Genetic analysis of pbp2x in clinical Streptococcus pneumoniae isolates in Quebec, Canada.
OBJECTIVE
To investigate the nature of the amino acid motifs found in penicillin-binding protein (PBP) 2x of penicillin-resistant Streptococcus pneumoniae isolates across the province of Quebec (Canada), and to obtain preliminary information regarding the prevalence of these alterations.


METHODS
The pbp2x genomic region encompassing codons 178-703, which includes the entire region of the transpeptidase domain, was sequenced and compared for 52 clinical isolates comprising 20 penicillin-susceptible (PSSP), 20 penicillin-intermediate (PISP) and 12 penicillin-resistant (PRSP) pneumococci.


RESULTS
The degree of diversity within PBP2x correlated with increased resistance to beta-lactam antibiotics. There were an average of 5.0 +/- 1.8 mutations in PSSP, 37.9 +/- 4.4 in PISP, and 63.0 +/- 2.0 in PRSP isolates when compared with the control penicillin-susceptible strain R6. At least six distinct amino acid profiles were identified among PISP strains isolated in Quebec. In contrast, all PRSP isolates shared a similar pattern of altered amino acids compared with the sequence from susceptible strains.


CONCLUSIONS
These data will be useful in future studies to monitor the genetic changes associated with the emergence and spread of beta-lactam resistance in Quebec.
Granger
Dominic
D
Laboratoire d'immunogénétique, Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, Canada.
Boily-Larouche
Geneviève
G
Turgeon
Pierre
P
Weiss
Karl
K
Roger
Michel
M
D000595:Amino Acid Sequence; D006801:Humans; D008969:Molecular Sequence Data; D046915:Penicillin-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000187:drug effects / Q000235:genetics*; D013329:Structure-Activity Relationship; D018440:beta-Lactam Resistance
D046915:Penicillin-Binding Proteins; C072223:PBP 2x protein, Streptococcus