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Molecular Analysis of PBP1A in Streptococcus pneumoniae Isolated from Clinical and Normal Flora Samples in Tehran,

Ali Ahmadi1, Sajad Yaghoubi2, GholamReza Irajian3,4

  • 11 Molecular Biology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences , Tehran, Iran .

Microbial Drug Resistance (Larchmont, N.Y.)
|August 3, 2018
PubMed

Insights

High-level penicillin resistance in pneumococcal isolates is linked to mutations in the pbp1a gene. These genetic changes reduce the bacteria

Area of Science:

  • Microbiology
  • Genetics
  • Infectious Diseases

Background:

  • High-level penicillin resistance in Streptococcus pneumoniae complicates treatment.
  • Understanding resistance mechanisms is crucial for effective therapies.

Purpose of the Study:

  • To investigate serotype, antimicrobial susceptibility, molecular typing, and pbp1a gene mutations in penicillin-resistant pneumococcal isolates from Tehran, Iran.
  • To analyze the genetic basis of high-level penicillin resistance in pneumococci.

Main Methods:

  • Polymerase chain reaction (PCR) amplification and sequencing of the pbp1a gene.
  • Antimicrobial susceptibility testing and molecular typing.
  • Genetic analysis of conserved motifs within the pbp1a gene.

Main Results:

  • The most common multidrug resistance pattern was 'E-CD-OX-TS-T' (18.0%).
  • Prevalent serotypes included 14 (21%), 19F (17%), 23F (16%), and 3 (16%).
  • Mutations were concentrated in the STMK conserved motifs, specifically at residues TSQF (574-577) NTGY, associated with reduced penicillin affinity.

Conclusions:

  • Multiple substitutions in the pbp1a gene are strongly associated with reduced affinity to penicillin in pneumococcal isolates.
  • This genetic alteration contributes to the emergence of high-level penicillin resistance and resistance to other beta-lactams.
Keywords:
IranPBP1a proteinPCRantibiotic resistance

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