Parasitology Research

, Volume 117, Issue 8, pp 2585–2590 | Cite as

Exacerbated symptoms in Blastocystis sp.-infected patients treated with metronidazole: two case studies

  • Arutchelvan Rajamanikam
  • Suresh KumarEmail author
  • Chandramathi Samudi
  • Madhav Kudva
Original Paper


Blastocystis sp. is a gastrointestinal (GI) protozoan parasite reported to cause non-specific GI symptoms including diarrhea, flatulence, abdominal pain, and nausea. Complete eradication of Blastocystis sp. is rather challenging even with the drug of choice, i.e., metronidazole. Here, we report on two Blastocystis sp.-infected individuals, who presented increased parasite load and exacerbated symptoms upon treatment with the usual recommended dosage and regime of metronidazole. The two studies uniquely demonstrate for the first time a cyst count as high as fivefold more than the original cyst count before treatment and show an exacerbation of GI symptoms despite treatment. The study provides additional support in recognizing metronidazole resistance in Blastocystis sp. and its consequences towards the pathogenicity of the parasite.


Blastocystis sp. Metronidazole Cysts Exacerbation of symptoms Subtypes 



The authors would like to thank the staffs of Dr. Madhav Kudva’s Clinic, Pantai Medical Centre, and the staffs from Department of Parasitology, Faculty of Medicine, University Malaya.

Funding information

This work was entirely supported by Fundamental Research Grant Scheme (FRGS), FP015-2017A, and Postgraduate Research Grant (PPP), PG140-2016A.

Compliance with ethical standards

This study was approved by the Medical Ethics Committee, University Malaya Medical Centre.

Competing interests

The authors declare that they have no conflict of interest.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  • Arutchelvan Rajamanikam
    • 1
  • Suresh Kumar
    • 1
    Email author
  • Chandramathi Samudi
    • 2
  • Madhav Kudva
    • 3
  1. 1.Department of Parasitology, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
  2. 2.Department of Medical Microbiology, Faculty of MedicineUniversity of MalayaKuala LumpurMalaysia
  3. 3.Gastroenterology and Hepatology Specialist ClinicPantai HospitalKuala LumpurMalaysia

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