New Perspectives for Prosthetic Valve Endocarditis: Impact of Molecular Imaging by FISHseq Diagnostics.

BACKGROUND: The microbial etiology of prosthetic valve infective endocarditis (PVE) can be difficult to identify. Our aim was to investigate the benefit of molecular imaging technique fluorescence in situ hybridization (FISH) combined with 16S rRNA-gene polymerase chain reaction (PCR) and sequencing (FISHseq) for the analysis of infected prosthetic heart valves. METHODS: We retrospectively evaluated the diagnostic outcome of 113 prosthetic valves from 105 patients with suspected PVE, treated in 2003-2013 in the Department of Cardiac Surgery, Charité University Medicine Berlin. Each prosthetic valve underwent cultural diagnostics and was routinely examined by FISH combined with 16S rRNA gene PCR and sequencing. We compared classical microbiological culture outcomes (blood and valve cultures) with FISHseq results and evaluated the diagnostic impact of the molecular imaging technique. RESULTS: Conventional microbiological diagnostic alone turned out to be insufficient, as 67% of preoperative blood cultures were noninformative (negative, inconclusive, or not obtained) and 67% of valve cultures remained negative. FISHseq improved the conventional cultural diagnostic methods in PVE in 30% of the cases and increased diagnostic accuracy. Of the valve culture-negative PVE cases, FISHseq succeeded in identifying the causative pathogen in 35%. CONCLUSIONS: FISHseq improves PVE diagnostics, complementing conventional cultural methods. In addition to species identification, FISH provides information about the severity of PVE and state of the pathogens (eg, stage of biofilm formation, activity, and localization on and within the prosthetic material). As a molecular imaging technique, FISHseq enables the unambiguous discrimination of skin flora as contaminant or infectious agent.

[The impact of premature rupture of membranes (PROM) on neonatal outcome]. / Wplyw przedwczesnego pekniecia blon plodowych (PROM) na stan noworodka.

OBJECTIVE: The aim of the following study was to evaluate the impact of premature rupture of membranes (PROM) on neonatal outcome, particularly on the incidence of intrauterine infections (IUI). MATERIAL AND METHODS: The study included 428 newborns, born after PROM and hospitalized in the Department of Neonatology at Poznan University of Medical Sciences in 2006. The influence of selected variables on the development of IUI and other complications was analyzed. RESULTS: IUI occurred in 124 newborns (29%). The odds ratio (OR) of IUI incidence increased with decreasing gestational age, birth weight and Apgar score, as well as with increasing duration of the time between PROM and birth, called the latency period. Logistic regression showed that IUI was significantly influenced by the latency period (OR=1.37; 95% CI: 1.10-1.71; p<0.01), gestational age (OR=2.29; 95% CI: 1.59-3.30; p<0.0001) and 5-minute Apgar score (OR=2.50; 95% CI: 1.57-3,98; p<0.001). The incidence of other complications such as prematurity respiratory distress syndrome, respiratory failure, intraventricular hemorrhage, and anemia increased with the duration of the latency period. Compared to uninfected infants, the infected ones were characterized by lower birth weight, lower gestational age, lower Apgar score and poorer laboratory results. CONCLUSIONS: Among neonates born from pregnancies complicated with PROM, the incidence of IUI is significantly influenced by the latency period, gestational age and 5-minute Apgar score. The incidence of other complications increases with the duration of the latency period. Prematurity is an important contributor to morbidity in this group of neonates.

Aerococcus urinae - A potent biofilm builder in endocarditis.

The diagnosis of infective endocarditis (IE) remains a challenge. One of the rare bacterial species recently associated with biofilms and negative cultures in infective endocarditis is Aerococcus urinae. Whether the low number of reported cases might be due to lack of awareness and misidentification, mainly as streptococci, is currently being discussed. To verify the relevance and biofilm potential of Aerococcus in endocarditis, we used fluorescence in situ hybridization to visualize the microorganisms within the heart valve tissue. We designed and optimized a specific FISH probe (AURI) for in situ visualization and identification of A. urinae in sections of heart valves from two IE patients whose 16S rRNA gene sequencing had deteced A. urinae. Both patients had a history of urinary tract infections. FISH visualized impressive in vivo grown biofilms in IE, thus confirming the potential of A. urinae as a biofilm pathogen. In both cases, FISH/PCR was the only method to unequivocally identify A. urinae as the only causative pathogen for IE. The specific FISH assay for A. urinae is now available for further application in research and diagnostics. A. urinae should be considered in endocarditis patients with a history of urinary tract infections. These findings support the biofilm potential of A. urinae as a virulence factor and are meant to raise the awareness of this pathogen.