Peptide nucleic acid fluorescence in situ hybridization for identification of Listeria genus, Listeria monocytogenes and Listeria ivanovii.
A fluorescent in situ hybridization (FISH) method in conjunction with fluorescin-labeled peptide nucleic acid (PNA) probes (PNA-FISH) for detection of Listeria species was developed. In silico analysis showed that three PNA probes Lis-16S-1, Lm-16S-2 and Liv-16S-5 were suitable for specific identification of Listeria genus, Listeria monocytogenes and Listeria ivanovii, respectively. These probes were experimentally verified by their reactivity against 19 strains of six Listeria species (excluding newly described species Listeria marthii and Listeria rocourtiae) and eight other bacterial species. The PNA-FISH method was optimized as 30 min of hybridization with 0.2% Triton X-100 in the solution and used to identify 85 Listeria strains from individual putative Listeria colonies on PALCAM agar plates streaked from selectively enriched cultures of 780 food or food-related samples. Of the 85 Listeria strains, thirty-seven were identified as L. monocytogenes with the probe Lm-16S-2 and two as L. ivanovii with the probe Liv-16S-5 which was in agreement with the results obtained by the API LISTERIA method. Thus, the PNA-FISH protocol has the potential for identification of pathogenic Listeria spp. from food or food-related samples.
Food Safety Key Laboratory of Zhejiang Province, Zhejiang Entry-Exit Inspection and Quarantine Bureau, Hangzhou 310012, People's Republic of China.
Xiaofeng
X
Zhang
Shan
S
Wu
Ke
K
Li
Jiangbing
J
Shuai
Qiang
Q
Dong
Weihuan
W
Fang
D005506:Food Contamination; D005516:Food Microbiology; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008087:Listeria / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D008089:Listeria monocytogenes / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D009693:Nucleic Acid Hybridization; D015341:Nucleic Acid Probes; D017830:Octoxynol; D020135:Peptide Nucleic Acids
D015341:Nucleic Acid Probes; D020135:Peptide Nucleic Acids; D017830:Octoxynol