Author/Editor		Forgetta, Vincenzo; Rupnik, Maja
Title		Fourteen-genome comparison identifies DNA markers for severe-disease-associated strains of Clostridium difficile
Type		članek
Vol. and No.		Letnik 49, št. 6
Publication year		2011
Volume		str. 2230-2238
ISSN		0095-1137 - Journal of clinical microbiology
Language		eng
Abstract		Clostridium difficile is a common cause of infectious diarrhea in hospitalizedpatients. A severe and increased incidence of C. difficile infection (CDI) is associated predominantly with the NAP1 strain; however, theexistence of other severe-disease-associated (SDA) strains and the extensive genetic diversity across C. difficile complicate reliable detection and diagnosis. Comparative genome analysis of 14 sequenced genomes, including those of a subset of NAP1 isolates, allowed the assessment of genetic diversity within and between strain types to identify DNA markers that are associated with severe disease. Comparative genome analysis of 14 isolates, including five publicly available strains, revealed that C. difficile has a core genome of 3.4 Mb, comprising 3,000 genes. Analysis of the core genome identified candidate DNA markers that were subsequently evaluated using a multistrain panel of 177 isolates, representing more than 50 pulsovars and 8 toxinotypes. A subset of 117 isolates from the panel had associated patient data that allowed assessment of an association between the DNA markers and severe CDI. We identified 20 candidate DNA markers for species-wide detection and 10,683 single nucleotide polymorphisms (SNPs) associated with the predominant SDA strain (NAP1). A species-wide detection candidate marker, the sspA gene, was found to be the same across 177 sequenced isolates and lacked significant similarity to those of other species. Candidate SNPs in genes CD1269 and CD1265 were found to associate more closely with disease severity than currently used diagnostic markers, as they were also present in the toxinA-negative and B-positive (A-B+) strain types. The genetic markers identified illustrate the potential of comparative genomics for the discovery of diagnostic DNA-based targets that are species specific or associated with multiple SDA strains.
Keywords		Clostridium difficile toksini geni bakterije