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Volume 44, Number 2, April 2011

Polymerase chain reaction assay for the detection of Acinetobacter baumannii in endotracheal aspirates from patients in the intensive care unit


Mei-Chun Chiang, Shu-Chen Kuo, Yu-Chih Chen, Yi-Tzu Lee, Te-Li Chen, Chang-Phone Fung


Received: October 1, 2009    Revised: February 10, 2010    Accepted: April 16, 2010   

 

Corresponding author:

Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, No. 201, Section 2,
Shih-Pai Road, Taipei 11217, Taiwan.
E-mail address: tlchen@vghtpe.gov.tw (T.-L. Chen)



 

Background and purpose: 

We aim to evaluate the efficacy of polymerase chain reaction (PCR) to detect Acinetobacter baumannii in endotracheal aspirates



 

Methods:

Endotracheal aspirates and clinical data were collected from patients who were admitted to the intensive care unit of Taipei Veterans General Hospital between April 1 and August 31 in 2006. Bacterial isolates from endotracheal aspirate cultures were phenotypically identified as Acinetobacter calcoaceticus–A baumannii complex using the API ID 32GN system. The presence of A baumannii in the aspirate was also directly detected by multiplex PCR.



 

Results:

Ten of the 114 endotracheal aspirate cultures were positive for A calcoaceticus–A baumannii complex, and only nine of the isolates were confirmed as A baumannii by the multiplex PCR. Direct PCR detection showed that 40 (35.1%) of the endotracheal aspirates were positive for A baumannii. Using positive culture of A baumannii as the gold standard, the sensitivity of direct PCR detection was 100% (6 of 6), the specificity was 70.4% (38 of 54), the positive predictive value was 27.3% (6 of 22), and the negative predictive value (NPV) was 100% (38 of 38) among patients with A baumannii pneumonia. Among patients with A baumannii colonization, the sensitivity of direct PCR detection was 100% (3 of 3), the specificity was 70.6% (36 of 51), the positive predictive value was 16.7% (3 of 18), and the NPV was 100% (36 of 36).



 

Conclusion:

Direct PCR detection of A baumannii in endotracheal aspirates has a high sensitivity and NPV as compared with culture-based methods. Further studies are needed to determine the clinical applicability of this rapid detection test.

 



 

Key words:

Acinetobacter baumannii, Detection, Diagnosis, Polymerase chain reaction (PCR)