Côte d’Ivoire has the largest cashew tree cultivation area in the world, but the cashew apple produced is still underutilized despite its potential for industrial use. The present study aimed to isolate and identify acetic acid bacterial strains and assess their potential use for cashew apple-based vinegar production. Vinegar mother from fermented juice was used to isolate acetic acid bacteria on a standard glucose-based medium. Physiological and biochemical tests followed by 16S rRNA gene analysis and phylogeny were used for isolate characterization. Moreover, their acetic acid production capacity was assessed. As results, five strains of the Acetobacter genus were isolated. Phenotypic and phylogenetic analysis revealed that four of them, namely OYA2, OYA6, OYA9, and OYA10, belong to the A. tropicalis/A. senegalensis species complex with 99.7% or 100% similarity. The fifth strain, OYA7, being similar (99.7%) to A. syzygii. All the isolates were resistant to alcohol 15% (v/v) and grew well between pH 5.0 and 6.5. Their optimal growth temperatures varied between 27 °C and 37 °C, and only isolate OYA6 grew at a temperature of up to 40 °C. They produced vinegar with a yield (Y_p/s, g/g) varying from 0.82 to 0.92, and acetic acid contents (g/L) of 80.67, 70.26, 70.11, 68.70 and 67.22 were obtained with OYA6, OYA7, OYA2, OYA10, and OYA9, respectively. Thus, the isolate OYA6 appeared as the best candidate for vinegar production, owing to its superior yield and thermotolerance abilities that need to be further explored for industry use.

The emergence and dissemination of extended-spectrum beta-lactamase (ESBL)-producing bacteria pose a major public health threat, necessitating a One Health approach to addressing this threat. Thus, the diversity, ESBL production, and potential public health implications of Gram-negative bacteria recovered from man-made lakes and surrounding lettuce in Yamoussoukro, Côte d’Ivoire were assessed in this study. Also, the lakes’ physicochemical parameters were assessed and correlated with bacteria community using Pearson correlation. A total of 68 Gram-negative bacterial isolates were recovered from the samples and identified via 16S rDNA gene sequencing. Phylogenetic analysis suggested multiple genus-/species-level variations within the isolates. Escherichia coli was the most prevalent in lake water (39.5%), while Acinetobacter was the dominant genus in lettuce (30%). E. coli isolates showed high resistance to ampicillin (90.9%), cefepime (72.7%), cefotaxime (68.2%), and aztreonam (63.6%). Moreover, ESBL production was confirmed in E. coli isolates (22.05%), predominantly mediated by the bla_CTX-M gene. Multidrug-resistant phenotypes were widespread, yielding similar multiple antibiotic resistance index (MARI) values in water (0.27–0.63) and lettuce (0.27–0.81). These data indicate high environmental contamination, which unfortunately is not being taken into account by lettuce producers according to an interview. Statistical analyses showed a significant relationship between bacterial diversity and lakes’ physicochemical parameters, including dissolved oxygen, pH, and turbidity. The basic education level of farmers, the prevalence of ESBL-producing E. coli, and the high prevalence of MDR Gram-negative bacteria in both environmental and crop sources in Yamoussoukro underscore the need for both integrated surveillance and management strategies to mitigate potential microbial public health risks within a One Health framework.

Côte d’Ivoire has the main cashew tree culture area worldwide, but the cashew apple produced is still underutilized although its potential for industry. In the present study, the aim was to isolate and identify acetic acid bacterial strains, and to assess their potential use for cashew apple-based vinegar production. Vinegar mother from fermented juice was used to isolate acetic acid bacteria on a standard glucose-based medium. Physiological and biochemical tests followed by 16S rRNA gene analysis and phylogeny were used for isolate characterization. Moreover, their acetic acid production capacity was assessed. As results, five (05) strains of the Acetobacter genus were isolated. Phenotypic and phylogenetic analysis revealed that four of them, namely OYA2, OYA6, OYA9, and OYA10, belong to A. tropicalis / A. senegalensis species complex with 99,7% or 100% similarity. The last strain, OYA7, match to A. syzygii (99,7%). All the isolates were resistant to 15° alcohol (v/v) and grew well between pH 5.0 and 6.5. Their optimal growth temperatures varied between 27°C and 37°C, and only isolate OYA6 grows up to 40°C. They produced vinegar with yield (Yp/s , g/g) varying from 0.82 to 0.92, and acetic acid content (g/L) of 80.67 ± 2.1, 70.26 ± 0.9, 70.11 ± 1.7, 68.70 ± 1.5 and 67.22 ± 0.40 were obtained with OYA6, OYA7, OYA2, OYA10, and OYA9, respectively. Thus, the isolate OYA6 appeared as the best candidate for vinegar production, owing to its superior yield and thermotolerance ability that need to be further explored for industry use purpose.