Antimicrobial susceptibility of autochthonous aquatic Vibrio cholerae in Haiti

We investigated the antimicrobial susceptibility of 50 environmental isolates of Vibrio cholerae non-O1/non-O139 collected in surface waters in Haiti in July 2012, during an active cholera outbreak. A panel of 16 antibiotics was tested on the isolates using the disk diffusion method and PCR detection of seven resistance-associated genes (strA/B, sul1/2, ermA/B and mefA). All isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, ciprofloxacin, norfloxacin, amikacin and gentamicin. Nearly a quarter (22.0%) of the isolates were susceptible to all 16 antimicrobials tested and only 8.0% of the isolates (n=4) were multidrug-resistant. The highest proportions of resistant isolates were observed for sulfonamide (70.0%), amoxicillin (12.0%) and trimethoprim-sulfamethoxazole (10.0%). One strain was resistant to erythromycin and one to doxycycline, two antibiotics used to treat cholera in Haiti. Among the 50 isolates, 78% possessed at least two resistance-associated genes, and the genes sul1, ermA and strB were detected in all four multidrug-resistant isolates. Our results clearly indicate that the autochthonous population of V. cholerae non-O1/non-O139 found in surface waters in Haiti shows antimicrobial patterns different from that of the outbreak strain. The presence in the Haitian aquatic environment of V. cholerae non-O1/non-O139 with reduced susceptibility or resistance to antibiotics used in human medicine may constitute a mild public health threat

Antimicrobial Susceptibility among Urban Wastewater and Wild Shellfish Isolates of Non-O1/Non-O139 Vibrio cholerae from La Rance Estuary (Brittany, France)

The early 2000s marked the end of the Golden age of the antibiotics and the beginning of the awareness on the potential threat to human health due to the dissemination of antimicrobial resistance. As a base-line study, we investigated the antimicrobial susceptibility of 99 strains of non-O1/non-O139 Vibrio cholerae isolated from wastewater and shellfish in 2000/2001 within La Rance estuary (Brittany, France). All isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, chloramphenicol, nalidixic acid, ciprofloxacin, norfloxacin, amikacin, gentamicin, tetracycline, doxycycline, trimethoprim-sulfamethoxazole, and erythromycin. The only resistances were to streptomycin, sulfonamides and ampicillin: 54.6% of the isolates had acquired resistance to at least one antimicrobial agent among them and only six isolates from cockles were multidrug resistant. On the basis of the distribution of a limited selection of resistance associated genes, our study shows that V. cholerae can constitute an environmental reservoir for these genes. However, none of our isolates harbored integron. This result casts doubt on the capacity of non-O1/non-O139 V. cholerae to acquire resistance-associated genes in such context, and on its potential role of indicator of the dissemination of antimicrobial resistance in the aquatic environment

Antimicrobial Susceptibility among Urban Wastewater and Wild Shellfish Isolates of Non-O1/Non-O139 Vibrio Cholerae from La Rance Estuary (Brittany, France)

International audienceThe early 2000s marked the end of the Golden age of the antibiotics and the beginning of the awareness on the potential threat to human health due to the dissemination of antimicrobial resistance. As a base-line study, we investigated the antimicrobial susceptibility of 99 strains of non-O1/non-O139 Vibrio cholerae isolated fromwastewater and shellfish in 2000/2001 within La Rance estuary (Brittany, France). All isolates were susceptible to amoxicillin-clavulanic acid, cefotaxime, imipenem, chloramphenicol, nalidixic acid, ciprofloxacin, norfloxacin, amikacin, gentamicin, tetracycline, doxycycline, trimethoprim-sulfamethoxazole, and erythromycin. The only resistances were to streptomycin, sulfonamides and ampicillin: 54.6% of the isolates had acquired resistance to at least one antimicrobial agent among them and only six isolates from cockles were multidrug resistant. On the basis of the distribution of a limited selection of resistance associated genes, our study shows that V. cholerae can constitute an environmental reservoir for these genes. However, none of our isolates harbored integron. This result casts doubt on the capacity of non-O1/non-O139 V. cholerae to acquire resistance-associated genes in such context, and on its potential role of indicator of the dissemination of antimicrobial resistance in the aquatic environment

Intégrons provenant d'isolats d'Aeromonas prélevés sur des poissons : Un indicateur global de la résistance aux antimicrobiens et de la pollution anthropique

International audienceAntimicrobial resistance (AMR) is now considered to be a major public health issue. AMR needs to be tackled following a One Health approach. With regard to antibiotic use and anthropic activity, fish farming is an appealing model to study the effects of antibiotic exposure on the rise of AMR. Aeromonas is at the interface of all the One Health components and represents an ideal test case in the One Health approach. Integrons which are genetic elements observed in Gram-negative bacteria are considered as a good proxy to monitor AMR dissemination. Here, we propose that Aeromonas from fish and integrons, could provide a consistent marker, when combined, of the level of acquired AMR in the environment.To investigate the link between integrons among Aeromonas from fish and anthropic pollution, we determined integron prevalence in a unique collection of Aeromonas isolates recovered from wild fish (WF), farmed fish (FF) and diseased fish (DF). The search for integrons from Aeromonas was performed using qPCR. Minimum Inhibitory Concentrations (MICs) were determined for the antibiotics commonly used in aquaculture and compared between integron-positive and integron-negative Aeromonas.Out of 379 non-redundant isolates, 69 Aeromonas harboured integrons. The proportion of integron-positive Aeromonas was significantly higher in the DF collection (34/70, 48.6%) compared to the FF collection (35/231, 15.2%) (p ≤ 0.001) whilst no integrons were detected among the 231 Aeromonas isolates of the WF collection. A significant link between integrons and MICs was observed for tetracycline, trimethoprim-sulfamethoxazole and flumequine. Following a One Health approach, this study proposes the combination of two well-known biomarkers of AMR, integrons and Aeromonas collected from fish, as a novel potential indicator of AMR and anthropic pollution in the environment

Influence of incubation time on antimicrobial susceptibility testing of pathogenic Vibrio anguillarum and Vibrio vulnificus isolated from fish

A multi-laboratory study was performed to investigate the most suitable incubation time for susceptibility tests of fish pathogens Vibrio anguillarum and Vibrio vulnificus performed at 28 degrees C. An isolate set consisting of 30 V. anguillarum and 26 V. vulnificus was used by four participating laboratories in Denmark, France, Sweden, and the Netherlands. Inhibition zone diameters were determined by agar disc diffusion for eight agents and Minimum Inhibitory Concentration (MIC) values were determined for seven agents using the standard CLSI testing protocols for non-fastidious organisms that specify 24-28 h incubation. In this work an additional set of readings was made after 48 h incubation. In total, 1120 paired zone sizes and 399 paired MIC observations were made at the two incubation times. Examination of the data demonstrated that incubation time had a small but statistically significant effect on the numerical values of susceptibility measures. However, the effects of incubation time on the precision of the data sets and the categorisation of isolates based on the application of epidemiological cutoff values were slight and statistically non significant. These analyses suggest that the susceptibility of these Vibrio species could be established using protocols that specify either 24-28 h or 44-48 h incubation.This study does not provide evidence that prolonged incubation to 48 h improves the quality of data generated by the tests. Therefore, it is recommended that the existing standard CLSI protocols with 24-28 h at 28 degrees C should be adopted for susceptibility testing of V. anguillarum and V. vulnificus.This study was performed in the frame of CoVetLab partner Insitutes https://www.covetlab.org/c5/peer-reviewe

Influence of incubation time on antimicrobial susceptibility testing of pathogenic Vibrio anguillarum and Vibrio vulnificus isolated from fish

A multi-laboratory study was performed to investigate the most suitable incubation time for susceptibility tests of fish pathogens Vibrio anguillarum and Vibrio vulnificus performed at 28 degrees C. An isolate set consisting of 30 V. anguillarum and 26 V. vulnificus was used by four participating laboratories in Denmark, France, Sweden, and the Netherlands. Inhibition zone diameters were determined by agar disc diffusion for eight agents and Minimum Inhibitory Concentration (MIC) values were determined for seven agents using the standard CLSI testing protocols for non-fastidious organisms that specify 24-28 h incubation. In this work an additional set of readings was made after 48 h incubation. In total, 1120 paired zone sizes and 399 paired MIC observations were made at the two incubation times. Examination of the data demonstrated that incubation time had a small but statistically significant effect on the numerical values of susceptibility measures. However, the effects of incubation time on the precision of the data sets and the categorisation of isolates based on the application of epidemiological cutoff values were slight and statistically non significant. These analyses suggest that the susceptibility of these Vibrio species could be established using protocols that specify either 24-28 h or 44-48 h incubation.This study does not provide evidence that prolonged incubation to 48 h improves the quality of data generated by the tests. Therefore, it is recommended that the existing standard CLSI protocols with 24-28 h at 28 degrees C should be adopted for susceptibility testing of V. anguillarum and V. vulnificus.This study was performed in the frame of CoVetLab partner Insitutes https://www.covetlab.org/c5