Related Experiment Video

Updated: Oct 5, 2026

Stress-induced Antibiotic Susceptibility Testing on a Chip
12:41

Stress-induced Antibiotic Susceptibility Testing on a Chip

Published on: January 8, 2014

Ultrastructural alterations of bacteria during the postantibiotic effect

M Gottfredsson1, H Erlendsdóttir, R Kolka

  • 1Department of Clinical Microbiology, University of Iceland Medical School, Borgarspitalinn, Reykjavik.

Chemotherapy
|May 1, 1993
PubMed

Insights

Microscopic examination revealed that antibiotics cause distinct ultrastructural changes in Staphylococcus aureus and Pseudomonas aeruginosa during their postantibiotic effect (PAE). These bacterial cell alterations correlate with the PAE duration, offering insights into antibiotic activity.

Area of Science:

  • Microbiology
  • Cell Biology
  • Pharmacology

Background:

  • The postantibiotic effect (PAE) is a crucial parameter in antibacterial therapy, representing the period of growth inhibition after antibiotic exposure.
  • Understanding the morphological changes bacteria undergo during PAE can provide insights into mechanisms of action and resistance.

Purpose of the Study:

  • To investigate the ultrastructural alterations in Staphylococcus aureus and Pseudomonas aeruginosa during the postantibiotic effect (PAE) following exposure to various antibiotics.
  • To correlate observed morphological changes with the duration of the PAE.

Main Methods:

  • Transmission electron microscopy (TEM) was employed to visualize ultrastructural changes in bacterial cells.
  • Bacterial viability was assessed using viable counts to determine the duration of the PAE.

Main Results:

  • Staphylococcus aureus exposed to dicloxacillin showed increased crosswall formation, while rifampin induced cell wall thickening. Gentamicin caused minimal changes.
  • Pseudomonas aeruginosa exhibited intracellular electrondense aggregates after exposure to imipenem, tobramycin, and ciprofloxacin. Imipenem also induced globoid cell formations.
  • Observed ultrastructural alterations varied among individual organisms but consistently correlated with the determined PAE duration.

Conclusions:

  • Antibiotic exposure induces specific and observable ultrastructural changes in bacteria during the PAE.
  • These morphological changes are linked to the duration of the PAE, providing a visual correlate to bacterial growth inhibition.

More Related Videos

A Protocol to Characterize the Morphological Changes of Clostridium difficile in Response to Antibiotic Treatment12:58

A Protocol to Characterize the Morphological Changes of Clostridium difficile in Response to Antibiotic Treatment

Published on: May 25, 2017

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes07:44

Time-Lapse Epifluorescence Microscopy Imaging of Pseudomonas aeruginosa and Staphylococcus aureus Heterogeneous Phenotypes

Published on: February 14, 2025

Related Concept Videos

Development of Antibiotic Resistance01:30

Development of Antibiotic Resistance

Antibiotic resistance is a major public health concern that arises when bacteria evolve mechanisms to withstand the effects of antibiotic treatments. This resistance can be intrinsic, acquired through genetic mutations, or transferred between bacteria via horizontal gene transfer. The development of antibiotic resistance poses significant challenges in treating bacterial infections and necessitates ongoing research to develop new therapeutic strategies.Intrinsic resistance occurs when bacterial...
Microbiota Modulation by Antibiotics01:21

Microbiota Modulation by Antibiotics

Antibiotics have revolutionized modern medicine by saving countless lives from bacterial infections. However, their widespread use has inadvertently harmed the delicate balance of the human gut microbiota. The gut microbiota, a complex community of bacteria, archaea, viruses, and fungi, plays a vital role in regulating metabolism, immune responses, and maintaining intestinal health. Antibiotics, especially broad-spectrum types, disrupt this ecosystem by eradicating both harmful and beneficial...
Mechanism of Antibiotic Resistance in MRSA01:25

Mechanism of Antibiotic Resistance in MRSA

Antibiotic resistance in bacteria arises when microorganisms evolve the ability to withstand drugs designed to kill them or inhibit their growth, rendering once-effective treatments useless. This phenomenon, driven by genetic change and selection under antibiotic exposure, poses a profound threat to modern medicine. Mechanisms include drug-inactivating enzymes (e.g., β-lactamases), efflux pumps that eject antibiotics, mutations altering antibiotic targets, decreased drug uptake, and acquisition...
Inhibitors of Gram-positive Cell Wall Synthesis01:23

Inhibitors of Gram-positive Cell Wall Synthesis

Bacterial cell walls are typically rigid structures composed mainly of peptidoglycan, a mesh-like polymer that provides mechanical strength and maintains cell shape. The synthesis of peptidoglycan is a crucial process in bacterial growth and serves as a primary target for many antibiotics.Mechanism of Action of Beta-Lactam AntibioticsBeta-lactam antibiotics, such as penicillin, inhibit peptidoglycan synthesis in actively growing cells. These antibiotics share a characteristic four-membered...
Inhibitors of Bacterial Protein Synthesis01:25

Inhibitors of Bacterial Protein Synthesis

Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
Clinical Significance of Antibiotic Resistance01:25

Clinical Significance of Antibiotic Resistance

Methicillin-resistant Staphylococcus aureus (MRSA) presents a critical public health threat, arising from its capacity to resist β-lactam antibiotics due to acquisition of the mecA gene within the staphylococcal cassette chromosome mec (SCCmec). This gene encodes penicillin-binding protein 2a (PBP2a), which impairs binding efficacy of methicillin and other β-lactams. MRSA has evolved into distinct clonal lineages impacting humans and animals alike, reinforcing its significance within the One...