Gram-negative bacilli isolated from humans, animals, foodstuffs, and the environment: molecular proof of spread

Wedjène Mansour-Ben Romdhane

Faculté de médecine IBN EL Jazzar de Sousse, Sousse, Tunisie

In the One Health context, the antibiotic resistance spread should be analyzed from several perspectives using valid tracers to gain a full understanding of the spread dynamics and develop targeted action plans. In this context, research conducted by our team has described the antibiotic resistance molecular mechanisms in Gram-negative bacilli isolated from humans, animals, foodstuffs, and the environment. Bacteria described as critical by the WHO were studied, and their resistance mechanisms were evaluated. The predominance of enterobacteria and non-fermenting Gram-negative bacilli among the isolates was high; Priority was given to the genes conferring resistance to cephalosporins, carbapenems and colistin. The CTX-M group BLSE is particularly well represented in the isolates from different contexts. Carbapenemases were found in more than one context, encoded by the same plasmids, and in closely related bacteria. We observed resistance to the last-resort antibiotic, colistin, and both plasmid and chromosomal resistances were described. The molecular proof of the spread is clear, and plans of action to fight antibiotic resistance must be based on the monitoring of reliable molecular tracers to enhance the effectiveness of interventions.