Publications

4926

ABSTRACT “ Candidatus Neoehrlichia mikurensis” is the tick-borne agent of neoehrlichiosis, an infectious disease that primarily affects immunocompromised patients. So far, the genetic variability of “ Ca . Neoehrlichia” has been studied only by comparing 16S rRNA genes and groEL operon sequences. We describe the development and use of a multilocus sequence analysis (MLSA) protocol to characterize the genetic diversity of clinical “ Ca . Neoehrlichia” strains in Europe and their relatedness to other species within the Anaplasmataceae family. Six genes were selected: ftsZ , clpB , gatB , lipA , groEL , and 16S rRNA. Each MLSA locus was amplified by real-time PCR, and the PCR products were sequenced. Phylogenetic trees of MLSA locus relatedness were constructed from aligned sequences. Blood samples from 12 patients with confirmed “ Ca . Neoehrlichia” infection from Sweden ( n = 9), the Czech Republic ( n = 2), and Germany ( n = 1) were analyzed with the MLSA protocol. Three of the Swedish strains exhibited identical lipA sequences, while the lipA sequences of the strains from the other nine patients were identical to each other. One of the Czech strains had one differing nucleotide in the clpB sequence from the sequences of the other 11 strains. All 12 strains had identical sequences for the genes 16S rRNA, ftsZ , gatB , and groEL . According to the MLSA, among the Anaplasmataceae , “ Ca . Neoehrlichia” is most closely related to Ehrlichia ruminantium , less so to Anaplasma phagocytophilum , and least to Wolbachia endosymbionts. To conclude, three sequence types of infectious “ Ca . Neoehrlichia” were identified: one in the west of Sweden, one in the Czech Republic, and one spread throughout Europe.

Three novel isolates of the genus Bartonella were recovered from the blood of two patients enrolled in a clinical trial for the treatment of chronic stage Bartonella bacilliformis infection (verruga peruana) in Caraz, Ancash, Peru. The isolates were initially characterized by sequencing a fragment of the gltA gene, and found to be disparate from B. bacilliformis. The isolates were further characterized using phenotypic and genotypic methods, and found to be genetically identical to each other for the genes assessed, but distinct from any known species of the genus Bartonella, including the closest relative B. bacilliformis. Other characteristics of the isolates, including their morphology, microscopic and biochemical properties, and growth patterns, were consistent with members of the genus Bartonella. Based on these results, we conclude that these three isolates are members of a novel species of the genus Bartonella for which we propose the name Bartonella ancashensis sp. nov. (type strain 20.00T = ATCC BAA-2694T = DSM 29364T).

rinjal is an important vegetable crop grown worldwide. A field survey conducted during 2012 in Kerala state of South India, the little leaf disease affected brinjal plant was observed in one of the home gardens located at Nemmara (Palakkad district). The diseased and healthy samples were collected; genomic DNA was isolated and 16SrRNA gene amplified by performing nested PCR using universal primers pairs P1/P7 and R16F2n/R2 respectively. The association of Phytoplasma was detected in all the three symptomatic brinjal samples and in Phytoplasma affected Periwinkle used as positive control. An expected amplicon size of 1250bp from nested PCR was purified and sequenced. The nucleotide sequence analysis (nBLAST) of 1250bp fragment of sequence KL-50(KP027530) revealed 97% similarity with Candidatus phytoplasma trifolii (JX104336). Phylogenetic analysis and study of virtual RFLP gel pattern of the sequence also revealed the association of Candidatus phytoplasma trifolii.

ABSTRACT Symbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated with Melophagus ovinus , a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites. Interestingly, the whole system provides a remarkable analogy to the association between Glossina and its symbiotic bacteria. In both, the symbiotic systems are composed of an obligate symbiont and two facultative intracellular associates, Sodalis and Wolbachia . In addition, extracellular Bartonella resides in the gut of Melophagus . However, the phylogenetic origins of the two obligate mutualist symbionts differ. In Glossina , the mutualistic Wigglesworthia appears to be a relatively isolated symbiotic lineage, whereas in Melophagus , the obligate symbiont originated within the widely distributed Arsenophonus cluster. Although phylogenetically distant, the two obligate symbionts display several remarkably similar traits (e.g., transmission via the host's “milk glands” or similar pattern of genome reduction). To obtain better insight into the biology and possible role of the M. ovinus obligate symbiont, “ Candidatus Arsenophonus melophagi,” we performed several comparisons of its gene content based on assignments of the Cluster of Orthologous Genes (COG). Using this criterion, we show that within a set of 44 primary and secondary symbionts, “ Ca . Arsenophonus melophagi” is most similar to Wigglesworthia . On the other hand, these two bacteria also display interesting differences, such as absence of flagellar genes in Arsenophonus and their presence in Wigglesworthia . This finding implies that a flagellum is not essential for bacterial transmission via milk glands.

Abstract Xi.phi.ne.ma.to.bac'ter. Gr. neut. n. Xiphinema, ‐atos the genus name of the host organism; N.L. masc. n. bacter the equivalent of Gr. neut. n. baktron a rod; N.L. masc. n. Xiphinematobacter the rod‐shaped microbe associated with Xiphinema . Full‐grown cells are rod‐shaped with rounded ends, 0.7–1.0 × 2.1–3.2 μm ; however, cells in the J 1 (first juvenile) stage of nematode development have a wrinkled, pleomorphic shape. The longer entities usually consist of a mother cell from which a daughter cell is budding, giving rise to serial pairs typical of this bacterial genus. In thin sections cells have two or three membranes consisting of, from inside to outside, a cytoplasmic membrane, an electron‐dense outer membrane, and, in many individuals, a vacuolar membrane which is probably derived from the host cell membrane and which often shows discontinuities. No peptidoglycan layer is evident ; however, a periplasmic hexagonally arrayed monolayer of 10 nm protein units is sometimes present. Gram‐stain‐negative, nonmotile, and nonsporulating. DNA is often condensed at cell poles . Bacteria live as obligate cytoplasmic symbionts with maternal transmission in nematodes of the Xiphinema americanum group ( Nematoda, Longidoridae ), in which they are presumed to induce thelytokous ( mother‐to‐daughter ) parthenogenesis . DNA G + C content ( mol %): not determined. Type species : “ Candidatus Xiphinematobacter brevicolli ” Vandekerckhove, Willems, Gillis and Coomans 2000, 2203. Taxonomic and Nomenclature Notes According to the List of Prokaryotic names with Standing in Nomenclature (LPSN), the taxonomic status of the genus Candidatus Xiphinematobacter is: preferred name (not correct name) (last update, February 2025) * . LPSN classification: Bacteria / Pseudomonadati / Verrucomicrobiota / Terrimicrobiia / Terrimicrobiales / Chthoniobacteraceae / Candidatus Xiphinematobacter Candidatus Xiphinematobacter could not be recovered in GTDB ** . * Meier‐Kolthoff et al. ( 2022 ). Nucleic Acids Res , 50 , D801 – D807 ; DOI: 10.1093/nar/gkab902 ** Parks et al. ( 2022 ). Nucleic Acids Res , 50 , D785 – D794 ; DOI: 10.1093/nar/gkab776