Diego's microbe wiki
Classification
'Kingdom': Bacteria
Phylum': Proteobacteria
'Class': Gamaproteobacteria
Order': Eubacteriales
Family': Enterobacteriaceae
Species
'Genus':Enterobacter;
'Species':Cloacae
the suffix "Enteric" signifies a microorganism pertaining to or originating from the intestines.
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NCBI: Taxonomy |
Several Species of the Enterobacter cloacae complex are widely found in nature, but some can act as pathogens. The biochemical and molecular studies on E. cloacae have shown genomic similarity with six seperate species. Often referred to asEnterobacter Subspecies or 'Enterobacter spp.'
1) Enterobacter cloacae
2)Enterobacter asburiae
3)Enterobacter hormaechei
4)Enterobacter kobei
5)Enterobacter ludwigii
6)Enterobacter nimipressuralis.
E. cloacae and E. hormaechei are the most frequently found in human clinical specimens. Molecular methods of identification are often used to differential between these species.
- ' BASIC TESTS
- ' FOR IDENTIFICATION
- MacConkey growth +
- Indole production -
- Methyl red -
- Voges-Proskauer +
- Citrate(Simmons) +
- Hydrogen sulfide(TSI)
- Urea hydrolysis D
- Lysine decarboxylase -
- Arginine dihydrolase +
- Ornithine decarboxylase +
- Motility (36 °C) +
- D-mannitol fermentation +
- Sucrose fermentation +
- Lactose fermentation +
- Esculin hydrolisis d
- MacConkey growth +
Habitat Information
Enterobacter Cloacae is typically found in nature and is capable of obtaining nutrition from products of organic breakdown and decay. They are often found in environments of soil and sewage, but is also located within the "normal" stomach flora of the human GI tract in 40-80% of the population.
Description and Significance
Describe the appearance (colonial and cellular), possible antimicrobial activity etc. of the organism, and why the organism might be significant.
Enterbacter Cloacae are a genus of straight gram-negative bacilli (rods), capable of lactose-fermentation apart of the family Enterobacteriaceae. Enterobacter spp. are facultatively anaerobic (rods), which have the potential to grow and multiply with or without oxygen. The average cellular size ranges from 0.6-1 μm in diameter and 1.2-3 μm long. E. Cloacae are capable of movement by means of peritrichous flagella, indicating multiple tails for propulsion, and are also acid producers upon glucose fermentation, with an optimal growth temperature of 30 °C. 80 % are encapsulated.
A recent study has shown that the presence of Enterobacter cloacae in the gut may have a strong correlation to obesity likelihood. A decrease 35% to non-detectable levels of the bacterial within the patient’s gut, was linked to a strong reduction in endotoxin load which significantly reduced the patient's weight. A 2012 study where Enterobacter cloacae was transplanted into previously germ-free mice resulted in increased obesity when compared with germ-free mice fed an identical diet, suggesting a link between obesity and the presence of Enterobacter gut flora.
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.
Examination of the genome of E. cloacae shows that the core genome reveals the general physiological and survival genes of the species. Genomic factors in plasmids and variable regions determine the virulence of the human pathogenic E. cloacae strain. Additionally, the diversity of fimbriae contributes to variation in colonization and host determination of different E. cloacae strains.
Genetic analysis further shows that E. cloacae strains possess multiple mechanisms for antagonistic action against other microorganisms, which include the production of various antimicrobial compounds and antibiotic resistance proteins. These give the microbe further fitness advantages in microbial competition, thus allowing it to survive in different environments.
E. cloacae chromosomal DNA consists of 40-60% guanine + cytosine (G+C) nucleotide, the complete E. cloacae subsp. cloacae ATCC 13047 genome contains a single circular chromosome of 5,314,588 bp and two circular plasmids.
Cell Structure, Metabolism and Life Cycle
Interesting features of cell structure; how it gains energy; what important molecules it produces.
Enterobacter Cloacae contain a thin cell-wall peptidoglycan layer of gram-negative bacteria. It its also capable of Nitrate reduction by removing oxygen from nitrate (NO3) producing nitrite (NO2).
Physiology and Pathogenesis
Biochemical characteristics, enzymes made, other characteristics that may be used to identify the organism; contributions to environment (if any).
If relevant, how does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.
endophytic E. cloacae strains have been shown to colonize and benefit plant growth in various crops, such as soybean, cucumber, corn, rice and ginger
E. cloacae is commonly known as a human opportunistic pathogen found in hospitals and causing a wide range of infections, such as lower respiratory tract infections, urinary tract infections, and meningitis. E. cloacae tends to contaminate various medical, intravenous and other hospital devices. Nosocomial outbreaks have also been associated with colonization of certain surgical equipment and operative cleaning solutions.Outbreaks typically occur in Intensive Care Units, primarily affecting weaker patients who are hospitalized for a prolonged periods of time. E. cloacae is clinically significant, particularly because its strains usually carry multiple antibiotic resistance genes. Over the last 15 years, numerous reports have demonstrated their remarkable ability to adapt or acquire resistance determinants and making them some of the most worrying microorganisms of the current antibiotic era.
References
http://www.microbiologyinpictures.com/enterobacter%20cloacae.html
http://www.slideshare.net/AliaNajiha1/enterobacteriaceae-basic-properties
http://www.medscape.com/viewarticle/768204
Author
Page authored by Diego M. Escobedo, student of Prof. Kristine Hollingsworth at Austin Community College.
