Helicobacter pylori Peptidoglycan Modifications Confer Lysozyme Resistance and Contribute to Survival in the Host

Journal Article · Tue Dec 04 00:00:00 EST 2012 · mBio (Online)

DOI:https://doi.org/10.1128/mbio.00409-12· OSTI ID:1626104

Wang, Ge ^[1]; Lo, Leja F. ^[2]; Forsberg, Lennart S. ^[3]; Maier, Robert J. ^[2]

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1. Univ. of Georgia, Athens, GA (United States). Dept. of Microbiology; DOE/OSTI
2. Univ. of Georgia, Athens, GA (United States). Dept. of Microbiology
3. Univ. of Georgia, Athens, GA (United States). The Complex Carbohydrate Research Center

The prominent host muramidase lysozyme cleaves bacterial peptidoglycan (PG), and the enzyme is abundant in mucosal secretions. The lytic enzyme susceptibility of Gram-negative bacteria and mechanisms they use to thwart lytic enzyme activity are poorly studied. We previously characterized a Helicobacter pylori PG modification enzyme, an N-deacetylase (PgdA) involved in lysozyme resistance. In this study, another PG modification enzyme, a putative PG O-acetyltransferase (PatA), was identified. Mass spectral analysis of the purified PG demonstrated that a patA strain contained a greatly reduced amount of acetylated muropeptides, indicating a role for PatA in H. pylori PG O-acetylation. The PG modification mutant strains (pgdA, patA, or pgdA patA) were more susceptible to lysozyme killing than the parent, but this assay required high lysozyme levels (up to 50 mg/ml). However, addition of host lactoferrin conferred lysozyme sensitivity to H. pylori, at physiologically relevant concentrations of both host components (3 mg/ml lactoferrin plus 0.3 mg/ml lysozyme). The pgdA patA double mutant strain was far more susceptible to lysozyme/lactoferrin killing than the parent. Peptidoglycan purified from a pgdA patA mutant was five times more sensitive to lysozyme than PG from the parent strain, while PG from both single mutants displayed intermediate sensitivity. Both sensitivity assays for whole cells and for purified PGs indicated that the modifications mediated by PgdA and PatA have a synergistic effect, conferring lysozyme tolerance. In a mouse infection model, significant colonization deficiency was observed for the double mutant at 3 weeks postinoculation. The results show that PG modifications affect the survival of a Gram-negative pathogen.

• Research Organization: Univ. of Georgia, Athens, GA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: FG02-93ER20097
• OSTI ID: 1626104
• Journal Information: mBio (Online), Journal Name: mBio (Online) Journal Issue: 6 Vol. 3; ISSN 2150-7511
• Publisher: American Society for Microbiology (ASM)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
Microbiology