Inhibition of dehydrogenase activity in pathogenic bacteria isolates by aqueous extract from the unripe fruit peels (called the bark) and leaves of Musa paradisiaca var sapientum were investigated via dehydrogenase assay using 2,3,5-triphenyl tetrazolium chloride (TTC) as the electron acceptor. Pure cultures of Staphylococcus and Pseudomonas species were exposed to varied concentrations of the extract [0-2000 µg/ml]. The extracts exhibited concentration dependent response against the tested organisms. Dehydrogenase activities (mg Formazan/mg cell dry weight/h) in the Gram-positive Staphylococcus sp. and Gram-negative Pseudomonas sp. were 1.125 ± 0.056 and 0.740 ± 0.040, respectively, and were progressively inhibited in the pure cultures. Threshold inhibitory concentrations (IC 50) of M. paradisiaca bark extract were 143.5 and 183.1 µg/ml against Staphylococcus and Pseudomonas species, respectively, while the threshold inhibitory concentrations (IC 50) of M. paradisiaca leaf extract were 401.2 and 594.6 µg/ml, respectively. The IC 100 of the leaf extract against Staphylococcus and Pseudomonas species were 1850 and 2000 µg/ml respectively, while the bark could not completely inhibit the organisms at the tested concentrations. The bark and leaves of M. paradisiaca may be an available source of raw material for the production of chemotherapeutic agents against pathogenic bacteria.

Effect of plantain (Musa paradisiaca (L) AAB genomic group) peel and stalk extracts were investigated using percentage inhibition test. Complete inhibition of growth (100%) was observed for Aspergillusniger, Aspergillus oryzae and Rhizopus stolonifer at 1.0 mg/ml concentration of stalk extract. Peel extract inhibited A. niger 100%, A. oryzae 76.67% and R. stolonifer 56.67% at the same concentration. As concentration reduces, growth inhibition reduces also up to the minimum inhibitory concentration. The results of this work justify that the plant extracts were able to inhibit and kill the growth of spoilage fungi and this implies that the extract in appropriate doses can be used in food preservation and to treat infections caused by this spoilage fungi. The results further justify the claim that Musa paradisiaca (L) stalk and peel extract demonstrated antifungal action in which methanol was seen to be a better solvent for extracting active ingredients from medicinal plants considering the high susceptibility of test organisms to methanol extract than ethanol extract used in this study. Phytochemical screening showed the presence of hydrogen cyanide, tannin, alkaloid, steroid, saponin and flavonoid. The growth inhibition of A. niger, A. oryzae and R. stolonifer by Musa paradisiaca peel and stalk methanol and ethanol extract in this study suggest the presence of antifungal substance in the plant tissue and the possibility of using the extract to control plant pathogens especially where the spoilage fungi used in this study are involved.

Detection of AmpC-mediated resistance in Gram negative organisms poses a problem due to misleading results in phenotypic tests. There are no recommended guidelines for detection of this resistance mechanism and there is a need to address this issue as much as the detection of extended spectrum beta lactamases (ESBLs) since both may co-exist and mask each other. Several methods have been used to detect the presence of AmpC β-lactamase production in some isolates but most of these methods are not reliable. There is a need for a reliable method of evaluating the presence of AmpC βlactamases in clinical isolates. A total of 81 consecutive non repetitive clinical isolates of Escherichia coli (n=40) and Klebsiella spp. (n=41) were screened for AmpC production by disc diffusion method using cefoxitin (30 µg) disc and confirmed by inhibitor based test using boronic acid as inhibitor. A total of 16 E.coli isolates (40%) and 16 Klebsiella isolates (39.02%) screened harbored AmpC enzymes, of which 43.75% of E.coli and 56.25% of Klebsiella isolates coproduced ESBL enzymes. Pure AmpC production was observed in 56.25% of E.coli and 43.75% of Klebsiella isolates. The inhibitor based test was useful in identifying cefoxitin susceptible AmpC producers and could also effectively differentiate ESBL from AmpC producing isolates.

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Gari agar was prepared by weighing 28 g of Gari, 14 g of agar powder and 8 g of Hibiscus rabdariffa powder to 1 L of sterile water. A conventional media, Sabouraud Dextrose Agar (SDA) was prepared as control according to manufacturer's procedure. Aliquot of appropriate dilutions of 1 g of agricultural soil was inoculated onto SDA and Gari agar by pour plate technique and spread plate technique. After 2 days and 4 days of inoculation, the growth of moulds was examined. Fungal colonies on Gari agar were very healthy and compared favourably with fungal growth on Sabouraud dextrose agar which is a conventional medium. Gari agar produced healthy moulds as determined by diameter of growth. Furthermore, conventional media (SDA) supported the growth of bacteria while Gari agar inhibited the growth of bacteria and promoted that of fungi. Cassava can be successfully grown in poor soils with low labour requirement, low capital and ease of cultivation. Gari extract agar can now be used successfully for quantitative count of moulds. The result of this study will go a long way in solving the problem of high cost of conventional media used as culture media for mycological studies.

This study evaluates the antimicrobial activity of the leaf extracts of Moringa oleifera and Jatropha curcas against Staphylococcus aureus and Escherichia coli. Different concentrations of the extracts were subjected to these organisms in which Moringa oleifera showed a higher zone of inhibition on Staphylococcus aureus (2.8 cm) while on E. coli (2.4 cm) while Jatropha curcas showed a higher zone of inhibition on E. coli (2.6 cm) while on S. aureus (1.80 cm). The minimum inhibitory concentration (MIC) of Moringa oleifera extract on E. coli and S. aureus were 0.250 mg/ml and 0.125 mg/ml respectively while MIC of Jatropha curcas extract on test organisms was 0.125 mg/ml. The quantitative phytochemical screening in g/kg revealed the presence of flavonoid 36 and 21, alkaloids 92 and 39, tannins 7.4 and 5.6, saponins 115.0 and 53.5, cyanogenic glycosides 8.4 and 14.5 for M. oleifera and J. curcas respectively. The observed antimicrobial properties could be due to the presence of these bioactive compounds and further substantiates the use of Moringa oleifera and Jatropha curcas leaf extracts in medicine. The extracts in correct doses can successfully be used in vivo to inhibit and eventually kill the test bacteria used in this study.

The study investigated the optimu m conditions of temperature, pH, inoculu m size and time of incubation on bacterial p rotease production. Protease producing bacterial species were isolated fro m abattoir soil and identified as Micrococcus luteus and Bacillus species. The optimu m conditions observed for protease production was 37℃ at pH 7, with 1% inoculu m in the mediu m for 24 h of incubation in Micrococcus luteus while in Bacillus species, the optimu m conditions observed was 47℃ at p H 9, with 2% inoculu m concentration in the med iu m for 96 h of incubation. Generally, temperature and pH had more effect on the protease activity of Micrococcus luteus while inoculu m concentration and time of incubation had more effect on the protease activity of Bacillus species. The study gave evidence that these bacterial isolates could be potentially applied in biotechnological processes.

This study evaluates the antimicrobial activity of the leaf extracts of Moringa oleifera and Jatropha curcas against Staphylococcus aureus and Escherichia coli. Different concentrations of the extracts were subjected to these organisms in which Moringa oleifera showed a higher zone of inhibition on Staphylococcus aureus (2.8 cm) while on E. coli (2.4 cm) while Jatropha curcas showed a higher zone of inhibition on E. coli (2.6 cm) while on S. aureus (1.80 cm). The minimum inhibitory concentration (MIC) of Moringa oleifera extract on E. coli and S. aureus were 0.250 mg/ml and 0.125 mg/ml respectively while MIC of Jatropha curcas extract on test organisms was 0.125 mg/ml. The quantitative phytochemical screening in g/kg revealed the presence of flavonoid 36 and 21, alkaloids 92 and 39, tannins 7.4 and 5.6, saponins 115.0 and 53.5, cyanogenic glycosides 8.4 and 14.5 for M. oleifera and J. curcas respectively. The observed antimicrobial properties could be due to the presence of these bioactive compounds and further substantiates the use of Moringa oleifera and Jatropha curcas leaf extracts in medicine. The extracts in correct doses can successfully be used in vivo to inhibit and eventually kill the test bacteria used in this study.