Correlation of teichoic acid D-alanyl esterification with the expression of methicillin resistance in Staphylococcus aureus
O'Brien, M.J.; Kuhl, S.A.; Starzyk, M.J.
Microbios 83(335): 119-137
1995
ISSN/ISBN: 0026-2633 PMID: 8538492 Document Number: 442268
Methicillin-susceptible and -resistant isolates of Staphylococcus aureus, including a teichoic acid-deficient mutant, were examined under varying physiological conditions for their degree of teichoic acid and lipoteichoic acid D-alanyl esterification. Methicillinresistant strains grown in the presence of methicillin and NaCl possessed significantly decreased amounts of D-alanyl ester when compared with methicillin-susceptible isolates. These strains also exhibited reduced autolysis. An autoradiographic procedure was used to detect mutants, isolated by Tn9l7 and nitrosoguanidine mutagenesis of methicillin- susceptible strains, which were defective in D-alanyl ester formation. The quantitative uptake of D-(14C)alanine in these mutants was determined and the off act of methicillin on the growth and viability of each mutant was compared with the wild-type strain. S. aureus mutant strains, defective in the uptake and incorporation of D-alanine, were shown to exhibit slightly reduced autolysis and an enhanced expression of methicillin resistance.