Too Much Resistance 1. Did the results of the disk diffusion method agree with t
ID: 99788 • Letter: T
Question
Too Much Resistance
1. Did the results of the disk diffusion method agree with the result you obtained with the result you obtained from the Etest diffusion method? Were they both sensitive, intermediate, or resistant? If not, try to explain why you had discrepancies.
2. Why is it important to run control strains of bacteria when testing a bacterium’s susceptibility or resistance to an antibiotic?
3. Did you notice any differences between the Gram-positive S. aureus and the Gram –negative E. coli in their resistance to any antibiotics? If so, what were they?
4. Are the antibiotics you tested effective against fungi, protozoa, or viruses? Explain?
Explanation / Answer
Ans. 1.) Disk Diffusion method is generally applied to check the efficacy of a chemical to reduce the growth of a microbe. It checks the susceptibility of the bacteria against a specific antibiotic. Etest diffusion method is applied on the surface of agar plate which is already inoculated with the test strain. It also determines whether or not a particular bacterium is susceptible against the action of a specific antimicrobial. Both the test based on minimum inhibitory concentration (MIC).
2.) It important to run control strains of bacteria while testing a bacterium’s susceptibility or resistance to an antibiotic because it provides a better observation of the effectiveness of the antibiotic against a given bacterium. Running of control strain of bacteria ensures the mode of action of the antibiotics.
3.) Gram-negative bacteria are more resistant against antibodies than the Gram-positive due to their dense cell wall. Hence, the Gram-positive S. aureus is less resistance than the Gram –negative E. coli in their resistance to antibiotics.
4.) Every antibiotic has its own spectrum. However, some are also capable of killing or inhibiting protozoa, amoebae, rickettsiae etc. For example, metronidazole is active against bacteria and protozoa both. The anti-fungals are quite specific but not active against any other organism. A couple of exemplary antibacterial drug have some action against some protozoa. One has needed to take these things on a case-by-case premise. The antibacterial range of one anti-toxin contrasted with one more of a similar class is regularly remarkable. Generally, antibiotics are not much effective against fungi or viruses. There are several antiviral drugs and numerous antifungal drugs along with antiparasitics.