# Gallibacterium anatis Emerging in Indonesia: Isolation and Molecular Characterization From Chickens in a West Java Poultry Farm

## TL;DR

This study identifies Gallibacterium anatis in Indonesian chickens, showing it causes respiratory and reproductive issues and has key virulence genes.

## Contribution

First molecular evidence of Gallibacterium anatis in Indonesian poultry, including virulence gene detection and phylogenetic analysis.

## Key findings

- 14 out of 17 suspected isolates confirmed as G. anatis via molecular methods.
- All isolates carried the gyrB virulence gene, with high prevalence of gtxA and flfA.
- Sequence similarity of >98.65% with reference G. anatis strains in GenBank confirmed species identity.

## Abstract

Gallibacterium anatis (G. anatis) is associated with decreased egg production and respiratory disorders in chickens. The presence of G. anatis in Indonesia has not been reported. This study aimed to identify G. anatis both phenotypically and genotypically in layer, broiler, and breeder chicken from farms in West Java. A total of 23 suspected gallibacteriosis cases were collected from chickens exhibiting respiratory and reproductive disorders between May 2020 and October 2023. Phenotypic characterization was conducted using blood agar culture, Gram staining, and biochemical tests (catalase, oxidase, and TSIA). Genotypic identification of G. anatis was performed using PCR targeting the 16S‐23S rRNA gene, followed by detection of virulence genes (gtxA, flfA, and gyrB). Sequencing and phylogenetic analyses were carried out using BLAST program and MEGA 7. Among the 23 collected samples, 17 samples showed phenotypic characteristics of G. anatis, and 14 of these isolates (73.9%) were confirmed molecularly. Virulence genes profiling revealed the presence of gyrB (100%), gtxA (93.3%), and flfA (71.4%). Sequence analysis demonstrated more than 98.65% similarity between all isolates and reference G. anatis strains in GenBank, supporting accurate species identification. This study provides the molecular evidence of G. anatis in layer, breeder, and broiler chickens from farms in West Java, Indonesia. The detection of key virulence genes further indicates the pathogen’s potential role in reduced production and respiratory disease in Indonesian poultry. These findings highlight the importance of routine surveillance and molecular diagnostics to support early detection and control strategies for gallibacteriosis in commercial poultry populations.