Validation of pneumococcal iron acquisition (piaA) gene for accurate identification of Streptococcus pneumoniae
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Date
2018-12
Journal Title
Journal ISSN
Volume Title
Publisher
Indian Association of Medical Microbiologists
Abstract
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�.82) and specificity remained the same P < 0.001. The level of agreement between the PCR and lytA-sequencing was found to be moderate (? = 0.694; 95% CI = 0.432�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.
Description
Keywords
LytA gene, pneumococcal iron acquisition gene, polymerase chain reaction, Streptococcus pneumoniae
Citation
Peela SC, Sistla S, Tamilarasu K, Krishnamurthy S, Adhishivam B. Validation of pneumococcal iron acquisition (piaA) gene for accurate identification of Streptococcus pneumoniae. Indian Journal of Medical Microbiology. 2018 Dec; 36(4): 504-507