[The distribution of fleas of the genus Xenopsylla in the Ustyurt].

The distribution areas of the main plague vectors of Xenopsylla fleas (X. skrjabini, X. gerbilli, X.

[Trial use of polymyxin and erythromycin for isolating cultures of the plague microbe in the Kyzyl-Kum].

It is recommended that the Hottinger agar medium with polymyxin or erythromycin be used for isolation of pure cultures of the plague microbe from specimens containing various species of microorganisms, except Proteus. Such a procedure was used in the Kizil-Kum for the bacteriological examinations with respect to plague. The procedure may be used in the natural foci with the strains resistant to these antibiotics.

[Response, to polymyxin, of plague microbe strains isolated from various natural foci and of their mutants with a decreased requirement in nutritional factors].

Investigation of the response to polymyxin of 65 strains of Pasteurella isolated from various foci and 46 their back mutants showed that all of them were usually highly resistant to polymyxin (MIC 200--500 micrograms/ml). The Pasteurella strains isolated in the Gissaro-Darvaz natural focus, Turkey and Congo were highly sensitive to polymyxin (MIC 10--25 micrograms/ml). Single cultures highly sensitive to the antibiotic were detected among the polymyxin-resistant strains.