Chemotherapeutic Agents Practical: Disc Diffusion and Broth Dilution Method

Chemotherapeutic Agents Practical
Student's Name
Course name: Course code
Professor's Name
Date
Introduction
Pharmacologists must understand sensitivity and specificity investigations, as well as the fundamentals of synergy and antagonism while creating novel antimicrobial therapeutic regimens. In vitro susceptibility testing on a variety of antibiotics suited for treating these bacteria at that specific body site is used to recommend appropriate antibiotic therapy. A few procedures were used in our experiments: reading the Etest strip, demonstration of antimicrobial synergy, which tested if their combined activities were greater than the sum of their individual activities, and demonstration of antimicrobial antagonism, which tested if the presence of the other harmed one drug's activity.
 
Materials and Methods
Protocol 2 involved a demonstration of antimicrobial synergy and antagonism. For this experiment, both the broth dilution method and the disc diffusion were used to demonstrate antimicrobial synergy, enhanced inhibitory action or antimicrobial resistance, and reduced inhibitory activity (1). 
The first methodology used two primary techniques to exhibit antibacterial cohesiveness: The Disc Diffusion Method and the Broth Dilution Method. A sterilized swab was utilized for the Disc Diffusion Method. On a DST agar plate, some E. coli suspension from the previous experiment (step A.7) was added. Sulphamethoxazole and trimethoprim antibiotic discs were then inserted, separated by 1cm, and sterilely placed on the agar plate. They were then incubated for 24 hours at 37°C, after which zones of inhibition were seen and measured.
Penicillin and gentamicin were used to demonstrate synergy in the serial dilutions using broth. In rows 1 and 2 of a 96-well dish, pits 2-12, 50 µl of nutritional broth were introduced. Each row of wells 1 and 2 received 50 µl of penicillin solution (concentration 80 g/ml). Each well of raw two only received 5 µl of gentamicin solution (concentration 100 g/ml) after penicillin from 2-12 in each row had been doubly diluted. After that, three colonies from the plate given were emulsified in 3 ml of sterile distilled water to make an Enterococcus faecalis solution. In wells, 2-12 of each row, 50 µl of the bacterial rest were added. Finally, incubation of the 96-well plate at 37oC for 24 hours and later on, observation of the MIC of penicillin alone occurs and that of penicillin with gentamicin (2).
Making a Proteus mirabilis suspension by emulsifying three colonies in 3 mL normal saline and proving Antimicrobial Antagonism was the alternative option (3). Afterward, the portion of the culture was transferred to a DST agar medium swabbing with a sterilized swab. Antibiotic discs containing nalidixic acid and nitrofurantoin, isolated by 1 cm, were placed on the DST plate. The inhibitory zones were observed and recorded after a 24-hour incubation period at 37°C. 
The Etest strip was imbued with a calibrated range of antibiotic concentrations, allowing the MIC to be read at the point where the bacterial growth zone crossed the strip. The final MIC tetracycline findings for E. coli were read and recorded.
Results
For the Disc D...