Question

write a short nots on "natural resistance" ?

Answer 1

Antibiotic resistance tests: Bacteria are streaked on dishes with white disks, each impregnated with a different antibiotic. Clear rings, such as those on the left, show that bacteria have not grown—indicating that these bacteria are not resistant. The bacteria on the right are fully susceptible to only three of the seven antibiotics tested.[1]

Antimicrobial resistance (AMR or AR) is the ability of a microbe to resist the effects of medication that once could successfully treat the microbe.[2][3][4] The term antibiotic resistance (AR or ABR) is a subset of AMR, as it applies only to bacteria becoming resistant to antibiotics.[3] Resistant microbes are more difficult to treat, requiring alternative medications or higher doses of antimicrobials. These approaches may be more expensive, more toxic or both. Microbes resistant to multiple antimicrobials are called multidrug resistant (MDR). Those considered extensively drug resistant (XDR) or totally drug resistant (TDR) are sometimes called "superbugs".[5]
Resistance arises through one of three mechanisms: natural resistance in certain types of bacteria, genetic mutation, or by one species acquiring resistance from another.[6]All classes of microbes can develop resistance. Fungi develop antifungalresistance. Viruses develop antiviralresistance. Protozoa develop antiprotozoalresistance, and bacteria develop antibioticresistance. Resistance can appear spontaneously because of random mutations. However, extended use of antimicrobials appears to encourage mutations which can render antimicrobials ineffective.[7]