title: Streptococcus gallolyticus infection in colorectal cancer and association with biological and clinical factors.
abstract: There is an unambiguous association of Streptococcus gallolyticus infection with colorectal cancer, although there is limited information about epidemiology or interaction between molecular and environmental factors. We performed an original quantitative analysis of S. gallolyticus in unselected colorectal cancer patients (n = 190) and their association with clinical, pathological tumor molecular profiles (microsatellite instability, hypermethylator phenotype and chromosomal instability pathways), and other biological factors in colorectal tumor and normal tissues (cytomegalovirus and Epstein-Barr virus infection). We developed a new quantitative method to assess bacterial load. Analytical validation was reached with a very high sensitivity and specificity. Our results showed a 3.2% prevalence of S. gallolyticus infection in our unselected cohort of colorectal cancer cases (6/190). The average S. gallolyticus copy number was 7,018 (range 44-34,585). No previous reports relating to S. gallolyticus infection have been published for unselected cohorts of patients. Finally, and despite a low prevalence of S. gallolyticus in this study, we were able to define a specific association with tumor tissue (p = 0.03) and with coinfection with Epstein-Barr virus (p = 0.042; OR: 9.49; 95% IC: 1.1-82.9). The prevalence data provided will be very useful in the design of future studies, and will make it possible to estimate the sample size needed to assess precise objectives. In conclusion, our results show a low prevalence of S. gallolyticus infection in unselected colorectal cancer patients and an association of positive S. gallolyticus infection with tumor tissue and Epstein-Barr virus coinfection. Further studies will be needed to definitively assess the prevalence of S. gallolyticus in colorectal cancer and the associated clinicopathological and molecular profiles.
authors.affiliation: Microbiology Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Andres-Franch
authors.affiliation: Microbiology Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Galiana
authors.affiliation: Microbiology Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Sanchez-Hellin
authors.affiliation: Biopathology Dept., Hospital Provincial de Castellón, Castellón, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Ochoa
authors.affiliation: Research Lab, Hospital General Universitario de Alicante, Alicante, Spain.|Instituto de Investigación Sanitaria y Biómedica de Alicante (ISABIAL)-FISABIO, Alicante, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Hernandez-Illan
authors.affiliation: Microbiology Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Lopez-Garcia
authors.affiliation: Instituto de Investigación Sanitaria y Biómedica de Alicante (ISABIAL)-FISABIO, Alicante, Spain.|Molecular Genetics Unit, Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Adela
authors.initials: A
authors.lastname: Castillejo
authors.affiliation: Instituto de Investigación Sanitaria y Biómedica de Alicante (ISABIAL)-FISABIO, Alicante, Spain.|Molecular Genetics Unit, Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Castillejo
authors.affiliation: Instituto de Investigación Sanitaria y Biómedica de Alicante (ISABIAL)-FISABIO, Alicante, Spain.|Molecular Genetics Unit, Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Victor Manuel
authors.initials: VM
authors.lastname: Barbera
authors.affiliation: Microbiology Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Josefa
authors.initials: J
authors.lastname: Garcia-Dura
authors.affiliation: Preventive Medicine Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Gomez-Romero
authors.affiliation: Microbiology Dept., Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Gloria
authors.initials: G
authors.lastname: Royo
authors.affiliation: Instituto de Investigación Sanitaria y Biómedica de Alicante (ISABIAL)-FISABIO, Alicante, Spain.|Molecular Genetics Unit, Hospital General Universitario de Elche, Elche, Spain.
authors.forename: Jose Luis
authors.initials: JL
authors.lastname: Soto
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003106:Colon / Q000382:microbiology / Q000473:pathology; D015179:Colorectal Neoplasms / Q000235:genetics / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D013290:Streptococcal Infections / Q000150:complications* / Q000235:genetics; D000070099:Streptococcus gallolyticus / Q000502:physiology*