Enterobacter Aerogenes - Essay Example

Download file to see previous pages In the meantime it becomes imperative for physicians and surgeons to be vary of selecting the right antibiotic to combat these rogue organisms which play tantrums with them, at times, to the detriment of the patients. One of the most notorious groups of organisms is the Gram -ve bacteria, the most prominent among them being the Enterobacteriaceae.
Enterobacter is a gram-negative bacillus that belongs to the Enterobacteriaceae family. Other members of this family include Klebsiella, Escherichia, Citrobacter, Serratia, Salmonella, and Shigella species, among many others. Enterobacteriaceae are the most common bacterial isolates recovered from clinical specimens. Enterobacter aerogenes is a species found in water, soil, sewage, dairy products, and the faeces of man and other animals. Organisms previously identified as motile strains of Aerobacter aerogenes are now placed in this species. They also have a synonym as Klebsiella mobilis.
As part of the Enterobacteriaceae family, Enterobacter aerogenes is related to E. coli and salmonella. In terms of size, E. aerogenes is smaller than many of its microbial cousins, but its occurrence in hospitals and resistance to antibiotics have made it of particular importance. As E. aerogenes continues to evolve new strains, it will continue to pose challenges to the biomedical community. As a facultative anaerobe, it thrives in environments with little or no oxygen, such as soil, sewage and feces.
Enterobacter aerogenes is a Gram negative rod-shaped bacterium in the same family as Esherichia coli. It can grow on many of the same selective media as Esherichia coli, including: MacConkey Agar, EMB agar and Lauryl-Tryptose broth. E. aerogenes ferments lactose, producing acid and gas like Esherichia coli and is classified as an example of coliform bacteria.
E. aerogenes grows better at temperatures between 34 - 40 degrees C. E. aerogenes carries out 2,3-butanediol fermentation and thus give a positive test in the Voges-Proskauer test while E. coli is negative. E.coli is positive for the indole test while E. aerogenes is negative, this is a very reliable test. 5 E. aerogenes can grow on Simmon's citrate agar while E. coli does not.
There are a lot of similarities between Enterobacter aerogenes and Klebsiella pneumonia. The urease test is one of the few tests that distinguishes E. aerogenes from K. pneumonia. . Klebsiella is positive for urease production while Enterobacter is negative. In the microbiology laboratory, colonies of Enterobacteriaceae appear large, dull-gray, and dry or mucoid on sheep blood agar. All Enterobacteriaceae ferment glucose and, consequently, are able to grow in aerobic and anaerobic atmospheres.
MacConkey agar is a lactose-containing medium that is selective for nonfastidious gram-negative bacilli such as Enterobacteriaceae. Using the enzymes beta-galactosidase and beta-galactoside permeases, the most frequently encountered species of Enterobacter strains ...Download file to see next pagesRead More