Recurrent community-associated Staphylococcus aureus infections in children presenting to Texas Children's Hospital in Houston, Texas

Management and Prevention of Staphylococcus aureus Infections in Children

Staphylococcus aureus is a common skin commensal with the potential to cause severe infections resulting in significant morbidity and mortality. Up to 30% of individuals are colonized with S aureus, though infection typically does not occur without skin barrier disruption. Infection management includes promptly addressing the source of infection, including sites of metastatic infection, and initiation of effective antibiotics, which should be selected based on local antibiotic susceptibility patterns. Given that S aureus colonization is a risk factor for infection, preventive strategies are aimed at optimizing hygiene measures and decolonization regimens for outpatients and critically ill children with prolonged hospitalizations.

A Longitudinal Study of Assisted Infant Toilet Training During the First Year of Life

OBJECTIVE

Previous retrospective studies have examined elimination signals, stool toileting refusal, and completion age in Assisted Infant Toilet Training (AITT). The aim of this longitudinal cohort study was to describe the practice of AITT and caregiver satisfaction in a primarily Western setting during the first year of life.

METHODS

Families who started AITT before 4 months of age were recruited. Standardized interviews of caregivers were conducted at 1- to 2-month intervals. To identify trends over time, data were fitted to a linear mixed-effect model. Data were analyzed according to five 2-month blocks, starting at 3 to 4 months.

RESULTS

Of 85 participating families, 87 children started AITT at a mean age of 2.5 months. At all age intervals, 88% to 94% of caregivers could identify elimination signals. Toileting attempts decreased from 10/day at 3 to 4 months to 7/day at 11 to 12 months (p < 0.001). Many families (45%-53%) practiced AITT on a part-time basis. Daytime dryness was noted in 12% to 14% of infants throughout the first year. Although more than 63% of families used cloth or disposable diapers throughout this study, use of trainers and underwear increased significantly by 2- to 3-fold (p < 0.01 for both). Caregiver satisfaction was high overall. Although negatively associated with potty refusal, it was positively associated with daytime and nighttime dryness, perceived elimination signals, and a better understanding of their infant's needs (p < 0.001 for all).

CONCLUSION

This study demonstrates that AITT is a worthy viable alternative to the use of diapers even in Western settings. Better understanding of AITT provides a new perspective to properly meet infants' basic needs.

Staphylococcus aureus Skin and Soft Tissue Infection Recurrence Rates in Outpatients: A Retrospective Database Study at 3 US Medical Centers

Background

Staphylococcusaureus skin and soft tissue infections (SA-SSTIs) are common in healthcare and community settings, and recurrences occur at variable frequency, even after successful initial treatment. Knowing the exact burden and timing of recurrent disease is critical to planning and evaluating interventions to prevent recurrent SSTIs.

Methods

In this retrospective study, SSTI cases in patients aged ≥18 years at 3 US medical centers (Columbia, Chicago, Vanderbilt) between 2006 and 2016 were analyzed according to a biennial cohort design. Index SSTIs (with or without key comorbidities), either microbiologically confirmed to be SA-SSTI or not microbiologically tested (NMT-SSTI), were recorded within 1 calendar year and followed up for 12 months for recurrent infections. The number of index cases, proportion of index cases with ≥1 recurrence(s), time to first recurrence, and number of recurrences were collected for both SA-SSTI and NMT-SSTI events.

Results

In the most recent cohorts, 4755 SSTI cases were reported at Columbia, 2873 at Chicago, and 6433 at Vanderbilt. Of these, 452, 153, and 354 cases were confirmed to be due to S. aureus. Most cases were reported in patients without key comorbidities. Across centers, 16.4%–19.0% (SA-SSTI) and 11.0%–19.2% (NMT-SSTI) of index cases had ≥1 recurrence(s). In patients without key comorbidities, more than 60% of index SSTIs with recurrences had only 1 recurrence, half of which occurred in the first 3 months following primary infection.

Conclusions

SA-SSTI recurrences are common among healthy adults and occur in at least 1 in 6 individuals during the 1 year following the primary event.

Prevention Strategies for Recurrent Community-Associated Staphylococcus aureus Skin and Soft Tissue Infections

PURPOSE OF REVIEW

Staphylococcus aureus skin and soft tissue infections (SSTI) are a major source of morbidity. More than half of patients experiencing SSTI will have at least one recurrent infection. These infections frequently cluster in households. Given the burden these infections pose to patients and healthcare, prevention strategies are of major clinical importance and represent an active area of research. Bacterial colonization is frequently an early and critical step in the pathogenesis of infection. As such, strategies to prevent reinfection have aimed to decrease staphylococcal colonization of the skin and mucus membranes, a process referred to as decolonization.

RECENT FINDINGS

Treatment of acute SSTI with incision and drainage and systemic antibiotics is the mainstay of therapy for healing of the acute infection. Systemic antibiotics also provide benefit through reduced incidence of recurrent SSTI. Education for patients and families regarding optimization of personal and household hygiene measures, and avoidance of sharing personal hygiene items, is an essential component in prevention efforts. For patients experiencing recurrent SSTI, or in households in which multiple members have experienced SSTI, decolonization should be recommended for all household members. A recommended decolonization regimen includes application of intranasal mupirocin and antiseptic body washes with chlorhexidine or dilute bleach water baths. For patients who continue to experience recurrent SSTI, periodic decolonization should be considered. Personal decolonization with topical antimicrobials and antiseptics reduces the incidence of recurrent S. aureus SSTI. Future avenues for investigation include strategies for household environmental decontamination as well as manipulation of the host microbiota.

Diaper Use Increases the Risk of Buttock and Perineal Abscesses

OBJECTIVES

Over the last decade, there has been a notable increase in the incidence of abscesses. Children in the diaper-wearing age group are disproportionately affected, and most of these abscesses occur in the buttock and perineal region. Using case-control methodology, we sought to determine if diaper use itself is an independent risk factor for abscess formation.

METHODS

Cases were patients, at least 2 years of age but less than 4 years, who presented to the emergency department with a complaint of a buttock or perineal abscess. Age-matched controls presented to the emergency department for unrelated reasons. Caregivers of subjects responded to a survey regarding diaper use (toilet trained, for sleep only, or all day), type and brand of diaper, and diaper hygiene-related factors.

RESULTS

We enrolled 465 patients (93 cases, 372 controls). Fully toilet trained children were less likely to have buttock and perineal abscess than their sleep-only and all-day diaper-wearing peers. Limiting diaper use to naptime and overnights (sleep only) did not confer protection against abscesses. Diaper hygiene-related factors did not affect the risk of abscess formation. Female sex was also identified as a strong risk factor for buttock and perineal abscess formation.

CONCLUSIONS

Diaper use is a potentially modifiable risk factor for buttock and perineal abscess formation in young children.

Impact of Systemic Antibiotics on Staphylococcus aureus Colonization and Recurrent Skin Infection

Background

Staphylococcus aureus colonization poses risk for subsequent skin and soft tissue infection (SSTI). We hypothesized that including systemic antibiotics in the management of S. aureus SSTI, in conjunction with incision and drainage, would reduce S. aureus colonization and incidence of recurrent infection.

Methods

We prospectively evaluated 383 children with S. aureus SSTI requiring incision and drainage and S. aureus colonization in the anterior nares, axillae, or inguinal folds at baseline screening. Systemic antibiotic prescribing at the point of care was recorded. Repeat colonization sampling was performed within 3 months (median, 38 days; interquartile range, 22-50 days) in 357 participants. Incidence of recurrent infection was ascertained for up to 1 year.

Results

Participants prescribed guideline-recommended empiric antibiotics for purulent SSTI were less likely to remain colonized at follow-up sampling (adjusted hazard ratio [aHR], 0.49; 95% confidence interval [CI], .30-.79) and less likely to have recurrent SSTI (aHR, 0.57; 95% CI, .34-.94) than those not receiving guideline-recommended empiric antibiotics for their SSTI. Additionally, participants remaining colonized at repeat sampling were more likely to report a recurrent infection over 12 months (aHR, 2.37; 95% CI, 1.69-3.31). Clindamycin was more effective than trimethoprim-sulfamethoxazole (TMP-SMX) in eradicating S. aureus colonization (44% vs 57% remained colonized, P = .03) and preventing recurrent SSTI (31% vs 47% experienced recurrence, P = .008).

Conclusions

Systemic antibiotics, as part of acute SSTI management, impact S. aureus colonization, contributing to a decreased incidence of recurrent SSTI. The mechanism by which clindamycin differentially affects colonization and recurrent SSTI compared to TMP-SMX warrants further study.

Repeat gram-negative hospital-acquired infections and antibiotic susceptibility: A systematic review

Repeat HAIs among frequently hospitalized patients may be contributing to the high rates of antibiotic resistance seen in gram-negative bacteria (GNB) in hospital settings. This systematic review examines the state of the literature assessing the association between repeat GNB HAIs and changes in antibiotic susceptibility patterns. A systematic search of English language published literature was conducted to identify studies in peer-reviewed journals from 2000 to 2015. Studies must have assessed drug resistance in repeat GNB infections longitudinally at the patient level. Two researchers independently reviewed search results for papers meeting inclusion criteria and extracted data. Risk of bias was assessed using a modified quality assessment tool based on the Checklist for Measuring Study Quality and the Quality Assessment Checklist for Cases Series. From 3385 articles identified in the search, seven met inclusion criteria. Five reported lower antibiotic susceptibility in repeated infections, one found a change but did not specify in which direction, and one reported no change. All studies were of low to average quality. Despite the dearth of studies examining repeat GNB infections, evidence suggests that repeat infections result in lower antibiotic susceptibility among hospitalized patients. Larger scale studies with strong methodology are warranted.

Staphylococcus aureus in the Intensive Care Unit: Are These Golden Grapes Ripe for a New Approach?

Staphylococcus aureus is the leading cause of infection in the setting of critical illness and injury. This pathogen causes life-threatening infection in otherwise healthy individuals and also complicates the clinical course of patients requiring intensive care as a result of their primary medical or surgical disease processes. S. aureus infection in the intensive care unit (ICU) most commonly manifests as sepsis, ventilator-associated pneumonia, and infection of surgical sites and indwelling medical devices. With the epidemic spread of methicillin-resistant S. aureus, many cases of staphylococcal infection in the ICU are now classified as drug resistant, prompting hospital-based screening for methicillin-resistant S. aureus and implementation of both isolation practices and decolonization strategies in ICU patients. The genetic adaptability of S. aureus, heterogeneity of disease presentation, clinical course, and outcome between individual S. aureus-infected ICU patients remains enigmatic, suggesting a need to define disease classification subtypes that inform disease progression and therapy. We propose that S. aureus infection in the ICU now presents a unique opportunity for individualized risk stratification coupled with the investigation of novel approaches to mitigate disease. Given our increasing knowledge of the molecular pathogenesis of S. aureus disease, we suggest that the application of molecular pathological epidemiology to S. aureus infection can usher in a new era of highly focused personalized therapy that may be particularly beneficial in the setting of critical illness and injury.

A prospective observational cohort study in primary care practices to identify factors associated with treatment failure in Staphylococcus aureus skin and soft tissue infections

Background

The incidence of outpatient visits for skin and soft tissue infections (SSTIs) has substantially increased over the last decade. The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has made the management of S. aureus SSTIs complex and challenging. The objective of this study was to identify risk factors contributing to treatment failures associated with community-associated S. aureus skin and soft tissue infections SSTIs.

Methods

This was a prospective, observational study among 14 primary care clinics within the South Texas Ambulatory Research Network. The primary outcome was treatment failure within 90 days of the initial visit. Univariate associations between the explanatory variables and treatment failure were examined. A generalized linear mixed-effect model was developed to identify independent risk factors associated with treatment failure.

Results

Overall, 21% (22/106) patients with S. aureus SSTIs experienced treatment failure. The occurrence of treatment failure was similar among patients with methicillin-resistant S. aureus and those with methicillin-susceptible S. aureus SSTIs (19 vs. 24%; p = 0.70). Independent predictors of treatment failure among cases with S. aureus SSTIs was a duration of infection of ≥7 days prior to initial visit [aOR, 6.02 (95% CI 1.74–19.61)] and a lesion diameter size ≥5 cm [5.25 (1.58–17.20)].

Conclusions

Predictors for treatment failure included a duration of infection for ≥7 days prior to the initial visit and a wound diameter of ≥5 cm. A heightened awareness of these risk factors could help direct targeted interventions in high-risk populations.

Factors influencing drainage setting and cost for cutaneous abscesses among pediatric patients

OBJECTIVE

To evaluate the clinical and microbiological factors associated with skin and soft tissue infections drained in the emergency department (ED) vs operative drainage (OD) in a tertiary care children's hospital.

METHODS

This was a cross-sectional study among children aged 2 months to 17 years who required incision and drainage (I&D). Demographic information, signs and symptoms, abscess size and location, and wound culture/susceptibility were recorded. Patient-specific charges were collected from the billing database. Multivariate regression analysis was used to determine factors determining setting for I&D and the effect of abscess drainage location on cost.

RESULTS

Of 335 abscesses, 241 (71.9%) were drained in the ED. OD for abscesses was favored in children with prior history of abscess (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.36-7.44; P = .01) and labial location (OR, 37.81; 95% CI, 8.12-176.03; P < .001). For every 1-cm increase in size, there was approximately a 26% increase in the odds of having OD (OR, 1.26; 95% CI, 1.11-1.44, P < .001). Methicillin-resistant Staphylococcus aureus was identified in 72% of the 300 abscesses cultured and 12.3% were clindamycin resistant. OD was more expensive than I&D in the ED. Per abscess that underwent I&D, OD is $3804.29 more expensive than I&D in the ED while controlling for length of stay.

DISCUSSION

Clinical factors associated with OD rather than I&D in the ED included history of abscess, increased abscess length, and labial location. Microbiological factors did not differ based on I&D setting. For smaller, nonlabial abscesses, ED drainage may result in significant cost savings.

Prevention of Recurrent Staphylococcal Skin Infections

Staphylococcus aureus infections pose a significant health burden. The emergence of community-associated methicillin-resistant S aureus has resulted in an epidemic of skin and soft tissue infections (SSTI), and many patients experience recurrent SSTI. As S aureus colonization is associated with subsequent infection, decolonization is recommended for patients with recurrent SSTI or in settings of ongoing transmission. S aureus infections often cluster within households, and asymptomatic carriers serve as reservoirs for transmission; therefore, a household approach to decolonization is more effective than measures performed by individuals alone. Novel strategies for the prevention of recurrent SSTI are needed.

Host factors that contribute to recurrent staphylococcal skin infection

PURPOSE OF REVIEW

Staphylococcus aureus is the most common cause of skin and soft tissue infections (SSTI) in the United States and elsewhere. Recurrent infections occur frequently in patients with S. aureus SSTI, underscoring the need to better understand the nature of protective immunity against these infections. Here, we review recent findings concerning the host factors that predispose to S. aureus SSTI.

RECENT FINDINGS

Recurrent infections occur in nearly half of all patients with S. aureus SSTI. Epidemiologic and environmental factors, such as exposure to healthcare, age, and household contacts with S. aureus SSTI, and contaminated household fomites are associated with recurrence. The majority of the population has evidence of antistaphylococcal antibodies, but whether these are protective remains enigmatic. In contrast, recent clinical and experimental findings clearly highlight the critical roles of innate and T cell-mediated immunity in defense against these infections. S. aureus interferes with innate and adaptive immunity by a number of recently elucidated mechanisms.

SUMMARY

Recurrent S. aureus SSTIs are common, suggesting incomplete or absent protective immunity among these patients. Our understanding of protective immunity against recurrent infections is incomplete, and further basic and translational investigation is urgently needed to design strategies to prevent and treat these infections.

Staphylococcus aureus-Associated Skin and Soft Tissue Infections: Anatomical Localization, Epidemiology, Therapy and Potential Prophylaxis

Skin and soft tissue infections (SSTIs) are among the most common infections worldwide. They range in severity from minor, self-limiting, superficial infections to life-threatening diseases requiring all the resources of modern medicine. Community (CA) and healthcare (HA) acquired SSTIs are most commonly caused by Staphylococcus aureus . They have variable presentations ranging from impetigo and folliculitis to surgical site infections (SSIs). Superficial SSTIs may lead to even more invasive infections such as bacteraemia and osteomyelitis. Here we describe the anatomical localization of the different SSTI associated with S. aureus, the virulence factors known to play a role in these infections, and their current epidemiology. Current prevention and treatment strategies are also discussed. Global epidemiological data show increasing incidence and severity of SSTIs in association with methicillin-resistant S. aureus strains (MRSA). CA-SSTIs are usually less morbid compared to other invasive infections caused by S. aureus, but they have become the most prevalent, requiring a great number of medical interventions, extensive antibiotic use, and therefore a high cost burden. Recurrence of SSTIs is common after initial successful treatment, and decolonization strategies have not been effective in reducing recurrence. Furthermore, decolonization approaches may be contributing to the selection and maintenance of multi-drug resistant strains. Clinical studies from the early 1900s and novel autovaccination approaches suggest an alternative strategy with potential effectiveness: using vaccines to control S. aureus cutaneous infections.

Discriminatory Indices of Typing Methods for Epidemiologic Analysis of Contemporary Staphylococcus aureus Strains

Historically, a number of typing methods have been evaluated for Staphylococcus aureus strain characterization. The emergence of contemporary strains of community-associated S. aureus, and the ensuing epidemic with a predominant strain type (USA300), necessitates re-evaluation of the discriminatory power of these typing methods for discerning molecular epidemiology and transmission dynamics, essential to investigations of hospital and community outbreaks. We compared the discriminatory index of 5 typing methods for contemporary S. aureus strain characterization. Children presenting to St. Louis Children's Hospital and community pediatric practices in St. Louis, Missouri (MO), with community-associated S. aureus infections were enrolled. Repetitive sequence-based PCR (repPCR), pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), staphylococcal protein A (spa), and staphylococcal cassette chromosome (SCC) mec typing were performed on 200 S. aureus isolates. The discriminatory index of each method was calculated using the standard formula for this metric, where a value of 1 is highly discriminatory and a value of 0 is not discriminatory. Overall, we identified 26 distinct strain types by repPCR, 17 strain types by PFGE, 30 strain types by MLST, 68 strain types by spa typing, and 5 strain types by SCCmec typing. RepPCR had the highest discriminatory index (D) of all methods (D = 0.88), followed by spa typing (D = 0.87), MLST (D = 0.84), PFGE (D = 0.76), and SCCmec typing (D = 0.60). The method with the highest D among MRSA isolates was repPCR (D = 0.64) followed by spa typing (D = 0.45) and MLST (D = 0.44). The method with the highest D among MSSA isolates was spa typing (D = 0.98), followed by MLST (D = 0.93), repPCR (D = 0.92), and PFGE (D = 0.89). Among isolates designated USA300 by PFGE, repPCR was most discriminatory, with 10 distinct strain types identified (D = 0.63). We identified 45 MRSA isolates which were classified as identical by PFGE, MLST, spa typing, and SCCmec typing (USA300, ST8, t008, SCCmec IV, respectively); within this collection, there were 5 distinct strain types identified by repPCR. The typing methods yielded comparable discriminatory power for S. aureus characterization overall; when discriminating among USA300 isolates, repPCR retained the highest discriminatory power. This property is advantageous for investigations conducted in the era of contemporary S. aureus infections.

Protein A suppresses immune responses during Staphylococcus aureus bloodstream infection in guinea pigs

Staphylococcus aureus infection is not associated with the development of protective immunity, and disease relapses occur frequently. We hypothesize that protein A, a factor that binds immunoglobulin Fcγ and cross-links V(H)3 clan B cell receptors (IgM), is the staphylococcal determinant for host immune suppression. To test this, vertebrate IgM was examined for protein A cross-linking. High V(H)3 binding activity occurred with human and guinea immunoglobulin, whereas mouse and rabbit immunoglobulins displayed little and no binding, respectively. Establishing a guinea pig model of S. aureus bloodstream infection, we show that protein A functions as a virulence determinant and suppresses host B cell responses. Immunization with SpA(KKAA), which cannot bind immunoglobulin, elicits neutralizing antibodies that enable guinea pigs to develop protective immunity.

IMPORTANCE

Staphylococcus aureus is the leading cause of soft tissue and bloodstream infections; however, a vaccine with clinical efficacy is not available. Using mice to model staphylococcal infection, earlier work identified protective antigens; however, corresponding human clinical trials did not reach their endpoints. We show that B cell receptor (IgM) cross-linking by protein A is an important immune evasion strategy of S. aureus that can be monitored in a guinea pig model of bloodstream infection. Further, immunization with nontoxigenic protein A enables infected guinea pigs to elicit antibody responses that are protective against S. aureus. Thus, the guinea pig model may support preclinical development of staphylococcal vaccines.

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.

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.