Prevalence Of Community-associated Methicillin-resistant Staphylococcus Aureus Research Articles

Surveillance of methicillin-resistant Staphylococcus aureus infections obtained from pus sample: A comparison of community- and hospital-acquired infections

Abstract Background: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most common causes of healthcare-associated infections. Recently, the prevalence of community-associated MRSA (CA-MRSA) is increasing affecting individuals with no known risk factors or health-care exposure, blurring the differences between the two. With changing epidemiology of an organism having a natural tendency of fast-developing resistance, MRSA infections need active ongoing surveillance, for effective implementation of appropriate treatment and preventive strategies. Patients and Methods: This was a prospective, observational study conducted in various inpatient departments of a tertiary care teaching hospital in Gujarat, India. MRSA infections were classified as community-acquired-MRSA (CA-MRSA) and hospital-acquired MRSA (HA-MRSA) based on the US CDC 2010 definition. Clinical and epidemiological profile as well as antibiotic sensitivity was assessed in both the groups. An unpaired t-test or Fisher’s exact test was applied to find the difference between the two groups. Results: MRSA isolation rate was 1.42% (60/4212). Ninety percentage of the isolates were multidrug-resistant (MDR), with three being vancomycin-resistant/intermediate. The total duration of hospitalization, number of antimicrobials used after isolation, and duration of therapy were higher in HA-MRSA compared to the CA-MRSA group. The treatment outcome was successful in 86.6% of patients. Conclusion: There is an increasing prevalence of CA-MRSA in the community with the majority of isolates being MDR. These data are alarming and indicate an urgent need for the implementation of strategies directed toward the effective use of appropriate antimicrobials as well as the improvement of hygiene practices in the hospital as well as the community.

Predominance of t355/ST152/SCCmec V clonal type among PVL-positive MRSA isolates in a tertiary care hospital in Belgrade, Serbia.

Epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) is continually changing. Frequency of genotypes typical for community-associated MRSA (CA-MRSA) is increasing in hospitals, as well as resistance to antimicrobial agents. Moreover, different clones predominate in different geographic regions, and temporal shifts occur in the predominant clonal type. The aim of this study was to estimate the prevalence of MRSA, CA-MRSA and PVL-positive MRSA isolates from patients hospitalised in the Military Medical Academy (MMA) and from outpatients, and to perform genotyping of PVL-positive MRSA isolates. MRSA isolates were obtained by standard microbiological techniques. PVL-positive MRSA were detected by single PCR. Determination of SCCmec types in MRSA isolates was done using multiplex PCR and genotyping of PVL-positive MRSA by PFGE, MLST and spa typing. The prevalence of MRSA among S. aureus isolates from different clinical specimens was 43.4%. In outpatients the prevalence of MRSA was 3.2%. SCCmec types specific for CA-MRSA were found in 26% of MRSA isolates from hospitalised patients. In groups, hospitalised patients and outpatients, the prevalence of PVL-positive MRSA isolates was 4%, and all of them harboured SCCmec type V genetic element. PFGE revealed minor differences between four groups of PVL-positive MRSA isolates, but all of them belonged to ST152, and all except one were of the t355 spa type. High prevalence of MRSA and CA-MRSA in MMA, especially the presence of PVL-positive CA-MRSA, represent a serious health threat for patients. Genotype t355/ST152/SCCmec V is the dominant MRSA clone among PVL-positive CA-MRSA.

Epidemiology, evolution and cryptic susceptibility of methicillin-resistant Staphylococcus aureus in China: a whole-genome-based survey

ObjectivesThe aim of this study was to investigate the genomic epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in China to identify predominant lineages and their associations with clinical data and antimicrobial resistance profiles. MethodsWe performed a national prevalence study of patients with S. aureus infections in 22 tertiary hospitals in China from 2015 to 2017. Clinical data from patients and the antimicrobial phenotypes were collected for each isolate. Genome sequencing was performed on a proportion of isolates and a phylogenetic analysis was undertaken. Genotypic and phenotypic β-lactam susceptibilities were compared. ResultsA total of 1900 patients with S. aureus infections were included, of which 40% involved MRSA. Community-associated MRSA (CA-MRSA) infections were 24% of the total isolates. Genomic data showed that more than three-quarters of the MRSA were from three dominant lineages CC239 (25%, 116/471), CC5 (21%, 96/471) and CC59 (33%, 154/471) with CC59 accounting for more than half of the CA-MRSA isolates. Penicillin susceptibility genomic features were observed in 53% (251/470) of MRSA, including almost all of the CC59 (152/154) lineage, and 96% (242/251) of these isolates demonstrated in vitro susceptibility to penicillin or amoxicillin combined with clavulanic acid. Phylogenetic analysis indicated that the CC59 lineage can be divided into six lineages with all Asian CC59 isolates likely arising from an ancestral Mainland China lineage. ConclusionsThis study showed a high prevalence of CA-MRSA in China, largely due to the widespread presence of CC59. As almost all isolates in this lineage possess genetic variants leading to increased β-lactam susceptibility, we suggest that to improve antibiotic stewardship combinations of penicillins and β-lactamase inhibitors should be included in the antibiotic susceptibility testing panels used to inform treatment decisions and research undertaken on this combination therapy.

Prevalence and Characterization of Methicillin-Resistant Staphylococcus aureus from Community- and Hospital-Associated Infections: A Tertiary Care Center Study.

The community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become increasingly prevalent in both community and hospital settings. The aim of this study was to determine the prevalence, molecular characteristics and antibiotic resistance profiles of CA-MRSA from community- and hospital-associated infections in a tertiary care hospital in Mangalore, India. Of 520 S. aureus isolates, 362 were from inpatients (IP) and 158 were from outpatients (OP). One-hundred and thirty-two MRSA isolates obtained from 94 inpatients and 38 outpatients with complete clinical details were further analyzed. Of these, 81 (61.4%) were CA-MRSA (IP-47.9%, OP-94.7%) and 51 (38.6%) were HA-MRSA (IP-52.1%, OP-5.3%). All (100%) MRSA isolates were mecA gene positive. SCCmec typing identified SCCmec type IV (50.6%) and SCCmec type V (66.7%) in CA-MRSA, while SCCmec type I (41.2%), SCCmec type III (19.6%), SCCmec type IV (31.4%) and SCCmec type V (25.5%) were detected in HA-MRSA isolates. The Panton–Valentine Leukocidin (PVL) gene was found in 70.4% of CA-MRSA, 43.1% of HA-MRSA with SCCmec type IV and SCCmec type V, and in 7.8% of true HA-MRSA. The antibiotic resistance profiles were determined by the disc diffusion method. Resistance to cefoxitin was used to identify MRSA. A significant difference (p < 0.05) was observed between CA-MRSA and HA-MRSA with respect to resistance against cephalexin, cefotaxime, levofloxacin, linezolid and teicoplanin. CA-MRSA was predominantly resistant to ciprofloxacin (86.4%), erythromycin (66.7%), ofloxacin (49.4%), cefotaxime (44.4%), gentamicin (40.7%) and clindamycin (40.7%), while HA-MRSA showed resistance against ciprofloxacin (80.4%), erythromycin (80.1%), cefotaxime (70.6%),ofloxacin (58.8%), clindamycin (47.1%) and levofloxacin (41.2%).This study reports the prevalence of CA-MRSA in community and hospital settings and the possibility of multidrug-resistant CA-MRSA replacing HA-MRSA in hospitals. The observations from our study emphasize the need for urgent measures to manage this emerging crisis in healthcare settings.

Can Panton Valentine Leukocidin Gene And Clindamycin Susceptibility Serve As Predictors of Community Origin of MRSA From Skin and Soft Tissue Infections?

Community associated Methicillin-resistant Staphylococcus aureus (CA-MRSA) strains have begun to replace Hospital Associated MRSA (HA-MRSA) strains in hospital settings all over the world. With the epidemiological distinctions between these strains beginning to become ill-defined, the categorisation of a strain as CA-MRSA or HA-MRSA is dependent on molecular methods to detect the presence of SCCmec (Staphylococcal Cassette Chromosome mec) elements. However other markers like the presence of Panton Valentine Leukocidin toxin (pvl) genes or Clindamycin susceptibility may also be associated with community origin of MRSA. To determine the prevalence of CA-MRSA among MRSA strains isolated from skin and soft tissue infections and to evaluate the usefulness of Panton Valentine Leukocidin and Clindamycin susceptibility as markers of community origin of MRSA. One hundred isolates of MRSA from skin and soft tissue were studied for the presence of SCCmec IV and V genes and Panton valentine leukocidin gene by Polymerase chain reaction. Inducible clindamycin resistance was screened for using the D-test. Fischer's exact test. A p-value <0.05 was considered significant. Eighteen out of 100 MRSA strains were found to be CA-MRSA based on presence of SCCmecV. The proportion of Panton Valentine Leukocidin gene carriage among CA- MRSA as compared to HA-MRSA was found to be statistically significant (p<0.0001). Among the CA-MRSA strains, 94.4% were found to be susceptible to Clindamycin as against only 13.4% of the HA-MRSA strains (p<0.0001). The odds of an MRSA strain being CA-MRSA if it was both Clindamycin susceptible and PVL gene positive was calculated to be 68.25 (p<0.0001). Both Clindamycin susceptibility and pvl gene carriage were found to be independent predictors of community origin of MRSA, but taken together the association was highly significant.

Trend in vancomycin susceptibility and correlation with molecular characteristics of methicillin-resistant Staphylococcus aureus causing invasive infections in Taiwan: results from the Tigecycline in vitro Surveillance in Taiwan (TIST) study, 2006–2010

This study was intended to investigate the trend in vancomycin susceptibility and correlation with molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) causing invasive infections. A total of 670 MRSA isolates were collected from patients with invasive infections as part of bacterial collection in the Tigecycline in vitro Surveillance in Taiwan (TIST) from 2006 to 2010. MICs of the isolates to vancomycin were determined using the agar dilution method. Characteristics of staphylococcal cassette chromosome mec (SCCmec), mec-associated hypervariable region (dru), and accessory gene regulator (agr) of the isolates were identified by polymerase chain reaction methods. MRSA isolates with SCCmec types I, II, and III were molecularly defined as hospital-associated MRSA (HA-MRSA), and those with SCCmec types IV, V, and VT were assigned as community-associated MRSA (CA-MRSA). All but 1 MRSA isolates exhibited vancomycin MICs ≤1 mg/L. A declining trend in vancomycin MICs among MRSA isolates was noted, which was associated with the decline in proportion of HA-MRSA. The percentage of CA-MRSA increased from 25.6% in 2006 to 46.0% in 2010. An increase in the geometric mean of vancomycin MICs was found in MRSA with particular molecular types such as SCCmec types II and III, agr groups I and II, and dru10–14. A significant correlation among particular molecular types was found, including SCCmecII–agr group II–dru4, SCCmecIII–agr group I–dru11–14, SCCmecIV–agr group II–dru9, and SCCmecVT–agr group I–dru9 and dru11. There was no vancomycin creep among MRSA isolates, and the declining trend of vancomycin MIC against MRSA was attributed to the increasing prevalence of CA-MRSA over time.

Prevalence and Antibiotic Susceptibility of Community-Associated Methicillin-Resistant Staphylococcus aureus in a Rural Area of India: Is MRSA Replacing Methicillin-Susceptible Staphylococcus aureus in the Community?

Staphylococcus aureus (SA) is the most common cause of skin and soft tissue infections (SSTIs) and nosocomial infections. In developed countries there is a major concern about the rise of community-associated methicillin-resistant SA (CA-MRSA), but data from developing countries are scarce. In this study we describe the prevalence and antibiotic susceptibility of CA-MRSA and healthcare-associated MRSA (HA-MRSA) in a district hospital from rural India. We identified 119 CA-SA infections and 82 HA-SA infections. The majority of infections were SSTI, and the proportion of MRSA in CA-SA and HA-SA infections was 64.7% and 70.7%, respectively. The proportion of CA-MRSA in children <5 years was 73.7%. We did not observe any linezolid or vancomycin resistance. CA-SA had high levels of resistance to ciprofloxacin and low levels of resistance to chloramphenicol, doxycycline, rifampicin, and clindamycin. CA-MRSA had higher proportion of resistance to ciprofloxacin, erythromycin, gentamicin, and cotrimoxazole than CA methicillin-susceptible SA (CA-MSSA). HA-MRSA had higher proportion of resistance to clindamycin and doxycycline than CA-MRSA. The results of this study indicate that MRSA is replacing MSSA in CA-SA infections. If these findings are confirmed by other studies, the spread of CA-MRSA can be a major public health problem in India.

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

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. 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. 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.

Emergency Management of Pediatric Skin and Soft Tissue Infections in the Community‐associated Methicillin‐resistant Staphylococcus aureus Era

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. 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. 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. 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.

Community-associated methicillin-resistant Staphylococcus aureus infections at an Army training installation

To assess the burden of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in a high-risk population, the monthly incidence of laboratory-confirmed MRSA in service members/trainees stationed at Fort Benning, Georgia, USA without hospitalization or surgery documented 30 days prior to infection was calculated for calendar years 2002-2007. Clinical management and antibiotic susceptibility patterns were also evaluated. By 2007, approximately 67% of S. aureus strains were MRSA, and approximately 82% of these were community-associated, primarily in trainees. In total, 3531 CA-MRSA infections were identified. Rates appeared to be seasonal, peaking at 42 cases/1000 soldiers in 2005, with rates remaining above 35/1000 soldiers thereafter. Increased prescription of effective antibiotics was documented. Susceptibility to clindamycin, ciprofloxacin, and levofloxacin decreased from 2002 to 2007 by 6%, 17%, and 14%, respectively. The sustained high prevalence of CA-MRSA observed highlights the need for more vigilant population-based counter-measures at military training installations.

Community-associated methicillin-resistant Staphylococcus aureus: prevalence in skin and soft tissue infections at emergency departments in the Greater Toronto Area and associated risk factors

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA), which is caused primarily by the Canadian methicillin-resistant Staphylococcus aureus-10 (CMRSA-10) strain (also known as the USA300 strain) has emerged rapidly in the United States and is now emerging in Canada. We assessed the prevalence, risk factors, microbiological characteristics and outcomes of CA-MRSA in patients with purulent skin and soft tissue infections (SSTIs) presenting to emergency departments (EDs) in the Greater Toronto Area. Patients with Staphylococcus aureus SSTIs who presented to 7 EDs between Mar. 1 and Jun. 30, 2007, were eligible for inclusion in this study. Antimicrobial susceptibilities and molecular characteristics of MRSA strains were identified. Demographic, risk factor and clinical data were collected through telephone interviews. MRSA was isolated from 58 (19%) of 299 eligible patients. CMRSA-10 was identified at 6 of the 7 study sites and accounted for 29 (50%) of all cases of MRSA. Telephone interviews were completed for 161 of the eligible patients. Individuals with CMRSA-10 were younger (median 34 v. 63 yr, p = 0.002), less likely to report recent antibiotic use (22% v. 67%, p = 0.046) or health care-related risk factors (33% v. 72%, p = 0.097) and more likely to report community-related risk factors (56% v. 6%, p = 0.008) than patients with other MRSA strains. CMRSA-10 SSTIs were treated with incision and drainage (1 patient), antibiotic therapy (3 patients) or both (5 patients), and all resolved. CMRSA-10 isolates were susceptible to clindamycin, tetracycline and trimethoprim-sulfamethoxazole. CA-MRSA is a significant cause of SSTIs in the Greater Toronto Area, and can affect patients without known community-related risk factors. The changing epidemiology of CA-MRSA necessitates further surveillance to inform prevention strategies and empiric treatment guidelines.

Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis

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.

Prevalence of community-associated methicillin-resistantStaphylococcus aureuscolonization outside the healthcare environment

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are increasingly recognized in persons without established risk factors. Population-based prevalence studies of CA-MRSA colonization in persons without risk factors are relatively limited. Subjects aged 2-65 years were enrolled from a student recreation centre, public office building, and out-patient clinics. Persons or close contacts with a history of hospitalization, nursing-home residence, surgery, emergency-department visit, or healthcare employment during the previous year and persons with chronic debilitating illness, indwelling catheter, or surgical device were excluded. Swabs of anterior nares were obtained. Demographic and clinical information was collected. During January-June 2005, three (1.2%) of 259 subjects were colonized with MRSA. All three subjects were adults enrolled at the recreation centre. Healthy persons living in households without recent exposure to healthcare environments were at low risk for MRSA colonization. Studies from other geographic locations are needed to elucidate differences in prevalence of CA-MRSA.

The changing susceptibilities of methicillin-resistant Staphylococcus aureus at a midwestern hospital: The emergence of “community-associated” MRSA

The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has been well described; however, few studies have reviewed long-term hospital-wide data. This retrospective study of adult patients used the first culture per patient per visit positive for MRSA for 1996 to 2005. Isolates were categorized as community-associated or health care-associated phenotype based on antibiotic susceptibilities. chi(2) tests for trend and linear regression analyses were performed. The annual prevalence of CA-MRSA increased significantly over the 10-year study period (from 43 of 507 [8.9%] MRSA cultures in 1996 to 672 of 1697 [39.6%] MRSA cultures in 2005; P < .01). The proportion of MRSA cultures obtained within 48 hours of hospital admission increased from 50.5% to 79.5% (P < .01). The median age of patients with MRSA decreased, from 60 to 49 years (P < .01). Among the CA-MRSA cases, the proportion of non-Caucasian patients increased from 30.2% to 60.4% (P < .01) and the proportion of patients categorized as low socioeconomic status increased from 25.6% to 35.6% (P < .01). Significant consistent trends were not observed for patient sex or body sites of the cultures. An increasing number of MRSA with a community-associated phenotype occurred during the 10-year study period. Patterns of decreasing age, increasing non-Caucasian races, and decreasing socioeconomic status were observed among patients with MRSA.

24: Prevalence of CA-MRSA in Purulent Skin and Soft Tissue Infections in Patients Presenting at Emergency Departments in the Greater Toronto Area

Studies conducted in the US have demonstrated that community associated methicillin resistant Staphylococcus aureus (CA-MRSA) caused primarily by the CMRSA-10 (USA 300) clone has now replaced methicillin-sensitive Staphylococcus aureus (MSSA) as the primary cause of skin and soft tissue infections (SSTI’s). The prevalence of CA-MRSA causing SSTI’s in Canada is unknown; however, small studies in western Canada suggest the prevalence may be as high as 75% in specific communities. The optimal treatment of CA-MRSA SSTI’s has not yet been elucidated.

Injecting drug use and community-associated methicillin-resistant Staphylococcus aureus infection

To demonstrate that injecting drug use is a major risk factor of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection and injecting drug users may be a reservoir of CA-MRSA infection in our community, we conducted a matched case-control study. Cases were CA-MRSA–infected patients at University of California, Davis, Medical Center, Sacramento, CA, from December 1, 2003, to May 31, 2004. Two control groups were community-associated methicillin-susceptible S. aureus (CA-MSSA)-infected patients and a randomly selected uninfected patient group in the same hospital. Controls were matched to cases by age and isolate culture date. One hundred twenty-seven CA-MSSA patients and 381 randomly selected uninfected controls were selected to match the 127 CA-MRSA cases. The adjusted odds ratio of injecting drug use compared with the CA-MSSA group was 2.11 (95% confidence interval [CI], 1.1–4.3) and 4.09 (95% CI, 2.2–7.5) compared with the uninfected group. We suggest that injecting drug use is a significant risk factor for CA-MRSA infection, which could contribute to the increasing prevalence of CA-MRSA in an urban community.

Management of Community-Associated Methicillin-ResistantStaphylococcus aureusInfections in Children

In recent years, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has emerged as a pathogen in children without established risk factors, and its prevalence in the United States is increasing. Although many CA-MRSA infections are mild, primarily involving the skin and soft tissues, the organism can cause serious, invasive, and life-threatening infections. To provide a comprehensive review of the epidemiology, clinical features, therapy, and prevention of CA-MRSA infections in children, we performed MEDLINE (1966-January 2006) and Cochrane Library searches, and reviewed abstracts for relevance to S. aureus infections. Only articles pertaining to CA-MRSA infections in pediatrics were closely examined. As a genetically distinct pathogen, CA-MRSA is generally susceptible to multiple non-beta-lactam antimicrobials. The optimal treatment for CA-MRSA infections in pediatric patients has not been well studied. Common antibiotics used include clindamycin, trimethoprim-sulfamethoxazole, vancomycin, and rifampin. Rational empiric antimicrobial therapy for infections caused by S. aureus requires consideration of the possibility of methicillin resistance. The local prevalence and susceptibilities of CA-MRSA, severity of infection, and individual risk factors should be considered in selecting treatment.

Community-associated Methicillin-resistantStaphylococcus aureus, Switzerland

Two case-control studies evaluated the prevalence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) carriage at hospital admission and characteristics of patients with CA-MRSA. Among 14,253 patients, CA-MRSA prevalence was 0.9/1,000 admissions. Although 5 CA-MRSA isolates contained Panton-Valentine leukocidin, only 1 patient had a previous skin infection. No easily modifiable risk factor for CA-MRSA was identified.