Clostridium difficile Toxin A in Infants

C difficile produces two toxins, each of which is cytotoxic and lethal to animals [1]. Whether one or both of the toxins is responsible for pseudomembranous colitis in humans is unknown. C difficile is rarely found in the intestinal tracts of healthy adults, and then only in relatively low numbers. The same numbers of C difficile found in adults with pseudomembranous colitis may be present in infants with no obvious adverse effects [3]. The primary cytotoxin of C difficile, toxin B, may also be found in these infants, but the presence of toxin A, which causes intestinal fluid accumulation and mucosal necrosis in hamsters, has not been demonstrated [3]. However, an ELISA developed in our laboratory has been used to detect toxin A in fecal specimens from adults with pseudomembranous colitis [1]. Using this assay, we attempted to determine whether this toxin might be found in hospitalized infants with no obvious gastrointestinal distress. Ten of the 21 infants tested had toxin A in their feces. No infant had toxin A in the absence of toxin B. This is not surprising, because both toxins are produced in about the same ratio in vitro by all strains of C difficile we have tested [1]. In general, those specimens with high titers of toxin B had correspondingly high concentrations of toxin A. The infant with the highest titers of both toxin A and B was the eight-month-old infant with a clinical diagnosis of antibiotic-associated colitis. The other nine infants with toxin A had no enteric symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)