[34] also observed that probiotic LAB and bifidobacteria of African and European origin were resistant to vancomycin, tetracycline, kanamycin, sulphamethoxazole, neomycin, nalidixan, apramycin and Selleck SB203580 colistin. Thus the potential health risks that could result from the transfer of antibiotic resistance genes from LAB reservoir strains to bacteria
in the resident microflora of the human gastrointestinal tract or pathogenic bacteria cannot be overlooked especially if the strains are to be introduced as live culture in food or feed products. To prevent the spread of antibiotics resistant genes, an application for European Food Safety Authority (EFSA) approval of microorganisms as feed www.selleckchem.com/products/sn-38.html additives or plant protection agents for instance, requires mandatory information on frequently used drugs resistant profiles of the bacteria [35]. Inter-genus and inter-species differences exist in antimicrobial susceptibility of bacteria as it has been indicated in some studies [29, 34]. Genotyping of microbial
species and their safety evaluations are hence essential in the microbiological risk assessment process prior to further study of these bacteria for different applications in the food and feed industry. The aim of the present study was to genotypically characterise 33 LAB isolated from African indigenous fermented food products and further evaluate their safety characteristics in terms of resistance to relevant antibiotics and haemolytic activities in
order to increase our at present limited knowledge on antibiotic resistance profiles of LAB from African indigenous fermented food products. Methods find more Bacterial strains, cultivation conditions and preliminary phenotypic characterizations The lactic acid bacteria strains used in this study were obtained from three different African indigenous fermented foods (Table 1). Stock-cultures were maintained in MRS broth (Oxoid Ltd., CM0359, pH 6.2 ± 0.2, Basingstoke, Hempshire, England) supplemented with 20% glycerol and stored at −80°C. Working cultures were made by inoculating 10 ml MRS broth with freeze-stock culture and then incubated at 37°C overnight in a standard incubator without agitation. The isolates were characterized by colony morphology and cells morphology using phase-contrast microscopy, CO2 production from Aspartate glucose in MRS broth with Durham tubes and catalase reaction with 3% H2O2. Table 1 Sources of isolation of 33 lactic acid bacteria investigated in this study Species and strains Source of isolation Raw materials used Reference Lb. plantarum Fermenting cocoa beans (FCB) Cocoa pulpa [8] L106, L547, L544, L415, L263, L260, L142, LA113 Lb. plantarum Koko sour water (KSW) Sorghum, maize, milletb [14] S1, S2 Lb. ghanensis FCB a [8] L489, L499 Leuc. pseudomesenteroides FCB a [8] L8 Lb. fermentum Dolo and pito wort (DPW) Sorghum, maizec [9] ZN7b-2, ZN7b-7 Lb. delbrueckii species DPW c [9] ZN7a-9 Lb.