Water pollution bacteria in Kenya

Abstract

WATER POLLUTION BACTERIA IN KENYA An investigation into the growth and sporulation requirements of two laboratory strains of Clostridium perfringens was undertaken in order to elucidate the type of nutrients the natural environment must provide to support the se activities. Variation in nutritional requirements between C. perfringens strain 6DO and Colo was observed. Isoleucine, lysine, methionine, serine, alanine, aspartic acid, riboflavin and uracil reported by previous workers as required nutrients were not absolutely essential for these strains. Alanine, was required as a stimulant for growth. Interaction among amino acids occurred, and these are discussed. Growth was not detected in a nitrogenous medium free of carbohydrate, nor could lactic acid, pyruvic acid, succinic acid or oxaloacetic acid be utilized for growth. Methionine was required by both strains for sporulation; one strain required in addition riboflavin, isoleucine, serine and lysine. It was demonstrated that some nutrients, though not essential, are required either for thermoresistance or better spore crop production. The inhibition of sporulation in glucose medium was shown to be due to the development of high hydrogen ion concentration and not to the presence of antagonistic intermediate or organic end products of fermentation. Studies on germination and growth of C. perfringens in filtersterilized river water at room temperature (18 to 22 C) showed that multiplication of the organism did not occur. Germination was, however, detected and microcycle sporogenesis was indicated. A selective and differential solid medium containing glucose, sodium sulfite, basic fuchsin and antibiotics for the recovery of C. perfringens from suspensions, using membrane filter techniques, was developed. The importance of the use of blood in the medium, or an agar overlay, is discussed. Employing membrane filter technique, a comparative study of C. perfringens, total bacteria, total coliform and fecal coliform organisms as indices of water pollution was undertaken while investigating the water quality of wells, boreholes, springs and rivers in Kiambu District, Kenya. The presence of fecal coliforms in water was the most reliable index of fecal contamination. C. perfringens was not consistently detected in water known to be polluted with fecal matter. The possible factors influencing the apparent absence of the organism are discussed. Examination of water from the various sources In Kiambu District showed that only water from boreholes was potable. There was no variation in the quality of water from wells between the dry and rainy seasons, but a dilution effect was noticed in some parts of the Nairobi River. The pH of river water was also affected by surface runoff during the rainy season.