Clostridium difficile (CD) is the most common etiologic agent of antibiotic-associated diarrhea. The number of infections has increased dramatically in the last decade. Although the diseases caused by CD are mostly related to health care and antibiotic therapy, some are community-acquired cases. This article explains the pathogenesis of this microorganism, pointing to depletion of intestinal microflora diversity and the inadequate response of the immune system as an important factor predisposing the development of CD infection. Previous published studies have demonstrated an increased incidence of hipervirulent ribotype 027 in Poland and Europe and also the emergence of other ribotypes in various parts of Europe with increased potential for pathogenicity. A high percentage of CD strains, which were isolated in Poland demonstrated resistance to ciprofloxacin, imipenem, erythromycin and moxifloxacin and multidrug resistance. In addition, there was observed a trend to increase in the value of MIC for vancomycin and metronidazole. Factors that may affect the reduction of effectiveness in drug therapy include the sublethal doses achieved in the intestinal lumen, heterogenicity of resistance to metronidazole, the ability to form the biofilms, presence of protein, which repair damaged DNA, transformation of an antibiotic to inactive form and mutations leading to changes to the binding sites of vancomycin.
Keywords: Clostridium difficile; antibiotic therapy; antibiotic-associated diarrhea; antibiotic-resistance.