부산대학교 도서관

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 piaAgene as a genetic marker for the identification of pneumococci. Methods:Twenty isolates were initially sequenced for lytAgene using published primers. PiaA-PCR (piaApolymerase 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, piaAPCR 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.