Journal of Applied Life Sciences International

Background: Drug-resistant bacteria are a major threat for hospitals, complicating hospital-acquired infections.

Objective: To promote medicinal plants as alternative therapeutics to current conventional antibacterial agents which are increasingly tolerated by bacteria, the present investigation assessed the antibacterial potentials of the hydroethanolic extract recovered from dried leaves of Cajanus cajan (L.) Millsp., on multidrug-resistant bacteria isolated from a healthcare facility environment.

Methods: For this purpose, multidrug-resistant (MDR) bacteria were isolated from specimens collected from the “Université des Montagnes” Teaching Hospital environment, where local bacterial flora were previously found to express high rates of resistance to conventional antibacterial agents and to disinfectants. The antibacterial potential was investigated through the determination of the minimal inhibitory and bactericidal concentrations of the extract from which a few groups of secondary metabolites were screened.

Results: Qualitative phytochemical screening revealed the presence of flavonoids, polyphenols, quinones, tannins and terpenes in the extract used. On a pool of 64 multidrug-resistant bacteria isolates (Gram-positive rods: 23; Gram-positive cocci: 20; Gram-negative rods: 21), the minimal inhibitory and bactericidal concentrations of the hydroethanolic extract from dried leaves of Cajanus cajan (L.) Millsp. ranged from 1.465 through 93.75 mg/mL, and from 6.25 through 175 mg/mL, respectively. Gram-positive rods exhibited the highest tolerance (MIC = 69.4185±17.4405 mg/mL; MBC = 116.8478±35.677 mg/mL), while Gram-positive cocci were most susceptible (MIC = 3.2663±1.6854 mg/mL; MBC = 12.0701±5.7882 mg/mL). Amongst the Gram-negative rods, higher resistance was observed with Pseudomonas (MIC = 43.2292±3.0725 mg/mL; MBC = 73.9583±11.2962 mg/mL), and Enterobacteriaceae (MIC = 12.2342±3.6743 mg/mL; MBC = 22.1153±6.3016 mg/mL). Eventually, this extract expressed a bactericidal potential on 78.125% of subjected isolates.

Conclusion: The antibacterial assays revealed a significant antibacterial activity against MDR Gram-positive cocci and Gram-negative rods, which are due to bioactive compounds present in the plant as revealed by the phytochemical screening. Hence, the current findings indicate that this extract could effectively serve in controlling environmental antibiotic-resistant bacteria which are threat in healthcare settings and to public health at large.