Optimization of Technical Parameters for Detecting Mycobacteria in Hospital Wastewater in Tropical Urban Areas: The Case of the City of Abidjan (Côte d’Ivoire)

The loads of organic matter, microorganisms, detergents and antibiotics in liquid hospital effluents make them complex environments, raising numerous health and ecological questions. Investigations of mycobacteria in water lack adequate techniques. This study is the first part of a pilot project aimed at developing an optimized protocol for the isolation of mycobacteria from hospital effluents, as a prelude to more in-depth investigation in this matrix. The aim was to compare the performance of two decontamination methods, three culture media and two incubation temperatures generally proposed in the literature, in order to identify the most effective methods in each case, as well as possible areas for improvement in the isolation of these germs from this environmental matrix. The results show that liquid hospital effluent can be decontaminated using both the NaOH method (4%; for 30 min.) and the CPC method (0.05%; for 30 min.), with the same mycobacteria recovery efficiency. Despite the low concentration, decontamination with CPC killed more mycobacteria and sufficiently eliminated contaminating germs. In contrast, decontamination with NaOH was less harmful to mycobacteria, but did not remove many contaminating germs. On the other hand, LJG medium performed better than LJGF medium and LJGP medium for the growth of mycobacteria in hospital waters. Finally, there was no difference in performance between the two incubation temperatures of 30℃ and 37℃. The results of this study show that further evaluation of existing protocols is required in order to optimize methods for the pre-treatment of hospital effluent for the isolation of mycobacteria.