Clonal diversity and zoonotic potential of MDR Escherichia coli isolated from poultry at different age intervals.

1. A pool of 480 E. coli isolates of poultry (broilers and ducks) representing different time intervals (0, 10, 20 and 30 days) was selected for ribotyping and used to determine polymorphism of 16-23S ribosomal RNA intergenic space. All the isolates were multidrug-resistant (MDR).2. Out of these, 10 isolates were tested for MultiLocus Sequence Typing (MLST) among which novel allelic combinations and therefore new sequence types were identified in seven isolates.3. This work showed the changes in E. coli strains structure at farm level and individual bird level in host species raised on organised farms with similar parental lineage and environmental housing. The statistical results showed that the structure of variation is very different by farm, supporting a strong effect of location, which confirms the temporal clustering.4. There were significant differences between E. coli strains in chickens and ducks, indicating host specificity of the E. coli strains.5. Some of the pathogenic E. coli strains found using MLST belonged to ST735, ST2796 and a pandemic clone ST752 of ST10 clonal complex. The results strongly suggested the clonal expansion and establishment of specific MDR clones that have zoonotic relevance.

RNA profile and structural protein analysis of rotaviruses isolated from diarrhoeal calves in India.

Two isolates of group A rotaviruses (CR129 and CR156) were isolated from faecal samples of diarrhoeal calves reared in two dairy farms at Hisar (Haryana, India) by using MA-104 cell lines. These isolates were compared with three standard reference bovine rotaviruses, UK, NCDV and B223, to reveal differences, if any, in their genome and protein migration profiles. The migration of RNA segment 4 of CR129 was slower than that of NCDV, but faster than that of UK. Segment 10 of CR156 moved faster than that of the reference viruses. The segments 2 and 3 co-migrated in CR129, but resolved separately in CR156. Five protein bands of size 116-120 KD (VP1), 95 KD (VP2), 90 KD (VP3/VP4), 44 KD (VP6) and 34 KD (VP7) were detected by protein analysis. No significant difference was observed in the protein profile of these two bovine rotavirus isolates by immunoblotting. However, VP1 was of approximately 116 KD size in the two isolates, compared to 120 KD in the reference strains. These findings indicate that these rotaviruses isolated from diarrhoeic Indian calves differed from the 3 reference strains.