China
Africa
Explore chapters and articles related to this topic
Prognosis and Impact of Recurrent Uveitis, the Ophthalmic Infection Caused by Leptospira spp.
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
Charles Solomon Akino Mercy, Kalimuthusamy Natarajaseenivasan
The Spirochaetales are an order of bacteria dividing itself into two families: Spirochaetaceae and Leptospiraceae. The Spirochaetaceae family includes Treponema types, Serpulina and Borrelia, whereas the Leptospiraceae family includes Leptospira, which is further classified into Leptospira spp. are of importance because different serovars can exhibit different host specificities and may not be associated with a particular clinical form of infection. Classification of Leptospira is based on the expression of the surface exposed epitopes in a mosaic of the lipopolysaccharide (LPS) antigens, whereas the specificity of epitopes depends on their sugar composition and orientation (Dikken and Kmety 1978).
Syphilis
Published in Shiv Shanker Pareek, The Pictorial Atlas of Common Genito-Urinary Medicine, 2018
Syphilis is caused by a bacterium belonging to the Spirochaetaceae family. There are more than 70 species in the genera comprising this family, with some of the genus Treponema pathogenic to man, causing syphilis, yaws, bejel and pinta. Syphilis is caused by Treponema pallidum (Fig. 2.1), yaws is caused by Treponema pallidum pertenue (described by Castellani in 1905), Treponema pallidum carateum is responsible for pinta, while Treponema pallidum endemicum is the causative bacteria of bejel (non-venereal endemic syphilis).
Unique Pakistani gut microbiota highlights population-specific microbiota signatures of type 2 diabetes mellitus
Published in Gut Microbes, 2022
Afshan Saleem, Aamer Ikram, Evgenia Dikareva, Emilia Lahtinen, Dollwin Matharu, Anne-Maria Pajari, Willem M. de Vos, Fariha Hasan, Anne Salonen, Ching Jian
Our Pakistani cohort included 94 urban-dwelling adults living in and around the capital regions with and without confirmed T2D. Their gut microbiota was profiled using 16S rRNA gene amplicon sequencing targeting the V3-V4 region, which resulted in 17,160 ± 910 quality-controlled and chimera-checked reads per sample. Overall, Firmicutes and Actinobacteria were the most abundant phyla in the Pakistani population accounting for 63.7% and 25.2% of the total read counts on average, respectively, and they were observed in all the samples. Bacteroidetes and Proteobacteria constituted 5.3% and 4% of the total read counts, respectively, yet these microbes were found in 87% and 88% of the study participants, respectively. Verrucomicrobia (genus Akkermansia) made up less than 1% of the gut bacterial community and was detectable in only 16% of the individuals. Spirochetes (dominated by Spirochaetaceae/Treponema 2), a phylum observed mainly in ancient and non-industrialized societies but absent in industrialized populations,18 were detected in 10 Pakistani participants with an average abundance of 0.13%.
Links between environment, diet, and the hunter-gatherer microbiome
Published in Gut Microbes, 2019
Gabriela K. Fragiadakis, Samuel A. Smits, Erica D. Sonnenburg, William Van Treuren, Gregor Reid, Rob Knight, Alphaxard Manjurano, John Changalucha, Maria Gloria Dominguez-Bello, Jeff Leach, Justin L. Sonnenburg
With a sanitized water supply serving as a major characteristic of an industrialized society, we wondered whether the water sources available to the Hadza and other animals on the landscape may serve as an additional source of gut-colonizing microbes. We sampled water during the dry season from the surrounding area of the Hadza camps including streams, a well, and the dry riverbed. The samples varied in composition, but several had high levels of Prevotellaceae, one sample was 10% Spirochaetaceae, and several had low levels of Paraprevotellaceae (Figure 2C). When examining the same shared ASVs from the Hadza gut from the four VANISH families, nearly all were found in at least one water source (32/37 Prevotellaceae ASVs, 5/5 Spirochaetaceae ASVs, 7/8 Paraprevotellaceae ASVs, 2/3 Succinivibrionaceae ASVs). To address the possibility of contamination of water samples during sample preparation, we used an updated version of SourceTracker20 to compare the probabilistic contribution of fecal samples into water samples proximally located on the plate, relative to the contribution of randomly sampled proximally located fecal samples located on separate plates, and did not see any difference (p > 0.05, Wilcoxon test). While we are not equipped with sufficient data nor study design to explore the question of transmission, we found that Hadza gut bacteria that annually become undetectable and then re-appear are also present in the surrounding environment, offering the possibility that the Hadza gut is repopulated via environmental sources.
Laboratory diagnosis of Lyme borreliosis: Current state of the art and future perspectives
Published in Critical Reviews in Clinical Laboratory Sciences, 2018
Benedikt Lohr, Volker Fingerle, Douglas E. Norris, Klaus-Peter Hunfeld
Spirochetes that cause LB belong to the B. burgdorferi s.l. complex (Table 2); they are spiral-shaped bacteria of 4–30 µm in length and 0.2–0.3 µm in diameter (Figure 2) in the family Spirochaetaceae and belong to the genus Borrelia that comprises both the so-called relapsing fever borreliae, and the closely related LB agents. Relapsing fever borreliae are transmitted by lice (epidemic relapsing fever, B. recurrentis) and ticks (endemic tick-borne relapsing fever, B. caucasica, B. hispanica, B. hermsii, etc.). Tick-borne relapsing fever is endemic to certain regions around the world and is transmitted in Europe, particularly in Eastern and Southern Europe, by soft ticks belonging to Argasidae [19]. In contrast, epidemic relapsing fever caused by B. recurrentis is louse-borne and occurs worldwide [19–21]. Not long ago, another relapsing fever borrelia, B. miyamotoi, was described in Eurasia and North America. This relapsing fever borrelia is transmitted by the same ixodid ticks as LB agents and causes a mostly mild, flu-like illness, but it may also result in a more severe fever and in neurological disease, especially in immunosuppressed patients [22–25]. For the diagnosis of relapsing fever, detection of borreliae by microscopy, specific serological assays (using GlpQ protein as an antigen, especially for B. miyamotoi), and, when possible, molecular methods, is crucial [26]. The diagnosis of the relapsing fever borreliae is not reviewed here but is discussed in several recent publications on this topic [19,21,24]. A phylogenetic relationship of B. burgdorferi s.l. also exists to treponemes and leptospires that, due to possibly resulting cross-reactivity, can be relevant both for molecular and serological aspects of the laboratory diagnosis of LB [21,27–29].