Closing the Brief Case: Neonatal Meningitis Caused by Listeria monocytogenes Diagnosed by Multiplex Molecular Panel

Abstract

Answer: c. Listeria species are intrinsically resistant to several classes of antibiotics, including broad-spectrum cephalosporins, first-generation quinolones, fosfomycin, and monobactams. Recognizing the intrinsic resistance to broad-spectrum cephalosporins is clinically important, as they are commonly employed to empirically treat sepsis and meningitis of unknown etiology. The mechanism associated with cephalosporin resistance in Listeria spp. is complex and is thought to be secondary to unique penicillin binding protein 3 in the cytoplasmic membrane, which is the primary target for other beta-lactams but does not bind well to cephalosporins. TAKE-HOME POINTS• The constellation of low glucose in the CSF, high protein, and pleocytosis is highly suggestive of bacterial meningitis, even in the absence of a positive culture, and warrants empirical treatment.• L. monocytogenes is a Gram-positive, rod-shaped bacterium that is a rare but recognized cause of bacterial meningitis, particularly in neonates and the immunocompromised. It can be particularly challenging to isolate by culture.• New molecular technologies are available that can rapidly and accurately detect a broad spectrum of pathogens directly in CSF specimens and can be particularly useful in providing definitive etiology when organisms are uncultivable because of a fastidious nature or exposure to antimicrobials prior to lumbar puncture. These novel technologies can be used to augment traditional culture and other techniques for the diagnosis of infections of the central nervous system.

Implementation of the FilmArray ME panel in laboratory routine using a simple sample selection strategy for diagnosis of meningitis and encephalitis

“…Conventional assays confirmed presence of VZV and H. influenzae, whereas HHV-6 was not found by specific PCR Using this selection criteria we selected 171/4623 CSF specimens for additional syndromic molecular testing. Overall we observed positive results in 56/171 (32%), which is higher than in other published studies [6,7,[9][10][11][12][34][35][36][37][38] and substantially higher compared to the multicenter evaluation study [6] and three other studies [7,32,33], that reported positivity rates of under 15% (p < 0.0001). In addition, we could increase the amount of bacterial pathogens to 53% of the specimens, again this is more than in other published studies that observed positive ranges for bacterial pathogens between 15 and 37% [6,7,32,33].…”

Implementation of the FilmArray ME panel in laboratory routine using a simple sample selection strategy for diagnosis of meningitis and encephalitis

“…In addition, we could increase the amount of bacterial pathogens to 53% of the specimens, again this is more than in other published studies that observed positive ranges for bacterial pathogens between 15-37% [6,7,32,33]. Indeed, bacteria were the most abundant In concordance with other studies [6,7,[9][10][11][12][34][35][36][37][38], S. pneumoniae (17/30) In four samples, potentially false positive results of FilmArray ME panel occurred, including three samples tested positive for bacterial pathogens by multiplex PCR that remained culture negative.…”

“…Using this selection criteria we selected 171/4623 CSF specimens for additional syndromic molecular testing. Overall we observed positive results in 56/171 (32%), which is higher than in other published studies [6,7,[9][10][11][12][34][35][36][37][38] and substantially higher compared to the multicenter evaluation study [6] and three other studies [7,32,33], that reported positivity rates of under 15% (p<0.0001). In addition, we could increase the amount of bacterial pathogens to 53% of the specimens, again this is more than in other published studies that observed positive ranges for bacterial pathogens between 15-37% [6,7,32,33].…”

Impact of a Rapid Herpes Simplex Virus PCR Assay on Duration of Acyclovir Therapy

“…Patients who were positive for respiratory viruses were also less likely to be discharged with oral antimicrobial therapy (26). We previously described two cases in which rapid diagnosis of bacterial meningitis, attributable to Listeria monocytogenes and Haemophilus influenzae, with a molecular panel assay allowed definitive diagnosis and optimization of antimicrobial therapy (27)(28)(29). In this study, the availability of the HSV PCR results on a 24-h/7-day basis resulted in a significant reduction in the duration of acyclovir treatment in the postimplementation arm.…”