TABLE 3.

MLST of C. difficile from ELISA-negative stool samples determined both directly using total stool DNA and using isolates cultured from the same stools

Sample no.aMLST PCR result (direct)Direct STdCulture resultgCulture STePCR ribotypePaLoc PCR resultlok1/lok3 PCR
22−+6+6005+
23−+15+15010+f
36−+6+6005+
43−+8+8002+
69−+2+2020+
79−+2+2020+
15−+69072+
55−b+1027+
85−c+1027+
99−++15010+f
108−+8002+
  • a The minus sign indicates an ELISA-negative result.

  • b Patient provided a subsequent sample not included in the study (+7 days) that was ELISA positive and ST-1 by culture (sample not typed by direct MLST).

  • c Patient provided a subsequent sample not included in the study (+39 days) that was ELISA positive and ST-1 by culture (sample not typed by direct MLST).

  • d MLST was performed directly from stool samples.

  • e MLST was performed from cultured isolates.

  • f PCR yielded a769-bp amplicon, confirming the absence of the PaLoc.

  • g Crude estimate of viable C. difficile load. +, <100 colonies; ++, 100 to 1,000 colonies; +++, >1,000 colonies.