A Comparative Study of Media Used to Detect Shigella

Abstract

Of 585 Shigella isolates recovered from 565 cases of bacteriologically proved shigellosis, 554 were detected on either desoxycholate citrate agar (DCA) or MacConkey agar (MA), or both. The superiority of DCA over MA was demonstrated, in that 82.7% of the isolates detected in primary DCA and MA cultures were recovered from DCA; the remaining 17.3% were recovered from MA only. Salmonella–Shigella agar (SSA) medium used during one period of the study was found to be of less value comparatively. The results indicate the importance of careful selection of the medium or combination of media used to isolate shigellae, particularly when survey studies are to be used as a basis for comparison of findings.