Increasing Incidence of Streptococcus anginosus Group Intracranial Infections Associated With Sinusitis, Otitis Media, and Mastoiditis in Children.

BACKGROUND: The Streptococcus anginosus group (SAG) pathogens have the potential to cause head and neck space infections, including intracranial abscesses. Several centers noted an increase in intracranial abscesses in children during the SARS-CoV-2 pandemic, prompting a Centers for Disease Control and Prevention health alert in May 2022. We examined the epidemiology of pediatric intracranial abscesses at a tertiary care center with a focus on SAG pre- and post-pandemic. METHODS: Cases of intracranial abscesses of any microbiologic etiology admitted from January 2011 to December 2022 were identified using International Classification of Diseases 10 codes. Subjects were cross-referenced with culture results from the microbiology laboratory at Texas Children's Hospital. Cases included were those associated with either otitis media, mastoiditis or sinusitis and medical records were reviewed. RESULTS: A total of 157 cases were identified and 59.9% (n = 94) were caused by SAG. The incidence of all sinogenic/otogenic intracranial infections (P = 0.002), and SAG-specific infections (P = 0.004), increased from 2011 to 2022. SAG infection was more often associated with multiple surgeries, and these subjects were more likely to require craniotomy or craniectomy. Among sinogenic abscesses, S. intermedius was the most common pathogen, while among otogenic cases, S. pyogenes predominated. From March 2020 to Dec 2022, 9/49 cases tested positive for SARS-CoV-2 (18.4%); characteristics of infection were not significantly different among cases with and without SARS-CoV-2. CONCLUSIONS: Over the last decade, intracranial complications of sinusitis/otitis have been increasing, specifically those caused by SAG; this trend, however, predated the SARS-CoV-2 pandemic. SAG was associated with a greater need for surgical intervention, specifically neurosurgery. Further work is necessary to determine the cause for these rising infections.

Acute Hematogenous Osteomyelitis of the Pelvis in Children.

BACKGROUND: Pelvic involvement has been reported in 3%-14% of acute hematogenous osteomyelitis (AHO) cases in children. One guideline suggests need for a longer antibiotic course in pelvic AHO, however, recent data are lacking. We describe the clinical course of children with pelvic AHO and compare it to nonpelvic AHO. METHODS: A retrospective review of patients with a diagnosis of AHO admitted to Texas Children's Hospital from January 2012 to December 2020 was conducted. Patients 6 months-<19 years old and with ≤14 days of symptoms at admission were eligible. Patients with sickle cell disease or immunocompromised were excluded. Wilcoxon rank-sum test assessed for differences between continuous variables and Fisher exact for categorical variables using STATA 17. RESULTS: We compared 104 cases of pelvic AHO to 314 cases of nonpelvic AHO. Patients had similar microbiology, length of stay and length of antibiotic therapy. Patients with pelvic AHO had pyomyositis identified by magnetic resonance imaging more often (28.8 vs. 9.4%, P < 0.001) and bone abscess less often (22.1 vs. 46.5%, P < 0.001). Rates of chronic complications were comparable between patients with pelvic AHO and nonpelvic AHO (8.4% vs. 15.1%, P = 0.1). Nineteen patients (18.3%) with pelvic AHO received ≤30 antibiotic days without complications, but they had less need for intensive care or bone abscesses than patients treated longer. CONCLUSIONS: Pelvic AHO in children may be more frequent than previously reported but is not associated with more complications. Four weeks of therapy may be sufficient in selected patients. Prospective studies to compare outcomes with different lengths of therapy are needed.

Invasive Group A Streptococcus in Infants Less Than 1-year of Age From 2012 to 2022: A Single-Center Experience.

The incidence of invasive Group A Streptococcus (iGAS) has varied throughout the COVID-19 pandemic. We reviewed iGAS infections in infants ≤1 year from 2012 to 2022. Twenty-five percent of cases occurred in the last quarter of 2022. Pneumonia (21.8%) was the most common presentation. Twenty-one patients (65.6%) were successfully transitioned to oral antibiotics.

Assessing Risk for Complications in Acute Hematogenous Osteomyelitis in Children: Validation of 2 Predictive Scores.

BACKGROUND: Acute hematogenous osteomyelitis (AHO) can be associated with severe complications which can be difficult to predict in the clinical setting. The previously published predictive acute complication score ("A-SCORE") and chronic complication score ("C-SCORE") show promise, however, further external validation is needed. METHODS: We performed a retrospective study of 418 children with AHO and analyzed the performance of A-SCORE (variables included bone abscess, fever after 48 h of starting antibiotics, suppurative arthritis, disseminated disease, and delayed source control) to predict risk for acute complicated course (treatment failure, prolonged admission, and/or need for ≥2 bone debridements) and C-SCORE (includes disseminated disease, bone debridement, and CRP ≥10 mg/dL at 2-4 days after starting antibiotics) to predict chronic complications (growth restriction, pathologic fracture, chronic osteomyelitis, avascular necrosis, joint deformity, and/or frozen joint). RESULTS: An acute complicated course occurred in 106/418 (25.4%); 51/380 (13.5%) with complete follow-up data had a chronic complication. The A-SCORE performed with similar specificity (78%) and negative predictive value (NPV) (92%), and higher sensitivity (81%) and increased area under the receiver operating curve (AUC) (0.87) in our population. The C-SCORE performed with similar sensitivity (64%) and NPV (94%) but had lower specificity (86%) and AUC (0.71) than originally reported. Other variables associated with development of complications such as tibia involvement and bacteremia ≥2 days were identified but did not result in significantly improved predictive scores. CONCLUSIONS: Predictive A-SCORE and C-SCORE for AHO complications in children may help guide acute management and long-term follow-up decisions. Prospective studies are needed to determine their applicability.

Association of qacA/B and smr Carriage with Staphylococcus aureus Survival following Exposure to Antiseptics in an Ex Vivo Venous Catheter Disinfection Model.

Many health care centers have reported an association between Staphylococcus aureus isolates bearing efflux pump genes and an elevated MIC/minimal bactericidal concentration (MBC) to chlorhexidine gluconate (CHG) and other antiseptics. The significance of these organisms is uncertain, given that their MIC/MBC is typically far lower than the CHG concentration in most commercial preparations. We sought to evaluate the relationship between carriage of the efflux pump genes qacA/B and smr in S. aureus and the efficacy of CHG-based antisepsis in a venous catheter disinfection model. S. aureus isolates with and without smr and/or qacA/B were utilized. The CHG MICs were determined. Venous catheter hubs were inoculated and exposed to CHG, isopropanol, and CHG-isopropanol combinations. The microbiocidal effect was calculated as the percent reduction in CFU following exposure to the antiseptic relative to the control. The qacA/B- and smr-positive isolates had modest elevations in the CHG MIC90 compared to the qacA/B- and smr-negative isolates (0.125 mcg/ml vs. 0.06 mcg/ml, respectively). However, the CHG microbiocidal effect was significantly lower for qacA/B- and/or smr-positive strains than for susceptible isolates, even when the isolates were exposed to CHG concentrations up to 400 µg/mL (0.04%); this finding was most notable for isolates bearing both qacA/B and smr (89.3% versus 99.9% for the qacA/B- and smr-negative isolates; P = 0.04). Reductions in the median microbiocidal effect were also observed when these qacA/B- and smr-positive isolates were exposed to a solution of 400 µg/mL (0.04%) CHG and 70% isopropanol (89.5% versus 100% for the qacA/B- and smr-negative isolates; P = 0.002). qacA/B- and smr-positive S. aureus isolates have a survival advantage in the presence of CHG concentrations exceeding the MIC. These data suggest that traditional MIC/MBC testing may underestimate the ability of these organisms to resist the effects of CHG. IMPORTANCE Antiseptic agents, including chlorhexidine gluconate (CHG), are commonly utilized in the health care environment to reduce rates of health care-associated infections. A number of efflux pump genes, including smr and qacA/B, have been reported in Staphylococcus aureus isolates that are associated with higher MICs and minimum bactericidal concentrations (MBCs) to CHG. Several health care centers have reported an increase in the prevalence of these S. aureus strains following an escalation of CHG use in the hospital environment. The clinical significance of these organisms, however, is uncertain, given that the CHG MIC/MBC is far below the concentration in commercial preparations. We present the results of a novel surface disinfection assay utilizing venous catheter hubs. We found that qacA/B-positive and smr-positive S. aureus isolates resist killing by CHG at concentrations far exceeding the MIC/MBC in our model. These findings highlight that traditional MIC/MBC testing is insufficient to evaluate susceptibility to antimicrobials acting on medical devices.

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.

Going Back in Time: Increasing Penicillin Susceptibility among Methicillin-Susceptible Staphylococcus aureus Osteoarticular Infections in Children.

In the late 1940s to 1950s, Staphylococcus aureus isolates first-gained resistance to penicillin. Recently, some centers have described an increase in the proportion of methicillin susceptible S. aureus (MSSA) which are also susceptible to penicillin (PSSA). There are little data on the frequency of PSSA infections in children. We investigated the prevalence of penicillin susceptibility among pediatric MSSA acute hematogenous osteoarticular infection (OAI) isolates. MSSA OAI isolates were obtained through surveillance studies at Texas Children's and St. Louis Children's Hospitals from January 2011 to December 2019. All isolates underwent PCR for blaZ ß-lactamase, PVL genes and agr group. All blaZ negative isolates then underwent penicillin MIC determination. blaZ negative isolates with penicillin MIC ≤ 0.125 µg/mL were considered PSSA. Multilocus sequence typing (MLST) was conducted on a subset of isolates. A total of 329 unique isolates were included in the study. The median patient age was 9.2 years (IQR:5.1 to 12.2). Overall, 6.7% of isolates were penicillin susceptible. No PSSA were detected prior to 2015 but increased yearly thereafter. By the final study year, 20.4% of isolates were PSSA (P = 0.001). PSSA were similar to penicillin-resistant MSSA (PR-MSSA) isolates in terms agr group and PVL carriage as well as clinical presentation and outcomes. PSSA were of distinct sequence types compared to PR-MSSA. PSSA appears to be increasing among OAI in U.S. children. Overall, PSSA isolates are associated with a similar clinical presentation as penicillin-resistant isolates. The potential for use of penicillin treatment in PSSA OAI warrants further study.

Reduced Ceftaroline Susceptibility among Invasive MRSA Infections in Children: a Clinical and Genomic Investigation.

Ceftaroline represents an attractive therapy option for methicillin-resistant Staphylococcus aureus (MRSA). Little data is available, however, regarding the frequency of reduced susceptibility (RS) to ceftaroline among pediatric MRSA infections. We screened invasive MRSA isolates at a tertiary children's hospital for ceftaroline RS. Ceftaroline RS occurred in 2.9% of isolates and only among health care associated infections. Ceftaroline RS isolates were more often clindamycin-resistant. Sequencing data indicated the predominance of the CC5 lineage among ceftaroline RS isolates.

Microbiology and Treatment Outcomes of Community-Acquired Hematogenous Osteoarticular Infections in Infants ≤12 Months of Age.

We investigated the microbiology, management, and orthopedic outcomes of osteoarticular infections in infants age ≤1 year at our institution. Among 87 patients, Staphylococcus aureus was the most common pathogen (44.8%), followed by group B Streptococcus. Twenty-nine patients (33%), with a median age of 9.2 months, were transitioned to oral antibiotic therapy after ≤14 days of parenteral therapy; orthopedic outcomes were similar to those with prolonged parenteral therapy.

Bannwarth Syndrome: A Rare Manifestation of Pediatric Lyme Neuroborreliosis.

Lymphocytic meningoradiculitis (Bannwarth syndrome) is a rare manifestation of Lyme neuroborreliosis in children. It is the most common clinical manifestation of early Lyme neuroborreliosis in adults in European countries where the disease is endemic but is rare in children. We report an imported case of Bannwarth syndrome in a pediatric patient and review the literature for other pediatric cases reported.

Rat Bite Fever: Variability in Clinical Presentation and Management in Children.

Rat bite fever is a systemic illness most commonly caused by Streptobacillus moniliformis that is classically characterized by fever, rash and migratory polyarthritis. Here, we highlight the highly variable clinical presentations of rat bite fever in children and the importance of maintaining a high degree of suspicion so appropriate treatment can be promptly initiated.

Molecular Epidemiology of Contemporary Invasive Haemophilus influenzae Isolates in Texas Children.

Although vaccination has reduced the incidence of Haemophilus influenzae type b, nontypeable H. influenzae and other encapsulated types remain a health threat. Little is known regarding the contemporary molecular epidemiology of these organisms. We conducted multilocus sequence typing on invasive H. influenzae during a period of increasing incidence.

The Contemporary Epidemiology, Microbiology and Management of Chronic Osteomyelitis in US Children.

BACKGROUND: While the majority of pediatric osteomyelitis cases are acute in nature, a significant subset present with prolonged symptoms often associated with substantial morbidity. Little data exist to guide clinicians in the management of these infections. We sought to describe the epidemiology, clinical features and management of chronic osteomyelitis (CO) in children. METHODS: We reviewed hospital admissions for CO from 2011 to 2018 at Texas Children's Hospital. Cases were included if symptoms lasted ≥28 days on presentation. Cases were classified as those associated with: (1) a contiguous focus of infection; (2) penetrating trauma; (3) orthopedic hardware; (4) postacute CO (PACO, those occurring after ≥28 days of therapy for acute osteomyelitis); and (5) primary hematogenous CO. RESULTS: One hundred fourteen cases met inclusion criteria. The median patient age was 11.8 years and 35.9% had comorbidities. 70.2% of patients underwent ≥1 surgical procedure. A microbiologic etiology was identified in 72.8% of cases and Staphylococcus aureus was most common (39.4%). Contiguous focus of infection was more often associated with polymicrobial disease with or without Pseudomonas. Postacute CO was caused by S. aureus in 95%. The median duration of total therapy was 210 days. 26.3% of patients experienced treatment failure of which 46% underwent repeat hospital admission/surgery. There was no association between duration of intravenous therapy for CO and treatment failure. CONCLUSIONS: Children with CO represent a diverse group both in terms of pathogenesis and microbiology. Pathogenesis and clinical presentation can provide clues to microbiologic etiology. Prolonged intravenous therapy does not appear to improve outcomes in CO.

Follow-up Blood Cultures in Children With Staphylococcus aureus Bacteremia.

BACKGROUND: Staphylococcus aureus is a common pathogen seen in pediatric bloodstream infections. Currently, no evidence-based recommendations are used to guide decisions on the number of follow-up blood cultures (FUBCs) needed to demonstrate infection clearance. Unnecessary cultures increase the risk of false-positives, add to health care costs, and create additional trauma to children and their families. In this study, we examined risk factors for persistent S aureus bacteremia (SAB) and intermittent positive blood cultures (positive cultures obtained after a documented negative FUBC result) to determine the number of FUBCs needed to demonstrate infection clearance in children. METHODS: Patients ≤18 years who were hospitalized with SAB at Texas Children's Hospital in 2018 were reviewed. We assessed the impact of an infectious disease diagnosis (central line-associated bloodstream infection, osteomyelitis, soft tissue infection, endocarditis, etc) and medical comorbidities on bacteremia duration. Patients with intermittent positive blood cultures were studied to determine the characteristics of this group and overall frequency of reversion to positive cultures. RESULTS: A total of 122 subjects met the inclusion criteria. The median duration of bacteremia was 1 day (interquartile range: 1-2 days). Only 19 patients (16%) had bacteremia lasting ≥3 days, all of whom had a diagnosis of central line-associated bloodstream infection, osteomyelitis, or endocarditis. Intermittent positive cultures occurred in 5% of patients, with positive cultures after 2 negative FUBC results seen in <1% of patients. Intermittent positive cultures were strongly associated with osteomyelitis and endocarditis. CONCLUSIONS: On the basis of our sample of children with SAB, additional blood cultures to document sterility are not necessary after 2 FUBC results are negative in well-appearing patients.

Cefazolin Inoculum Effect and Methicillin-Susceptible Staphylococcus aureus Osteoarticular Infections in Children.

Select methicillin-susceptible Staphylococcus aureus (MSSA) strains may produce ß-lactamases with affinity for first-generation cephalosporins (1GCs). In the setting of a high inoculum, these ß-lactamases may promote the cleavage of 1GCs, a phenomenon known as the cefazolin inoculum effect (CzIE). We evaluated the prevalence and impact of CzIE on clinical outcomes among MSSA acute hematogenous osteomyelitis (AHO) cases. MSSA AHO isolates obtained from two children's hospitals between January 2011 and December 2018 were procured through ongoing surveillance studies. Isolates were tested for CzIE via a broth macrodilution assay using an inoculum of 107 CFU/ml; CzIE was defined as a cefazolin MIC of ≥16 µg/ml. Isolates were characterized by accessory gene regulator group (agr). The progression from acute to chronic osteomyelitis was considered an important outcome. A total of 250 cases with viable isolates were included. Notably, 14.4% of isolates exhibited CzIE with no observed temporal trend; and 4% and 76% of patients received a 1GC as an empirical and definitive therapy, respectively. CzIE isolates were more often resistant to clindamycin, belonged to agrIII, and associated with the development of chronic osteomyelitis. In multivariable analyses, agrIII, multiple surgical debridements, delayed source control, and CzIE were independently associated with progression to chronic osteomyelitis. A higher rate of chronic osteomyelitis was observed with CzIE isolates regardless of definitive antibiotic choice. CzIE is exhibited by 14.4% of MSSA AHO isolates in children. CzIE is independently associated with progression to chronic osteomyelitis in cases of AHO irrespective of final antibiotic choice. These data suggest that negative outcomes reported with CzIE may more accurately reflect strain-dependent virulence factors rather than true antibiotic failure.

Imaging of Paranasal Sinus Infections in Children: A Review.

Paranasal sinuses (PNS) infections are common in children. They may cause common and well-known complications, but also, unusual and potentially devastating complications. Diagnosing PNS infections and complications in children requires knowledge of the unique anatomy of the nasal cavity and the PNS. In fetal life, nasal mucosa evaginations into the lateral nasal walls initiate the development of the PNS. The PNS continue to develop after birth and complete their maturation and pneumatization at different ages during childhood which makes the pattern of PNS infections determined by patient age. Complications are caused by direct spread of the infection to the orbit, face, intracranial or osseous structures or hematogenous spread of the infection to the intracranial structures. Emergent imaging studies are often necessary in the evaluation of the complications in pediatric patients when the symptoms persist for 10 days and/or if there is evidence of intracranial or orbital complications. In addition, immunocompromised children are especially vulnerable to developing unusual complications. Computed tomography (CT) is excellent for determining whether there is intraorbital extension of PNS disease. However, when the infection approaches the orbital apex, a magnetic resonance imaging (MRI) study with contrast is necessary to assess spread into the cavernous sinus and the intracranial compartment. The goal of this manuscript is to review and characterize imaging findings of PNS infections using CT and MRI allowing determination of the extent of PNS infections and their common and unusual complications in children. In addition, a summary of the development of the normal PNS is provided.

Complications of Otitis Media and Sinusitis Caused by Streptococcus anginosus Group Organisms in Children.

BACKGROUND: The Streptococcus anginosus group (SAG, S. anginosus, S. intermedius and S. constellatus) are often associated with severe disease and abscess formation. In our institution, we observed an apparent increase in frequency of intraorbital and intracranial infections resulting from SAG at Texas Children's Hospital. We undertook a retrospective review to describe the frequency and clinical features of these infections. METHODS: We reviewed the database of the microbiology laboratory at Texas Children's Hospital from 2011 to 2018 for SAG-positive cultures. Cases included were those associated with (1) either otitis media or sinusitis and (2) Pott's puffy tumor, orbital abscesses, mastoiditis, epidural abscesses, subdural empyema, brain parenchymal abscesses or dural enhancement by imaging. The number of overall diagnoses were determined using diagnostic codes and used to estimate the proportion of disease caused by SAG. RESULTS: Ninety-five cases were identified meeting inclusion criteria. The median age of patients was 11.4 years, and 75.8% were previously healthy. S. intermedius was most commonly isolated (80%) followed by S. constellatus (12.6%) and S. anginosus (7.4%); 50.5% of cases were polymicrobial. Among polymicrobial cases, Staphylococcus aureus was most frequently isolated. All patients underwent surgical intervention. 8.4% of patients experienced persistent neurologic deficits. We observed a significant increase in disease incidence during the study period; in addition, the overall proportion of all intracranial infections caused by SAG increased. CONCLUSIONS: Complications of otitis media and sinusitis caused by SAG are associated with substantial morbidity. These infections are becoming increasingly common at our center although the precise reason for this temporal trend is unclear.

Microbiology of Osteoarticular Infections in Patients with Sickle Hemoglobinopathies at Texas Children's Hospital, 2000-2018.

The association between Salmonella spp. and osteoarticular infections in pediatric patients with major sickle hemoglobinopathies has been well established. However, the contemporary microbiology of these infections in such patients is unknown. We conducted a retrospective review of medical records at Texas Children's Hospital in Houston from 2000 to 2018 to investigate this question. Fifty cases were identified. In 23 (46%) cases, a pathogen was identified. Salmonella was the most common pathogen isolated, accounting for 61% of culture-positive cases followed by Staphylococcus aureus (21.7%).

Invasive Haemophilus influenzae Disease at Texas Children's Hospital, 2011 to 2018.

BACKGROUND: Universal vaccination with Haemophilus influenzae type b conjugate vaccines has significantly changed the epidemiology of invasive H. influenzae disease in the United States. We reviewed the epidemiology, clinical features, and outcomes in 61 patients with invasive H. influenzae disease evaluated at Texas Children's Hospital (TCH). METHODS: Cases of invasive H. influenzae disease, defined as isolation of the organism from cerebrospinal fluid, blood, synovial fluid or pleural fluid, during 2011 to 2018 among children cared for at TCH in Houston, TX, were included. RESULTS: We identified 61 cases of invasive H. influenzae disease in children ≤18 years of age. The overall hospitalization rate due to invasive H. influenzae disease increased between 2011 and 2018 (0 vs. 0.64/1000 hospitalizations; P = 0.019). The majority (80%) of infections occurred in children <5 years of age. Of the 61 H. influenzae infections, 24 (39.3%) infections were caused by nontypeable H. influenzae strains, 18 (29.5%) infections were caused by H. influenzae type a, 12 (19.7%) infections were caused by H. influenzae type f, 3 (4.9%) infections were caused by H. influenzae type e and 4 (6.6%) isolates were not typed. A total of 78.7% of the isolates were ß-lactamase negative. The most common clinical presentations were bacteremia without a source, pneumonia and meningitis. CONCLUSIONS: The hospitalization rate for H. influenzae invasive disease increased over an 8-year period at TCH. The overall trend was mainly driven by an increasing number of invasive infections caused by nontypeable H. influenzae and H. influenzae type a. Morbidity was substantial, especially in meningitis cases.

Clinical and Microbiologic Variables Predictive of Orthopedic Complications Following Staphylococcus aureus Acute Hematogenous Osteoarticular Infections in Children.

BACKGROUND: Staphylococcus aureus is the most common cause of acute hematogenous osteoarticular infections (AHOAIs) in children. The risk factors for the development of orthopedic complications (OC) after AHOAI are poorly understood. We sought to describe clinical and microbiologic variables present on the index admission that may predict OC in S. aureus AHOAI. METHODS: Staphylococcus aureus AHOAI cases were identified from 2011-2017 at Texas Children's Hospital and reviewed for the development of OC. OC included chronic osteomyelitis, growth arrest, avascular necrosis, chronic dislocation, and pathologic fracture. All S. aureus isolates were characterized by pulsed-field gel electrophoresis and agr group. RESULTS: A total of 286 cases were examined of which 27 patients (9.4%) developed OC. Patients who developed OC more often had infection with an agr group III organism (P = .04), bacteremia (P = .04), delayed source control (P < .001), ≥2 surgical procedures (P < .001), intensive care unit admission (P = .09), and fever >4 days after admission (P = .008). There was no association with OC and patient age, methicillin resistance, or choice/route of antibiotics. In multivariable analyses of OC, infection with agr group III S. aureus, prolonged fever, and delayed source control remained statistically significant. CONCLUSIONS: OC develop following S. aureus AHOAI in 9.4% of cases. Although the development of OC is likely multifactorial, agr group III organisms, prolonged fever, and delayed source control are independently associated with OC. Moreover, early aggressive surgical source control may be beneficial in children with S. aureus AHOAI.