Electrophoretic characterization of Clostridium difficile strains isolated from antibiotic-associated colitis and other conditions

Abstract

Clostridium difficile has been recognized as the cause of antibiotic-associated pseudomembranous colitis and of less severe diarrheal diseases associated with the use of antimicrobial agents. However, healthy carriers of this microorganism have been found, particularly healthy neonates and small children. Various typing systems have been used to clarify the epidemiology of C. difficile. We used the electrophoretic patterns of EDTAextracted proteins to characterize C. difficile strains from various sources. Altogether, 110 strains were studied, including 2 reference strains, and 21 different protein profiles were obtained. However, two patterns were the most common: the group 2 pattern, characterized by a major 35-kilodalton polypeptide band, and the group 5 pattern, identified by principal bands of 37 and 56 kilodaltons. The group 2 pattern was characteristic of strains isolated during hospital outbreaks and from sporadic cases of pseudomembranous colitis and antibiotic-associated diarrhea. The group 5 pattern was obtained only from isolates from healthy neonates and children. A correlation between electrophoretic characteristics and virulence can be hypothesized, namely that group 2 strains are more prone to induce diseases and cause outbreaks. It is noteworthy that strains isolated from children with diarrhea of unknown etiology, not related to antibiotic use, belong to the "virulent" group 2; strains from leukemic patients showed a variety of different patterns, and only two belong to group 2. This characterization can be used to aid studies on the virulence and clinical significance of C. difficile.

Phenotypic and Genotypic Diversity of the Flagellin Gene (fliC) among Clostridium difficile Isolates from Different Serogroups

“…Analysis of restriction patterns of DNA of clinical isolates has been used for investigations of epidemiology and typing of C. difficileassociated diarrhea (24). Pantosti et al (37) used the electrophoretic patterns of extracted proteins to characterize C. difficile strains from various sources and showed correlation between certain electrophoretic patterns and virulence. Delmée et al (13) compared serogrouping of C. difficile by slide agglutination with rabbit antisera and polyacrylamide gel electrophoresis of whole-cell proteins, permitting correlation between the two typing systems and establishment of a single classification.…”

Immunoblot analysis of serum immunoglobulin G response to surface proteins of Clostridium difficile in patients with antibiotic-associated diarrhea

“…In all patients, routine stool cultures for common enteric pathogens were negative. Cultures for C. difficile on selective medium (CCFA) and cytotoxin assays were performed by standard procedures (6,13). C. difficile isolates were identified by gas-liquid chromatography and biochemical tests (8), and all were able to produce cytotoxin in vitro.…”

“…on September 13, 2020 by guest http://jcm.asm.org/ Downloaded from SEROLOGIC RESPONSE TO C. DIFFICILE SURFACE PROTEINS Antigen preparation and sodium dodecyl sulfate (SDS) gel electrophoresis. The antigens used in immunoblot assays were surface proteins of C. difficile extracted by EDTA (13).…”

“…Proteins from C. difficile strains isolated from the feces of patients and from a collection strain (C253) representative of the electrophoretic group 2 pattern were separated by SDSpolyacrylamide gel electrophoresis as previously described (13). Gels were stained with Coomassie blue or periodic acid-Schiff stain for carbohydrate detection (3).…”

“…In previous investigations (13,16), we have used electrophoretic profiles of EDTA-extracted surface proteins of C. difficile to characterize different strains of the microorganism. Thus, we were able to demonstrate that most strains from cases of PMC or antibiotic-associated diarrhea, especially when isolated from nosocomial outbreaks, had similar electrophoretic patterns (group 2 pattern), characterized by a major polypeptide band of about 35 kilodaltons (kDa).…”