Soil Unknown: P. aeruginosa

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Classification

Domain Bacteria
Phylum Proteobacteria
Class Gammaproteobacteria
Order Pseudomonadales
Family Pseudomonadaceae
Genus Pseudomonas
Species Group Pseudomonas aeruginosa group
Species Pseudomonas aeruginosa

Species

NCBI: Taxonomy

Genus species: Pseudomonas aeruginosa

Habitat Information

The organism was isolated from 1 gram of a soil sample gathered from a park in the Barton Creek Landing complex in Travis County. In general, P. aeruginosa can be found in soil, decaying organic matter, and a variety of moist environments, including swimming pools, hot tubs, sponges, washcloths, and contact lens solutions (1).

Description and Significance

Describe the appearance (colonial and cellular), possible antimicrobial activity etc. of the organism, and why the organism might be significant.

Appearance

P. aeruginosa colonies appear to be of small to moderate, irregular, pulvinate and smooth. When incubated at 30 degrees celsius, the colonies have a small amount of orange pigmentation. When incubated at 37 degrees celsius, the colonies have gray pigmentation, as well as blue-green extracellular pigmentation:

30 degree incubation of Pseudomonas aeruginosa.
37 degree incubation of Pseudomonas aeruginosa.



Antimicrobial Activity

A study published in the Annals of Clinical Microbiology and Antimicrobials concluded that P. aeruginosa-derived extracellular compounds such as phenazines have inhibitory effects against MRSA. A synergic effect was observed when combined with silver nanoparticles produced by Fusarium oxysporum (2).

P. aeruginosa-derived phenazine and MRSA.


Strain PR3 of P. aeruginosa has been found to have antifungal properties, inhibiting both Candida albicans and rice blast fungus (3.)

Significance of organism

P.aeruginosa burn victim.jpg

Psuedomonas aeruginosa is a rare opportunist because it cannot penetrate the intact, natural defenses of the skin. Susceptible potential victims include burn victims, cancer patients, and immunocompromised patients. Those with cystic fibrosis have a higher risk of acquiring a P. aeruginosa lung infection.

P. aeruginosa is the most common microorganism seen in burn victims, and the microbe typically grows underneath the scab-like crust that naturally forms over a severe burn. Once established, it kills cells and destroys tissues. Large infections can be diagnosed due to the microbe's blue-green pyocyanin pigment. If P. aeruginosa invades the bloodstream, severe symptoms including fever, chills and shock can result

In general, a penicillin and an aminoglycoside are simultaneously used to treat P. aeruginosa infections. To treat a P. aeruginosa infection in a burn patient, debridement and administration of antimicrobial drugs are necessary.

Genome Structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Include S Ribosomal sequence that you obtained from PCR and sequencing here.


At 6.3 million base pairs, this is the largest bacterial genome sequenced.

S Ribosomal sequence: Group_2R-ACC_primer_-_reverse_D07.ab1 NNNNNNANNNNNNNCNNCCTGTNACTCTGTCCCCGAAGGGAAAGCCCTATCTCTAGGGTTGTCAGAGGATGTCAAGACCT GGTAAGGTTCTTCGCGTTGCTTCGAATTAAACCACATGCTCCACCGCTTGTGCGGGCCCCCGTCAATTCCTTTGAGTTTC AGTCTTGCGACCGTACTCCCCAGGCGGAGTGCTTAATGCGTTAGCTGCAGCACTAAGGGGCGGAAACCCCCTAACACTTA GCACTCATCGTTTACGGCGTGGACTACCAGGGTATCTAATCCTGTTCGCTCCCCACGCTTTCGCTCCTCAGCGTCAGTTA CAGACCAGAGAGTCGCCTTCGCCACTGGTGTTCCTCCACATCTCTACGCATTTCACCGCTACACGTGGAATTCCACTCTC CTCTTCTGCACTCAAGTTTCCCAGTTTCCAATGACCCTCCCCGGTTGAGCCGGGGGCTTTCACATCAGACTTAAGAAACC GCCTGCGAGCCCTTTACGCCCAATAATTCCGGACAACGCTTGCCACCTACGTATTACCGCGGCTGCTGGCACGTAGTTAG CCGTGGCTTTCTGGTTAGGTACCGTCAAGGTGCGAGCAGTTACTCTCGCACTTGTTCTTCCCTAACAACAGAGCTTTACG ATCCGAAAACCTTCATCACTCACGCGGCGTTGCTCCGTCAGACTTTCGTCCATTGCGGAAGATTCCCTACTGCTGCCTCC NNNNNNNNACTGNCCNNNNNNTTTNCNA


Cell Structure, Metabolism and Life Cycle

Interesting features of cell structure; how it gains energy; what important molecules it produces.


Gram Stain: Gram Negative Rods

P. aeruginosa is a Gram negative bacterium that is typically found in water and soil. Considered one of the top 3 opportunistic pathogens... It forms biofilms on rock

Physiology and Pathogenesis

Identifying biochemical characteristics and enzymes made

Gram Stain: Gram Negative Rods
Positive Motility Test
Negative Phenylalanine Deaminase Test
Positive Catalase Test
Negative MacConkey Agar Test
Negative Hektoen Enteric Agar Test
Weak Positive Eosin Methylene Blue Test. However, multiple other tests showed that lactose is not fermented by P. aeruginosa.



If relevant, how does this organism cause disease?

Hosts

  • Humans - those most susceptible include burn victims, cancer patients, and immunocompromised patients. Cystic fibrosis patients have a higher risk of lung infection.(1)
  • Animals - similar susceptibility patterns to humans. The most commonly colonized sites include wet or moist anatomic areas like the gut and respiratory tract, along with chronically wet areas of fur. (5)
  • Plants - certain strains are capable of infecting plant roots. A study published in Plant Physiology details two P.aeruginosa strains that infect the roots of Arabidopsis and sweet basil, and are capable of causing plant mortality. (6)


Virulence factors

  • Fimbriae and adhesions aid in attachment to host, as well as enabling biofilm formation.
  • Capsule helps shield the bacteria from phagocytosis, and also aids in bacterial attachment and biofilm formation.
  • Neuraminidase enzyme helps bacteria attach to host.
  • Elastase enzyme breaks down IgA, IgG, degrades complement components, and breaks down elastic fiber.
  • Lipid A component can trigger fever, blood clotting, inflammation, or shock.
  • Exotoxin A and exoenzyme S inhibit eukaryotic protein synthesis.
  • Pyocyanin pigment triggers the formation of reactive forms of oxygen, which damages host cells (1).


Patient Symptoms

  • Blue-green color where the bacterium is growing
  • With bacteremia: fever, blood clotting, inflammation and shock are possible
  • With lung infections: breathlessness, coughing, wheezing, rapid breathing, and weight loss (1)

References

1. Bauman, R. W. (2015) Microbiology with Diseases by Body System, pp. 567, 570. Glenview, IL: Pearson.
2. Cardozo, V., Oliveira, A.,Nishio, E. Antibacterial activity of extracellular compounds produced by a Pseudomonas strain against methicillin-resistant Staphylococcus aureus (MRSA) strains. Annals of Clinical Microbiology and Antimicrobials. 2013. Volume 12:12.
3. Bajpai, Vivek K.; Shin, Seung Yong; Kim, Hak Ryul; Kang, Sun Chul. 2008. Anti-fungal action of bioconverted eicosapentaenoic acid (bEPA) against plant pathogens. Industrial Crops and Products. 27(1): 136-141.
4. https://www.nature.com/articles/35023079
5. Psuedomonas aeruginosa Technical Sheet. Charles River Laboratories, 2017.
6.Walker, T., Bais, H., Deziel, E., and Schweizer, H., ''Pseudomonas aerutinosa-plant root interactions. Pathogenicity, biofilm formation, and root exudation. Plant Physiology'. 2004. Volume 134. p. 320 - 331.

[Sample reference] Takai, K., Sugai, A., Itoh, T., and Horikoshi, K. "Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney". International Journal of Systematic and Evolutionary Microbiology. 2000. Volume 50. p. 489-500.

Author

Page authored by Leila Adell and Katie Kelinske, students of Prof. Kristine Hollingsworth at Austin Community College.