Biological characteristics and pathogenicity of avian Escherichia coli strains from albanian poultry flocks

A total of 129 pathogenic Escherichia coli strains (APEC) isolated from hens and broilers suffering from colisepticaemia and ovaritis were studied regarding their biological and pathogenic characteristics such as serogroups and virulence associated genes. For comparison were studied also other 100 poultry fecal E.coli strains originated from apparently healthy birds. Serotyping demonstrated that most of E.coli strains were untypable in both colibacillosis clinic division groups (62% for and 34%, whereas in 129 of E. coli strains the searched eight virulence genes for their presence showed relationship with colibacillosis infection outbreaks in poultry. Serotyping identified a very wide variety of serotypes according to APEC and AFEC strains. Serotypes most often associated with the presence of clinical signs resulted O86 (8, 75%), O2 (4, 86%), O8 (6, 77%), O15 (3, 88%), O139 (2, 92%) ; O157 (2.92%) 78 O (1, 94%), while those with apparently healthy birds: O8 (11, 53%), O157 (7, 69%), O73 (3, 85 %), O86 (3, 85%), O115 (3, 85%) and O2 (3, 75%). The lack of virulence factors in APEC strains resulted 18, 05%, while in AFEC strains 81, 95%. This study identified significant differences of virulence factors among strains isolated from lesions, compared to those from apparently healthy subjects. Anyway the detection of virulence genes present in serotypes O15, O86, O73, O101, O147, O157, brings a wider variety of APEC in serogroups classification. These data obtained from genetic characterization of avian E.coli strains constitute the first report in Albania, for colibacillosis infection outbreak in poultry flocks. The presence, appearance and distribution of virulence genes in poultry flocks, provides basic information for the control and eradication of the colibacillosis infection. Application of molecular biology methods to further knowledge of the serotyping data now is a time requirement for the prevention and eradication of avian colibacillosis or other bacterial poultry infections.