Autoinfection

AUTOINFECTION (from Greek autos—self and Latin inficere—to infect), self-infection of the organism by bacteria that do not come from the outside world, but live normally on the skin and mucous membranes of the given organism, as well as those which could have remained in a hidden, latent state in various organs and tissues after some previously suffered infectious disease, for example, diphtheria or typhoid fever. Cases of osteomyelitis are known that occurred even several years after having suffered typhoid fever. Autoinfection is possible most often in those cases where there is a breach of integrity or a disorder of blood circulation and nutrition in those organs and tissues in which bacteria vegetate, mainly in the epithelium of mucous membranes and skin. During epidemics, in perfectly healthy individuals who are in contact with the sick, fully viable and virulent microorganisms, the causative agents of the given epidemic, are often found in the oral cavity, nasopharynx, gastrointestinal tract, respiratory tract, etc. (see Bacillus carriage). These microbes, which do not cause obvious harm to their carrier, nevertheless retain their virulence. From this, one can think that the resistance of the carrier against such microbes depends on those features of his organism which characterize acquired immunity. This can be proven by the immune properties of the serum of the given carrier in relation to the species of microbes carried by him. However, under the influence of a whole series of external and internal factors, such an immune state of the carrier's organism can sometimes be disturbed; then the microbe, which had been in a latent state for a long time, causes a specific disease, the autoinfection of the carrier. Such factors weakening the immunity of the carrier can be hereditary weakness and predisposition to diseases, local weakness of various individual organs, insufficient nutrition, excessive physical and mental work causing overexertion, emotional shocks, fright, chronic poisoning with various poisons—morphine, cocaine, alcohol. Furthermore, sudden disturbances of the physical equilibrium of the organism under the influence of trauma, cooling, or overheating can influence the development of autoinfection. The influence of these factors, in turn, can be different depending on age. Thus, the special predisposition of infants to intestinal infections is known. Sex also exerts an influence on the easy possibility of autoinfection; for example, during pregnancy, the menstrual period, and childbirth, a greater tendency of the organism to streptococcal diseases is noted. Upon the action of factors reducing the resistance of the organism, the microbe of the bacillus carrier, which was saprophytic until this moment, causes the disease of the latter. On the skin, one most often encounters staphylococci and streptococci. With general weakening of the organism, autoinfection is expressed by the appearance of general furunculosis, which is especially characteristic of diabetes mellitus. Upon blockage of the sebaceous glands, purulent inflammation of them occurs. Mechanical factors (scratching, irritation of the skin by friction and sweat) also play a large role. Local weakening of tissue resistance is also of significance (e.g., suppuration of blisters in burns). In the nasopharynx, streptococci, staphylococci, meningococci, diphtheria, tuberculosis, and leprosy bacilli can be found in a latent state. In the oral cavity, there is constantly a significant quantity of various types of putrefactive microbes. Streptococci and staphylococci—especially with unhygienic maintenance of the mouth and the presence of carious teeth—can often be the cause of sepsis. One should also mention the latent presence of tuberculosis bacilli in the tonsils. In a large number of cases, the diphtheria bacillus is found in healthy people who have been in contact with the sick. Whereas infection through the oral mucosa occurs more often when it is damaged, the tonsils, thanks to their loose structure, which facilitates absorption processes, even without being damaged, very often are sources of severe infections. Likewise, the nasopharynx, equipped with numerous accessory cavities and passages in which microbes are easily retained thanks to the looseness of the mucosa and the richness of lymphatic pathways, represents the usual entry gate for autoinfection with meningococci. From the intestine, autoinfection most often occurs with the colon bacillus and pyogenic cocci. One also has to observe peritonitis due to perforation in typhoid, round ulcer, appendicitis, and strangulated hernias. Coprostasis, which causes a breach of the integrity of the mucosa, can play a large role. Hemorrhoidal nodes, which are easily traumatized and ulcerated, can also contribute to autoinfection. Among other autoinfections through the intestine, one must mention cystitis, pyelitis, and angiocholitis; in the latter case, traumatic factors (stones), which weaken the tissue of the duct walls, often have great significance. Autoinfection from the genital tract is often observed during various mechanical manipulations (e.g., catheterization), as well as during childbirth.