How Many Imaging Studies Do Patients With Neuromuscular Early Onset Scoliosis (EOS) Receive?

BACKGROUND: Children with neuromuscular early onset scoliosis (EOS) receive numerous radiographic studies both from orthopaedic and other specialties. Ionizing radiation doses delivered by computed tomography (CT) are reportedly 100 times higher than conventional radiography. The purpose of this study was to evaluate the number of radiographic studies ordered for neuromuscular EOS patients during their care. METHODS: Retrospective review at a tertiary children's hospital from January 2010 to June 2021 included all patients with neuromuscular EOS followed by an orthopaedic specialist for a minimum of 3 years. Patients were excluded if the majority of their nonorthopaedic care was provided by outside institutions. RESULTS: Eighteen patients met inclusion criteria with mean follow up of 6.4±2.3 years. A total of 1312 plain radiographs and 35 CT scans were performed. Of the plain radiographs, 34.7% were ordered by orthopaedic providers and 65.3% (857/1312) were ordered by other providers. Of the CT scans, 4 were ordered by orthopaedic providers, while 88.5% (21/35) were ordered by other providers. An average of 74.7 (range: 29 to 124) radiographs and 1.9 (range: 0 to 9) CT scans ordered over the course of each patient's treatment for an average of 13.0±6.0 radiographs and 0.3 CT scans per year. CONCLUSIONS: With an average of 75 radiographs and 1.9 CT scans performed per patient, consideration for steps to limit exposure to ionizing radiation should be made a particularly high priority in this unique subset of patients. This requires interdisciplinary coordination as 65% of the radiographs and over 80% of the CT scans were ordered by nonorthopaedic providers. LEVEL OF EVIDENCE: Level III.

The Versatile Pseudomonas aeruginosa Biofilm Matrix Protein CdrA Promotes Aggregation through Different Extracellular Exopolysaccharide Interactions.

Pseudomonas aeruginosa is an important pathogen that causes chronic infections that involve multicellular aggregates called biofilms. Within biofilms, bacteria are surrounded in a protective extracellular matrix of proteins, exopolysaccharides (EPS), and DNA. A key P. aeruginosa matrix protein is an extracellular adhesin called CdrA, which promotes aggregation by binding to the EPS Psl and via CdrA-CdrA interactions. We hypothesized that because of its ability to bind Psl, CdrA would be important only for strains that use Psl as the primary EPS (e.g., the laboratory strain PAO1). Thus, we predicted that cdrA might be dispensable for biofilm formation by strains that do not utilize Psl (e.g., the laboratory strain PA14). Instead, we observed that cdrA deletion strains exhibited biofilm defects, regardless of their EPS dependencies. We screened a panel of clinical and environmental P. aeruginosa isolates for the presence of the cdrA allele and production of CdrA protein. All isolates that we tested contained the cdrA allele, and these alleles had minimal sequence variation compared to the reference PAO1 cdrA gene. Additionally, all isolates except one produced detectable CdrA protein. We investigated the possible mechanisms of CdrA-promoted biofilm formation in these strains where Psl is not dominant, and we discovered that CdrA binds to Pel. Although Psl and Pel chemical structures are distinct, this appears to be a specific interaction, since previous work has shown that CdrA binds discriminately to other EPS. Our findings provide new understanding of biofilm formation across P. aeruginosa isolates and emphasize the versatility of CdrA.IMPORTANCE Depending upon the strain, Pseudomonas aeruginosa can use different exopolysaccharides (e.g., Psl, Pel, and alginate) to build its biofilm matrix. Previously, we demonstrated that the biofilm matrix protein CdrA binds to Psl, promoting biofilm formation and aggregate stability. As such, it was thought that CdrA might be important for biofilm assembly only in strains that rely upon Psl. However, past studies indicated that CdrA can interact with monosaccharides not present in Psl, including N-acetylglucosamine, a constituent of another EPS called Pel. We discovered that CdrA also binds to Pel and promotes biofilm formation by strains in which Psl is not dominant. Thus, our findings suggest that CdrA plays a common role as a biofilm matrix cross-linker across P. aeruginosa isolates with different EPS.

CdrA Interactions within the Pseudomonas aeruginosa Biofilm Matrix Safeguard It from Proteolysis and Promote Cellular Packing.

Biofilms are robust multicellular aggregates of bacteria that are encased in an extracellular matrix. Different bacterial species have been shown to use a range of biopolymers to build their matrices. Pseudomonas aeruginosa is a model organism for the laboratory study of biofilms, and past work has suggested that exopolysaccharides are a required matrix component. However, we found that expression of the matrix protein CdrA, in the absence of biofilm exopolysaccharides, allowed biofilm formation through the production of a CdrA-rich proteinaceous matrix. This represents a novel function for CdrA. Similar observations have been made for other species such as Escherichia coli and Staphylococcus aureus, which can utilize protein-dominant biofilm matrices. However, we found that these CdrA-containing matrices were susceptible to both exogenous and self-produced proteases. We previously reported that CdrA directly binds the biofilm matrix exopolysaccharide Psl. Now we have found that when CdrA bound to Psl, it was protected from proteolysis. Together, these results support the idea of the importance of multibiomolecular components in matrix stability and led us to propose a model in which CdrA-CdrA interactions can enhance cell-cell packing in an aggregate that is resistant to physical shear, while Psl-CdrA interactions enhance aggregate integrity in the presence of self-produced and exogenous proteases.IMPORTANCEPseudomonas aeruginosa forms multicellular aggregates or biofilms using both exopolysaccharides and the CdrA matrix adhesin. We showed for the first time that P. aeruginosa can use CdrA to build biofilms that do not require known matrix exopolysaccharides. It is appreciated that biofilm growth is protective against environmental assaults. However, little is known about how the interactions between individual matrix components aid in this protection. We found that interactions between CdrA and the exopolysaccharide Psl fortify the matrix by preventing CdrA proteolysis. When both components-CdrA and Psl-are part of the matrix, robust aggregates form that are tightly packed and protease resistant. These findings provide insight into how biofilms persist in protease-rich host environments.