Resistance Profile of Escherichia coli Strains Isolated from the Diarrhoeal Faeces of Children Aged 0 to 5 Years in N'Djamena and Sarh (Chad)

Escherichia coli diarrhoea remains a public health problem in Chad. It is a common pathology in developing countries, particularly where hygiene levels are low. In children aged 0-5 years, it remains the leading cause of morbidity and mortality from digestive pathologies. Its management raises questions about its resistance to the drugs used to treat it. The aim of this study is therefore to determine the prevalence of Escherichia coli strains and their resistance profiles to the antibiotics commonly used in Chad. Stools from children aged 0-5 years were collected in sterile jars and sent to the Centre Hospitalier Universitaire de la Mère et de l'Enfant for microbiological analysis. The stools were cultured on Eosin Methylene Blue (EMB) agar and incubated in a bacteriological oven for 18 to 24 hours at 37°C. Colonies from this culture, with a metallic sheen, were subcultured onto Muller Hinton agar for purification and antigenic studies. Gram staining and oxidase tests were performed on the different strains. Biochemical identification of the isolates was carried out using the API20E Gallery in accordance with Bio Mérieux recommendations. Antibiotic susceptibility testing of the various strains was carried out using the Kyrbi-Bauer technique and in accordance with the recommendations of the Antibiogram Committee of the French Microbiology Society (CA-SFM). Of the 296 stools treated, 36 strains of E. coli were isolated, giving a prevalence of 12.2%. The strains were multi-resistant to the various families of antibiotics used. High resistance to β-lactam antibiotics was observed, with 86.11% for cefotaxime, 83.33% for ceftriaxone, 72.22% for cefepime and 63.60% for ceftaxidime. All strains were resistant to aminopenicillins, with frequencies of 86.11% for amoxicillin-clavunalic acid and 83.33% for amoxicillin. However, imipenem was effective against all the strains studied. Aminoglycosides showed a resistance rate of 77.78% for gentamicin and 80.56% for tobramicin. Amicakacin was the most effective molecule, with a resistance rate of 44.44%. Quinolones and fluorquinolones showed resistance of 69.44% for nalixidic acid, 80.56% for ciprofloxacin and 72.22% for ofloxacin. Cotrimoxazole was the only sulphonamide used, with 88.89% resistance. Escherichia coli are still common in children aged 0-5 years. The strains are multi-resistant to the antimicrobials used. The circulation of such strains requires further study to gain a better understanding of their origin and mode of dissemination.