Improving the diagnostic tools for spontaneous bacterial peritonitis

Ascites is in patients with cirrhosis of the liver the most common
complication. The occurrence of an infection of ascitic fluid, spontaneous
bacterial peritonitis (SBP), is associated with high morbidity and mortality.
Early and adequate recognition of the infection makes it possible to start
antibiotic treatment at an early stage, thereby preventing associated
complications.
The current diagnostic tools have 2 downsides. First, the current standard for
determining infection in ascitic fluid is the polymorphonuclear leukocyte
count. This is determined in the laboratory and often takes a long time before
results become available, especially during after-office hours, causing a delay
in treatment. The use of dipstick-tests as bedside diagnostics of SBP can be a
good alternative for the rapid detection of infection.
The second shortcoming of the current diagnostics for SBP concerns the culture
method. Samples of all diagnostic and therapeutic paracenteses performed are
inoculated in blood culture bottles to detect the (possible) presence of a
causative micro-organism. In 60% of all ascitic fluid cultures in which an
infection is present, no micro-organism is currently identified. This makes it
impossible to adjust the antibiotic treatment for the causative micro-organism.

The aim of the study is to improve the diagnostic tools of spontaneous
bacterial peritonitis.
The primary aim is to evaluate the use of dipsticks as bedside diagnostics
compared to the current standard polymorphonuclear leukocyte count in
identifying an infection in ascitic fluid.
The secondary aim is to compare the current standard of ascitic fluid culture,
i.e. blood culture bottles, to other different microbiological methods in the
detection of micro-organism(s) present.

single-center prospective study

All patients with cirrhosis of the liver and ascites admitted to the ward of
gastroenterology and hepatology of the Erasmus Medical Center and who require
either a diagnostic or therapeutic paracentesis are asked to participate in the
study.
Ascites of patients who are included in the study will be screened for
infection by use of a dipstick test next to the standard polymorphonuclear
leukocyte count.
Next to the standard ascitic fluid culture, ascites will undergo different
microbiological methods, i.e inoculation of larger volume of ascites, special
culture for fungi, for the detection of micro-organisms. In those cases where
no micro-organism is identified, a PCR is used to detect bacterial DNA.

No extra burden or risk for the patient is associated with this study since
samples are obtained during standard treatment procedures. Ascitic fluid is
obtained from a paracentesis performed for general treatment. Blood sample is
obtained when blood is drawn for general laboratory diagnostics. No extra vena
punction is necessary.