Microbiological Characterization of Diabetic Foot Infections in Southwestern Algeria and In Vitro Antimicrobial Potential of Saharan Plant Extracts (Juniperus phoenicea and Citrullus colocynthis)

Abstract

Diabetic Foot Infections (DFIs) present a severe clinical challenge compounded by the global rise of multidrug-resistant (MDR) pathogens. In hyper-arid environments like Southwestern Algeria, regional climatic factors significantly shape the wound microbiome. This prospective study evaluated the microbiological etiology of DFIs at the hospital facility of Béchar and investigated the in vitro antimicrobial activity of crude extracts from two Saharan medicinal plants, Juniperus phoenicea L. and Citrullus colocynthis (L.) Schrad. A total of 125 clinical isolates were identified using standard biochemical assays (API 20E), and their susceptibility patterns were evaluated per CLSI guidelines. The isolates exhibited a diverse microbial distribution: Gram-negative bacilli (38.4%), Gram-positive spore-formers (Bacillus spp., 36.0%), Gram-positive cocci (16.0%), and fungal strains (9.6%). Gram-negative pathogens showed high resistance to front-line therapeutics (ceftriaxone >60%), while the high prevalence of Bacillus spp. reflects environmental airborne contamination facilitated by regional sandstorms. In vitro testing demonstrated that J. phoenicea extract exerted potent broad-spectrum activity (inhibition zone up to 22.4 pm 1.2nmm; MIC = 18.75 mg/mL), whereas C. colocynthis displayed moderate efficacy primarily against Gram-positive strains (MIC = 62.50–125.00mg/mL). These findings underscore the distinct microbiological profile of DFIs in arid settings and support J. phoenicea as a candidate for developing topical phytotherapeutics.