Analysis of selected phenotype properties of Escherichia coli strains isolated from piglets

Pathological E. coli strains are important etiological agents of diarrhea in animals, particularly young pigs. Studies on E. coli bacteria mainly concentrate on identifying their specific virulence markers such as fimbriae and enterotoxins. The study analyzed several phenotype properties of E. coli strains isolated from suckling piglets with and without diarrhea i.e. biochemical profile, the ability to produce hemolysin in-vitro and resistance to commonly used antimicrobial agents. It revealed that E. coli may be classified into 6 biochemical groups differing from each other in at least one test, e.g. the ability to decarboxylase lysine or to ferment lactose, sorbitol, melibiose or arabinose. However, PCR analysis demonstrated that all these bacteria were E. coli possessing the universal stress protein gene (uspA). Strains isolated from pigs with diarrhea (72.1% positive isolates) and those obtained from healthy ones (3.0% hemolytic strains) demonstrated a marked difference in their ability to produce hemolysin on blood agar plates. The analysis of antimicrobial resistance patterns revealed that most strains, isolated from both sick and healthy pigs, were resistant to erythromycin and tylosine, whereas only a few strains were resistant to gentamycin and enrofloxacin. The obtained results indicate that analysing phenotype properties of E. coli recovered from piglets having diarrhoea as well as healthy ones may be important in differentiating these isolates.