Antibiofilm potential of aqueous extracts of Garcinia kola against Salmonella species in greater cane rat (Thryonomys swinderianus, Temmink 1827) from Badagry, Lagos State, Nigeria

Abstract

Biofilms encompass a cluster of microorganisms encased in a slimy matrix of extracellular polymeric substances, which imbibe antibiotic resistance. Salmonella specie is a major bacterial cause of food-borne diseases in both humans and animals. The prevalence of Salmonella species is increasing which may form biofilm, and bacteria that form biofilm may be more resistant to antimicrobial agents. This study is intended to determine the presence and antimicrobial susceptibility patterns of Salmonella species among greater cane rats and carry out the biofilm formation of isolated Salmonella species and dispersion using Garcinia kola. A total of 20 cane rats were obtained from a farm in Lagos state and roadside hunters. Samples of rectal swabs were collected aseptically for bacterial culture. Bacteria isolation was done with selective media using standard bacteriological techniques following pre-enrichment of the samples with buffered peptone water. Gram staining and biochemical tests were used for confirmation of the organisms. An antimicrobial susceptibility test was performed following standard protocol. Zones of inhibition were measured and categorized as totally sensitive and resistant. Nine (9) isolates of Salmonella species were obtained from rectal swabs of greater cane rats. A modified crystal violet assay was employed to develop biofilm and test the effect of a crude extract of Garcinia kola on biofilm dispersal. Data obtained from this study was subjected to statistical analysis using descriptive statistics and paired t-test at a level of significance of P ≤  0.05. The overall prevalence of Salmonella species obtained in this study was 45%. Antimicrobial study showed susceptibility of 77.8% for Chloramphenicol and 66.7% for Cefuroxime while all isolates were 100% susceptible to Amikacin and Gentamicin. The effect of Garcinia kola extract on different isolates at 430nm showed a significant difference (p= 0.0348) in biofilm formation in isolates with Garcinia kola extract when compared with isolates without extract. The effect of Garcinia kola extract on different isolates at 650nm elicited significant (p = 0.0216) biofilm inhibitions across the isolates. The antibiofilm activity displayed by Garcinia kola suggests its potential to serve as an alternative antimicrobial agent to combat drug resistant bacteria such as Salmonella species. However, further investigations should be carried out on the individual bioactive compounds to know the exact metabolites responsible for the antibiofilm activity of this bacteria species.