Assessment of antibacterial potentials of violacein extract from Chromobacterium violaceum isolated from domestic and recreational water sources in Owerri, Nigeria

Abstract

This study was carried out with the aim of assessing the antibacterial potentials of violacein extracted from Chromobacterium violaceum isolated from domestic and recreational water sources in Owerri, Nigeria. Water samples were collected from different locations of the domestic water sources, five different swimming pools, and three borehole stations using sterile amber bottles. The isolation of C. violaceum was done using pour plate method on nutrient agar. The violet colonies of C. violaceum were counted, characterized and identified using standard microbiological and biochemical techniques. The mean viable bacterial counts were high. Water sample from Otamiri station-1 have the highest bacterial count (200 × 101 CFU/ml and 19.50 × 101 CFU/ml) respectively. Swimming pool 1 and 3 bacterial counts were (4.50 × 101 CFU/ml, 11 × 101 CFU/ml and 11.50 × 101 CFU/ml) respectively. For borehole 1, 2 and 3, swimming pool 2, 4 and 5, counts were (0.00 × 101 CFU/ml). Ethanolic extraction of violacein from C. violaceum was performed from a 48-hour culture broth. The sensitivity of the bacteria isolates to violacein was assayed on nutrient agar and nutrient broth by agar diffusion and broth dilution methods respectively. All the bacterial isolates were susceptible to the violacein extract at various concentrations, except MRSA that showed resistance to the violacein at 2.19mg/ml for extract from recreational water isolate and at 17.5mg/ml to 2.19mg/ml for extract from domestic water isolates. Conclusively, violacein has the potential to be used as an antibacterial compound for treatment of multidrug resistant bacterial infections.