Pathologic fracture and hardware failure in Streptococcus anginosus femoral osteomyelitis: Case report

Introduction: Pathologic fracture of the femur due to Streptococcus anginosus osteomyelitis has rarely been described. With limited evidence for treating S. anginosus osteomyelitis, the orthopaedic surgeon is presented with a difficult treatment decision at index presentation. Presented here is a case of failed conservative management, diagnostic dilemma, failed hardware stabilization, and definitive surgical treatment resulting in good clinical outcome. Case presentation: A 69-year-old male experienced acute right thigh pain, edema, and erythema after dental treatment 17 days prior. He was diagnosed with right femoral diaphyseal osteomyelitis and Brodie's abscess. Blood cultures grew S. anginosus, but all site-specific tissue cultures resulted negative. Initial management consisted of intravenous antibiotic therapy and percutaneous abscess drainage. Months later, the patient sustained a displaced pathologic fracture of the diaphyseal femur and there was concern for neoplasm, but biopsies were negative. Stabilization was attempted with a lateral plate and screws. This hardware catastrophically failed in the setting of an oligotrophic femoral nonunion. Ultimately, the patient was successfully treated with an intramedullary nail coated with antibiotic-impregnated cement. Twelve months later, the patient achieved clinical and radiographic healing with no evidence of relapse of his osteomyelitis. Clinical discussion: Conservative management of S. anginosus femoral osteomyelitis was inadequate and corroborates the existing literature. S. anginosus osteomyelitis and pyomyositis may be most optimally treated aggressively with early surgical intervention. Conclusion: Early surgical debridement and stabilization of the compromised bone with an antibiotic coated intramedullary nail following medullary reaming may prevent pathologic fracture, eradicate infection, and achieve predictable outcomes

siRNA-Mediated Silencing of <i>doublesex</i> during Female Development of the Dengue Vector Mosquito <i>Aedes aegypti</i>

<div><p>The development of sex-specific traits, including the female-specific ability to bite humans and vector disease, is critical for vector mosquito reproduction and pathogen transmission. Doublesex (Dsx), a terminal transcription factor in the sex determination pathway, is known to regulate sex-specific gene expression during development of the dengue fever vector mosquito <i>Aedes aegypti</i>. Here, the effects of developmental siRNA-mediated <i>dsx</i> silencing were assessed in adult females. Targeting of <i>dsx</i> during <i>A</i>. <i>aegypti</i> development resulted in decreased female wing size, a correlate for body size, which is typically larger in females. siRNA-mediated targeting of <i>dsx</i> also resulted in decreased length of the adult female proboscis. Although <i>dsx</i> silencing did not impact female membrane blood feeding or mating behavior in the laboratory, decreased fecundity and fertility correlated with decreased ovary length, ovariole length, and ovariole number in <i>dsx</i> knockdown females. Dsx silencing also resulted in disruption of olfactory system development, as evidenced by reduced length of the female antenna and maxillary palp and the sensilla present on these structures, as well as disrupted odorant receptor expression. Female lifespan, a critical component of the ability of <i>A</i>. <i>aegypti</i> to transmit pathogens, was also significantly reduced in adult females following developmental targeting of <i>dsx</i>. The results of this investigation demonstrate that silencing of <i>dsx</i> during <i>A</i>. <i>aegypti</i> development disrupts multiple sex-specific morphological, physiological, and behavioral traits of adult females, a number of which are directly or indirectly linked to mosquito reproduction and pathogen transmission. Moreover, the olfactory phenotypes observed connect Dsx to development of the olfactory system, suggesting tha<i>t A</i>. <i>aegypti</i> will be an excellent system in which to further assess the developmental genetics of sex-specific chemosensation.</p></div

Decreased female fertility and fecundity is observed following developmental silencing of <i>dsx</i>.

<p>Although the percentages of <i>dsx-KD A</i>, <i>dsx-KD B</i>, and control siRNA-microinjected adult females that mated (A) or took blood meals (B) did not significantly differ, adult females that were injected with <i>dsx-KD A</i> or <i>dsx-KD B</i> siRNA as pupae had decreased fecundity (C) and fertility (D). Means for each control or experimental group are reported, and these were determined through the combination of data gathered in at least three biological replicate experiments. Error bars represent standard deviations.** = P < 0.01; *** = P < 0.001.</p

Sensillar defects result from silencing of <i>dsx</i>.

<p>Antennal <i>sTrichodea</i> (inset in C) are found on the adult female <i>A</i>. <i>aegypti</i> antenna (control-injected animal shown in A), while <i>sBasiconica</i> (inset in D) are observed on the adult female maxillary palp (control-injected animal shown in B). With respect to control-injected adult females, adult females that were injected with <i>dsx-KD A</i> or <i>dsx-KD B</i> siRNA as pupae had significantly shorter antennal <i>sTrichodea</i> (C) and maxillary palp <i>sBasiconica</i> (D). Mean sensillar lengths for each control or experimental condition are reported, and these were determined through the combination of data gathered in at least two biological replicate experiments. Error bars represent standard deviations. *** = P < 0.001.</p

Adult female lifespan decreases following developmental silencing of <i>dsx</i>.

<p>Survivorship curves for animals injected as pupae with control, <i>dsx-KD A</i>, or <i>dsx-KD B</i> siRNA are shown. Analysis of data combined from three replicate experiments indicated that in comparison to the control, life span was significantly decreased in individuals injected with <i>dsx-KD A</i> (P<0.001) or <i>dsx-KD B</i> (P<0.001) siRNA.</p

Multiple ovary phenotypes are observed following developmental silencing of <i>dsx</i>.

<p>Adult females that were injected with <i>dsx-KD A</i> or <i>dsx-KD B</i> siRNA as pupae had decreased ovary length both pre- (A) and post-blood meals (B). Representative ovaries from control-, <i>dsx-KD A</i>, or <i>dsx-KD B</i> stained with phalloidin (red) and the nuclear marker TO-PRO-3 (blue) are shown below each graph in A and B. In comparison to control microinjected females, the number of ovarioles/ovary (E) and length of each ovariole (F) post-blood meal was significantly less in females microinjected with <i>dsx-KD A</i> and <i>dsx-KD B</i> siRNA. Means for each control or experimental group are reported, and these were determined through the combination of data gathered in at least three biological replicate experiments. Error bars represent standard deviations. *** = P < 0.001.</p

Adult survival following larval targeting of <i>dsx</i>.

<p>Shown are the numbers and percentages of adult females and males that were observed following chitosan/siRNA feedings of 50 animals with control, <i>dsx</i>-KD A, or <i>dsx</i>-KD B siRNA in four replicate experiments (I-IV). No significant differences were observed in the percentages of adults, adult females, or adult males surviving following each treatment.</p><p>Adult survival following larval targeting of <i>dsx</i>.</p

Dsx regulates <i>OR</i> expression.

<p>Terminal segments of adult female antennae oriented distal upward that were hybridized with <i>OR 62</i> (A, B, C), <i>OR 123</i> (D, E, F), <i>OR 2</i> (G, H, I), or <i>OR 9</i> (J, K, L) riboprobes (green, at left in each panel) are shown. Antennae were counter-stained with anti-Tubulin (red, center of each panel) and TO-PRO-3 nuclear stain (blue in overlays at right in each panel). <i>OR 62</i> (A), <i>OR 123</i> (D), <i>OR 2</i> (G), and <i>OR 9</i> transcripts are detected in ORNs of control-injected adult female antennae (A, D, G, J). Little expression of these transcripts could be detected in adult females injected with <i>dsx-KD A</i> (B, E, H, K) or <i>dsx-KD B</i> (C, F, I, J) siRNA as pupae. Representative results from a total of 24 antennae stained in two separate replicate experiments are shown, and analysis of <i>OR</i> expression intensity levels is presented in <a href="http://www.plosntds.org/article/info:doi/10.1371/journal.pntd.0004213#pntd.0004213.s004" target="_blank">S3 Table</a>. Scale bars = 25 microns. Arrowheads mark ORNs.</p

Developmental silencing of <i>dsx</i> decreases adult female appendage size.

<p>With respect to adult females fed control siRNA nanoparticles as larvae, mean adult wing areas (A), as well as mean adult wing (B), proboscis (C), antenna (D), and maxillary palp (E) lengths are significantly decreased in females fed <i>dsx-KD A</i> or <i>dsx-KD B</i> siRNA nanoparticles as larvae. Means for each control or experimental group are reported, and these were determined through the combination of data gathered in at least four biological replicate experiments. Error bars represent standard deviations. *** = P < 0.001.</p