Aim: To test the hypothesis that lethal toxins of bacteria associated with sudden infant death syndrome (SIDS) can act synergistically. Methods: Bacteria occurring together in the nasopharynx of cases of cot death were studied. The lethal toxicity of crude toxin preparations was determined over a range of dilutions by injections into the chorioallantoic vein of the chick embryo. Toxin preparations of low lethality for the chick embryo SIDS model were then tested in combination. Results: Staphylococcus aureus toxin preparations showed low lethality when tested alone, even at low dilution. At 1 in 100 dilution S aureus toxin was lethal to one out of 15 chick embryos. Escherichia coli toxin preparations showed high lethality except on high dilution (1 in 80) when lethality fell to two out of 15 of chick embryos. When the same toxin preparations were tested simultaneously in combination, lethality rose to 14 out of 15. Similar findings were observed over a range of toxin dilutions. This finding was highly significant (p = 0-0012). Conclusions: That synergy between toxins can enhance the lethality of toxins elaborated by bacteria associated with SIDS.
A total of 115 samples made up of 42 (36.5%) rumen fluid, 36 (31.3%) cowdung and 37 (32.2%) soil samples were collected with the aid of sterile swab sticks except for rumen fluid samples which were collected by use of stomach tubes inserted into mouths of cows and by suction, liquor was collected into prewarmed thermo flasks under continuous flushing with carbondioxide. Soil samples were collected into sterile universal containers. All samples were obtained from abattoirs situated at three locations in Benin City, Nigeria. Samples were investigated for cellulolytic bacteria by Filter Paper Yeast Mineral broth method. Cellulase production was assayed by Carboxymethyl cellulose submerged broth culture while residual sugar yield and other cellulolytic activities were determined by 3, 5 -Dinitrosalicylic acid, Filter Paper, Microcrystalline and Viscometric methods. Cellullolytic bacterial organisms isolated from both soil and rumen fluids were Bacillus subtilis, Clostridium cellobioparum and Clostridium thermocellum. Pseudomonas aeruginosa was isolated from both soil and cowdung samples while Erwinia spp was obtained from both rumen fluid and cowdung samples. Bacillus circulans and Serratia spp were obtained from soil samples only. Clostridium thermocellum and Erwinia spp produced the highest and lowest cellulase yields respectively. All isolates at 40 o C and pH 6, recorded optimal sugar yields in culture broth of which Clostridium thermocellum recorded the highest. Lowest yields were recorded at 30 o C and pH 3 although there was significant difference in individual yields (P < 0.05). Clostridium thermocellum recorded optimal cellulolytic activities at 50 o C and pH 6. All isolates attained optimal cellulolytic activities at 32.6 ± 6.2 o C and pH 6.29 ± 0.9 with other broth cultural conditions kept constant. Implications of these findings are discussed.
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