Original Contribution
The American Journal of Gastroenterology (2005) 100, 1529–1536; doi:10.1111/j.1572-0241.2005.41415.x
Detection and Isolation of Mycobacterium avium Subspecies paratuberculosis from Intestinal Mucosal Biopsies of Patients with and without Crohn's Disease in Sardinia
Leonardo A Sechi PhD1, Antonio M Scanu MD2, Paola Molicotti PhD1, Sara Cannas PhD1, Manuela Mura PhD1, Giuseppe Dettori MD2, Giovanni Fadda MD3 and Stefania Zanetti PhD1
- 1Dipartimento di Scienze Biomediche, Sezione di Microbiologia Sperimentale e Clinica, Università degli studi di Sassari, Sassari;
- 2Clinica Chirurgica, Università degli studi di Sassari, Sassari;
- 3Istituto di Microbiologia, Facoltà di Medicina e Chirurgia "Agostino Gemelli," Università Cattolica del Sacro Cuore, Roma, Italy
Correspondence: Leonardo A Sechi, Dipartimento di Scienze Biomediche, Sezione di Microbiologia Sperimentale e Clinica, Università degli studi di Sassari, Viale S. Pietro 43/B, 07100 Sassari, Italy
Received 30 August 2004; Revised 0000; Accepted 7 January 2005.
Abstract
OBJECTIVES:
Sardinia is an island community of 1.6 million people. There are also about 3.5 million sheep and one hundred thousand cattle in which Johne's disease and Mycobacterium avium subspecies paratuberculosis infection are endemic. The present study was designed to determine what proportion of people in Sardinia attending for ileocolonoscopy with or without Crohn's disease were infected with this pathogen.
METHODS:
Mycobacterium avium subspecies paratuberculosis was detected by IS900 PCR on DNA extracts of fresh intestinal mucosal biopsies as well as by isolation in culture using supplemented MGIT media followed by PCR with amplicon sequencing.
RESULTS:
Twenty five patients (83.3%) with Crohn's disease and 3 control patients (10.3%) were IS900 PCR positive (p = 0.000001; Odds ratio 43.3). Mycobacterium avium subspecies paratuberculosis grew in cultures from 19 Crohn's patients (63.3%) and from 3 control patients (10.3%) (p = 0.00001; Odds ratio 14.9). All patients positive by culture had previously been positive by PCR. Mycobacterium avium subspecies paratuberculosis first appeared in the liquid cultures in a Ziehl Neelsen (ZN) staining negative form and partially reverted through a rhodamine-auramine positive staining form to the classical ZN positive form. This resulted in a stable mixed culture of all 3 forms illustrating the phenotypic versatility of these complex chronic enteric pathogens.
CONCLUSIONS:
Mycobacterium avium subspecies paratuberculosis was detected in the majority of Sardinian Crohn's disease patients. The finding of the organism colonizing a proportion of people without Crohn's disease is consistent with what occurs in other conditions caused by a primary bacterial pathogen in susceptible hosts.
