AVOIDING ARTIFACTS IN THE INFANT RAT MODEL FOR BACTERIAL-MENINGITIS -USE OF SANGUR TEST STRIPS FOR THE RAPID QUANTIFICATION OF BLOOD CONTAMINATION IN CEREBROSPINAL-FLUID

The infant rat model is widely used to study the pathogenesis of menin gitis caused by a variety of gram-positive and gram-negative bacteria. However, the interpretation of published results concerning meningiti s is difficult in many records because the fact that blood contaminati on of the cerebrospinal fluid (CSF) cannot be avoided during the traum atic puncture procedure has not been taken into consideration. Since b acterial invasion of the central nervous system develops following bac teremia in this model, blood contamination of the CSF leads to a falsi fication of the CSF bacterial counts. Here we present an evaluation of a rapid and quantitative test for CSF blood contamination using Sangu r test strips. The procedure requires minimal amounts of CSF and allow s direct calculation of the CSF bacterial load due to blood contaminat ion and, thus, provides refined criteria for the presence of bacterial meningitis in the infant rat model. It is superior to the detection o f erythrocytes using a hemocytometer since it is less time consuming. Furthermore, we demonstrate the value of this method for the experimen tal infection of rats with Neisseria meningitis.