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.
Bizzini
A
A
Department of Fundamental Microbiology, Faculty of Biology and Medicine, Biophore Building, University of Lausanne, Lausanne 1015, Switzerland. Alain.Bizzini@unil.ch
Entenza
J M
JM
Michielin
O
O
Arnold
I
I
Erni
B
B
Moreillon
P
P
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