The problem of antibiotic resistance

superbugs = strains of bacteria, viruses, parasites and fungi that are resistant to most of the antibiotics and other medications commonly used to treat the infections they cause.

→ are mutants who after frequent contact with antibiotics for example changed their DNA → become insensitive to the antibiotic → break it down or render it harmless

example: MRSA

The defense mechanisms of our body against microorganisms

immune system

• non-specific defense = the body’s first line of defense against diseases. They are not directed against a particular pathogen.

  • skin = a barrier with the outside world → protects the body in 3 ways of parasat=ic microorganisms

    • The stratum corneum = the outermost layer of the epidermis

    • The sebaceous and sweat glands secrete acidic and antibacterial substances

    • Body’s bacteria compete with foreign bacteria

  • mucous membrane

    • epidermis of body cavities is much thinner than the other skin but is also in direct contact with the outside world →mucous glands protect it →create a thin layer of mucus to prevent access to the underlying tissue

  • white blood cells and cell signaling

    • Macrophages = specialised cells that are involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms

      phagocytosis = The process by which a phagocyte (a type of white blood cell) surrounds and destroys foreign substances (such as bacteria) and removes dead cells.

      example:

      1. Bacteria penetrate the skin via a wound

      2. Macrophages leave the capillaries to attack the bacteria 3. Macrophages phagocyte the bacteria and digest them

      

    • Natural killer cells/ NK-cells = a special type of white blood cells that produce perforin that open and drain infected body cells

      perforin = a protein, released by killer cells of the immune system, which destroys targeted cells by creating lesions like pores in their membranes.

    • Signaling molecules → secreted by infected cells → 2 important functions

      1. attract macrophages and activate NK-cells

      2. warn other cells to create a protein → prevent multiplication of microorganim

• specific defense = consists of mechanisms and agents that target specific antigens

  • characteristics

    1. The detection of antigens

       antigen = a specific molecule (a protein) found in the cell membrane of all cells of any organism (including in the protein coat of a virus)

       • via antigens → immunesystem can recognise foreign cells and viruses = T- and B-lymphocytes → recognise antigen

       • cell membrane lymphocytes have receptor molecules →ability to bind to the antigen = key-lock-principle

    2. building memory

    after an infection → body produces memory lymphocytes → new infection with same microorganism → faster detection → faster reaction of immunesystem → no sickness → immunity gained

  • functions of T-cells or T-lymphocytes

    • have membrane receptors to recognise infected cells → bind with it → perforate cell → cell dies

    • T-cells keep on multiplying upon contact → some turn into memory T-cells

    • T-cells produce signaling molecules → stimulate B-lymphocyte production

  • functions of B-cells or B-lymphocytes

    • recognise antigens → produce antibodies → bind with antigen → create antigen antibody complex →macrophages clean it up

    • B-cells keep on multiplying upon contact → some turn into memory B-cells

How to keep or increase your resistance?

• get enough sleep

• excercise regularly

• have a balanced diet

• avoid smoking, drugs and excessive alcohol consumption

• be cautious with the use of medicines

Immunisation

• active immunisation → vaccines

  • injection of dead or weakened pathogens → encourage the body to make memory cells and antibodies

• passive immunisation → serum therapy

  • injection of anitiserum → presence of antibodies → patient doesn’t produce them → no production of memory cells