A. Severin et al., ABNORMAL PHYSIOLOGICAL-PROPERTIES AND ALTERED CELL-WALL COMPOSITION IN STREPTOCOCCUS-PNEUMONIAE GROWN IN THE PRESENCE OF CLAVULANIC ACID, Antimicrobial agents and chemotherapy, 41(3), 1997, pp. 504-510
Subinhibitory concentrations of clavulanate caused premature induction
of stationary-phase autolysis, sensitization to lysozyme, and reducti
ons in the MICs of deoxycholate and penicillin for Streptococcus pneum
oniae. In the range of clavulanate concentrations producing these effe
cts, this beta-lactam compound was selectively bound to PBP 3. Cell wa
lls isolated from pneumococci grown in the presence of clavulanate sho
wed increased sensitivity to the hydrolytic action of purified pneumoc
occal autolysin in vitro. High-performance liquid chromatography analy
sis of the peptidoglycan isolated from the clavulanate-grown cells sho
wed major qualitative and quantitative changes in stem peptide composi
tion, the most striking feature of which was the accumulation of pepti
de species carrying intact D-alanyl-D-alanine residues at the carboxy
termini, The altered biological and biochemical properties of the clav
ulanate-grown pneumococci appear to be the consequences of suppressed
D,D-carboxypeptidase activity.