title: Serious infections due to penicillin-resistant strains of viridans streptococci with altered penicillin-binding proteins.
abstract: We investigated the mechanism of resistance to penicillin in two penicillin-resistant clinical isolates of viridans streptococci that caused life-threatening infections in two patients not receiving chronic penicillin therapy. The first was a strain of Streptococcus intermedius that was isolated from the cerebrospinal fluid of a patient with post-neurosurgical meningitis. The second was a strain of Streptococcus mitis recovered from the bloodstream of a leukemic patient with neutropenia. Both patients failed to respond to penicillin. The mechanism of resistance in these strains was associated with diminished affinity for penicillin of their penicillin-binding proteins, as compared with those of penicillin-susceptible control strains. We conclude that penicillin-resistant viridans streptococci may cause serious infections even in patients not receiving chronic penicillin therapy, that this resistance is clinically significant and may result in failure of penicillin therapy, and that the mechanism of resistance in these strains is associated with diminished affinity of the penicillin-binding proteins for penicillin.
authors.affiliation: Department of Medicine, Michael Reese Hospital, Chicago, Illinois 60616.
authors.forename: J P
authors.initials: JP
authors.lastname: Quinn
authors.forename: C A
authors.initials: CA
authors.lastname: DiVincenzo
authors.forename: D A
authors.initials: DA
authors.lastname: Lucks
authors.forename: R L
authors.initials: RL
authors.lastname: Luskin
authors.forename: K L
authors.initials: KL
authors.lastname: Shatzer
authors.forename: S A
authors.initials: SA
authors.lastname: Lerner
mesh_terms: D000328:Adult; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D006602:Hexosyltransferases; D006801:Humans; D008297:Male; D008581:Meningitis / Q000382:microbiology; D008875:Middle Aged; D002267:Muramoylpentapeptide Carboxypeptidase / Q000502:physiology*; D010403:Penicillin Resistance; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D018805:Sepsis / Q000382:microbiology; D013290:Streptococcal Infections / Q000382:microbiology*; D013291:Streptococcus / Q000187:drug effects*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D046915:Penicillin-Binding Proteins; D010458:Peptidyl Transferases; D006602:Hexosyltransferases; D002267:Muramoylpentapeptide Carboxypeptidase