Why are pathogenic staphylococci so lysozyme resistant? The peptidoglycan <i>O</i>‐acetyltransferase OatA is the major determinant for lysozyme resistance of <i>Staphylococcus aureus</i>

TLDR

Staphylococcus species are among the few bacterial genera that are completely lysozyme resistant, enabling them to persist on skin and mucosal surfaces. The study aims to uncover the cause of lysozyme resistance in *Staphylococcus aureus*. The authors identified the oatA gene, encoding a peptidoglycan O‑acetyltransferase, as a key factor. Deletion of oatA increases lysozyme sensitivity, while complementation restores resistance, proving that oatA encodes the peptidoglycan O‑acetyltransferase responsible for staphylococcal lysozyme resistance.

Abstract

Summary Staphylococcus species belong to one of the few bacterial genera that are completely lysozyme resistant, which greatly contributes to their persistence and success in colonizing the skin and mucosal areas of humans and animals. In an attempt to discover the cause of lysozyme resistance, we identified a gene, oatA , in Staphylococcus aureus . The corresponding oatA deletion mutant had an increased sensitivity to lysozyme. HPLC and electrospray ionization tandem mass spectrometry analyses of the cell wall revealed that the muramic acid of peptidoglycan of the wild‐type strain was O‐acetylated at C6‐OH, whereas the muramic acid of the oatA mutant lacked this modification. The complemented oatA mutant was lysozyme resistant. We identified the first bacterial peptidoglycan‐specific O ‐acetyltransferase in S. aureus and showed that OatA, an integral membrane protein, is the molecular basis for the high lysozyme resistance in staphylococci.