Usefulness of PCR and Antigen Latex Agglutination Test with Samples Obtained by Transthoracic Needle Aspiration for Diagnosis of Pneumococcal Pneumonia

Abstract

In a large number of cases, the etiology of community-acquired pneumonia (CAP) is not established. Some cases are probably caused byStreptococcus pneumoniae. Transthoracic needle aspiration (TNA) culture has a limited sensitivity which might be improved by antigen detection or gene amplification techniques. We evaluated the capacity of a PCR assay and a latex agglutination test to detectS. pneumoniae in samples obtained by TNA from 95 patients with moderate-to-severe CAP. Latex agglutination and PCR had sensitivities of 52.2 and 91.3%, specificities of 88.7 and 83.3%, positive predictive values of 62.3 and 65.6%, and negative predictive values of 83.3 and 96.5%, respectively, when culture techniques were used as the “gold standard.” When we considered expanded criteria for the diagnosis of pneumococcal pneumonia as a standard for our calculations, latex agglutination and PCR had sensitivities of 53.6 and 89.7%, specificities of 93.0 and 90.0%, positive predictive values of 78.9 and 81.3%, and negative predictive values of 80.3 and 94.7%, respectively. The additional diagnosis provided by the PCR assay compared to latex agglutination was 12.2% (95% confidence interval of the difference from 0.4 to 20.1%). PCR was more sensitive than TNA culture, particularly in patients who had received prior antibiotic therapy (83.3 versus 33.3%). Although PCR is a very sensitive and specific technique, it has not proved to be cost-effective in clinical practice. Conversely, latex agglutination is a fast and simple method whose results might have significant implications for initial antibiotic therapy.

PCR Improves Diagnostic Yield from Lung Aspiration in Malawian Children with Radiologically Confirmed Pneumonia

“…There are now over 35 reported studies of pneumonia in children where lung aspirate has been used [4], [5], [6], [10]. In the review of the published series up to 1999 the pneumothorax complication rate was 3.3%.…”

“…However, as is the case for blood culture, the yield from lung aspirate culture is likely to be affected by prior antibiotic usage, especially for the more fastidious organisms, such as Streptococcus pneumoniae. PCR of lung aspirate fluid increases the yield further [5], [6] especially in patients who have received antibiotics [7].…”

04 – Apport des explorations microbiologiques au diagnostic des infections des voies respiratoires basses

“…Diagnostic des PAC à pneumocoque par la PCR [150][151][152][153][154][155] Études Milieux de réalisation PCR Référence PCR+/référence+ PCR+/référence- [150] Liquide [160]. L'immunofluorescence est la technique de référence.…”

“…Dans le premier cas, les auteurs ont évalué la sensibilité à 78 % et la spécificité à 93 %. Dans le second cas, la sensibilité est de 91,3 % et la spécificité de 83,3 %.Dans le Tableau 24, sont rapportés quelques résultats d'études significatives[150][151][152][153][154][155]. Ces données montrent bien que même en se limitant aux PAC avec hémoculture(s) positive (s), la fréquence de positivité de la PCR réalisée sur le sérum varie considérablement d'une étude à l'autre.…”

Guidelines for the Diagnosis and Treatment of Community-Acquired Pneumonia. Spanish Society of Pulmonology and Thoracic Surgery (SEPAR)

“…Sensitivity improves significantly when the culture of these samples is complemented by antigen detection or gene amplification techniques (level II evidence). 74 Although polymerase chain reaction is a more sensitive technique than latex agglutination, the latter is more often used because it is more cost-effective, quicker, and simpler, and it provides useful information to support the decision concerning initial treatment (level II evidence). 74,75 Transthoracic fine needle aspiration may be considered in cases of abscessed CAP and in patients who do not respond treatment.…”