Bacterial infections are a major cause of hospitalization, with 5-10% of hospitalizations resulting in nosocomial infection in Europe and North America and more than 40% in South America, Sub‑Saharan Africa and Asia. Five out of six bacteria that most commonly cause nosocomial infection, are Gram-negative bacteria. They are responsible for 10-47% hospital-acquired pneumonia, 45–70% of ventilator-associated pneumonia, 20–30% of catheter-related bloodstream infections, and commonly cause other intensive care unit complication.

Bacterial cultures and other standard microbiological techniques, have been predominantly used for detection and identification of bacteria. However, cultivation and phenotypic tests take days and delay introduction of infection control measures. Additionally, as the conventional methods are unable to identify the causative agent quickly enough, infection is consequently often treated empirically with broad-spectrum antibiotics. This can lead to the emergence of antimicrobial resistance. Accurate diagnosis, rapid tracing of outbreak source, as well as robust approaches for assessing key epidemiological indicators, such as disease prevalence and incidence, and monitoring of drug resistance, is thus crucial. The needs for traceability and standardisation of nucleic acid measurements, together with the need for metrological support of measurements, including those for antimicrobial resistance have already been recognised on different levels, from research to state, and the importance of the metrological aspects have been emphasised in international projects (e.g. INFECT-MET, AntiMicroResist, SEPTIMET).

To enable reliable implementation of new technologies, they should be assessed in terms of accuracy and sensitivity. At the moment, higher order methods and reference materials that would provide reference for such assessments are lacking. The main objective of the proposed research is to develop and evaluate higher order methods for accurate measurement of Gram-negative bacteria causing nosocomial respiratory infection, and their susceptibility/resistance to antibiotics, and value assignment of calibrators or reference materials in order to establish a reference measurement system to support faster molecular diagnostics in the presented field.

The specific objectives of this research project are:

• to define the core measurement requirements for accurate and reproducible measurement associated with management of nosocomial respiratory tract infection with Gram–negative bacteria, including any potential antimicrobial resistance,
• to develop quantitative, validated and highly accurate measurement methodologies for the measurement,
• to develop methodologies for accurately assessing the performance of commercially available diagnostic assays and novel emerging approaches.

 

The proposed research will bring fuller understanding of the need for the metrological support in clinical setting and contribute to the prevention of unnecessary use of antibiotics in patients with illnesses, such as acute respiratory tract infections. The principle of development of reference methods and materials as well as principles of evaluation of emerging approaches will be transferable to other clinically relevant organisms.