Comparative antimicrobial evaluation of synthetic antibiotics and essential oils against human pathogenic bacteria and fungi

In pathological conditions, surgeries, or immunodeficiency, opportunistic pathogens that normally coexist harmlessly within the human body can escalate the human system, leading to infections ranging from mild to life-threatening. Combatting such infections requires reliance on either natural or synthetic antimicrobial molecules. Plant secondary metabolites, particularly essential oils, present a potential natural remedy for addressing these infections. The study aimed to qualitatively and quantitatively assess the efficacy of eight synthetic drugs and three essential oils against various pathogenic bacteria and fungi, including Staphylococcus aureus, Staphylococcus epidermidis, Mycobacterium smegmatis, Enterococcus faecalis, Malassezia furfur, and Candida albicans (K4-1). Our results showed that penicillin was highly effective against S. aureus and E. faecalis, while gentamicin was effective against S. epidermidis. Vancomycin exhibited antimicrobial activity against all bacteria except S. epidermidis. Notably, clotrimazole and amphotericin-B demonstrated potent inhibition of fungal pathogens. Essential oils, particularly lemongrass displayed prominent zones of inhibition against all the examined pathogens including the resistant strains. Palmarosa oil showed substantial inhibition at a concentration of 3% v/v.