A bacterial infection is the active or passive penetration of bacteria into a plant, animal or human host , their reproduction there and the reaction of the organism that usually follows after the incubation period has expired in the form of a disease called a bacterial infection .
Bacteria can be taken in from the environment , for example through breathing or food . In humans, the mucous membranes of the respiratory and digestive tracts are particularly often affected. The organ with the highest incidence of bacterial infections is the skin itself due to its nature as a border organ.
Many bacterial infections are harmless, but depending on the germ and, above all, depending on the location and immunity , they can also be very dangerous.
Routes of infection
Bacteria can reach the host via various infection routes, for example via contamination of food and water (see also waterborne diseases ) or (in the case of airborne transmission ) as droplet infection via the breath. If the immune system is weakened, the normal flora (as the entirety of the normally non-pathogenic microorganisms present on external and internal surfaces, which consists largely of bacteria) can lead to a so-called opportunistic disease .
The penetration takes place in turn
- in intact barriers ( skin , mucous membranes ) initially active on a species-specific adhesion ( adherence ) of the bacteria by means of so-called. adhesins of receptors to their target structures.
- passive in the case of damaged barriers.
List of human pathogenic bacteria
- Streptococcus mutans , Streptococcus sobrinus and Streptococcus salivarius are responsible for caries
- Streptococcus pneumoniae with pneumonia , sinusitis , otitis media , mastoiditis , bacterial endocarditis
- Streptococcus pyogenes with the possible diseases: impetigo , erysipelas , phlegmon , sinusitis, otitis media, tonsillitis ; Scarlet fever ; Sepsis , septic shock , necrotizing fasciitis
- Viridans streptococci with bacterial endocarditis (endocarditis lenta)
- Staphylococcus aureus , responsible for invasive infections such as boils , carbuncles , bullous impetigo , wound infections , sinusitis, otitis media, sepsis, septic shock, endocarditis (after heart valve replacement), osteomyelitis , bacterial joint inflammation, pneumonia
- Coagulase-negative staphylococci : Staphylococcus epidermidis and Staphylococcus saprophyticus as opportunists in the normal flora of the skin and mucous membranes
- Staphylococcus intermedius as commensals , especially of the skin of the anal region, facultative pathogen in pyoderma , otitis externa , pyometra , wound infection
- Enterococci ([facultative pathogenic ] urinary tract infections , sepsis and endocarditis )
- Escherichia coli (various infections outside of the intestine [facultative pathogenic] such as urinary tract infections, peritonitis or meningitis )
- Serratia marcescens ([facultative pathogenic] in immunocompromised people: urinary tract infections , sepsis , pneumonia , endocarditis , meningitis , osteomyelitis )
- Haemophilus influenzae with sinusitis,
- Rickettsia ( typhus )
- Neisseria ( meningitis , Waterhouse-Friderichsen syndrome , gonorrhea )
- Bordetelles ( pertussis )
- Corynebacteria :
- Campylobacteria , causing diarrhea
- Borrelia ( borreliosis )
- Treponema pallidum ( syphilis )
- Franciselles ( tularemia )
- Fritz H. Kaiser, Erik C. Böttger, Rolf M. Zinkernagel, Otto Haller, Johannes Eckert, Peter Deplazes: Pocket textbook medical microbiology. 11th revised and expanded edition, Thieme, Stuttgart / New York 2005, ISBN 3-13-444811-4 .
- Peter Fritsch: Dermatology and Venereology. Basics, clinic, atlas (= Springer textbook. ). 2nd Edition. Springer, Berlin / Heidelberg / New York a. a. 2004, ISBN 3-540-00332-0 .