Risk assessment of different Gallibacteria species

Gallibacterium anatis, G. melopsittaci, G. salpingitidis, and G. trehalosifermentans belong to the Pasteurellaceae family and the Gammaproteobacteria class. These Gram-negative, non-motile, rod-shaped or pleomorphic bacteria are mesophilic, facultatively anaerobic, or microaerophilic, and do not form endospores. Gallibacteria have been shown to colonize the mucous membranes of the upper respiratory tract and lower genital tract of various bird species, causing serious diseases such as blood poisoning, oviductal, nasal, pericardium, and pneumonia. G. anatis can be transmitted both horizontally, presumably via the respiratory route, and vertically. G. anatis is considered the main cause of inflammation of the ovaries, oviducts, and peritoneum, as well as reduced egg production and mortality in laying hens. The bacteria show a lower prevalence in other bird species such as turkeys, ducks, geese, pigeons, and various wild birds. G. anatis strains have also been detected in non-avian hosts such as cattle, horses, sheep, rabbits, and humans. The pathogenicity of the hemolytic biovar of G. anatis is primarily caused by the toxin GtxA (Gallibacterium toxin A). Cell culture experiments showed that GtxA can lyse bird red blood cells and has leukotoxic effects. In addition to GtxA, G. anatis expresses other virulence factors, whose role in pathogenicity has not yet been fully elucidated.

To date, three cases of disease in humans have been linked to G. anatis. All of the patients infected with G. antanis suffered from underlying medical conditions.

Unlike G. anatis, representatives of the species G. melopsittaci, G. salpingitidis, and G. trehalosifermentans have so far only been phenotypically characterized and taxonomically classified. Isolates of G. melopsittaci and G. trehalosifermentans originate from parakeets suffering from septicemia. G. salpingitidis isolates have so far been cultured from ducks with oviductal inflammation, geese with peritonitis or septicemia, and from a cat with pericarditis.

In the Technical Rules for Biological Agents (TRBA) 466 “Classification of Prokaryotes (Bacteria and Archaea)”, G. anatis, G. melopsittaci, G. salpingitidis and G. trehalosi-fermentans are classified in risk group 2 according to the Biological Agents Ordinance with the index t (pathogen for vertebrates; humans are not affected under natural conditions).

According to Section 5 Paragraph 1 GenTSV in conjunction with the criteria in Annex 1 GenTSV, the ZKBS classifies G. anatis, G. melopsittaci, G. salpingitidis and G. trehalosifermentans as donor and recipient organisms for genetic engineering work of the Risk group 2 This species of the genus Gallibacterium can cause serious illnesses, especially in birds in the livestock sector, and can lead to reduced egg production and increased mortality in infected laying hens, for example. Gallibacteria have also been detected in mammals, including humans. However, these latter cases are rare and have so far only affected individuals with pre-existing medical conditions.

The ZKBS statement can be found at File number 45241.0214 can be retrieved.