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Detection of Blastocystis in clinical stool specimens using three different methods and morphological examination in
Shashiraja Padukone1, Jharna Mandal1, Nonika Rajkumari1
1Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India.
Background:
Blastocystis was identified almost a century ago, yet its biology and pathogenicity status in humans is obscure. Studies on Blastocystis in India are scanty and are mostly microscopy based. This study compared three detection modalities to determine their efficiency in the identification of Blastocystis in human feces.
Materials And Methods:
A total of 279 stool samples were screened using microscopy, culture (Jones' medium), and polymerase chain reaction (PCR)-based methods. Among the three, PCR is considered the gold standard test for detection of Blastocystis, as it helps to authenticate the sensitivity, specificity, and kappa agreement obtained by the other two tests. The morphological features of Blastocystis were recorded at 24, 48, and 72 h. After positive morphological identification, ten samples were cultured on Löwenstein-Jensen (LJ) medium and Locke's egg slant medium.
Results:
The sensitivity and specificity determined on the basis of microscopy were 36.2% and 99.4%, respectively. On the other hand, Jones' medium showed 67.6% sensitivity and 100% specificity. Further, we documented various morphological and reproductive features of Blastocystis using various staining techniques on cultures positive in Jones' medium. In addition, we also found that LJ medium was not equally efficacious as Jones' medium in assisting the growth of Blastocystis.
Conclusions:
Although molecular diagnosis is a necessary tool for understanding the true epidemiology of Blastocystis, in laboratories devoid of molecular detection facilities, stool microscopy in conjunction with stool culture on Jones' medium could serve as the best alternative tool for the detection of Blastocystis.
Insights
Microscopy and Jones' medium culture are effective alternatives for detecting Blastocystis in resource-limited settings. These methods offer reliable identification when molecular diagnostics are unavailable for Blastocystis analysis.
Area of Science:
- Medical Parasitology
- Microbiology
- Molecular Diagnostics
Background:
- Blastocystis, identified a century ago, remains poorly understood regarding its human biology and pathogenicity.
- Studies on Blastocystis in India are limited and primarily rely on microscopy.
- This study aimed to evaluate detection methods for Blastocystis in human fecal samples.
Purpose of the Study:
- To compare the efficiency of microscopy, culture (Jones' medium), and polymerase chain reaction (PCR) for Blastocystis identification.
- To assess the sensitivity, specificity, and agreement of non-molecular methods against PCR as the gold standard.
- To document morphological and reproductive characteristics of Blastocystis.
Main Methods:
- Screening of 279 stool samples using microscopy, Jones' medium culture, and PCR.
- Morphological feature recording at 24, 48, and 72 hours.
- Culture of positive samples on Löwenstein-Jensen (LJ) and Locke's egg slant media.
Main Results:
- Microscopy sensitivity: 36.2%, specificity: 99.4%.
- Jones' medium culture sensitivity: 67.6%, specificity: 100%.
- LJ medium was less effective than Jones' medium for Blastocystis growth.
Conclusions:
- Molecular diagnosis is crucial for accurate Blastocystis epidemiology.
- Stool microscopy combined with Jones' medium culture is a viable alternative for Blastocystis detection in labs lacking molecular facilities.