The work shows the data of monitoring research on diagnosis of enterohaemorrhagic Escherihia coli (EHEC) О157:Н7 among the cattle on the farms of Irkutsk region. Mass gastrointestinal diseases of newborn calves causes large economic damage to farms of Russia including Irkutsk region. Etiology of these diseases is ambiguous. The task is also complicated by the fact that along with well-studied agents enterohaemorrhagic serotypes of Escherichia became wide-spread. Detection and diagnosis of these in veterinary science nowadays is not as common as in medicine. The most wide-spread and significant for the healthcare EHEC variation is the serovar О157:Н7.

The aim of the work was monitoring research on diagnosis of enterohaemorrhagic E. coli (EHEC) О157:Н7 among the cattle on the farms of Irkutsk region, determination of susceptibility/resistance of the isolates against modern antimicrobial preparations.

At present to indicate and diagnose EHEC DNA-testing (PCR) or immunofluorescence assay is efficiently used. However, the usage of these is limited to large diagnostic centres specialized on veterinary science. Analysis of literature and experimental data allow to suggest immunochromatographic method as a more efficient alternative according to several criteria. The work presents scientific evidence and first shows a possibility to use "E. coli О157:Н7 Test" test systems produced by Novated Ltd (Israel) for express diagnosis of colibacteriosis, etiological factor of which is EHEC О157:Н7. These diagnostic test systems are used in the healthcare of EU countries. It is crucial, that analysis with the use of the test systems can be done at the farm locations exactly at the centres of infection with high speed and accuracy.

It was established, that adult animals are reservoirs of Е. coli О157:Н7. Calves in which EHEC was detected had symptoms of acute intestinal infection. This diagnosis was proved by biochemical, haematological and bacteriological research. 35 strains of EHEC О157:Н7 were determined and it was shown, that the isolates are resistant to most antimicrobial preparations of different groups of chemical substances. . The separated isolates possess the highest susceptibility to antibiotics of the cephalosporin group of various generations (I-IV). Susceptibility to b-lactam antibiotics was shown by 28 strains (80.0%), to cephalosporins - 31 strains (88.6%), to tetracycline antibiotics - 16 strains (45.7 %), to aminoglycosides - 11 strains (31. 4 %), to polypeptides - 4 strains (11.4 %), to fluoroquinolones - 11 strains (31.4 %), to nitrofurans - 21 strains (60 %). First experimental in vitro and in vivo results were also received with the use of veterinary preparation Trametin, developed at the Irkutsk affiliate of the Institute of experimental veterinary science of the Russian academy of agriculture. It is produced with liquid-phase fermentation of xylotrophe fungus Trametes pubescens (Shumach.:Fr.)Pilat.. It was shown, that 22 strains (62.9 %) are susceptible to Trametin. Experimental data give evidence that it is reasonable to use Trametin to treat colibacteriosis, etiological factor of which is EHEC О157:Н7. In this case medical efficiency reaches 88.2%, livestock preservation - 100%, treatment period decreases to 4-5 days, treatment course costs 165 rubles, that is incomparable to the use of other preparations. Preventative measures keep the livestock preservation at 100%, economic efficiency is 10.3 rubles per 1 ruble of expenses.

Thus, the most practical way is to introduce and use used immunochromatographic method of EHEC identification with test systems, that will allow a quick, efficient and economical monitoring for circulation of EHEC at commercial farms of the Irkutsk region. For the first time it was discovered that EHEC О157:H7 is detected in cattle of all age groups at commercial farms of the Irkutsk region and cause acute type of colibacteriosis of young calves, which is often lethal. Having said that, the determined EHEC strains are poliresistant to antimicrobial preparations used at the farms of the Irkutsk region, which explains circulation of intestinal infections at the commercial farms for many years. Today it is essential to use multifunctional medical and preventative preparations developed and produced in the region with ecological technologies, including Trametin, produced on the base of xylotrophe fungus T. pubescens using modern methods of biotechnology, in the system of control of colibacteriosis of calves.