Journal List > Tuberc Respir Dis > v.64(3) > 1001203

Song, Myung, Choi, Jeon, Kang, Lee, Cho, Choi, Shin, Park, Choi, and Kim: Multiplex PCR of Endotracheal Aspirate for the Detection of Pathogens in Ventilator Associated Pneumonia

Abstract

Background

Early identification of pathogens can improve the prognosis of patients with ventilator associated pneumonia (VAP). In the present study, we evaluated the feasibility of performing multiplex PCR for endotracheal aspirates to detect three important pathogens (P. aeruginosa, K. pneumoniae and MRSA) in patients with VAP.

Methods

The endotracheal aspirates of 24 patients were collected within 24 hours of the diagnosis of VAP for performing multiplex PCR. Forward and reverse primers were designed to target the specific site of each pathogen (the oprL gene for P. aeruginosa, 16S rRNA for K. pneumoniae and the mec gene for MRSA). We analyzed the clinical data of the VAP patients, including the culture reports for the endotracheal aspirates.

Results

Twenty-four patients (M:F=18:6, mean age=70±11) with VAP were enrolled. Pathogens were isolated from 11 patients (P. aeruginosa in 2, K. pneumoniae in 1, MRSA in 2, other enteric Gram negative bacilli in 3, S. pneumoniae in 2 and mixed infection in 1). Multiplex PCR detected three cases of P.aeruginosa (2 cases coincided with the culture reports) and four cases of K. pneumoniae (1 matched with the culture report). PCR detected two MRSA cases, which did not coincide with the culture reports.

Conclusion

Multiplex PCR of the endotracheal aspirate showed some ability to detect Gram negative bacilli, although caution is required when interpreting the results.

Figures and Tables

Figure 1
Multiplex PCR for MRSA, P. aeruginosa and K. pneumoniae. Within 24 hours of the diagnosis of VAP, endotracheal aspirate was collected for multiplex PCR. Forward and reverse primers were designed to target the specific site of each pathogen (oprL gene for P. aeruginosa, 16S rRNA for K. pneumoniae and mec gene for MRSA). 504bp: Pseudomonas aeruginosa; 270bp: Staphylococcus aureus (MRSA); 117bp: K. Pneumoniae; M: 100bp marker; ?? negative control; +: positive control.
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Table 1
Demographic dataand comorbidities of patients with ventilator-associated pneumonia
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CNS: central nervous system; COPD: chronic obstructive pulmonary disease; DM: diabetes mellitus.

Table 2
Microbiologic data of endotracheal aspirate fluid
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Table 3
Culture vs multiplex PCR
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Table 4
Pathogens, initial antibiotics, adequacy of antibiotics and final outcome
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