|Awad, Amal - Mansoura University|
|Ramadan, Hazem - Mansoura University|
Submitted to: American Society for Microbiology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2019
Publication Date: N/A
Interpretive Summary: n/a
Technical Abstract: Background: Campylobacter jejuni is the leading etiologic pathogen that causes human acute bacterial gastroenteritis worldwide. Risk assessment studies show the source of human C. jejuni infection has been linked to consumption and handling of unsanitary poultry products. Since its fastidious growth, biochemical requirements and genetic diversity, classification of C. jejuni by traditional methods is problematic. Due to the progress in sequencing technology and bioinformatic algorithms, various molecular typings of their genomes have been used, such as multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). In the present study, we applied these two methods to elucidate the genetic diversity of C.jejuni isolates from US poultry farm and processing operations. Methods: C. jejuni (n = 100) isolates from various poultry sources from four different regions in the United States. Genomic DNA of C. jejuni isolates were extracted from cultures grown in Müeller-Hinton agar at 42 oC for 48 hours using a commercial kit. PCR primers and conditions for MLST amplification of seven housekeeping genes were described previously. The amplicons were purified with a commercial kit, and the purified DNA fragments were sent to the USDA ARS Genomics and Bioinformatics Research Unit for sequencing, where the Sanger dideoxy sequencing method was performed. The sequences were compared with those deposited in the MLST database. PFGE was performed following the standard protocol recommended by CDC for Campylobacter spp. Results: Among the 100 C. jejuni isolates 13 different sequence types (STs) were identified. Theses STs were grouped into 7 previously described clonal complexes (CCs). Nine isolates assigned to ST-940 did not match any defined CC in the MLST database. Clonal complexes (CC353, CC48 and CC21) were dominated among the seven assigned CCs in isolates tested. On the ST-level, the most frequent sequence types exist were ST-353, ST-48 and ST-50, representing 66% (66/100) of the total screened isolates. By PFGE, twenty–two smaI profile were identified among the C. jejuni isolates, and six groups closely related isolates have been assigned (S1-S6). Conclusion: This study has shown the diversity of C. jejuni isolates in US poultry sources. Most of the C. jejuni sequence types detected in the present study have been associated with human illness, which supports the significant role of poultry as a major source for human Campylobacter infections.