The main mechanism of resistance of pneumococci to penicillin is the alteration of the affinities of penicillin binding proteins (PBPs) to -lactams by heterologous recombination events (4). For the present study, we have investigated the diversity of the penA (accession numbers AM779386 to AM779409), pbpX (AM779338 to AM779361), and pbp1A (AM779362 to AM779385) genes of 21 clinical Portuguese S...

We analyzed seven Streptococcus pneumoniae serogroup 35 isolates by pulsed-field gel electrophoresis of the genome and pbp2b gene nucleotide sequences. Three penicillin-susceptible strains and one penicillin-intermediate-resistant strain exhibited 100% identity to prototype R6. Two resistant strains and one other intermediate strain differed from them and contained a unique sequence.

The antibiotic susceptibilities, genotypes of penicillin (PEN)-binding protein genes (pbp), and serotype distributions of Streptococcus pneumoniae isolates from meningitis patients were investigated by a nationwide surveillance group in Japan between 1999 and 2002. We analyzed 146 isolates from children (/=18 years old). Isolates with or without abnormal pb...

The in vitro activity of tebipenem (TBM), a new oral carbapenem antibiotic, against Streptococcus pneumoniae clinical isolates (n = 202) was compared with those of 15 reference agents. The isolates were classified into five genotypic classes after PCR identification of abnormal pbp1a, pbp2x, and pbp2b genes: (i) penicillin-susceptible S. pneumoniae (PSSP) isolates with no abnormal pbp genes (n ...

High-level resistance to beta-lactam antibiotics in Streptococcus pneumoniae is mediated by successive alterations in essential penicillin-binding proteins (PBPs). In the present work, single amino acid changes in S. pneumoniae PBP 2x and PBP 2b that result in reduced affinity for the antibiotic and that confer first-level beta-lactam resistance are defined. Point mutations in the PBP genes wer...

introduction : streptococcus pneumoniae cause morbidity and mortality in infants and younger children. because of high prevalence of penicillin resistance, rapid and reliable diagnostic techniques for penicillin non-susceptible s. pneumoniae (pnssp) are important for prevention and treatment. we investigated the association of the restriction length polymorphism (rflp) patterns for pbp2b to dis...

results the number of s. pneumoniae isolates resistant to benzylpenicillin, imipenem, oxacillin and ceftazidime were 94.5%, 100%, 100%, and 21.8%, respectively. analysis of mutation in the genes for pbp showed that 85% of isolates had mutations in pbp2x, pbp2b and pbp1a. susceptibility to benzylpenicillin was decreased once the number of mutated pbp genes in s. pneumonia increased. according to...

Heteroresistance to penicillin in Streptococcus pneumoniae is the ability of subpopulations to grow at a higher antibiotic concentration than expected from the MIC. This may render conventional resistance testing unreliable and lead to therapeutic failure. We investigated the role of the primary β-lactam resistance determinants, penicillin-binding protein 2b (PBP2b) and PBP2x, and the secondary...

The prevalence of antibiotic resistance genes in pathogenic bacteria is a major challenge to treating many infectious diseases. The spread of these genes is driven by the strong selection imposed by the use of antibacterial drugs. However, in the absence of drug selection, antibiotic resistance genes impose a fitness cost, which can be ameliorated by compensatory mutations. In Streptococcus pne...

BACKGROUND β-lactams resistant Streptococcus pneumoniae are an emerging problem throughout the world. Several resistance mechanisms have been reported, including expression of drug-destroying enzymes such as β-lactamases, altered drug targets such as conformational changes in PBPs, decreased bacterial permeability, and increased drug efflux. OBJECTIVES The present study aimed to determine the...