Pathogenic Escherichia fergusonii and Staphylococcus gallinarum co-infection in a free-ranging domestic chicken

摘要

Examination was carried out in an emaciated and depressed free-range domestic chicken from Mpwapwa where multiple cases of a similar condition were observed in 2010. A loosely attached unilateral nodule on the ventral aspect of the right eye and similar other nodules around the base of feathers mainly on dorsal aspects of wings, neck and head were observed. The cut nodules were yellowish with a firm and cheesy consistency surrounded by hyperaemic skin. In addition, multiple grey foci of variable size on liver and localized areas of hyperaemia on duodenal mucosa with mucoid exudates in the lumen were observed. On histopathology, the nodular lesions consisted of hyperplastic feather follicles with broad bands of keratinocytes and extension of follicular epithelium into surrounding dermis. In addition, luminal folliculitis in the skin and hepatic portal vasculitis were observed. Excised lesions from the eye, skin and liver were streaked on bacteriological agar with or without penicillin and streptomycin to isolate bacteria. Bacteria grew in agar without antibiotics but not in agar containing antibiotics. Bacterial colonies were subcultured and passaged four times to obtain pure cultures. Based on colony morphology, two types of bacteria were isolated from each of the organs. DNA was extracted from bacteria followed by amplification and sequencing of the 16S rDNA using 27F and 1492R primers. Sequence similarity search in GenBank showed that the bacteria were Escherichia fergusonii and Staphylococcus gallinarum. The present study shows that the chicken had E. fergusonii and S. gallinarum co-infection sensitive to penicillin and streptomycin.ct