Enterobacter aerogenes

Shape: Coccobacillus

Enterobacter aerogenes is short and rod-shaped.

Temperature: 30 degrees Celcius

Out of the three different temperatures tested: 25, 30, and 37 degrees Celsiums, Enterobacter aerogenes grows best at 30
enterobacter_aerogenes.jpg
Gram stain of Enterobacter aerogenes.
degrees Celsius.

Gram Stain: Gram negative

This bacteria has one layer of peptidoglycn with another layer of lipids around it (2 layers). The gram stain came out pink because the outside layer didn't absorb the crystal violet stain but did absorb safranin.

Methyl Red Test: Basic
This bacteria produced basic waste and turned yellow/orange after 48 hours of incubating with glucose.

Motility Test: Motile

Enterobacter aerogenes is motile. Using an innoculating needle with the bacteria on it, a stab line was made through the agar. When the test tube was taken out of the incubator, the stab line was very faint and the bacteria seemed to have moved throughout the agar.
hemolysis.jpg
"A" is a hemolysis result of gamma while "B" and "C" are alpha and beta.

Hemolysis Test: Gamma

This bacteria was gamma. It wasn't alpha or beta because there wasn't any green gunk
growing around the streak line and the edges were clean. It was just one streak line
without anything else growing in the middle of it.

Aerobic Test: Facultative

Enterobacter aerogenes is factultative, which means it can grow with and without oxygen.
During this test a petri dish and a lit candle were placed in a large pickle jar, and the
candle consumed all the oxygen. More samples of the bacteria were placed outside the
jar. Enterobacter aerogenes had grown in both environments.

Antibiotics Test: Chloramphenicol and Hand Sanitizer- success

Penicillin: 0 mm
Chloramphenicol: 30 mm
Ampicillin: 0 mm
Hand sanitizer: 12 mm

The diameter of the ZOI (zone of inhibition) was largest for Chloramphenicol, followed by hand sanitizer. The alcohol in hand sanitizer kills Enterobacter aerogenes by dehydrating the cell wall of the bacteria. In the end, the cell explodes. Chloramphenicol gets in the way of the production of proteins the bacteria need to reproduce, which stops the spread of infection. Penicillin didn't work on this bacteria because it usually stops the production of peptidoglycan. Gram-negative bacteria like Enterobacter aerogenes have a layer of lipids that cover the peptidoglycan, so Penicillin is a lot less effective on gram-negative. Ampicillin didn't work because it is a variation of Penicillin, which means that it kills bacteria the same way.

Environment

Enterobacter aerogenes can be found in many places such as soil, water, and dairy products. It also inhabits the digestive systems of animals and sometimes humans.

Pathogenicity

septic-hip-joint.jpg
Joint in the pelvis infected with Septic Arthritis.

Enterobacter aerogenes can cause bacteremia, lower respiratory tract infections, skin and soft-tissue infections, urinary tract infections (UTIs), endocarditis, intra-abdominal infections, osteomyelitis, ophthalmic infections, and septic arthritis. Septic Arthritis is where bacteria invade joint space. The patient may face death due to the bacteria's destructive tendency if this condition is not found early enough. Septic Arthritis is caused by a bacterial infection from an open wound or joint surgery. Some symptoms are chills, fever, swelling of the infected joint, inability to move the joint, fatigue, severe pain, and extreme warmth. To treat this disease, doctors implant prosthetic joints for the infected areas.


Heather Xiao


Picture sites:
http://microbewiki.kenyon.edu/index.php/Enterobacter_aerogenes
http://www.marietta.edu/~spilatrs/biol202/labresults/hemolysis.html
http://www.aidmyarthritis.com/joint_information/joint_diseases_Septic_Arthritis.php

Resources:
http://www.bookroomreviews.com/2011/02/16/veripur-hand-sanitizer-with-moisturizer
http://www.netdoctor.co.uk/infections/medicines/100000499.html
http://answers.yahoo.com/question/index?qid=20080513141211AA5wvO4
http://sinoemedicalassociation.org/usmle2/FirstAidDrugs.htm
http://microbewiki.kenyon.edu/index.php/Enterobacter_aerogenes
http://emedicine.medscape.com/article/216845-overview
http://emedicine.medscape.com/article/236299-overview