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- Jonare, Liv, et al.
(författare)
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Core genome multilocus sequence typing (cgMLST) confirms systemic spread of avian pathogenic Escherichia coli (APEC) in broilers with cellulitis
- 2023
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Ingår i: Veterinary Microbiology. - 0378-1135 .- 1873-2542. ; 282
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Tidskriftsartikel (refereegranskat)abstract
- Broiler cellulitis has emerged as an important cause of economic losses for farmers and slaughter plants from carcass condemnation at processing. Avian pathogenic Escherichia coli (APEC) has been identified as the main causative agent. The aim was to characterize E. coli isolated from cellulitis and organs in broilers at slaughter by whole genome sequencing analysis to study if systemic spread could be confirmed. Isolates were collected postmortem from 101 carcasses condemned due to dermatitis/cellulitis from five commercial farms and six flocks. Forty-six isolates were characterised to determine serotypes, sequence types and virulence-associated genes. Analysis by cgMLST was performed to study the genetic similarity between isolates from the same broiler, among birds from the same flock and between flocks. Escherichia coli was isolated from 90% of birds from subcutaneous samples. In 20 broilers, E. coli was isolated from organs in pure culture or mixed with sparse growth of other bacteria. In eight of these, there were post-mortem findings suggestive of systemic bacterial spread. The majority of the isolates from the same bird and flock belonged to the same serotype and sequence type and were genetically indistinguishable, but differed when compared between flocks. Common APEC virulence genes, i.e. chuA, fyuA, hlyF, iroN, irp2, iss, ompT, sitA, TerC, TraT, were present in > 87% of the isolates. We conclude that evidence of systemic spread of E. coli from cellulitis was present in some birds at time of slaughter but cannot be reliably detected at meat inspection.
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| 2. |
- Jonare, Liv, et al.
(författare)
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Questionnaire study suggests grave consequences of infectious laryngotracheitis, infectious coryza and mycoplasmosis in small chicken flocks
- 2023
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Ingår i: Acta Veterinaria Scandinavica. - 0044-605X .- 1751-0147. ; 65
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundA growing number of people in western countries keep small chicken flocks. In Sweden, respiratory disease is a common necropsy finding in chickens from such flocks. A respiratory real-time polymerase chain reaction (PCR) panel was applied to detect infectious laryngotracheitis virus (ILTV), Avibacterium paragallinarum (A. paragallinarum) and Mycoplasma gallisepticum (M. gallisepticum) in chickens from small flocks which underwent necropsy in 2017-2019 and had respiratory lesions. Owners (N = 100) of PCR-positive flocks were invited to reply to a web-based questionnaire about husbandry, outbreak characteristics and management.ResultsResponse rate was 61.0%. The flocks were from 18 out of Sweden's 21 counties indicating that respiratory infections in small chicken flocks are geographically widespread in Sweden. Among participating flocks, 77.0% were coinfected by 2-3 pathogens; 91.8% tested positive for A. paragallinarum, 57.4% for M. gallisepticum and 50.8% for ILTV. Larger flock size and mixed-species flock structure were associated with PCR detection of M. gallisepticum (P = 0.00 and P = 0.02, respectively). Up to 50% mortality was reported by 63.9% of respondents. Euthanasia of some chickens was carried out in 86.9% of the flocks as a result of the outbreaks. Full clinical recovery was reported by 39.3% of owners suggesting chronic infection is a major challenge in infected flocks. Live birds had been introduced in many flocks prior to outbreaks, which suggested these as an important source of infection. Following the outbreaks, 36.1% replaced their flocks with new birds and 9.8% ceased keeping chickens.ConclusionsThis study highlights the severity of respiratory outbreaks in small non-commercial chicken flocks and points to the need for more research and veterinary assistance to prevent and manage respiratory infections in small chicken flocks.
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