Lekooporno?? na wybrane chemioterapeutyki szczepów Escherichia coli izolowanych od prosi?t

摘要

Escherichia coli constitutes an important factor contributing to the development of secretory diarrhoea in piglets resulting from the drug-resistance of some strains of these bacteria to some antibiotics applied in the treatment of this disease in this group of animals. The performed investigations aimed at determining selected phenotypical characters of E. coli isolates isolated from piglets showing diarrhoea symptoms, as well as from healthy individuals without the intestinal form of colibacteriosis. The performed investigations comprised 103 E. coli strains obtained from rectum swabs taken from 103 suckling piglets (1-7 days of age) showing diarrhoea symptoms. The control included 54 bacterial strains isolated from piglets (1-7 days of age) showing no clinical diarrhoea symptoms. With the assistance of an API 20 E kit, 18 biochemical traits were determined which made it possible to ascertain the examined isolates as E. coli. On the basis of a number of biochemical traits of the examined strains, the following three groups were identified: A, B and C. The applied PCR test to check the presence of the uspA gene typical for the E. coli revealed that all the analysed bacterial isolates, regardless of the obtained biochemical profile, were capable of amplification of the product fragment of 884 bp mass, including them to E. coli species. In order to assess their capability for haemolysis, the bacteria were sown onto an agar-based substrate supplemented with 5% ram blood. It was observed that majority of isolates derived from sick piglets showed the following haemolytic properties: 86.7% (profile A), 90.2% (profile B) and 58.8% (profile C). In the case of healthy piglets, two profiles exhibited haemolytic capabilities, namely: profile A (9.1%) and profile B (5.9%). The tested isolated were characterised by different degrees of resistance to antibiotics applied in experiments. Low in vitro ery-thromycin effectiveness was recorded. The proportion of resistant isolates amounted to 98.1% in sick piglets and to 96.3% in healthy ones, but these differences were not statistically significant (P < 0.01).