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Molecular survey of bacterial communities associated with bacterial chondronecrosis with osteomyelitis (BCO) in broilers.

Jiang T, Mandal RK, Wideman RF, Khatiwara A, Pevzner I, Min Kwon Y - PLoS ONE (2015)

Bottom Line: Relatively little is known about the microbial communities associated with BCO.Rarefaction analysis demonstrated the general tendency that increased severities of BCO lesions were associated with reduced species diversity in both femoral and tibial samples when compared to macroscopically normal samples.These observations suggest that certain bacterial subgroups are preferentially selected in association with the development of BCO lesions.

View Article: PubMed Central - PubMed

Affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, Arkansas, United States of America.

ABSTRACT
Bacterial chondronecrosis with osteomyelitis (BCO) is recognized as an important cause of lameness in commercial broiler chickens (meat-type chickens). Relatively little is known about the microbial communities associated with BCO. This study was conducted to increase our understanding of the microbial factors associated with BCO using a culture-independent approach. Using Illumina sequencing of the hyper-variable region V6 in the 16S rRNA gene, we characterized the bacterial communities in 97 femoral or tibial heads from normal and lame broilers carefully selected to represent diverse variations in age, line, lesion type, floor type, clinical status and bone type. Our in-depth survey based on 14 million assembled sequence reads revealed that complex bacterial communities exist in all samples, including macroscopically normal bones from clinically healthy birds. Overall, Proteobacteria (mean 90.9%) comprised the most common phylum, followed by Firmicutes (6.1%) and Actinobacteria (2.6%), accounting for more than 99% of all reads. Statistical analyses demonstrated that there are differences in bacterial communities in different types of bones (femur vs. tibia), lesion types (macroscopically normal femora or tibiae vs. those with pathognomonic BCO lesions), and among individual birds. This analysis also showed that BCO samples overrepresented genera Staphylococcus, whose species have been frequently isolated in BCO samples in previous studies. Rarefaction analysis demonstrated the general tendency that increased severities of BCO lesions were associated with reduced species diversity in both femoral and tibial samples when compared to macroscopically normal samples. These observations suggest that certain bacterial subgroups are preferentially selected in association with the development of BCO lesions. Understanding the microbial species associated with BCO will identify opportunities for understanding and modulating the pathogenesis of this form of lameness in broilers.

No MeSH data available.


Related in: MedlinePlus

The incidence of lameness in two lines (line B and line D) developed on wire flooring and on wood-shavings litter flooring from days 14 through 49.
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pone.0124403.g003: The incidence of lameness in two lines (line B and line D) developed on wire flooring and on wood-shavings litter flooring from days 14 through 49.

Mentions: BCO is recognized as an important cause of lameness in rapidly growing broilers. BCO appears to be initiated by osteochondrotic micro-trauma to poorly mineralized columns of cartilage cells in the metaphyses and proximal growth plates of the leg bones, followed by colonization by hematogenously distributed opportunistic bacteria [4,5]. Bacteria that translocate into the chick's circulation can spread hematogenously and exit the bloodstream through the fenestrated capillaries supplying the growth plate. Once the osteochondrotic clefts and micro-fractures become infected, leukocytes migrate into the infected area, and, in their attempt to engulf the infectious organisms, release enzymes that lyse the bone. Pus spreads into the bone's blood vessels, impairing their flow, and areas of devitalized infected bone, known as sequestra, form the basis of a chronic infection. Terminal BCO presents as necrotic degeneration and bacterial infection primarily within the proximal head of the femora and tibiae, as well as in the growth plates of the flexible thoracic vertebrae [2,5]. Rearing broilers on wire flooring facilitates our ability to investigate the pathogenesis of BCO by consistently triggering substantially higher incidences than typically observed when broilers are reared on wood-shavings litter flooring [4]. In the present study significantly more broilers developed BCO lameness on wire flooring than on litter (27.2% vs. 4.4%, respectively; P = 0.002, z-test). More broilers from Line B developed lameness on wire flooring than broilers from Line D (33.8% vs. 20.6%, respectively; P = 0.011, z-test), whereas the lameness incidences for the two lines did not differ on litter flooring (7.5% vs. 1.3%, respectively; P = 0.126, z-test) (Fig 3).


Molecular survey of bacterial communities associated with bacterial chondronecrosis with osteomyelitis (BCO) in broilers.

Jiang T, Mandal RK, Wideman RF, Khatiwara A, Pevzner I, Min Kwon Y - PLoS ONE (2015)

The incidence of lameness in two lines (line B and line D) developed on wire flooring and on wood-shavings litter flooring from days 14 through 49.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4400152&req=5

pone.0124403.g003: The incidence of lameness in two lines (line B and line D) developed on wire flooring and on wood-shavings litter flooring from days 14 through 49.
Mentions: BCO is recognized as an important cause of lameness in rapidly growing broilers. BCO appears to be initiated by osteochondrotic micro-trauma to poorly mineralized columns of cartilage cells in the metaphyses and proximal growth plates of the leg bones, followed by colonization by hematogenously distributed opportunistic bacteria [4,5]. Bacteria that translocate into the chick's circulation can spread hematogenously and exit the bloodstream through the fenestrated capillaries supplying the growth plate. Once the osteochondrotic clefts and micro-fractures become infected, leukocytes migrate into the infected area, and, in their attempt to engulf the infectious organisms, release enzymes that lyse the bone. Pus spreads into the bone's blood vessels, impairing their flow, and areas of devitalized infected bone, known as sequestra, form the basis of a chronic infection. Terminal BCO presents as necrotic degeneration and bacterial infection primarily within the proximal head of the femora and tibiae, as well as in the growth plates of the flexible thoracic vertebrae [2,5]. Rearing broilers on wire flooring facilitates our ability to investigate the pathogenesis of BCO by consistently triggering substantially higher incidences than typically observed when broilers are reared on wood-shavings litter flooring [4]. In the present study significantly more broilers developed BCO lameness on wire flooring than on litter (27.2% vs. 4.4%, respectively; P = 0.002, z-test). More broilers from Line B developed lameness on wire flooring than broilers from Line D (33.8% vs. 20.6%, respectively; P = 0.011, z-test), whereas the lameness incidences for the two lines did not differ on litter flooring (7.5% vs. 1.3%, respectively; P = 0.126, z-test) (Fig 3).

Bottom Line: Relatively little is known about the microbial communities associated with BCO.Rarefaction analysis demonstrated the general tendency that increased severities of BCO lesions were associated with reduced species diversity in both femoral and tibial samples when compared to macroscopically normal samples.These observations suggest that certain bacterial subgroups are preferentially selected in association with the development of BCO lesions.

View Article: PubMed Central - PubMed

Affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, Arkansas, United States of America.

ABSTRACT
Bacterial chondronecrosis with osteomyelitis (BCO) is recognized as an important cause of lameness in commercial broiler chickens (meat-type chickens). Relatively little is known about the microbial communities associated with BCO. This study was conducted to increase our understanding of the microbial factors associated with BCO using a culture-independent approach. Using Illumina sequencing of the hyper-variable region V6 in the 16S rRNA gene, we characterized the bacterial communities in 97 femoral or tibial heads from normal and lame broilers carefully selected to represent diverse variations in age, line, lesion type, floor type, clinical status and bone type. Our in-depth survey based on 14 million assembled sequence reads revealed that complex bacterial communities exist in all samples, including macroscopically normal bones from clinically healthy birds. Overall, Proteobacteria (mean 90.9%) comprised the most common phylum, followed by Firmicutes (6.1%) and Actinobacteria (2.6%), accounting for more than 99% of all reads. Statistical analyses demonstrated that there are differences in bacterial communities in different types of bones (femur vs. tibia), lesion types (macroscopically normal femora or tibiae vs. those with pathognomonic BCO lesions), and among individual birds. This analysis also showed that BCO samples overrepresented genera Staphylococcus, whose species have been frequently isolated in BCO samples in previous studies. Rarefaction analysis demonstrated the general tendency that increased severities of BCO lesions were associated with reduced species diversity in both femoral and tibial samples when compared to macroscopically normal samples. These observations suggest that certain bacterial subgroups are preferentially selected in association with the development of BCO lesions. Understanding the microbial species associated with BCO will identify opportunities for understanding and modulating the pathogenesis of this form of lameness in broilers.

No MeSH data available.


Related in: MedlinePlus