Antibiotic Sensitivity In Bacteria

Antibiotic Sensitivity In Bacteria

ANTIBIOTIC SENSITIVITY IN BACTERIA

Bio 120 – Lab, 6th April 2011
Background
Bacteria are microscopic organisms whose single cells have neither a membrane-enclosed nucleus nor other membrane-enclosed organelles like mitochondria and chloroplasts. They get nutrients from their environments in order to live. They are prokaryotic and have only one chromosome. They are usually classified into 3 groups on the basis of shape, Bacilli (rod shaped), Cocci (spherical) and Spirilla (curved walls). They can also be classified according to their gram stain. Gram-Negative bacteria’s cell wall contains a thinner layer of peptidoglycan surrounded by an outer membrane, while the Gram Positive bacteria have a thicker cell wall.
Escherichia coli (E.Coli) is a gram-negative Bacillus bacteria most commonly found in the normal flora of the intestinal tract in humans and animals helps in digestion of food. Though usually not harmful, in a study done by Hudault S, Guignot J, Servin AL (July 2001) it was found that,’ E.   coli can cause infection in the urinary tract and brain stem (meningitis) as well as intestinal diseases referred to as gastroenteritis.’
Micrococcus is a Gram-positive Cocci that are 0.5 to 3.5 micrometers in diameter and usually arranged in tetrads or irregular clusters. M. Luteus can be found in many places such as the human skin, water, dust, and soil. Micrococcus is generally thought of as harmless bacterium, but there have been rare cases of Micrococcus infections in people with compromised immune systems such as HIV patients.
Antibiotics are medicinal products that have an anti-bacterial effect. They could be both synthetic and semi-synthetic and can destroy or inhibit the growth of other microorganisms especially bacteria. “The wide application of antibiotics in human and veterinary medicine has led to large-scale dissemination of bacteria resistant to antibiotics in the environment.” (Reinthaler, Posch, et.al., 2003). Antibiotics allow...