Evaluation of formalin-ether sedimentation and trichrome staining techniques

Its effectiveness in detecting Entamoeba histolytica/dispar/moshkovskii in stool samples

Tengku Shahrul Anuar, Hesham M. Al-Mekhlafi, Mohamed Kamel Abdul Ghani, Edariah Abu Bakar, Siti Nor Azreen, Fatmah Md Salleh, Norhayati Moktar

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

This study was conducted to evaluate two routinely microscopic diagnostic methods in comparison with single-round PCR assay as the reference technique to detect Entamoeba histolytica/dispar/moshkovskii. Examination was performed on 500 stool samples obtained from Orang Asli communities in different states of Malaysia using formalin-ether sedimentation, trichrome staining and single-round PCR techniques. Ninety-three stool samples were detected E. histolytica/dispar/moshkovskii positive by routine microscopy, while single-round PCR detected 106 positive samples. Additional positives detected by PCR assay were eventually confirmed to be negative by both microscopic techniques. Detection rate of E. histolytica/dispar/moshkovskii was highest in combination techniques (18.6%), followed by trichrome staining (13.4%) and formalin-ether sedimentation (11.2%) techniques. Single-round PCR detected 21.2% of the stool samples. The sensitivity and specificity of formalin-ether sedimentation and trichrome staining techniques compared to the reference technique were 31.1% (95% CI: 29.0-36.0) and 94.2% (95% CI: 89.8-98.9), and 53.8% (95% CI: 46.0-76.2) and 97.5% (95% CI: 92.8-99.1), respectively. However, the sensitivity [59.4% (95% CI: 48.9-78.5)] of the method increased when both techniques were performed together, but the specificity decreased to 92.4% (95% CI: 81.0-98.0). The agreement between the reference technique, trichrome staining and combination techniques were statistically significant by Kappa statistics (trichrome staining: K=0.592, p<0.05; combination techniques: K=0.543, p<0.05). Hence, the combination technique is recommended to be used as a screening method in the diagnosis of E. histolytica/dispar/moshkovskii infections either for clinical or epidemiological study.

Original languageEnglish
Pages (from-to)344-348
Number of pages5
JournalJournal of Microbiological Methods
Volume92
Issue number3
DOIs
Publication statusPublished - Mar 2013

Fingerprint

Entamoeba histolytica
Ether
Formaldehyde
Staining and Labeling
Polymerase Chain Reaction
Malaysia
Epidemiologic Studies
Microscopy
Sensitivity and Specificity
Infection

Keywords

  • Entamoeba histolytica/dispar/moshkovskii
  • Formalin-ether sedimentation
  • Single-round PCR
  • Trichrome staining

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Microbiology (medical)

Cite this

Evaluation of formalin-ether sedimentation and trichrome staining techniques : Its effectiveness in detecting Entamoeba histolytica/dispar/moshkovskii in stool samples. / Anuar, Tengku Shahrul; Al-Mekhlafi, Hesham M.; Abdul Ghani, Mohamed Kamel; Abu Bakar, Edariah; Azreen, Siti Nor; Salleh, Fatmah Md; Moktar, Norhayati.

In: Journal of Microbiological Methods, Vol. 92, No. 3, 03.2013, p. 344-348.

Research output: Contribution to journalArticle

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abstract = "This study was conducted to evaluate two routinely microscopic diagnostic methods in comparison with single-round PCR assay as the reference technique to detect Entamoeba histolytica/dispar/moshkovskii. Examination was performed on 500 stool samples obtained from Orang Asli communities in different states of Malaysia using formalin-ether sedimentation, trichrome staining and single-round PCR techniques. Ninety-three stool samples were detected E. histolytica/dispar/moshkovskii positive by routine microscopy, while single-round PCR detected 106 positive samples. Additional positives detected by PCR assay were eventually confirmed to be negative by both microscopic techniques. Detection rate of E. histolytica/dispar/moshkovskii was highest in combination techniques (18.6{\%}), followed by trichrome staining (13.4{\%}) and formalin-ether sedimentation (11.2{\%}) techniques. Single-round PCR detected 21.2{\%} of the stool samples. The sensitivity and specificity of formalin-ether sedimentation and trichrome staining techniques compared to the reference technique were 31.1{\%} (95{\%} CI: 29.0-36.0) and 94.2{\%} (95{\%} CI: 89.8-98.9), and 53.8{\%} (95{\%} CI: 46.0-76.2) and 97.5{\%} (95{\%} CI: 92.8-99.1), respectively. However, the sensitivity [59.4{\%} (95{\%} CI: 48.9-78.5)] of the method increased when both techniques were performed together, but the specificity decreased to 92.4{\%} (95{\%} CI: 81.0-98.0). The agreement between the reference technique, trichrome staining and combination techniques were statistically significant by Kappa statistics (trichrome staining: K=0.592, p<0.05; combination techniques: K=0.543, p<0.05). Hence, the combination technique is recommended to be used as a screening method in the diagnosis of E. histolytica/dispar/moshkovskii infections either for clinical or epidemiological study.",
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