title: Intestinal microbiota and species diversity of Campylobacter and Helicobacter spp. in migrating shorebirds in Delaware Bay.
abstract: Using 16S rRNA gene sequencing analysis, we examined the bacterial diversity and the presence of opportunistic bacterial pathogens (i.e., Campylobacter and Helicobacter) in red knot (Calidris canutus; n = 40), ruddy turnstone (Arenaria interpres; n = 35), and semipalmated sandpiper (Calidris pusilla; n = 22) fecal samples collected during a migratory stopover in Delaware Bay. Additionally, we studied the occurrence of Campylobacter spp., enterococci, and waterfowl fecal source markers using quantitative PCR (qPCR) assays. Of 3,889 16S rRNA clone sequences analyzed, the bacterial community was mostly composed of Bacilli (63.5%), Fusobacteria (12.7%), Epsilonproteobacteria (6.5%), and Clostridia (5.8%). When epsilonproteobacterium-specific 23S rRNA gene clone libraries (i.e., 1,414 sequences) were analyzed, the sequences were identified as Campylobacter (82.3%) or Helicobacter (17.7%) spp. Specifically, 38.4%, 10.1%, and 26.0% of clone sequences were identified as C. lari (>99% sequence identity) in ruddy turnstone, red knot, and semipalmated sandpiper clone libraries, respectively. Other pathogenic species of Campylobacter, such as C. jejuni and C. coli, were not detected in excreta of any of the three bird species. Most Helicobacter-like sequences identified were closely related to H. pametensis (>99% sequence identity) and H. anseris (92% sequence identity). qPCR results showed that the occurrence and abundance of Campylobacter spp. was relatively high compared to those of fecal indicator bacteria, such as Enterococcus spp., E. faecalis, and Catellicoccus marimammalium. Overall, the results provide insights into the complexity of the shorebird gut microbial community and suggest that these migratory birds are important reservoirs of pathogenic Campylobacter species.
authors.affiliation: National Risk Management Research Laboratory, U.S. Environmental Protection Agency, Cincinnati, Ohio, USA.
authors.forename: Hodon
authors.initials: H
authors.lastname: Ryu
authors.forename: Kirsten
authors.initials: K
authors.lastname: Grond
authors.forename: Bram
authors.initials: B
authors.lastname: Verheijen
authors.forename: Michael
authors.initials: M
authors.lastname: Elk
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Buehler
authors.forename: Jorge W
authors.initials: JW
authors.lastname: Santo Domingo
mesh_terms: D000818:Animals; D058448:Biota; D002167:Campylobacter / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D046091:Charadriiformes / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D003691:Delaware; D005243:Feces / Q000382:microbiology; D041981:Gastrointestinal Tract / Q000382:microbiology*; D016998:Helicobacter / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010802:Phylogeny; D015995:Prevalence; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S