Related Experiment Video

Updated: Aug 23, 2026

Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source
06:37

Staphylococcus aureus Growth using Human Hemoglobin as an Iron Source

Published on: February 7, 2013

Bacterial growth in amniotic fluid is dependent on the iron-availability and the activity of bacterial iron-uptake

Young-Joon Ahn1, Sang-Kee Park, Jae-Wook Oh

  • 1Department of Pediatrics, Seonam University Medical School, Namwon, Korea. shsin@chosun.ac.kr

Journal of Korean Medical Science
|June 18, 2004
PubMed

Insights

Meconium in amniotic fluid provides iron, stimulating bacterial growth by overcoming the fluid's natural antibacterial properties. Bacterial iron-uptake systems are crucial for growth in this environment.

Area of Science:

  • Microbiology
  • Biochemistry
  • Obstetrics

Background:

  • Amniotic fluid (AF) possesses antibacterial properties linked to iron availability.
  • Bacterial growth in AF is influenced by iron sources and bacterial iron-uptake systems (IUS).

Purpose of the Study:

  • To investigate the interplay between iron availability, antibacterial activity in AF, the role of meconium as an iron source, and bacterial IUS activity.
  • To determine how meconium affects bacterial growth and iron acquisition in AF.

Main Methods:

  • Utilized Staphylococcus aureus ATCC 6538 and a streptonigrin-resistant (SR) mutant with defective IUS.
  • Assessed bacterial growth in AF with varying concentrations of meconium, iron chelators, and iron sources.
  • Measured iron concentration in AF and correlated it with meconium content.
  • Examined the expression of high-affinity IUS in S. aureus under different conditions.

Main Results:

  • Meconium addition dose-dependently stimulated S. aureus growth in AF.
  • Stimulated growth was re-inhibited by iron chelators, indicating iron-dependency.
  • High-affinity IUS expression was observed in AF but not in AF with meconium.
  • The SR mutant showed more growth retardation than the parental strain in iron-deficient conditions, highlighting the importance of IUS.

Conclusions:

  • Antibacterial activity of AF is strongly correlated with low iron availability.
  • Bacterial growth in AF is significantly dependent on the functionality of bacterial IUS.
  • Meconium serves as an exogenous iron source, promoting bacterial proliferation in AF.

More Related Videos

Quantitating Iron Transport Across the Mouse Placenta In Vivo Using Nonradioactive Iron Isotopes08:45

Quantitating Iron Transport Across the Mouse Placenta In Vivo Using Nonradioactive Iron Isotopes

Published on: May 10, 2022

Metal-Limited Growth of Neisseria gonorrhoeae for Characterization of Metal-Responsive Genes and Metal Acquisition from Host Ligands07:26

Metal-Limited Growth of Neisseria gonorrhoeae for Characterization of Metal-Responsive Genes and Metal Acquisition from Host Ligands

Published on: March 4, 2020

Related Concept Videos

Microbes and Other Elemental Cycles01:24

Microbes and Other Elemental Cycles

Microbial activity plays a pivotal role in the biogeochemical cycling of iron and manganese, especially at the redox gradients characteristic of stratified aquatic environments. These cycles are driven by microbial transformations between oxidized and reduced forms of the metals, allowing organisms to exploit them for metabolic energy and structural purposes.Iron Cycling Across Redox GradientsIn neutral, oxygen-rich surface waters, iron is predominantly found in its oxidized, insoluble ferric...
Antimicrobial Proteins01:23

Antimicrobial Proteins

Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Development of Human Microbiota01:30

Development of Human Microbiota

The human microbiota begins developing at birth and undergoes continual change as we age. Infancy marks a critical period of microbial sensitivity, offering a “window of opportunity” during which beneficial microbes help mature the immune system. By age three, children typically develop a more stable and diverse microbial community. Newborns acquire microbes from their immediate environment; vaginal delivery favors maternal vaginal microbes, while cesarean births favor microbes from the skin...
Development of the Oral Microbiota01:28

Development of the Oral Microbiota

The establishment of the oral microbiome begins before birth, challenging the long-held belief that the fetal oral cavity is sterile. The presence of oral microbes such as Streptococcus and Fusobacterium in amniotic fluid suggests that microbial exposure may occur in utero, potentially through translocation from the maternal oral or gastrointestinal tract. This early colonization primes the neonatal immune system and sets the stage for subsequent microbial succession. Maternal health,...
Oxygen Requirements and Growth Patterns01:29

Oxygen Requirements and Growth Patterns

Microorganisms exhibit diverse oxygen requirements and growth patterns driven by their metabolic strategies and environmental adaptations. Oxygen, while essential for many organisms, can also be toxic under certain conditions, shaping how microorganisms grow and survive.Oxygen Requirements of MicroorganismsMicroorganisms are classified based on their ability to use or tolerate oxygen:● Obligate aerobes like Mycobacterium tuberculosis need oxygen for energy production, as it serves as the...
Microbial Nutrition01:28

Microbial Nutrition

Organisms exhibit remarkable metabolic diversity, categorized based on how they acquire energy and carbon. These strategies enable survival in various ecological niches and are essential for maintaining energy flow and nutrient cycling within ecosystems.Energy and Carbon SourcesOrganisms are classified as phototrophs or chemotrophs based on energy acquisition. Phototrophs use light as their energy source, while chemotrophs rely on oxidizing chemical compounds. Further differentiation arises...