Background and Aim:
Negative blood cultures are of considerable concern in the management of infective endocarditis (IE) and therapy. The purpose of this study was to support the conventional routinary diagnosis based on culture-dependent methods (blood and cardiac valve culture methods) with the introduction of a device able to destroy microbial biofilms in order to improve diagnosis, therapeutic approach and patient outcome.
One year and half prospective study of 40 patients (24 men, 16 women, mean age 66 years) underwent cardiac valve surgery. Samples were processed directly in the operating room using 0.1% dithiothreitol solution (MicroDTTect – 4i for infection, Monza - Italy). A comparison with sonication, traditional culture method and serological investigation were performed.
The use of MicroDTTect was successful in 5 out of 40 cases of IE. The detection of a the causative bacteria was possible as follow reported: methicillin-resistant S. aureus (2 cases), S. viridans, E. faecalis and P. mirabilis and S. aureus. Rickettsia conhori was serologically identified in one case only.
MicroDTTect allowed the growth of biofilm producing bacteria as the true causative agents responsible for IE, thus facilitating appropriate antibiotic treatment. This study was developed in an effort to reduce the number of cases of IE with no causative agent, by implementing in routine the use of a completely closed system for detecting biofilm-related bacteria, thus reducing the risk of environmental contamination. Microbiological staff worked directly in the operating room to prepare samples and quickly have antibiogram.