Staphylococcus aureus Bacteremia in Children Aged 5-18 Years-Risk Factors in the New Millennium

The molecular epidemiology and clinical implication of methicillin-resistant Staphylococcus aureus (MRSA) sequence types in pediatric bacteremia: a restrospective observational study, 2016-2021

BACKGROUND

While there is a high burden of methicillin-resistant Staphylococcus aureus (MRSA) infections among pediatric patients, studies on the molecular epidemiology of MRSA infections in Korean children since the 2010s are lacking. This study aimed to investigate the molecular genotypes and clinical characteristics of MRSA isolates from children with MRSA bacteremia at Asan Medical Center Children's Hospital from 2016 to 2021.

METHODS

Clinical data were retrospectively reviewed, and the molecular types of MRSA were determined using multilocus sequence typing (MLST) and Staphylococcal cassette chromosome mec (SCCmec) typing.

RESULTS

The overall methicillin resistance rate of S. aureus bacteremia was 44.8% (77/172); 49.5% in the period 2016-2018 (period 1) and 37.3% in the period 2019-2021 (period 2) (P = 0.116). Community-acquired infections accounted for only 3.9% of cases. The predominant ST group was ST72 group (67.6%), followed by ST5 group (18.9%) and ST1 group (5.4%). The proportion of ST5 was significantly lower in period 2 compared to period 1 (P = 0.02). Compared to the ST5 and ST1 groups, the ST72 group exhibited lower overall antibiotic resistance and multidrug-resistant (MDR) rates (12.0% [6/50] in ST72 group vs. 100.0% [14/14] in ST5 group vs. 50.0% [2/4] in ST1 group; P < 0.001). In the multivariate analysis, the ST1 group was an independent risk factor for 30-day all-cause mortality (aOR, 44.12; 95% CI, 3.46-562.19).

CONCLUSION

The ST72-MRSA strain remained the most frequently isolated genotype in Korean children, while the ST1 group emerged as an independent risk factor for 30-day all-cause mortality in pediatric MRSA bacteremia. Ongoing efforts to uncover the evolving epidemiology of MRSA are essential for developing effective strategies for prevention and treatment.

Phenotypic and Endotypic Determinants of Atopic Dermatitis Severity From the Atopic Dermatitis Research Network (ADRN) Registry

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a highly variable clinical phenotype.

OBJECTIVE

This study aimed to identify historical and clinical features and biomarkers associated with AD severity.

METHODS

A US registry of extensively phenotyped AD participants (aged 0.73-80 years) were enrolled at 9 academic centers. Information on family and personal medical history, examination, skin swabs (culture), and serum biomarkers was collected to evaluate their association with AD severity.

RESULTS

Participants with AD (N = 2862) whose disease was categorized as mild (11.6%), moderate (58.0%), or severe (30.4%) based on Rajka-Langeland scoring were enrolled. The trend test, when adjusting for gender, race, and age, demonstrated that severity was strongly (P ≤ .04) associated with a personal/family history of allergic disorders, history of alopecia, exposure to passive smoke, ocular herpes infection, skin bacterial and viral infections, and history of arrhythmia. Features observed more frequently (P ≤ .002), as a function of severity, included skin infections (impetigo, human papillomavirus, and molluscum contagiosum virus), Staphylococcus aureus colonization, excoriations, hyperlinear palms, ichthyosis, blepharitis, conjunctivitis, ectropion, and wheezing. Serum IgE, allergen and food (≤6 years) Phadiatop, and eosinophilia were strongly linked to severity (P < .001).

CONCLUSIONS

In a diverse US AD population, severity was associated with a history of atopic disorders, skin and extracutaneous bacterial and viral infections (by history and physical examination), higher IgE, eosinophilia and allergen sensitization, atopic skin manifestations (ie, excoriation, hyperlinear palms, and ichthyosis), and atopic ocular features (ie, blepharitis, conjunctivitis, and ectropion) as well as asthma findings (ie, wheezing). Data from our prospective registry significantly advance our understanding of AD phenotypes and endotypes, which is critical to achieve optimal management.

Factors linked to Staphylococcus aureus healthcare-associated infections among pediatric intensive care unit colonized patients

BACKGROUND

Staphylococcus aureus (SA) is one of the main pathogens responsible for healthcare-associated infection (HCAI) in pediatrics. The aim of this study was to describe the prevalence of SA-HCAI among colonized patients and the factors associated with it in the pediatric intensive care unit (PICU).

METHODS

We designed a 6-year retrospective cohort study of a PICU in a French university children's hospital including all children admitted to the PICU from January 1, 2011, to December 31, 2016, who had SA colonization on PICU admission. For each patient, the past medical history and the hospitalization data were collected. HCAIs related to SA were verified according to the criteria of the United States Centers for Disease Control and Prevention.

RESULTS

Among all patients colonized with SA (n = 1381, 26%), 105 (8%) had methicillin-resistant SA carriage and 41 (3%) developed an HCAI caused by SA. The main HCAIs were ventilator-associated pneumonia (51%) and central line-associated bloodstream infections (27%). Patients developing HCAI caused by SA had a significantly longer length of hospital stay and a higher mortality rate than the rest of the population. Using a multivariate logistic regression model, the presence of mechanical ventilation, the implementation of a surgical procedure during the PICU stay, and the onset of at least one episode of anemia during the PICU stay were significantly associated with the occurrence of HCAI due to SA.

CONCLUSION

HCAIs linked to SA carriage are rare but severe. Mechanical ventilation, surgery during the PICU stay, and anemia are factors associated with SA-HCAI.

Risk factors for cardiac implantable electronic device infections: a nationwide Danish study

AIMS

Cardiac implantable electronic device (CIED) infection is a severe complication to modern management of cardiac arrhythmias. The CIED type and the type of surgery are recognized as risk factors for CIED infections, but knowledge of patient-related risk factors is scarce. This study aimed to identify lifelong patient-related risk factors for CIED infections.

METHODS AND RESULTS

Consecutive Danish patients undergoing a CIED implantation or reoperation between January 1996 and April 2018 were included. The cohort consisted of 84 429 patients undergoing 108 494 CIED surgeries with a combined follow-up of 458 257 CIED-years. A total of 1556 CIED explantations were classified as either pocket (n = 1022) or systemic CIED infection (n = 534). Data were cross-linked with records from the Danish National Patient Registry and the Danish National Prescription Registry. Using multiple-record and multiple-event per subject proportional hazard analysis, specific patient-related risk factors were identified but with several variations amongst the subtypes of CIED infection. CIED reoperations were associated with the highest risk of pocket CIED infection but also CIED type, young age, and prior valvular surgery [hazard ratio (HR): 1.62, 95% confidence interval (CI): 1.29-2.04]. Severe renal insufficiency/dialysis (HR: 2.40, 95% CI: 1.65-3.49), dermatitis (HR: 2.80, 95% CI: 1.92-4.05), and prior valvular surgery (HR: 2.09, 95% CI: 1.59-2.75) were associated with the highest risk of systemic CIED infections. Congestive heart failure, ischaemic heart disease, malignancy, chronic obstructive pulmonary disease, and temporary pacing were not significant at multivariate analysis.

CONCLUSION

Specific comorbidities and surgical procedures were associated with a higher risk of CIED infections but with variations amongst pocket and systemic CIED infection. Pocket CIED infections were associated with CIED reoperations, young age and more complex type of CIED, whereas systemic CIED infections were associated with risk factors predisposing to bacteraemia.

Staphylococcus aureus infections after elective pediatric surgeries

Objective:

To determine the 180-day cumulative incidence of culture-confirmed Staphylococcus aureus infections after elective pediatric surgeries.

Design:

Retrospective cohort study utilizing the Premier Healthcare database (PHD).

Setting:

Inpatient and hospital-based outpatient elective surgical discharges.

Patients:

Pediatric patients <18 years who underwent surgery during elective admissions between July 1, 2010, and June 30, 2015, at any of 181 PHD hospitals reporting microbiology results.

Methods:

In total, 74 surgical categories were defined using ICD-9-CM and CPT procedure codes. Microbiology results and ICD-9-CM diagnosis codes defined S. aureus infection types: bloodstream infection (BSI), surgical site infection (SSI), and other types (urinary tract, respiratory, and all other). Cumulative postsurgical infection incidence was calculated as the number of infections divided by the number of discharges with qualifying elective surgeries.

Results:

Among 11,874 inpatient surgical discharges, 180-day S. aureus infection incidence was 1.79% overall (1.00% SSI, 0.35% BSI, 0.45% other). Incidence was highest among children <2 years of age (2.76%) and lowest for those 10–17 years (1.49%). Among 50,698 outpatient surgical discharges, incidence was 0.36% overall (0.23% SSI, 0.05% BSI, 0.08% others); it was highest among children <2 years of age (0.57%) and lowest for those aged 10–17 years (0.30%). MRSA incidence was significantly higher after inpatient surgeries (0.68%) than after outpatient surgeries (0.14%; P < .0001). Overall, the median days to S. aureus infection was longer after outpatient surgery than after inpatient surgery (39 vs. 31 days; P = .0116).

Conclusions:

These findings illustrate the burden of postoperative S. aureus infections in the pediatric population, particularly among young children. These results underscore the need for continued infection prevention efforts and longer-term surveillance after surgery.

Development of an Iliacus Muscle Abscess after School Exercise in a 17-Year-Old Female Student

Primary psoas abscess is due largely to hematogenous or lymphatic spread under immunocompromised conditions, whereas secondary psoas abscess is due largely to direct spread from adjacent infected structures. Trauma or hematoma within the muscle may predispose to the development of a primary abscess, especially if infection is present prior to injury, despite the absence of previous signs or symptoms of infection. This report describes a 17-year-old female high school student who developed an abscess within her iliacus muscle due to methicillin-susceptible <i>Staphylococcus aureus</i> after running 3 km on a hill as a school exercise. She was positive for antinuclear antibody and had had atopic dermatitis, suggesting that these factors, as well as exercise-related minor trauma or hematoma within the muscle, may have predisposed to abscess formation. She was treated with appropriate antibiotics and surgical drainage, resulting in recovery after 4 weeks.

Impact of a Best Practice Advisory for Pediatric Patients With Staphylococcus aureus Bacteremia

BACKGROUND

Infectious diseases (ID) consultation and optimal antibiotic therapy improve outcomes in Staphylococcus aureus bacteremia (SAB). Data on strategies to improve adherence to these practices in children are limited.

METHODS

This was a quasi-experimental study evaluating the impact of an electronic medical record (EMR)-based best practice advisory (BPA) for SAB, recommending ID consult and optimal antibiotic therapy based on rapid mecA gene detection. Inpatients < 21 years old with SAB before (January 2015-July 2017) and after (August 2017-December 2018) BPA implementation were included. Primary outcome was receipt of ID consult. Secondary outcomes included receipt of optimal therapy, time to ID consult and optimal therapy, recurrent SAB, and 30-day all-cause mortality. ID consultation rates pre- and postimplementation were compared using interrupted time series (ITS) analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) for time to optimal therapy were calculated using Cox regression.

RESULTS

We included 99 SAB episodes (70 preintervention, 29 postintervention). Preintervention, 48 (68.6%) patients received an ID consult compared to 27 (93.1%) postintervention, but this was not statistically significant on ITS analysis due to a preexisting trend of increasing consultation. Median hours to optimal therapy decreased from 26.1 to 5.5 (P = .03), most notably in patients with methicillin-sensitive S. aureus (MSSA) (42.2 to 10.8; P < .01). On Cox regression, BPA implementation was associated with faster time to optimal therapy (HR, 3.22 [95% CI, 1.04-10.01]).

CONCLUSIONS

Implementation of an EMR-based BPA for SAB resulted in faster time to optimal antibiotic therapy, particularly for patients with MSSA. ID consultation increased throughout the study period and was not significantly impacted by the BPA.

Role of Antimicrobial Peptides in Skin Barrier Repair in Individuals with Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that exhibits a complex interplay of skin barrier disruption and immune dysregulation. Patients with AD are susceptible to cutaneous infections that may progress to complications, including staphylococcal septicemia. Although most studies have focused on filaggrin mutations, the physical barrier and antimicrobial barrier also play critical roles in the pathogenesis of AD. Within the physical barrier, the stratum corneum and tight junctions play the most important roles. The tight junction barrier is involved in the pathogenesis of AD, as structural and functional defects in tight junctions not only disrupt the physical barrier but also contribute to immunological impairments. Furthermore, antimicrobial peptides, such as LL-37, human b-defensins, and S100A7, improve tight junction barrier function. Recent studies elucidating the pathogenesis of AD have led to the development of barrier repair therapy for skin barrier defects in patients with this disease. This review analyzes the association between skin barrier disruption in patients with AD and antimicrobial peptides to determine the effect of these peptides on skin barrier repair and to consider employing antimicrobial peptides in barrier repair strategies as an additional approach for AD management.

Assessment of the Antimicrobial Potentiality and Functionality of Lactobacillus plantarum Strains Isolated from the Conventional Inner Mongolian Fermented Cheese Against Foodborne Pathogens

Lactobacillus plantarum are amongst the diversified lactic acid bacteria (LAB) species which are being utilized abundantly in the food industry. Numerous L. plantarum strains have been reported to produce several antimicrobial compounds. Diacetyl, hydrogen peroxide, organic acids, as well as bacteriocins can also be exemplified by a variable spectrum of actions. The current study was intended to conduct the screening and characterization of antimicrobial prospective of L. plantarum from traditional Inner Mongolian fermented hard cheese. Foodborne pathogens, Salmonella typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, and Staphylococcus aureus, were examined by using the Oxford cup technique and the mixed culture inhibition assays. The resulting analyses disclosed that L. plantarum KLDS1.0344 indicated broad antimicrobial spectrum against all selected pathogens as compared to other LAB used in this study. Additionally, the decrement of the pathogen population was observed up to 3.47 logs in mixed culture inhibition assays. L. plantarum KLDS 1.0344 acid production was recorded up to 71.8 ± 3.59 °D in mixed culture while antimicrobial particles released in cell free supernatants demonstrated bacteriocin-like characteristics showing substantial pH stability (2.0–6.0), proteolytic enzyme reduced the antibacterial activity (15.2 ± 0.6 mm–20.4 ± 0.8 mm), heat stability (20 min at 120 °C) against selected pathogens. Moreover, the spectrum range of antimicrobial peptides after the partial purification was decreased as compared to the crude bacteriocin-like compound. The SDS-PAGE analysis showed the molecular weight range of partially purified bacteriocin from 12 to 45 kDa. After analyzing the obtained data from the current experimentation showed that the capability of L. plantarum KLDS 1.0344 to oppose the pathogen growth in vitro relies on the occurrence of organic acids along with bacteriocin-like compounds proving L. plantarum KLDS 1.0344 as a potentially appropriate candidate as an alternative bio-control agent against foodborne pathogens.

Antibiotic choice and methicillin-resistant Staphylococcus aureus rate in children hospitalized for atopic dermatitis

BACKGROUND

Systemic antibiotics are commonly used in hospitalized patients with severe atopic dermatitis (AD) exacerbation. However, the antibiotic prescribing patterns are unclear.

OBJECTIVE

To compare the prescribing patterns of antibiotics for children who were hospitalized for AD exacerbation and infectious complications.

METHODS

Electronic medical records were reviewed for patients younger than 18 years who were hospitalized for AD exacerbation or infectious complications based on International Classification of Diseases, Ninth Revision, Clinical Modification and International Classification of Diseases, Tenth Revision, Clinical Modification codes from 2003 to 2018. The following information was obtained: history, physical examination findings, physician discharge summary, antibiotic treatments, serum tests, and wound cultures. The t test was used to compare clinical and laboratory features.

RESULTS

A total of 174 patients with AD were included. Seventy patients had AD exacerbation and 104 had infectious complications, including cellulitis, abscesses, invasive infections, and eczema herpeticum. The differences between these 2 groups of patients were further verified by length of stay, serum total IgE level, and inflammatory markers (C-reactive protein and erythrocyte sedimentation rate). A total of 56 of 70 patients (80%) with AD exacerbation were treated with a systemic antibiotic. Clindamycin and vancomycin together accounted for 88% of antibiotics on admission for both groups, whereas clindamycin and sulfamethoxazole-trimethoprim were prescribed at similar rates for both groups at discharge. Wound culture results showed that the methicillin-resistant Staphylococcus aureus (MRSA) rate was significantly lower in children with AD exacerbation (22%) vs infectious complications (39%).

CONCLUSION

Children were treated with a high frequency of anti-MRSA antibiotics for inpatient AD exacerbation and infectious complications. However, the rate of MRSA was significantly lower in children with AD exacerbation. Thus, empiric antibiotic choice for infectious complications may not be appropriate for AD exacerbation.