HAS 1: A natural product from soil-isolated Streptomyces species with potent activity against cutaneous leishmaniasis caused by Leishmania tropica

Drug Discovery for Cutaneous Leishmaniasis: A Review of Developments in the Past 15 Years

Leishmaniasis is a group of vector-borne, parasitic diseases caused by over 20 species of the protozoan Leishmania spp. The three major disease classifications, cutaneous, visceral, and mucocutaneous, have a range of clinical manifestations from self-healing skin lesions to hepatosplenomegaly and mucosal membrane damage to fatality. As a neglected tropical disease, leishmaniasis represents a major international health challenge, with nearly 350 million people living at risk of infection a year. The current chemotherapeutics used to treat leishmaniasis have harsh side effects, prolonged and costly treatment regimens, as well as emerging drug resistance, and are predominantly used for the treatment of visceral leishmaniasis. There is an undeniable need for the identification and development of novel chemotherapeutics targeting cutaneous leishmaniasis (CL), largely ignored by concerted drug development efforts. CL is mostly non-lethal and the most common presentation of this disease, with nearly 1 million new cases reported annually. Recognizing this unaddressed need, substantial yet fragmented progress in early drug discovery efforts for CL has occurred in the past 15 years and was outlined in this review. However, further work needs to be carried out to advance early discovery candidates towards the clinic. Importantly, there is a paucity of investment in the translation and development of therapies for CL, limiting the emergence of viable solutions to deal with this serious and complex international health problem.

Novel Sources of Biodiversity and Biomolecules from Bacteria Isolated from a High Middle Ages Soil Sample in Palermo (Sicily, Italy)

The urban plan of Palermo (Sicily, Italy) has evolved throughout Punic, Roman, Byzantine, Arab, and Norman ages until it stabilized within the borders that correspond to the current historic center. During the 2012 to 2013 excavation campaign, new remains of the Arab settlement, directly implanted above the structures of the Roman age, were found. The materials investigated in this study derived from the so-called Survey No 3, which consists of a rock cavity of subcylindrical shape covered with calcarenite blocks: it was probably used to dispose of garbage during the Arabic age and its content, derived from daily activities, included grape seeds, scales and bones of fish, small animal bones, and charcoals. Radiocarbon dating confirmed the medieval origin of this site. The composition of the bacterial community was characterized through a culture-dependent and a culture-independent approach. Culturable bacteria were isolated under aerobic and anaerobic conditions and the total bacterial community was characterized through metagenomic sequencing. Bacterial isolates were tested for the production of compounds with antibiotic activity: a Streptomyces strain, whose genome was sequenced, was of particular interest because of its inhibitory activity, which was due to the Type I polyketide aureothin. Moreover, all strains were tested for the production of secreted proteases, with those belonging to the genus Nocardioides having the most active enzymes. Finally, protocols commonly used for ancient DNA studies were applied to evaluate the antiquity of isolated bacterial strains. Altogether these results show how paleomicrobiology might represent an innovative and unexplored source of novel biodiversity and new biotechnological tools. IMPORTANCE One of the goals of paleomicrobiology is the characterization of the microbial community present in archaeological sites. These analyses can usually provide valuable information about past events, such as occurrence of human and animal infectious diseases, ancient human activities, and environmental changes. However, in this work, investigations about the composition of the bacterial community of an ancient soil sample (harvested in Palermo, Italy) were carried out aiming to screen ancient culturable strains with biotechnological potential, such as the ability to produce bioactive molecules and secreted hydrolytic enzymes. Besides showing the biotechnological relevance of paleomicrobiology, this work reports a case of germination of putatively ancient bacterial spores recovered from soil rather than extreme environments. Moreover, in the case of spore-forming species, these results raise questions about the accuracy of techniques usually applied to estimate antiquity of DNA, as they could lead to its underestimation.

Cutaneous leishmaniasis in Tabuk, Saudi Arabia: epidemiological trends from 2006 to 2021

Introduction

cutaneous leishmaniasis (CL) is a vector-borne protozoan skin disease that affects all human ages and can pose extreme social and psychological impacts. This study aimed to reveal the epidemiological trends of CL in the Tabuk region, the Kingdom of Saudi Arabia (KSA), during the period from 2006 to 2021.

Methods

patients with CL, who were detected and registered at the regional Vector-borne Diseases Control Unit of the Tabuk province, between January 2006 and December 2021, were analyzed in this retrospective study. The patients´ data included their nationality, gender, and age, and their annual and month-by-month recorded patterns.

Results

a total of 1575 CL patients were reported during the said period. They were 53.1% Saudis and 46.9% non-Saudi expatriates with a ratio around 1.1: 1.0; and they were re-categorized as 83.17% males and 16.83% females with a ratio of 4.9: 1.0 (p <0.5). Additionally, the majority (1002/1575; 63.6%) of these CL patients were in age group of 15-45 years (p <0.5), and the lowest number was in age group of <5 years. Most importantly, there was a continuous annual and month-by-month record of these patients; reflecting CL endemicity in the Tabuk region of KSA.

Conclusion

the present findings imply that CL is endemic in the Tabuk region of KSA. As there is a recent increase in human immigration to this region, sustainable monitoring of CL and improving its control measures is warranted.