Production and characterization of amylase by mixed cultures of Aspergilllus flavus and Aspergillus tamarii

This study evaluated the potentials of mixed cultures of Aspergillus flavus and A. tamarii used for enhanced amylase production. Amylase producing moulds were screened from the soil by plating on Remazol Brillant Blue-Starch agar. Out of the 800moulds screened, studies were conducted on amylase production of monocultures and mixed cultures of  non-aflatoxigenic Aspergillus flavus(A) and Aspergillus tamarii(C) by growing them on rice bran solid media at 30°C for 72h. The synergy between the two moulds was pronounced at 70°C and pH 6.0, 7.0 where the enzyme activity of the mixed culture(E) was 2.5 times higher than that of the monocultures. Storage stability with Cassava starch and Soyabean flour showed that the maximal enzyme stability of 95% was obtained with 3% (w/v) of Cassava starch at 4°C while 96% enzyme stability was  achieved with 4% (w/v) Soyabean flour at 30°C over a period of 8weeks. Thin Layer Chromatography of starch hydrolysates showed a mixture of glucose and maltose from extracts of A with only maltose from C  suggesting that A produced glucoamylase and á-amylase while C produced only α-amylase. This study shows that extracts of the mixed cultures contain enzyme complex that can be of high importance in the starch industry.Keywords: Microorganisms, amylase, pure Culture, mixed Culture

Production and characterization of amylase by mixed cultures of Aspergilllus flavus and Aspergillus tamari

This study evaluated the potentials of mixed cultures of Aspergilllus flavus and A. tamarii used for enhanced amylase production. Amylase producing moulds were screened from the soil by plating on Remazol Brillant Blue-Starch agar. Out of the 800moulds screened, studies were conducted on amylase production of monocultures and mixed cultures of non-aflatoxigenic Aspergillus flavus(A) and Aspergillus tamari (C) by growing them on rice bran solid media at 30\ub0C for 72h. The synergy between the two moulds was pronounced at 70\ub0C and pH 6.0, 7.0 where the enzyme activity of the mixed culture(E) was 2.5times higher than that of the monocultures. Storage stability with Cassava starch and Soyabean flour showed that the maximal enzyme stability of 95% was obtained with 3% (w/v) of Cassava starch at 4\ub0C while 96% enzyme stability was achieved with 4% (w/v) Soyabean flour at 30\ub0C over a period of 8weeks. Thin Layer Chromatography of starch hydrolysates showed a mixture of glucose and maltose from extracts of A with only maltose from C suggesting that A produced glucoamylase and \u3b1-amylase while C produced only \u3b1-amylase. This study shows that extracts of the mixed cultures contain enzyme complex that can be of high importance in the starch industry

Infection Control of Spatial Disseminated Multi-Antibiotics Resistant And Phylo- Diverse Staphylococcus Aureus Pathotypes

Focal dissemination of multi-antibiotic resistant (MAR) Staphylococci pathotypes regulated by agr functionalities was investigated and evaluated for infection control. Non-repetitive Staphylococcus aureus strains from soft and skin infections disseminated in several communities were recovered and biotyped, assayed for biofilm and profiled for antibiotic resistance. Strains were further genotyped for spa types, virulence and resistant genes; and mapped for geospatial distribution. Clonal diversity and functional accessory gene regulators ( agr ) were also evaluated. Staphylococcal infection was not significant with age group (p>0.05), but high rate of MSSA (53.0%) and MRSA (1.5%) was observed. Median resistance rates were significantly differ (p=0.001) but highest 75 th percentile and media resistance rates were observed in wound infection. Resistance rate of 78.8% at MIC 50 32μg/ml and MIC 90 128μg/ml to amoxicillin-clavulanate, and more than 40% resistance to ceftazidime, ciprofloxacin, gentamycin, ofloxacin, sulfamethoxazole and tetracycline with MIC 90 and MIC 50 at 32 μg/ml were observed. More than 0.83 multi-antibiotic resistance index (MARI) were observed among the strains that clustered into separate phylo-group expressing high beta- lactamase and strong biofilm production. Heterogeneous spa types t442 (wound and pus), t657 (wound), t091 (ear) and t657 (ear and wound) revealed high phylo- diversity. Only 4.6% pvl + MSSA-CC1 agr I, pvl + MSSA-CC5 (13.6%) and pvl + MRSA-CC7 agr II (4.6%), expressed enterotoxin; sea, sec, sed, sej, Leukocidins ( LukF-PV, lukD, lukE ), proteases ( aur, slpA sspB, sspE ) and resistance genes ( fosB, msr (A), bla mph(C),aphA3, sat, fosB, sdrM, Q7A4X2) . Phylogenetic related spa types of livestock origin, specifically bovine milk clustered with detected strains that were prevalent in urban communities with focal dissemination to other nearest suburbs. Clonal dissemination resistant pvl+ MAR MSSA-CC1 and MRSA- CC5 encoding agr were predominant in several peri-urban communities. This require adequate genosurveillance, population-target antimicrobial stewardship, extensive community health care intervention policy and well-structured infection control programs to prevent further focal dissemination

Clonal diversity and spatial dissemination of multi-antibiotics resistant Staphylococcus aureus pathotypes in Southwest Nigeria.

Spread of genetically diverse Staphylococcus aureus characterized with multi-antibiotic resistance and regulated by high level agr functionalities in several communities in southwest Nigeria was investigated and evaluated for infection control. Staphylococcus aureus pathotypes recovered from 256 cases including purulent pus from skin infections, soft tissue aspirates, wounds, otorrhea, eye, throat and endocervical infections were assayed for biofilm and antibiogram. Further genotyped with micro-array, mapped for geospatial distribution and evaluated for clonal diversity and functional accessory gene regulators (agr). Significant Staphylococci infection among the ages (OR:0.021, CI:0.545-1.914) and female gender with prevalence rate of MSSA (53.0%) and MRSA (1.5%) (OR:1.021, CI:0.374-1.785) were observed. More than 52.5% resistance rates to tetracycline and amoxicillin with significant median resistance were observed in all the infection cases (p = 0.001). Resistance rate of 78.8% at MIC50 32μg/ml and MIC90 128μg/ml to amoxicillin-clavulanate, and more than 40% resistance to ceftazidime, ciprofloxacin and tetracycline of MIC90 and MIC50 at 32 μg/ml were observed. Strains with multi-antibiotic resistance index above 0.83, high beta-lactamase and strong biofilm clustered into separate phylo-group. Heterogeneous t442 (wound and pus), t657 (wound), t091 (ear) and t657 (ear and wound) revealed high phylogenetic diversity. Only 4.6% pvl+ MSSA-CC1 agrI, pvl+ MSSA-CC5 (13.6%) and pvl+ MRSA-CC7 agrII (4.6%), expressed enterotoxin, leukocidins, proteases and resistance gene determinants. Livestock clonal types clustered with identified community-associated strains. Clonal dissemination of resistant pvl+ MSSA-CC1 and MRSA-CC5 encoding agr were predominant in several peri-urban communities where adequate geno-surveillance, population-target antimicrobial stewardship, extensive community structured infection control programs are needed to prevent further focal dissemination