TY - JOUR

T1 - Detection of Lawsonia intracellularis in Formalin-fixed Porcine Intestinal Tissue Samples

T2 - Comparison of Immunofluorescence and In-situ Hybridization, and Evaluation of the Effects of Controlled Autolysis

AU - Jensen, T. K.

AU - Vigre, H.

PY - 2010/1

Y1 - 2010/1

N2 - Two methods, an immunofluorescence assay (IFA; with a Lawsonia intracellularis-specific monoclonal antibody) and fluorescent in-situ hybridization (FISH; with a specific oligonucleotide probe targeting 16S ribosomal RNA of the bacterium), were compared for their ability to detect L. intracellularis (the cause of porcine proliferative enteritis [PE]) in formalin-fixed samples of intestinal tissue. Of 69 intestinal samples with gross lesions of PE, 63 were positive by both FISH and IFA, but six were positive only by IFA. This indicated that the sensitivity of FISH was 91% that of IFA. However, both methods had a specificity of 100%. Fifty normal porcine intestines were negative by both tests. IFA was much less susceptible than FISH to the effects of autolysis. Thus, three of nine samples from pigs with PE were FISH-negative after being kept at 20°C for 4 days, and seven were FISH negative after 2 weeks; after 4 weeks at this temperature, however, six of the nine samples were still IFA positive. After being kept at 4°C for 12 weeks, the majority of samples (≥66%) were positive by both methods.

AB - Two methods, an immunofluorescence assay (IFA; with a Lawsonia intracellularis-specific monoclonal antibody) and fluorescent in-situ hybridization (FISH; with a specific oligonucleotide probe targeting 16S ribosomal RNA of the bacterium), were compared for their ability to detect L. intracellularis (the cause of porcine proliferative enteritis [PE]) in formalin-fixed samples of intestinal tissue. Of 69 intestinal samples with gross lesions of PE, 63 were positive by both FISH and IFA, but six were positive only by IFA. This indicated that the sensitivity of FISH was 91% that of IFA. However, both methods had a specificity of 100%. Fifty normal porcine intestines were negative by both tests. IFA was much less susceptible than FISH to the effects of autolysis. Thus, three of nine samples from pigs with PE were FISH-negative after being kept at 20°C for 4 days, and seven were FISH negative after 2 weeks; after 4 weeks at this temperature, however, six of the nine samples were still IFA positive. After being kept at 4°C for 12 weeks, the majority of samples (≥66%) were positive by both methods.

KW - bacterial infection

KW - Lawsonia intracellularis

KW - PE diagnosis

KW - pig

KW - proliferative enteropathy (PE)

UR - http://www.scopus.com/inward/record.url?scp=71149120981&partnerID=8YFLogxK

U2 - 10.1016/j.jcpa.2009.04.001

DO - 10.1016/j.jcpa.2009.04.001

M3 - Journal article

C2 - 19909968

AN - SCOPUS:71149120981

VL - 142

SP - 1

EP - 8

JO - Journal of Comparative Pathology

JF - Journal of Comparative Pathology

SN - 0021-9975

IS - 1

ER -