea is the progressive increase in resistance among enteric pathogens; only the prudent use of antimicrobials in all areas of daily practice can limit or delay the impact of this serious problem.

New developments in the understanding of cholera

Recent advances in prevention and treatment of cholera have occurred in the areas of vaccine testing, modifications of oral-rehydration solutions (ORS), and antimicrobial treatment. Oral vaccines consisting of killed whole bacterial cells (WC) with and without the B-subunit of cholera toxin (BS) were shown to be effective in large trials in Bangladesh, Peru, and Vietnam. However, the trials did not resolve whether two or three doses of vaccine are required and whether BS adds significantly to the immune protection of WC. Live, attenuated bacterial vaccines that are immunogenic and have been shown protective in human volunteer studies are candidates for future field trials. Rehydration of patients is a life- saving effort. The best ORS contains rice powder in place of glucose, and solutions with reduced osmolarity (245 mOsm/L, sodium 75 mEq/L) are as effective as standard ORS. Ciprofloxacin in a single dose is effective in adults, and erythromycin or ampicillin in multiple doses is effective in children.

Small Intestinal Infections

The differential diagnosis of small intestinal infections is broad, making the identification and management of these disorders challenging. The majority of cases of acute diarrhea are self-limited and do not require diagnostic evaluation or treatment. Most patients do not require specific therapy, and treatment should focus on fluid and electrolyte replacement. In patients with severe, persistent, or chronic diarrhea, a careful medical history and routine stool testing are helpful in determining the cause. Pathogen-specific therapy should be given in patients in whom a pathogen is identified. In those without an identifiable pathogen, antidiarrheal agents are helpful in reducing the number of bowel movements and preventing further dehydration. Endoscopy may be helpful in patients with severe diarrhea and a negative stool evaluation, particularly in HIV-infected patients with chronic diarrhea. Surgery has a limited role in the management of small intestinal infections, but may be lifesaving in patients with intestinal perforation or small bowel obstruction.

Transepithelial intestinal excretion of ciprofloxacin in humans

The excretion of ciprofloxacin in the small bowel was studied in 40 patients undergoing bowel surgery. Ciprofloxacin (200 mg) was administered iv, and intestinal samples were collected over a 120-min period. In ileal loops ciprofloxacin concentrations reached a peak of 4.0 mg/L, whereas in caecal fluid samples, concentrations were < 0.16 mg/L. Ciprofloxacin administered directly into the ileal and caecal loops did not result in measurable blood levels for 2 h. The results confirm that ciprofloxacin is selectively excreted into the small bowel.

Foodborne Illnesses

Foodborne illnesses cause a substantial human and financial burden. Despite sanitary infrastructure improvements, the incidence of foodborne bacterial infections due to non-typhoidal salmonellae (NTS), Campylobacter jejuni, and enterohemorrhagic Escherichia coli (EHEC) has risen over the last two decades. Overall, viruses account for two thirds of all foodborne illness. Most foodborne illnesses are self-limited. Supportive therapy with rehydration and the correction of electrolyte abnormalities is usually sufficient. Antibiotics play a beneficial role in the treatment of patients with certain foodborne diseases, such as listeriosis and typhoid fever, and all patients with tissue invasive or bloodstream infections. Immunocompromised patients should be treated presumptively. Antibiotics are of variable efficacy for the treatment of many infections limited to the gastrointestinal tract, and recommendations differ between pathogens. Antibiotics are generally helpful for shigellosis and cholera, and possibly beneficial for campylobacteriosis. However, antibiotics are potentially harmful in uncomplicated NTS and EHEC gastroenteritis and generally should not be used. Toxin-mediated food poisoning usually does not require specific therapy. The exception is botulism, for which botulinum antitoxin is highly efficacious if used early in the course of illness. Empiric therapy for gastroenteritis is possibly beneficial, though the magnitude of benefit is modest and incurs the risk of inadvertently treating NTS or EHEC. The choice of antibiotic should be based on local resistance patterns and the results of susceptibility testing.

Oral ciprofloxacin vs. intramuscular ceftriaxone as empiric treatment of acute invasive diarrhea in children

BACKGROUND

Acute invasive diarrhea is a potentially serious condition in children. Because of the increasing resistance of enteric pathogens to commonly used oral antibiotics, intramuscular ceftriaxone has become the routine drug in the treatment of acute invasive diarrhea requiring an emergency visit in southern Israel. The inconvenience of this parenteral regimen created an increased need for oral pediatric formulations for the treatment of invasive diarrhea.

OBJECTIVES

To evaluate the efficacy and safety of a suspension formulation of ciprofloxacin in the treatment of acute invasive diarrhea in infants and children.

PATIENTS AND METHODS

From July 1996 through December 1997, 201 evaluable children ages 6 months to 10 years (35% <1 year; 70% <3 years) presenting with acute invasive diarrhea at the Pediatric Emergency Room were randomized to receive either ciprofloxacin suspension (10 mg/kg twice a day + im placebo; n = 95) or im ceftriaxone (50 mg/kg/day + placebo suspension; n = 106) for 3 days in a double blind manner. Stool cultures for Shigella, Salmonella, Campylobacter spp. and diarrheagenic Escherichia coli were obtained on Days 1, 3, 4 to 5 and 21 +/- 5. Clinical response and safety were assessed on Days 1, 2, 3, 4 to 5 and 21 +/- 5.

RESULTS

We isolated 127 pathogens from 121 (60%) patients: 73 (57%) Shigella; 23 (18%) Salmonella; 18 (14%) E. coli; and 13 (10%) Campylobacter. Overall bacteriologic eradication on Day 4 to 5 was 99% for Shigella, 77% for Salmonella and 77% for Campylobacter, with no difference between the 2 groups. Clinical cure or improvement was observed in 100 and 99% of the ciprofloxacin and ceftriaxone groups, respectively. Serum ciprofloxacin values determined on Day 3 of the treatment were higher in the majority of patients than were the MIC50 and MIC90 values for the Shigella and Salmonella spp. isolated. Possible drug-related adverse events occurred in 13 patients [ciprofloxacin, 8 (8%); ceftriaxone, 5 (4.7%)] and were mild and transient. Joint examination was normal during and after completion of therapy in all patients.

CONCLUSION

Oral ciprofloxacin was as safe and effective as intramuscular ceftriaxone for the empiric treatment of acute invasive diarrhea in ambulatory pediatric patients requiring an emergency room visit.

Treatment of bacillary dysentery in Vietnamese children: two doses of ofloxacin versus 5-days nalidixic acid

Nalidixic acid (NA: 55 mg/kg daily for 5 days) is the recommended treatment for uncomplicated bacillary dysentery in areas where multidrug-resistant Shigella are prevalent. An open randomized comparison of this NA regimen with 2 doses of ofloxacin (total 15 mg/kg) was conducted in 1995/96 in 135 Vietnamese children with fever and bloody diarrhoea. Sixty-six children with a bacterial pathogen isolated were eligible for analysis. Of the 63 Shigella isolates, 39 (62%) were resistant to multiple antibiotics. Resolution times for fever and diarrhoea were similar in the 2 groups, but excretion time of stool pathogen was significantly longer in the NA recipients [median (range) days 1 (1-9) vs 1 (1-2), P = 0.001]. There were 9 (25%) treatment failures in the NA regimen and 3 (10%) in the ofloxacin group; P = 0.1. Two patients had NA-resistant Shigella flexneri. One of these isolates was selected during NA treatment. From a clinical and public health standpoint a 2-dose regimen of ofloxacin is preferable to nalidixic acid in the treatment of bacillary dysentery.

Randomised comparison of ciprofloxacin suspension and pivmecillinam for childhood shigellosis

BACKGROUND

Infections caused by multiply resistant Shigella species are a major cause of childhood morbidity and mortality in Third World countries. The fluoroquinolone agent ciprofloxacin is active in vitro against these strains of bacteria, but has not been routinely used to treat acute childhood infections because of concern that quinolones may cause arthropathy in children. We undertook a randomised double-blind study to test the effects of ciprofloxacin treatment in children with shigella dysentery.

METHODS

We compared the efficacy and toxic effects of ciprofloxacin suspension (10 mg/kg every 12 h for 5 days, maximum individual dose 500 mg) with those of pivmecillinam tablets (15-20 mg/kg every 8 h for 5 days, maximum individual dose 300 mg). We enrolled 143 children aged 2-15 years with dysentery of 72 h or less duration. Patients stayed in hospital for 6 days, and were followed up 7, 30, and 180 days after hospital discharge. Joint symptoms and function were assessed daily for 6 days. Clinical success was defined as the absence of frank dysentery on day 3, and on day 5 no bloody-mucoid stools, one or no watery stool, six or fewer total stools, and no fever. If no shigella were isolated from faecal samples on day 3 or thereafter, treatment was judged bacteriologically successful.

FINDINGS

13 patients were excluded since they did not meet eligibility criteria; 10 withdrew before day 5. Thus 120 patients (60 in each group) completed the study. Treatment was clinically successful in 48 (80%) of 60 patients who received ciprofloxacin and in 39 (65%) of 60 patients who received pivmecillinam (p=0.10). Treatment was bacteriologically successful in all of the patients receiving ciprofloxacin, and in 54 (90%) of the patients receiving pivmecillinam (p=0.03). Joint pain after treatment began in 13 (18%) of 71 patients who received ciprofloxacin and 16 (22%) of 72 patients who received pivmecillinam (p>0.2), and no patient had signs of arthritis.

INTERPRETATION

In our trial, ciprofloxacin suspension and pivmecillinam had the same clinical efficacy. Ciprofloxacin had greater bacteriological efficacy and was not associated with the development of arthropathy. We conclude that ciprofloxacin is an effective and safe drug for use in multiply resistant childhood shigellosis.

Effect of cholera toxin on intestinal elimination of ciprofloxacin in rabbits

The transepithelial intestinal elimination of ciprofloxacin (CPX) was studied in cholera toxin (CT)-challenged and control intestinal loops in the rabbit. CPX concentrations were similar in CT-challenged and control jejunal and ileal loops, while cecal elimination was negligible. The quantities of eliminated CPX per square centimeter of bowel wall were significantly higher in the small intestine CT-challenged loops. The mechanism of elimination of CPX in the small intestine is therefore mainly passive diffusion.

A week in the life of a travel clinic

International travel has increased enormously in recent years. With the greater movement of people have come increased encounters with a wide variety of diseases: malaria, dengue, cholera, typhoid fever, Ebola virus, and many more. The need for greater scope, consistency, and knowledgeability in pretravel health care to meet these challenges has been met by the emergence of the discipline of travel medicine. Travelers are well advised to become informed of the risks they face and to take steps to minimize those risks. After reviewing a traveler's medical history and a detailed itinerary, a travel medicine practitioner can offer expert advice on behavioral modifications, immunizations, and chemoprophylaxis regimens which will increase the traveler's margin of safety. The issues most frequently addressed in a travel clinic include treatment of traveler's diarrhea, malaria chemoprophylaxis, and immunizations, for hepatitis A, typhoid fever, tetanus/diphtheria, influenza, pneumococcus, hepatitis B, polio, meningococcus, measles, mumps, rubella, varicella, and rabies. Pretravel consultation must consider the age and underlying health problems of the traveler, the nature of the trip (wilderness, jungle, rural, urban, resort, or cruise), the duration of travel, and the latest available information on the site in terms of disease outbreaks, terrorism, and natural calamities.