Clostridium Difficile
In humans, Clostridium difficile can be found in about 3% of healthy adults, as a constituent of intestinal saprophytic flora, and in more significant percentages in infants younger than one year (15-70%).
Pseudomembranous colitis
In the clinical setting. Clostridium difficile is known as the main responsible for a formidable form of colitis, called pseudomembranous colitis, characterized by more or less extensive necrosis, mainly affecting the rectum and sigmoid, and accompanied by often profuse diarrhea.
Of particular concern are some Clostridium difficile strains, called enterotoxigens as they are capable of producing enterotoxin A and / or cytotoxin B. These toxins are internalized by the intestinal mucosa resulting in cell death of the enterocyte.
The spectrum of histological lesions varies from a type I form, characterized by sporadic epithelial necrosis associated with inflammatory infiltrate inside the colon lumen, to a type III form, characterized by diffuse epithelial necrosis and ulcerations covered by greyish pseudomembranes (from referred to as the term pseudomembranous colitis), consisting of mucin, neutrophils, fibrin and cellular debris.
The lethality of the serious Clostridium difficile infection is important, to the point that it is essential to adopt prophylactic measures to stem the spread of the disease in nosocomial environments.
Symptoms
As anticipated, the severity of intestinal infection with Clostridium difficile is variable: symptoms can in fact range from mild to profuse diarrhea (up to 10 liters of serous discharge per day), with toxic megacolon, intestinal perforation, hypokalemia, intestinal haemorrhage, and sepsis. Diarrhea can be accompanied by fever, nausea, anorexia, malaise, pain, abdominal distention and dehydration. Diarrhea can be associated with mucus, blood and fever. Newborns are often asymptomatic carriers: while on one hand colonization seems favored by the immaturity of intestinal bacterial flora, on the other the lack of pathological evolution is due to the inability of the toxin to bind to enterocyte receptors, which are also still immature.
Risk factors
To determine the severity of the infection, in addition to the aforementioned virulence of the bacterium, is also the immune activity of the subject: Clostridium difficile colitis is more frequent in immunocompromised and debilitated subjects, also and above all due to prolonged antibiotic therapies. In fact, these drugs alter the normal microbial flora of the colon, favoring intestinal colonization by Clostridium difficile, which is not by chance responsible for 15-30% of cases of diarrhea associated with antibiotics.
Almost all antibiotics can promote the spread of infection, but lincomycin and clindamycin are mainly involved and, less frequently, penicillins, cephalosporins, tetracyclines, macrolides, chloramphenicol and sulfonamides. Given that knowledge in this regard is constantly evolving, we can more correctly generalize by stating that the risk increases in the case of combined and / or protracted antibiotic therapy, and in general when it involves the use of drugs with a wide spectrum of action.
Furthermore, the Clostridium difficile infection is typically of nosocomial origin: as such it has as a primary target hospitalized patients, especially if they are elderly. Also the drugs used in chemotherapy and the proton pump inhibitors for the eradication of Helicobacter pylori seem to favor Clostridium difficile infection; similar for all the other conditions associated with a reduction in gastric acidity, as happens in patients undergoing particular forms of digestive surgery.
Contagion
The transmission of the disease typically occurs via the fecal-oral route, then through the hands brought to the mouth after contact with contaminated environmental surfaces or with an infected subject. The more severe the diarrhea is, the more the environment where the patient stays will be contaminated.
Thanks to its sporadic shape, the beat can survive for weeks or even months on inert surfaces. Also the contaminated health equipment can be a vehicle of transmission (endoscopes, rectal thermometers, bathtubs ...).
Prognosis and Treatment
The resolution of Clostridium difficile infection leads to an almost complete restitutio ad integrum of the mucosa. Although healing is complete, relapses appear in a high percentage of correctly treated patients, usually within four weeks of the end of antibiotic therapy. In fact, if on the one hand it is necessary to suspend - when possible - antibiotic therapy considered to be responsible for the clinical picture, on the other it may be necessary to resort to other forms of antibiotic therapy, such as that with metronidazole, vancomycin or fidaxomicina (a drug of very recent introduction to the spectrum restricted, specific for treating adults with intestinal Clostridium difficile infections, without significantly altering the physiological intestinal flora).
The rebalancing of salt and water losses is also very important; furthermore, the use of cholestyramine has also been proposed, a drug likely to bind the toxin produced by Clostridium difficile favoring its elimination with feces.
