Detection of cilia-associated respiratory (CAR) bacillus in nasal-swab specimens from infected rats by use of polymerase chain reaction
Franklin, C.L.; Pletz, J.D.; Riley, L.K.; Livingston, B.A.; Hook, R.R.; Besch-Williford, C.L.
Laboratory Animal Science 49(1): 114-117
1999
ISSN/ISBN: 0023-6764 PMID: 10090107 Document Number: 499156
Thirty-nine 3-week-old rats from a colony that was naturally infected with the R3 isolate of CAR bacillus were anaesthetized and nasal swab specimens were collected for PCR analysis. After collection of these specimens, 8 rats were killed and tissue samples were collected for PCR analysis (nasal-swab and trachea biopsy specimens) and histological preparation (trachea and left lung lobe biopsy specimens). Nasal swabs were taken again and groups of 7-8 rats were killed at 5, 7, 9 and 11 weeks of age. The CAR bacillus DNA was detected on nasal-swab specimens from 54% of 3-week-old rats, 94% of 5-week-old rats, 96% of 7-week-old rats and 100% of 9- and 11-week-old rats. With the exception of one 3-week-old rat, CAR bacillus DNA was detected from clinical nasal-swab specimens of all rats that were positive by PCR analysis of PM samples. One 3-week-old rat and one 5-week-old rat had positive results of PCR analysis of clinical nasal-swab and tracheal specimens and by histological examination of the lung or trachea, but had negative results of PCR testing of PM nasal-swab specimens. The PCR method was superior to histological examination for detecting CAR bacillus colonization, especially in young rats. It is concluded that nasal-swab specimens are an excellent sample for CAR bacillus PCR diagnostic testing.