Antibiotic resistance

Antibiotics recap’ Mechanisms of resistance resistance Resistance plasmids and multi-resistance Antimicrobial stewardship

what is Antibiotic resistance

The acquired ability of microorganisms to resist the effects of antibiotics that they were previously sensitive to.

what does Bacteriostatic mean

The ability of antimicrobial agents to inhibit the growth of bacteria.

what does Bactericidal mean

The ability of antimicrobial agents to kill bacteria.

Four main classes of antibiotic targets

• Cell wall synthesis

• protein synthesis

• metabolic pathways

• nucleic acid synthesis.

what are the reasons for resistance to antibiotics

• Natural (lack of target structure, impermeability to antibiotics)

• acquired (enzymic inactivation, modification of target, acquisition of efflux mechanism).

what is Horizontal gene transfer

The process by which microorganisms acquire the ability to become resistant to antibiotics through transformation, conjugation, or transduction.

explain transformation (in bacteria’s ability to become resistant to antibiotics)

 extracellular naked DNA is taken up by cells that have developed genetic competence

explain conjugation (in bacteria’s ability to become resistant to antibiotics)

• a gene transfer process in which a recipient bacterium receives DNA from a donor bacterium by cell-to-cell contact through conjugative pili.

• Conjugation is mediated by certain plasmids or transposons.

explain transduction (in bacteria’s ability to become resistant to antibiotics)

• Transduction is the process by which foreign DNA is introduced into a cell by a virus or viral vector.

what are Biofilms

Bacteria that are less susceptible to antimicrobials compared to planktonic bacteria.

what is antimicrobial stewardship

• Practices to ensure appropriate and responsible use of antibiotics

demonstrate some practices Antimicrobial stewardship

• not starting antibiotics without evidence of bacterial infection

• using local guidelines

• documenting antibiotic use

• obtaining cultures before prescribing

• reviewing the need for antibiotics within 48 hours.

Causes of antibiotic resistance

• Overuse of antibiotics

• improper disposal

• traveling (spreading resistant bacteria)

• lack of hand washing.

what are Biochemical mechanisms of antibiotic resistance

• Overproduction/alteration of target

• alternative pathway

• decreased influx/increased efflux

• drug modification,

• drug destruction.