Question

Research has uncovered how bacteria which are antibiotic resistant protect bacteria which are not. For example, in an infected wound, an antibiotic resistant Gp A Strep will secrete the bacterial enzyme beta-lactamase. This enzyme will cut apart the beta-lactam ring on penicillins and cephalosporins. It destroys those antibiotics. Any other bacterial species in the wound, even those sensitive to penicillins and cephalosporins, are protected as well.

How could you prove that the growth you saw in the mixed section of the third plate was due to a single organism with antibiotic resistance to streptomycin and ampicillin rather than Strain A secreting a protein which protected Stain S from the ampicillin, and Strain S secreting a protein which protected Strain A from streptomycin?

Answer 1

Bacteria possess a significant genetic plasticity which allows them to respond to a wide array of environmental pressures, comprising the presence of antibiotic molecules which might jeopardize their survival. As mentioned above, bacteria sharing similar ecological niche with antimicrobial-producing organisms are evolved to withstand the effect of harmful antibiotics and their resistance allows them to flourish in their presence. Based on all the previous experiments and observations, the factors that make these bacteria resistant to antibiotics have been inferred. They are I) Modifications of the Antibiotic Molecule either by Chemical alterations of the antibiotic structure or by the destruction of the antibiotic molecule; II) Decreased Antibiotic Penetration and Efflux-which influences decreased permeability and use of efflux pumps to decrease its activity and III) Changes in Target Sites-by increasing the cell protection or by the Modification of the target sites. The major two genetic strategies are to acclimatize the attack are mutations in gene and attainment of foreign DNA coding through horizontal gene transfer (HGT).

Screening methods for the detection of antimicrobial resistance organisms is done by two methods either by morphological analysis or by genetic examination. Some bacteria could change their structure so that antibiotic has no site to adhere to it. Such analysis can be determined by the change in it morphology of that specific organisms. So by analysing its structure through staining, we could easily identify the resistant organism in the mixed plate. The other common successful method is by genetic analysis used to detect ?-lactam genes that is present in organisms.

The occurrence of the AMR genes within the whole-genome sequence (WGS) of colonies could be determined by BlastN-based in comparison against the known set of genes in the reference gene databases, ResFinder and Comprehensive Antibiotic Resistance Database are its examples.

In functional-based analysis, total DNA obtained from the organisms is ligated into plasmids or vectors and transmuted to a host. The resulting clones can harbor information to help identify the resistance genes in the colony.