PCR RIBOTYPING AND ARBITRARILY PRIMED PCR FOR TYPING STRAINS OF CLOSTRIDIUM-DIFFICILE FROM A POLISH MATERNITY HOSPITAL

Detection of the source of Clostridim difficile strains is of importan ce for the control of the nosocomial spread of this microorganism. For this purpose, vaginal and rectal swabs from 183 mothers, duplicate fe cal samples (taken on days 1 and 4 after birth) from 183 neonates, and 94 environmental samples were cultured for C. difficile. The microorg anism was never detected in the meconium obtained on day 1 after birth . On the other hand, an incidence of 17% C. difficile positivity was n oted in the fecal samples obtained on day 4 after birth. Forty-two per cent of the 31 colonized neonates had been delivered with complication s. The bacteria were never encountered in the rectal swabs of the moth ers, and C. difficile was identified in only one vaginal swab. In cont rast, 13% of the environmental samples were positive for C. difficile. No major difference was encountered between patient and environmental isolates with respect to toxigenicity (58 to 65% toxigenic isolates). All strains were subsequently typed by PCR amplification of the 165-2 3S ribosomal intergenic spacer regions and by arbitrarily primed PCR ( AP-PCR) with different primers and combinations thereof, All environme ntal isolates and 11 of 31 neonatal strains were of a single type. The vaginal strain was unique, and among the maternity,ward- and neonate- related isolates, only two additional AP-PCR types were identified. Wh en a collection of C. difficile strains from patients hospitalized in other institutions and suffering from antibiotic-associated diarrhea o r pseudomembranous colitis was analyzed in a similar manner, it appear ed that the strain from the maternity ward was unique. The other strai n commonly encountered among the neonates was also identified frequent ly among the isolates from patients with antibiotic-associated diarrhe a or pseudomembranous colitis, indicating its general occurrence. On t he basis of both epidemiological studies and PCR-mediated genotyping, it was shown that the environment and not the birth canal is the major source of C. difficile acquisition by neonates in this maternity hosp ital setting. Furthermore, AP-PCR appears to be a fast and useful meth od for epidemiologically relevant typing of C. difficile isolates.