title: Comparative evaluation of staining techniques and polymerase chain reaction for diagnosis of intestinal microsporidiosis in immunocompromised patients.
abstract: BACKGROUND
  Microsporidia, which causes chronic diarrhoea in immunocompromised hosts, are often missed. The commonest diagnostic techniques include modified trichrome (MT) stain; however, it requires expertise and does not identify the species, which is important therapeutically. Other diagnostic techniques include Calcoflour white staining and polymerase chain reaction (PCR). Data on comparative utility of different diagnostic techniques are scanty.
  
  
  OBJECTIVE
  Comparison of Calcoflour white, MT staining and PCR for the diagnosis of intestinal microsporidiosis.
  
  
  METHODS
  Fecal samples of consecutive immunocompromised patients were evaluated for Microsporidia using Calcoflour white, MT stain and PCR. Species were identified by restriction fragment length polymorphism using HindIII and HinfI. Presence of Microsporidia by two or more techniques was considered true positive. Absence of Microsporidia by all three techniques was taken as true negative.
  
  
  RESULTS
  Of 730 patients, Microsporidia was detected in 28 (3.8%), 250 (34.2%) and 30 (4.1%) patients by MT, Calcoflour white stains and PCR, respectively. Enterocytozoon bieneusi was identified in all 30 (4.1%) patients. 30 (4.1%) and 479 (65.6%) patients were true positive and true negative, respectively. Sensitivity and specificity of Calcoflour white, MT stains and PCR were 100%, 93.8%, 96.8% and 68.5%, 100% and 99.8%, respectively. Diagnostic accuracy of MT stain and PCR was superior to Calcoflour white (99.6% vs. 69.8%; P < 0.05).
  
  
  CONCLUSIONS
  Though Calcoflour white stain is a highly sensitive, but it is nonspecific technique. MT stain and PCR with high sensitivity, specificity and diagnostic accuracy are useful diagnostic techniques. Furthermore, PCR is useful for species identification, which has therapeutic implications.
authors.affiliation: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Ujjala
authors.initials: U
authors.lastname: Ghoshal
authors.affiliation: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Sonali
authors.initials: S
authors.lastname: Khanduja
authors.affiliation: Department of Clinical Immunology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Agarwal
authors.affiliation: Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Tapan N
authors.initials: TN
authors.lastname: Dhole
authors.affiliation: Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India.
authors.forename: Uday C
authors.initials: UC
authors.lastname: Ghoshal
keywords: Comparative evaluation; diagnostic techniques; intestinal microsporidiosis