Rapid Isolation and Identification of Pneumonia-Associated Pathogens from Sputum Samples Combining an Innovative Sample Preparation Strategy and Array-Based Detection

Isolation of pathogenic bacteria from sputum samples using a 3D-printed cartridge system

Within this contribution we introduce a 3D-printed cartridge system enabling the convenient and cost-efficient sample preparation from sputum for subsequent PCR based detection schemes. The developed fluidic system operates on pneumatic actuations. The closed system ensures a very low probability for contamination during sample processing, which is crucial when using a highly sensitive detection method such as PCR. The enrichment of the bacterial cells is achieved using different types of amine-functionalized particles. Our particle-based sample preparation approach yields intact and viable bacterial cells. Accordingly, not only PCR-based detection schemes can be employed, but also spectroscopic methods and biochemical tests, which require cultivation steps, are possible. The cartridge design in principle is compatible with magnetic and non-magnetic particle types. We investigated both variants and found that the performance of expanded glass beads is superior over the magnetic particles within the cartridge. Owing to the rather large size of the expanded glass beads, the dimensions of the channels can be enlarged, leading to lower hydrodynamic resistances, which is beneficial when processing viscous samples such as sputum. We verified the performance of our system using both artificial and real sputum samples containing Escherichia coli and Moraxella catarrhalis.

Advances in molecular diagnostic tests for pneumonia

PURPOSE OF REVIEW

Pneumonia is the main global cause of sepsis, and has been associated with high morbidity and high short and long-term mortality rates. As it may be caused by a wide spectrum of microorganisms, microbial diagnosis is challenging and the choice of adequate therapy remains an important problem. This review focuses on recently published studies of microbiological diagnostic tests and clinical assessments for pneumonia, including community-acquired pneumonia, hospital-acquired pneumonia, and ventilator-associated pneumonia.

RECENT FINDINGS

Over the past decade, the microbiological diagnosis of pneumonia has improved significantly - thanks to the development and implementation of molecular diagnostic tests for identifying the most frequent pathogens causing pneumonia and for determining their patterns of resistance. Molecular methods for the diagnosis of pneumonia focus on multiple target detection systems and pathogen detection arrays, and, more recently, have been used in combination with mass spectrometry.

SUMMARY

The implementation of rapid diagnostic techniques in routine clinical practice able to identify and determine the resistance patterns of the causative microbes may transform the management of pneumonia, improving the selection and administration of antimicrobial therapies especially in critically ill patients. The validation of new diagnostic technology platforms is crucial in order to assess their usefulness and to guide antimicrobial treatment in this population.