Major virulence factors of M. catarrhalis RH4a

RH4 locusGeneCommon name and general function of proteinCharacteristicsLevel of expression in growth phases in BHI mediumb
MCR_1198uspA1Ubiquitous surface protein A1; functions in adhesion to epithelial cells and ECM components, inhibition of NF-κB proinflammatory response via CEACAM binding, serum resistance, binding of complement regulatory proteins, and biofilm formation9 poly(G) repeats upstream of the ORF, reported to correlate with a low level of expressionc+++++++++
MCR_0329uspA2HUbiquitous surface protein A2H; functions in adhesion to epithelial cells, serum resistance, and biofilm formation+++++++++
MCR_0617mid/hagImmunoglobulin D binding protein/hemagglutinin; functions in adhesion to epithelial cells and IgD binding3 triplets of G residues at 5′ end within the ORF, reported to correlate with a high level of expressiond++++++++
MCR_0419mcaPM. catarrhalis adherence protein; functions in adhesion to epithelial cells+++++++++
MCR_1698ompCDOuter membrane protein CD; functions in adhesion to epithelial cells and middle ear mucinRFLP pattern 1 (∼200- and 100-nt BseJI restriction fragments), which is almost exclusively found in 16S type 1 isolatese+++++++++
MCR_0492copBOuter membrane protein CopB; involved in serum resistance and important for in vivo survivalRFLP type II (332- and 187-nt NsaI restriction fragments), which is found almost exclusively in 16S rRNA type I isolatese++++++++
MCR_0858ompEOuter membrane protein E; involved in serum resistancePutative homolog of long-chain fatty acid transporter FadL+++++++++
MCR_1591bro-2Beta-lactamase family protein BRO-2++++++
  • a Abbreviations: ECM, extracellular matrix; ORF, open reading frame; RFLP, restriction fragment length polymorphism; nt, nucleotides.

  • b ++, moderate; +++, high. See text.

  • c See reference 40.

  • d See reference 45.

  • e See reference 66.