A single mutation in enzyme I of the sugar phosphotransferase system confers penicillin tolerance to Streptococcus gordonii.
Tolerance is a poorly understood phenomenon that allows bacteria exposed to a bactericidal antibiotic to stop their growth and withstand drug-induced killing. This survival ability has been implicated in antibiotic treatment failures. Here, we describe a single nucleotide mutation (tol1) in a tolerant Streptococcus gordonii strain (Tol1) that is sufficient to provide tolerance in vitro and in vivo. It induces a proline-to-arginine substitution (P483R) in the homodimerization interface of enzyme I of the sugar phosphotransferase system, resulting in diminished sugar uptake. In vitro, the susceptible wild-type (WT) and Tol1 cultures lost 4.5 and 0.6 log(10) CFU/ml, respectively, after 24 h of penicillin exposure. The introduction of tol1 into the WT (WT P483R) conferred tolerance (a loss of 0.7 log(10) CFU/ml/24 h), whereas restitution of the parent sequence in Tol1 (Tol1 R483P) restored antibiotic susceptibility. Moreover, penicillin treatment of rats in an experimental model of endocarditis showed a complete inversion in the outcome, with a failure of therapy in rats infected with WT P483R and the complete disappearance of bacteria in animals infected with Tol1 R483P.
Department of Fundamental Microbiology, Faculty of Biology and Medicine, Biophore Building, University of Lausanne, Lausanne 1015, Switzerland. Alain.Bizzini@unil.ch
A
A
Bizzini
J M
JM
Entenza
O
O
Michielin
I
I
Arnold
B
B
Erni
P
P
Moreillon
D019943:Amino Acid Substitution; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D050260:Carbohydrate Metabolism / Q000187:drug effects; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D019281:Dimerization; D004696:Endocarditis / Q000382:microbiology; D004734:Energy Metabolism / Q000235:genetics / Q000502:physiology; D017353:Gene Deletion; D008040:Genetic Linkage / Q000235:genetics; D005947:Glucose / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D010403:Penicillin Resistance / Q000235:genetics*; D010406:Penicillins / Q000494:pharmacology; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics*; D017354:Point Mutation / Q000502:physiology*; D011487:Protein Conformation; D054773:Streptococcus gordonii / Q000187:drug effects* / Q000235:genetics*; D014170:Transformation, Genetic
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D010406:Penicillins; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; D005947:Glucose