Extended-spectrum β-lactamases (ESβLs) are a rapidly evolving group of β-lactamases which share the ability to hydrolyze third-generation cephalosporins and aztreonam yet are inhibited by clavulanic acid. In this study, the aim was to determine the susceptibility of ESβL producing clinical isolates of Escherichia coli across various antimicrobial agents according to the Clinical Laboratory Standard Institute (CLSI) new breakpoints. Sixty five clinical isolates of Escherichia coli were collected from a Tertiary Hospital in Nigeria of which forty six ESβL-producing isolates emerged. Presence of ESβL was determined by double- disk synergy test, DNA extraction and amplification of ESβL genes- bla_SHV, bla_TEM, bla_CTX-M by Polymerase Chain Reaction. Susceptibility of the ESβL-producing isolates was determined by the CLSI agar diffusion method. Utilizing the CLSI new breakpoints, 76.09%, 73.91%, 73.91% and 63.04% were resistant to Cefotaxime, Ceftazidime, Aztreonam and Cefepime respectively. While, 19.6%, 15.2%, 21.7% and 40% were susceptible to Cefotaxime, Ceftazidime, Aztreonam and Cefepime respectively. Furthermore, though a significant number of ESβL-producing isolates were susceptible to carbapenem; ESβL isolates that harboured the blaSHV, blaTEM, blaCTX-M genes showed resistance to carbapenem. Thus, carbapenem-resistant ESβL-producing isolates emerged from this study. In conclusion, Nigeria is a developing country affected by the spread of bacterial strains harbouring ESβL and with the emergence of carbapenem resistance; it is certain to create significant therapeutic problems as carbapenem is the drug of choice for serious infections caused by ESβL-producing Escherichia coli.

The optimisation of production and freeze-drying of P. fluorescens used as a bio-control agent was investigated. P. fluorescens BTP1 was produced in a bioreactor with different against-pressure value (0.1 and 0.3 bar for bioreactor 1 and 2 respectively) and cells were harvested during the stationary phase (2Hrs. and 4Hrs. for bioreactor 1 and 2 respectively). A mixture of protective compounds were tested for freeze-drying, and the highest result was found for glycerol and maltodextrine (26%) followed by glycerol, maltodextrine and ascorbic acid (18.9%) and glycerol with ascorbic acid (8.5%). We observed that the survival rate is better at 4°C than at room temperature and those powders with protective compounds have a survival rate greater than the powder without protective compounds during storage.

Pseudomonas sp.593 is a soil-dwelling bacterium unable to elicit any hypersensitive response (HR) in tobacco or soybean. The hrpZ gene, encoding an abundant Type III secretion system (T3SS) dependent protein, was cloned from a phytopathogen Pseudomonas syringae pv. syringae Van Hall CFCC 1336. The HrpZ harpin expressed in E. coli was purified to homogeneity, and used to raise polyclonal anti-HrpZ rabbit serum. The cloned hrpZ gene was then introduced into the soil bacterium Pseudomonas sp.593 via transformation of the plasmid pMEK-hrpZ. Western blotting and HR assay showed that the hrpZ-transformed Pseudomonas sp.593 was not only able to secret HrpZ harpin but also elicited a strong HR reaction in tobacco and soybean just as P. syringae did. In addition, bacterial cells were able to grow and multiply in the HR zone. Our results demonstrate that an avirulent strain can become a virulent-like pathogen, or a pathogen strain can broaden its host range once a single exogenous hrpZ gene cloned from a phytopathogen is introduced into a bacterium displaying phylogenetic diversity.

Strains of Colletotrichum kahawae from different coffee growing areas in Tanzania, Kenya and Cameroon were studied for their different characters. Characterization was done through the application of iso-enzyme whereby morphological attributes were studied to determine variability of C. kahawae. Application of iso-enzymes involved extraction of proteins from the mycelia of each of the strain and the content was determined using Bio-Rad protein assay kit. The strains were Tanzania (14), Kenya (2) and Cameroon (1), and Colletotrichum gloeosporioides. The protein content of C. kahawae strains were compared for their reaction to iso-enzymes based on the activity of esterace, acid and basic phosphotase using the technique of isoelectic focusing electrophoresis (IEF). It was possible to detect a high esterase activity portraying many bands per strain of C. kahawae, but lower in the case of basic and acid phosphatase. However all enzymes revealed polymorphisms. The data matrices from enzymes pattern were formed by identifying the presence or absence of bands. A phenogram based on the estimate similarity coefficients was constructed by un-weighed pair group methods (UPGMA) using the computer software package NTSYS-PC version 2.02. The original similarity matrix was compared with the cophenetic value matrix generated from the systems of clusters. The cophenetic coefficient (r) was estimated and used as a measure of the goodness of fit. The results obtained by cluster analysis on C. kahawaeCam1 strain shows that iso-enzymatic profile of the strain is different from the rest. In the Tanzania population studied two groups were formed and C. kahawae strain T3 seemed to be different from the rest of the strain. Characteristics of Colletotrichum strains collected from different coffee growing areas were observed after 10 days of growth on MEA in darkness at temperature ranges between 15°C to 30°C. The morph cultural characteristics used to study variability of Colletotrichum spp were cultural texture, conidia shape and sizes, and growth rate. Out of 30 Colletotrichum spp isolated from diseased green coffee berries, 25 isolates were identified as Colletotrichum kahawae producing dark grey cottony, oval conidia morphology and slow growth rate. Five isolates identified as Colletotrichum gloeosporioides; growth rate ranged from 7.3 to 8.8 mm and C. kahawae ranged from 5.0 to 5.5 mm per 24 hr. at 25oC. This shows that the growth rate of C. gloeosporioides was always more rapid than that of C. kahawae. This shows that the growth rate analysis is a useful method separating C. kahawae from C. gloeosporioides. Conidia sizes of C. kahawaestrains were variable even within one strain. However based on this study, variability in spore size can not be used to distinguish the strains of C. kahawae.

Twenty yeast strains were isolated from traditional Indian fermented foods (idli and jalebi batter) and were screened for various probiotic properties. Seven of these isolates could survive in conditions similar to the gut with a survival rate as high as 100% at pH 2.0-2.5 and bile salt concentration of 1%. They were able to grow at 37ºC and were resistant to commonly used antibiotics. Auto-aggregation ability and cell surface hydrophobicity was observed to be high for all of the isolates. Antimicrobial action was exhibited by these isolates against enteric pathogens (i.e., E. coli, Salmonella sp., Staphylococcus aureus, Vibrio cholerae and Pseudomonas sp.). Further, they were observed to produce phytase, β-galactosidase, L-asparaginase, protease and lipase, thus could be useful in degrading anti-nutrients and improving digestion. Most of them were vitamin B12 (except J15) and exopolysaccharide producers. All of them had the ability to assimilate cholesterol in the range 57-88.5%. None of the strains produced DNase and gelatinase, thus ascertaining their safe use. These isolates were identified as Saccharomyces cerevisiae, Candida tropicalis, Aureobasidium sp. and Pichia manschuria