Anitmicrobial resistance

Broad spectrum drugs

Effective against more than one group of bacteria

Narrow spectrum drugs

Target specific group

Original penicillin

Narrow spectrum and susceptible to microbial counterattacks

Later penicillin

Overcame the limitations of the original molecule

Drug resistance

Adaptive response in which microorganisms tolerate an amount of drug that would normally be inhibitory because of genetic versatility and adaptability

Intrinsic resistance

Natural resistance to anatomical drugs making certain pathogens harder to eliminate

Acquired resistance

Resistance cakes for genetic mutation or by acquisition of resistant genes

Drug resistance started when

Penicillin was developed

Microbes become resistant to drugs when

Spontaneous mutation in critical chromosomal genes OR acquisition of entire new genes or set of genes via horizontal transfer from another species

Chromosomal drug resistance

From spontaneous random mutations. Slight changes in drug sensitivity can be overcome with large doses of drug

Persisters

Slowing or stopping of metabolism so that microbes can’t be harmed by the antibiotic

Resistance through horizontal transfer factors

On plasmid with antibiotic resistant genes can be transferred through conjunction, transformation, transduction

Plasmids encoded in drug resistance are naturally

Present in microbes before they have been exposed to an antibiotic

Natural selection occurs when we have

Drug resistance

Drug resistance long term consequences

• a large microbe population will have few cells with resistance

• As long as the drug doesn’t come into contact genes are not expressed

• If it’s exposed to the drug the resistant population will have a selective advantage

• Offspring inherit resistance

• Replacement populations evolve to have dominant resistance

Antimicrobial drugs are seen as

A cure all for infection

In many instances anti microbial drugs have

No effect or are harmful