Molecular detection and G sequence analysis of using clinical samples of infraorbital exudates from layer chickens with infectious coryza symptoms in Indonesia.

BACKGROUND AND AIM

Infectious coryza (IC) or snot, is caused by and leads to upper respiratory disease in poultry. Various diagnostic methods are available, including isolation and identification through bacterial culture and biochemical tests. However, the isolation and subsequent identification of are challenging because the bacteria are fastidious and require specific growth factors. This study aimed to detect in clinical samples taken from the exudate of the infraorbital sinus of layer hens showing clinical signs of IC.

MATERIALS AND METHODS

Samples were collected from 10 layer hens with IC symptoms. Following DNA extraction, HPG-2 polymerase chain reaction (PCR) assays were performed. The PCR amplicons underwent electrophoresis to determine those of the correct target size (511 bp), and these were sequenced. The resultant sequences were analyzed using the National Center for Biotechnology Information (NCBI) basic local alignment search tool. MEGA X was used for bioinformatics analysis.

RESULTS

The presence of was confirmed by HPG-2 PCR in 4/10 samples. Bioinformatics analysis showed that the amino acid sequence of the samples and the reference sequences in the NCBI database were grouped within the same cluster. Furthermore, the nucleotide sequences showed 98.64%-100% of similarity with the reference sequences. The phylogenetic reconstruction of partial G sequences from 55 strains/isolates deposited in GenBank confirmed that the four HPG-2 PCR-positive samples fell within the cluster, separate from the , spp., and clusters.

CONCLUSION

infection was molecularly confirmed in 4/10 (40%) samples by HPG-2 PCR amplicon detection. Clustering of the G partial gene sequences revealed that the positive samples fell within the cluster.