[Sensitivity of different strains of E. coli and Shigella to the inhibitory action of Ploskirev's bactoagar].

A study was made of the sensitivity of 190 strains of E. coli and 107 strains of Shigellae of different serological types to the inhibitory action of Ploskirev's bactoagar on the capacity of these bacteria to form colonies. The strains under study proved to be nonhomogenous in this respect: between different strains of E. coli there were revealed 10-, 100- and even 1000-fold differences by this property; the differences between Shigellae strains were less marked--in over 90% of Shigellae strains the capacity to form colonies was depressed less than 4-fold. Only with the aid of some of E. coli and Shigellae strains was it possible to detect differences between the tested 20 commercial Ploskirev's bactoagar batches. Apparently, the use in practical bacteriological laboratories of accidental strains of local origin for control of Ploskirev's bactoagar could not aid in improving the quality of the medium, and consequently bacteriological diagnosis of infections.