Evaluation of indirect and avidin-biotin enzyme linked immunosorbent assays for detection of anti-listeriolysin O antibodies in bovine milk samples.
Listeria monocytogenes is a foodborne pathogen that causes a wide spectrum of diseases in humans and animals. Enzyme linked immunosorbent assays (ELISA) [indirect and avidin-biotin (A-B)] for detecting L. monocytogenes antibodies in bovine milk samples (n = 2060) were standardized and evaluated by comparison with bacteriological examination. The tests were standardized by checker board titration. Highly purified listeriolysin O (LLO) was used as an antigen. Receiver operating characteristic (ROC) analysis was performed to decide the cut-off values. The ROC analysis revealed the sensitivities of indirect and A-B ELISA as 100% and specificities as 97.1 and 99.9% respectively. Listeria monocytogenes was isolated from 105 (5.1%) milk samples collected from 52 farms. Anti-LLO IgG antibodies were detected from 137 and 112 milk samples when tested by indirect and A-B ELISA respectively. Of the 52 farms screened, 28 (53.8%) yielded one or more isolates of L. monocytogenes and 33 (63.5%) of the farms had one or more animals simultaneously positive by one or both the assays for anti-LLO antibodies.
Kalorey
D R
DR
Department of Veterinary Microbiology, Nagpur Veterinary College, Maharashtra Animal and Fishery Sciences University, Nagpur 440 006, India.
Kurkure
N V
NV
Warke
S R
SR
Barbuddhe
S B
SB
D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis*; D001360:Avidin; D001710:Biotin; D002417:Cattle; D003612:Dairying; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D005516:Food Microbiology; D006801:Humans; D007194:India; D008089:Listeria monocytogenes / Q000276:immunology / Q000302:isolation & purification*; D008892:Milk / Q000382:microbiology*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012680:Sensitivity and Specificity
D000907:Antibodies, Bacterial; D001360:Avidin; D001710:Biotin