Albena Dimitrova, Simeon Yordanov and Krasimira Petkova
National Diagnostic Research Veterinary Medical Institute, 1606 Sofia, Bulgaria
Dimitrova, A., Yordanov, S. & Petkova, K. (2021). Characterization of Escherichia coli strains isolated from pigs in semi-industrial swine farm importing gilts pigs from western European country. Bulg. J. Agric. Sci., 27 (3), 608–614
In a semi-industrial pig farm importing gilts sows from France, where the respiratory disease complex (PRDC) is a problem and was registered enzootic flowing of colibacteriosis (CB) was carried complexes examination on the characteristics of the persistent E. coli strains. Three times through 6 months, organ samples (OS) and rectal swabs sample (RSS) were collected from pigs 1-10, 11-20, 21-30 and 31-45 days of age, that were tested bacteriologically for E. coli. The received isolates were typified and tested for susceptibility to 17 antimicrobial means.
Isolated were 37 strains of E. coli from 7 serogroups, of which O8, O20 and O157 defined as “old” and O74, O136, O148 and O159 as “new”. In most cases, the strains were in different combinations but almost always positive for F4 and F5 and less often for F6. Strains of serogroup O8 persisted from the first to the 45th day after birth; – from O20 and O136 – from birth to weaning at 30 days; – from O159 – from 11th to 20th day; – from O157 – from 11th to 45th day; – from O148 – from the 21st day to weaning at 30 days; and from O74 – only after weaning, from the 31st to the 45th day. Isolated E.coli strains were sensitive to most of drug means of the groups of aminoglycosides, amphenicoles and fluorinated quinolones as well as to the sulfamethoxazole+trimethoprim combination. In some of them was registered increased sensitivity compared to past periods. Except to beta-lactams, many of the strains are also resistant to tetracyclines, macrolides, streptomycin and colistin.