Multisectoriel
Approche One Health multi-interface
Resistance aux antimicrobiens multi-secteurs
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 blaCTX-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.
📅 2025
📰 Microorganisms
DOI
Santé Végétale
Agriculture durable et One Health
Fusariose
Bacillus velezensis strain G2T39 is an endophytic bacterium previously isolated from Crotalaria retusa L., with evidenced biocontrol activity against Fusarium oxysporum f. sp. Cubense and Fusarium graminearum. In this study, it was shown that this strain also exhibited biocontrol activity against Colletotrichum gloeosporioides and Fusarium oxysporum f. sp. Vasinfectum, two important crop pathogens in tropical zones. Comprehensive phylogenetic and genomic analyses were performed to further characterize this strain. The genome of B. velezensis G2T39 consists of a single circular chromosome of 4,040,830 base pairs, with an average guanine-cytosine (GC) content of 46.35%. Both whole-genome-based phylogeny and average nucleotide identity (ANI) confirmed its identity as B. velezensis, being closely related to biocontrol and plant growth promotion Gram-positive model strains such as B. velezensis FZB42. Whole-genome annotation revealed 216 carbohydrate-active enzymes and 14 gene clusters responsible for secondary metabolite production, including surfactin, macrolactin, bacillaene, fengycin, bacillibactin, bacilysin, and difficidin. Genes involved in plant defense mechanisms were also identified. Additionally, G2T39 genome harbors multiple plant growth-promoting traits, such as genes associated with nitrogen metabolism (nifU, nifS, nifB, fixB, glnK) and a putative phosphate metabolism system (phyC, pst glpQA, ugpB, ugpC). Additional genes linked to biofilm formation, zinc solubilization, stress tolerance, siderophore production and regulation, nitrate reduction, riboflavin and nicotinamide synthesis, lactate metabolism, and homeostasis of potassium and magnesium were also identified. These findings highlight the genetic basis underlying the biocontrol capacity and plant growth-promoting properties of B. velezensis G2T39 and support its potential application as a sustainable bioinoculant in agriculture.
📅 2026
📰 Microorganisms
DOI
Santé Végétale
64 endophytic bacteria were isolated from roots, stems, and leaves of Crotalaria retusa L., a medicinal plant well-known for its antimicrobial properties in Côte d'Ivoire. Taxonomic characterization revealed that these bacteria were mainly dominated by the genera Pseudomonas, Rhizobium, Bacillus, and Inquilinus. The antagonistic activities of the endophytic bacteria against two phytopathogenic fungi affiliated with the genus Fusarium were tested using in vitro coculture. Isolates belonging to the genus Inquilinus showed the highest inhibitory activities against Fusarium oxysporum f. sp. cubense, ranging from 40% to 57%, while the highest inhibitory activities against Fusarium graminearum were obtained with Bacillus isolates (∼66%). Finally, a metabolomic study of the leaves, stems, and seeds of the plant and of the endophytes presenting antifungal activity was carried out using LC-MS/MS analysis of the methanolic extracts of all active endophytic isolates. The identified metabolites of interest from the endophytes were mainly peptides, lipids, and steroids. Two pyrrolizidine alkaloids, monocrotaline and senecionine, were detected in the plant organs but not in the endophytic bacterial extracts. These results highlighted the potential of C. retusa L. plant and its endophytic microbiome as a source of bioactive molecules of interest and biocontrol agents against phytopathogenic Fusarium spp.
📅 2025
📰 FEMS Microbiology Letters
DOI
