Background/Purpose: Infections are an important cause of morbidity and mortality in systemic lupus erythematosus (SLE) patients. These patients are more prone to develop infections, both because of intrinsic immune system abnormalities associated with the disease and immunosuppressive therapy. Listeria monocytogenes is a foodborne pathogen that may cause invasive disease, including bacteremia and meningitis, in immunocompromised patients. The aim of this study was to address characteristics and risk factors associated with meningitis by L. monocytogenes and to compare them with meningitis caused by other bacteria in SLE patients. 

Methods: We performed a retrospective cohort study in a tertiary care center in Mexico City between 2000 and 2015. SLE patients who had a cerebrospinal fluid (CSF) culture positive for L. monocytogenes or other gram-positive bacteria were included. All patients fulfilled at least 4 ACR criteria for SLE. We also analyzed patients without SLE with a positive CSF culture for L. monocytogenes. Patients with a clinical diagnosis of meningitis but without a positive CSF culture were excluded. Demographic, clinical and serologic features both 3 months before and at the infection were recorded.

Results:  Fourteen patients had a positive CSF culture for L. monocytogenes during the study period, and 9 of them (64%) had SLE. Among all SLE patients with meningitis proven by a positive CSF culture (n=22), infection with L. monocytogenes represented 41%. Group B streptococcus and S. pneumoniae were the second most common pathogens, each accounting for 14%.

There was no difference in SLEDAI score, complement and anti-dsDNA levels 3 months prior to the infection between both SLE groups. Prednisone and azathioprine dose 3 months before the infection were higher in patients with L. monocytogenes meningitis (p=0.025 and 0.043, respectively).

At the time of the infection, there was no difference in complement and antidsDNA levels; SLEDAI and SDI scores; prednisone, immunosuppressive and antimalarial drug dose; and CSF findings between both groups. Most SLE patients with L. monocytogenes received ampicillin (89%) during the first 24 hours after admission. SLE patients with L. monocytogenes had shorter stays in an intensive care unit (p=0.034) and lower mortality at 6 months (11 vs 54%, p=0.04) than those with meningitis by other bacteria. There was also a trend for lower mortality in patients with L. monocytogenes meningitis and SLE compared to those without SLE (11 vs 60%, p=0.052). 

Conclusion: This is the largest, single-center study regarding L. monocytogenes meningitis in SLE patients. L. monocytogenes was a common cause for meningitis in our cohort, and SLE patients seemed especially susceptible to this pathogen. Other immunosupressed patients (HIV, transplant recipients, chemotherapy, other rheumatologic diseases) are routinely treated at our institution and the incidence in those patients was clearly lower. Whether a specific immunologic defect predisposes SLE patients to L. monocytogenes remains to be determined. On the other hand, mortality and days in an intensive care unit were lower in SLE patients with L. monocytogenes, which could be related to the prompt initiation of appropriate antibiotic therapy. 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/meningitis-in-systemic-lupus-erythematosus-patients-epidemiologic-profile-of-listeria-monocytogenes-infection-a-single-center-study/