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[Novel gene sequence variants of pbp2b in penicillin-nonsusceptible Streptococcus pneumonia isolates]

Su-Fei Tian1, Yun-Zhuo Chu, Bai-Yi Chen

  • 1Division of Infectious Diseases, The First Affiliated Hospital, China Medical University, Shenyang, China.

Zhonghua Nei Ke Za Zhi
|December 2, 2008
PubMed
Abstract

Insights

Penicillin-nonsusceptible Streptococcus pneumoniae (PNSP) showed common gene and amino acid alterations in penicillin-binding protein 2b (PBP2b). Novel variants were linked to intermediate resistance, suggesting PBP2b mutations are key to PNSP antibiotic resistance.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Context:

  • Streptococcus pneumoniae is a leading cause of bacterial infections worldwide.
  • The emergence of antibiotic resistance in S. pneumoniae poses a significant public health threat.
  • Penicillin-binding protein 2b (PBP2b) is a crucial target for penicillin antibiotics.

Purpose:

  • To investigate alterations in the gene and amino acid sequences of PBP2b in clinical isolates of penicillin-nonsusceptible S. pneumoniae (PNSP) from a specific region.
  • To identify specific mutations associated with varying levels of penicillin resistance.

Summary:

  • Twenty-four S. pneumoniae strains were analyzed for antibiotic susceptibility and pbp2b gene sequences.
  • Common PBP2b substitutions (Thr445Ala, Glu475Gly, Thr488Ser/Ala) were identified in PNSP isolates with minimal inhibitory concentrations (MICs) ≥0.1 mg/L.
  • Specific mutations, including Glu332Gly and Ala618Gly, were associated with higher resistance levels (MICs ≥0.25 mg/L and ≥3 mg/L, respectively).
  • Novel sequence variants were found in some resistant isolates, with sequences deposited in GenBank.

Impact:

  • Provides insights into the molecular mechanisms of penicillin resistance in S. pneumoniae.
  • Highlights the role of PBP2b sequence variations in determining antibiotic susceptibility.
  • Contributes to understanding the genetic basis of emerging antibiotic resistance patterns.

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