A 3 week old child presented to the pediatrician with meningitis. A presumptive diagnosis of late onset of a perinatal infection was made. The CSF culture was positive for gram positive bacilli. Which of the following characteristic of this bacteria would be helpful in differentiating it from other bacteria agents?

(D) Motility at 25degC # Common causes of Meningits according to age are;> First 2 months of life: Group B and D streptococci (Streptococcus agalactiae) Gram negative enteric bacilli (Escherichia coli) Listeria monocytogenes H. influenzae (type b & non-encapsulated strain) - Rare> 2 months to 12 years of age: S. pneumoniae N. meningitidis H. influenzae type b> Subsequent to the implementation of universal immunization against the H. influenzae (beginning at 2 months of age), the incidence of H. influenzae dropped precipitously.> Meningitis (2 months -12 years) now is most commonly caused by S. pneumoniae & N. meningitidis.> T-lymphocyte defect (congenital or acquired by chemotherapy, AIDS or malignancy): t risk of L. monocytogenes infection.> Peak incidence of H. influenzae type B: 6-9 months of age.> Possible diagnosis in this 3 week old child.> Streptococci (Ruled out cause CSF shows gram positive bacilli).> E. coli - (Ruled out gram Negative)