Initial empiric therapy for CSF shunt infection should include broad coverage that includes gram-negative aerobic bacilli including pseudomonas and gram-positive organisms including Staph aureus and coagulase negative staphylococcus, such as a combination of ceftazidime and vancomycin. Some clinicians add either parenteral or intrathecal aminoglycosides to provide enhanced pseudomonas coverage, although the efficacy of this is not clear at this time. Meropenem and aztreonam are additional options that are effective against gram-negative bacterial infections.[18]