Acanthamoeba and bacteria produce antimicrobials to target their counterpart

Junaid Iqbal, Ruqaiyyah Siddiqui, Naveed Ahmed Khan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Background
In the microbial ecosystem, microbes compete for space and nutrients. Consequently, some have developed the ability to kill or inhibit the growth of other competing microbes by producing antimicrobial substances. As the ‘producer’ species are generally immune to these substances, their compounds act on the competing microbial species and give the producer more space and access to nutrients for growth. Many currently used antibiotics were developed by exploiting this potential of certain microbes.

Findings
Here, the free-living amoeba, Acanthamoeba castellanii, was investigated for its antibacterial activity against representative Gram positive and Gram negative bacteria, while bacterial isolates were tested for their anti-amoebic properties. Conditioned medium from A. castellanii showed remarkable bactericidal properties against methicillin-resistant Staphylococcus aureus (MRSA) exhibiting almost 100% kill rate, but had limited effect against Acinetobacter sp., Pseudomonas aeruginosa and vancomycin-resistant Enterococcus faecalis (VRE). Similarly, the conditioned medium of E. coli K1 and Enterobacter sp., exhibited potent anti-Acanthamoebic effects in a concentration-dependent manner. Conditioned media of Acanthamoeba, E. coli K1 and Enterobacter sp. showed no cytotoxicity in vitro when tested against human brain microvascular endothelial cells. Active molecule/s in aforementioned amoebic and two bacterial conditioned media were 5 – 10 kDa, and <5 kDa respectively.

Conclusions
A. castellanii conditioned medium showed potent bactericidal properties against MRSA. The active molecule(s) are heat- and pronase-resistant, and in the 5 to 10 kDa molecular mass range. Contrary to this, E. coli K1 and Enterobacter sp., conditioned medium showed anti-amoebic effects that are <5 kDa in molecular mass, suggestive of active metabolites.
Original languageEnglish
Article number56
JournalParasites & Vectors
Volume7
DOIs
Publication statusPublished - 30 Jan 2014

Keywords

  • Conditioned Medium
  • Human Brain Microvascular Endothelial Cell
  • Acanthamoeba Castellanii
  • Acanthamoeba Trophozoite
  • Amoebicidal Activity

Fingerprint

Dive into the research topics of 'Acanthamoeba and bacteria produce antimicrobials to target their counterpart'. Together they form a unique fingerprint.

Cite this