What were the results of your 16S analysis?
Although I originally only got one PCR product for my L.5 isolate, I obtained two 16S RNA gene sequences from Prof. Salvo. Using BLAST, I was able to determine the identity of my two producers, P.1 and L.5. Both isolates were identified with very high confidence to belong to Pseudomonas genus (P.1: 980 base pairs, 100% query cover, 99% identity; L.5: 885 base pairs, 100% query cover, 99% identity).
Does your gram stain agree?
Unfortunately, because I only obtained a single PCR product, I just performed a Gram-stain on L.5 isolate but not on P.1 isolate. The Gram stain of L.5 producer allowed me to identify it as a Gram-negative rod-shaped bacterium, which is consistent for Pseudomonas as they are Gram-negative bacilli (1) (picture of my L.5 isolate’s Gram-stain can be found in my “Meet my Microbes!” blog post).
a) General cellular and morphological characteristics of the genus (taxonomic classification, nutrition, cell shape, habitat).
Pseudomonas are Gram-negative rod-shaped bacteria (1). They belong to Bacteria kingdom, Proteobacteria phylum, Gammaproteobacteria class, Pseudomonadales order, and Pseudomonadaceae family (2). This genus is found in soil, water, plants, and animals but is also known to inhabit in hospitals (1). Pseudomonas aeruginosa, a species of Pseudomonas, is known to have simple nutritional requirements as it can grow in just “distilled water” but can also withstand extreme physical conditions as it can grow in jet fuel or diesel (3). Additional information on the cellular and morphological characteristics of P. aeruginosa that belongs to this genus can be found in my “Meet the ESKAPE Pathogen” blog post.
b) Information regarding antibiotic production in this genus.
There are few cases of antibiotic-producing bacteria from the Pseudomonas genus:
One of them is mupirocin. It is an antibiotic that is used topically to treat skin infections. It is isolated from Pseudomonas fluorescens and has a broad spectrum activity against Gram-negative and Gram-positive bacteria (4). It works by inhibiting the bacterial isoleucyl-tRNA synthetase (5).
Another example of an antibiotic production is a bioactive organometallic compound that has shown to have an antibiotic ability against microorganisms; it can be isolated from Pseudomonas aeruginosa LV strain in the presence of copper chloride (6).
Lastly, isolated Pseudomonas viscosa shows broad antibiotic spectrum against a wide range of Gram-negative and Gram-positive bacteria that seems to have greater antibiotic ability relative to P. aeruginosa and P. fluorescens (7).
Works Cited
1. Iglewski, Barbara H. “Pseudomonas.” Current Neurology and Neuroscience Reports., U.S. National Library of Medicine, 1 Jan. 1996.
2.“Pseudomonas.” Encyclopedia of Life, eol.org/pages/83175/overview.
3. Putty, Murali. “Pseudomonas aeruginosa.” EMLab P&K, Mar. 2007
4. Matthijs, Sandra., et al. “Antimicrobial Properties of Pseudomonas Strains Producing the Antibiotic Mupirocin.” Research in Microbiology, 7 Oct. 2014.
5. Hughes, J, and G Mellows. “Inhibition of Isoleucyl-Transfer Ribonucleic Acid Synthetase in Escherichia coli by Pseudomonic Acid.” Current Neurology and Neuroscience Reports., U.S. National Library of Medicine, 15 Oct. 1978. Biochem J, 179 (1978), pp. 305-318.
6. Gionco Barbara., et al. “New Insights about Antibiotic Production by Pseudomonas aeruginosa: A Gene Expression Analysis.” Front Chem., 15 Sep. 2017.
7.Chinn, S. H. F. “An Antibiotic-Producing Bacterium of the Genus Pseudomonas.” Canadian Journal of Microbiology, 1973.
