Introduction: Less invasive technique such as quantitative culture of Endotracheal Aspirate (ETA) with a threshold of 10⁵ to 10⁶ CFU/ml of exudates is considered as optimal for microbiological confirmation of Ventilator Associated Pneumonia (VAP). Therefore, the present study was conducted to compare quantitative culture of ET aspirates with qualitative culture in clinically suspected cases of VAP.

Methods: Endotracheal aspirate (ETA) was collected under aseptic precautions. Qualitative as well as quantitative cultures of the endotracheal aspirate were performed as per standard methods. Even a single colony in plate of 10^-5 dilution was considered as infection.

Results: Out of 130 ETA, 40.77% were VAP and 59.23% were non-VAP cases, according to clinical criteria. Though sensitivity of qualitative culture was 100% but specificity was only 22%. Sensitivity of quantitative culture was 94.34% and specificity was 88.31%. All VAP cases showed growth in qualitative culture (100%). Qualitative culture in the Non-VAP group showed growth in 77.92% cases, which significantly reduced to 11.69% in quantitative culture. All VAP cases showed growth in qualitative culture (100%).

Conclusion: To potentially improve the specificity of the diagnosis of VAP, quantitative cultures of respiratory secretions should be done. Of the quantitative techniques, quantitative endotracheal aspirate culture is least invasive, most readily available, least expensive, requires least experience and is easily repeatable. 

Keywords: Ventilator-associated pneumonia, Endotracheal aspirate,  Quantitative culture.

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Dr Anuradha De

Professor, Department of Microbiology, Topiwala National Medical College & B. Y. L. Nair Ch. Hospital

A. L. Nair Road, Mumbai Central, Mumbai- 400008, Maharashtra, India

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