Antibacterial kinetics and phylogenetic analysis of aloe vera plants

Abstract

BACKGROUND: Uncontrolled use of antibiotics has resulted in the emergence of resistant bacteria. It has necessitated the evaluation of antibacterial activities and phylo-diversity of Aloe vera (also called Aloe barbadensis) plants as antimicrobial agent in Nigeria. METHODS: Biotyped enteric bacilli of 251 strains obtained from fecal samples of patients with various gastro-intestinal complications are profiled for antibiogram. Resistant biotypes were assayed for susceptibility to A. vera latex and further evaluated for time-kill kinetics and phylo-diversity. RESULTS: More than 30% of enteric bacilli, including Citrobacter freundii, Escherichia coli, and Proteus mirabilis, were resistant to cotrimoxazole, ciprofloxacin, and tetracycline, respectively, at minimum inhibitory concentration (MIC) >16 μg/ml (p = 0.004). A. vera latex significantly inhibited 39.5% resistant enteric biotypes with a significant average reduction of the viable count at 1 × MIC and 2 × MIC to <3.0 Log10CFU/mL after 24 h. Flavonoids, alkaloids, terpenoids, and anthraquinine in anti-enteric sap significantly correlated and regressed with antibacterial activity (p < 0.05), while two of the antimicrobial A. vera plants showed phylogenetic relatedness with other homologous. CONCLUSION: Antibacteria efficacy of some Nigerian A. vera latex could provide alternative therapy, while its phylodiversity and genomic profiling would offer a promising avenue for identification and development of antimicrobial agents as drug candidates for natural antibiotics.