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Penicillin-induced killing and postantibiotic effect in oral streptococci are enhanced by platelet microbicidal

Si Young Lee1, Son-Jin Choe

  • 1Department of Oral Microbiology, College of Dentistry, Research Institute of Oral Science, Kangnung National University, Kangnung 210-702, Republic of Korea. siyoung@knusun.kangnung.ac.kr

International Journal of Antimicrobial Agents
|May 4, 2004
PubMed

Insights

Thrombin-induced platelet microbicidal proteins (tPMP) and penicillin exhibit synergistic bactericidal effects against oral streptococci. Combining tPMP with penicillin enhances the postantibiotic effect, indicating cooperative antimicrobial action.

Area of Science:

  • Microbiology
  • Pharmacology
  • Hematology

Background:

  • Thrombin-induced platelet microbicidal proteins (tPMP) are cationic antimicrobial proteins from platelet alpha-granules.
  • tPMP demonstrates broad-spectrum microbicidal activity against pathogens relevant to infective endocarditis.

Purpose of the Study:

  • To investigate the in vitro synergistic interactions between tPMP and penicillin.
  • To evaluate the combined effects on both tPMP-susceptible and tPMP-insusceptible oral streptococci.

Main Methods:

  • Preparation of tPMP by stimulating rabbit platelets with thrombin.
  • In vitro testing of tPMP and penicillin alone and in combination against Streptococcus rattus BHT and Streptococcus gordonii DL1.
  • Assessment of synergistic bactericidal effects and postantibiotic effect duration.

Main Results:

  • tPMP and penicillin demonstrated a synergistic bactericidal effect against both S. rattus BHT and S. gordonii DL1.
  • Sequential exposure to tPMP followed by penicillin significantly extended the postantibiotic effect duration compared to penicillin alone.
  • These findings highlight cooperative antimicrobial activity.

Conclusions:

  • tPMP acts cooperatively with penicillin to enhance bactericidal and growth-inhibiting effects against oral streptococci.
  • The combination therapy shows potential for treating infections caused by these pathogens.

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