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Year : 2018  |  Volume : 36  |  Issue : 4  |  Page : 504--507

Validation of pneumococcal iron acquisition (piaA) gene for accurate identification of Streptococcus pneumoniae

Sreeram Chandra Murthy Peela1, Sujatha Sistla1, Kadhiravan Tamilarasu2, Sriram Krishnamurthy3, B Adhishivam4 
1 Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
2 Department of Medicine, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
3 Department of Pediatrics, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
4 Department of Neonatology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India

Correspondence Address:
Dr. Sujatha Sistla
Department of Microbiology, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry - 605 006
India

Purpose: The pneumococcal iron acquisition (piaA) gene is found to be highly specific and hence proposed as a diagnostic marker for identification of pneumococci. The objective of the present study was to evaluate the piaA gene as a genetic marker for the identification of pneumococci. Methods: Twenty isolates were initially sequenced for lytA gene using published primers. PiaA-PCR (piaA polymerase chain reaction) was performed using in-house primers and protocol. Based on the sensitivity and specificity results, a final sample of 30 pneumococcal isolates and 11 non-pneumococcal isolates confirmed with lytA- sequencing were selected. Statistical analyses were performed using OpenEpi v3.01 and GraphPad Quickcalc at P < 0.05 as the level of statistical significance. Results: Of the initial 20 samples tested, piaA PCR was positive in only 71.43% (10/14) of the pneumococcal isolates but was 100% specific (0/6 non-pneumococcal isolates) P = 0.011. When the PCR was performed on 41 samples, the sensitivity increased to 73.33% (95% of confidence interval [CI] = 55.55–85.82) and specificity remained the same P < 0.001. The level of agreement between the PCR and lytA-sequencing was found to be moderate (κ = 0.694; 95% CI = 0.432–0.955). Conclusions: PiaA-PCR can be used as a specific marker for the identification of pneumococcus, though it is less sensitive. As the level of agreement was moderate, further analyses on a large number of samples can give conclusive evidence for its use as a diagnostic marker for pneumococcus.

How to cite this article:
Peela SC, Sistla S, Tamilarasu K, Krishnamurthy S, Adhishivam B. Validation of pneumococcal iron acquisition (piaA) gene for accurate identification of Streptococcus pneumoniae.Indian J Med Microbiol 2018;36:504-507

How to cite this URL:
Peela SC, Sistla S, Tamilarasu K, Krishnamurthy S, Adhishivam B. Validation of pneumococcal iron acquisition (piaA) gene for accurate identification of Streptococcus pneumoniae. Indian J Med Microbiol [serial online] 2018 [cited 2020 Oct 28 ];36:504-507
Available from: https://www.ijmm.org/article.asp?issn=0255-0857;year=2018;volume=36;issue=4;spage=504;epage=507;aulast=Peela;type=0