In Silico Analysis of Usher Encoding Genes in Klebsiella pneumoniae and Characterization of Their Role in Adhesion and Colonization

Abstract

Chaperone/usher (CU) assembly pathway is used by a wide range of Enterobacteriaceae to assemble adhesive surface structures called pili or fimbriae that play a role in bacteria-host cell interactions. In silico analysis revealed that the genome of Klebsiella pneumoniae LM21 harbors eight chromosomal CU loci belonging to γκп and ϭ clusters. Of these, only two correspond to previously described operons, namely type 1 and type 3-encoding operons. Isogenic usher deletion mutants of K. pneumoniae LM21 were constructed for each locus and their role in adhesion to animal (Intestine 407) and plant (Arabidopsis thaliana) cells, biofilm formation and murine intestinal colonization was investigated. Type 3 pili usher deleted mutant was impaired in all assays, whereas type 1 pili usher deleted mutant only showed attenuation in adhesion to plant cells and in intestinal colonization. The LM21ΔkpjC mutant was impaired in its capacity to adhere to Arabidopsis cells and to colonize the murine intestine, either alone or in co-inoculation experiments. Deletion of LM21kpgC induced a significant decrease in biofilm formation, in adhesion to animal cells and in colonization of the mice intestine. The LM21∆kpaC and LM21∆kpeC mutants were only attenuated in biofilm formation and the adhesion abilities to Arabidopsis cells, respectively. No clear in vitro or in vivo effect was observed for LM21∆kpbC and LM21∆kpdC mutants. The multiplicity of CU loci in K. pneumoniae genome and their specific adhesion pattern probably reflect the ability of the bacteria to adhere to different substrates in its diverse ecological niches.

Diverse bacterial species contribute to antibiotic-associated diarrhoea and gastrointestinal damage

“…13 antimicrobial resistant K. pneumoniae strains were isolated from patients with AAD, DLL7526 (ST221, K39) and DLL7528 (ST1380, K31) (Figure 1), each encoding a range of virulence factors. This includes several types of fimbriae, which are known to facilitate biofilm formation and host cell adhesion (28,29); filamentous haemagglutinin; and putative autotransporter proteins ( Supplementary Table 8 and 9). K. pneumoniae has previously been isolated from AAD patients (30), as well as HIV-positive patients with a history of prolonged antimicrobial use and presenting with diarrhoea (31), however, its role in AAD has not previously been investigated.…”

An investigation into the Omp85 protein BamK in hypervirulent Klebsiella pneumoniae, and its role in outer membrane biogenesis

“…LPS display on the cell surface depends on the activity of the LptDE complex, which is assembled by the BAM complex. The type I and type III fimbrial adhesins are extended through usher proteins (Klemm & Schembri, , Wilksch et al, , Khater et al, ), which are themselves dependent on the BAM complex and the TAM for efficient assembly (Stubenrauch et al, , Stubenrauch et al, , Heinz et al, ). While the Wza secretion pore for capsular polysaccharide is not assembled by the BAM complex (Dunstan et al, ), the capsule has a key attachment factor Wzi that is a β‐barrel protein (Bushell et al, ).…”

“…The Wza capsule secretion pore appears to self‐assemble in the outer membrane (Dunstan et al, ), whereas most other outer membrane proteins are assembled by a highly sophisticated β‐barrel assembly machinery (BAM) composed of the core BAM complex (BAM ABCDE ) and the translocation and assembly module (the TAM) (Webb et al, , Plummer & Fleming, , Albenne & Ieva, , Noinaj et al, ). Each of these protein complexes is constituted around a membrane protein of the Omp85 protein family (BamA and TamA), and both are involved in the assembly of complex structures such as the adhesive fimbriae (Stubenrauch et al, , Stubenrauch et al, ) required by K. pneumoniae for biofilm formation (Klemm & Schembri, , Wilksch et al, , Khater et al, , Tan et al, ).…”

The Role of Pili Protein 38,6 kDa Klebsiella pneumoniae as a Hemagglutinin and Adhesin Protein which Serves as a Virulence Factor

“…Pili berperan dalam tahap awal perlekatan K. pneumonia pada permukaan sel inang. Hal ini karena pili mengandung protein yang dapat berikatan dengan molekul gula penyusun membran sel inang, yang disebut dengan protein hemaglutinin serta protein yang dapat berikatan dengan reseptor permukaan sel inang yang disebut dengan protein adhesin (Savage, 2003;Khater et al, 2015).…”