Leptospira noguchii
1. Classification
Higher order taxa
Bacteria; Spirochaetota; Spirochaetia; Leptospirales; Leptospiraceae; Leptospira[1]
2. Description and significance
Leptospira noguchii are Gram-negative spirochete-shaped bacteria[2]. L. noguchii is an emerging pathogen that has been linked to the pathogenic disease Leptospirosis, which is known to affect humans and other mammals, most importantly cattle[2]. It has been directly linked to an outbreak with reproductive disorders in a Brazilian dairy goat flock in 2022[3].
3. Genome structure
The genome size of L. noguchii (Serovar Panama, Strain U73) is 4.7 Mb and has a GC content of 35.5%[4]. The genome contains 4034 total genes with 3798 coding genes. Genes relevant to virulence factors included lipoprotein and immunoglobulin-like protein genes lipL41, lipL36, lolC/D, and ligA which are shared by L. interrogans. Several antimicrobial resistance genes are identified which includes efflux pumps (mdtA, mdtB, norM) and metal resistance genes (sugE, czcA, czcD). L. noguchii serotypes were sourced from various wild and domestic animals, such as cattle, and from human patients. Three serotypes were previously established as Bataviae, Australis, and Autumnalis and were confirmed by the sequencing of the rpoB gene[5]. A recent phylogenetic study yielded sequencing results of the secY locus, identifying additional L. noguchii serogroups Panama and Pyrogenes[6].
4. Cell structure
L. noguchii is a spirochete and Gram-negative bacterium, which has a peptidoglycan cell wall surrounded by an outer membrane of lipopolysaccharide (LPS)[2]. They tend to range from 0.1 μm by 6 μm to 0.1 μm to 20 μm[7]. Leptospiral species differ from most pathogenic spirochetes, having a more LPS-rich outer layer[8]. Lipid A of leptospires is unique in that it contains a phosphorylated and methylated glucosamine disaccharide unit[2]. Leptospires have two periplasmic flagella which allow motility, as well as distinct hooked ends identified through electron microscopy[2].
5. Metabolic processes
L. noguchii is a chemoorganotrophic organism and obligate aerobe which metabolizes long chain fatty acids as its main carbon source[2]. Alcohol and long-chain fatty acids are the primary carbon and energy sources for L. noguchii[11]. Leptospira also produces catalase, oxidase, and peroxidase which are key in metabolizing compounds during oxidative phosphorylation[11].
6. Ecology
L. noguchii grows best at 28-30°C[2]. In optimal conditions, L. noguchii has a generation time of about 6-16 hours[11]. While L. noguchii is mostly found across the United States and Latin America, the complete biogeographic distribution of L. noguchii remains unknown. The microbe is often recovered from wildlife hosts, which act as a reservoir for the microbe[9]. Animals can maintain chronic infection caused by L. noguchii and ultimately spread the microbe through their urine[10]. After an infected organism urinates, L. noguchii can spread and enter other organisms through open wounds or when the new organism ingests the microbe[10].
7. Pathology
L. noguchii is a pathogenic microorganism that causes leptospirosis in various mammalian species. It enters through openings in the skin, either through mucous membranes or abrasions. It then travels through the bloodstream to the urinary system, which it attaches to through the use of proteins such as LigA, LigB, and LipL32[11]. When leptospires in the blood and tissues reach a critical level, lesions and fever appear. Localized ischemia can in severe cases cause pulmonary damage and hemorrhaging, resulting in jaundice. Tissue damage with leptospirosis, though severe, may be reversible and reparable especially in the kidneys and liver[2]. The mechanisms of tissue damage are not well understood, in particular the molecular basis for virulence[2]. One of the earliest incidences of L. noguchii infection isolated from humans was characterized through the Fort Bragg strain (Serovar Autumnalis) from soldiers in Fort Bragg, North Carolina[12].
8. Current Research
It has been recently discovered that bats can be reservoirs of the Leptospira spp. 30% of the highly diversified Leptospira spp. found in bats were L. noguchii; this host-pathogen association reveals the important roles bats can play in the epidemiology, ecology, and evolution of the bacteria[13]. Other researchers have found a new molecular mechanism that could better genetically identify different serovar types of L. noguchii. Through whole genome sequencing of different strains of L. noguchii, horizontal gene transfer of the rfb cluster, which contains many LPS biosynthesis-encoding genes, has been shown to be strongly correlated with the serovar designation of L. noguchii[14].
9. References
[1] U.S. National Library of Medicine. (n.d.). Taxonomy browser (leptospira noguchii). National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=28182&lvl=3&keep=1&srchmode=1&unlock&lin=f&log_op=lineage_toggle
[2] Adler, B., & de la Peña Moctezuma, A. (2010). Leptospira and Leptospirosis. Veterinary Microbiology, 140(3–4), 287–296. https://doi.org/10.1016/j.vetmic.2009.03.012
[3] Aymée, Luiza et al. “Leptospira noguchii associated to reproductive disease in ruminants.” Transboundary and emerging diseases vol. 69,5 (2022): 3103-3108. doi:10.1111/tbed.14377.
[4] Moreno, Luisa Z., et al. “Draft genome sequence of Brazilian Leptospira noguchii serogroup Panama strain U73, isolated from cattle.” Genome Announcements, vol. 3, no. 5, 2015, https://doi.org/10.1128/genomea.01179-15.
[5] Silva EF, Cerqueira GM, Seyffert N, Seixas FK, Hartwig DD, Athanazio DA, Pinto LS, Queiroz A, Ko AI, Brod CS, Dellagostin OA. Leptospira noguchii and human and animal leptospirosis, Southern Brazil. Emerg Infect Dis. 2009 Apr;15(4):621-3. doi: 10.3201/eid1504.071669. PMID: 19331754; PMCID: PMC2671420.
[6] Loureiro AP, Jaeger LH, Di Azevedo MIN, Miraglia F, Moreno LZ, Moreno AM, Pestana CP, Carvalho-Costa FA, Medeiros MA, Lilenbaum W. Molecular epidemiology of Leptospira noguchii reveals important insights into a One Health context. Transbound Emerg Dis. 2020 Jan;67(1):276-283. doi: 10.1111/tbed.13349. Epub 2019 Sep 17. PMID: 31484225.
[7] Cullen, P. A., Haake, D. A., & Adler, B. (2004). Outer membrane proteins of pathogenic spirochetes. FEMS Microbiology Reviews, 28(3), 291–318. https://doi.org/10.1016/j.femsre.2003.10.004
[8] Haake, D. A., & Zückert, W. R. (2014). The leptospiral outer membrane. Current Topics in Microbiology and Immunology, 187–221. https://doi.org/10.1007/978-3-662-45059-8_8
[9] Martins, G., Loureiro, A. P., Hamond, C., Pinna, M. H., Bremont, S., Bourphy, P., & Lilenbaum, W. (2014). First isolation of leptospira noguchii serogroups Panama and autumnalis from cattle. Epidemiology and Infection, 143(7), 1538–1541. https://doi.org/10.1017/s0950268814002416
[10] Stern, E. J., Galloway, R., Shadomy, S. V., Wannemuehler, K., Atrubin, D., Blackmore, C., Wofford, T., Wilkins, P. P., Ari, M. D., Harris, L., & Clark, T. A. (2010). Outbreak of leptospirosis among adventure race participants in Florida, 2005. Clinical Infectious Diseases, 50(6), 843–849. https://doi.org/10.1086/650578
[11] Zuerner, R. L. (2015). Leptospira. Bergey’s Manual of Systematics of Archaea and Bacteria, 1–19. https://doi.org/10.1002/9781118960608.gbm01244
[12] Gochenour WS Jr, Smadel JE, Jackson EB, Evans LB, Yager RH. Leptospiral etiology of Fort Bragg fever. Public Health Rep (1896). 1952 Aug;67(8):811-3. PMID: 12983521; PMCID: PMC2030907.
[13] Monroy, F. P., Solari, S., Lopez, J. Á., Agudelo-Flórez, P., & Peláez Sánchez, R. G. (2021). High diversity of Leptospira species infecting bats captured in the Uraba region (Antioquia-Colombia). Microorganisms, 9(9), 1897.
[14] Nieves, C., Vincent, A. T., Zarantonelli, L., Picardeau, M., Veyrier, F. J., & Buschiazzo, A. (2023). Horizontal transfer of the rfb cluster in Leptospira is a genetic determinant of serovar identity. Life Science Alliance, 6(2).
