Mass Spectrometric Analysis of Bioactive Conditioned Media of Bacteria Isolated From Reptilian Gut

Abstract

Aim: To determine whether selected gut bacteria of crocodile exhibit antibacterial properties. Materials & methods: Two bacteria isolated from Crocodylus porosus gut were used, namely: Pseudomonas aeruginosa and Aeromonas dhakensis. Conditioned media were tested against pathogenic bacteria and metabolites were analyzed using liquid chromatography-mass spectrometry. Results & conclusion: Antibacterial assays revealed that conditioned media showed potent effects against pathogenic Gram-positive and Gram-negative bacteria. LC–MS revealed identity of 210 metabolites. The abundant metabolites were, N-Acetyl-L-tyrosine, Acetaminophen, Trans-Ferulic acid, N, N-Dimethylformamide, Pyrocatechol, Cyclohexanone, Diphenhydramine, Melatonin, Gamma–terpinene, Cysteamine, 3-phenoxypropionic acid, Indole-3-carbinol, Benzaldehyde, Benzocaine, 2-Aminobenzoic acid, 3-Methylindole. These findings suggest that crocodile gut bacteria are potential source of novel bioactive molecules that can be utilized as pre/post/antibiotics for the benefit of human health.

Plain Language Summary

Crocodiles thrive in unsanitary conditions, feed on rotten meat, and endure conditions that are detrimental to human health. In addition to their immune system, we speculate that their microbial gut flora produce substances contributing to their “hardiness” and “longevity”. Herein, we showed that selected bacteria isolated from crocodile gut produced potent antibacterial properties against multiple drug-resistant pathogenic Gram-negative and Gram-positive bacteria. LC–MS/MS revealed the identity of gut microbial metabolites. These findings suggest that analyses of crocodile gut bacteria may reveal potential drug leads that can be utilized as probiotics/pre/post/antibiotics for the benefit of human health, however intensive future research is needed to realize these expectations.

Tweetable abstract

Gut microbiome of hardy crocodile is a potential pharmacy that should be exploited for human benefit.

Graphical abstract

Keywords:

• antibiotic resistance
• gut microbiota
• metabolomics

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at:www.tandfonline.com/doi/full/10.2217/epi-2016-0184

Author contributions

R Siddiqui and N Ahmed Khan conceptualized the study. R Siddiqui and N Ahmed Khan received funding to carry out the research. R Siddiqui, SK Maciver, N Akbar and N Ahmed Khan designed and carried out experiments and analyzed data related to the antimicrobial part, while NC Soares, HM Al-Hroub and MH Semreen carried out analytical analysis using LC–MS/MS amid critical discussions with other researchers. R Siddiqui, NC Soares and N Ahmed Khan prepared the first draft of the manuscript. All authors reviewed and approved the final manuscript.

Financial & competing interests disclosure

This work was funded by the Ministry of Higher Education, Malaysia, grant no. FRGS/1/2018/SKK08/SYUC/01/2, and the Air Force Office of Scientific Research (AFOSR), grant no. FA 8655-20-1–7004. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations.