Kirby Bauer Antibiotic Filter Paper
The Kirby-Bauer Antimicrobial Susceptibility Test Read section II of chapter 26 in your lecture textbook for background on chemical antimicrobial control (for background)—pages 762-763.
Introduction Today you will perform a frequently used procedure called the Kirby-Bauer Antimicrobial Susceptibility test (disc diffusion technique). Each group will inoculate his/her own plate of Mueller-Hinton agar with an assigned culture. To that inoculated plate, you will then aseptically add sterile filter paper discs (using a disc dispenser), which contain a known concentration of antibiotics. As soon as the antibiotic discs touch the agar, the antibiotic will begin to diffuse into the surrounding agar. During incubation the bacteria you inoculated onto the agar …show more content…
Obtain your Petri dish and observe the bacterial growth on the plate. 2. If you have clear areas where bacteria did not grow around your antibiotic discs, these are called 'zones of inhibition.' Turn the plate so that you can place a ruler against the back of the Petri dish and measure the diameter of the zone of inhibition in millimeters. Record your own data in Table 1 below. 3. Using the interpretative key for that antibiotic, determine how susceptible your organism is to the antibiotics (S=Sensitive, R=Resistant, and I=Intermediate). Table 1. Individual Culture Antibiotic Susceptibility S. aureus (SA) Antibiotic Code (on disc) | Antibiotic Name and concentration | Zone of inhibition | Sensitive (S), Intermediate (I) or Resistant ® | GM | Gentamicin 10 | 23 mm | Sensitive | TE | Tetracyclin 30 | 30 mm | ≥19(Sensitive) | E | Erythromycins 15 | 26 mm | ≥23 Sensitive | PB | Polymyxin 300 | 0 mm | Resistance | CZ | Cefazolin 30 | 36 mm | ≥18 Sensitive | NB | Novobiocin 30 | 34 mm | ≥17 Sensitive | Bring your data to the blackboard and enter your data into the tables drawn there.
Record this data on Table
Introduction Today you will perform a frequently used procedure called the Kirby-Bauer Antimicrobial Susceptibility test (disc diffusion technique). Each group will inoculate his/her own plate of Mueller-Hinton agar with an assigned culture. To that inoculated plate, you will then aseptically add sterile filter paper discs (using a disc dispenser), which contain a known concentration of antibiotics. As soon as the antibiotic discs touch the agar, the antibiotic will begin to diffuse into the surrounding agar. During incubation the bacteria you inoculated onto the agar …show more content…
Obtain your Petri dish and observe the bacterial growth on the plate. 2. If you have clear areas where bacteria did not grow around your antibiotic discs, these are called 'zones of inhibition.' Turn the plate so that you can place a ruler against the back of the Petri dish and measure the diameter of the zone of inhibition in millimeters. Record your own data in Table 1 below. 3. Using the interpretative key for that antibiotic, determine how susceptible your organism is to the antibiotics (S=Sensitive, R=Resistant, and I=Intermediate). Table 1. Individual Culture Antibiotic Susceptibility S. aureus (SA) Antibiotic Code (on disc) | Antibiotic Name and concentration | Zone of inhibition | Sensitive (S), Intermediate (I) or Resistant ® | GM | Gentamicin 10 | 23 mm | Sensitive | TE | Tetracyclin 30 | 30 mm | ≥19(Sensitive) | E | Erythromycins 15 | 26 mm | ≥23 Sensitive | PB | Polymyxin 300 | 0 mm | Resistance | CZ | Cefazolin 30 | 36 mm | ≥18 Sensitive | NB | Novobiocin 30 | 34 mm | ≥17 Sensitive | Bring your data to the blackboard and enter your data into the tables drawn there.
Record this data on Table