The Kirby-Bauer Test

Since bacterium vary in size, structure, shape, and susceptibility to antibiotics, antimicrobial chemicals take issue in their potential and spectrum of activity. Scientists and doctors requisite a substance to efficaciously identify types of pathogens in patients, so they could administer a medicine that would specifically target the organisms. Kirby-Bauer test, excessively cognise as the disk-diffusion method, is the well-nigh widely used way of testing antimicrobial substances. The effectiveness of a certain chem differentapeutic actor is determined by the size of a partition off of ban on an inoculated agar-agar plate. A district of inhibition is the atomic number 18a where a dawn paper disk irritated with an antimicrobial agent set on the agar fold up inhibits growth of inoculated microorganisms. Based on the size of a zone of inhibition and the relation to a specific chemotherapeutic agent used, organisms are classified as sensitive, intermediate, or resist ant. We will strike out which chemotherapeutic agents are most effective against which organisms. My initial hypothesis was that gm-positive bacterium such as staphylococci aureus would be susceptible to many an(prenominal) chemical agents used in the lab, since they lack an outer tissue storey that protects the peptidoglycan cubicle wall. Whereas gram-negative bacteria such as Escherichia coli or Pseudomonas aeruginosa would be more(prenominal) resistant than gram-positive bacteria because they have an outer cellular phone membrane. However, I also hypothesized that polymyxin B might not be as effective to gram positive S.aureus as other chemical agents, because since this agent was typically to bind to Lipid A in the outer cell membrane of gram-negative bacteria, polymyxin B would not be fit to penetrate the thick peptidoglycan layer of S. aureus. Also, we will be equal to(p) to infer the gram scar of my crowds unknown organism found on the relationship in the midst of its sensitivity to other known organisms sensitivities to different antimicrobial agents.\nOur group obtained four small...