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Morphological and Bactericidal Effects of Amikacin, Meropenem and Imipenem on Pseudomonas aeruginosa

Mohsen Moghoofei1, Hossein Fazeli1, Farkhondeh Poursina1

  • 1Department of Microbiology, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, IR Iran.

Jundishapur Journal of Microbiology
|February 9, 2016
PubMed
Abstract

Insights

Antibiotic stress transforms Pseudomonas aeruginosa into coccoid forms, increasing drug resistance and treatment failure. Careful antibiotic dosing is crucial to prevent this resistance and coccoid bacteria induction.

Area of Science:

  • Microbiology
  • Pharmacology
  • Infectious Diseases

Background:

  • Antibiotic treatment can induce morphological changes in Pseudomonas aeruginosa, potentially leading to increased antibiotic resistance.
  • The conversion of P. aeruginosa to coccoid bacteria under antibiotic stress is linked to cell wall alterations and reduced metabolic activity, contributing to treatment failure.

Purpose of the Study:

  • To investigate the in vitro morphological and bactericidal effects of amikacin, meropenem, and imipenem on clinical isolates of Pseudomonas aeruginosa.

Main Methods:

  • Utilized eight P. aeruginosa clinical isolates and a standard strain, identified via biochemical tests and PCR.
  • Determined Minimum Inhibitory Concentrations (MICs) using E-test and exposed bacteria to antibiotics at various concentrations.
  • Monitored bacterial morphology using microscopy and assessed viability via flow cytometry over several days.

Main Results:

  • Sub-MIC concentrations of amikacin, meropenem, and imipenem induced coccoid bacterial forms in P. aeruginosa.
  • Imipenem and meropenem at 2 μg/mL induced the highest rate of coccoid bacteria (98.2%) after 8 days.
  • Amikacin showed a dose-dependent induction of coccoid forms (55.05% at 4 μg/mL) and a strong bactericidal effect at 8 μg/mL, unlike imipenem and meropenem which had weak bactericidal effects on coccoid forms.

Conclusions:

  • The induction of P. aeruginosa coccoid forms by antibiotics is a significant factor in treatment failure.
  • Judicious management of antibiotic dosage is essential to mitigate the rise of antibiotic resistance and prevent coccoid bacteria induction.
Keywords:
Coccoid BacteriaDrug ResistancePseudomonas aeruginosa

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