How Do Bacteria Enter The Body?

Organisms must enter the body to cause disease, and the different ways in which they do so are often referred to as 'the modes of spread'.

Droplet infection:  if organisms are present in the upper air passages they are expelled into the air while speaking, sneezing or coughing, and can then be readily inhaled by others.  Infection can thus easily spread though close proximity to the infected person.  

Infection may spread through handling articles (fomites) which have become infected with the organism, e.g., clothes, bed linen, toys, pencils, etc.  Neglect in washing the hands thoroughly is very likely to spread infection.

The infecting organism may be present in the nasal secretions, faeces and urine.  Lack of hygiene following visits to the toilet may lead to contaminated food or water.  Contamination of water supplies from leaking drains is a potential cause of epidemics.  Flies which feed on excreta are another common means by which food can become contaminated.  

Infecting organisms may be conveyed by means of a blood sucking insect, e.g. by mosquitoes carrying the malarial parasite and lice carrying the typhus organisms.

Certain organisms, especially gonococci and the spirochete which cause syphilis, require actual direct contact between the infected person and the one to be infected.

Finally, infection may spread to man from contact with animals, e.g., rabies from dogs and anthrax from sheep.

Bacteria enter the body by open sores such as cuts and bites. They may also enter though the air into a body if someone near you sneezes, breathes, or coughs near you. Finally, bacteria can also enter the body by water contamination or food contamination (AKA Food poisoning)

Through an open wound whether outside the body or inside.

Swallow it, eyes, ears, nose mouth and skin

Threw any open wound