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

D, lydie N. A, Allico J. D, Mady N, Mireille D. Resistance Profile of Vibrio spp. Strains Collected from Lagoon Bays and Wastewater in the City of Abidjan, Côte d'Ivoire, from January to June 2017

Background:

Lagoons and wastewater constitute aquatics environments which receive or accounts for most domestic discharges. These waters constitute an important ecosystem for the proliferation of microorganisms. The microorganisms that harbor these waters can provide information on the persistence of certain diseases in the human population, including gastrointestinal infections such as Cholera. The genus Vibrio contains pathogenic aquatic bacteria found in lagoon bays and wastewater.

Objective:

The main objectives of this work were to confirm the presence of Vibrio spp. in lagoon bays and sewage of the city of Abidjan over the entire interepidemic period, and to evaluate their sensitivity to commonly used antibiotics.

Methods:

The isolation and identification of the microorganisms were carried out using classical bacteriological techniques (biochemical test, API 20E gallery). When necessary, serotyping was carried out using agglutination tests on slides. Antibiotic susceptibility testing was carried out using the Kirby-Bauer disk diffusion (KBDD) method.

Results:

This study identified 12 bacterial strains, 9/12 (75%) of which were Vibrio sp. strains. Two Vibrio species, namely Vibrio parahaemolyticus 2/9 (22%) and 7/9 Vibrio cholerae (78%) were identified.

V. cholerae was isolated from both sewage and lagoon waters with dominance of serotype O1. The V. cholerae O1 and non-O1 strains showed a high level of resistance to sulfonamides, quinolones, fluoroquinolones, and moderate sensitivity to penicillins and tetracyclines. Resistant V. parahaemolyticus strains were also identified.

Conclusion:

The increased resistance of these bacteria could pose potential problems in the treatment of epidemics and other communicable diseases. The emergence of these multi-drug resistant strains of the genus Vibrio should prompt the Ivorian health authorities to maintain an epidemiological surveillance network for waterborne diseases throughout the country and to continue bacteriological sampling to monitor Vibrio's sensitivity to antibiotics.

Multi-drug resistant toxigenic Vibrio cholerae O1 is persistent in water sources in New Bell-Douala, Cameroon

BACKGROUND

Cholera has been endemic in Douala, since 1971 when it was first recorded in Cameroon. Outbreaks have often started in slum areas of the city including New Bell. Despite the devastating nature of outbreaks, always resulting in high mortality and morbidity, a paucity of information exists on the reservoirs of the causative agent, V. cholerae, and factors maintaining its persistence. This has complicated disease prevention, resulting in frequent outbreaks of cholera. We investigated water sources in New Bell for contamination with V. cholerae O1 with pathogenic potential, to highlight their role in disease transmission. Antibiotic susceptibility pattern of isolates and the environmental factors maintaining its persistence were investigated.

METHOD

Water samples from various sources (taps, dug wells, streams) were analyzed for contamination with V. cholerae O1 using standard methods. Antibiotic susceptibility was determined by disc diffusion method. Pathogenic potential of isolates was determined by analyzing for genes for cholera toxin (ctx), toxin co-regulated pilus (tcpA), and zonula occludens toxin (zot) by PCR. Physico-chemical characteristics of water (pH, temperature and salinity) were investigated using standard methods. The Spearman's Rank correlation was used to analyze the relationship between physico-chemical factors and the occurrence of V. cholerae O1. Differences were considered significant at P≤0.05.

RESULTS

Twenty-five V. cholerae O1 strains were isolated from stream and well samples in both dry and rainy seasons. Twenty-three (92%) isolates were multidrug resistant. All isolates had genes for at least one virulence factor. Cholera toxin gene was detected in 7 isolates. Of the 15 isolates positive for tcpA gene, two had Classical type tcpA while 13 had tcpA El Tor. All tcpA Classical positive isolates were positive for ctx gene. Isolates were grouped into nine genotypes based on the genes analyzed. pH and salinity significantly correlated with isolation of V. cholerae O1.

CONCLUSION

Multidrug resistant Vibrio cholerae O1 with pathogenic potential is present in some wells and streams in study area. pH and salinity are among the factors maintaining the persistence of the organism. Findings indicate an urgent need for potable water supply in study area and in addition, regular disinfection of water from contaminated sources to prevent outbreak of cholera.

A cluster of acute diarrhea suspected to be cholera in French travelers in Haiti, December 2010

A cluster of 21 cases of watery diarrhea suspected to be cholera that involved French military policemen and young volunteers occurring in the context of the Haiti cholera outbreak is described. The attack rate (AR) was higher among young volunteers (71.4%) than among policemen (15.3%) (p < 0.0001). There was a significant association between raw vegetables consumption and watery diarrhea in the young volunteer group. If we consider the raw vegetables consumers only, AR was lower among doxycycline-exposed subjects (relative risk: 0.2; 95% confidence interval: 0.1-0.4). The main aspect that is of scientific interest is the potential prophylactic effect of doxycycline used for malaria prophylaxis on the watery diarrhea AR.

Chemoprophylaxis in contacts of patients with cholera: systematic review and meta-analysis

INTRODUCTION

There is a pressing need for effective measures to prevent the spread of cholera. Our systematic review assesses the effects of chemoprophylaxis in preventing cholera among exposed contacts.

METHODS AND FINDINGS

We considered published and unpublished reports of studies up to July 2011. For this we searched: PubMed (1966 to July, 2011), Embase (1980 to July 2011), Cochrane Central Register of Controlled Trials (6; 2011), LILACS (1982 to July, 2011), the International Clinical Trials Registry Platform (July 2011) and references of identified publications. We included controlled clinical trials (randomized and non-randomized) in which chemoprophylaxis was used to prevent cholera among patient contacts. The main outcome measures were hospitalization and laboratory diagnosis of cholera in contacts for cholera patients. We assessed the risk of bias. We identified 2638 references and these included 2 randomized trials and 5 controlled trials that added up to a total of 4,154 participants. The risk of bias scored high for most trials. The combined results from two trials found that chemoprophylaxis reduced hospitalization of contacts during the follow-up period by 8-12 days (2826 participants; RR 0.54 95% CI 0.40-0.74;I² 0%). A meta-analysis of five trials found a significant reduction in disease among contacts with at least one positive sample who received chemoprophylaxis during the overall follow-up (range 4-15 days) (1,414 participants; RR 0.35 95% CI 0.18-0.66;I² 74%). A significant reduction in the number of positive samples was also found with chemoprophylaxis (3 CCT; 6,918 samples; RR 0.39 95% CI 0.29-0.51;I² 0%).

CONCLUSION

Our findings suggest that chemoprophylaxis has a protective effect among household contacts of people with cholera but the results are based on studies with a high risk of bias. Hence, there is a need for adequate reliable research that allows balancing benefits and harms by evaluating the effects of chemoprophylaxis.