Experience with linezolid therapy in children with osteoarticular infections

Management and Outcome of Invasive Clindamycin-Resistant MRSA Community-Associated Infections in Children

BACKGROUND

Clindamycin resistance among community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) complicates the management of a challenging infection. Little data exist to guide clinicians in the management of invasive clindamycin-resistant CA-MRSA infections in children and studies using oral regimens such as trimethoprim-sulfamethoxazole (TMP-SMX) and linezolid for treatment of these infections are limited. We sought to reevaluate antibiotic management among invasive CA-MRSA at a tertiary children's hospital.

METHODS

Cases of invasive clindamycin-resistant MRSA infections in children were identified through an ongoing S. aureus surveillance study. Eligible cases were those occurring in otherwise healthy children from 2011-2021. Medical records were reviewed.

RESULTS

Thirty-four subjects met inclusion criteria. The most common diagnoses were osteomyelitis (n = 17) and deep abscess (n = 7). The median duration of IV therapy was 11.5 days (IQR 6-42 days) and total therapy (IV + oral) was 32 days (IQR 23-42). Overall, 50% of patients were transitioned to oral therapy. Definitive antibiotics used for treatment included vancomycin (n = 15), TMP/SMX (n = 9), linezolid (n = 7), ceftaroline (n = 2), and doxycycline (n = 1). Cure rates were similar across definitive antibiotic therapies (vancomycin-73.3%; TMP/SMX-88.9%; ceftaroline 50%; linezolid and doxycycline-100%). Three subjects died of MRSA disease; two definitively treated with vancomycin and one with ceftaroline.

CONCLUSIONS

Vancomycin is the most commonly used agent in the treatment of invasive clindamycin-resistant CA-MRSA in children at our center. However, TMP/SMX and linezolid can be considered as oral options when completing treatment in select cases. Further work is needed to evaluate the optimal management of these infections.

Clinical Practice Guideline by the Pediatric Infectious Diseases Society (PIDS) and the Infectious Diseases Society of America (IDSA): 2023 Guideline on Diagnosis and Management of Acute Bacterial Arthritis in Pediatrics

This clinical practice guideline for the diagnosis and treatment of acute bacterial arthritis (ABA) in children was developed by a multidisciplinary panel representing the 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 ABA, including specialists in pediatric infectious diseases and orthopedics. The panel's recommendations for the diagnosis and treatment of ABA are based upon evidence derived from topic-specific systematic literature reviews. Summarized below are the recommendations for the diagnosis and treatment of ABA 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 approach (Grading of Recommendations Assessment, Development and Evaluation) (see Figure 1). 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.

Therapeutic Options and Outcomes for the Treatment of Children with Gram-Positive Bacteria with Resistances of Concern: A Systematic Review

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative Staphylococci (MR-CoNS), and vancomycin-resistant Enterococci (VRE) are increasing worldwide and represent a threat for the limited treatment options in pediatric patients and neonates compared to adults. Recommendations in pediatrics are mainly extrapolated from adults' studies.

METHODS

A literature search for the treatment of these pathogens in children (<18 years old) was conducted in Embase, MEDLINE, and Cochrane Library. Studies reporting data on single-patient-level outcomes related to a specific antibiotic treatment for multidrug resistant (MDR) Gram-positive bacterial infection in children were included. Studies reporting data from adults and children were included if single-pediatric-level information could be identified (PROSPERO registration: CRD42022383867).

RESULTS

The search identified 11,740 studies (since January 2000), of which 48 fulfilled both the inclusion and the exclusion criteria and were included in the analysis: 29 for MRSA, 20 for VRE, and seven for MR-CoNS. Most studies were retrospective studies. Vancomycin was mainly used as a comparator, while linezolid and daptomycin were the most studied antimicrobials showing good efficacy.

CONCLUSIONS

Linezolid showed a safety and efficacy profile in a neonatal setting; daptomycin is increasingly used for MRSA, but the evidence is scarce for VRE.

An Unusual Presentation of Community-Acquired Methicillin-Resistant Staphylococcus aureus Infection in a Child Treated With Linezolid

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a major public health concern. MRSA isolates are classified into community-acquired MRSA (CA-MRSA) and healthcare-associated MRSA based on their epidemiology, antibiotic susceptibility patterns, and molecular characteristics. CA-MRSA typically causes skin and soft tissue infections. However, the incidence of invasive infections has increased in recent years. This paper describes the case of a 12-year-old girl with an unusual presentation of CA-MRSA. The patient presented with right thigh pyomyositis complicated by deep vein thrombosis, septic pulmonary embolism, and necrotizing pneumonia. The MRSA isolate was susceptible to vancomycin but resistant to the other anti-MRSA antibiotics. The patient was successfully treated with linezolid after clinical deterioration with vancomycin. A literature review comparing vancomycin and linezolid in invasive MRSA infections among children indicated that linezolid has better lung and tissue penetration than vancomycin, and an early switch is warranted in the case of deterioration after vancomycin administration and the lack of other alternatives.

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.

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.

A systematic review and meta-analysis of myelosuppression in pediatric patients treated with linezolid for Gram-positive bacterial infections

BACKGROUND

The incidence of linezolid-induced myelosuppression in pediatric patients was reported at large difference among prospective studies, with a range of 0-24%. Additionally, there is little study which evaluated the impact of linezolid administration period on myelosuppression in pediatric patients, while it is one of the most frequent reason that linezolid therapy has to be discontinued in adult patients. Here, we performed a systematic review and meta-analysis to reveal the incidence of linezolid-induced thrombocytopenia and anemia, and impact of the administration period of linezolid on myelosuppression based on individual data analysis of pediatric patients.

METHODS

We systematically searched the Scopus, EMBASE, Cochrane Central Register of Controlled Trials, PubMed, and CINAHL until April 2020. We investigated the incidence of linezolid-induced thrombocytopenia and anemia using pooled analysis, and evaluated the impact of linezolid administration period on myelosuppression using meta-analysis.

RESULTS

Thirteen studies with 969 pediatric patients were identified. The pooled incidences of thrombocytopenia and anemia were 9% (95% confidence interval (CI), 3-18%) and 4% (95% CI, 0-12%), respectively. Our meta-analysis showed the extension of linezolid administration period (more than 14 days) resulted in higher incidence of thrombocytopenia (OR 4.86, 95% CI 1.10-21.55) and anemia (OR 4.57, 95% CI 0.13-160.49).

CONCLUSIONS

The incidence of linezolid-induced myelosuppression in pediatric patients was less than 10%. However, our meta-analysis revealed linezolid administration period for more than 14 days was one of risk factors associated with linezolid-induced myelosuppression. Therefore, especially for pediatric patients treated with linezolid for more than 14 days, careful monitoring of myelosuppression is required.

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.

Acute infectious osteomyelitis in children: new treatment strategies for an old enemy

BACKGROUND

Acute osteomyelitis still represents a significant clinical challenge, with an increasing incidence in paediatric population. A careful assessment and a rapid diagnosis with proper timing and choice of empirical antimicrobial therapy are necessary to avoid sequelae. The initial treatment should consist of empirical antibiotic therapy, to cover the major responsible pathogens in each age group.

DATA SOURCES

We made a literature search with PubMed and Cochrane database from 2000 to 2019 in English, French, and Spanish languages using the key words "osteomyelitis, children, clinical, diagnosis, and treatment".

RESULTS

The child's clinical features, age, and the microbiological profile of the geographic area should be evaluated for diagnosis and in the choice of antibiotic treatment. Latest data suggest the administration of intravenous antibiotics for a short period, with subsequent oral therapy, according to the improvement of clinical status and inflammatory markers. For children older than 3 months, the shift to oral medications is already possible after a short course of intravenous therapy, until recovery. The timing for the shift from cefazolin to cephalexin or cefuroxime, intravenous clindamycin to oral clindamycin, and intravenous ceftriaxone + oxacillin to oral equivalents will be decided according to the improvement of clinical status and inflammatory markers. We also present the approach to osteomyelitis due to difficult pathogens, such as Methicillin-resistant Staphylococcus aureus (MRSA) and Panton-Valentine leukocidin (PVL)-positive S. aureus infections.

CONCLUSION

In this review, we present the current approach to the clinical diagnosis and management of osteomyelitis in childhood, with an update on recent recommendations, as a useful instrument to understand the rationale of antibiotic therapy.

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

Methicillin-resistant Staphylococcus aureus (MRSA) has become the most prevalent cause of acute hematogenous osteomyelitis (AHO) in pediatric patients. This increase in MRSA is due to the rise in community-acquired MRSA. Therefore, it is important that clinicians are aware of the various and upcoming therapies that cover this bacterium. A literature search of the Medline database was performed from creation through January 2018. Articles chosen for the review emphasize well-established MRSA treatment options for pediatric AHO, newer therapies on the horizon, and important pharmacokinetics and pharmacodynamic concepts for treatment. Traditional therapies, including vancomycin and clindamycin, remain effective for the treatment of pediatric AHO. When these agents cannot be used, evidence in AHO has been growing for daptomycin, linezolid, and ceftaroline. Further initial pediatric data with the long-acting lipoglycopeptides show promise and in the future may provide a role in AHO treatment in children.

The Use of an "Internal Fixator Technique" to Stabilize Pathologic Fractures Developing Secondary to Osteomyelitis

BACKGROUND

There is no consensus on the materials and the techniques to use in fixing pathologic fractures secondary to osteomyelitis. This study reports the results of the fixation of pathologic fractures secondary to osteomyelitis using the "internal fixator technique."

METHODS

The internal fixator technique was performed on 11 children and adolescents with fractures secondary to osteomyelitis between 2003 and 2010. A retrospective chart review was conducted to record the following: age, sex, the anatomic region of infection, the time delay from symptom onset to fracture, the classification of chronic osteomyelitis, the Cierny-Mader classification, the causative organism, surgeries, the length of hospitalization, the location and the pattern of fracture, the duration of infection, the length of follow-up, and complications.

RESULTS

The patients included 7 male and 4 female patients with a mean age of 8.7 (range, 6 to 13) years. Pathologic fractures were as follows: 7 femur and 4 tibia. Nine of them were in the metaphysis and 2 others were located in the diaphysis. The time delay from symptom onset to fracture was 3.36 (1 to 9) months. The anatomic region of infection was the diaphysis in 2 cases and the metaphysis in 9 cases. Fractures patterns were short oblique and transverse. The length of hospitalization was a mean of 7 days. The duration of infection ranged from 1 to 12 (mean, 4.38) months. The mean duration of follow-up was 57.09 (range, 36 to 73) months from the initial presentation. Only 2 patients developed shortening, for which no additional intervention was performed.

CONCLUSIONS

This case series demonstrates that the "internal fixator technique" is an acceptable alternative to the management of pathologic fractures of the femur or the tibia in children and adolescents with unresolved acute and chronic osteomyelitis. Infections were resolved in all cases and fractures were sufficiently stabilized to allow union with a low complication rate.

LEVEL OF EVIDENCE

Level IV-therapeutic.

[Acute haematogenous osteomyelitis in children : Diagnostic algorithm and treatment strategies]

Acute haematogenous osteomyelitis (AHO) in children is a severe condition. A delay in diagnosis and insufficient treatment may result in deformities, chronicity and sepsis. Therefore a structured diagnostic workup has to be followed in order to diagnose or rule out osteomyelitis. To identify the causative agent for targeted antibiotic treatment, a bone biopsy or puncture should be performed. However, approximately 25% of cases are culture-negative even after biopsy. The knowledge of the typical age-dependent bacterial spectrum is essential for empirical antibiotic therapy. The principal causative organism is Staphylococcus aureus. Surgery is not routinely required in paediatric acute osteomyelitis but surgical intervention is indicated if an abscess is detected. Secondary septic arthritis is a serious complication which has to be treated immediately by surgical intervention. Nevertheless, complete regeneration can be expected in up to 80% of children with AHO.

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.

Optimizing therapy for vancomycin-resistant enterococcal bacteremia in children

PURPOSE OF REVIEW

Uncertainties exist regarding the optimal treatment for vancomycin-resistant enterococcal (VRE) bloodstream infections, particularly in settings in which ampicillin cannot be used.

RECENT FINDINGS

Quinupristin-dalfopristin, linezolid, and daptomycin, all approved between 1999 and 2003, represent the mainstays of therapy for VRE bacteremia, although only linezolid has been specifically approved by the United States Food and Drug Administration for this indication. The main objective of this review is to compare the relative efficacies, dosing strategies, and side-effect profiles of quinupristin-dalfopristin, linezolid, and daptomycin for VRE bacteremia in the pediatric population. A brief description of recently approved broad-spectrum Gram-positive agents that may have a role in the management of VRE bacteremia in upcoming years is also provided.

SUMMARY

Linezolid, despite its bacteriostatic activity against VRE, may be the most versatile of the available drugs. It has activity against both Enterococcus faecalis and E. faecium, can be administered orally, and resistance appears to be less of a concern with linezolid compared with the other agents. Additionally, the results of two recent meta-analyses demonstrate more favorable outcomes with linezolid compared with daptomycin for the treatment of VRE bacteremia. The clinical pharmacokinetics of linezolid have been well described in children. The most notable concern with linezolid, however, is toxicities associated with prolonged use. Until more prospective data are available, we favor linezolid as first-line therapy for the treatment of VRE bacteremia in children.

[SEIP-SERPE-SEOP Consensus document on the treatment of uncomplicated acute osteomyelitis and septic arthritis]

This is a Consensus Document of the Spanish Society of Paediatric Infectious Diseases (Sociedad Española de Infectología Pediatrica), Spanish Society of Paediatric Rheumatology (Sociedad Española de Reumatología Pediátrica) and the Spanish Society of Paediatric Orthopaedics (Sociedad Española de Ortopedia Pediátrica), on the treatment of uncomplicated acute osteomyelitis and septic arthritis. A review is presented on the medical and surgical treatment of acute osteoarticular infection, defined as a process with less than 14 days of symptomatology, uncomplicated and community-acquired. The different possible options are evaluated based on the best available scientific knowledge, and a number of evidence-based recommendations for clinical practice are provided.

Recent lessons for the management of bone and joint infections

The epidemiology and clinical manifestations of osteoarticular infections are changing primarily as a result of the emergence of community-acquired methicillin-resistant Staphylococcus aureus infections. Multifocal disease, venous thrombosis and pathologic fractures are manifestations of CA-MRSA osteomyelitis. MRI is the diagnostic imaging modality of choice for musculoskeletal infections. Nafcillin/oxacillin or cefazolin remains the antibiotic of choice for treating infections caused by MSSA. A β-lactam antibiotic is recommended for Kingella kingae. Vancomycin and clindamycin are the first line agents for treating osteomyelitis caused by CA-MRSA. A short course of parenteral antibiotics followed by appropriate oral antibiotics is equivalent to total course of parenteral antibiotics for most patients and avoids the risks associated with PICCs. Surgical drainage of subperiosteal abscesses and surrounding pyomyositis is common with S. aureus clones currently circulating. Collaboration with hematologists for managing patients with venous thromboses is recommended.

Bone and joint infections

An acute osteoarticular infection in a child is most often hematogenous. The infection manifests as osteomyelitis or septic arthritis. The most common causative organism is Staphylococcus aureus. Medical advice is usually sought within 2 to 6 days from the onset of symptoms. A child with an osteomyelitis in a lower extremity characteristically presents with limping with or without notable local tenderness, whereas acute septic arthritis is often readily visible because the joint is red, tender, and swollen. Early diagnosis and prompt treatment remain pivotal in avoiding complications in acute bacterial bone and joint infections.

[Acute osteomyelitis: epidemiology, clinical manifestations, diagnosis and treatment]

BACKGROUND AND AIMS

The present study focuses on the epidemiology, clinical and laboratory data, and management of osteomyelitis in a pediatric third level hospital.

METHODOLOGY

All cases of children under 15 years-old admitted with osteomyelitis between 2000 and 2011 were retrospectively reviewed until July 2006, then prospectively from then until 2011.

RESULTS

A total of 50 patients were identified (52% males) with median age at diagnosis of 2 years. Principal onset manifestations were pain (94%), functional impairment (90%) and fever (72%). The femur (32%), fibula (28%) and calcaneus (22%) were most affected bones. Leucocytosis > 12.000/μl was found in 56%, elevated ESR > 20 mm/h in 26%, and elevated CRP > 20 mg/L in 64%. Blood culture was positive in 20%, with group A streptococcus being the most frequently isolated bacteria (11%). All diagnoses were confirmed by a (99)Tc scintigraphy bone scan. Antibiotic therapy was initially intravenously (mean time of administration: 10 days ± 3 SD), followed by oral medication (mean time of administration: 18 days ± 6 SD). Surgery was necessary in 3 patients. Evolution of all cases was excellent, despite 3 exceptions that resolved over time.

CONCLUSIONS

The current short-term intravenous therapy led to shorter hospitalizations. There were no statistically significant differences between time from clinical onset or in CRP levels at discharge compared to long-term therapies prior to 2006.

Safety and efficacy of linezolid in 16 infants and children in Japan

Linezolid, an oxazolidinone antibiotic, exhibits a broad spectrum of activity against Gram-positive bacteria. It has been licensed for adult use in Japan since 2006 for MRSA infections, and has also been used off-label for pediatric patients. At our university hospital, a total of 16 infants and children (including one non-Japanese Asian) were administered linezolid owing to infection with multidrug-resistant Gram-positive bacteria, after consent had been provided. All patients had severe underlying diseases or indications for surgery. Eighty-eight percent of the causal microorganisms were methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-resistant coagulase-negative Staphylococcus and all were sensitive to linezolid. Linezolid was administered because the antecedent anti-MRSA medications were ineffective or contraindicated, or intravenous-to-oral switch therapy was requested owing to cardiac or orthopedic surgical-site infections. The median duration of administration was 13 days (range 3-31 days). The overall efficacy was 91 % (10/11) in those for whom efficacy could be evaluated. Only two patients (both teen-aged) encountered linezolid-related adverse effects (13 %, 2/16). One patient showed elevation of liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), requiring that administration be withdrawn, but enzyme levels returned to normal after the patient had been switched to vancomycin. The other patient showed transiently decreased platelet counts. Linezolid is considered generally safe and effective for children in Japan, especially for those who cannot use other anti-MRSA medications or those who require oral antibiotics for infections with multidrug-resistant Gram-positive bacteria.

Clinical experience with linezolid in infants and children

The worldwide spread of multidrug-resistant organisms has required the development of new antimicrobials. Linezolid, the first oxazolidinone, has a broad spectrum of activity against Gram-positive bacteria, including resistant strains. Although approved by the Food and Drug Administration in 2002, the clinical experience with linezolid in the paediatric population is still limited, also given the fact that in most European countries the paediatric use of linezolid is off-label. In this paper we summarize the actual evidence on both licensed and off-label clinical uses of linezolid in children, including efficacy, safety and tolerability issues. Taking into account the potential bias in comparing heterogeneous clinical trials and reports, the available literature data suggest that linezolid is a safe and effective agent for the treatment of serious Gram-positive bacterial infections in neonates and children. At present, linezolid is reserved for those children who are intolerant to or fail conventional agents. A linezolid-containing regimen can be a valuable option for treating multidrug-resistant and extensively drug-resistant tuberculosis in children as well as disseminated non-tuberculous mycobacterial infections. Given the rare occurrence of serious side effects, careful monitoring of haematological parameters, possible drug interactions and neurological manifestations is recommended in linezolid-treated children, especially in case of prolonged treatments. Appropriate linezolid dosage and hospital infection control measures are essential to avoid the spread of linezolid resistance. Further studies are needed to establish novel paediatric indications for linezolid use and to assess the tolerability of long-term treatments.

Antibiotic treatment for acute haematogenous osteomyelitis of childhood: moving towards shorter courses and oral administration

Acute haematogenous osteomyelitis (AHOM) of childhood usually affects the long bones of the lower limbs. Although almost any agent may cause AHOM, Staphylococcus aureus is the most common bacterium, followed by Streptococcus pneumoniae and, in some countries, Salmonella spp. and Kingella kingae. Magnetic resonance imaging (MRI) has improved the diagnostic accuracy of traditional radiography and scintigraphy. Except for the pre-treatment diagnostic sample from bone before the institution of antibiotic therapy, no other surgery is usually required. Traditionally, non-neonatal AHOM has been treated with a 1-3-month course of antibiotics, including an intravenous (i.v.) phase for the first weeks, but recent prospective randomised studies challenge this approach. For most uncomplicated cases, a course of 20 days including an i.v. period of 2-4 days suffices, provided large enough doses of a well-absorbed agent (clindamycin or a first-generation cephalosporin, local resistance permitting) are used, administration is four times daily and most symptoms and signs subside within a few days. Serum C-reactive protein (CRP) is a good guide in monitoring the course of illness, and the antimicrobial can usually be discontinued if CRP has decreased to <20 mg/L. Newer and costly agents, such as linezolid, should be reserved for cases due to resistant S. aureus strains. AHOM in neonates and immunocompromised patients probably requires a different approach. Because sequelae may develop slowly, follow-up for at least 1 year post hospitalisation is recommended.

Clinical practice guidelines by the infectious diseases society of america for the treatment of methicillin-resistant Staphylococcus aureus infections in adults and children

Evidence-based guidelines for the management of patients with methicillin-resistant Staphylococcus aureus (MRSA) infections were prepared by an Expert Panel of the Infectious Diseases Society of America (IDSA). The guidelines are intended for use by health care providers who care for adult and pediatric patients with MRSA infections. The guidelines discuss the management of a variety of clinical syndromes associated with MRSA disease, including skin and soft tissue infections (SSTI), bacteremia and endocarditis, pneumonia, bone and joint infections, and central nervous system (CNS) infections. Recommendations are provided regarding vancomycin dosing and monitoring, management of infections due to MRSA strains with reduced susceptibility to vancomycin, and vancomycin treatment failures.

Factors associated with nasal colonization of methicillin-resistant Staphylococcus aureus among healthy children in Taiwan

Methicillin-resistant Staphylococcus aureus (MRSA) has been identified as a major cause of community-associated (CA) S. aureus infections in the past decade. The main reservoir in the community for MRSA and the factors contributing to its worldwide spread remain poorly defined. Between July 2005 and June 2008, a total of 6,057 healthy children 2 to 60 months of age were screened for carriage of S. aureus and Streptococcus pneumoniae in Taiwan. The prevalence and epidemiological factors influencing MRSA carriage were determined. MRSA strains were tested for antimicrobial susceptibility and underwent molecular characterization. The overall prevalences of MRSA and S. aureus carriage were 7.8% and 23.2%, respectively. A majority (88%) of MRSA isolates belonged to a common Asian-Pacific CA-MRSA lineage, multilocus sequence type 59, and were resistant to multiple non-beta-lactam antibiotics. The carriage rate of MRSA was higher among subjects 2 to 6 months old (P < 0.0001), residing in northern Taiwan (P = 0.0003), and enrolled later in the study (P < 0.0001). MRSA colonization was associated with the number of children in the family (adjusted odds ratio [aOR], 1.114; 95% confidence interval [CI], 1.002 to 1.240; P = 0.0463) and day care attendance (aOR, 1.530; 95% CI, 1.201 to 1.949; P = 0.0006). Breast feeding (P < 0.0001) and colonization with S. pneumoniae (P = 0.0170) were protective against MRSA colonization. We concluded that epidemic CA-MRSA strains increasingly colonized Taiwanese children between 2005 and 2008. The carriage rate varied significantly across different demographical features. Crowding was an independent environmental risk factor that might accelerate CA-MRSA transmission in the community.

Efficacy and safety of linezolid in immunocompromised children with cancer

BACKGROUND

The aim of this study was to determine the safety, tolerance and efficacy of linezolid for the treatment of infections from Gram-positive bacteria in immunocompromised children with cancer.

METHODS

This was a prospective non-comparative unblinded study in the Hematology/Oncology Unit over a two-year period, administering linezolid as monotherapy in children with cancer.

RESULTS

Seventeen children received linezolid (30 mg/kgr: 3 i.v. per day). Mean duration of linezolid administration was 12.2 days (range, 6-38 days), while the median age of the evaluable patients was 2.2 years (range, 6 months-11.2 years). Primary diagnosis was acute lymphoblastic leukemia (nine patients), brain tumor (three patients), multi-organ Langerhans cell histiocytosis (two patients), rhabdomyosarcoma, Burkitt's lymphoma and ovarian tumor (one patient each). All patients were in the midst of chemotherapy cycles. Ten out of 17 children had positive blood cultures (methicillin-resistant Staphylococcus aureus, four patients; vancomycin-resistant Enterococcus, three patients; penicillin-resistant Streptococcus pneumoniae, three patients), while seven of the 17 had fever and vancomycin-resistant Enterococcus in stool cultures. All patients were considered clinically cured after the end of the linezolid regimen (100% efficacy). The main adverse events were thrombocytopenia grade 1-3 and anemia grade 2-3 (four and two patients, respectively). Chemotherapy-induced myelotoxicity (six patients) was not worsened during linezolid therapy. No bleeding episodes were presented. Self-limited diarrhea grade 1-2 was presented in four patients (mean duration 2 days). The total adverse event rate was 23.5%; however, there was no premature cessation of linezolid in any patient.

CONCLUSIONS

Linezolid may be another effective and safe therapy to treat infections from resistant Gram-positive bacteria in immunocompromised children, even in young ages.

Management of acute hematogenous osteomyelitis in children

In children, osteomyelitis is primarily hematogenous in origin and acute in nature. The principal cause of osteomyelitis in children is Staphylococcus aureus, and both the epidemiology and pathogenesis of S. aureus infections, including osteomyelitis, have changed in recent years owing to the emergence of community-associated methicillin-resistant S. aureus. This review focuses on advances in the diagnosis and overall management of acute hematogenous osteomyelitis in children with these changes in mind.

Diagnosis and management of community-associated MRSA infections in children

The history of antibiotic resistance in Staphylococcus aureus spans more than half a century. Methicillin-resistant S. aureus (MRSA) has emerged as an almost ubiquitous pathogen in both the community and hospital settings. The predominant clone responsible for community-associated MRSA, USA300, is a highly successful pathogen, as demonstrated by its rapid global spread and associated morbidity and mortality. The management of MRSA infections in pediatric patients is complicated by the limited number of effective antibiotics that have been well-studied in children. The gold standard antimicrobial, vancomycin, has several shortcomings that have prompted the development of newer agents for the treatment of MRSA disease. Moreover, the emergence of vancomycin-intermediate or -resistant S. aureus, while uncommon, portends a potential new era of resistance that will require research and development of the next generation of antibiotics that act by novel mechanisms.

Clinical efficacy and tolerability of linezolid in pediatric patients: a systematic review

BACKGROUND

Linezolid is marketed for the treatment of severe, vancomycin-resistant infections with gram-positive bacteria in adults. Most information regarding the pharmacokinetic profile, efficacy, and tolerability of linezolid is derived from adult studies.

OBJECTIVE

The aim of this review was to summarize evidence regarding the use of linezolid in infants and children, focusing on the drug's clinical efficacy data and tolerability profile.

METHODS

A literature search was conducted of the Cochrane Library, EMBASE, and MEDLINE databases, from their inception through July 20, 2009, using the following terms: linezolid, newborn, infant, child, pediatrics, adolescent, human, clinical trial, and case report. Articles were excluded if they were redundant or not pertinent. (Articles that did not focus on the use of linezolid in children were considered not pertinent.) Bibliographies of all relevant articles were also evaluated.

RESULTS

Forty-seven publications regarding the use of linezolid in children were included in the review: 5 pharmacokinetic studies, 32 case reports, 6 randomized clinical trials (RCTs), 2 uncontrolled trials, 1 subanalysis of 2 published RCTs, and 1 subanalysis of published data about linezolid's tolerability. Pharmacokinetic data on linezolid use in children were derived from studies that enrolled 447 children. Plasma pharmacokinetics of linezolid in pediatric patients were found to be age dependent. Results from 6 vancomycinor cefadroxil-controlled RCTs (including 1480 children) evaluating linezolid treatment in children reported variable clinical cure rates, ranging from 75.0% to 93.2% in children with skin and skin-structure infections and from 77.5% to 90.0% in children with bacteremia or pneumonia. No significant difference in clinical cure rates between the linezolid group and the comparator group was observed in any study. The most frequently reported adverse events were diarrhea (from 3.1% to 16.8%), nausea and/or vomiting (from 2.9% to 11.9%), and thrombocytopenia (from 1.9% to 4.7%). To date, 3 cases of neuropathy have been described in children.

CONCLUSIONS

The reviewed pediatric studies in skin and skin-structure infections, bacteremia, or pneumonia found that linezolid was associated with high clinical cure rates (75.0%-93.2%) that did not differ significantly from those of vancomycin or cefadroxil. RCTs enrolling children with other types of infection (eg, osteomyelitis, endocarditis), as well as long-term studies, are needed to draw definitive conclusions about linezolid's efficacy and tolerability in pediatric patients. Careful monitoring for adverse events and possible linezolid resistance continues to be essential.

Linezolid therapy for pediatric thoracic spondylodiscitis due to Staphylococcus aureus sepsis

We report the case of an immunocompetent child with spondylodiscitis as a result of staphylococcal sepsis, which was successfully treated with linezolid. The patient was admitted with fever and circumferential swelling in the paradorsal region, which was evident only in the flexed back position. A chest X-ray showed a pleural effusion with pneumonitis and dorsal kyphosis. Following the yield of Staphylococcus aureus from blood cultures, the initial therapy of ceftriaxone and amikacin was changed to vancomycin. However, the dorsal swelling increased further and imaging investigations showed destruction of the vertebral bodies D8-D10 and surrounding tissue swelling. Vancomycin was changed to linezolid, and the patient began to improve; a full recovery was made. Our case suggests that even if spondylodiscitis is rare in the pediatric age-group, particularly as a complication of staphylococcal sepsis, early diagnosis and prompt and appropriate therapy are important to prevent severe complications.

Molecular and phenotypic characteristics of methicillin-resistant and vancomycin-intermediate staphylococcus aureus isolates from patients with septic arthritis

Staphylococcus aureus is one of the most common pathogens in community- and hospital-associated infections and frequently causes severe and intractable infections in osteoarticular tissues. S. aureus isolates that are resistant to methicillin (meticillin) (MRSA isolates) and intermediately resistant to vancomycin (VISA isolates) have emerged. In this report, we described two patients, one female and one male, diagnosed with septic arthritis due to S. aureus infections. A total of 13 MRSA isolates were obtained from these two patients. All but one isolate belonged to the VISA group. All seven isolates from the female patient were determined to be community associated, multilocus sequence type (MLST) 59, and staphylococcal cassette chromosome mecA (SCCmec) type IV; had direct repeat units (DRUs) of nine repeats; were spa type t437; and were susceptible to sulfa and quinolone antibiotics. The other six isolates, from the male patient, were determined to be hospital associated, MLST 239, and SCCmec type III; had DRUs of 14 repeats; were spa type t037; and were resistant to sulfa and quinolone antibiotics. All 13 MRSA isolates were in agr group I, were pvl negative, and showed no evidence of any association between vancomycin resistance and autolysis.

Peripheral neuropathy in an adolescent treated with linezolid

The increased incidence of methicillin-resistant Staphyloccocus aureus infections may increase linezolid use in children. Peripheral neuropathy is a rare adverse effect of linezolid therapy and is more frequent with prolonged courses. We present an adolescent with peripheral neuropathy after 4 months of linezolid therapy and review the literature related to linezolid-induced neuropathies. Children receiving long-term linezolid therapy should be monitored for neuropathy.

Empiric antibiotic therapy for acute osteoarticular infections with suspected methicillin-resistant Staphylococcus aureus or Kingella

The bacterial agents causing bone and joint infections have been changing. Currently, methicillin-resistant Staphylococcus aureus (MRSA) and Kingella kingae are emerging pathogens. For treatment of MRSA infections, clindamycin, vancomycin, and linezolid are commonly prescribed antibiotics. Kingella are sensitive to most penicillins and cephalosporins. Because MRSA osteoarticular infections tend to be severe, longer periods of antibiotic treatment with more frequent monitoring of inflammatory markers are sometimes required to obtain a complete cure with no residual complications. To assist management, we have included a clinical decision tree with antibiotic treatment protocols.