The Heavy metal tolerance screening and beta-lactamase production in bacteria isolated from Abattoir wastewater and it's contaminated soil in Adamawa State.

Abstract

Bacterial adaptability enables them to tolerate many stressors like antibiotics and heavy metals, however, triggering the phenomenon of acquisition of heavy metals resistance also incite to antibiotics which is aided by their ability to produce enzymes. This study seeks to screen heavy metal tolerance, determine beta-lactamase and metalo-beta- lactamase activities from bacteria isolated from Abattoir wastewater and it's contaminated soils in Adamawa State. Samples were analyzed using standard microbiological techniques. Bacterial isolates with MAR indices above 0.4 were screen for tolerance to heavy metals at 50,150 and 300ppm. Extended beta- lactamase activity of bacterial isolates that are heavy metal tolerant was performed on Muller Hinton agar using Kirby Bauer double disc diffusion method according CLSI, 2020. The metallo-beta- lactamase activity was determined using Imipenem+EDTA combined disc . All the isolates subjected to the heavy metal screening test showed levels of growth except Chromobacteruim spp which showed no growth at all the concentrations of the heavy metals. However, Pseudomonas aeruginosa and Escherichia coli were able to grow in the presence of all the concentrations of the heavy metals (Cu, Zn, Pb, Co and Fe). Pseudomonas aeruginosa and Escherichia coli were tolerant to at least one of the concentrations of the metals except zinc. Extended beta-lactamase productions and detection of metallo-beta-lactamase activity showed the isolates were positive for the test at different intensities with respect to the clarity of the zones but P. aeruginosa and E.coli had the highest zones greater than 5mm with Amoxicillin clavulanic acid.. Same were positive for for metallo-beta-lactamase activity but also at different levels with respect to the specification of the clarity of the zones. E. coli showed the highest increase in with Imipenem EDTA combined disc greater than 7mm, followed by P. aeruginosa. The potentials can give prior information about the two isolates with respect to the hazard they present in the immediate environment.