Pediatric Lumbosacral Spondylolisthesis: Overcoming the Disability!

BACKGROUND: Congenital spondylolisthesis is characterized by dysplasia of the facet joint or congenital defect in the pars. OBJECTIVE: Our study highlights the clinical and radiological profile, various treatment options, and outcomes in patients with pediatric congenital lumbar and lumbosacral spondylolisthesis. METHODS: A retrospective analysis and follow-up of 22 patients were conducted presented with radiological diagnosis of congenital lumbar/lumbosacral spondylolisthesis (2018-2021). RESULTS: Twenty patients (91%) had L5-S1 listhesis and two patients (9%) had L4-L5 listhesis. Six (27.3%) patients had low-grade listhesis (grades 1-2), 16 (72.7%) had high-grade listhesis (grades 3-5). Seventeen (77.3%) had S1, three (13.6%) had L5, and two (9%) had both L4-L5 radiculopathy. All patients had neurogenic claudication. One had an associated spina bifida occulta. Six (27.3%) patients underwent two-level fixation, and 16 (72.7%) underwent three-level fixation. Minimally Invasive Transforaminal Lumbar Interbody Fusion (MIS TLIF) was done in two patients. Revision of at least one screw was done in three patients. After one year of follow-up, all the patients had 75-100% relief in radicular pain and neurogenic claudication. The Oswestry Disability Index (ODI) score in preop for all patients was 41-60% and postoperatively they showed an improvement in ODI score (0-20). The postoperative low back pain score on the Numeric Rating Scale was 0-1 for all patients. CONCLUSION: Congenital lumbar spondylolisthesis usually presents with high-grade listhesis. Management of such cases is a surgical challenge but posterior decompression resulted in relief of pain in all patients. However, in situ fixation without reduction is also effective in selective cases where attempts to reduce the listhesis result in a decline in intraoperative neuromonitoring parameters.

Impact of Polymicrobial Infection on Fitness of Streptococcus gordonii In Vivo.

Pathogenic microbial ecosystems are often polymicrobial, and interbacterial interactions drive emergent properties of these communities. In the oral cavity, Streptococcus gordonii is a foundational species in the development of plaque biofilms, which can contribute to periodontal disease and, after gaining access to the bloodstream, target remote sites such as heart valves. Here, we used a transposon sequencing (Tn-Seq) library of S. gordonii to identify genes that influence fitness in a murine abscess model, both as a monoinfection and as a coinfection with an oral partner species, Porphyromonas gingivalis. In the context of a monoinfection, conditionally essential genes were widely distributed among functional pathways. Coinfection with P. gingivalis almost completely changed the nature of in vivo gene essentiality. Community-dependent essential (CoDE) genes under the coinfection condition were primarily related to DNA replication, transcription, and translation, indicating that robust growth and replication are required to survive with P. gingivalis in vivo. Interestingly, a group of genes in an operon encoding streptococcal receptor polysaccharide (RPS) were associated with decreased fitness of S. gordonii in a coinfection with P. gingivalis. Individual deletion of two of these genes (SGO_2020 and SGO_2024) resulted in the loss of RPS production by S. gordonii and increased susceptibility to killing by neutrophils. P. gingivalis protected the RPS mutants by inhibiting neutrophil recruitment, degranulation, and neutrophil extracellular trap (NET) formation. These results provide insight into genes and functions that are important for S. gordonii survival in vivo and the nature of polymicrobial synergy with P. gingivalis. Furthermore, we show that RPS-mediated immune protection in S. gordonii is dispensable and detrimental in the presence of a synergistic partner species that can interfere with neutrophil killing mechanisms. IMPORTANCE Bacteria responsible for diseases originating at oral mucosal membranes assemble into polymicrobial communities. However, we know little regarding the fitness determinants of the organisms that initiate community formation. Here, we show that the extracellular polysaccharide of Streptococcus gordonii, while important for streptococcal survival as a monoinfection, is detrimental to survival in the context of a coinfection with Porphyromonas gingivalis. We found that the presence of P. gingivalis compensates for immune protective functions of extracellular polysaccharide, rendering production unnecessary. The results show that fitness determinants of bacteria in communities differ substantially from those of individual species in isolation. Furthermore, constituents of communities can undertake activities that relieve the burden of energetically costly biosynthetic reactions on partner species.

Clp ATPases differentially affect natural competence development in Streptococcus mutans.

In naturally competent bacteria, DNA transformation through horizontal gene transfer is an evolutionary mechanism to receive extracellular DNA. Bacteria need to maintain a state of competence to accept foreign DNA, and this is an energy-driven phenomenon that is tightly controlled. In Streptococcus, competence development is a complex process that is not fully understood. In this study, we used Streptococcus mutans, an oral bacterium, to determine how cell density affects competence development. We found that in S. mutans the transformation efficiency is maximum when the transforming DNA was added at low cell density and incubated for 2.5 h before selecting for transformants. We also found that S. mutans cells remain competent until the mid-logarithmic phase, after which the competence decreases drastically. Surprisingly, we observed that individual components of Clp proteolytic complexes differentially regulate competence. If the transformation is carried out at the early growth phase, both ClpP protease and ClpX ATPase are needed for competence. In contrast, we found that both ClpC and ClpE negatively affect competence. We also found that if the transformation is carried out at the mid-logarithmic growth phase ClpX is still required for competence, but ClpP negatively affects competence. While the exact reason for this differential effect of ClpP and ClpX on transformation is currently unknown, we found that both ClpC and ClpE have a negative effect on transformation, which was not reported before.