Keywords: leptophages; Cas system; bacteriophages; Leptospira interrogans

Leptospira, which are known to be important disease-causing agents transmitted between animals and humans, results in significant illness and, in some cases, significant death in human populations. This study aims to examine the genomic structure of Leptospira interrogans serovar Copenhageni strain FDAARGOS_203 to identify the specific genetic factors that contribute to antimicrobial resistance (AMR) and defense against phages. The genome, consisting of two contigs totaling 4,630,574 base pairs, underwent thorough examination for protein-coding sequences, transfer RNA genes, and ribosomal RNA genes. A total of twenty-two antibiotic resistance genes that specifically target essential cellular processes such as cell wall synthesis, DNA replication, and protein synthesis have been identified. Significant among these were gidB, GdpD, and PgsA, each involved in separate aspects of antibiotic resistance. In addition, the investigation explored the defense mechanisms of bacteriophages, revealing the presence of defense islands that contain a range of anti-phage systems, including RM_Type_IV, PrrC, Borvo, CAS_Class1-Subtype-IC, and CAS_Class1-Subtype-IB. This comprehensive genomic analysis enhances our understanding of the molecular mechanisms that determine Leptospira's ability to adapt to various environments. The identified genetic factors linked to AMR and defense against phages not only enhance our scientific comprehension but also provide a basis for focused interventions to reduce the impact of leptospirosis.

Canine leptospirosis is a zoonosis of epidemiological importance. Dogs are recognized as primary reservoirs of Leptospira interrogans serogroup Canicola and a source of infection to the environment through urine. This study aimed to determine the presence of antibodies against Leptospira in canines from 49 municipalities in the Department of Antioquia, Colombia. We performed a cross-sectional study of dogs included in a neutering control program. We collected 1335 sera samples, assayed by a microagglutination test (MAT), and performed PCR detection in 21 urine samples. We also surveyed 903 dog owners. We found a seroreactivity of 11.2% (150/1335) in Antioquia with titers 1:50. Municipalities with the highest number of cases were Belmira (46.1%), Turbo (34.5%), and Concepción (31.0%). L. santarosai was identified by phylogenetic analysis in one urine sample from the municipality of Granada. The most important factor associated with a positive result was the lack of vaccination against leptospirosis (PR 3.3, p < 0.014). Environmental factors such as water presence and bare soil around the household were also associated with Leptospira seroreactivity in the Department of Antioquia. We reviewed a national epidemiological surveillance database for human cases in those municipalities. We found a correlation between the high number of cases in canines and humans, especially in the Uraba. Serological and molecular results showed the circulation of Leptospira. Future public health efforts in the municipalities with the highest numbers of seroreactivity should be directed towards vaccination to prevent animal disease and decrease the probability of transmission of Leptospira. Dogs actively participate in the Leptospira cycle in Antioquia and encourage the implementation of vaccination protocols and coverage.

Background: The febrile patient from tropical areas, in which emerging arboviruses are endemic, represent a diagnostic challenge and potential co-infections with other pathogens (i.e bacteria or parasites) are usually overlooked. Objectives: We present a case of an elderly woman diagnosed with dengue, chikungunya and Leptospira interrogans co-infection. Study Design: Case report. Results: An 87-year old woman from Colombia complained of upper abdominal pain, arthralgia, myalgia, hyporexia, malaise and intermittent fever accompanied with progressive jaundice. She had a medical history of chronic heart failure (Stage C, NYHA III), without documented cardiac murmurs, right bundle branch block, non-valvular atrial fibrillation, hypertension, and chronic venous disease. Her cardiac and pulmonary status quickly deteriorated after 24 hours of her admission without electrocardiographic changes and she required ventilatory and vasopressor support. In the next hours the patient evolved to pulseless electrical activity and then she died. Dengue IgM, NS1 ELISA, MAT for Leptospira interrogans and RT-PCR for chikungunya, were positive. Discussion: This case illustrates a multiple co-infection in a febrile patient from a tropical area of Latin America that evolved to death.

Leptospirosis is a globally distributed zoonotic disease caused by pathogenic bacteria of the genus Leptospira. This zoonotic disease affects humans, domestic, or wild animals. Colombia is considered an endemic country for leptospirosis; and Antioquia is the second department in Colombia with the highest number of reported leptospirosis cases. Currently, many studies report bats as reservoirs of Leptospira spp. but its prevalence in these mammals is unknown. In the present study we aimed to better understand the role of bats as reservoir hosts of Leptospira species and to evaluate the genetic diversity of circulating Leptospira species in Antioquia-Colombia. We captured 206 bats in the municipalities of Chigorodó (43 bats), Carepa (43 bats), Apartadó (39 bats), Turbo (40 bats), and Necoclí (41 bats) in the Urabá region (Antioquia-Colombia). Twenty bats were positive for Leptospira spp. infection (20/206 - 9,70%) and the species of infected bats were Carollia perspicillata, Dermatura rava, Glossophaga soricina, Molossus molossus, Artibeus planirostris, and Uroderma convexum. These species have different feeding strategies such as frugivorous, insectivores, and nectarivores. The infecting Leptospira species identified were Leptospira borgpetersenii (3/20 – 15%), Leptospira alexanderi (2/20 – 10%), Leptospira noguchii (6/20 – 30%), Leptospira interrogans (3/2 – 15%), and Leptospira kirschneri (6/20 – 30%). The results of this research show the importance of bats in the epidemiology, ecology and evolution of Leptospira in this host-pathogen association. This is the first step in deciphering the role played by bats in the epidemiology of human leptospirosis in the endemic region of Uraba (Antioquia-Colombia).

Unidentified abortion, of which leptospirosis, brucellosis and ovine enzootic abortion are important factors, is the main cause of disease spread between animals and humans in all agricultural systems in most developing countries. Although there are well-defined risk factors for these diseases, these characteristics do not represent the prevalence of the disease in different regions. This study predicts the unidentified abortion burden from multi-microorganisms in ewes based on artificial neural networks approach and GLM. Methods: A two-stage cluster survey design was conducted to estimate the seroprevalence of abortifacient microorganisms, and to identify putative factors of infectious abortion. Results: Overall seroprevalence of Brucella was 70.7%, while Leptospira spp. was 55.2%, C. abortus 21.9% and B. ovis 7.4%. Serological detection with the 4 abortion-causing microorganisms was determined only in 0.87% of sheep sampled. The best GLM is integrated by serological detection of serovar Hardjo and Brucella ovis in animals of the slopes with elevation between 2600 to 2800 meters above sea level from municipality of Xalatlaco, as well water supply, sheep pen built with materials of metal grids and untreated wood, with dirt and concrete floors, and bed of straw that remained independently associated with infectious abortion in ewes. Approximately 80% of those respondents did not wear gloves or masks to prevent the transmission of the abortifacient zoonotic microorganisms. Conclusions: Sensitizing stakeholders on good agricultural practices could improve public health surveillance. Further studies on the effect of animal-human transmission in such a setting are worthwhile to further support the One Health initiative.

Leptospirosis remains an important worldwide zoonotic disease caused by Leptospira spp affecting human and animals. This research aims to study the virulent-associated secreted proteins (protein secretome) of pathogenic Leptospira interrogans serovar Icterohemorrhagiae strain RGA (Leptospira RGA) transition from the environment to mammalian physiological osmolarity, temperature (37 °C) and carbon dioxide concentration (5% CO2) conditions for 24 h. Mass Spectrometry and bioinformatics approaches, we identified 69 potential secreted proteins from the culture supernatant of the Leptospira RGA isolate. We discovered transporters and porins such as phosphate porin, outer membrane efflux, ompA family protein, and polymer-forming cytoskeletal family protein under hyperosmotic condition. Under heat stress, degradation enzymes included zinc metallopeptidase, M23 family (LA3456, LA0709), Rhs family protein (LA1765), thermolysin metallopeptidase; / hydrolase family (LA1345, LA2501). Oxidative stress response proteins induced by osmolarity and temperature shifts included chaperon GrpE, DnaK (LA3705), antioxidants, i.e., thiol-specific redoxin, and peroxiredoxin (LA2809). In response to the in vivo transition, metabolic and other enzymes involved in energy production (COG:C), amino acid metabolism and transport (COG:E), and lipid metabolism and transport (COG:I), as well as moonlighting proteins functionally binding to plasminogen and fibronectin and regulating transcription, were also discovered. An overview of secreted proteins will supplement our understanding of Leptospira biology and pathogenesis during infection and also in response to environmental stimuli and their potential virulent determinants have the potential for developing leptospirosis vaccines and diagnosis.

Human leptospirosis cannot be investigated without studying zoonotic and environmental as-pects of the disease. The objectives of this study are to explore the abundance of Leptospira in dif-ferent climate zones of Sri Lanka and to describe the presence of Leptospira in same water source at different time points. First, water and soil samples were collected from whole-island, secondly, water sampling continued only in dry-zone, finally serial sampling of water from ten open wells was performed at five different time points. Quantitative PCR for water and metagenomic se-quencing for soil were used to detect Leptospira. In first component, 2 out of 12 water sites were positive and both are situated in wet-zone. Very small quantities of Genus Leptospira was detect-ed by metagenomic analysis of soil. Only 5 out of 26 samples were positive in the second compo-nent. Six, five, four, five, six wells were positive respectively in serial measurements of third component. All wells were positive at least one measurement while only one well was positive in all measurements. Closer to tank and higher distance from main road were significant risk fac-tors associated with well positivity. Presence of Leptospira seems not consistent indicating ran-dom abundance of Leptospira in natural environment.