Aims-To develop a selective supplement for the recovery of thermophilic Campylobacter spp, including Campylobacter upsaliensis from faeces, using campylobacter blood free selective agar base as the growth medium. Methods-Minimum inhibitory concentrations (MICs) of cefoperazone and of teicoplanin were determined for 51 strains of C upsaliensis, 159 strains of other thermophilic Campylobacter spp, and for 66 Enterobacteriaceae (cefoperazone only). From these results a medium using campylobacter blood free selective agar base incorporating cefoperazone (8 mg/l), amphotericin (10 mgIl), and teicoplanin (4 mg/l)-CAT mediumwas formulated and compared with the commercially available campylobacter blood free selective medium (modified CCDA) for isolation of Campylobacter spp from 7000 human faecal specimens. The two media were also compared for the recovery of C upsaliensis from 45 spiked human faeces. Results-Isolation rates of Campylobacter spp other than C upsaliensis were similar for both media, but the CAT medium alone recovered four of the five strains of C upsaliensis from the faecal samples examined. From the spiked faeces specinens, recovery of C upsaliensis was increased by between 35% and over 200-fold on the CAT medium compared with the modified CCDA.Conclusions-CAT selective agar was a suitable alternative medium to modified CCDA for the growth of thermophilic Campylobacter spp, including C upsaliensis from faeces.

The newly developed CAT campylobacter selective medium employing the blood-free charcoal-based agar containing cefoperazone (8 mg l-1), amphotericin (10 mg l-1) and teicoplanin (4 mg l-1) was compared with the membrane filtration culture technique for isolation of Campylobacter spp. including Camp. upsaliensis. Nine hundred and fifty human, 275 dog and 65 cat faeces (in which modified CCDA medium was also compared) were tested. In addition, the recovery of Camp. upsaliensis from pure cultures and from spiked human faeces was examined after membrane filtration. A 50-fold reduction in recovery after filtration using the 0.65 micron filters and a 150-fold reduction using the 0.45 micron filters was found. Recovery of Camp. upsaliensis from spiked faeces was considerably improved using the CAT medium compared with filtration, especially with the lower concentration of organisms (approx. 10(4) cfu mL-1). Campylobacter upsaliensis was recovered from 91 specimens of animal faeces, with CCDA recovering 26 isolates (29%), CAT recovering 76 isolates (84%) and membrane filtration (0.65 microns) recovering 82 isolates (90%). CAT selective agar was found to be a suitable medium for the isolation of thermophilic campylobacters including Camp. upsaliensis from faecal samples.

No abstract

A modified semisolid Rappaport-Vassiliadis (MSRV) enrichment medium was evaluated as an alternative to Rappaport-Vassiliadis (RV) broth for culture of salmonellae from faeces. Faeces from 1544 subjects were cultured using MSRV medium, selective agars, and RV and selenite F enrichment broths. Of the 183 strains of Salmonella spp. isolated, 88% were recovered on MSRV medium, whilst only 59% were recovered using RV broth. When MSRV medium was combined with direct culture and selenite enrichment, 98.9% of salmonellae were recovered. The MSRV culture was found to be easy to read, and in most cases confirmation of organisms as Salmonella spp. could be made 24 hours after receipt of the faecal specimen.

(7 Clin Pathol 1992;45:956-958)