Olive Vivien Noah Ewoti*1, Luciane Marlyse Moungang1, Raisa Morelle Djeala1, Antoine Tamsa Arfao1, Raoul Polycarpe Tuekam Kayo2, Mireille Ebiane Nougang3, Claire Stephane Metsopkeng1, Yves Yogne Poutoum1 and Moïse Nola1.
*Corresponding author: noahewoti@yahoo.fr
1 Laboratory of Hydobiology and Environment, Department of Animal Biology and Physiology, Faculty of Science, University of Yaounde 1, PO Box 812.
2 Laboratory of microbiology, Department of microbiology, Faculty of Science, University of Bamenda.
3 Laboratory of Zoology, Faculty of Science, University of Maroua, PO Box 814.
Abstract
A study to evaluate the abundance dynamics of sporulating bacteria in rainwater was carried out in three sub-divisions of the city of Yaoundé during the period from February to August 2019. The bacteriological analysis were carried out after enrichment of the culture media by the technique of spreading on a Petri dish surface. The culture media used were the agars Luria-Bertani, Mossel and agar sulphitoreducer. The isolated bacteria were identified by standard methods for the assessment of water and wastewater.
The results of analysis of the abiotic variables showed air pollution. However, it has been noted that these waters are acid, in nature and are highly oxygenated. Some parameters such as temperature have been relatively stable, despite apparent spatial fluctuations. Bacteriological analysis revealed that these waters harbor a bacterial microflora consisting of bacteria of the genera Bacillus and Clostridium. Indeed, Bacillus cereus and Bacillus thuringiensis are the different Bacillus species identified with an average density of 8.29×102 CFU/100 mL for Bacillus thuringiensis and 8.13×102 CFU/100 mL for Bacillus cereus. In the Clostridium genus, only the species Clostridium perfringens has been identified with an average abundance of 2.93×102 CFU/100 mL. The monthly abundances of these bacteria undergo spatiotemporal fluctuations. Some physico-chemical parameters have influenced the distribution of these germs.Significant correlations between these germs have been obtained with temperature, electrical conductivity, turbidity and color. The degradation of the quality of these waters is favored by the atmospheric pollution due to the increase of the dust particles containing bacterial spores. These waters without any treatment, are not recommendable for the human consumption.
Keywords: rainwater, abiotic variables, bacterial spores, Yaounde.