Management and outcome of children with skin and soft tissue abscesses caused by community-acquired methicillin-resistant Staphylococcus aureus

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

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

Emergency department treatment failures for skin infections in the era of community-acquired methicillin-resistant Staphylococcus aureus

BACKGROUND

Despite rapidly increasing incidence of skin and soft tissue infections (SSTIs) presenting to emergency departments (EDs), outcome data for these infections are limited.

METHODS

This is a retrospective cohort study of children with culture-positive SSTI, managed as outpatients from a large pediatric ED in the year 2006. The primary outcome was treatment failure, defined as presence of 1 or more of the following: (1) change in antibiotic owing to poor clinical response, (2) subsequent incision and drainage, or (3) hospitalization. Demographics, isolated pathogens, and therapeutics were also assessed. To accurately capture the outcome of interest, only children who are observed in the hospital-based primary care network were included.

RESULTS

Among 148 eligible subjects, there were 158 SSTIs including 131 abscesses, 19 folliculitis, and 8 cellulitis. Mean age was 9.1 ± 6.2 years, 41.2% were male, and 94.6% were African American. Methicillin-resistant Staphylococcus aureus (MRSA) was isolated in 66%, methicillin-sensitive S. aureus (MSSA) in 21%, and others in 13%. Outcome data were available for 144 subjects (97.2%). Emergency department treatment failure rate was 7.6% (95% confidence interval, 3.3%-12.0%); 10 of 11 failures were abscesses. Only S. aureus produced treatment failure and occurred in 13.3% of MSSA and 6.4% MRSA infections (odds ratio, 1.9; 95% CI, 0.5-7.1). An antibiotic to which the organism was sensitive was prescribed for 9 (81.8%) of 11 treatment failures and did not differ between MRSA and MSSA; appropriate antibiotics were used in 91.5% of treatment successes.

CONCLUSIONS

The rate of ED treatment failure for SSTI is low and is more likely to occur with S. aureus infection, irrespective of methicillin resistance or appropriate antibiotic therapy.

Methicillin-resistant Staphylococcus aureus in diabetic foot infections

Diabetic foot ulcers are often complicated by infection. Among pathogens, Staphylococcus aureus predominates. The prevalence of methicillin-resistant S. aureus (MRSA) in infected foot ulcers is 15-30% and there is an alarming trend for increase in many countries. There are also data that recognize new strains of MRSA that are resistant to vancomycin. The risk for MRSA isolation increases in the presence of osteomyelitis, nasal carriage of MRSA, prior use of antibacterials or hospitalization, larger ulcer size and longer duration of the ulcer. The need for amputation and surgical debridement increases in patients infected with MRSA. Infections of mild or moderate severity caused by community-acquired MRSA can be treated with cotrimoxazole (trimethoprim/sulfamethoxazole), doxycycline or clindamycin when susceptibility results are available, while severe community-acquired or hospital-acquired MRSA infections should be managed with glycopeptides, linezolide or daptomycin. Dalbavancin, tigecycline and ceftobiprole are newer promising antimicrobial agents active against MRSA that may also have a role in the treatment of foot infections if more data on their efficacy and safety become available.

Fusidic acid and clindamycin resistance in community-associated, methicillin-resistant Staphylococcus aureus infections in children of Central Greece

Introduction

In Greece, fusidic acid and clindamycin are commonly used for the empiric therapy of suspected staphylococcal infections.

Methods

The medical records of children examined at the outpatient clinics or admitted to the pediatric wards of the University General Hospital of Larissa, Central Greece, with community-associated staphylococcal infections from January 2003 to December 2009 were reviewed.

Results

Of 309 children (0-14 years old), 21 (6.8%) had invasive infections and 288 (93.2%) skin and soft tissue infections (SSTIs). Thirty-five patients were ≤30 days of age. The proportion of staphylococcal infections caused by a community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolate increased from 51.5% (69 of 134) in 2003-2006 to 63.4% (111 of 175) in 2007-2009 (P = 0.037). Among the CA-MRSA isolates, 88.9% were resistant to fusidic acid, 77.6% to tetracycline, and 21.1% to clindamycin. Clindamycin resistance increased from 0% (2003) to 31.2% (2009) among the CA-MRSA isolates (P = 0.011). Over the 7-year period, an increase in multidrug-resistant CA-MRSA isolates was observed (P = 0.004). One hundred and thirty-one (93.6%) of the 140 tested MRSA isolates were Panton-Valentine leukocidin-positive. Multilocus sequence typing of 72 CA-MRSA isolates revealed that they belonged to ST80 (n = 61), ST30 (n = 6), ST377 (n = 3), ST22 (n = 1), and ST152 (n = 1). Resistance to fusidic acid was observed in ST80 (58/61), ST30 (1/6), and ST22 (1/1) isolates.

Conclusion

In areas with high rate of infections caused by multidrug-resistant CA-MRSA isolates, predominantly belonging to the European ST80 clone, fusidic acid and clindamycin should be used cautiously as empiric therapy in patients with suspected severe staphylococcal infections.

Resistance and the management of complicated skin and skin structure infections: the role of ceftobiprole

Antimicrobial resistant bacteria are an increasing concern due to the resulting increase in morbidity, mortality, and health-care costs associated with the administration of inadequate or delayed antimicrobial therapy. The implications of inadequate antimicrobial therapy in complicated skin and skin structure infections (cSSSIs) have gained more attention recently, most likely due to the recent emergence of community-acquired methicillin resistant Staphylococcus aureus (MRSA) and the already high prevalence of MRSA in the nosocomial setting. Due to the continuous threat of resistance arising and the limitations of currently available agents for the treatment of cSSSIs, it is necessary to develop new antimicrobials for this indication. Ceftobiprole medocaril, the prodrug of ceftobiprole, is a parental investigational cephalosporin for the treatment of cSSSIs displaying a wide-spectrum of activity against both Gram-positive and Gram-negative species, including MRSA. Ceftobiprole displays noncomplex linear pharmacokinetics, is eliminated primarily by glomerular filtration, and distributes to extracellular fluid. Additionally, it has been shown that the extent of distribution to the site of action with regard to cSSSIs, ie, the extracellular space fluid of subcutaneous adipose tissue and skeletal muscle, is expected to be efficacious, as free concentrations meet efficacy targets for most pathogens. Similar to other beta-lactams, it displays an excellent safety and tolerability profile with the primary adverse events being dysgeusia in healthy volunteers, resulting from the conversion of the prodrug to the active, and nausea in patients. Ceftobiprole has demonstrated noninferiority in two large-scale pivotal studies comparing it to vancomycin, clinical cure rates 93.3% vs 93.5%, respectively, or vancomycin plus ceftazidime, clinical cure rates 90.5% vs 90.2%, respectively. Given the pharmacokinetic and pharmacodynamic properties, ceftobiprole is a promising new agent for the treatment of cSSSIs and has the potential to be used as a single agent for empiric treatment.

Recurrent skin and soft tissue infections due to methicillin-resistant Staphylococcus aureus requiring operative debridement

BACKGROUND

The aim of this study was to examine clinical factors associated with the recurrence of community-onset skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus.

METHODS

An observational case-comparison study based on a retrospective review of medical records was conducted in a public health system. All patients with community-onset skin and soft tissue infections caused by methicillin-resistant S aureus who underwent operative debridement from January 1999 to December 2003 were included. The outcome of interest was recurrence within 1 year.

RESULTS

Two hundred fifty-three patients met the criteria for inclusion. Fifty-three (21%) patients returned with recurrent episodes. These patients were compared with 200 patients (79%) who did not develop recurrence. On multivariate analysis, factors independently predictive of recurrence were medical history of abscess requiring surgical debridement within the previous year (adjusted odds ratio, 2.6; 95% confidence interval, 1.4-5.0; P = .002) and obesity (adjusted odds ratio, 3.4; 95% confidence interval, 1.4-8.8; P = .008).

CONCLUSIONS

Patients with obesity or histories of methicillin-resistant S aureus infection are at significantly increased risk for recurrent soft tissue infection.

Community-Associated Methicillin-Resistant Staphylococcus Aureus Skin and Soft Tissue Infections

The prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections is increasing globally and in Singapore. Skin and soft tissue infections (SSTIs) are the most common manifestations, ranging from common furuncles to the rare but life-threatening necrotizing fasciitis. Surgical drainage and debridement where feasible are the mainstay of therapy, whereas MRSA-active antibiotics are essential when surgery is not possible or as adjunctive therapy for severe and/or complicated SSTIs. In itself, the continued inexorable rise in CA-MRSA rates poses difficult challenges for primary healthcare and hospital infection control. Innovative approaches are required to mitigate its impact in both the community and hospital settings.

Pediatric abscess characteristics associated with hospital admission from the ED

OBJECTIVE

To determine the characteristics of pediatric soft tissue abscesses that result in hospital admission.

METHODS

All visits for soft tissue abscesses to the study emergency department (ED) were examined during 2008. Detailed records were reviewed to determine ED disposition, abscess size, location, presence of fever, duration of symptoms, previous antibiotic therapy, prior ED visit(s), and wound and blood culture results. Data were analyzed to determine which of these characteristics were associated with hospital admission from the ED.

RESULTS

Six hundred twenty-two patients met the inclusion criteria. One hundred thirteen (18%) patients were admitted to the hospital and 509 (82%) were discharged home. Compared to those sent home, abscesses resulting in admission were more likely to be located in the genital area (odds ratio [OR], 3.08; 95% confidence interval [CI], 1.37-6.90), breast (OR, 4.8; 95% CI, 1.08-21.4), or face (OR, 4.39; 95% CI, 1.86-10.3), and were more likely to be larger than 3 cm (OR, 3.66, 95% CI, 2.10-6.36). Patients who were admitted to the hospital were also more likely to have fever (OR, 5.93; 95% CI, 3.4-10.3) and have had a prior ED visit with the same complaint (OR, 3.81; 95% CI, 1.77-8.2). Seventy-seven percent of abscesses that were cultured were positive for methicillin-resistant Staphylococcus aureus.

CONCLUSIONS

Size and location (especially those in the genital region, breast, and face), appear to be associated with admission for pediatric abscesses. History of fever and previous ED visit also appear to be associated with hospital admission. Obtaining blood cultures for pediatric abscesses is likely of little clinical benefit.

Methicillin-resistant Staphylococcus aureus in HIV-infected patients

Concordant with the emergence of methicillin-resistant Staphylococcus aureus (MRSA) in the community setting, colonization and infections with this pathogen have become a prevalent problem among the human immunodeficiency virus (HIV)-positive population. A variety of different host- and, possibly, pathogen-related factors may play a role in explaining the increased prevalence and incidence observed. In this article, we review pathophysiology, epidemiology, clinical manifestations, and treatment of MRSA in the HIV-infected population.

Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic

Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

Minimally invasive technique in treatment of complex, subcutaneous abscesses in children

The rising prevalence of community-acquired, methicillin-resistant Staphylococcus aureus (MRSA) has correlated with an escalating number of complex, subcutaneous abscesses in pediatric patients. The purpose of this study was to present a novel technique and early outcome results for the minimally invasive drainage of complex, subcutaneous abscesses.

METHODS

Patients' outcomes from the treatment of complex, subcutaneous abscesses were retrospectively reviewed under institutional review board approval from July 2006 to August 2007 at 2 independent, tertiary care pediatric hospitals. Data on patients' demographics, length of hospital stay, and length of treatment were collected, along with analysis of the isolated organisms. The operative technique uses drainage of the abscess through peripheral stab incisions. Cavity debridement and irrigation is followed by placement of a vessel-loop drain through the drainage incisions. Topical wound care without packing is performed twice a day. Drain removal follows resolution of cellulitis and drainage.

RESULTS

One hundred twenty-eight patients were treated over a 14-month period. The ratio of females to males was 1.25:1. Average patient age was 51.5 months (median, 21 months) and ranged from 5 weeks to 18 years. The average length of hospital stay was 1.5 days, though 30 patients were treated on an outpatient basis. Methicillin-resistant Staphylococcus aureus was identified in 76% of the cultured specimens. Average length of drain use was 9 days (range, 5-29 days). There were no local recurrences of subcutaneous abscesses. There was no morbidity related to the drainage procedures.

CONCLUSION

We present a successful technique for the drainage and treatment of complex abscesses in children with limited, postoperative wound care and no morbidity or recurrence.

Diagnosis and management of community-associated MRSA infections in children

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

Treatment of community-associated methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus has emerged in the community among patient populations without traditional antibiotic resistance risk factors and is causing a variety of clinical syndromes, in particular skin and soft tissue infections. These infections can range from minor skin involvement that can be treated in an outpatient setting to more serious infections such as necrotizing fasciitis requiring hospitalization. Inpatient and outpatient healthcare providers must be aware of the treatment, prevention, and infection control practices for this emerging pathogen.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin infections

PURPOSE OF REVIEW

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become increasingly important as a cause of skin and soft tissue infections (SSTIs), particularly abscesses, in patients seen in the emergency department setting. The antibiotic sensitivity profile of Staphylococcus aureus isolates from SSTIs has changed over time in many geographic locations. Whether antibiotics are needed in the management of skin abscesses, and, if so, when, is controversial.

RECENT FINDINGS

A number of studies have looked at antibiotic therapy in conjunction with incision and drainage in managing abscesses. Factors evaluated were resolution of infection, need for change in antibiotic therapy, hospitalization after initial outpatient management, need for an additional drainage procedure, and recurrence of infection within 30 days after the initial incision and drainage procedure. For abscesses, clinical failure was associated with lack of adequate incision and drainage and not antibiotic use, regardless of the size of the abscess or the choice of antibiotic therapy. For other soft tissue infections, when antibiotic susceptibility data were available for the infection (impetigo or cellulitis with purulent drainage but no abscess), there was no difference in clinical resolution of MRSA infection even if the infecting organism was resistant to the antibiotic chosen for therapy.

SUMMARY

CA-MRSA has become an important cause of SSTIs. Current data suggest that most abscesses can be treated successfully with incision and drainage alone. Antibiotic choice is more crucial for management of cellulitis and should be guided by the prevalence of CA-MRSA in the community and its antibiotic susceptibility profile.

Methicillin-resistant Staphylococcus aureus: from the hospital to the community

Infections due to community-associated methicillin---resistant Staphylococcus aureus (CA-MRSA) are becoming more prevalent. CA-MRSA infections have unique epidemiologic features and virulence factors. Compared with health care-associated MRSA (HA-MRSA), most CA-MRSA is clonal type USA300 or 400 and has the Staphylococcal cassette chromosome mec type IV, which carries the mecA gene that encodes for resistance to methicillin and other beta-lactam antibiotics but generally not for other antibiotics. CA-MRSA often contains various virulence factors that may result in tissue necrosis. CA-MRSA clinical presentation includes mostly skin and soft tissue infections and less frequently pneumonia. In many of the small soft tissue abscesses due to CA-MRSA, primary treatment with surgical drainage may result in improvement without antibiotic therapy. Optimal treatment and prevention of CA-MRSA infections are unclear. However, distinction between CA-MRSA and HA-MRSA may be less relevant in the future, as CA-MRSA strains are now diagnosed in the hospital setting.

Community-associated meticillin-resistant Staphylococcus aureus

Meticillin-resistant Staphylococcus aureus (MRSA) is endemic in hospitals worldwide, and causes substantial morbidity and mortality. Health-care-associated MRSA infections arise in individuals with predisposing risk factors, such as surgery or presence of an indwelling medical device. By contrast, many community-associated MRSA (CA-MRSA) infections arise in otherwise healthy individuals who do not have such risk factors. Additionally, CA-MRSA infections are epidemic in some countries. These features suggest that CA-MRSA strains are more virulent and transmissible than are traditional hospital-associated MRSA strains. The restricted treatment options for CA-MRSA infections compound the effect of enhanced virulence and transmission. Although progress has been made towards understanding emergence of CA-MRSA, virulence, and treatment of infections, our knowledge remains incomplete. Here we review the most up-to-date knowledge and provide a perspective for the future prophylaxis or new treatments for CA-MRSA infections.

Staphylococcus aureus antimicrobial susceptibility of abscess samples from adults and children from the Kaleida Health System in western New York State, 2003 to 2006

Staphylococcus aureus is the most common etiologic agent of skin abscesses. The regional rate of methicillin-resistant S. aureus (MRSA) abscesses may reflect the prevalence of local community-acquired MRSA (CAMRSA). A retrospective study was conducted to compare the antimicrobial susceptibility patterns of S. aureus isolates recovered from abscesses from 2003 to 2006 from patients at hospitals of the Kaleida Health System in western New York. S. aureus susceptibility information was obtained from a Vitek Legacy system, and the location and source of each isolate were identified. EpiInfo software was used to analyze the antimicrobial susceptibilities of all isolates and the trends in the rates of MRSA. A total of 2,848 S. aureus abscesses were identified by the Kaleida Health Clinical Microbiology Laboratory. Of those, 978 S. aureus abscess events occurred in four hospitals, including three adult facilities (547 episodes with 62 cases of bacteremia) and one children's facility (431 episodes with 2 cases of bacteremia). The MRSA rates in adults increased from 56% (2003) to 71% (2006), and that in children increased from 26% (2003) to 64% (2006). Of the MRSA isolates in the children's samples, more than 92% were susceptible to clindamycin. Of the MRSA isolates in the adult samples, 50% were susceptible to clindamycin in 2003 and 2004, whereas greater than 75% were susceptible in 2005 and 2006. The increased rates of MRSA abscesses with susceptibility to clindamycin may reflect the high prevalence level of CAMRSA in the western New York community. The variations in S. aureus susceptibilities could serve as an indicator of the changing resistance patterns within a broad urban community.

Emergency management of pediatric skin and soft tissue infections in the community-associated methicillin-resistant Staphylococcus aureus era

OBJECTIVES

Skin and soft tissue infections (SSTIs) are increasing in incidence, yet there is no consensus regarding management of these infections in the era of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). This study sought to describe current pediatric emergency physician (PEP) management of commonly presenting skin infections.

METHODS

This was a cross-sectional survey of subscribers to the American Academy of Pediatrics Section on Emergency Medicine (AAP SoEM) list-serv. Enrollment occurred via the list-serv over a 3-month period. Vignettes of equivocal SSTI, cellulitis, and skin abscess were presented to participants, and knowledge, diagnostic, and therapeutic approaches were assessed.

RESULTS

In total, 366 of 606 (60.3%) list-serv members responded. The mean (+/- standard deviation [SD]) duration of practice was 13.6 (+/-7.9) years, and 88.6% practiced in a pediatric emergency department. Most respondents (72.7%) preferred clinical diagnosis alone for equivocal SSTI, as opposed to invasive or imaging modalities. For outpatient cellulitis, PEPs selected clindamycin (30.6%), trimethoprim-sulfa (27.0%), and first-generation cephalosporins (22.7%); methicillin-sensitive S. aureus (MSSA) was routinely covered, but many regimens failed to cover CA-MRSA (32.5%) or group A streptococcus (27.0%). For skin abscesses, spontaneous discharge (67.5%) was rated the most important factor in electing to perform a drainage procedure; fever (19.9%) and patient age (13.1%) were the lowest. PEPs elected to prescribe trimethoprim-sulfamethoxazole (TMP-Sx; 50.0%) or clindamycin (32.7%) after drainage; only 5% selected CA-MRSA-inactive agents. All PEPs suspected CA-MRSA as the etiology of skin abscesses, and many attributed sepsis (22.1%) and invasive pneumonia (20.5%) to CA-MRSA, as opposed to MSSA. However, 23.9% remained unaware of local CA-MRSA prevalence for even common infections.

CONCLUSIONS

Practice variation exists among PEPs for management of SSTI. These results can be used to measure changes in SSTI practices as standardized approaches are delineated.

Recent insights into atopic dermatitis and implications for management of infectious complications

Atopic dermatitis (AD) is a common complex disease that frequently follows a chronic relapsing course and affects the quality of life of patients and families in a significant manner. New insights into the pathophysiology of AD point to an important role of structural abnormalities in the epidermis combined with immune dysregulation. Patients with AD have a unique predisposition to colonization or infection by a number of microbial organisms, most notably Staphylococcus aureus and herpes simplex virus. A multipronged approach directed at healing or protecting the skin barrier and addressing the immune dysregulation is necessary to improve the likelihood of successful outcomes.

Community-acquired methicillin-resistant Staphylococcus aureus in surgically treated hand infections

PURPOSE

An increase in the incidence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections has been observed. The purpose of this study is to determine the change in proportion of surgically treated CA-MRSA hand infections over the last decade and to identify associated risk factors.

METHODS

A retrospective review was performed of all 159 hand infections treated in the operating room over an 11-year period (1997-2007). Mean age overall was 40 years, mean inpatient length of stay was 4.9 days, and 115 of the 159 patients were male. Examined data included known risk factors for MRSA, including human immunodeficiency virus infection, diabetes mellitus, intravenous drug use, incarceration, and homelessness.

RESULTS

Forty-eight patients had surgery for hand infections due to CA-MRSA. The yearly proportion of CA-MRSA increased over the study period, and the risk of having an MRSA infection was 41% higher with each progressive calendar year during the study period relative to the apparent incidence of non-MRSA hand infections. Other factors associated with CA-MRSA were intravenous drug use, felon-type infection, and prior hand infection. Multivariable logistic regression identified intravenous drug use as a significant, independent risk factor for CA-MRSA hand infection.

CONCLUSIONS

The proportion of surgically treated hand infections due to CA-MRSA has increased during the last decade. Intravenous drug use was the only independent risk factor for CA-MRSA infections treated in the operating room at our institution.

Changing incidence of methicillin-resistant staphylococcus aureus skin abscesses in a pediatric emergency department

OBJECTIVES

The primary objective of this study was to determine the etiology of skin abscesses in a pediatric emergency department (ED) during a 4-year period and to determine whether the incidence of methicillin-resistant Staphylococcus aureus (MRSA) skin abscesses has increased. The secondary objective was to characterize MRSA infections by antibiotic susceptibility during the same period.

METHODS

A retrospective chart review examining all cases of skin abscess requiring an incision and drainage seen in a free-standing children's hospital ED from January 1, 2003, to December 30, 2006, was performed. Demographic and clinical data were abstracted from the medical records. Culture results, including sensitivities to antibiotics, were obtained to identify how many of these patients had MRSA.

RESULTS

The charts of 442 children were analyzed, and 274 (62%) had MRSA isolated during the entire study period. In 2003, 36.2% of all drained abscesses were caused by MRSA, and by 2006, this increased to 66.5% (P < 0.001). Methicillin-resistant S. aureus isolates were sensitive to trimethoprim-sulfamethoxazole in 99% of the cases, but the sensitivity of MRSA to clindamycin decreased from 96% in 2003 to 87% by 2006. All isolates remain sensitive to rifampin, vancomycin, and gentamicin.

CONCLUSIONS

The incidence of MRSA skin abscesses has increased in the pediatric ED population and now accounts for greater than 50% of all abscesses. If antimicrobial therapy is indicated for the treatment of these abscesses, cultures should be obtained, and antibiotics should be chosen to provide MRSA coverage.

MRSA as a cause of postpartum breast abscess in infant and mother

This report describes the unusual occurrence of mastitis and breast abscess in both mother and infant, both caused by methicillin-resistant Staphylococcus aureus (MRSA). Mother and child were both immunocompetent, and their only risk factor was routine confinement. The case highlights the importance of considering MRSA as a cause for mastitis in mothers and infants. MRSA is increasingly common, and failure to consider it as a cause for mastitis will lead to delays in treatment (as it did in this case). The case also demonstrates the role of Hospital in the Home in the treatment of postnatal infections, where hospitalization can be extremely disruptive.

Update on cutaneous manifestations of infectious diseases

Many emerging pathogens present in the skin and are of interest to dermatologists. Recent epidemics of measles, avian flu, and SARS demonstrated how an organism can rapidly spread worldwide because of airline travel. Travelers are often contagious before they are aware that they have the disease, contributing to the spread. This article reviews bacterial, mycobacterial, fungal, and viral pathogens important to dermatologists.

Community-associated meticillin-resistant Staphylococcus aureus infections: epidemiology, recognition and management

Meticillin-resistant Staphylococcus aureus (MRSA) is an important cause of infection, particularly in hospitalized patients and those with significant healthcare exposure. In recent years, epidemic community-associated MRSA (CA-MRSA) infections occurring in patients without healthcare risk factors have become more frequent. The most common manifestation of CA-MRSA infection is skin and soft tissue infection, although necrotizing pneumonia, sepsis and osteoarticular infections can occur. CA-MRSA strains have become endemic in many communities and are genetically distinct from previously identified MRSA strains. CA-MRSA may be more capable colonizers of humans and more virulent than other S. aureus strains. Specific mechanisms of pathogenicity have not been elucidated, but several factors have been proposed as responsible for the virulence of CA-MRSA, including the Panton-Valentine leukocidin, phenol-soluble modulins and type I arginine catabolic mobile element. The movement of CA-MRSA strains into the nosocomial setting limits the utility of using clinical risk factors alone to designate community- or healthcare-associated status. Identification of unique genetic characteristics and genotyping are valuable tools for MRSA epidemiological studies. Although the optimum pharmacological therapy for CA-MRSA infections has not been determined, many CA-MRSA strains remain broadly susceptible to several non-beta-lactam antibacterial agents. Empirical antibacterial therapy should include an MRSA-active agent, particularly in areas where CA-MRSA is endemic.

Skin and Soft Tissue Abscess: 1 Year's Experience

Background:

The incidence of skin and soft tissue abscesses (SSTAs) has increased owing to the emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Some of these patients are treated as outpatients (OPs) and some as inpatients (IPs).

Objective:

To review the microbiology and clinical features of SSTAs and the clinical parameters that may have influenced clinicians to treat patients as IPs.

Methods:

The study was conducted in a 673-bed teaching hospital between January and December 2005. A retrospective chart review of patients identified from a microbiology culture log was conducted. Data were collected for demographics, underlying disease, SSTA number and site, recurrence rates, and clinical presentation.

Results:

One hundred thirty-eight patients were identified; 76 (55%) were female, with a mean age of 42 years (range 18–80 years); 76 (55.5%) had no underlying disease, 27 (19.6%) had diabetes, 20 (14.5%) had human immunodeficiency virus (HIV) infection, and 13 (9.4%) were intravenous drug users. Common SSTA sites involved were the perineal area (43; 31.2%), upper extremities (35; 25.4%), lower extremities (19; 13.8%), head and neck (14; 10.1%), chest (13; 9.4%), and abdomen (8; 5.8%).

Conclusions:

CA-MRSA was the most commonly isolated organism overall and in patients treated as OPs. The decision to treat SSTA patients as IPs seems to be influenced by SSTA number and site and the presence of fever at presentation. SSTA number and site (variables that led to the decision to treat patients as IPs) were confirmed by demonstrating statistical significance in the analysis between the IP and OP groups, but the other determinant of admission, the presence of fever at presentation, was based on chart review statements and not confirmed by statistical analysis between the IP and OP groups.

Waves of resistance: Staphylococcus aureus in the antibiotic era

Staphylococcus aureus is notorious for its ability to become resistant to antibiotics. Infections that are caused by antibiotic-resistant strains often occur in epidemic waves that are initiated by one or a few successful clones. Methicillin-resistant S. aureus (MRSA) features prominently in these epidemics. Historically associated with hospitals and other health care settings, MRSA has now emerged as a widespread cause of community infections. Community or community-associated MRSA (CA-MRSA) can spread rapidly among healthy individuals. Outbreaks of CA-MRSA infections have been reported worldwide, and CA-MRSA strains are now epidemic in the United States. Here, we review the molecular epidemiology of the epidemic waves of penicillin- and methicillin-resistant strains of S. aureus that have occurred since 1940, with a focus on the clinical and molecular epidemiology of CA-MRSA.

Stevens-Johnson syndrome and toxic epidermal necrolysis: consequence of treatment of an emerging pathogen

We report a case of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) secondary to trimethoprim-sulfamethoxazole (TMP-Sx) therapy for presumed community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection. Although the association between SJS/TEN and the sulfonamide class of antibiotics is well established, the increasing prevalence of CA-MRSA has left practitioners with limited regimens to effectively treat skin and soft tissue infections (SSTIs) in the outpatient setting. In the case of SSTIs, alternative treatment of these infections should be considered, especially when the bacterial pathogen is unknown. Future investigations evaluating the efficacy of adjunctive antibiotics for purulent SSTIs and monitoring the incidence of SJS/TEN in the era of CA-MRSA are necessary to reduce unnecessary use of sulfonamide drugs. The potential development of SJS/TEN, a severe life-threatening illness, emphasizes the need for judicious use of TMP-Sx and close monitoring and follow-up for patients who were given TMP-Sx for SSTIs.

The emergence of severe, community-acquired methicillin-resistant Staphylococcus aureus infections

The number of community acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections is rapidly increasing. Most CA-MRSA infections are localized soft tissue infections; however, severe life-threatening infections have been occasionally described. This report serves to increase the awareness of severe CA-MRSA infections by presenting a fulminant CA-MRSA infection with sepsis, endocarditis, septic pulmonary emboli, and extensive soft tissue and bone destruction. A review of the literature revealed 14 cases of severe CA-MRSA infections with a median age of 13 y; 93% had no underlying medical condition. Only 1 case was initially treated with antibiotics effective for MRSA. The fatality rate was 64%, and 40% of patients who survived had significant disabilities.

Methicillin-susceptible Staphylococcus aureus in skin and soft tissue infections, Northern Italy

Summary statement: A community outbreak with intrafamilial skin infections was associated with an MSSA clone.

During February 2004–September 2006, familial clusters and sporadic cases of Staphylococcus aureus skin and soft tissue infections were observed in a suburban area near Milan in northern Italy. Molecular typing of the isolates showed an epidemic methicillin-susceptible S. aureus (MSSA) strain, spa type 005 and sequence type 22 that harbored Panton-Valentine leukocidin (PVL) genes. The first case-patients were neonates or mothers who had recently delivered in the local hospital. Examination of the medical records showed a cluster of postpartum mastitis and neonatal skin infections antedating the emergence of infections in the community. Nasal swabs of neonates, mothers, and hospital staff were positive for the epidemic MSSA. Hospital circulation of the strain was interrupted by implementation of infection control measures, although infections continued to occur in the community. The PVL-positive MSSA strain resembles typical community-acquired methicillin-resistant S. aureus in its ability to cause prolonged community and hospital outbreaks of skin infections.

Community-associated methicillin-resistant Staphylococcus aureus: trends in case and isolate characteristics from six years of prospective surveillance

OBJECTIVES

In 2000, the Minnesota Department of Health (MDH) implemented active, sentinel site surveillance for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). Data from 2000-2005 were analyzed to determine trends in case characteristics, pulsed-field types (PFTs), and antimicrobial susceptibilities including inducible clindamycin resistance (ICR).

METHODS

Active sentinel site surveillance was initiated in 2000 at 12 hospital laboratories that served inpatients and outpatients. Patient medical records were reviewed to determine if they met the epidemiologic case criteria for CA-MRSA; isolates were obtained from patients meeting these criteria. The MDH Public Health Laboratory performed pulsed-field gel electrophoresis subtyping and antimicrobial susceptibility testing, including ICR.

RESULTS

The proportion of MRSA cases classified as CA increased from 11% to 33% (p<0.01). The proportion of cases with skin or soft tissue infections also increased compared with other infection types from 75% to 87% (p<0.01). During the surveillance period, USA300 replaced USA400 as the dominant PFT. With the change in dominant PFT, the proportion of isolates susceptible to erythromycin (45% to 13%, p<0.01) and ciprofloxacin (80% to 59%, p<0.01) decreased. The proportion of erythromycin-resistant/clindamycin-susceptible isolates with ICR (93% to 14%, p<0.01) decreased. The proportion of susceptible isolates also changed within the USA300 PFT; the proportion of isolates susceptible to erythromycin (33% vs. 3%) and the proportion susceptible to ciprofloxacin (67% to 62%) decreased significantly.

CONCLUSION

CA-MRSA increased dramatically from 2000 to 2005. Changes in the predominant PFT have impacted susceptibility profiles of CA-MRSA, including ICR. Continued surveillance is needed to monitor the changing epidemiology of CA-MRSA and to inform clinical decisions.

Staphylococcus aureus: a community pathogen

Staphylococcus aureus is a common human pathogen. S aureus infections most commonly clinically manifest as skin infections. There has been much interest in S aureus infections in the community over the past decade because of the rise of community-associated methicillin-resistant S aureus (CA-MRSA) infections, which have emerged globally over a relatively short period of time. In contrast to health care-associated methicillin resistant S aureus (HA-MRSA), circulating strains of CA-MRSA have characteristic pathogenesis, strain characteristics, epidemiology, and clinical manifestations that are distinct from HA-MRSA. In fact, CA-MRSA probably behaves more like community-associated methicillin-sensitive S aureus (MSSA). This article reviews current knowledge of the epidemiology and clinical manifestations of community-associated S aureus and CA-MRSA infections.