Management of Pediatric Acute Hematogenous Osteomyelitis, Part II: A Focus on Methicillin-Resistant Staphylococcus aureus, Current and Emerging Therapies

Trimethoprim-Sulfamethoxazole for Pediatric Osteoarticular Infections

BACKGROUND

Trimethoprim-sulfamethoxazole (TMP-SMX) is active against most Staphylococcus aureus isolates but is not widely used for the treatment of pediatric osteoarticular infections.

METHODS

This was a comparative effectiveness study of hospitalized patients ≤18 years treated with TMP-SMX vs. other antibiotic regimens for acute osteoarticular infections between 2016 and 2021 at 3 hospitals using inverse probability of treatment weighted propensity score analysis. The primary outcome was treatment failure, a composite of unanticipated emergency department (ED) or outpatient visits, hospital readmissions, extension, or change of antibiotic therapy due to inadequate clinical response, or death, all within 6 months after completing antibiotics. The secondary outcome was antibiotic-associated adverse events (AEs) within 6 months. The exposed group for the treatment failure analysis included children who received ≥7 days of TMP-SMX and did not experience treatment failure while on another antibiotic. Children receiving at least 1 dose of TMP-SMX were the exposed group for the AE analysis.

RESULTS

One-hundred and sixteen patients met eligibility criteria; 26 (22.4%) patients were classified into the TMP-SMX cohort and 90 (77.6%) into the other antibiotics cohort (most commonly clindamycin, vancomycin, and cefazolin). There was no significant difference in treatment failure between TMP-SMX and other antibiotics (43% vs. 19%; 95% CI .9-10.4). More patients in the TMP-SMX cohort experienced an unplanned ED or outpatient visit (OR 4.8, 95% CI 1.3-17.8). There was no difference in hospital readmission, antibiotic change, or duration extension. Exposure to TMP-SMX was associated with more AEs (41% vs. 19%, P = .012).

CONCLUSIONS

Treatment with TMP-SMX was not associated with greater clinical failure but was associated with more AEs compared to alternative agents for the treatment of pediatric acute osteoarticular infections.

Early Transition to Oral Antimicrobial Therapy Among Children With Staphylococcus aureus Bacteremia and Acute Hematogenous Osteomyelitis

BACKGROUND

Staphylococcus aureus bacteremia (SAB) is a frequent complication of acute hematogenous osteomyelitis (AHO) in children, but data on the optimal duration of parenteral antibiotics prior to transition to oral antibiotics remains sparse. We examined clinical outcomes associated with early transition to oral antimicrobial therapy among children admitted to our institution with AHO and SAB, and evaluated the utility of a severity of illness score (SIS) to guide treatment decisions in this setting.

METHODS

Children with AHO and SAB admitted to our institution between January 1, 2009, and December 31, 2018, were retrospectively reviewed and stratified according to a previously validated SIS into mild (0-3), moderate (4-7) and severe (8-10) cohorts. Groups were assessed for differences in treatment (eg, parenteral and oral antibiotic durations, surgeries) and clinical response (eg, bacteremia duration, acute kidney injury, length of stay and treatment failure).

RESULTS

Among 246 children identified with AHO and SAB, median parenteral antibiotic duration differed significantly between mild (n = 80), moderate (n = 98) and severe (n = 68) cohorts (3.6 vs. 6.5 vs. 14.3 days; P ≤ 0.001). SIS cohorts also differed with regard to number of surgeries (0.4 vs. 1.0 vs. 2.1; P ≤ 0.001), duration of bacteremia (1.0 vs. 2.0 vs. 4.0 days; P ≤ 0.001), acute kidney injury (0.0% vs. 3.0% vs. 20.5%; P ≤ 0.001), hospital length of stay (4.8 vs. 7.4 vs. 16.4 days; P ≤ 0.001) and total duration of antibiotics (34.5 vs. 44.7 vs. 60.7 days; P ≤ 0.001). Early transition to oral antimicrobial therapy among mild or moderate SIS cohorts was not associated with treatment failure despite SAB.

CONCLUSIONS

SAB is associated with a wide range of illness among children with AHO, and classification of severity may be useful for guiding treatment decisions. Early transition to oral antimicrobial therapy appears safe in children with mild or moderate AHO despite the presence of SAB.

Italian consensus on the therapeutic management of uncomplicated acute hematogenous osteomyelitis in children

BACKGROUND

Acute hematogenous osteomyelitis (AHOM) is an insidious infection of the bone that more frequently affects young males. The etiology, mainly bacterial, is often related to the patient's age, but it is frequently missed, owing to the low sensitivity of microbiological cultures. Thus, the evaluation of inflammatory biomarkers and imaging usually guide the diagnosis and follow-up of the infection. The antibiotic treatment of uncomplicated AHOM, on the other hand, heavily relies upon the clinician experience, given the current lack of national guidelines for the management of this infection.

METHODS

A systematic review of the studies on the empirical treatment of uncomplicated AHOM in children published in English or Italian between January 1, 2009, and March 31, 2020, indexed on Pubmed or Embase search engines, was carried out. All guidelines and studies reporting on non-bacterial or complicated or post-traumatic osteomyelitis affecting newborns or children older than 18 years or with comorbidities were excluded from the review. All other works were included in this study.

RESULTS

Out of 4576 articles, 53 were included in the study. Data on different topics was gathered and outlined: bone penetration of antibiotics; choice of intravenous antibiotic therapy according to the isolated or suspected pathogen; choice of oral antibiotic therapy; length of treatment and switch to oral therapy; surgical treatment.

CONCLUSIONS

The therapeutic management of osteomyelitis is still object of controversy. This study reports the first Italian consensus on the management of uncomplicated AHOM in children of pediatric osteomyelitis, based on expert opinions and a vast literature review.

Epidemiology and Management of Acute Hematogenous Osteomyelitis, Neonatal Osteomyelitis and Spondylodiscitis in a Third Level Paediatric Center

Acute hematogenous osteomyelitis (AHOM) is a rare pathology in pediatric population. The aim of this study is to analyse the epidemiological data and the management, compared to European Society for Paediatric Infectious Disease (ESPID, European Society for Pediatric Infectious Diseases) guidelines 2017 of 216 children with AHOM, divided in three cohorts (neonatal-onset osteomyelitis, those with vertebral involvement and other types of osteomyelitis). We conducted a retrospective single center study, evaluating data from all the children (aged 0–18 years) consecutively admitted to the Meyer Children’s Hospital, during a period of ten years (1 January 2010–31 December 2019). Isolation of pathogen was possible in 65 patients and S. aureus was the most frequently involved (43/65 children). Magnetic Resonance Imaging (MRI, magnetic resonance imaging) was performed in 201/216 cases and was compatible with osteomyelitis in 185/201 of these children (92.03%). In the neonatal-onset osteomyelitis group the percentage of diagnostic ultrasound for osteomyelitis was 36.36% significantly higher than the other groups. The median duration of total antibiotic therapy was 37.5 days. In total, 186/199 children recovered without complications. The present study delineates three heterogeneous cohorts of patients. S. aureus is confirmed as the first pathogen for isolation in all three groups analysed. MRI represent a gold standard for diagnosis. Longer duration of antibiotics treatment was performed in neonatal and spondylodiscitis group, compared to the other types of osteomyelitis.

Acute osteoarticular infections in children are frequently forgotten multidiscipline emergencies: beyond the technical skills

Acute osteoarticular infections (AOI) should be treated as top emergencies. The first few days following the inception of infection are ultra-critical to long-term prognosis.A comprehensive road map for management of childhood AOI is still lacking despite recent advances in microbiology and imaging (magnetic resonance imaging). The many faces of childhood AOI warrant a multidiscipline approach to management.Laboratory and imaging findings of are still debatable and should not overshadow or delay a management plan based on the experienced physician's clinical judgment.Ample evidence-based practice supports the use of a few days of intravenous antibiotic administration followed by oral therapy until correlative clinical and basic laboratory (acute phase reactants) results improve.The growing body of evidence on 'high-risk' children/neonates of AOI warrants continual clinical extra-vigilance in identifying these patient subsets.Open drainage and debridement remain the mainstay of treatment of septic hips, whereas for other joints the use of alternative surgical techniques should be individualized or on case-by-case basis.Because the consequences of misdiagnosis of AOI are usually grave and permanent, proactive treatment/overtreatment is justified in the event of unconfirmed but suspicious diagnosis. Cite this article: EFORT Open Rev 2021;6:584-592. DOI: 10.1302/2058-5241.6.200155.

Antimicrobial prescribing for treatment of serious infections caused by Staphylococcus aureus and methicillin-resistant Staphylococcus aureus in pediatrics: an expert review

Introduction: Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA), remains a significant pathogen in children. Despite evidence of decreasing prevalence, MRSA bacteremia has been closely associated with complications, including certain infections (i.e. musculoskeletal and endovascular) linked to increased treatment failures.Areas covered: This expert review summarized recent published literature on the role of treatment, dosing and administration of antibiotics used to combat serious S. aureus infections in children. The pertinent antibiotics presented were vancomycin, oxazolidinones, semi-synthetic glycopeptides, daptomycin, tigecycline, novel cephalosporins, fosfomycin and lefamulin. Vancomycin has been the most commonly used antibiotic in empiric therapy for serious MRSA infection, with new key recommendations emphasizing a different approach to dosing and therapeutic monitoring. For other antibiotics, data remain limited or clinical trials are underway.Expert opinion: MRSA remains a significant pathogen in the pediatric population. As numerous therapeutic agents are available, many agents have limited data on usage in pediatric patients. Future studies require pharmacokinetic, safety and efficacy studies in pediatric patients to ensure appropriate therapeutic treatment and outcomes. Phage therapy has been used to treat deep-seated MRSA infections and is an emerging investigational treatment option.

The application of ceragenins to orthopedic surgery and medicine

Osteomyelitis and infections associated with orthopedic implants represent a significant burden of disease worldwide. Ceragenins (CSAs) are a relatively new class of small-molecule antimicrobials that target a broad range of Gram-positive and Gram-negative bacteria as well as fungi, viruses, and parasites. This review sets the context of the need for new antimicrobial strategies by cataloging the common pathogens associated with orthopedic infection and highlighting the increasing challenges of managing antibiotic-resistant bacterial strains. It then comparatively describes the antimicrobial properties of CSAs with a focus on the CSA-13 family. More recently developed members of this family such as CSA-90 and CSA-131 may have a particular advantage in an orthopedic setting as they possess secondary pro-osteogenic properties. In this context, we consider several new preclinical studies that demonstrate the utility of CSAs in orthopedic models. Emerging evidence suggests that CSAs are effective against antibiotic-resistant Staphylococcus aureus strains and can prevent the formation of biofilms. There remains considerable scope for developing CSA-based treatments, either as coatings for orthopedic implants or as local or systemic antibiotics to prevent bone infection.

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.

A dual PMMA/calcium sulfate carrier of vancomycin is more effective than PMMA-vancomycin at inhibiting Staphylococcus aureus growth in vitro

Both antibiotic-impregnated poly(methyl acrylate, methyl methacrylate) (PMMA) and antibiotic-impregnated calcium sulfate have been successfully used as local antibiotic delivery vehicles for the management of chronic osteomyelitis. Here, we examined the antibiotic elution characteristics and antibacterial properties of a composite drug delivery system consisting of PMMA/calcium sulfate carrying vancomycin (dual carrier-v) against Staphylococcus aureus, with PMMA loaded with vancomycin (PMMA-v) as a control. Vancomycin gradually degraded from dual carrier-v and PMMA-v up to about 8 and 6 weeks, respectively. At different elution time points, the inhibition zones of the dual carrier-v were larger than the inhibition zones of the PMMA-v (P < 0.05). The colony inhibition rate of the dual carrier-v was 95.57%, whereas it was 77.87% for PMMA-v. Scanning electron microscopy was used to demonstrate biofilm formation on the surface of plates treated with vancomycin-unloaded PMMA, whereas there was no biofilm formation on the surface of plates treated with dual carrier-v or PMMA-v. The dual carrier-v was more effective at antibacterial adhesion at each time point after immersion in simulated body fluid as compared with PMMA-v (P < 0.05). In conclusion, our results suggest that the dual carrier-v can release higher concentrations of antibiotics and inhibit bacteria growth more effectively in vitro as compared with PMMA-v. The dual carrier-v thus may have potential as an alternative strategy for osteomyelitis management.