Prevalence of Resistant Enterobacterales, in Particular ESBL-Producing Escherichia coli in Hospital Wastewater Discharged into the Environment: Study of the Abidjan District, Côte d’Ivoire

Aims: Hospital effluent constitutes a reservoir for antibiotic-resistant bacteria. In particular, Gram-negative bacteria carrying several antibiotic resistance genes. This study was to evaluate the prevalence of antibiotic-resistant Enterobacterales and ESBL Escherichia coli in hospital effluents.

Methodology: In total, 112 wastewater samples from 4 hospital sites were collected and examined during 2020 at the Pasteur Institute of Côte d’ivoire. Enumeration of total Enterobacterales was carried out on McConkey agar. McConkey agar was supplemented with 4 mg/l ceftazidime to detect resistant Enterobacterales. Antibiotic-resistant Escherichia coli were identified using MALDI-TOF MS. The production of ESBL was investigated by synergy tests on Mueller-Hinton agar.

Results: The results indicate a prevalence of resistant Enterobacterales varied between 4.6% and 2.6% with an average of 3.9%. A proportion of 69.2% of resistant Enterobacterales were strains of Escherichia coli. ESBL Escherichia coli represented a rate of 32.7% among resistant Enterobacterales. A rate of 47.3% of resistant Escherichia coli strains produced an ESBL. It appears from this study that the phenomenon of multi-resistance is undoubtedly present in bacteria isolated from hospital effluents, because the Enterobacterales isolated from these waters are mainly strains of ESBL-producing Escherichia coli.

Conclusion: Resistant Enterobacterales and particularly ESBL-producing Escherichia coli present in hospital effluents released without treatment into the environment are likely to cause public health problems. These bacteria should be considered environmental pollutants.