Activities of Two Medicinal Plant Extracts on Multi-Drug-Resistant (MDR) ESKAPE Pathogens from Different Environments in Lagos, Nigeria

Abstract

The ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pose significant public health threats due to their widespread multidrug resistance. This study evaluated the antimicrobial activity of crude methanolic and aqueous extracts of Senna alata and Bryophyllum pinnatum against ESKAPE isolates obtained from clinical, animal, and environmental sources in Lagos State, Nigeria. Between September 2023 and February 2024, a total of 500 samples were collected: 350 clinical, 100 animal, and 50 environmental. Isolates were identified using standard microbiological methods and screened for antibiotic susceptibility, including phenotypic detection of extended-spectrum β-lactamase, AmpC β-lactamase, and carbapenemase production. Phytochemical analyses and agar disc diffusion assays were employed to evaluate the extract's composition and activity. The overall prevalence of ESKAPE isolates was 7.6% (38/500), distributed as 5.4% (19/350) in clinical samples, 10% (10/100) in animal samples, and 28% (14/50) in environmental samples. The isolates comprised 13 P. aeruginosa, 9 A. baumannii, 9 K. pneumoniae, 2 E. faecium, 2 S. aureus, and 3 Enterobacter spp. Over 70% exhibited multidrug resistance (MDR). Phenotypically, 23.7% (9/38) produced carbapenemases, and 7.9% (3/38) expressed ESBL and AmpC. Phytochemical screening identified eight classes of compounds; both methanolic and aqueous extracts of the plants contained alkaloids, flavonoids, steroids, and tannins. Senna alata methanolic extracts, richer in phytoconstituents than aqueous extracts, inhibited A. baumannii, P. aeruginosa, and K. pneumoniae with zones of 2–4 mm at 100–200 mg/mL, whereas B. pinnatum showed no activity. Results indicate Senna alata merits further investigation as a source of antimicrobials targeting multidrug-resistant ESKAPE pathogens.