Phytochemical screening and antibacterial activity of extracts from Teucrium polium and Equisetum telmateia growing in Algeria against multidrug-resistant bacteria

Background: Infectious diseases remain a major global health threat, exacerbated by the emergence of multidrug-resistant organisms that compromise the effectiveness of existing antibiotics. These resistance mechanisms, combined with the difficulties in developing new drugs, underscore the urgent need for alternative therapies. This work aimed to investigate the potential antibacterial activity of methanolic and ethanolic extracts from Teucrium polium and Equisetum telmateia growing in Algeria against multidrug-resistant bacteria and to determine their major classes of secondary metabolites involves in the pharmacological activities. Methods: antibiotic susceptibility pattern of clinical isolates and antibacterial activity was assessed by using disc diffusion method against nine bacterial strains, including reference strains (E. coli ATCC 25922, K. pneumoniae ATCC 700603, P. aeruginosa ATCC 27853, S. aureus ATCC 29213) and five clinical isolates. The phytochemical screening was performed using standard qualitative test. Results: antibiotic susceptibility testing revealed multidrug-resistant phenotypes, including extended-epectrum Beta-Lactamase producing strains (ESBL), high-level penicillinase producing strains and methicillin-resistant S. aureus (MRSA). The results of the antibacterial activity revealed that both T. polium extracts exhibited variable antibacterial activity against all test strains except K. pneumoniae ATCC 700603 at 200 mg/Ml. Similarly, E. telmateia extracts exhibited moderate to strong antibacterial activity at 200 mg/mL toward all tested strains except E.coli 1. The results of the phytochemical screening showed the presence of polyphenols, flavonoids, tannins, and terpenoids in both plant extracts. Conclusion: these findings indicate that both plant are rich in bioactive compounds with significant antibacterial potential, highlighting their promise as complementary sources of natural antimicrobial agents.