Protocol for a Diagnostic Accuracy Study of Polymerase Chain Reaction for Detecting Group B &lt;i&gt;Streptococcus&lt;/i&gt; Colonisation in Early Labour or with Spontaneous Ruptured Membranes

Molecular techniques are increasingly being applied to stained cytology slides for the diagnosis of neoplastic and infectious diseases. Such techniques for the identification of fungi from stained cytology slides have not yet been evaluated. This study aimed to assess the diagnostic accuracy of direct (without nucleic acid isolation) panfungal polymerase chain reaction (PCR) followed by sequencing for identification of fungi and oomycetes on stained cytology slides from dogs, cats, horses, and other species. Thirty-six cases were identified with cytologically identifiable fungi/oomycetes and concurrent identification via fungal culture or immunoassay. Twenty-nine controls were identified with no cytologically or histologically visible organisms and a concurrent negative fungal culture. Direct PCR targeting the internal transcribed spacer region followed by sequencing was performed on one cytology slide from each case and control, and the sensitivity and specificity of the assay were calculated. The sensitivity of the panfungal PCR assay performed on stained cytology slides was 67% overall, 73% excluding cases with oomycetes, and 86% when considering only slides with abundant fungi. The specificity was 62%, which was attributed to amplification of fungal DNA from control slides with no visible fungus and negative culture results. Direct panfungal PCR is capable of providing genus- or species-level identification of fungi from stained cytology slides. Given the potential of panfungal PCR to amplify contaminant fungal DNA, this assay should be performed on slides with visible fungi and interpreted in conjunction with morphologic assessment by a clinical pathologist.

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Comparison of Three Rapid Commercial Canine Parvovirus Antigen Detection Tests with Electron Microscopy and Polymerase Chain Reaction

Journal of Veterinary Diagnostic Investigation ◽

10.1177/104063870902100306 ◽

2009 ◽

Vol 21 (3) ◽

pp. 344-345 ◽

Cited By ~ 35

Author(s):

Silke Schmitz ◽

Christina Coenen ◽

König Matthias ◽

Thiel Heinz-Jürgen ◽

Reto Neiger

Keyword(s):

Electron Microscopy ◽

Polymerase Chain Reaction ◽

Chronic Diarrhea ◽

Gastrointestinal Disease ◽

Clinical Signs ◽

Canine Parvovirus ◽

Chain Reaction ◽

Group A ◽

Polymerase Chain ◽

Group B

Different antibody-based tests for rapid detection of Canine parvovirus antigens in feces are commercially available, allowing quick diagnosis in a clinical setting. However, the diagnostic accuracy of these tests compared with standard methods has not been evaluated so far. In the current study, 3 commercial tests were compared with immune-electron microscopy (IEM) and polymerase chain reaction (PCR). Dogs were divided into 3 groups: group A, samples from dogs with acute hemorrhagic diarrhea ( n = 50); group B, dogs with chronic diarrhea ( n = 10); and group C, dogs with no evidence of gastrointestinal disease ( n = 40). Specificity of all 3 commercial tests versus PCR and IEM was good to excellent (92.2–100%). Sensitivity, in contrast, was poor: 15.8–26.3% versus PCR and 50–60% versus IEM. In group A, 10 dogs were positive by IEM and 24 dogs were positive by PCR. Positive PCR results were also obtained from animals in control groups (group B, 1 dog; group C, 5 dogs). No dog in group B or C was positive by IEM. In conclusion, the rapid tests are useful to diagnose canine parvoviral enteritis, but they do not rule out parvovirus infection in an animal with typical clinical signs. In addition, a small percentage of healthy dogs and dogs with chronic diarrhea showed positive PCR results; this may be due to asymptomatic/persistent infection or intestinal passage of virus. The significance of this finding remains unclear.

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