Penicillin-binding proteins (PBPs) of Streptococcus faecalis NCTC 775, S. faecium NCTC 7171 and an isolate of S. faecium (strain 37) highly resistant to β-lactam antibiotics were visualised by autoradiography. Five PBPs were detected in S. faecalis NCTC 775 and six in S. faecium NCTC 7171. Additional PBPs could not be found in the resistant isolate of S. faecium.
The PBP affinities of β lactams were compared with MIC values. The affinities of PBPs 3 and 4 of S. faecalis NCTC 775 for penicillin G, ampicillin, cefathiamidine, cephaloridine and cephazolin were related to the sensitivity of the strain to these antibiotics as were the affinities of PBPs 4 and 5 in each S. faecium strain for the β lactams. It is postulated that PBPs 3 and 4 of S. faecalis NCTC 775 and PBPs 4 and 5 of S. faecium are the relevant target enzymes of the test antibiotics. PBPs 4 and 5 of the highly β-lactam-resistant S. faecium strain 37 showed proportionally low affinities for the five β lactams compared to that of the less resistant strain S. faecium NCTC 7171. Decreased affinities of PBPs 4 and 5 may account for the resistance in S. faecium strain 37 to β lactams. The affinities for PBP 1, 2 and 5 in S. faecalis NCTC 775 and PBPs 1, 2, 3 and 6 in S. faecium were not related to the antibiotic sensitivities.
BlumbergP. M.,
StromingerJ. L.1974; Interaction of penicillin with the bacterial cell: 3 penicillin-binding proteins and penicillin-sensitive enzymes. Bacteriological Reviews 38:291–35
BoultonM. G.,
OrrD. C.1983; Detection of bacterial penicillinbinding proteins and their role in the interpretation of the role of action of beta-lactam antibiotics. In
RussellA. D.,
QuesnalL. B.
(eds) Antibiotics: assessment of antimicrobial activity and resistance. Academic Press; London: pp 161–182
ChenH. Y.,
WilliamsJ. D.1983; The killing effects of cefathiamidine or ampicillin alone and in combination with gentamicin against enterococci. Journal of Antimicrobial Chemotherapy 12:19–26
EliopoulosG. M.,
WennerstenC.,
MoelleringR. C.1982; Resistance to beta-lactam antibiotics in Streptococcus faecium. Antimicrobial Agents and Chemotherapy 22:295–301
FontanaR.,
CeriniR.,
LongoniP.,
GrossatoA.,
CanepariP.1983; Identification of a streptococcal penicillin-binding protein that reacts very slowly with penicillin. Journal of Bacteriology 155:1343–1350
FontanaR.,
GrossatoA.,
RossiL.,
ChengY. R.,
SattaG.1985; Transmission from resistance to hypersusceptibility to beta- lactam antibiotics associated with loss of a low-affinity penicillin-binding protein in a Streptococcus faecium mutant highly resistant to penicillin. Antimicrobial Agents and Chemotherapy 28:678–683
GeorgopapadakouN. H.,
LiuF. Y.1980b; Binding of beta-lactam antibiotics to penicillin-binding proteins of Staphylococcus aureus and Streptococcus faecalis: relation to antibacterial activity. Antimicrobial Agents and Chemotherapy 18:834–836
HakenbeckR.,
TarpayM.,
TomaszA.1980; Multiple changes of penicillin-binding proteins in penicillin-resistant clinical isolates of Streptococcus pneumoniae. Antimicrobial Agents and Chemotherapy 17:364–371
HayesM. V.,
CurtisN. A. C.,
WykeA. W.,
WardJ. B.1981; Decreased affinity of a penicillin-binding protein for beta-lactam antibiotics in a clinical isolate of Staphylococcus aureus resistant to methicillin. FEMS Microbiology letters 10:119–122
HuffE.,
OxleyH.,
SilvermanC. S.1964; Density-gradient patterns of Staphylococcus aureus cells and cell walls during growth and mechanical disruption. Journal of Bacteriology 88:1155–1162
MatthewM.,
HarrisA. M.1976; Identification of beta-lactamases by analytical isoelectric focusing: correlation with bacterial taxonomy. Journal of General Microbiology 94:55–67
MurrayB. E.,
Mederski-SamarojB.1983; xTransferable beta- lactamase. A new mechanism for in-vitro penicillin resistance in Streptococcus faecalis. Journal of Clinical Investigation 72:1168–1171
NikaidoH.1981; Outer membrane permeability of bacteria: resistance and accessibility of targets. In
SaltonM. R. J.,
ShockmanG. D.
(eds) Beta-lactam antibiotics: mode of action, new developments and future prospects. Academic Press; New York: pp 249–260
StromingerJ. L.,
WilloughbyE.,
KamiryoT.,
BlumbergP. M.,
YocumR. R.1974; Penicillin-sensitive enzymes and penicillin-binding components in bacterial cells. Annals of the New York Academy of Sciences 235:210–224
UbukataK.,
YamashitaN.,
KonnoM.1985; Occurrence of a beta- lactam-inducible penicillin-binding protein in methicillin- resistant Staphylococci. Antimicrobial Agents and Chemotherapy 27:851–857
WilliamsonR.,
CalderwoodS. B.,
MoelleringR. C.,
TomaszA.1983; Studies on the mechanism of intrinsic resistance to beta-lactam antibiotics in Group D streptococci. Journal of General Microbiology 129:813–822
WykeA. W.,
WardJ. B.,
HayesM. V.1982; Synthesis of peptidoglycan in vivo in methicillin-resistant Staphylococcus aureus. European Journal of Biochemistry 127:553–558
ZighelboimS.,
TomaszA.1980; Penicillin-binding proteins of multiply antibiotic-resistant South African strains of Streptococcus pneumoniae. Antimicrobial Agents and Chemotherapy 17:434–442