Iron acquisition by Ornithobacterium rhinotracheale

A putative siderophore receptor of Gallibacterium anatis 12656-12 under Fur control also binds hemoglobin

Pasteurellaceae family members obtain iron directly from host proteins or through siderophore-dependent mechanisms. Although Gallibacterum anatis expresses different virulence factors, its response to growth under iron restriction is unknown. G. anatis cultured in the presence of 2,2′-dipyridyl, up-expressed an approximately 65 kDa protein and repressed the expression of a 70 kDa protein. MALDI-TOF analysis of those proteins indicated homology with CirA (65 kDa), a protein involved in iron-siderophore acquisition in Mannheimia succinoproducens and a TonB-dependent receptor (70 kDa protein), a protein that binds chicken hemoglobin; however, G. anatis siderophore production was not detected by chromo azurol S (CAS)-BHI agar determination. This putative G. anatis siderophore receptor is under Fur control, but not the hemoglobin binding protein, as observed in G. anatis 12656-12 fur mutant (Ω fur 126.13) grown in the presence or not of 2,2′-dipyridyl. The addition of FeCl₃ to the culture medium diminished the growth and biofilm production in approximately 30% and 35%, respectively, in the wild-type strain, but the growth of Ω fur 126.13 strain was not affected and biofilm production increased in 35%. G. anatis Ω fur 126.13 presented lower virulence when it was inoculated to 35-day-old chickens in comparison to the wild-type strain. The induction of more than one iron uptake mechanism could benefit pathogenic microorganisms such as Gallibacterium.

Complete genome sequence of Ornithobacterium rhinotracheale strain ORT-UMN 88

Ornithobacterium rhinotracheale strain ORT-UMN 88 is a Gram-negative, pleomorphic, rod-shaped bacterium and an etiologic agent of pneumonia and airsacculitis in poultry. It is a member of the family Flavobacteriaceae of the phylum Bacteroidetes. O. rhinotracheale strain ORT-UMN 88 was isolated from the pneumonic lung of a turkey in 1995. It was the isolate first used to experimentally reproduce disease in turkeys and has since been the focus of investigations characterizing potential virulence factors of the bacterium. The genome of O. rhinotracheale strain ORT-UMN 88 consists of a circular chromosome of 2,397,867 bp with a total of 2300 protein-coding genes, nine RNA genes, and one noncoding RNA gene. A companion paper in this issue of SIGS reports the non-contiguous finished genome sequence of an additional strain of O. rhinotracheale, isolated in 2006.

Non-contiguous finished genome sequence of Ornithobacterium rhinotracheale strain H06-030791

The Gram-negative, pleomorphic, rod-shaped bacterium Ornithobacterium rhinotracheale is a cause of pneumonia and airsacculitis in poultry. It is a member of the family Flavobacteriaceae of the phylum “Bacteroidetes”. O. rhinotracheale strain H06-030791 was isolated from the lung of a turkey in North Carolina in 2006. Its genome consists of a circular chromosome of 2,319,034 bp in length with a total of 2243 protein-coding genes and nine RNA genes. Genome sequences are available for two additional strains of O. rhinotracheale, isolated in 1988 and 1995, the latter described in a companion genome report in this issue of SIGS. The genome sequence of O. rhinotracheale strain H06-030791, a more contemporary isolate, will be of value in establishing core and pan-genomes for O. rhinotracheale and elucidating its evolutionary history.

Sero-prevalence and identification of Ornithobacterium rhinotracheale in broiler flocks in south-eastern Iran

Ornithobacterium rhinotracheale is a gram negative bacterial pathogen causing respiratory tract infections in poultry. Tracheal, lung and serum samples were obtained from 21 broiler flocks of 8 farms from a slaughterhouse located in south-eastern of Iran. Among 630 tracheal and lung samples from samples resulting from 315 chickens, 11 (3.5%) ORT isolates were identified using biochemical tests. The isolates originated from 9 (42.9%) flocks out of 4 farms. All of the isolates were recovered from tracheal swabs and showed an API 20NE identification biocode 0-2-2-0-0-0-4. Of the 420 serum samples examined by ELISA, 134 (31.9%) sera from 17 (81.0%) flocks were positive for ORT antibodies. These results indicate that ORT is present in most broiler flocks with respiratory disorders in southeast Iran.