Spontaneous and post-surgical/traumatic Klebsiella pneumoniae meningitis: two distinct clinic-microbiological entities.

Objectives To analyze and compare the characteristics and outcome of spontaneous meningitis (SM) versus post-surgical/traumatic meningitis (PSTM) due to Klebsiella pneumoniae. Methods We conducted a retrospective, multicentric, cohort study of all K. pneumoniae meningitis cases managed between January 2007 and May 2018 in 7 university hospitals of Paris area. We further analyzed the microbiological characteristics of 16 available K. pneumoniae isolates, and sequenced the genome of 7 of them that were isolated from SM. Results Among 35 cases, 10 were SM, and 25 were PSTM. SM were more severe than PSTM with higher septic shock (p=0.004) and in-hospital mortality rates (p=0.004). In contrast, 5 patients from the PSTM group versus no patients from the SM group relapsed. All K. pneumoniae strains recovered from SM but none of those recovered from PSTM displayed hypervirulent phenotypic (positive string test) and genotypic (genes corresponding to capsular serotypes K1 or K2, virulence genes rmpA, iutA) characteristics (p<0.0001). PSTM tended to be more frequently polymicrobial (p=0.08) and caused by an extended-spectrum β-lactamase producing strain (p=0.08) than SM. Conclusions SM and PSTM are two entities differing both from a clinical and a microbiological standpoint. SM appears as a dreadful infection induced by hypervirulent K. pneumoniae strains.