Penicillin resistance in pneumococci is mediated by modified penicillin-bin
ding proteins (PBPs) that have decreased affinity to beta-lactams In high-l
evel penicillin-resistant transformants of the laboratory strain Streptococ
cus pneumoniae R6 containing various combinations of low-affinity PBPs, dis
ruption of the fib locus results in a collapse of PBP-mediated resistance.
In addition, crosslinked muropeptides are highly reduced. The fib operon co
nsists of two genes, fibA and fibB, homologous to Staphylococcus aureus fem
A/B which are also required for expression of methicillin resistance in thi
s organism. FibA and FibB belong to a family of proteins of Gram-positive b
acteria involved in the formation of interpeptide bridges, thus representin
g interesting new targets for antimicrobial compounds for this group of pat
hogens. (C) 2000 Federation of European Microbiological Societies. Publishe
d by Elsevier Science B.V. All rights reserved.