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Community analysis of bacteria colonizing intestinal tissue of neonates with necrotizing enterocolitis.

Smith B, Bodé S, Petersen BL, Jensen TK, Pipper C, Kloppenborg J, Boyé M, Krogfelt KA, Mølbak L - BMC Microbiol. (2011)

Bottom Line: A 16S rRNA gene sequence tag similar to Ralstonia species was detected in most of the neonatal tissues and members of this genus have been reported to be opportunistic pathogens but their role in NEC has still to be clarified.However there was a significant correlation between the presence of C. butyricum & C. parputrificum and histological pneumatosis intestinalis.Finally this study emphasizes the possibility to examine the microbial composition directly on excised human tissues to avoid biases from faecal samples or culturing.

View Article: PubMed Central - HTML - PubMed

Affiliation: Statens Serum Institut, Artillerivej 5, 2300 Kbh. S, Denmark.

ABSTRACT

Background: Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in newborn neonates. Bacteria are believed to be important in the pathogenesis of NEC but bacterial characterization has only been done on human faecal samples and experimental animal studies. The aim of this study was to investigate the microbial composition and the relative number of bacteria in inflamed intestinal tissue surgically removed from neonates diagnosed with NEC (n=24). The bacterial populations in the specimens were characterized by laser capture microdissection and subsequent sequencing combined with fluorescent in situ hybridization (FISH), using bacterial rRNA-targeting oligonucleotide probes.

Results: Bacteria were detected in 22 of the 24 specimens, 71% had moderate to high densities of bacteria. The phyla detected by 16S rRNA gene sequencing were: Proteobacteria (49.0%), Firmicutes (30.4%), Actinobacteria (17.1%) and Bacteroidetes (3.6%). A major detected class of the phylum Proteobacteria belonged to δ-proteobacteria. Surprisingly, Clostridium species were only detected in 4 of the specimens by FISH, but two of these specimens exhibited histological pneumatosis intestinalis and both specimens had a moderate to a high density of C. butyricum and C. parputrificum detected by using species specific FISH probes. A 16S rRNA gene sequence tag similar to Ralstonia species was detected in most of the neonatal tissues and members of this genus have been reported to be opportunistic pathogens but their role in NEC has still to be clarified.

Conclusion: In this study, in situ identification and community analysis of bacteria found in tissue specimens from neonates with NEC, were analysed for the first time. Although a large variability of bacteria was found in most of the analyzed specimens, no single or combination of known potential pathogenic bacteria species was dominating the samples suggestive NEC as non-infectious syndrome. However there was a significant correlation between the presence of C. butyricum & C. parputrificum and histological pneumatosis intestinalis. Finally this study emphasizes the possibility to examine the microbial composition directly on excised human tissues to avoid biases from faecal samples or culturing.

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Phylogenetic relationship among Ralstonia detected in the tissue samples from the NEC infants. R. detusculanense, R. pickettii and R. insidiosa did all have more than 99% similarity with the matched Ralstonia tag from the 16S rRNA gene clone library from this study. The bacteria names and the accession numbers are shown.
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Figure 4: Phylogenetic relationship among Ralstonia detected in the tissue samples from the NEC infants. R. detusculanense, R. pickettii and R. insidiosa did all have more than 99% similarity with the matched Ralstonia tag from the 16S rRNA gene clone library from this study. The bacteria names and the accession numbers are shown.

Mentions: The bacteria associated with the tissue in the individually neonates have the potential to reveal bacterial pathogens related to the pathogenesis of NEC. In the δ-proteobacteria group Escherichia/Shigella genera dominated with a frequency of 45% out of all δ-proteobacteria and were present in 5 of the 8 neonates with an average frequency of 24% (±36%). The Enterobacteriaceae group consisted of virtually one tag but it was similar to genera of Citrobacter, Enterobacter (Klebsiella) and Erwinia and was detected in 4 of the neonates. The taxonomic class Clostridia contained 10 different tags belonging to a variety of different genera (Table 4), the two most prominent being Clostridium and Anaerococcus detected in four and three neonates, respectively. A tag matching the potential pathogen Finegoldia was found twice in two different neonates. One of the specimen characterised histologically exhibiting pneumatosis intestinalis was also observed to include the genus Clostridium. The most prevalent tag belonged to Ralstonia being present in 7 out of 8 neonates, with an average of 9% (±5%). R. detusculanense, R. pickettii and R. insidiosa were revealed with more than 99% similarity (Figure 4).


Community analysis of bacteria colonizing intestinal tissue of neonates with necrotizing enterocolitis.

Smith B, Bodé S, Petersen BL, Jensen TK, Pipper C, Kloppenborg J, Boyé M, Krogfelt KA, Mølbak L - BMC Microbiol. (2011)

Phylogenetic relationship among Ralstonia detected in the tissue samples from the NEC infants. R. detusculanense, R. pickettii and R. insidiosa did all have more than 99% similarity with the matched Ralstonia tag from the 16S rRNA gene clone library from this study. The bacteria names and the accession numbers are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3094198&req=5

Figure 4: Phylogenetic relationship among Ralstonia detected in the tissue samples from the NEC infants. R. detusculanense, R. pickettii and R. insidiosa did all have more than 99% similarity with the matched Ralstonia tag from the 16S rRNA gene clone library from this study. The bacteria names and the accession numbers are shown.
Mentions: The bacteria associated with the tissue in the individually neonates have the potential to reveal bacterial pathogens related to the pathogenesis of NEC. In the δ-proteobacteria group Escherichia/Shigella genera dominated with a frequency of 45% out of all δ-proteobacteria and were present in 5 of the 8 neonates with an average frequency of 24% (±36%). The Enterobacteriaceae group consisted of virtually one tag but it was similar to genera of Citrobacter, Enterobacter (Klebsiella) and Erwinia and was detected in 4 of the neonates. The taxonomic class Clostridia contained 10 different tags belonging to a variety of different genera (Table 4), the two most prominent being Clostridium and Anaerococcus detected in four and three neonates, respectively. A tag matching the potential pathogen Finegoldia was found twice in two different neonates. One of the specimen characterised histologically exhibiting pneumatosis intestinalis was also observed to include the genus Clostridium. The most prevalent tag belonged to Ralstonia being present in 7 out of 8 neonates, with an average of 9% (±5%). R. detusculanense, R. pickettii and R. insidiosa were revealed with more than 99% similarity (Figure 4).

Bottom Line: A 16S rRNA gene sequence tag similar to Ralstonia species was detected in most of the neonatal tissues and members of this genus have been reported to be opportunistic pathogens but their role in NEC has still to be clarified.However there was a significant correlation between the presence of C. butyricum & C. parputrificum and histological pneumatosis intestinalis.Finally this study emphasizes the possibility to examine the microbial composition directly on excised human tissues to avoid biases from faecal samples or culturing.

View Article: PubMed Central - HTML - PubMed

Affiliation: Statens Serum Institut, Artillerivej 5, 2300 Kbh. S, Denmark.

ABSTRACT

Background: Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in newborn neonates. Bacteria are believed to be important in the pathogenesis of NEC but bacterial characterization has only been done on human faecal samples and experimental animal studies. The aim of this study was to investigate the microbial composition and the relative number of bacteria in inflamed intestinal tissue surgically removed from neonates diagnosed with NEC (n=24). The bacterial populations in the specimens were characterized by laser capture microdissection and subsequent sequencing combined with fluorescent in situ hybridization (FISH), using bacterial rRNA-targeting oligonucleotide probes.

Results: Bacteria were detected in 22 of the 24 specimens, 71% had moderate to high densities of bacteria. The phyla detected by 16S rRNA gene sequencing were: Proteobacteria (49.0%), Firmicutes (30.4%), Actinobacteria (17.1%) and Bacteroidetes (3.6%). A major detected class of the phylum Proteobacteria belonged to δ-proteobacteria. Surprisingly, Clostridium species were only detected in 4 of the specimens by FISH, but two of these specimens exhibited histological pneumatosis intestinalis and both specimens had a moderate to a high density of C. butyricum and C. parputrificum detected by using species specific FISH probes. A 16S rRNA gene sequence tag similar to Ralstonia species was detected in most of the neonatal tissues and members of this genus have been reported to be opportunistic pathogens but their role in NEC has still to be clarified.

Conclusion: In this study, in situ identification and community analysis of bacteria found in tissue specimens from neonates with NEC, were analysed for the first time. Although a large variability of bacteria was found in most of the analyzed specimens, no single or combination of known potential pathogenic bacteria species was dominating the samples suggestive NEC as non-infectious syndrome. However there was a significant correlation between the presence of C. butyricum & C. parputrificum and histological pneumatosis intestinalis. Finally this study emphasizes the possibility to examine the microbial composition directly on excised human tissues to avoid biases from faecal samples or culturing.

Show MeSH
Related in: MedlinePlus