Venous thrombosis associated with staphylococcal osteomyelitis in children

Risk Factors for Venous Thromboembolic Events in Children With Acute Musculoskeletal Infections

BACKGROUND AND OBJECTIVES

Venous thromboembolic events (VTE) complicate acute hematogenous musculoskeletal infections (MSKIs) among hospitalized children. However, there is limited guidance for which specific MSKI patients are at the greatest VTE risk. This study aimed to identify VTE risk factors for children hospitalized with MSKIs.

METHODS

A retrospective chart review was performed of children hospitalized with MSKIs at a single quaternary care pediatric hospital during a 9-year period. Patients with chronic MSKIs, non-hematogenous infections, or significant contributing comorbidities were excluded. Demographic and clinical characteristics were compared between patients with and without VTE using forward stepwise conditional multivariable logistic regression to identify VTE risk factors.

RESULTS

Among 335 included patients, 7 (2.1%) developed a VTE. There was no difference in age, sex, or obesity rates for those with or without VTE. Patients with methicillin-resistant Staphylococcus aureus (MRSA) infections and/or critical illness were more likely to develop a VTE with summative adjusted odds ratios of 31.7 and 26.4, respectively. In addition, patients with VTEs had longer hospitalizations (median 4.7 vs. 12.8 d, P <0.001), longer courses of intravenous antimicrobials (median 3.7 vs. 13.5 d, P =0.001), and longer time to fever resolution (median 25.7 vs. 162 h, P =0.004).

CONCLUSIONS

VTE prevalence among children with acute MSKIs is low. MRSA infection and critical illness significantly increase the risk for VTE development in these patients. Future prospective studies are needed to determine if VTEs in high-risk MSKI patients can be prevented.

Pediatric Swine Model of Methicillin-Resistant Staphylococcus aureus Sepsis-Induced Coagulopathy, Disseminated Microvascular Thrombosis, and Organ Injuries

Sepsis-induced coagulopathy leading to disseminated microvascular thrombosis is associated with high mortality and has no existing therapy. Despite the high prevalence of Gram-positive bacterial sepsis, especially methicillin-resistant Staphylococcus aureus (MRSA), there is a paucity of published Gram-positive pediatric sepsis models. Large animal models replicating sepsis-induced coagulopathy are needed to test new therapeutics before human clinical trials.

HYPOTHESIS

Our objective is to develop a pediatric sepsis-induced coagulopathy swine model that last 70 hours.

METHODS AND MODELS

Ten 3 weeks old piglets, implanted with telemetry devices for continuous hemodynamic monitoring, were IV injected with MRSA (n = 6) (USA300, Texas Children's Hospital 1516 strain) at 1 × 10⁹ colony forming units/kg or saline (n = 4). Fluid resuscitation was given for heart rate greater than 50% or mean arterial blood pressure less than 30% from baseline. Acetaminophen and dextrose were provided as indicated. Point-of-care complete blood count, prothrombin time (PT), activated thromboplastin time, d-dimer, fibrinogen, and specialized coagulation assays were performed at pre- and post-injection, at 0, 24, 48, 60, and 70 hours. Piglets were euthanized and necropsies performed.

RESULTS

Compared with the saline treated piglets (control), the septic piglets within 24 hours had significantly lower neurologic and respiratory scores. Over time, PT, d-dimer, and fibrinogen increased, while platelet counts and activities of factors V, VII, protein C, antithrombin, and a disintegrin and metalloproteinase with thrombospondin-1 motifs (13th member of the family) (ADAMTS-13) decreased significantly in septic piglets compared with control. Histopathologic examination showed minor focal organ injuries including microvascular thrombi and necrosis in the kidney and liver of septic piglets.

INTERPRETATIONS AND CONCLUSIONS

We established a 70-hour swine model of MRSA sepsis-induced coagulopathy with signs of consumptive coagulopathy, disseminated microvascular thrombosis, and early organ injuries with histological minor focal organ injuries. This model is clinically relevant to pediatric sepsis and can be used to study dysregulated host immune response and coagulopathy to infection, identify potential early biomarkers, and to test new therapeutics.

Predictive Factors to Guide Empiric Antimicrobial Therapy of Acute Hematogenous Osteomyelitis in Children

BACKGROUND

Acute hematogenous osteomyelitis (AHO) is a serious infection in children. Pediatric Infectious Diseases Society guidelines recommend empiric methicillin-resistant Staphylococcus aureus (MRSA) therapy in regions where MRSA accounts for more than 10-20% of all staphylococcal osteomyelitis. We sought to examine factors present at the time of admission which may predict etiology and guide empiric treatment for pediatric AHO in a region with endemic MRSA.

METHODS

We reviewed admissions with International Classification of Diseases 9/10 codes for AHO from 2011 to 2020 in otherwise healthy children. Medical records were reviewed for clinical and laboratory parameters present on the day of admission. Logistic regression was used to determine clinical variables independently associated with (1) MRSA infection and (2) non-Staphylococcus aureus infection.

RESULTS

A total of 545 cases were included. An organism was identified in 77.1% of cases and S. aureus was the most common (66.2%); 18.9% of all AHO cases were MRSA. Organisms besides S. aureus were identified in 10.8% of cases. CRP >7 mg/dL, subperiosteal abscess, history of any prior skin or soft tissue infection (SSTI) and need for intensive care unit admission were independently associated with MRSA infection. Vancomycin was used as an empiric treatment in 57.6% of cases. If the above criteria were relied upon to predict MRSA AHO, empiric vancomycin use could have been reduced by 25%.

CONCLUSIONS

Critical illness, CRP >7 mg/dL at the time of presentation, subperiosteal abscess and history of SSTI are suggestive of MRSA AHO, and could be considered when planning empiric therapy. Further work is needed to validate these findings before wider implementation.

Management and Prevention of Staphylococcus aureus Infections in Children

Staphylococcus aureus is a common skin commensal with the potential to cause severe infections resulting in significant morbidity and mortality. Up to 30% of individuals are colonized with S aureus, though infection typically does not occur without skin barrier disruption. Infection management includes promptly addressing the source of infection, including sites of metastatic infection, and initiation of effective antibiotics, which should be selected based on local antibiotic susceptibility patterns. Given that S aureus colonization is a risk factor for infection, preventive strategies are aimed at optimizing hygiene measures and decolonization regimens for outpatients and critically ill children with prolonged hospitalizations.

Septicaemia with deep venous thrombosis and necrotising pneumonia caused by acute community-acquired methicillin-resistant Staphylococcus aureus in an infant with a three-year follow-up: a case report

BACKGROUND

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) is a common pathogen that usually causes bacteraemia, osteomyelitis, as well as skin and soft tissue infections. However, deep venous thrombosis (DVT) and necrotising pneumonia are rare in infants.

CASE PRESENTATION

We report the case of a one-month-five-day-old girl who was hospitalised for DVT and necrotising pneumonia due to septicaemia associated with Staphylococcus aureus. She recovered after treatment with intravenous antibiotics and multiple anticoagulant therapy, but DVT persisted at the three-year follow-up. Collateral circulation around the DVT was well-formed. Post thrombotic syndrome was not observed.

CONCLUSIONS

Staphylococcus aureus complicated by DVT and necrotising pneumonia is rare and can be successfully treated.

Acute Multifocal Nonhematogenous Methicillin-Sensitive Staphylococcus aureus Osteomyelitis in a Healthy Adolescent: An Atypical Presentation

Osteomyelitis represents inflammation and infection of bone tissue by a pathogen. Acute osteomyelitis is more likely to be unifocal compared to a chronic process which tends to be multifocal and recurrent. Early diagnosis, aggressive appropriate antibiotic therapy and a multidisciplinary approach are essential for a satisfactory prognosis and improved outcome. We report an atypical case of acute multifocal methicillin-sensitive Staphylococcus aureus (MSSA) osteomyelitis.

Chronic Osteomyelitis of Long Bones: Imaging Pearls and Pitfalls in Pediatrics

Chronic bacterial osteomyelitis is characterized by progressive inflammatory bone destruction and apposition of new bone most often caused by pyogenic bacteria. Clinical findings are nonspecific, and serum inflammatory markers can be normal. Prompt diagnosis and treatment are essential. Left untreated, chronic infection can lead to high morbidity and mortality. Imaging's major role is to suggest the correct diagnosis, exclude other diagnoses that can mimic osteomyelitis, document extent of disease, and guide interventions such as image-guided biopsy or surgical debridement. Several conditions can mimic chronic osteomyelitis clinically and radiographically. The main differential diagnoses include an oncologic process, chronic nonbacterial or chronic recurrent multifocal osteomyelitis, bone infarct in sickle cell disease, osteoid osteoma, and stress reaction/fracture. The oncologic process to consider includes metastatic neuroblastoma and Langerhans cell histiocytosis in a child younger than five years or leukemia, Ewing sarcoma, and osteosarcoma in the older age group. However, these lesions can typically be excluded based on radiographs and magnetic resonance imaging findings. Therefore, radiologist familiarity with imaging findings and mimickers is essential. In this article, we briefly review the epidemiologic, clinical, and histopathologic features of chronic bacterial osteomyelitis and emphasize imaging pearls and pitfalls, with discussion of the most common differential diagnoses.

OUP accepted manuscript

Background

Combination antibiotic therapy with an antitoxin agent, such as clindamycin, is included in some guidelines for severe, toxin-mediated Staphylococcus aureus infections. The evidence to support this practice is currently limited to in vitro, animal and observational human case-series data, with no previous randomized controlled trials (RCTs).

Objectives

This pilot RCT aimed to determine the feasibility of conducting a clinical trial to examine if adjunctive clindamycin with standard therapy has greater efficacy than standard therapy alone for S. aureus infections.

Methods

We performed an investigator-initiated, open-label, multicentre, pilot RCT (ACTRN12617001416381p) in adults and children with severe S. aureus infections, randomized to standard antibiotic therapy with or without clindamycin for 7 days.

Results

Over 28 months, across nine sites, 127 individuals were screened and 34 randomized, including 11 children (32%). The primary outcome—number of days alive and free of systemic inflammatory response syndrome ≤14 days—was similar between groups: clindamycin (3 days [IQR 1–6]) versus standard therapy (4 days [IQR 0–8]). The 90 day mortality was 0% (0/17) in the clindamycin group versus 24% (4/17) in the standard therapy group. Secondary outcomes—microbiological relapse, treatment failure or diarrhoea—were similar between groups.

Conclusions

As the first clinical trial assessing adjunctive clindamycin for S. aureus infections, this study indicates feasibility and that adults and children can be incorporated into one trial using harmonized endpoints, and there were no safety concerns. The CASSETTE trial will inform the definitive S. aureus Network Adaptive Platform (SNAP) trial, which includes an adjunctive clindamycin domain and participants with non-severe disease.

Clinical Practice Guideline by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America: 2021 Guideline on Diagnosis and Management of Acute Hematogenous Osteomyelitis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute hematogenous osteomyelitis (AHO) in children was developed by a multidisciplinary panel representing Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA). This guideline is intended for use by healthcare professionals who care for children with AHO, including specialists in pediatric infectious diseases, orthopedics, emergency care physicians, hospitalists, and any clinicians and healthcare providers caring for these patients. The panel's recommendations for the diagnosis and treatment of AHO are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of AHO in children. The panel followed a systematic process used in the development of other IDSA and PIDS clinical practice guidelines, which included a standardized methodology for rating the certainty of the evidence and strength of recommendation using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. A detailed description of background, methods, evidence summary and rationale that support each recommendation, and knowledge gaps can be found online in the full text.

[Acute osteomyelitis caused by community-acquired methicillin-resistant Staphylococcus aureus in children: about 15 cases]

La prise en charge de l´ostéomyélite aiguë devient plus délicate depuis l´émergence du Staphylocoque aureus résistant à la méthicilline d´origine communautaire. Nous avons recueilli les cas d´ostéomyélite aiguë dues à ce germe sur une période de 21 ans (Janvier 1995-Décembre 2016) et nous avons essayé d´analyser les particularités de cette entité pathologique. Notre série comporte 15 enfants, d´âge moyen 9 ans. Le membre inférieur était atteint dans tous les cas. Une notion de traumatisme local a été signalée dans 8 cas et une porte d´entrée cutanée a été trouvée dans 4 cas. Le mode de début était aigu dans 12 cas avec un tableau de pseudo-paralysie du membre atteint. Une staphylococcie pulmonaire avec des signes septico-pyohémiques ont été notés dans un cas. L´hémoculture était positive dans 8 cas. La recherche par PCR de la leucocidine de Panton et Valentine était pratiquée dans 1 cas avec un résultat positif. Tous ces patients ont eu un débridement chirurgical et une antibiothérapie empirique secondairement adaptée. L´évolution était bonne dans 8 cas et mauvaise dans les autres cas avec passage à la chronicité dans 6 cas et un cas de décès. Une fracture pathologique a été signalée dans 3 cas. La survenue d´une ostéomyélite à Staphylocoque aureus résistant à la méthicilline d´origine communautaire est péjorative. Connaitre ces infections en se basant sur des arguments cliniques et paracliniques est un enjeu important pour une prise en charge thérapeutique spécifique et rapide.

Evaluation of a bone filler scaffold for local antibiotic delivery to prevent Staphylococcus aureus infection in a contaminated bone defect

We previously reported the development of an osteogenic bone filler scaffold consisting of degradable polyurethane, hydroxyapatite, and decellularized bovine bone particles. The current study was aimed at evaluating the use of this scaffold as a means of local antibiotic delivery to prevent infection in a bone defect contaminated with Staphylococcus aureus. We evaluated two scaffold formulations with the same component ratios but differing overall porosity and surface area. Studies with vancomycin, daptomycin, and gentamicin confirmed that antibiotic uptake was concentration dependent and that increased porosity correlated with increased uptake and prolonged antibiotic release. We also demonstrate that vancomycin can be passively loaded into either formulation in sufficient concentration to prevent infection in a rabbit model of a contaminated segmental bone defect. Moreover, even in those few cases in which complete eradication was not achieved, the number of viable bacteria in the bone was significantly reduced by treatment and there was no radiographic evidence of osteomyelitis. Radiographs and microcomputed tomography (µCT) analysis from the in vivo studies also suggested that the addition of vancomycin did not have any significant effect on the scaffold itself. These results demonstrate the potential utility of our bone regeneration scaffold for local antibiotic delivery to prevent infection in contaminated bone defects.

Acute Hematogenous Osteomyelitis in Children: Clinical Presentation and Management

Acute hematogenous osteomyelitis (AHO) is a common invasive infection encountered in the pediatric population. In addition to the acute illness, AHO has the potential to create long-term morbidity and functional limitations. While a number of pathogens may cause AHO, Staphylococcus aureus is the most common organism identified. Despite the frequency of this illness, little high-quality data exist to guide providers in the care of these patients. The literature is reviewed regarding the epidemiology, microbiology and management of AHO in children. A framework for empiric therapy is provided drawing from the available literature and published guidelines.

Osteomyelitis, Venous Thrombosis, and Septic Emboli in a Pediatric Patient: A Case Report

New virulence factors, such as the Panton-Valentine leukocidin (PVL), are appearing during Staphylococcus aureus infections occurring in the pediatric population. Such factors increase the aggressiveness and risk of dissemination of the bacteria, causing infections to be life-threatening. An early diagnosis is thus especially important. We present a case of osteomyelitis, venous thrombosis, and septic emboli occurring in a pediatric patient that should trigger suspicion of a PVL-positive strain. A multidisciplinary approach is necessary to enable rapid diagnosis and early treatment, which is essential for successful management of these infections. Management is based on broad-spectrum antibiotics, in combination with aggressive surgical treatment and antithrombotic therapy. In patients infected with S. aureus whose condition worsens quickly, PVL gene sequencing should be considered.

The role of the msaABCR operon in implant-associated chronic osteomyelitis in Staphylococcus aureus USA300 LAC

BACKGROUND

The msaABCR operon regulates several staphylococcal phenotypes such as biofilm formation, capsule production, protease production, pigmentation, antibiotic resistance, and persister cells formation. The msaABCR operon is required for maintaining the cell wall integrity via affecting peptidoglycan cross-linking. The msaABCR operon also plays a role in oxidative stress defense mechanism, which is required to facilitate persistent and recurrent staphylococcal infections. Staphylococcus aureus is the most frequent cause of chronic implant-associated osteomyelitis (OM). The CA-MRSA USA300 strains are predominant in the United States and cause severe infections, including bone and joint infections.

RESULTS

The USA300 LAC strain caused significant bone damage, as evidenced by the presence of severe bone necrosis with multiple foci of sequestra and large numbers of multinucleated osteoclasts. Intraosseous survival and biofilm formation on the K-wires by USA300 LAC strains was pronounced. However, the msaABCR deletion mutant was attenuated. We observed minimal bone necrosis, with no evidence of intramedullary abscess and/or fibrosis, along reduced intraosseous bacterial population and significantly less biofilm formation on the K-wires by the msaABCR mutant. microCT analysis of infected bone showed significant bone loss and damage in the USA300 LAC and complemented strain, whereas the msaABCR mutant's effect was reduced. In addition, we observed increased osteoblasts response and new bone formation around the K-wires in the bone infected by the msaABCR mutant. Whole-cell proteomics analysis of msaABCR mutant cells showed significant downregulation of proteins, cell adhesion factors, and virulence factors that interact with osteoblasts and are associated with chronic OM caused by S. aureus.

CONCLUSION

This study showed that deletion of msaABCR operon in USA300 LAC strain lead to defective biofilm in K-wire implants, decreased intraosseous survival, and reduced cortical bone destruction. Thus, msaABCR plays a role in implant-associated chronic osteomyelitis by regulating extracellular proteases, cell adhesions factors and virulence factors. However additional studies are required to further define the contribution of msaABCR-regulated molecules in osteomyelitis pathogenesis.

Panton-Valentine leukocidin-positive novel sequence type 5959 community-acquired methicillin-resistant Staphylococcus aureus meningitis complicated by cerebral infarction in a 1-month-old infant

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a pathogen of major importance in pediatric patients. CA-MRSA can cause skin and soft tissue infection in children and young active adults with no predisposing factors, and life-threatening infections such as meningitis or necrotizing pneumonia have been reported. We report here a case of CA-MRSA meningitis complicated by acute left middle cerebral artery (MCA) infarction and necrotizing pneumonia in a previously healthy 1-month-old Vietnamese boy. He was firstly treated with vancomycin, but changed to linezolid because of persistent fever and low vancomycin trough level. He recovered successfully with residual right-sided hemiparesis. The mode of transmission of CA-MRSA and the mechanism of cerebral infarction (thrombotic or embolic) were unknown. The isolate was genotyped as staphylococcal cassette chromosome (SCC) mec type V with a novel sequence type (ST) 5959 harboring the Panton-Valentine leukocidin (PVL) gene. ST 5959 is a double locus variant of ST 59, which is a major PVL-positive CA-MRSA strain isolated in invasive disease in Asian countries. This case report may serve as a warning about the dissemination of PVL-positive CA-MRSA in and around Japan, with the possibility of causing serious life-threatening disease. The potential of linezolid for the treatment of MRSA meningitis as one of the alternative MRSA therapeutic drugs is also discussed.

Amoxicillin-Clavulanic Acid Empirical Oral Therapy for the Management of Children with Acute Haematogenous Osteomyelitis

According to the Guidelines of the European Society of Pediatric Infectious Diseases (ESPID), in low methicillin-resistant Staphylococcus aureus (MRSA) prevalence settings, short intravenous therapy is recommended in uncomplicated cases of acute haematogenous osteomyelitis (AHOM), followed by empirical oral therapy, preferentially with first/second-generation cephalosporin or dicloxacillin or flucloxacillin. However, several practical issues may arise using some of the first-line antibiotics such as poor palatability or adherence problems. Clinical, laboratory and therapeutic data from children with AHOM hospitalized in one Italian Paediatric Hospital between 2010 and 2019 were retrospectively collected and analyzed. The aim of the study was to highlight the extent of the use and the possible role of amoxicillin-clavulanic acid in the oral treatment of children with AHOM. Two hundred and ten children were included. S.aureus was identified in 42/58 children (72.4% of identified bacteria); 2/42 S.aureus isolates were MRSA (4.8%). No Kingella kingae was identified. Amoxicillin-clavulanic acid was the most commonly used oral drug (60.1%; n = 107/178) and it was associated with clinical cure in all treated children. Overall, four children developed sequelae. One (0.9%) sequela occurred among the 107 children treated with amoxicillin-clavulanic acid. Our results suggest that amoxicillin-clavulanic acid might be an option for oral antibiotic therapy in children with AHOM.

Update on Acute Bone and Joint Infections in Paediatrics: A Narrative Review on the Most Recent Evidence-Based Recommendations and Appropriate Antinfective Therapy

Acute bone and joint infections (BJIs) in children may clinically occur as osteomyelitis (OM) or septic arthritis (SA). In clinical practice, one-third of cases present a combination of both conditions. BJIs are usually caused by the haematogenous dissemination of septic emboli carried to the terminal blood vessels of bone and joints from distant infectious processes during transient bacteraemia. Early diagnosis is the cornerstone for the successful management of BJI, but it is still a challenge for paediatricians, particularly due to its nonspecific clinical presentation and to the poor specificity of the laboratory and imaging first-line tests that are available in emergency departments. Moreover, microbiological diagnosis is often difficult to achieve with common blood cultures, and further investigations require invasive procedures. The aim of this narrative review is to provide the most recent evidence-based recommendations on appropriate antinfective therapy in BJI in children. We conducted a review of recent literature by examining the MEDLINE (Medical Literature Analysis and Retrieval System Online) database using the search engines PubMed and Google Scholar. The keywords used were “osteomyelitis”, OR “bone infection”, OR “septic arthritis”, AND “p(a)ediatric” OR “children”. When BJI diagnosis is clinically suspected or radiologically confirmed, empiric antibiotic therapy should be started as soon as possible. The choice of empiric antimicrobial therapy is based on the most likely causative pathogens according to patient age, immunisation status, underlying disease, and other clinical and epidemiological considerations, including the local prevalence of virulent pathogens, antibiotic bioavailability and bone penetration. Empiric antibiotic treatment consists of a short intravenous cycle based on anti-staphylococcal penicillin or a cephalosporin in children aged over 3 months with the addition of gentamicin in infants aged under 3 months. An oral regimen may be an option depending on the bioavailability of antibiotic chosen and clinical and laboratory data. Strict clinical and laboratory follow-up should be scheduled for the following 3–5 weeks. Further studies on the optimal therapeutic approach are needed in order to understand the best first-line regimen, the utility of biomarkers for the definition of therapy duration and treatment of complications.

Microbial Modulation of Coagulation Disorders in Venous Thromboembolism

Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), is the third leading cause of cardiovascular death in the world. Important risk factors of thrombosis include bed restraint, surgery, major trauma, long journeys, inflammation, pregnancy, and oral contraceptives, previous venous thromboembolism, cancer, and bacterial infections. Sepsis increases the risk of blood clot formation 2–20 times. In this review, we discussed various mechanisms related to the role of bacteria in venous thrombosis also taking into consideration the role of the human microbiome. Many known bacteria, such as Helicobacter pylori, Chlamydia pneumoniae, Mycoplasma pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli, causing infections may increase the risk of thrombotic complications through platelet activation or may lead to an inflammatory reaction involving the fibrinolytic system. Additionally, the bacteria participate in the production of factors causing or increasing the risk of cardiovascular diseases. An example can be trimethylamine N-oxide (TMAO) but also uremic toxins (indoxyl sulfate), short-chain fatty acids (SCFA) phytoestrogens, and bile acids. Finally, we presented the involvement of many bacteria in the development of venous thromboembolism and other cardiovascular diseases.

Characteristics of Pyogenic Musculoskeletal Infections in Older Children and Adolescents

The characteristics and clinical consequences of pyogenic bone and joint infections in older children and adolescents have received little attention. This study evaluated the presentation and complications of musculoskeletal infections involving the pelvis and extremities in children older than 10 years. Thirty patients 10 to 17 years old (mean, 12.7 years old) were treated for musculoskeletal infections. Mean time to diagnosis was 9.2 days. Prior to correct diagnosis, 83% were assessed by at least 1 outpatient provider. At the time of admission, 55% were weight bearing and 93% were afebrile. Twenty-eight percent had a multifocal infection. More than one-third had serious medical complications or orthopedic sequelae; compared with patients without complications, this group had a significantly higher admission C-reactive protein and longer hospital stay. Symptoms of musculoskeletal infection common among young children may be absent in adolescents. Axial imaging is recommended to identify adjacent or multifocal disease. The Kocher criteria are less sensitive for septic hip arthritis in the adolescent population. Prompt recognition and treatment are critical to avoid medical and musculoskeletal complications. [Orthopedics. 2020;43(4):e291-e298.].

Bilateral subretinal abscess in community-acquired meticillin-susceptible Staphylococcus aureus infection

Subretinal abscesses due to endogenous staphylococcal blood stream infection is a rare occurrence. A young adult male presented with subretinal abscesses, necrotising pneumonia, pleural empyema, skin and soft tissue infection, muscle abscesses and deep vein thrombosis. Aspirate from one of the abscesses and blood culture revealed meticillin-susceptible Staphylococcus aureus. We present here a case of probable Panton-Valentine leucocidin (PVL) syndrome. PVL is a cytotoxin produced by S. aureus. Infection with PVL-positive S. aureus produces a clinical disease that is characterised by necrotising pneumonia and disseminated infection that often carries a high mortality. Our patient showed prompt clinical response to cloxacillin that was given for a total duration of 6 weeks. At the end of 6 weeks vision also recovered. The successful outcome in our patient was likely due to early and appropriate antibiotic therapy.

Management and outcomes of pediatric septic thrombophlebitis: a case series

Septic thrombophlebitis is a potentially life-threatening condition. Pediatric hematologists are often consulted to provide recommendations regarding anticoagulation management. We conducted a ten-year retrospective, single-center study of hospitalized pediatric patients who were treated for septic thrombophlebitis. Our primary outcome was resolution of thrombophlebitis. Twenty-eight patients were included in the study. Eighty-nine percent of patients received both antibiotic and anticoagulation therapy. The median durations of intravenous and total antibiotic therapy were 47.5 days (range 14-120) and 65 days (range 14-281), respectively, and median duration of anticoagulation therapy was 92 days (range 41-268). Resolution of thrombosis defined by magnetic resonance imaging, computed tomography, or ultrasound imaging was documented in 16 of 28 (57%) patients. Despite the high rate of persistent thrombosis, there was a low risk of relapse of infection in cases where antibiotic and/or anticoagulation was discontinued prior to complete resolution of the thrombus. Further research is needed to determine if duration of antibiotic and/or anticoagulation treatment can be shortened.

Staphylococcal species less frequently isolated from human clinical specimens - are they a threat for hospital patients?

Background

Coagulase-negative staphylococci belonging to S. haemolyticus, S. hominis subsp. hominis, S. simulans, and S. warneri are often described as etiological factors of infections. Staphylococci are a phylogenetically coherent group; nevertheless, there are differences among the species which may be important to clinicians.

Methods

We investigated selected virulence factors and antibiotic resistance that were phenotypically demonstrated, the presence and expression of genes encoding the virulence factors, and the type of the SCCmec cassette.

Results

The differences between the tested species were revealed. A great number of isolates produced a biofilm and many of them contained single icaADBC operon genes. Clear differences between species in the lipolytic activity spectrum could be related to their ability to cause various types of infections. Our studies also revealed the presence of genes encoding virulence factors homologous to S. aureus in the analysed species such as enterotoxin and pvl genes, which were also expressed in single isolates of S. simulans and S. warneri. S. haemolyticus and S. hominis subsp. hominis isolates were resistant to all clinically important antibiotics including ß-lactams. The identified SCCmec cassettes belonged to IV, V, VII, and IX type but most of the detected cassettes were non-typeable. Among the investigated species, S. hominis subsp. hominis isolates accumulated virulence genes typical for S. aureus in the most efficient way and were widely resistant to antibiotics.

Conclusions

Our results clearly indicated significant differences between the tested species, which might be a result of the horizontal gene transfer (HGT) and can lead to the formation and selection of multi-drug resistant strains as well as strains with new virulence features. Such strains can have a new clinical relevance.

Neonatal mortality and associated factors in the specialized neonatal care unit Asmara, Eritrea

BACKGROUND

Limited knowledge on the magnitude of neonatal mortality and associated factors is hampering early intervention in African countries.

OBJECTIVE

To determine neonatal mortality and associated factors in the Specialized Neonatal Care Unit Asmara, Eritrea.

METHODS

Medical records of all neonates admitted to the Specialized Neonatal Care Unit in 2016 were reviewed using a cross-sectional study. The most important causes of admission and mortality were analyzed. Univariate and multivariate logistic regression analysis was used to evaluate the strength of risk factors associated with neonatal mortality. Variables significant at P < 0.20 level in the univariate analysis were retained in the multivariate model. Model fit was evaluated using Hosmer and Lemeshow test (Chi-square = 12.89, df = 8; P = 0.116), implies the model's estimates fit the data at an acceptable level. Collinearity was assessed using variance inflation factor (VIF) < 4. P-value < 0.05 was considered statistically significant.

RESULTS

Of the 1204 (59.9% boys and 40.1% girls) neonates admitted in 2016, 79 (65.6/1000 live births) died. The major causes of admission were sepsis (35.5%), respiratory distress syndrome (15.4%) and perinatal asphyxia (10%). Major causes of death were respiratory distress syndrome (48.1%); extremely low birth weight (40.9%) and very low birth weight (30.5%). After adjustment, low birth weight (Adjusted odds ratio (AOR) = 4.55, 95% CI,1.97-10.50), very low birth weight (AOR = 19.24, 95% CI, 5.80-63.78), late admission (24 h after diagnosis) (AOR = 2.96, 95% CI, 1.34-6.52), apgar score (in 1 min AOR = 2.28, 95% CI, 1.09-4.76, in 5 min AOR = 2.07, 95% CI, 1.02-4.22), and congenital abnormalities (AOR = 3.95, 95% CI, 1.59-9.85) were significantly associated with neonatal mortality. Neonates that stayed > 24 h in the Specialized Neonatal Care Unit (AOR = 0.23, 95% CI, 0.11-0.46) had a lower likelihood of death. Overall 95.8% of mothers of neonates attended antenatal care and 96.6% were facility delivered. None of the maternal conditions were associated with neonatal mortality in this study.

CONCLUSIONS

Low birth weight, late admission, low apgar scores and congenital abnormalities were significantly associated with neonatal mortality in the Specialized Neonatal Care Unit. Early management of low birth weight, preterm births, and neonatal complications should be the priority issues for controlling local neonatal deaths.

Rare complications of Staphylococcus aureus infection in children: Case reports

Disseminated staphylococcal disease comprises a set of clinical manifestations secondary to multiple organ invasion that may range from cellulitis to sepsis. In pediatrics, the most common complications are osteoarticular and cutaneous infection; however, this article presents rare manifestations such as glomerulonephritis and thrombotic phenomena. This is the report of two cases of previously healthy adolescents: one presented with osteomyelitis and kidney injury, and the other, with lower limb cellulitis and respiratory deterioration with septic pulmonary embolism. The diagnostic process and additional management are described, highlighting the role of oxacillin in therapy. This article aims to highlight the importance of considering the rare manifestations of S. aureus infection, when the clinical evolution is abnormal, in order to initiate a timely treatment and get a better prognosis.

Psoitis and multiple venous thromboses caused by Panton Valentine Leukocidin-positive methicillin-sensitive Staphylococcus aureus in a 12-year-old girl: A case report

Panton Valentine Leukocidin (PVL) is one of the many toxins produced by Staphylococcus aureus. In Japan, PVL-positive S. aureus strains are mainly methicillin-resistant S. aureus (MRSA). Data regarding PVL-positive methicillin-sensitive S. aureus (MSSA) are scarce. In this report, we describe a case of severe infection by PVL-positive MSSA. A 12-year-old healthy girl was admitted with high fever and pain in the lower back. Computed tomography revealed a diagnosis of psoitis and multiple venous thromboses. Blood cultures obtained after admission revealed infection with MSSA. Her fever continued despite adequate antibiotic therapy. On the fifth hospitalization day, she developed bladder dysfunction, and an abscess was noted near the third lumbar vertebra. She underwent an emergency operation and recovered. Bacterial analyses revealed that the causative MSSA was a PVL-producing single variant of ST8 (related to USA300clone), of sequence type 2149. PVL is known to cause platelet activation. This case demonstrates the need for detailed analyses of the causative strain of bacteria in cases of S. aureus infection with deep vein thrombosis, even in cases of known MSSA infection.

A Clinical Prediction Algorithm to Stratify Pediatric Musculoskeletal Infection by Severity

OBJECTIVE

There are currently no algorithms for early stratification of pediatric musculoskeletal infection (MSKI) severity that are applicable to all types of tissue involvement. In this study, the authors sought to develop a clinical prediction algorithm that accurately stratifies infection severity based on clinical and laboratory data at presentation to the emergency department.

METHODS

An IRB-approved retrospective review was conducted to identify patients aged 0 to 18 who presented to the pediatric emergency department at a tertiary care children's hospital with concern for acute MSKI over a 5-year period (2008 to 2013). Qualifying records were reviewed to obtain clinical and laboratory data and to classify in-hospital outcomes using a 3-tiered severity stratification system. Ordinal regression was used to estimate risk for each outcome. Candidate predictors included age, temperature, respiratory rate, heart rate, C-reactive protein (CRP), and peripheral white blood cell count. We fit fully specified (all predictors) and reduced models (retaining predictors with a P-value ≤0.2). Discriminatory power of the models was assessed using the concordance (c)-index.

RESULTS

Of the 273 identified children, 191 (70%) met inclusion criteria. Median age was 5.8 years. Outcomes included 47 (25%) children with inflammation only, 41 (21%) with local infection, and 103 (54%) with disseminated infection. Both the full and reduced models accurately demonstrated excellent performance (full model c-index 0.83; 95% confidence interval, 0.79-0.88; reduced model 0.83; 95% confidence interval, 0.78-0.87). Model fit was also similar, indicating preference for the reduced model. Variables in this model included CRP, pulse, temperature, and an interaction term for pulse and temperature. The odds of a more severe outcome increased by 30% for every 10 U increase in CRP.

CONCLUSIONS

Clinical and laboratory data obtained in the emergency department may be used to accurately differentiate pediatric MSKI severity. The predictive algorithm in this study stratifies pediatric MSKI severity at presentation irrespective of tissue involvement and anatomic diagnosis. Prospective studies are needed to validate model performance and clinical utility.

LEVEL OF EVIDENCE

Level II-prognostic study.

Pediatric Musculoskeletal Infection: Hijacking the Acute-Phase Response

Tissue injury activates the acute-phase response mediated by the liver, which promotes coagulation, immunity, and tissue regeneration. To survive and disseminate, musculoskeletal pathogens express virulence factors that modulate and hijack this response. As the acute-phase reactants required by these pathogens are most abundant in damaged tissue, these infections are predisposed to occur in tissues following traumatic or surgical injury. Staphylococcus aureus expresses the virulence factors coagulase and von Willebrand binding protein to stimulate coagulation and to form a fibrin abscess that protects it from host immune-cell phagocytosis. After the staphylococcal abscess community reaches quorum, which is the colony density that enables cell-to-cell communication and coordinated gene expression, subsequent expression of staphylokinase stimulates activation of fibrinolysis, which ruptures the abscess wall and results in bacterial dissemination. Unlike Staphylococcus aureus, Streptococcus pyogenes expresses streptokinase and other virulence factors to activate fibrinolysis and to rapidly disseminate throughout the body, causing diseases such as necrotizing fasciitis. Understanding the virulence strategies of musculoskeletal pathogens will help to guide clinical diagnosis and decision-making through monitoring of acute-phase markers such as C-reactive protein, erythrocyte sedimentation rate, and fibrinogen.

Endovascular Thrombectomy of Septic Thrombophlebitis of the Inferior Vena Cava: Case Report and Review of the Literature

We describe the cases of 2 patients who had septic thrombophlebitis and were successfully managed with endovascular thrombectomy. Patient A developed septic thrombophlebitis of the inferior vena cava after several retroperitoneal resections for metastatic renal cell carcinoma. The thrombus was successfully removed via endovascular mechanical balloon thrombectomy. Patient B was a patient with pancreatic adenocarcinoma involving the portal vein who developed a septic inferior vena cava thrombus extending from the level and beyond the renal veins, for which she underwent endovascular thrombectomy. We argue that this approach is safe and feasible. It should be considered as a supplemental treatment modality for select decompensating patients who require lifesaving interventions and have contraindications to traditional management of surgical thrombectomy or excision of the involved venous segment.

Association of Vancomycin MIC and Molecular Characteristics with Clinical Outcomes in Methicillin-Susceptible Staphylococcus aureus Acute Hematogenous Osteoarticular Infections in Children

Strains of methicillin-resistant Staphylococcus aureus (MRSA), particularly those belonging to the USA300 pulsotype, have been well described to cause severe osteoarticular infections (OAIs). A vancomycin MIC of ≥1.5 μg/ml has been demonstrated to contribute to disease severity in adults with MRSA and even methicillin-susceptible S. aureus (MSSA) bacteremia. Little data exist describing the outcomes of MSSA OAIs in terms of molecular characteristics and vancomycin MIC. All patients/isolates were chosen from a surveillance study at Texas Children's Hospital (TCH). S. aureus OAI isolates were identified from 2011 to 2016 and subjected to vancomycin Etests, pulsed-field gel electrophoresis (PFGE), and PCR to determine Panton-Valentine leucocidin (PVL) production and agr group. Two hundred fifty-two cases of S. aureus OAI were identified; 183 cases were MSSA (72.6%). During the study period, a decrease in the proportion of cases secondary to MRSA was observed, declining from 37.8% to 15.9% (P = 0.02). Of the MSSA isolates, 26.2% and 23.5% were USA300 and PVL positive, respectively. An increase in the proportion of MSSA isolates with a vancomycin MIC of ≥1.5 μg/ml occurred in the study period (P = 0.004). In MSSA, an elevated vancomycin MIC was associated with multiple surgical procedures and venous thromboses, even when adjusting for empirical β-lactam use. An increase in vancomycin MIC was noted among isolates belonging to agr group 4 during the study period. Methicillin resistance is declining among S. aureus OAI isolates at TCH. Simultaneously, vancomycin Etest MICs are increasing among MSSA isolates. Vancomycin MICs of ≥2 μg/ml are associated with adverse clinical outcomes in MSSA irrespective of antibiotic choice, suggesting that this may be a surrogate for organism virulence.

Patient Factors Associated With Methicillin-Resistant Staphylococcus aureus Septic Arthritis in Children

Staphylococcus aureus is the most common causative organism in pediatric septic arthritis, with methicillin-resistant Staphylococcus aureus (MRSA) being responsible for a significant portion of these infections. Early identification and initiation of proper treatment may improve outcomes by minimizing potential morbidity. The purpose of this study was to identify variables obtained on initial patient presentation associated with MRSA septic arthritis. Sixteen factors were retrospectively evaluated in 109 consecutive pediatric patients diagnosed with culture-confirmed septic arthritis. Graphical and logistical regression analyses were employed to determine factors independently predictive of MRSA septic arthritis. Twenty-seven (25%) patients had MRSA and 82 (75%) had non-MRSA septic arthritis. C-reactive protein of 13.7 mg/L or greater, duration of symptoms of 4 days or more, heart rate of 126 beats per minute or greater, and absolute neutrophil count of 8.72×10³ cells/µL or greater were associated with MRSA septic arthritis. Ultimately, 98% of patients with 1 or no risk factors had non-MRSA and 96% of patients with MRSA septic arthritis had 2 or more positive risk factors. Elevated C-reactive protein, duration of symptoms, heart rate, and absolute neutrophil count are predictive of MRSA infection in the setting of pediatric septic arthritis and can be obtained on initial evaluation. In patients for whom there is concern for MRSA infection, this may guide more expedient treatment, such as early initiation of contact precautions and appropriate antibiotic therapy before culture results become available. [Orthopedics. 2018; 41(2):e277-e282.].

Analysis of Invasive Community-Acquired Methicillin-Susceptible Staphylococcus aureus Infections During a Period of Declining Community Acquired Methicillin-Resistant Staphylococcus aureus Infections at a Large Children's Hospital

BACKGROUND

The epidemiology of community acquired (CA) Staphylococcus aureus infections is changing in the United States. We investigated the current epidemiology of S. aureus infections at Texas Children's Hospital.

METHODS

Patients with CA-S. aureus skin and soft tissue and invasive infections were retrospectively identified from January 1, 2007 to December 31, 2014. Invasive CA-MSSA isolates were characterized by pulsed field gel electrophoresis, Spa typing, agr type and presence of lukSF-PV (pvl) genes. Medical records were reviewed. Statistical analyses included Fisher exact, χ for trend and Wilcoxon tests.

RESULTS

CA-MRSA infections decreased by 60.4% (1461-578 infections) from 2007 to 2014 (P < 0.0001), while CA-MSSA infections averaged 550 infections annually. Invasive CA-MRSA infections decreased by 67.2% from 61 to 20 infections (P < 0.0001); invasive CA-MSSA averaged 44 infections annually. Among 296 invasive CA-MSSA isolates, 74 (25%) isolates were USA300 and 88 (30%) were pvl+. USA300 declined among invasive CA-MSSA over time (P < 0.008). Musculoskeletal infections were most common (242/296, 82%); 52/242 (21.5%) isolates were USA300 and 62/242 (25.6%) pvl+. All 18 isolates from musculoskeletal infections with deep venous thrombosis and/or septic shock were pvl+ and 16/18 (88.9%) were USA300. Pneumonia isolates were mainly USA300 (8, 66.7%) and pvl+ (11, 91.7%).

CONCLUSIONS

MSSA now cause the majority of invasive CA-S. aureus infections at our institution. Molecular analysis of invasive CA-MSSA isolates suggests strain diversity with USA300 on the decline and that disease presentations are to some extent strain specific. Changes in the CA-S. aureus epidemiology may, in part, be related to changes in immunity to the USA300 clone in the general population.

Venous thromboembolism among pediatric orthopedic trauma patients: a database analysis

Using the 2012 Kids Inpatient Database, we assessed records of pediatric patients (<21 years old) with fractures of the upper limb, lower limb, spine, pelvis, and multiple locations and calculated the overall prevalence of venous thromboembolism (VTE) and associated potential risk factors. 387 (0.68%) of 57 183 patients with one or more fractures were diagnosed with VTE. Children sustaining fractures of the axial skeleton and those with multiple fractures had a higher prevalence of VTE than those with isolated extremity fractures. Associated risk factors included the presence of a central venous catheter. A prospective, multicenter study is needed to confirm our findings.

Pediatric Deep Venous Thrombosis Associated With Staphylococcal Infections: Single Institutional Experience

Deep venous thrombosis (DVT) has been previously reported in children with methicillin-resistant Staphylococcus aureus (MRSA). This study reviews our institutional experience by evaluating characteristics and outcomes of children with DVT and staphylococcal infections. Retrospective clinical data from 16 pediatric patients with DVT and staphylococcal infections over a 5-year period was obtained via medical record abstraction. Sixteen patients with a median age at diagnosis of 8 years were included. The most common infection encountered was osteomyelitis (56%). The most common isolated organism was MRSA (63%). Central venous catheters were present in 50% of cases. All patients received anticoagulation with low molecular weight heparin except 1 patient with superficial venous thrombosis who was managed conservatively. Fifty percent of patients had complete resolution of DVT by the end of treatment, 25% of the patients had early disappearance of the thrombus at 7 to 10 days. Only 2 patients (12.5%) had persistent thrombus at 6 months. Staphylococcal infections may increase the risk of DVT in children. Therefore, a high index of suspicion for DVT is warranted in children with Staphylococcal infections (particularly MRSA) to promptly diagnose, treat and minimize complications. Prophylactic anticoagulation in presence of staphylococcal infection, particularly MRSA, may be considered in future studies.

Panton-Valentine Leukocidin associated with S. aureus osteomyelitis activates platelets via neutrophil secretion products

Globalization and migration promote the spread of Panton-Valentine leukocidin (PVL)-positive Staphylococcus aureus strains. The toxin PVL is linked to the development of thrombosis in association with osteomyelitis. The mechanisms by which PVL drives thrombosis development are however still unknown. We demonstrate that PVL-damaged neutrophils activate platelets via neutrophil secretion products, such as α-defensins and the myeloperoxidase product HOCl, as well as the formation of HOCl-modified proteins. Neutrophil damage by PVL is blocked by anti-PVL-antibodies, explaining why especially young osteomyelitis patients with a low antibody titre against PVL suffer from thrombotic complications. Platelet activation in the presence of PVL-damaged neutrophils is prevented by α-defensin inhibitors and by glutathione and resveratrol, which are both inhibitors of HOCl-modified protein-induced platelet activation. Remarkably, intravenously infused glutathione also prevents activation of human platelets in an ex vivo assay. We here describe a new mechanism of PVL-neutrophil-platelet interactions, which might be extrapolated to other toxins that act on neutrophils. Our observations may make us think about new approaches to treat and/or prevent thrombotic complications in the course of infections with PVL-producing S. aureus strains.

Suppurative complications of acute hematogenous osteomyelitis in children

We carried out a case-control study in children with acute hematogenous osteomyelitis (AHO) with and without suppurative complications discharged from our institution over an 11-year period to test the hypothesis that abscess formation was associated with a delayed presentation to care. Of 102 children with AHO, 54 abscesses were documented in 46 patients (25 bone, 29 muscle). A delay in presentation was not associated with abscess formation (6.5 vs. 5.0 days, P=0.26). Overall, 78% of all bone abscesses were visible on initial MRI. Consistent use of MRI at presentation may identify children with suppurative complications of AHO.

The Influence of the Route of Antibiotic Administration, Methicillin Susceptibility, Vancomycin Duration and Serum Trough Concentration on Outcomes of Pediatric Staphylococcus aureus Bacteremic Osteoarticular Infection

BACKGROUND

Bacteremia is often one factor used in deciding the need for prolonged intravenous antimicrobial therapy in osteoarticular infections (OAIs). We examined treatment practices and outcomes of Staphylococcus aureus bacteremic osteoarticular infections (BOAIs) evaluated at Texas Children's Hospital.

METHODS

Cases of acute hematogenous OAI in children with positive blood cultures for S. aureus at Texas Children's Hospital between 2011 and 2014 were reviewed. Orthopedic complications included chronic osteomyelitis, growth arrest, pathologic fracture, avascular necrosis and chronic dislocation. Acute kidney injury was defined as a doubling of the baseline creatinine.

RESULTS

One hundred and ninety-two cases of S. aureus OAI were identified with 102 cases of BOAI included [35 methicillin-resistant S. aureus (MRSA)]. Twenty-five patients were discharged home on oral antibiotics. Patients discharged on oral antibiotics had a shorter duration of fever, had a more rapid decline in C-reactive protein and were less likely to have MRSA. The frequency of orthopedic complications did not increase in patients who received early transition to oral antibiotics. For patients with MRSA bacteremia, the rates of complications between those who received ≥7 days versus <7 days of vancomycin did not differ. Vancomycin serum troughs >15 µg/mL were not associated with a decreased duration of fever, bacteremia or hospitalization, need for repeat operation or orthopedic complications but were associated with acute kidney injury.

CONCLUSIONS

S. aureus BOAIs are associated with substantial morbidity. Early transition to oral therapy may be a safe option for select patients with S. aureus BOAI, including those due to MRSA. Prolonged courses of vancomycin and vancomycin troughs >15 μg/mL were not associated with improved outcomes for MRSA OAI.

Double-Edged Sword: Musculoskeletal Infection Provoked Acute Phase Response in Children

The acute phase response has a crucial role in mounting the body's response to tissue injury. Excessive activation of the acute phase response is responsible for many complications that occur in orthopedic patients. Given that infection may be considered continuous tissue injury that persistently activates the acute phase response, children with musculoskeletal infections are at markedly increased risk for serious complications. Future strategies that modulate the acute phase response have the potential to improve treatment and prevent complications associated with musculoskeletal infection.

The Contemporary Microbiology and Rates of Concomitant Osteomyelitis in Acute Septic Arthritis

BACKGROUND

Septic arthritis (SA) and acute osteomyelitis (AO) are among the most common serious bacterial infections of childhood. Knowledge of the microbiology of SA is critical to treatment. Awareness of the presence of attendant AO is also important to guide clinical management. We sought to describe the current microbiology of SA in children and clinical features associated with coexisting AO.

MATERIALS AND METHODS

Patients with SA were identified from the infectious diseases consult service records from 2010 to 2014. Patients with penetrating/open trauma and orthopedic hardware in situ were excluded.

RESULTS

A total of 168 patients with SA were included. The most common causative organism was Staphylococcus aureus accounting for 47.7% of cases (29.1% were methicillin-susceptible S. aureus and 18.5% were methicillin-resistant S. aureus), followed by group A streptococcus (GAS, 8.9%). The proportion of cases due to GAS increased from 2011 to 2014 (3.3%-16.7%; P = 0.1). One hundred eight (64.3%) patients had concurrent AO. The presence of osteomyelitis was associated with older median age (5.9 vs. 2.4 years; P = 0.04), a longer duration of symptoms (5 vs. 2.5 days; P < 0.001), S. aureus (62.1% vs. 21.7%; P < 0.001), bacteremia (46.2% vs. 20.3%; P = 0.001), a longer duration of fever after admission (5 vs. 2 days; P < 0.001) and a longer length of stay (10 vs. 6 days; P < 0.001).

CONCLUSIONS

Methicillin-resistant S. aureus continues to be an important cause of SA though GAS may be increasing in frequency. The presence of concomitant osteomyelitis is higher than previously reported and associated with older age, a longer duration of symptoms and fever, bacteremia and S. aureus.

Characterization of Community-Acquired Staphylococcus aureus Infections in Children

Background:

Limited data exist concerning characteristics of community-acquired Staphylococcus aureus infections (CA-SAI) in central and eastern Kentucky.

Objective:

To describe the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections from January 1, 2004 through December 31, 2005, compare the number of CA-MRSA infections between years, and contrast treatment interventions and antibiotic susceptibility patterns of CA-SAI.

Methods:

A concurrent and retrospective study was conducted in 125 patients less than 18 years of age with CA-SAI admitted to the hospital/clinic based on criteria from the Centers for Disease Control and Prevention. Data on demographics, length of stay, antibiotic therapy, and antibiotic susceptibilities were collected.

Results:

Seventy patients were included for analysis (CA-MRSA, n = 51; community-acquired methicillin-susceptible S. aureus [CA-MSSA], n = 19). No statistically significant differences were noted between the number of CA-MRSA infections and the total CA-SAI (9/15 in 2004 vs 42/55 in 2005; p = 0.15). Approximately 75% of patients with CA-SAI were admitted to the hospital with no significant difference in length of stay. Ninety percent of CA-SAI were skin and soft tissue infections. There was a significant difference between groups with cutaneous abscesses (CA-MRSA, n = 37 vs CA-MSSA, n = 6; p = 0.002). Greater than 95% of all isolates were susceptible to vancomycin and trimethoprim/sulfamethoxazole. Half of CA-MRSA patients received inappropriate antibiotic therapy with β-lactam antibiotics or clindamycin without confirmatory disk diffusion test. Twenty-five (49%) patients with CA-MRSA received surgical debridement (S/D) and/or incision and drainage (I/D) with concomitant antibiotic therapy. Four patients with CA-MRSA were rehospitalized for subsequent infections; all 4 received appropriate antibiotic therapy.

Conclusions:

A noticeable increase in CA-MRSA infections with cutaneous abscess between 2004 and 2005 was noted. In patients receiving inappropriate antibiotic therapy, treatment success was attributed to concomitant S/D and I/D. Further analysis should focus on the impact of antibiotic therapy alone or in combination with S/D and I/D on the incidence of subsequent CA-MRSA infections.

Osteoarticular Infections in Children

For a child with a suspected bone or joint infection, knowledge of the workup and initial therapy is important to provide quality care. Fever and pain are hallmarks of a pediatric osteoarticular infection, although occasionally the signs and symptoms can be more subtle. The use of C-reactive protein to diagnose and validate effective management of treatment has become standard. Multiple reports confirm the success of much shorter intravenous (IV) courses than traditionally taught. The ideal IV and oral antibiotic duration, as well as defining the markers indicating need for surgical intervention, are questions yet to be answered.

Musculoskeletal Sepsis Associated with Deep Vein Thrombosis in a Child

Deep vein thrombosis (DVT) is a rare disease in pediatric patients. We report a pediatric patient who developed DVT in association with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia complicated with septic arthritis, osteomyelitis, and myositis extensively. It is crucial to consider musculoskeletal infection associated with DVT in any child who presents with severe swollen limbs and limitations of motion. Prompt antibiotic and anticoagulant treatments should be initiated to reduce the risk of fatal complications.

Role of Operative or Interventional Radiology-Guided Cultures for Osteomyelitis

BACKGROUND AND OBJECTIVE

Acute hematogenous osteomyelitis (AHO) is a severe infection in children. Drainage of purulent collections in bones provides specimens for culture as well as therapeutic benefit. Interventional radiology (IR)-guided procedures may serve as a less invasive means of culture in select patients. We examined the impact of IR and surgically obtained cultures in the diagnosis and management of AHO.

METHODS

A retrospective review of cases of AHO was performed from 2011 to 2014. Patients with chronic disease, orthopedic hardware, puncture wounds, or an infected contiguous focus were excluded.

RESULTS

A total of 250 cases met inclusion criteria. Blood cultures were positive in 107 of 231 cases (46.3%), and 123 of 150 patients had positive cultures (82%) obtained by orthopedic surgery. Of these 123 patients, 62 (50.4%) had organisms identified only through operating room (OR) cultures. Of the 66 patients who had cultures obtained by IR, 34 (51.5%) had positive IR cultures. For those with positive IR cultures, 18 (52.9%) had negative blood cultures. Among the 80 patients with negative blood culture and positive OR/IR culture, the results changed antibiotic therapy in 68 (85%) patients.

CONCLUSIONS

IR or OR culture was the only means of identifying a pathogen in 80 of 216 cases (37%), and in >80% changed medical management. IR can be used effectively to obtain bone cultures in children with AHO not requiring open surgical drainage. Further research is needed to better understand the optimal utilization of IR and OR culture in pediatric AHO.

Clinical variables and Staphylococcus aureus virulence factors associated with venous thromboembolism in children

OBJECTIVES

Children with Staphylococcus aureus (SA) bacteremia risk developing venous thromboembolism (VTE). We sought to identify clinical variables and bacterial virulence factors associated with VTE in SA bacteremia.

STUDY DESIGN

This is a single-institution retrospective study of 229 children with SA bacteremia hospitalized from 2005 to 2008. Clinical data were abstracted from patient charts. Two-hundred three SA isolates were analyzed by polymerase chain reaction. The Pediatric Health Information System (PHIS) database was queried to identify subjects with a central venous line (CVL) or complex chronic conditions (CCC). Logistic regression analysis was employed to determine which factors most greatly influenced VTE.

RESULTS

VTE was present in 9.2% (n=21/229). Superficial thrombi were excluded. Mortality was greater in patients with VTE [24% vs. 6% (p=0.016)]. Among SA isolates available for virulence testing, the majority (70%; n=139) were methicillin-sensitive SA (MSSA). Methicillin-resistant SA (MRSA) infection was associated with VTE (p=0.01). The most common sites of thrombosis were extremity deep vein (58%; n=14/24), head/neck (29%; n=7), and visceral (13%; n=3). One subject had a pulmonary embolism. The presence of a CVL or a CCC was not associated with VTE. Independent predictors of VTE were C-reactive protein (CRP)≥20mg/dl [OR 4.2, 95% CI 1.16-15.25] and hemoglobin nadir ≤9g/dl [OR 5.2, 95% CI 1.3-20.64].

CONCLUSIONS

In addition to MRSA infection, CRP≥20mg/dl and hemoglobin nadir ≤9g/dl were associated with VTE in SA bacteremia. These factors may serve as markers for increased risk of VTE with invasive SA disease.

Inferior vena cava (IVC) filters in children: A 10-year single center experience

BACKGROUND

Venous thromboembolism (VTE) is an increasingly recognized problem among children and adolescents. Although inferior vena cava (IVC) filter placement for pulmonary embolism prevention is well reported in adults, data regarding safety and efficacy in the pediatric age group are lacking.

PROCEDURE

At a large university hospital with a level I trauma center, medical records of children and adolescents who underwent IVC filter insertion were reviewed. Appropriateness of referral for retrieval was assessed in each case.

RESULTS

Fifty-nine children and adolescents (mean age 16 years) successfully underwent IVC filter insertion. All filters placed were retrievable. In 47 patients (79.7%), prophylactic filters were placed in the absence of acute VTE in the setting of trauma. In eight patients (13.5%), filters were placed due to contraindication to anticoagulation therapy with concomitant lower extremity deep vein thrombosis or pulmonary embolism. Filters were successfully retrieved in only 12 patients (20.3%), although an attempt at removal was appropriate and feasible in over 90% of cases. Mean duration of follow-up was 2.1 (range 0.4-7.3) years. A significantly higher retrieval rate was found in patients followed at our thrombosis clinic (P < 0.01). Ten patients (17%) experienced at least one filter-related complication.

CONCLUSIONS

Although in most cases, IVC filters were placed for prophylactic indications, the evidence to support their role in this setting is limited. Their low retrieval rate and high filter-related complication rate question their extensive utilization in children. Dedicated follow-up is necessary to detect complications and to ensure that an attempt at retrieval is made when feasible.