Affiliation:
1. Laboratory of Microbiology, The Rockefeller University, New York, New York 10021
2. Department of Microbiology, Tianjin Medical University, Tianjin, People's Republic of China
Abstract
ABSTRACT
A close homologue of the acquired
Staphylococcus aureus mecA
gene is present as a native gene in
Staphylococcus sciuri
. We determined the patterns of penicillin-binding proteins (PBPs) and the peptidoglycan compositions of several
S. sciuri
strains to explore the functions of this
mecA
homologue, named
pbpD
, in its native
S. sciuri
environment. The protein product of
pbpD
was identified as PBP4 with a molecular mass of 84 kDa, one of the six PBPs present in representatives of each of three subspecies of
S. sciuri
examined. PBP4 had a low affinity for nafcillin, reacted with a monoclonal antibody raised against
S. aureus
PBP2A, and was greatly overproduced in oxacillin-resistant clinical isolate
S. sciuri
SS37 and to a lesser extent in resistant laboratory mutant K1M200. An additional PBP inducible by oxacillin and corresponding to
S. aureus
PBP2A was identified in another oxacillin-resistant clinical isolate,
S. sciuri
K3, which harbors an
S. aureus
copy of
mecA
. Oxacillin resistance depended on the overtranscribed
S. sciuri pbpD
gene in strains SS37 and K1M200, while the resistance of strain K3 depended on the
S. aureus
copy of
mecA
. Our data provide evidence that both
S. aureus mecA
and
S. sciuri pbpD
can function as resistance determinants in either an
S. aureus
or an
S. sciuri
background and that the protein products of these genes,
S. aureus
PBP2A and
S. sciuri
PBP4, can participate in the biosynthesis of peptidoglycan, the muropeptide composition of which depends on the bacterium “hosting” the resistance gene.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
28 articles.
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