Molecular characterization of newly identified Klebsiella PKBSG14 and analysis of its effect on immune response and cell cycle progression using common catfish (Channa punctatus) as a model

• Published in: Microbial pathogenesis 2019-02, Vol.127, p.368-379
• Main Authors: Ghosh, Subarna, Bandyopadhyay, P.K.
• Format: Article
• Language: English
• Subjects: Cellcycle; Innate immunity; Klebsiella PKBSG14; rmpA; Splenic macrophages; wcaG
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2018.12.026

Microbial studies on Catfish revealed that Klebsiella is the most common pathogen causing prevalence of ulcers, fin erosion, and other lesions. During this study, a new strain of bacteria was isolated from Channa punctatus, and molecular identification by 16srRNA revealed the strain was Klebsiella PKBSG14 (Accession no KJ162158). The strain was also PCR positive for two virulent gene wcaG (Accession no LN606595) and rmpA (Accession no LN606594) responsible for inflammatory reactions and induction of innate immune response in the host cell. To study innate immune response induced by pathogenic infection the phagocytic interactive process between the spleen macrophages and KlebsiellaPKBSG14 was investigated using optical microscopy. FACS of splenic macrophages revealed that the phagocytic interaction leads to the process of macrophage cell cycle progression. A detailed study on the macrophage DNA content by performing DNA fragmentation and comet allowed us to study simultaneously host cell division as a function of phagocytosis and the findings unveiled the fact that Phagocytosis of KlebsiellaPKBSG14 aided in macrophage cell cycle progression but was less likely to complete mitosis. Here we also report the cytotoxic effect linked to the infection with KlebsiellaPKBSG14 by performing Cell viability assay, intracellular production of ROS, and mitochondrial transmembrane potential where it manifested itself in impaired cellular function. So, in summary, we simultaneously discovered a new strain of bacteria ie. Klebsiella PKBSG14 as well as deliberately attempted to study the immunomodulatory effect of isolated new stain on Channa punctatus by performing host-pathogen phagocytic interactive experiments, the cell cycle state of the host cell and pathogen-mediated cytotoxicity along with genotoxicity, and our results evidence a new immunomodulatory effect of KlebsiellaPKBSG14 infection on fish splenic macrophages. [Display omitted] •KlebsiellaPKBSG14 identified using 16srRNA and electron microscopy.•The strain positive for rmpA and wcaG.•Innate immune response between host and Klebsiella PKBSG14 studied.•Effects of Klebsiella PKBSG14 at cellular level executed.•Comet, DNA fragmentation conducted.