Amplified in situ hybridization with peptide nucleic acid probes for differentiation of Mycobacterium tuberculosis complex and nontuberculous Mycobacterium species on formalin-fixed, paraffin-embedded archival biopsy and autopsy samples.
The aim of this study was to evaluate sensitivity and specificity of in situ hybridization (ISH) using peptide nucleic acid (PNA) probes and tyramide-based amplification for the differentiation between Mycobacterium tuberculosis (MTB) and mycobacteria other than tuberculosis (MOTT) on formalin-fixed, paraffin-embedded tissue samples. We performed ISH simultaneously with both probes on 86 specimens from different organs: 70 obtained at autopsy and 16 by biopsy, all with a histologic evidence of mycobacterial infection confirmed by Ziehl-Neelsen-positive staining. Taking culture as the "gold standard," the sensitivity and the specificity of the MTB probe were 100% (41/41) and 95% (38/40), respectively. In only 2 cases ISH failed to identify mycobacteria. Culture results were not available in 3 cases. We propose ISH as a relatively simple and rapid method to differentiate mycobacteria on formalin-fixed, paraffin-embedded specimens (it is more specific than usual histologic stains) and as an alternative to polymerase chain reaction, allowing the morphologic evaluation of positive bacilli.
Zerbi
P
P
Pathology Unit, Institute of Biomedical Sciences, L. Sacco University of Milan, Italy.
Schønau
A
A
Bonetto
S
S
Gori
A
A
Costanzi
G
G
Duca
P
P
Vago
L
L
D001344:Autopsy; D001706:Biopsy; D005557:Formaldehyde; D017403:In Situ Hybridization / Q000379:methods*; D009164:Mycobacterium Infections / Q000175:diagnosis* / Q000382:microbiology; D009169:Mycobacterium tuberculosis / Q000145:classification / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification*; D015341:Nucleic Acid Probes / Q000235:genetics; D016612:Paraffin Embedding; D020135:Peptide Nucleic Acids; D012680:Sensitivity and Specificity; D016707:Tissue Fixation
D015341:Nucleic Acid Probes; D020135:Peptide Nucleic Acids; D005557:Formaldehyde