Impact of cell wall peptidoglycan O-acetylation on the pathogenesis of Staphylococcus aureus in septic arthritis.

Abstract

Staphylococcus aureus (S. aureus) is one of the most common pathogen causing septic arthritis. To colonize the joints and establish septic arthritis this bacterium needs to resist the host innate immune responses. Lysozyme secreted by neutrophils and macrophages is an important defense protein present in the joint synovial fluids. S. aureus is known to be resistant to lysozyme due to its peptidoglycan modification by O-acetylation of N-acetyl muramic acid. In this study we have investigated the role of O-acetylated peptidoglycan in septic arthritis. Using mouse models for both local and hematogenous S. aureus arthritis we compared the onset and progress of the disease induced by O-acetyl transferase mutant and the parenteral wild type SA113 strain. The disease progression was assessed by observing the clinical parameters including body weight, arthritis, and functionality of the affected limbs. Further X-ray and histopathological examinations were performed to monitor the synovitis and bone damage. In local S. aureus arthritis model, mice inoculated with the ΔoatA strain developed milder disease (in terms of knee swelling, motor and movement functionality) compared to mice inoculated with the wild type SA113 strain. X-ray and histopathological data revealed that ΔoatA infected mice knee joints had significantly lesser joint destruction, which was accompanied by reduced bacterial load in knee joints. Similarly, in hematogenous S. aureus arthritis model, ΔoatA mutant strain induced significantly less severe clinical septic arthritis compared to its parental strain, which is in accordance with radiological findings. Our data indicate that peptidoglycan O-acetylation plays an important role in S. aureus mediated septic arthritis.

• Authors: Gaurav Baranwal, Majd Mohammad, Anders Jarneborn, Bommana Raghunath Reddy, Archana Golla, Sumana Chakravarty, Lalitha Biswas, Friedrich Götz, Sahadev Shankarappa, Tao Jin, Raja Biswas
• Journal: International journal of medical microbiology : IJMM (Int J Med Microbiol) Vol. 307 Issue 7 Pg. 388-397 (Oct 2017) ISSN: 1618-0607 [Electronic] Germany
• PMID: 28802679 (Publication Type: Journal Article)
• Copyright: Copyright © 2017 Elsevier GmbH. All rights reserved.

Chemical References

• Muramic Acids
• Peptidoglycan
• N-acetylmuramic acid
• Acetyltransferases
• Muramidase

Topics

• Acetylation
• Acetyltransferases (genetics, metabolism)
• Animals
• Arthritis, Infectious (microbiology, physiopathology)
• Cell Wall (chemistry, metabolism)
• Disease Models, Animal
• Female
• Knee Joint (microbiology, pathology, physiopathology)
• Locomotion
• Mice
• Mice, Inbred BALB C
• Muramic Acids (metabolism)
• Muramidase (metabolism)
• Mutation
• Peptidoglycan (metabolism)
• Single-Blind Method
• Staphylococcal Infections (microbiology, physiopathology)
• Staphylococcus aureus (enzymology, genetics, physiology)