Lecture 11

What is a superbug?

A superbug is a strain of bacteria that has developed resistance to most of the antibiotics used to treat it.

How do bacteria become resistant to antibiotics?

Bacteria can become resistant to antibiotics through mutations in key genes that change the affinity of the target for antibiotics. Antibiotic resistance can also be acquired through the horizontal transfer of antibiotic-resistant determinants.

What are some anthropogenic drivers of AMR?

Anthropogenic drivers of AMR include farming practices (such as the use of antibiotics as growth promoters in animals), healthcare practices, and overprescription of antibiotics for pets by veterinarians.

Why is overprescription of antibiotics a problem?

Overprescription of antibiotics can lead to the development of antibiotic-resistant strains of bacteria, which can spread in the community and make it more difficult to treat infections.

What is the disadvantage of using gram staining for strain differentiation?

The main disadvantage of using gram staining for strain differentiation is that it has poor species resolution.

What is biotyping and what are its advantages and disadvantages?

Biotyping is a method used to differentiate different strains of bacteria based on their metabolic activity, ability to produce different enzymes, and ability to grow under different conditions. The advantages of biotyping are that most strains are typeable, it is reproducible and relatively easy to perform and interpret. The disadvantage of biotyping is that it has poor discriminatory power due to variation in gene expression and point mutation that can alter metabolic activities.

What is phage typing and what are its advantages and disadvantages?

Phage typing is a method of strain differentiation that involves applying different bacteriophages to bacteria and identifying the phages that produce lysis. The advantages of phage typing are that it is fairly reproducible, has good discriminatory power, and is easy to interpret. The disadvantage of phage typing is that it requires maintenance of biologically active phages and is only available at reference centers.

What is serotyping and what are its advantages and disadvantages?

Serotyping is a method of strain differentiation based on the binding of antibodies to the cell surface antigens of bacteria. The advantages of serotyping are that most strains are typeable, and it allows differentiation between strains that may be closely related by other methods. The disadvantage of serotyping is that some autoagglutinable strains are untypeable and some methods of serotyping are technically demanding.

What are some molecular nucleic acid-based techniques for strain differentiation?

Some molecular nucleic acid-based techniques for strain differentiation include random amplification of polymorphic DNA (RAPD), pulsed field gel electrophoresis (PFGE), and amplified fragment length polymorphism (AFLP).

Why is understanding the genetic relationships of strains important for controlling disease spread?

Understanding the genetic relationships of strains can help identify sources of infection, track outbreaks, and develop targeted interventions to prevent the spread of disease.