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Three commercially available assays, designed to specifically detect the presence of Mycobacterium aviumsubsp. paratuberculosis(MAP) in fecal samples by IS900-PCR, were compared with a conventional culture method. Fecal samples from 100 dairy cows were tested. Fifty-four (67.5%) of 80 culture-positive samples were positive for an assay that detects MAP DNA by dot spot hybridization of polymerase chain reaction products (kit A), 48 (60%) were positive by an assay using ethidium bromide staining for agar gel visualization of amplification products (kit B), and 49 (61.3%) were positive by an assay in which amplified products are detected by a colorimetric detection system (kit C). Relative sensitivity of all tests increased in proportion to the presence of MAP in fecal samples. Specificity was 100% based on results from 20 culture-negative samples from an MAP-free herd.

Lactobacillus gasseri4B2 is a human isolate characterised by a strong autoaggregating phenotype mediated by APF (aggregation‐promoting factor), a secreted protein. Two primer pairs were developed for simultaneous amplification of a specific fragment of the APF gene and a highly conserved region of the 16S rRNA gene. The specificity of this protocol was checked in DNA samples isolated from single and mixed cultures of Lactobacillus. The same amplification protocol was successfully used directly adding whole bacterial cells to PCR reaction tubes. The suitability of this method for in vivo studies was investigated through feeding L. gasseri4B2 to mice and analysing colony forming units obtained by plating faecal samples on selective medium. The methodology allows a fast and reliable identification of the target strain without any DNA extraction procedure.

Lactobacillus gasseri 4B2 is a human isolate characterised by a strong autoaggregating phenotype mediated by APF (aggregation-promoting factor), a secreted protein. Two primer pairs were developed for simultaneous amplification of a specific fragment of the APF gene and a highly conserved region of the 16S rRNA gene. The specificity of this protocol was checked in DNA samples isolated from single and mixed cultures of Lactobacillus. The same amplification protocol was successfully used directly adding whole bacterial cells to PCR reaction tubes. The suitability of this method for in vivo studies was investigated through feeding L. gasseri 4B2 to mice and analysing colony forming units obtained by plating faecal samples on selective medium. The methodology allows a fast and reliable identification of the target strain without any DNA extraction procedure.