Plant growth-promoting bacteria isolated from earthworms enhance spinach growth and its phytoremediation potential in metal-contaminated soils.

The aim of this study was to evaluate the impact of metal-tolerant plant growth-promoting bacteria (PGPB) isolated from the chloragogenous tissue of Aporrectodea molleri, which represents a unique habitat. Our objectives were to investigate their effects on the growth of Spinacia oleracea under heavy metal stress and assess their potential for enhancing phytoremediation capabilities. The experiment was conducted in an alkaline soil contaminated with 7 mg kg-1 of cadmium, 100 mg kg-1 of nickel, 150 mg kg-1 of copper, 300 mg kg-1 of Zinc, and mg kg-1 of 600 Manganese. The results showed that heavy metal stress considerably diminished root (42.8%) and shoot length (60.1%), biomass (80%), chlorophyll content (41%), soil alkaline (45%), and acid (51%) phosphatases (42%) and urease (42%). However, soil inoculation with bacterial isolates remarkably improved plant growth. Soil bioaugmentation increased spinach growth (up to 74.5% for root length, up to 106.3% for shoot length, and up to 5.5 folds for fresh biomass) while significantly increasing soil enzyme activity and NPK content. Multivariate data analysis indicated that soil inoculation with Bacillus circulans TC7 promoted plant growth while limiting metal bioaccumulation, whereas Pseudomonas sp. TC33 and Bacillus subtilis TC34 increased metal bioaccumulation in spinach tissues while minimizing their toxicity. Our study confirms that earthworms are a reservoir of multi-beneficial bacteria that can effectively improve phytoremediation efficiency and mitigate the toxic effects of heavy metals on plant growth. Further studies are needed to investigate the long-term effects and feasibility of using these isolates as a consortium in field applications.

Epidemiologic and clinical features of cutaneous leishmaniasis in southeastern Tunisia.

Species-specific diagnosis was performed in 66 patients with cutaneous leishmaniasis (CL) living in Tataouine focus in southeastern Tunisia. Leishmania DNA was extracted directly from dermal scrapings (n = 66) and from parasites obtained in culture (n = 12). Species were identified by using polymerase chain reaction-restriction fragment length polymorphism analysis for internal transcribed spacer region 1 and isoenzyme analysis. Leishmania tropica and L. major were identified in 31 (47%) and 35 (53%) cases respectively. Leishmania tropica CL cases were geographically scattered, and L. major CL cases were clustered. Lesions caused by L. tropica were mostly single (83.8%) and face-localized (55.8%), and lesions caused by L. major were multiple (57.1%; P < 0.001) and situated on limbs (83.7%; P < 0.001). For both species, most lesion onsets were reported during June-January. However, lesions that emerged during February-May were mainly caused by L. tropica (83.3%; P < 0.01). Moreover, the delay before seeking medical advice was higher for L. tropica infections than for L. major infections (P < 0.05).