Methicillin-resistant Staphylococcus Aureus Skin Infections Research Articles

Panton–Valentine leukocidin antibodies for the treatment of MRSA skin infections?

Evaluation of: Hermos CR, Yoong P, Pier GB. High levels of antibody to Panton–Valentine leukocidin are not associated with resistance to Staphylococcus aureus-associated skin and soft-tissue infection. Clin. Infect. Dis. 51(10), 1138–1146 (2010).Methicillin-resistant Staphylococcus aureus (MRSA) has recently caused epidemic outbreaks of community-associated (CA) skin infections. The infecting strains frequently contain the genes encoding the staphylococcal toxin, Panton–Valentine leukocidin (PVL). On that ground, the use of PVL-based vaccines has been proposed for the treatment of CA-MRSA infections, despite experimental and epidemiological evidence that does not support a major role of the PVL toxin in CA-MRSA skin disease. Hermos et al. show that antibodies to PVL do not protect from CA-MRSA skin infections in children, strongly suggesting that PVL-based immunization is of little benefit for this most frequent disease caused by CA-MRSA.

Community Acquired MRSA Skin and Soft Tissue Infection and its Possible Relationship With IgG Deficiency and CD4 Lymphopenia

Staphylococcus aureus is the most common pathogen associated with infections of skin and soft tissue structures Staphylococcus aureus colonizes the skin of approximately 35% of Americans of which approximately 1% is methicillin resistant Staphylococcus aureus (MRSA). The vast majority of skin and soft tissue infections have been associated with Community acquired-MRSA strains, but other presentations such as pneumonia, necrotizing fascitis and on rare occasions, septicemia have occurred 4,5 . Risk factors for CA-MRSA infections include being a child, an athlete, a member of the armed forces or an intravenous drug user with the majority of these being immunocompetent 6,7 . CA-MRSA infections have also been reported in patients with immunodeficiency states such as HIV, cancer etc . This study was performed to identify any existing correlations between CA-MRSA skin infections and immunocompromised conditions, as assessed by IgG deficiency and CD4 lymphopenia and to define the local epidemiology of (CA-MRSA) skin infections in El Paso, Texas in an Infectious Disease Clinic over a 3 year period. MATERIAL AND METHODS Data was collected prospectively from the medical and laboratory records of outpatients seen at a Infectious Disease Clinic in El Paso, Texas between 2006 -2009. Inclusion criteria for analysis included: (1) Documented skin and soft tissue infections (SSTIs) , (2) Positive wound cultures obtained just prior to or at the time of evaluation, (3) No known previous history of MRSA colonization or infections, and (4) No recent history of hospitalization, nursing home admission, dialysis, surgery, indwelling catheter or devices that pass through the skin in the past year. Data collected included age, gender, complete blood count (CBC), IgG level and CD4 count. Possible confounders including diabetes, steroid use, cancer or other immunecompromised states and sick contacts were assessed. Description of the lesions included site and characteristics of the infection, as well as the clinical course including surgical intervention, antibiotic therapy and relapses or recurrences. If family members were susupected of having the same presentation, phone interviews or face to face contact was established to determine if they had a reasonable probability of having MRSA skin infections. Any cultures that were done on them by other physicians were reviewed. Patients were followed for an average of 2 years following their initial presentation. The definition of a cure was no further skin and soft tissue infections at the end of the 2 year period.

Angiotensin-converting Enzyme Overexpression in Mouse Myelomonocytic Cells Augments Resistance to Listeria and Methicillin-resistant Staphylococcus aureus

Gene targeting in ES cells was used to substitute control of angiotensin converting enzyme (ACE) expression from the endogenous promoter to the mouse c-fms promoter. The result is an animal model called ACE 10/10 in which ACE is overexpressed by monocytes, macrophages, and other myelomonocytic lineage cells. To study the immune response of these mice to bacterial infection, we challenged them with Listeria monocytogenes or methicillin-resistant Staphylococcus aureus (MRSA). ACE 10/10 mice have a significantly enhanced immune response to both bacteria in vivo and in vitro. For example, 5 days after Listeria infection, the spleen and liver of ACE 10/10 mice had 8.0- and 5.2-fold less bacteria than wild type mice (WT). In a model of MRSA skin infection, ACE 10/10 mice had 50-fold less bacteria than WT mice. Histologic examination showed a prominent infiltrate of ACE-positive mononuclear cells in the skin lesions from ACE 10/10. Increased bacterial resistance in ACE 10/10 is directly due to overexpression of ACE, as it is eliminated by an ACE inhibitor. Critical to increased immunity in ACE 10/10 is the overexpression of iNOS and reactive nitrogen intermediates, as inhibition of iNOS by the inhibitor 1400W eliminated all in vitro and in vivo differences in innate bacterial resistance between ACE 10/10 and WT mice. Increased resistance to MRSA was transferable by bone marrow transplantation. The overexpression of ACE and iNOS by myelomonocytic cells substantially boosts innate immunity and may represent a new means to address serious bacterial infections.

Retrospective cohort study of hospitalized adults treated with vancomycin or clindamycin for methicillin-resistant Staphylococcus aureus skin infections

Background: Vancomycin alternatives, including clindamycin, have in vitro activity against current strains of methicillin-resistant Staphylococcus aureus (MRSA), but clinical evidence of their effectiveness is needed. Objective: The aim of this work was to compare health outcomes for hospitalized adult patients treated with vancomycin and clindamycin for skin and soft- tissue infections caused by MRSA. Methods: This was a retrospective chart review of patients admitted to University Hospital (San Antonio, Texas) with culture-proven MRSA skin or soft-tissue infections from July 1, 2006, to December 31, 2006. Patients were subdivided into groups according to antibiotics received on the first day of hospital admission. The primary outcome was composite failure, which was defined as having an additional positive MRSA culture 5 to 90 days after initial culture or requiring an additional intervention (eg, new course of antibiotics or additional incision and drainage within 90 days after initiation of therapy). Descriptive statistics were used to characterize each group; χ 2, Fisher exact, and Wilcoxon rank sum tests were used to assess differences between the vancomycin and clindamycin groups. Results: Ninety-one patients received vancomycin (n = 40) or clindamycin (n = 51) for a MRSA skin infection. Most vancomycin-treated patients received 1 g IV q12h (92.5% [37/40]), whereas most clindamycintreated patients received 600 mg IV q8h (51.0% [26/51]) or 900 mg IV q8h (27.5% [14/51]). The vancomycin and clindamycin groups had no significant differences with regard to median age (38 vs 37 years, respectively), male sex (62.5% [25/40] vs 74.5% [38/51]), or Hispanic ethnicity (77.5% [31/40] vs 78.4% [40/51]). All MRSA isolates were susceptible to vancomycin and trimethoprimsulfamethoxazole. Few patients who received clindamycin were resistant to clindamycin (3.9% [2/51]). No patients died in the hospital. There were no significant differences between the vancomycin (n = 40) and clindamycin (n = 51) groups with respect to composite failure (15.0% [6/40] vs 7.8% [4/51], respectively), microbiologic failure (2.5% [1/40] vs 3.9% [2/51]), additional inpatient interventions (5.0% [2/40] vs 3.9% [2/51]), or additional outpatient interventions (12.5% [5/40] vs 3.9% [2/51]). Most patients (93.4% [85/91]) received incision and drainage. When those who did not were excluded from the analyses, all trends remained unchanged. Conclusions: In a single institution with a low rate of clindamycin resistance, there were no significant differences between vancomycin and clindamycin for the treatment of these hospitalized patients with MRSA skin infections, on the basis of clinical outcomes data. This finding warrants further investigation in a randomized controlled trial.

Risk Factors for Infection and Colonization with Community‐Associated Methicillin‐ResistantStaphylococcus aureusin the Los Angeles County Jail: A Case‐Control Study

Community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections and outbreaks occur in correctional facilities, such as jails and prisons. Spread of these infections can be extremely difficult to control. Development of effective prevention protocols requires an understanding of MRSA risk factors in incarcerated persons. We performed a case-control study investigating behavioral risk factors associated with MRSA infection and colonization. Case patients were male inmates with confirmed MRSA infection. Control subjects were male inmates without skin infection. Case patients and control subjects completed questionnaires and underwent collection of nasal swab samples for culture for MRSA. Microbiologic analysis was performed to characterize recovered MRSA isolates. We enrolled 60 case patients and 102 control subjects. Of the case patients, 21 (35%) had MRSA nasal colonization, compared with 11 control subjects (11%) (P .001). Among MRSA isolates tested, 100% were the USA300 strain type. Factors associated with MRSA skin infection included MRSA nares colonization, lower educational level, lack of knowledge about "Staph" infections, lower rate of showering in jail, recent skin infection, sharing soap with other inmates, and less preincarceration contact with the health care system. Risk factors associated with MRSA colonization included antibiotic use in the previous year and lower rate of showering. We identified several risks for MRSA infection in male inmates, many of which reflected preincarceration factors, such as previous skin infection and lower educational level. Some mutable factors, such as showering frequency, knowledge about Staph, and soap sharing, may be targets for intervention to prevent infection in this vulnerable population.

Ceftaroline for complicated skin and skin-structure infections

Importance of the field: A dramatic increase in infections caused by methicillin-resistant Staphylococcus aureus (MRSA) has been observed, in part as a result of the epidemic of community-associated MRSA skin and skin-structure infections (SSSIs). Simultaneously, decreasing sensitivities of S. aureus to vancomycin have been reported and invasive infections caused by these strains have been associated with worse clinical outcomes. Clearly, new agents active against MRSA are needed. Ceftaroline is a new cephalosporin active against MRSA and many Gram-negative bacteria, though it is not active against Pseudomonas spp. and extended spectrum β-lactamase producers (ESBL).Areas covered in this review: In this review we focus on the properties of ceftaroline such as in vitro activity, the pharmacokinetic and pharmacodynamic characteristics, and its efficacy and safety observed in the clinical trials of patients with SSSI. Finally, we provide an overview of the possible future role of ceftaroline and other compounds in development for the treatment of SSSIs. The literature search was based on PubMed articles plus review of the abstracts presented in the most important international conferences in the field.What the reader will gain: The reader will gain clear concepts to understand the value that ceftaroline might have in the treatment of SSSIs, including those caused by MRSA.Take home message: Ceftaroline has shown bactericidal activity against common pathogens associated with SSSIs including MRSA, noninferiority in clinical trials of patients with complicated SSSI (cSSSI), and a favorable safety profile.

Photodynamic therapy for methicillin‐resistant Staphylococcus aureus infection in a mouse skin abrasion model

Methicillin-resistant Staphylococcus aureus (MRSA) skin infections are now known to be a common and important problem in the Unites States. The objective of this study was to investigate the efficacy of photodynamic therapy (PDT) for the treatment of MRSA infection in skin abrasion wounds using a mouse model. A mouse model of skin abrasion wound infected with MRSA was developed. Bioluminescent strain of MRSA, a derivative of ATCC 33591, was used to allow the real-time monitoring of the extent of infection in mouse wounds. PDT was performed with the combination of a polyethylenimine (PEI)-ce6 photosensitizer (PS) and non-coherent red light. In vivo fluorescence imaging was carried out to evaluate the effect of photobleaching of PS during PDT. In vivo fluorescence imaging of conjugate PEI-ce6 applied in mice indicated the photobleaching effect of the PS during PDT. PDT induced on average 2.7 log(10) of inactivation of MRSA as judged by loss of bioluminescence in mouse skin abrasion wounds and accelerated the wound healing on average by 8.6 days in comparison to the untreated infected wounds. Photobleaching of PS in the wound was overcome by adding the PS solution in aliquots. PDT may represent an alternative approach for the treatment of MRSA skin infections.

Excretion of Antimicrobials Used to Treat Methicillin‐Resistant Staphylococcus aureus Infections During Lactation: Safety in Breastfeeding Infants

Community-acquired strains of methicillin-resistant Staphylococcus aureus (MRSA) have become a common cause of skin and soft tissue infections in the United States. These infections sometimes require treatment with antibiotics, and with the increasing resistance of pathogens to these agents, choosing the appropriate drug can be difficult. In lactating women who develop these infections, selecting an antibiotic is even more challenging, as clinicians need to be aware of risks to the infant from the drug excreted during lactation. To our knowledge, no review has addressed the safety of antibiotics in breastfeeding infants when the drugs are used to treat maternal skin and soft tissue infections from MRSA. Thus, we performed a literature search of the PubMed-MEDLINE and EMBASE databases (1974-March 2009), reviewed reference citations from identified publications, researched antibiotic prescribing information, and corresponded with drug manufacturers. Case reports, case series, and both in vivo and in vitro clinical trials were evaluated for the following antibiotics: clindamycin, daptomycin, linezolid, quinupristin-dalfopristin, rifampin, tetracycline, doxycycline, minocycline, tigecycline, trimethoprim-sulfamethoxazole, and vancomycin. Information for the newer antibiotics (linezolid, quinupristin-dalfopristin, tigecycline, and daptomycin) was limited. Despite heterogeneity in the data for the older antibiotics (clindamycin, rifampin, tetracyclines, trimethoprim-sulfamethoxazole, and vancomycin), all appear to be relatively safe in the minimal quantities nursing infants ingest through breast milk. Although the risk to infants seems to be relatively low for most of the agents we explored, the paucity of data indicates a need for close monitoring of breastfed infants whose mothers are receiving an antibiotic for an MRSA skin and soft tissue infection.

Linezolid versus vancomycin for MRSA skin and soft tissue infections (systematic review and meta‐analysis)

This review aims to compare the effectiveness of linezolid to vancomycin for the treatment of Methicillin Resistant Staphylococcus Aureus (MRSA) skin and soft tissue infections (SSTIs) in inpatients. MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and reference lists were searched in March 2007. We included randomized controlled trials that looked at inpatients treated with linezolid versus vancomycin for the treatment of hospital-acquired MRSA SSTIs. Outcome measures were clinical cure (resolution of symptoms and signs) and microbiological cure (eradication of MRSA on wound culture). The validity of the included trials was assessed. The results were combined in meta-analyses, the robustness of which was tested in sensitivity analyses. Four trials were included in this review: three for clinical outcomes (174 participants) and three for microbiological outcomes (439 participants). For clinical outcomes there were non-significant trends in favour of linezolid (RR 0.34; 95% CI 0.04, 2.89; P = 0.32). For microbiological outcomes there was weak evidence of linezolid outperforming vancomycin (RR 0.55; 95% CI 0.30, 1.01; P = 0.05). Sensitivity analyses did not change the conclusions taken from the main analysis. With the current available data no difference could be detected between the two treatments, but a trend towards higher effectiveness of linezolid was observed. More data will be required to determine if linezolid is superior to vancomycin for the treatment of MRSA SSTIs. Further systematic reviews are needed to look at other outcomes (length of hospital stay, safety and tolerability, cost-effectiveness) and at MRSA infections at other sites.

Risk Factors for Methicillin-Resistant Staphylococcal aureus Skin and Soft Tissue Infections Presenting in Primary Care: A South Texas Ambulatory Research Network (STARNet) Study

To examine skin and soft tissue infections presenting at 4 primary care clinics and assess if historical risk factors and examination findings were associated with a positive methicillin-resistant Staphylococcus aureus (MRSA) culture. During the 10-month observational study (April 2007 through January 2008), physicians in 5 practices across South Texas collected history, physical examination findings, culture results, and antibiotic(s) prescribed for all patients presenting with a skin or soft tissue infection. Analyses were conducted to determine the relationship between historical indicators, location of lesions, and examination findings with a positive MRSA culture. Across 4 practices, 164 cases of skin and soft tissue infections were collected during 10 months. Of the 94 with a culture, 63 (67%) were MRSA positive. Patients working in or exposed to a health care setting were more likely to have a culture positive for MRSA, as were those presenting with an abscess. MRSA-positive lesions were also significantly smaller in size. Because of the high prevalence of MRSA skin and soft tissue infections among patients presenting to family physicians, presumptive treatment for MRSA may be indicated. However, increasing levels of resistance to current antibiotics is concerning and warrants development of alternative management strategies.

Colonization and Subsequent Skin and Soft Tissue Infection Due to Methicillin‐ResistantStaphylococcusaureusin a Cohort of Otherwise Healthy Adults Infected with HIV Type 1

Methicillin-resistant Staphylococcus aureus (MRSA) carriage and subsequent infection were prospectively compared among a well-defined group of 107 individuals infected with human immunodeficiency virus type 1 (HIV-1) who had no evidence of immune suppression and 52 epidemiologically matched, uninfected individuals. The carriage strains and infecting strains were genetically characterized. The cumulative prevalence of MRSA carriage was significantly higher among HIV-infected individuals (16.8%) than among individuals without HIV infection (5.8%) (P = .04; odds ratio, 3.3 [95% confidence interval, 1.3-14.7]). Fifteen of 21 MRSA isolates recovered from colonized individuals were identified as strain USA300. Of the 10 MRSA skin and soft tissue infections observed in this study, all occurred in HIV-infected individuals who were colonized with the same strain that caused the infection. Previous antibiotic use was the only statistically significant risk factor for MRSA carriage. These data highlight the fact that MRSA colonization and infection are important clinical issues among asymptomatic HIV-1-infected individuals.

Methicillin-resistant Staphylococcus aureus (MRSA) in the Athlete

Although once considered only a nosocomial pathogen, methicillin-resistant Staphylococcus aureus (MRSA) is a rapidly emerging, problematic infection in the community. Community acquired MRSA (CA-MRSA) is notably becoming more prevalent in athletic environments and unfortunately, can be easily transmitted via superficial abrasions and minor skin trauma. CA-MRSA infections are highly contagious and are associated with significant morbidity, with published reports of up to 70% of infected team members requiring hospitalization and intravenous antibiotics . Risk factors for athletic related environments include contact sports with repeated close physical contact with other competitors, open abrasions, and sharing of personal equipment. Failure to correctly diagnose and appropriately treat skin and soft tissue lesions infected with CA-MRSA may contribute to large scale MRSA infections in athletic environments. The purpose of this review article is to help sports medicine physicians prevent, identify, and treat MRSA skin and superficial soft tissue infections in athletic environments.

Prevalence of Methicillin-Resistant Staphylococcus aureus in the Setting of Dermatologic Surgery

The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in the postoperative setting of dermatologic surgery is unknown. Such data could influence the empirical treatment of suspected infections. To examine the period prevalence of MRSA infections in the postoperative setting of dermatologic surgery. We performed chart reviews of 70 patients who had bacterial cultures taken from January 2007 to December 2007. In the 21 postsurgical cases, we analyzed age, risk factors, sites of predilection, method of repair, and pathogen of growth. The mean age of the overall study population was 57, with the mean age of postsurgical MRSA-positive cases being 75.5. Of the 21 postsurgical cultures taken, 16 cultures grew pathogen, and two of the 16 (13%) pathogen-positive cultures grew MRSA. This is a retrospective chart review of a relatively small sample size in one geographic location. Our patient population is known to contain a large number of retirees. The increasing prevalence of MRSA skin and soft tissue infections and recommendation to modify empirical antibiotic therapy have been well documented in particular patient populations, but we caution against the empirical use of MRSA-sensitive antibiotics in the postoperative setting of dermatologic surgery. We advocate culturing all infectious lesions upon presentation and reserve empirical use of MRSA-sensitive antibiotics for high-risk patients or locations.

Molecular Epidemiology of Methicillin-ResistantStaphylococcus aureus, Rural Southwestern Alaska1

USA300 is the dominant strain responsible for community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) infections in most of the United States. We examined isolates from outbreaks of MRSA skin infections in rural southwestern Alaska in 1996 and 2000 (retrospective collection) and from the hospital serving this region in 2004-2006 (prospective collection). Among 36 retrospective collection isolates, 92% carried Panton-Valentine leukocidin (PVL) genes; all carried staphylococcal chromosomal cassette mec (SCCmec) type IV. None belonged to clonal complex (CC) 8, the CC associated with USA300; 57% were sequence type (ST) 1, and 26% were ST30; 61% were clindamycin resistant. In the prospective collection, 42 isolates were PVL+ and carried SCCmec type IV; 83.3% were ST1, 9.5% were ST30, and 7.1% were ST8. Among 120 prospective isolates, 57.5% were clindamycin resistant. CA-MRSA epidemiology in southwestern Alaska differs from that in the lower 48 states; ST8 strains were rarely identified and clindamycin resistance was common.

Incidence des Staphylococcus aureus résistants à la méticilline dans les infections cutanées de l’enfant survenues en milieu communautaire : étude rétrospective 2000–2005

A dramatic increase in the incidence of methicillin-resistant Staphylococcus aureus (MRSA) in community-onset skin infections has been reported over the last 10 years in the USA. The emergence of MRSA has been recently described in France. The aims of this study were to assess the incidence of MRSA in community-onset skin infections and to analyse the characteristics of MRSA skin infections in a French paediatric population.This is a retrospective study covering the period January 2000 to December 2005. Patients aged under 15 years with S. aureus isolated from skin and a clinical diagnosis of skin infection were included.One hundred and thirty-four children were included with a median age of 3.4 years. There were no significant differences in MRSA prevalence between the different years of the study. The overall prevalence of MRSA was 8.2% (n=11/134). None of the isolated strains presented an antimicrobial susceptibility profile suggestive of the ST80-type community-acquired MRSA described in France. Three MRSA strains were isolated from serious superantigen-mediated skin infections. The antimicrobial susceptibility and genetic profile (tst-positive agr2 MSRA) for one strain of S. aureus militated strongly in favour of an MRSA ST5 clone skin infection.In this study we found no evidence of epidemic spread of MRSA in community-onset childhood skin infections between 2000-2005. Nevertheless, we report three cases of serious MRSA-induced superantigen-associated skin infection. This argues in favour of the presence of virulent community MRSA clones in France.

A Review of Community-Associated Methicillin-Resistant Staphylococcus aureus Skin and Soft Tissue Infections

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a cause of infection among otherwise healthy children and adults in the community. Skin and soft tissue infections are most common, but invasive manifestations also occur. A limited number of strains that may possess unique virulence or transmissibility factors have accounted for the majority of these infections. These strains emerged in the community but now are being transmitted in both community and healthcare settings. Incision and drainage remains the primary treatment for skin abscesses. Strains of MRSA circulating in the community generally are susceptible to a number of nonbeta-lactam antimicrobial agents, although resistance patterns may vary temporally and geographically. Educating patients on strategies to prevent further transmission is a critical component of case management. More data are needed to determine optimal strategies for management and prevention of MRSA skin infections in the community.

METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS AS A CAUSE OF EXTENSIVE RETROPHARYNGEAL ABSCESS IN TWO INFANTS

We report 2 cases of extensive methicillin-resistant Staphylococcus aureus (MRSA) retropharyngeal abscesses in young infants. In 1 case, the abscess was associated with a reactive thrombosis of the jugular vein. Based on the existing literature and the rapid emergence of MRSA skin and soft tissue infections, it is possible that similar severe infections will occur with increasing frequency in young infants.

Methicillin-ResistantStaphylococcus aureusInfections

To the Editor: In his review of skin and softtissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA), Daum (July 26 issue)1 cites a study2 indicating that intravenous trimethoprim–sulfamethoxazole (TMP-SMX) is significantly less effective than vancomycin for the treatment of serious S. aureus infections. However, in this randomized, double-blind, comparative trial of TMP-SMX and vancomycin, therapeutic failures occurred only in patients with methicillin-susceptible S. aureus (MSSA) infections. TMP-SMX was successful in treating all MRSA infections, including tricuspid-valve endocarditis. Clinical failures commonly occurred with MSSA tricuspid-valve endocarditis; otherwise, the cure rates with TMPSMX and with vancomycin were similar. On the basis of the results of this study, vancomycin may be superior for MSSA infections; however, the same cannot be concluded for MRSA infections. Although the currently available clinical data for community-associated MRSA skin infections are sparse, in this era of an increasing incidence of MRSA infection and concern about the variable efficacy of vancomycin, TMP-SMX may be a useful alternative in selected cases.

Bag and Mask Ventilation

To the Editor: In his review of skin and softtissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA), Daum (July 26 issue)1 cites a study2 indicating that intravenous trimethoprim–sulfamethoxazole (TMP-SMX) is significantly less effective than vancomycin for the treatment of serious S. aureus infections. However, in this randomized, double-blind, comparative trial of TMP-SMX and vancomycin, therapeutic failures occurred only in patients with methicillin-susceptible S. aureus (MSSA) infections. TMP-SMX was successful in treating all MRSA infections, including tricuspid-valve endocarditis. Clinical failures commonly occurred with MSSA tricuspid-valve endocarditis; otherwise, the cure rates with TMPSMX and with vancomycin were similar. On the basis of the results of this study, vancomycin may be superior for MSSA infections; however, the same cannot be concluded for MRSA infections. Although the currently available clinical data for community-associated MRSA skin infections are sparse, in this era of an increasing incidence of MRSA infection and concern about the variable efficacy of vancomycin, TMP-SMX may be a useful alternative in selected cases.

Methamphetamine Use and Methicillin-ResistantStaphylococcus aureusSkin Infections

Methicillin-resistant Staphylococcus aureus (MRSA) infections and methamphetamine use are emerging public health problems. We conducted a case-control investigation to determine risk factors for MRSA skin and soft tissue infections (SSTIs) in residents of a largely rural southeastern community in the United States. Case-patients were persons >12 years old who had culturable SSTIs; controls had no SSTIs. Of 119 SSTIs identified, 81 (68.1%) were caused by MRSA. Methamphetamine use was reported in 9.9% of case-patients and 1.8% of controls. After we adjusted for age, sex, and race, patients with MRSA SSTIs were more likely than controls to have recently used methamphetamine (odds ratio 5.10, 95% confidence interval 1.55-16.79). MRSA caused most SSTIs in this population. Transmission of MRSA may be occurring among methamphetamine users in this community.