Antibiotic management of Staphylococcus aureus infections in US children's hospitals, 1999-2008

Optimal Teicoplanin Trough Concentration With Therapeutic Drug Monitoring in Children: A Systematic Review and Meta-analysis

BACKGROUND

Teicoplanin is used to treat serious Gram-positive bacterial infections. However, the optimal trough concentrations for pediatric patients remain unclear owing to the lack of monitoring guidelines. This study aimed to determine the optimal teicoplanin trough concentration for treating Gram-positive bacterial infections in children.

METHODS

A systematic review was conducted using 4 databases. Stepwise cutoffs within the range of 10-30 mcg/mL were used for efficacy and safety. Studies were included if they reported treatment success rates and/or all-cause mortality, nephrotoxicity, hepatotoxicity, and thrombocytopenia according to the trough concentration.

RESULTS

The meta-analysis included 12 studies involving 830 pediatric patients. Teicoplanin cutoff values of 10, 15, 20, and 30 mcg/mL were reported in 9, 8, 9, and 2 studies, respectively. Trough concentrations <10 mcg/mL significantly reduced the treatment success rate, with an odds ratio of 0.07 and a 95% confidence interval ranging from 0.01 to 0.40. The overall treatment success rate was 50.0% versus 95.7% observed at concentrations ≥10 mcg/mL. However, no significant difference was observed at the 15-, 20-, and 30-mcg/mL cutoffs, when compared with lower concentrations. Trough concentrations <20 mcg/mL were associated with a decreased risk of nephrotoxicity (odds ratio = 0.21; 95% confidence interval, 0.08-0.55). However, hepatotoxicity and thrombocytopenia showed no significant associations with trough concentration ranges between 10 and 30 mcg/mL.

CONCLUSIONS

Although further prospective studies are required for validation, the authors' findings suggest that 10- to 20-mcg/mL teicoplanin is the optimal trough concentration for enhanced clinical success and reduced toxicity in pediatric patients.

Metagenomic insights into isolable bacterial communities and antimicrobial resistance in airborne dust from pig farms

This study aims to investigate bacterial communities and antimicrobial resistance (AMR) in airborne dust from pig farms. Airborne dust, pig feces and feed were collected from nine pig farms in Thailand. Airborne dust samples were collected from upwind and downwind (25 meters from pig house), and inside (in the middle of the pig house) of the selected pig house. Pig feces and feed samples were individually collected from the pen floor and feed trough from the same pig house where airborne dust was collected. A direct total bacteria count on each sampling plate was conducted and averaged. The ESKAPE pathogens together with Escherichia coli, Salmonella, and Streptococcus were examined. A total of 163 bacterial isolates were collected and tested for MICs. Pooled bacteria from the inside airborne dust samples were analyzed using Metagenomic Sequencing. The highest bacterial concentration (1.9-11.2 × 103 CFU/m3) was found inside pig houses. Staphylococcus (n = 37) and Enterococcus (n = 36) were most frequent bacterial species. Salmonella (n = 3) were exclusively isolated from feed and feces. Target bacteria showed a variety of resistance phenotypes, and the same bacterial species with the same resistance phenotype were found in airborne dust, feed and fecal from each farm. Metagenomic Sequencing analysis revealed 1,652 bacterial species across all pig farms, of which the predominant bacterial phylum was Bacillota. One hundred fifty-nine AMR genes of 12 different antibiotic classes were identified, with aminoglycoside resistance genes (24%) being the most prevalent. A total of 251 different plasmids were discovered, and the same plasmid was detected in multiple farms. In conclusion, the phenotypic and metagenomic results demonstrated that airborne dust from pig farms contained a diverse array of bacterial species and genes encoding resistance to a range of clinically important antimicrobial agents, indicating the significant role in the spread of AMR bacterial pathogens with potential hazards to human health. Policy measurements to address AMR in airborne dust from livestock farms are mandatory.

Vancomycin Use in Children and Neonates across Three Decades: A Bibliometric Analysis of the Top-Cited Articles

Vancomycin is frequently prescribed in pediatrics, especially in intensive care unit settings, to treat Gram-positive bacterial infections. This work aims to collect the top-cited articles of pediatric and infectious diseases areas to gather the current evidence and gaps of knowledge on the use of vancomycin in these populations. The most relevant journals reported in the "pediatrics" and "infectious diseases" categories of the 2019 edition of Journal Citation Reports were browsed. Articles with more than 30 citations and published over the last three decades were collected. A bibliometric analysis was performed and 115 articles were retrieved. They were published in 21 journals, with a median impact factor of 4.6 (IQR 2.9-5.4). Sixty-eight of them (59.1%) belonged to "infectious diseases" journals. The most relevant topic was "bloodstream/complicated/invasive infections", followed by "antibiotic resistance/MRSA treatment". As for population distribution, 27 articles were on children only and 27 on neonates, most of which were from intensive care unit (ICU) settings. The current literature mainly deals with vancomycin as a treatment for severe infections and antibiotic resistance, especially in neonatal ICU settings. Lately, attention to new dosing strategies in the neonatal and pediatric population has become a sensible topic.

Prevalence of methicillin-resistant Staphylococcus aureus in Iranian children: a systematic review and meta-analysis

BACKGROUND

Antibiotic resistance is associated with longer hospitalizations, higher treatment costs, and increased morbidity and mortality rates.

PURPOSE

This study aimed to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Iranian children.

METHODS

International databases, including Web of Science, PubMed, Embase, and Scopus, and Iranian databases, including Scientific Information Database (www.sid.ir), Magiran, and Iranian Database for Medical Literature (idml.research.ac.ir), were systematically searched for articles published between January 2000 and August 2019. Sources of heterogeneity were determined using subgroup analysis and meta-regression.

RESULTS

Overall, 343 studies were identified; of them, 20 were included in the meta-analysis to estimate the pooled prevalence. The pooled prevalence of MRSA was 42% (95% confidence interval [CI], 29-55) among culture-positive cases of S. aureus, 51% (95% CI, 39-62) in hospitalized children, and 14% (95% CI, 0.05-27) in healthy children.

CONCLUSION

The overall pooled prevalence of MRSA in children was 42%. Appropriate infection control measures and effective antibiotic therapy are needed.

Reduced Vancomycin Susceptibility, MRSA and Treatment Failure in Pediatric Staphylococcus aureus Bloodstream Infections

BACKGROUND

Clinical implications of reduced vancomycin susceptibility (RVS) among pediatric Staphylococcus aureus bloodstream infections are unknown.

METHODS

We identified all children at 2 children's hospitals with ≥1 blood culture positive for S. aureus. We compared patient and clinical factors for RVS and non-RVS infections using Wilcoxon rank-sum and chi-squared tests. Treatment failure and the duration of bacteremia for RVS versus non-RVS and for methicillin-resistant Staphylococcus aureus (MRSA) versus methicillin-susceptible Staphylococcus aureus (MSSA) infections were compared using multivariable logistic and Poisson regressions, respectively. For MRSA infections, the association of empiric vancomycin monotherapy with treatment failure was assessed using multivariable logistic regression.

RESULTS

RVS was present in 72% (309/426) of cases. No patient or infection characteristics, including methicillin resistance, were associated with RVS. RVS was associated with an increased duration of bacteremia compared with non-RVS infections, aIRR = 1.15 (95% confidence interval: 1.02-1.30). The odds of treatment failure was similar for RVS and non-RVS infections, aOR = 1.04 (0.62-1.74). In contrast, MRSA infections were more likely to have treatment failure than MSSA infections, aOR = 3.03 (95% confidence interval: 1.84-5.00). For MRSA infections, empiric vancomycin monotherapy was associated with an increased odds of treatment failure compared with non-vancomycin or combination anti-MRSA antibiotics, aOR = 3.23 (1.12-9.26).

CONCLUSIONS

RVS was common and was associated with a longer duration of bacteremia but not with treatment failure. Treatment failure was more common for MRSA than for MSSA bloodstream infections. Empiric vancomycin monotherapy increased the odds of treatment failure for MRSA infections.

A cluster randomized stepped-wedge trial to de-implement unnecessary post-operative antibiotics in children: the optimizing perioperative antibiotic in children (OPerAtiC) trial

BACKGROUND

Antibiotic-resistant infections have become a public health crisis that is driven by the inappropriate use of antibiotics. In the USA, antibiotic stewardship programs (ASP) have been established and are required by regulatory agencies to help combat the problem of antibiotic resistance. Post-operative antibiotic use in surgical cases deemed low-risk for infection is an area with significant overuse of antibiotics in children. Consensus among leading public health organizations has led to guidelines eliminating post-operative antibiotics in low-risk surgeries. However, the best strategies to de-implement these inappropriate antibiotics in this setting are unknown.

METHODS/DESIGN

A 3-year stepped wedge cluster randomized trial will be conducted at nine US Children's Hospitals to assess the impact of two de-implementation strategies, order set change and facilitation training, on inappropriate post-operative antibiotic prescribing in low risk (i.e., clean and clean-contaminated) surgical cases. The facilitation training will amplify order set changes and will involve a 2-day workshop with antibiotic stewardship teams. This training will be led by an implementation scientist expert (VRM) and a pediatric infectious diseases physician with antibiotic stewardship expertise (JGN). The primary clinical outcome will be the percentage of surgical cases receiving unnecessary post-operative antibiotics. Secondary clinical outcomes will include the rate of surgical site infections and the rate of Clostridioides difficile infections, a common negative consequence of antibiotic use. Monthly semi-structured interviews at each hospital will assess the implementation process of the two strategies. The primary implementation outcome is penetration, which will be defined as the number of order sets changed or developed by each hospital during the study. Additional implementation outcomes will include the ASP team members' assessment of the acceptability, appropriateness, and feasibility of each strategy while they are being implemented.

DISCUSSION

This study will provide important information on the impact of two potential strategies to de-implement unnecessary post-operative antibiotic use in children while assessing important clinical outcomes. As more unnecessary medical practices are identified, de-implementation strategies, including facilitation, need to be rigorously evaluated. Along with this study, other rigorously designed studies evaluating additional strategies are needed to further advance the burgeoning field of de-implementation.

TRIAL REGISTRATION

NCT04366440. Registered April 28, 2020, https://clinicaltrials.gov/ct2/show/NCT04366440 .

Understanding antibiotic prophylaxis prescribing in pediatric surgical specialties

BACKGROUND

Overuse of antibiotics has caused secondary poor outcomes and has led to a current rate of antibiotic resistant infections that constitutes a public health crisis. In pediatric surgical specialties, children continue to receive unnecessary antibiotics.

OBJECTIVE

To understand the factors that contribute to pediatric surgeons' decisions regarding the use of perioperative antibiotic prophylaxis.

METHODS

Focus groups included pediatric proceduralists/surgeons from the following specialties: interventional cardiology, otolaryngology, orthopedic surgery, cardiothoracic surgery, and general surgery.

RESULTS

A total of 23 surgeons with a median of 9 years of experience (range, 0.5-29 years) participated in the focus groups that lasted 30-90 minutes each. Five themes emerged influencing beliefs about antibiotic prescribing practices: (1) reliance on previous experience and early education, (2) balancing antibiotic use with risk of infection, (3) uncertainty about the state of the scientific evidence, (4) understanding importance of communication and team collaboration, and (5) a prevalence of hospital-level concerns.

CONCLUSIONS

Surgeons describe a complex set of factors that impact their antibiotic prescribing in pediatric surgical cases. They reported initial, but not ongoing, training and a use of individual weight of risk and benefit as a major dictator of prescribing practices. Antimicrobial stewardship programs should work with surgeons to develop acceptable implementation strategies to optimize antibiotic prescribing.

State-of-the-Art Review on Physiologically Based Pharmacokinetic Modeling in Pediatric Drug Development

Physiologically based pharmacokinetic modeling and simulation is an important tool for predicting the pharmacokinetics, pharmacodynamics, and safety of drugs in pediatrics. Physiologically based pharmacokinetic modeling is applied in pediatric drug development for first-time-in-pediatric dose selection, simulation-based trial design, correlation with target organ toxicities, risk assessment by investigating possible drug-drug interactions, real-time assessment of pharmacokinetic-safety relationships, and assessment of non-systemic biodistribution targets. This review summarizes the details of a physiologically based pharmacokinetic modeling approach in pediatric drug research, emphasizing reports on pediatric physiologically based pharmacokinetic models of individual drugs. We also compare and contrast the strategies employed by various researchers in pediatric physiologically based pharmacokinetic modeling and provide a comprehensive overview of physiologically based pharmacokinetic modeling strategies and approaches in pediatrics. We discuss the impact of physiologically based pharmacokinetic models on regulatory reviews and product labels in the field of pediatric pharmacotherapy. Additionally, we examine in detail the current limitations and future directions of physiologically based pharmacokinetic modeling in pediatrics with regard to the ability to predict plasma concentrations and pharmacokinetic parameters. Despite the skepticism and concern in the pediatric community about the reliability of physiologically based pharmacokinetic models, there is substantial evidence that pediatric physiologically based pharmacokinetic models have been used successfully to predict differences in pharmacokinetics between adults and children for several drugs. It is obvious that the use of physiologically based pharmacokinetic modeling to support various stages of pediatric drug development is highly attractive and will rapidly increase, provided the robustness and reliability of these techniques are well established.

Bioavailability testing of a newly developed clindamycin oral suspension in a pediatric porcine model

Background: Clindamycin's bitter taste and odor is known to affect treatment adherence in children. Recently, a formulation of clindamycin HCl complexed with ion exchange resin IRP 69 was shown to mask the bitter taste. Because of the potential benefit of this formulation for children, a pilot study using a porcine model was conducted to evaluate its relative bioavailability. Methods: A randomized two-way crossover study design using six (n = 6) healthy male piglets 10-12 kg was used to evaluate the absorption profiles and pharmacokinetic parameters of clindamycin from the resinate complex formulation (Test) compared to a commercialized reference suspension. A dose of 15 mg/kg was administered orally by gastric gavage to each piglet followed by repeated blood sampling over 12 h. A wash-out period of 48 h occurred between treatments. Plasma concentration vs. time data was analyzed by non-compartmental analysis. Results: The mean relative bioavailability of clindamycin from the resinate formulation was 78.8%. A two-tailed, paired Student t test yielded a p < 0.05 for AUC∞ and Tmax parameters. A two one-sided test (TOST) suggested a difference in AUC∞ and Cmax for the Test formulation compared to the reference formulation according to the FDA's criteria for bioequivalence. Conclusion: The bioavailability of clindamycin from this novel oral formulation supports continued evaluation of the drug in humans for potential pediatric applications.

Increasing Clindamycin and Trimethoprim-Sulfamethoxazole Resistance in Pediatric Staphylococcus aureus Infections

The epidemiology of Staphylococcus aureus infection in children is dynamic. We conducted a retrospective observational study on pediatric clinical cultures, performed between 2005 and 2017, that grew S aureus to determine temporal trends in antibiotic resistance. Although methicillin resistance declined, clindamycin and trimethoprim-sulfamethoxazole resistance increased significantly, especially among community-onset isolates.

Recent advances in Staphylococcus aureus infection: focus on vaccine development

Staphylococcus aureus normally colonizes the nasal cavity and pharynx. After breaching the normal habitat, the organism is able to cause a number of infections at any site of the body. The development of antibiotic resistance has created a global challenge for treating infections. Therefore, protection by vaccines may provide valuable measures. Currently, several vaccine candidates have been prepared which are either in preclinical phase or in early clinical phase, whereas several candidates have failed to show a protective efficacy in human subjects. Approaches have also been made in the development of monoclonal or polyclonal antibodies for passive immunization to protect from S. aureus infections. Therefore, in this review we have summarized the findings of recently published scientific literature to make a concise report.

Antibiotic Resistance and the MRSA Problem

Staphylococcus aureus is capable of becoming resistant to all classes of antibiotics clinically available and resistance can develop through de novo mutations in chromosomal genes or through acquisition of horizontally transferred resistance determinants. This review covers the most important antibiotics available for treatment of S. aureus infections and a special emphasis is dedicated to the current knowledge of the wide variety of resistance mechanisms that S. aureus employ to withstand antibiotics. Since resistance development has been inevitable for all currently available antibiotics, new therapies are continuously under development. Besides development of new small molecules affecting cell viability, alternative approaches including anti-virulence and bacteriophage therapeutics are being investigated and may become important tools to combat staphylococcal infections in the future.

A decade of antimicrobial resistance in Staphylococcus aureus: A single center experience

Background

The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) resulted in the recommended use of clindamycin and trimethoprim-sulfamethoxazole (TMP-SMX) for suspected S. aureus infections. The objective of this study was to determine the resistance to methicillin, clindamycin, and TMP-SMX in S. aureus isolates during a 10-year period.

Methods

Retrospective review of the antimicrobial susceptibilities of all S. aureus isolates in the outpatient and inpatient settings at Nationwide Children’s Hospital from 1/1/2005 to 12/31/2014. Duplicate isolates from the same site and year and those obtained for MRSA surveillance or from patients with cystic fibrosis were excluded.

Results

Of the 57,788 S. aureus isolates from 2005–2014, 40,795 (71%) were included. In the outpatient setting, methicillin resistance decreased from 54% to 44% (p<0.001) while among inpatient isolates, no significant change was observed. From 2009–2014, resistance to clindamycin among outpatient isolates increased from 16% to 17% (p = 0.002) but no significant trend was observed among inpatient isolates (18% to 22%). Similarly, TMP-SMX resistance increased in outpatient S. aureus isolates from 2005–2014 (0.9% to 4%, p<0.001) but not among inpatient isolates. Among both inpatient and outpatient isolates, methicillin-susceptible S. aureus (MSSA) exhibited higher resistance to both clindamycin and TMP-SMX than MRSA. In addition, resistance to methicillin, clindamycin and TMP-SMX varied widely according to the site of specimen collection.

Conclusion

In a decade where >40,000 S. aureus isolates were identified at a large pediatric hospital, substantial changes in methicillin, clindamycin, and TMP-SMX resistance occurred. These findings highlight the importance of ongoing surveillance of the local antimicrobial resistance in S. aureus in order to guide empiric antimicrobial therapy.

Epidemiology of Staphylococcus aureus infections in patients admitted to freestanding pediatric hospitals, 2009-2016

We observed pediatric S. aureus hospitalizations decreased 36% from 26.3 to 16.8 infections per 1,000 admissions from 2009 to 2016, with methicillin-resistant S. aureus (MRSA) decreasing by 52% and methicillin-susceptible S. aureus decreasing by 17%, among 39 pediatric hospitals. Similar decreases were observed for days of therapy of anti-MRSA antibiotics.

Experience with developing antibiotic stewardship programs in Serbia: potential model for other Balkan countries?

Aim: Antimicrobial resistance and inappropriate use of antibiotics in children are important issues. Consequently, there is a need to develop comprehensive stewardship programs even in hospitals with limited resources starting with children's hospitals. Methods: Retrospective observational analysis of antimicrobial utilization and resistance patterns over 5 years in a tertiary care children's hospital in Serbia. Results: Cumulative antimicrobial resistance decreased but was still high, with high cumulative resistance rates among the most widely used antibiotics in the hospital. Total antibiotic use decreased from 2010 to 2014 although there was still high prescribing of reserved antibiotics. Conclusion: Concerns with inappropriate use and high resistance rates among some antibiotics used in the hospital are being used to develop guidance on future antibiotic use in this hospital, building on the recently introduced antibiotic stewardship program, as well as encourage other hospitals in Serbia to review their policies.

Development of a Pediatric Physiologically-Based Pharmacokinetic Model of Clindamycin Using Opportunistic Pharmacokinetic Data

Physiologically-based pharmacokinetic (PBPK) modeling is a powerful tool used to characterize maturational changes in drug disposition to inform dosing across childhood; however, its use is limited in pediatric drug development. Access to pediatric pharmacokinetic data is a barrier to widespread application of this model, which impedes its development and optimization. To support the development of a pediatric PBPK model, we sought to leverage opportunistically-collected plasma concentrations of the commonly used antibiotic clindamycin. The pediatric PBPK model was optimized following development of an adult PBPK model that adequately described literature data. We evaluated the predictability of the pediatric population PBPK model across four age groups and found that 63-93% of the observed data were captured within the 90% prediction interval of the model. We then used the pediatric PBPK model to optimize intravenous clindamycin dosing for a future prospective validation trial. The optimal dosing proposed by this model was 9 mg/kg/dose in children ≤5 months of age, 12 mg/kg/dose in children >5 months-6 years of age, and 10 mg/kg/dose in children 6-18 years of age, all administered every 8 h. The simulated exposures achieved with the dosing regimen proposed were comparable with adult plasma and tissue exposures for the treatment of community-acquired methicillin-resistant Staphylococcus aureus infections. Our model demonstrated the feasibility of using opportunistic pediatric data to develop pediatric PBPK models, extending the reach of this powerful modeling tool and potentially transforming the pediatric drug development field.

Pharmacokinetics of Clindamycin in Obese and Nonobese Children

Although obesity is prevalent among children in the United States, pharmacokinetic (PK) data for obese children are limited. Clindamycin is a commonly used antibiotic that may require dose adjustment in obese children due to its lipophilic properties. We performed a clindamycin population PK analysis using data from three separate trials. A total of 420 samples from 220 children, 76 of whom had a body mass index greater than or equal to the 95th percentile for age, were included in the analysis. Compared to other metrics, total body weight (TBW) was the most robust measure of body size. The final model included TBW and a sigmoidal maturation relationship between postmenstrual age (PMA) and clearance (CL): CL (liters/hour) = 13.8 × (TBW/70)0.75 × [PMA2.83/(39.52.83+PMA2.83)]; volume of distribution (V) was associated with TBW, albumin (ALB), and alpha-1 acid glycoprotein (AAG): V (liters) = 63.6 × (TBW/70) × (ALB/3.3)-0.83 × (AAG/2.4)-0.25 After accounting for differences in TBW, obesity status did not explain additional interindividual variability in model parameters. Our findings support TBW-based dosing for obese and nonobese children.

Sequential Parenteral to Oral Clindamycin Dosing in Pediatric Musculoskeletal Infection: A Retrospective Review of 30 mg/kg/d Versus 40 mg/kg/d

BACKGROUND

Children with musculoskeletal infection in methicillin-resistant Staphylococcus aureus (MRSA) prevalent communities are often treated with oral clindamycin. Current guidelines recommend approximately 40 mg/kg/d for MRSA infections. This study investigates the clinical practice of using 30 mg/kg/d of clindamycin as an alternative for outpatient dosing.

METHODS

Children with musculoskeletal infection treated with outpatient clindamycin from 2009 to 2014 were studied by retrospective review. The amount of clindamycin administered was determined from dose, interval and duration of outpatient treatment. Hospital readmission, surgeries and sequelae were assessed. Severity of illness was determined for children with osteomyelitis. The readmission rate of 25 children treated with 40 mg/kg/d was compared with that of 190 children treated with 30 mg/kg/d. The reason for readmission was evaluated to consider whether antibiotic dosing strategy was a potential factor.

RESULTS

Among 215 children studied, the average outpatient duration of treatment was 32.8 days. There was no significant difference in the rate of readmission between dosing cohorts. Severity of illness scores (0-10 scale) was significantly higher among readmitted children with osteomyelitis (mean 9.8 ± 0.4) than among those with osteomyelitis who were not readmitted (mean 2.9 ± 3.2), P = 0.001. Sequelae were more common in the high-dose group and were noted in 3 children (12%) in that cohort compared with 6 children (3.2%) in the low-dose cohort (P > 0.05).

CONCLUSION

Oral dosing of 30 mg/kg/d was effective for musculoskeletal infection in children in an MRSA prevalent community. Illness severity appeared to have greater impact on readmission and sequelae than did antibiotic dosing.

Prevalence and Characteristics of Antimicrobial Stewardship Programs at Freestanding Children's Hospitals in the United States

Background and Objective.

Antimicrobial stewardship programs (ASPs) are a mechanism to ensure the appropriate use of antimicrobials. The extent to which ASPs are formally implemented in freestanding children's hospitals is unknown. The objective of this study was to determine the prevalence and characteristics of ASPs in freestanding children's hospitals.

Methods.

We conducted an electronic survey of 42 freestanding children's hospitals that are members of the Children's Hospital Association to determine the presence and characteristics of their ASPs. For hospitals without an ASP, we determined whether stewardship strategies were in place and whether there were barriers to implementing a formal ASP.

Results.

We received responses from 38 (91%) of 42. Among responding institutions, 16 (38%) had a formal ASP, and 15 (36%) were in the process of implementing a program. Most ASPs (13 [81%] of 16) were started after 2007. The median number of full-time equivalents dedicated to ASPs was 0.63 (range, 0.1–1.8). The most common antimicrobials monitored by ASPs were linezolid, vancomycin, and carbapenems. Many hospitals without a formal ASP were performing stewardship activities, including elements of prospective audit and feedback (9 [41%] of 22), formulary restriction (9 [41%] of 22), and use of clinical guidelines (17 [77%] of 22). Antimicrobial outcomes were more likely to be monitored by hospitals with ASPs (100% vs 68%; P = .01), although only 1 program provided support for a data analyst.

Conclusions.

Most freestanding children's hospitals have implemented or are developing an ASP. These programs differ in structure and function, and more data are needed to identify program characteristics that have the greatest impact.

Clindamycin resistance among Staphylococcus aureus strains in Israel: implications for empirical treatment of skin and soft tissue infections

OBJECTIVES

The objectives of this study were to characterize isolates of Staphylococcus aureus obtained from skin and soft tissue infections in the community in Israel and to document the sensitivity patterns for commonly used antimicrobial agents.

METHODS

The susceptibilities of S. aureus isolates from skin and soft tissue infections in the community in Israel were reviewed to determine the appropriate empirical therapy for these infections.

RESULTS

A total of 7221 isolates were collected during the period 2009-2012; 39% were from children (age 0-18 years). In children, S. aureus oxacillin resistance dropped from 8.4% to 3.8% (p=0.073). While inducible clindamycin resistance increased slightly from 20% to 25%, there was a prominent increase in constitutive clindamycin resistance from 0.1% to 26.8% (p=0.012). In adults, oxacillin resistance increased from 16% to 23% (p<0.001) and constitutive clindamycin resistance increased notably from 5% to 29% (p<0.001). These findings demonstrate a dramatic increase in clindamycin resistance among S. aureus isolates and suggest against the usage of clindamycin as empirical treatment for suspected S. aureus infections in Israel.

CONCLUSIONS

Beta-lactam anti-staphylococcal agents may be given as empirical treatment for children, but should be considered according to risk factors for adults in Israel.

Risk Factors for Community-associated Clostridium difficile-associated Diarrhea in Children

BACKGROUND

Clostridium difficile-associated diarrhea (CDAD) is increasingly diagnosed in children in community settings. This study aims to assess recent antibiotic use and other risk factors in children with community-associated (CA-) CDAD compared with children with other diarrheal illnesses in a tertiary care setting.

METHODS

Children with CA-CDAD evaluated at Texas Children's Hospital (Houston, TX) from January 1, 2012 to June 30, 2013 were identified. Two control subjects with community-associated diarrhea who tested negative for C. difficile were matched to case subjects. Data on demographics, medication exposure and outpatient healthcare encounters were collected from medical records. Multivariate logistic regression was performed to identify predictors of pediatric CA-CDAD.

RESULTS

Of 69 CA-CDAD cases, most (62.3%) had an underlying chronic medical condition and 40.6% had antibiotic exposure within 30 days of illness. However, no traditional risk factor for CDAD was identified in 23.2% and 15.9% of CA-CDAD cases within 30 and 90 days of illness onset, respectively. Outpatient healthcare encounters within 30 days were more common among CA-CDAD cases than control subjects (66.7% vs. 48.6%; P = 0.01). In the final multivariate model, CA-CDAD was associated with cephalosporin use within 30 days [odds ratio: 3.32; 95% confidence interval: 1.10-10.01] and the presence of a gastrointestinal feeding device (odds ratio: 2.59; 95% confidence interval: 1.07-6.30).

CONCLUSIONS

Recent use of cephalosporins and the presence of gastrointestinal feeding devices are important risk factors for community- associated CDAD in children. Reduction in the use of outpatient antibiotics may decrease the burden of CA-CDAD in children.

Scratching the surface: a review of skin and soft tissue infections in children

PURPOSE OF REVIEW

We present data from recently conducted research on the diagnosis and management of skin and soft tissue infections (SSTIs) in children.

RECENT FINDINGS

Current research in the area of SSTIs (cellulitis and abscess) has focused on the use of ultrasound, risk factors associated with bacteremia, antibiotic choice, and incision and drainage (I&D) practices. When clinical examination is equivocal at distinguishing abscess from cellulitis, ultrasound can aid in the diagnosis and alter management. Bacteremia is rare in immunocompetent children with uncomplicated SSTIs; blood cultures may be reserved for complicated cases and for those who are systemically ill. Despite the increased prevalence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), I&D without antibiotics remains the first-line therapy for abscess. Antibiotics for uncomplicated cellulitis should target β-hemolytic streptococci and methicillin-susceptible S. aureus (MSSA). There are significant variations in pain and sedation practices for I&D, with substantive evidence for the use of topical anesthetics. Wound packing after I&D may not confer significant benefit.

SUMMARY

Evidence to aid in the diagnosis and management of SSTIs in children has emerged in recent years; however, larger prospective pediatric studies are needed.

Simultaneous determination of trimethoprim and sulfamethoxazole in dried plasma and urine spots

BACKGROUND

Trimethoprim-sulfamethoxazole (TMP-SMX) is an antimicrobial drug combination commonly prescribed in children and adults. The study objectives were to validate and apply an HPLC-MS/MS method to quantify TMP-SMX in dried plasma spots (DPS) and dried urine spots (DUS), and perform a comparability analysis with liquid matrices.

RESULTS

For TMP the validated range was 100-50,000 ng/ml for DPS and 500-250,000 ng/ml for DUS; for SMX, the validated range was 1000-500,000 ng/ml for both DPS and DUS. Good agreement was noted between DPS/DUS and liquid plasma and urine samples for TMP, while only modest agreement was observed for SMX in both matrices.

CONCLUSION

A precise, accurate and reproducible method was developed to quantify TMP-SMX in DPS and DUS samples.

Use of opportunistic clinical data and a population pharmacokinetic model to support dosing of clindamycin for premature infants to adolescents

Clindamycin is commonly prescribed to treat children with skin and skin-structure infections (including those caused by community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA)), yet little is known about its pharmacokinetics (PK) across pediatric age groups. A population PK analysis was performed in NONMEM using samples collected in an opportunistic study from children receiving i.v. clindamycin per standard of care. The final model was used to optimize pediatric dosing to match adult exposure proven effective against CA-MRSA. A total of 194 plasma PK samples collected from 125 children were included in the analysis. A one-compartment model described the data well. The final model included body weight and a sigmoidal maturation relationship between postmenstrual age (PMA) and clearance (CL): CL (l/h) = 13.7 × (weight/70)(0.75) × (PMA(3.1)/(43.6(3.1) + PMA(3.1))); V (l) = 61.8 × (weight/70). Maturation reached 50% of adult CL values at ~44 weeks PMA. Our findings support age-based dosing.

Clinical characteristics and antibiotic utilization in pediatric patients hospitalized with acute bacterial skin and skin structure infection

BACKGROUND

Hospitalizations for acute bacterial skin and skin structure infection (ABSSSI) in children are increasingly frequent, but little is known about antibiotic utilization. In adults, recent studies suggest substantial opportunity to reduce broad-spectrum antibiotic use and shorten therapy. We sought to determine whether similar opportunity exists in children.

METHODS

This was a planned secondary analysis of a pediatric cohort taken from a multicenter, retrospective cohort of patients hospitalized for ABSSSI between June 1, 2010, and May 31, 2012. The prespecified primary endpoint was a composite of 2 prescribing practices: (1) use of antibiotics with broad Gram-negative activity or (2) treatment duration >10 days.

RESULTS

One-hundred and two patients ≤ 18 years old were included: 43 had non-purulent cellulitis, 19 had wound infection or purulent cellulitis and 40 had cutaneous abscess. The median age was 5 years (range 45 days to 18 years). Clindamycin was the most frequently prescribed antibiotic during hospitalization (67% of cases) and at discharge (66% of cases). The median duration of therapy was 11 days (interquartile range 10-12) and was similar for all 3 types of ABSSSI. The primary endpoint occurred in 67% of cases, including broad Gram-negative therapy in 25% and treatment duration >10 days in 61%. By multivariate logistic regression, admission through an emergency department and management by a medical (vs. surgical) service were independently associated with the primary endpoint.

CONCLUSIONS

Children hospitalized for ABSSSI are frequently exposed to antibiotics with broad Gram-negative activity or treated longer than 10 days suggesting opportunity to reduce antibiotic use.

Staphylococcus aureus - antimicrobial resistance and the immunocompromised child

Children with immunocompromising conditions represent a unique group for the acquisition of antimicrobial resistant infections due to their frequent encounters with the health care system, need for empiric antimicrobials, and immune dysfunction. These infections are further complicated in that there is a relative paucity of literature on the clinical features and management of Staphylococcus aureus infections in immunocompromised children. The available literature on the clinical features, antimicrobial susceptibility, and management of S. aureus infections in immunocompromised children is reviewed. S. aureus infections in children with human immunodeficiency virus (HIV) are associated with higher HIV viral loads and a greater degree of CD4 T-cell suppression. In addition, staphylococcal infections in children with HIV often exhibit a multidrug resistant phenotype. Children with cancer have a high rate of S. aureus bacteremia and associated complications. Increased tolerance to antiseptics among staphylococcal isolates from pediatric oncology patients is an emerging area of research. The incidence of S. aureus infections among pediatric solid organ transplant recipients varies considerably by the organ transplanted; in general however, staphylococci figure prominently among infections in the early posttransplant period. Staphylococcal infections are also prominent pathogens among children with a number of immunodeficiencies, notably chronic granulomatous disease. Significant gaps in knowledge exist regarding the epidemiology and management of S. aureus infection in these vulnerable children.

Pharmacokinetics and safety of recently approved drugs used to treat methicillin-resistant Staphylococcus aureus infections in infants, children and adults

Methicillin-resistant Staphylococcus aureus (MRSA) remains a significant cause of morbidity in hospitalized infants. Over the past 15 years, several drugs have been approved for the treatment of S. aureus infections in adults (linezolid, quinupristin/dalfopristin, daptomycin, telavancin, tigecycline and ceftaroline). The use of the majority of these drugs has extended into the treatment of MRSA infections in infants, frequently with minimal safety or dosing information. Only linezolid is approved for use in infants, and pharmacokinetic data in infants are limited to linezolid and daptomycin. Pediatric trials are underway for ceftaroline, telavancin, and daptomycin; however, none of these studies includes infants. Here, we review current pharmacokinetic, safety and efficacy data of these drugs with a specific focus in infants.

Cutaneous bacterial infections caused by Staphylococcus aureus and Streptococcus pyogenes in infants and children

Acute bacterial skin and skin structure infections (SSSIs) are among the most common bacterial infections in children. The medical burden of SSSIs, particularly abscesses, has increased nationwide since the emergence of community-acquired methicillin-resistant Staphylococcus aureus. SSSIs represent a wide spectrum of disease severity. Prompt recognition, timely institution of appropriate therapy, and judicious antimicrobial use optimize patient outcomes. For abscesses, incision and drainage are paramount and might avoid the need for antibiotic treatment in uncomplicated cases. If indicated, empiric antimicrobial therapy should target Streptococcus pyogenes for nonpurulent SSSIs, such as uncomplicated cellulitis, and S aureus for purulent SSSIs such as abscesses.

Linezolid use in hospitalized children

We used the Pediatric Health Information System to evaluate linezolid use among hospitalized children. From 2003 to 2007, use increased 5-fold, including wide interhospital variation, then stabilized through 2011. Linezolid was responsible for 3% of total antibiotic expenditures. Children with respiratory, oncologic or transplant conditions were the most frequently treated with linezolid.

Antibiotic Management of Animal Bites in Children During the Methicillin-Resistant Staphylococcus aureus Era

Children presenting to an emergency department following an animal bite were found to be at risk for infection if they had puncture wounds, crush wounds, or were bitten by a cat. Of the infected wounds that were cultured, methicillin-resistant Staphylococcus aureus was not isolated as a pathogen.

Update on Epidemiology and Treatment of MRSA Infections in Children

In 2000-10 the epidemiology of pediatric MRSA infections in the United States was transformed with an epidemic of CA-MRSA infections. We review the epidemiology of MRSA in the community and in the health care setting, including intensive care units, among infants and CF patients, and in households as well as the impact that the CA-MRSA epidemic has had on hospitalization with MRSA infections. Risk factors for carriage, transmission, and initial and recurrent infection with MRSA are discussed. New studies on the treatment of pediatric MRSA infections and on the efficacy of MRSA decolonization are reviewed.

Antimicrobial susceptibility among Gram-positive organisms collected from pediatric patients globally between 2004 and 2011: results from the Tigecycline Evaluation and Surveillance Trial

The Tigecycline Evaluation and Surveillance Trial (TEST) was designed to monitor global longitudinal changes in bacterial susceptibility to a panel of antimicrobial agents, including tigecycline. In this study, we examine susceptibility among Gram-positive isolates collected from pediatric patients globally between 2004 and 2011. A total of 9,422 Gram-positive isolates were contributed by 1,255 centers, predominantly from Europe and North America. One-third of Staphylococcus aureus isolates were methicillin resistant, peaking in prevalence in 2007. All S. aureus isolates (n = 3,614) were susceptible to linezolid, tigecycline, and vancomycin; minocycline, imipenem, and meropenem were also highly active (>92% susceptibility). Ampicillin and penicillin susceptibility increased significantly during the study period (P < 0.0001 for both). Streptococcus pneumoniae isolates (n = 3,373) were highly susceptible to vancomycin (100%), linezolid (>99%), and levofloxacin and tigecycline (both >96%); imipenem susceptibility was low (32%) in Africa while minocycline susceptibility was low in Asia-Pacific Rim (38%). Penicillin resistance occurred in one-fifth of all S. pneumoniae isolates, with penicillin susceptibility ranging from 14% in Africa to 65% in Europe. Streptococcus agalactiae isolates (n = 1,056) were highly susceptible to most antimicrobials, although only 16% were susceptible to minocycline. Enterococcus faecalis isolates (n = 1,112) were highly susceptible (>97%) to ampicillin, linezolid, penicillin, tigecycline, and vancomycin globally, but only 34% were minocycline susceptible; minocycline susceptibility decreased significantly from 2004 to 2011 (P < 0.001). Tigecycline and linezolid were highly active against Enterococcus faecium (n = 267) globally (100% and 98% susceptible, respectively). Tigecycline and linezolid were highly active against Gram-positive pathogens from pediatric patients in TEST 2004 to 2011, with vancomycin and the carbapenems performing well against most pathogens.

Microbiology and antimicrobial treatment of pediatric cervical lymphadenitis requiring surgical intervention

BACKGROUND

Acute cervical lymphadenitis is a common condition often times requiring antibiotic therapy and possible surgical drainage. The objective of this study was to describe the clinical characteristics, diagnostic and therapeutic management of children requiring surgical drainage for acute cervical lymphadenitis.

METHODS

A retrospective, descriptive study was performed at a Midwestern US tertiary-care children's hospital on all immunocompetent children who underwent an incision and drainage procedure of cervical lymphadenitis from January 1999 to July 2009.

RESULTS

A total of 277 patients were identified. Males represented 51% and the median age was 28 months (IQR: 13-59). Lymphadenitis was unilateral in 243 (87.7%) cases and bilateral in 19 (6.9%). Median length of hospital stay was 4 days (IQR: 3-5). Aerobic, anaerobic, acid fast bacillus (AFB), and fungal cultures were obtained intraoperatively in 99%, 98%, 82%, and 78% of cases, respectively. However no fungal cultures were positive and only 1% of anaerobic and 2% of AFB cultures were positive. The most common bacterial etiology was Staphylococcus aureus (35.7%) and Streptococcus pyogenes (18.8%). Of all cultures, 32% were negative. Overall, 22% were positive for methicillin susceptible S. aureus (MSSA) and 13.7% for methicillin resistant S. aureus (MRSA), with 96% MSSA and 100% MRSA susceptible to clindamycin. Median duration of discharge antibiotics prescribed was 10 days (IQR: 7-11). Only 12 (4.5%) patients required a repeat incision and drainage within 3 months.

CONCLUSIONS

A single antibiotic that treats S. pyogenes and S. aureus should be the empiric antibiotic for cervical lymphadenitis requiring incision and drain. We recommend sending only aerobic cultures intraoperatively as a routine practice as other pathogens are rare.

Association of neighborhood-level factors with hospitalization for community-associated methicillin-resistant Staphylococcus aureus, New York City, 2006: a multilevel observational study

BACKGROUND

Hospitalizations with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection have increased in New York City, with substantial geographic variation across neighborhoods. While individual-level risk factors, such as age, sex, HIV infection, and diabetes have been described, the role of neighborhood-level factors (e.g., neighborhood HIV prevalence or income) has not been examined.

METHODS

To explore plausible neighborhood-level factors associated with CA-MRSA-related hospitalizations, a retrospective analysis was conducted using New York City hospital discharges from 2006 and New York City-specific survey and health department surveillance data. CA-MRSA-related hospitalizations were identified using diagnosis codes and admission information. Associations were determined by using sex-specific multilevel logistic regression.

RESULTS

The CA-MRSA hospitalization rate varied by more than six-fold across New York City neighborhoods. Females hospitalized with CA-MRSA had more than twice the odds of residing in neighborhoods in the highest quintile of HIV prevalence (adjusted odds ratio [AOR](Q5 vs. Q1) 2.3, 95% CI: 1.2, 2.7). Both males and females hospitalized with CA-MRSA had nearly twice the odds of residing in neighborhoods with moderately high proportion of men who have sex with men (MSM) residing in the neighborhood (males: AOR(Q4 vs. Q1) 1.7, 95% CI: 1.1, 2.7; females: AOR(Q4 vs. Q1) 2.0, 95% CI: 1.1, 3.6); but this association did not hold for neighborhoods in the highest quintile (males: AOR(Q5 vs. Q1) 1.2, 95% CI: 0.76, 1.8; females: AOR(Q5 vs. Q1) 1.5, 95% CI: 0.82, 2.7).

CONCLUSIONS

Neighborhood-level characteristics were associated with CA-MRSA hospitalization odds, independent of individual-level risk factors, and may contribute to the population-level burden of CA-MRSA infection.

Analysis of vancomycin therapeutic drug monitoring trends at pediatric hospitals

BACKGROUND

Vancomycin treatment failures in adults with methicillin-resistant Staphylococcus aureus bacteremia are well documented despite established therapeutic monitoring consensus recommendations. Vancomycin use in children has unique challenges, and consensus guidelines are lacking. We evaluated trends in vancomycin monitoring in children and estimated the impact of adult guidelines on patterns of vancomycin use.

METHODS

A retrospective, descriptive study was designed. Data were obtained from the Pediatric Health Information System from 40 not-for-profit, tertiary care pediatric hospitals in the United States. Patients receiving vancomycin during hospitalizations ending July 1, 2007 through June 30, 2011 were included, and the number of vancomycin monitoring determinations per course of therapy was queried. Vancomycin utilization and monitoring practices were evaluated across institutions, age groups and time intervals.

RESULTS

A total of 104,586 patients met study criteria. The mean duration of vancomycin administration was 5 (median 3, range 1-257) days. A mean of 1 (median 1, range 0-186) serum vancomycin concentration was obtained per patient; 46% of patients had none. Eighty-one percent of those receiving vancomycin more than 3 days had monitoring performed at least once. Monitoring practices did not correlate with length of therapy (r² = 0.11). Monitoring frequency increased across all age groups (P < 0.05) after publication of adult guidelines in January 2009.

CONCLUSIONS

Vancomycin monitoring practices are highly variable in children admitted to pediatric hospitals. The frequency with which serum vancomycin concentrations were monitored in children increased after the publication of the adult guidelines. Pediatric consensus guidelines should be developed to optimize patient care and resource utilization.

Trends of genital and nongenital community-acquired methicillin-resistant Staphylococcus aureus infections in an urban pediatric population

OBJECTIVE

The study aimed to identify etiologies and risk factors associated with any possible trends in the number of genital-region community-acquired methicillin-resistant Staphylococcus aureus (MRSA) infections among children and adolescents aged 1 to 18 years.

MATERIALS AND METHODS

Demographic, exposure, and treatment data were collected from patients with community-acquired MRSA-positive abscess fluid cultures obtained from inpatient, outpatient, and pediatric emergency department visits from 2004 to 2008. The data were analyzed using IBM SPSS for statistically significant trends or risk factors both within and between groups.

RESULTS

A statistically significant increase in the total number of MRSA abscesses as well as the proportion of genital to nongenital abscesses was observed in 2008 when compared with those of the previous 4 years (p = .026). This increase is largely due to an increase in affected male patients as genital MRSA infections among female patients remained stable. Methicillin-resistant S. aureus genital infections were more likely to occur in children with a history of MRSA infection (p = .017) and were most common in the age group 1 to 4 years. Both male and female patients with nongenital MRSA infections were more likely to have experienced recent surgery (p = .04). Female patients with nongenital abscess were twice as likely to have been recently hospitalized as those with genital MRSA infections (p = .02). No statistically significant differences were found in the rates of genital or nongenital abscesses between ethnic groups (p = .22). The rates of genital and nongenital abscesses differed in male and female patients, although these differences did not achieve statistical significance (p = .23).

CONCLUSIONS

Although the total number of genital infections has increased, infections among female children remain largely unchanged. Community-acquired methicillin-resistant S. aureus genital abscesses are more likely to be the result of colonization, rather than de novo infection, than nongenital abscesses. The effectiveness of individual treatment modalities and rates of recurrence are independent of abscess location, but genital abscesses may indicate the presence of resistant organisms, colonization, or both.

Rates and appropriateness of antimicrobial prescribing at an academic children's hospital, 2007-2010

OBJECTIVE AND DESIGN

Antimicrobial use in hospitalized children has not been well described. To identify targets for antimicrobial stewardship interventions, we retrospectively examined pediatric utilization rates for 48 antimicrobials from 2007 to 2010 as well as appropriateness of vancomycin and cefepime use in 2010.

PATIENTS AND SETTING

All children hospitalized between 2007 and 2010 at the Mayo Clinic Children's Hospital, a 120-bed facility within a larger adult hospital in Rochester, Minnesota.

METHODS

We calculated antimicrobial utilization rates in days of therapy per 1,000 patient-days. Details of vancomycin and cefepime use in 2010 were abstracted by chart review. Two pediatric infectious disease physicians independently assessed appropriateness of antibiotic use.

RESULTS

From 2007 to 2010, 9,880 of 17,242 (57%) hospitalized children received 1 or more antimicrobials. Antimicrobials (days of therapy per 1,000 patient-days) used most frequently in 2010 were cefazolin (97.8), vancomycin (97.1), fluconazole (76.4), piperacillin-tazobactam (70.7), and cefepime (67.6). Utilization rates increased significantly from 2007 to 2010 for 10 antimicrobials, including vancomycin, fluconazole, piperacillin-tazobactam, cefepime, trimethoprim-sulfamethoxazole, caspofungin, and cefotaxime. In 2010, inappropriate use of vancomycin and cefepime was greater in the pediatric intensive care unit than ward (vancomycin: 17.8% vs 6.4%, P = .001; cefepime: 9.2% vs 3.9%, P = .142) and on surgical versus medical services (vancomycin: 20.5% vs 8.0%, P = .001; cefepime: 19.4% vs 3.4%, P ≤ .001). The most common reason for inappropriate antibiotic use was failure to discontinue or de-escalate therapy.

CONCLUSIONS

In our children's hospital, use of 10 antimicrobials increased during the study period. Inappropriate use of vancomycin and cefepime was greatest on the critical care and surgical services, largely as a result of failure to de-escalate therapy, suggesting targets for future antimicrobial stewardship interventions.

Trends in hospitalization for community-associated methicillin-resistant Staphylococcus aureus in New York City, 1997-2006: data from New York State's Statewide Planning and Research Cooperative System

OBJECTIVE

To describe trends in hospitalizations with community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection in New York City over 10 years and to explore the demographics and comorbidities of patients hospitalized with CA-MRSA infections.

DESIGN

Retrospective analysis of hospital discharges from New York State's Statewide Planning and Research Cooperative System database from 1997 to 2006.

PATIENTS

All patients greater than 1 year of age admitted to New York hospitals with diagnosis codes indicating MRSA who met the criteria for CA-MRSA on the basis of admission information and comorbidities.

METHODS

We determined hospitalization rates and compared demographics and comorbidities of patients hospitalized with CA-MRSA versus those hospitalized with all other non-MRSA diagnoses by multivariable logistic regression.

RESULTS

Of 18,226 hospitalizations with an MRSA diagnosis over 10 years, 3,579 (20%) were classified as community-associated. The CA-MRSA hospitalization rate increased from 1.47 to 10.65 per 100,000 people overall from 1997 to 2006. Relative to non-MRSA hospitalizations, men, children, Bronx and Manhattan residents, the homeless, patients with human immunodeficiency virus (HIV) infection, and persons with diabetes had higher adjusted odds of CA-MRSA hospitalization.

CONCLUSIONS

The CA-MRSA hospitalization rate appeared to increase between 1997 and 2006 in New York City, with residents of the Bronx and Manhattan, men, and persons with HIV infection or diabetes at increased odds of hospitalization with CA-MRSA. Further studies are needed to explore how changes in MRSA incidence, access to care, and other factors may have impacted these rates.

Impact of a hospitalwide increase in empiric pediatric vancomycin dosing on initial trough concentrations

STUDY OBJECTIVE

To evaluate the impact of a hospitalwide increase in the recommended vancomycin starting dose from 45 to 60 mg/kg/day on initial vancomycin trough concentrations in children suspected of having an invasive methicillin-resistant Staphylococcus aureus (MRSA) infection.

DESIGN

Retrospective medical record review.

SETTING

Dedicated children's hospital located in a tertiary care, academic medical center.

PATIENTS

A total of 182 children aged 1 month-12 years with normal renal function who had suspected MRSA infections treated with vancomycin during two different starting dose recommendation periods: 45 mg/kg/day divided every 8 hours during July 2006-June 2007 (low-dose group [88 children]) and 60 mg/kg/day divided every 6 hours during July 2008-June 2009 (high-dose group [94 children]).

MEASUREMENT AND MAIN RESULTS

Data on patient demographics, vancomycin doses, and initial vancomycin trough concentrations were collected. No significant demographic differences were noted between patients in the low-dose and high-dose groups. The mean ± SD initial vancomycin trough level increased from 7 ± 5 μg/ml in the low-dose group to 9 ± 5 μg/ml in the high-dose group (p<0.001). The percentage of patients with an initial trough level less than 5 μg/ml declined from 38% (33/88 children) in the low-dose group to 17% (16/94 children) in the high-dose group (p<0.001), whereas the percentage of patients with an initial trough concentration in the potentially adverse range (> 20 μg/ml) did not change between the two groups (2% vs 2%, p=0.9). Less than 14% (13/94 children) achieved a trough level in the range of 15-20 μg/ml in the high-dose group.

CONCLUSION

An increase in the recommended vancomycin starting dose to 60 mg/kg/day decreased the likelihood of an initial low vancomycin trough level (< 5 μg/ml), with no increase in the proportion of patients with trough levels in a potentially toxic range. The 60-mg/kg/day dose did not consistently achieve a vancomycin trough of 15-20 μg/ml, a goal suggested by some experts for adults. Comparative effectiveness studies are needed to directly evaluate vancomycin dosing regimens and clinical outcomes for children with invasive MRSA infections.

Pathologic fractures in children with acute Staphylococcus aureus osteomyelitis

BACKGROUND

Osteomyelitis is a common pediatric musculoskeletal infection. This infection can weaken the normal bone structure, resulting in the risk of a pathologic fracture. The purpose of this study was to evaluate the risk factors for pathologic fracture in children with Staphylococcus aureus osteomyelitis.

METHODS

Seventeen children who were treated for a pathologic long-bone fracture secondary to Staphylococcus aureus osteomyelitis between January 2001 and January 2009 at a tertiary-care pediatric hospital were identified. These patients were compared with a control group consisting of forty-nine children with Staphylococcus aureus osteomyelitis without a fracture who were matched for age, sex, and methicillin susceptibility. A retrospective review of the clinical records, magnetic resonance imaging (MRI) studies, and microbiologic findings was performed.

RESULTS

Patients who developed a fracture presented with osteomyelitis at a mean age of 8.8 years (range, two to seventeen years). Fifteen of the seventeen patients had methicillin-resistant Staphylococcus aureus (MRSA) isolates, and two had methicillin-susceptible Staphylococcus aureus (MSSA). The mean time from disease onset to fracture was 72.1 days (range, twenty to 150 days). The duration of hospitalization, number of surgical procedures, duration of antibiotic treatment, and total number of complications differed significantly between the two groups. MRI studies at the time of admission demonstrated a significantly greater prevalence of subperiosteal abscess and greater circumferential size of such an abscess in the patients with a fracture. A sharp zone of abnormally diminished enhancement of the marrow was also more common in these patients. The USA300-0114 pulsotype was more commonly associated with an elevated likelihood of fracture.

CONCLUSIONS

Staphylococcus aureus osteomyelitis is a serious infection that may predispose children to pathologic fractures. Protected weight-bearing and activity restriction are recommended in children with Staphylococcus aureus osteomyelitis who have the risk factors demonstrated in this study.

High rates of perinatal group B Streptococcus clindamycin and erythromycin resistance in an upstate New York hospital

The objective of this study was to evaluate the rates of clindamycin and erythromycin resistance among group B Streptococcus (GBS)-positive isolates cultured from pregnant women in an upstate New York community hospital. All GBS-positive perinatal rectovaginal cultures obtained from January 2010 through October 2011 were tested for resistance to erythromycin and clindamycin. Among the 688 GBS-positive cultures, clindamycin resistance was found in 38.4% and erythromycin resistance was found in 50.7%. Rates of GBS resistance to clindamycin and erythromycin are much higher than reported in earlier U.S. studies, suggesting both increasing resistance and regional variation in resistance. These findings lend strong support to the CDC and American College of Obstetricians and Gynecologists (ACOG) recommendations that clindamycin use for intrapartum antibiotic prophylaxis be restricted to penicillin-allergic women at high risk of anaphylaxis and that GBS isolates be tested for antibiotic resistance prior to the use of clindamycin in these women.

Common childhood bacterial infections

Children with infectious diseases are commonly encountered in primary care settings. Identification of the subset of patients with bacterial infections is key in guiding the best possible management. Clinicians frequently care for children with infections of the upper respiratory tract, including acute otitis media, otitis externa, sinusitis, and pharyngitis. Conjunctivitis is not an uncommon reason for office visits. Bacterial pneumonia, urinary tract infections, and gastroenteritis are regularly seen. Over the last decade, a growing number of children have had infections of the skin and soft tissue, driven by the increased prevalence of infections caused by methicillin-resistant Staphylococcus aureus. The following review addresses the epidemiology and risk factors for specific infections and examines the clinical presentation and selection of appropriate diagnostic methods in such conditions. Methods to prevent these bacterial infections and recommendations for follow-up are suggested. Management of these infections requires that antimicrobial agents be used in a judicious manner in the outpatient setting. Such antibiotic therapy is recommended using both available clinical evidence and review of disease-specific treatment guidelines.

Emerging dilemmas with methicillin-resistant Staphylococcus aureus infections in children

PURPOSE OF REVIEW

There has been an increase in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections in recent years. This article reviews the literature on three manifestations of MRSA infections in the head and neck of children: sinonasal infections, otologic infections, and neck abscesses.

RECENT FINDINGS

Historically nosocomial in origin, MRSA infections more recently are found to occur in otherwise healthy patients with no obvious risk factors. This community-acquired MRSA is known to be responsible for cutaneous abscesses in various regions of the body. Nasal carriage in healthy children is thought to account for increasing incidence of infections involving the respiratory tract as well as deep-space neck infections. Although these community-acquired strains of MRSA often retain susceptibility to nonbeta lactam antibiotics, there are reports of clindamycin resistance.

SUMMARY

There is an increase in incidence of MRSA among infections involving the head and neck in children. Vigilant monitoring of antibiotic susceptibilities is warranted as well as judicious use of culture-directed antibiotic agents in their treatment. Topical therapy may play an important role in treatment of infections involving the sinonasal tract and ear.