Recurrent Skin And Soft Tissue Infections Research Articles

The Incidence of Skin and Soft Tissue Infections in the United States and Associated Healthcare Utilization Between 2010 and 2020.

The number of patients with skin and soft tissue infections (SSTIs) in the United States appeared to be increasing well into the 21st century. However, no recent data have confirmed this trend. This retrospective, observational cohort study used claims data over 11 years (2010-2020) from Optum's de-identified Clinformatics Data Mart Database. SSTI episodes, complications, and comorbidities were identified using International Classification of Diseases codes. Annual SSTI incidence rates, proportions of recurrent SSTI, SSTI-associated deaths, and total costs were estimated. During the study period, 5.4 million patients experienced 9.1 million SSTI episodes, with an incidence of 77.5 (95% confidence interval, 77.4-77.5) per 1000 person-years of observation (PYO). Annual incidence did not change significantly over time. Overall incidence (per 1000 PYO) of SSTI episodes in patients without comorbidities was 32.1 (highest incidence was for previous SSTI [113.5]) versus much higher rates if comorbidities were present. Incidence rates (per 1000 PYO) of chronic ulcers increased over time from 11.3 to 18.2 (P < .0001) and complicated disease from 3.5 to 6.3 (P < .0001). Deaths occurring within 30 days post-SSTI hospitalization rose from 2.6% to 4.6% in 2020. Recurrences occurred in 26.3% of index cases. The mean cost of an SSTI episode was US$3334 (median US$190) and was highest for surgical site infections and chronic ulcers. The epidemiology of SSTI in the United States is changing and the disease burden is increasing despite stabilization in overall incidence. These data can inform identification of priority populations who could benefit from targeted interventions.

Comparative Effectiveness Study of Home-Based Interventions to Prevent CA-MRSA Infection Recurrence.

Recurrent skin and soft tissue infections (SSTI) caused by Community-Associated Methicillin-Resistant Staphylococcus aureus (CA-MRSA) or Methicillin-Sensitive Staphylococcus aureus (CA-MSSA) present treatment challenges. This community-based trial examined the effectiveness of an evidence-based intervention (CDC Guidelines, topical decolonization, surface decontamination) to reduce SSTI recurrence, mitigate household contamination/transmission, and improve patient-reported outcomes. Participants (n = 186) were individuals with confirmed MRSA(+)/MSSA(+) SSTIs and their household members. During home visits; Community Health Workers/Promotoras provided hygiene instructions; a five-day supply of nasal mupirocin; chlorhexidine for body cleansing; and household disinfecting wipes (Experimental; EXP) or Usual Care Control (UC CON) pamphlets. Primary outcome was six-month SSTI recurrence from electronic health records (EHR). Home visits (months 0; 3) and telephone assessments (months 0; 1; 6) collected self-report data. Index patients and participating household members provided surveillance culture swabs. Secondary outcomes included household surface contamination; household member colonization and transmission; quality of life; and satisfaction with care. There were no significant differences in SSTI recurrence between EXP and UC in the intent-to-treat cohort (n = 186) or the enrolled cohort (n = 119). EXP participants showed reduced but non-significant colonization rates. EXP and UC did not differ in household member transmission, contaminated surfaces, or patient-reported outcomes. This intervention did not reduce clinician-reported MRSA/MSSA SSTI recurrence. Taken together with other recent studies that employed more intensive decolonization protocols, it is possible that a promotora-delivered intervention instructing treatment for a longer or repetitive duration may be effective and should be examined by future studies.

Environmental Methicillin-resistant Staphylococcus aureus Contamination, Persistent Colonization, and Subsequent Skin and Soft Tissue Infection

The longitudinal association among persistent Staphylococcus aureus colonization, household environmental contamination, and recurrent skin and soft tissue infection (SSTI) is largely unexplored to date. To identify factors associated with persistent S aureus colonization and recurrent SSTI in households with children with community-associated methicillin-resistant S aureus (MRSA) SSTI. This 12-month prospective cohort study included 150 children with community-associated MRSA SSTI, 542 household contacts, and 154 pets enrolled from January 3, 2012, through October 20, 2015. A total of 5 quarterly home visits were made to 150 households in the St Louis, Missouri, region. Statistical analysis was performed from September 18, 2018, to January 7, 2020. Covariates used in S aureus strain persistence and interval SSTI models included S aureus colonization and contamination measures, personal hygiene and sharing habits, health history, activities external to the home, and household characteristics (eg, cleanliness, crowding, home ownership, and pets). Serial samples to detect S aureus were collected from household members at 3 anatomic sites, from pets at 2 anatomic sites, and from environmental surfaces at 21 sites. Molecular epidemiologic findings of S aureus isolates were assessed via repetitive-sequence polymerase chain reaction. Individual persistent colonization was defined as colonization by an identical strain for 2 consecutive samplings. Longitudinal, multivariable generalized mixed-effects logistic regression models were used to assess factors associated with persistent S aureus personal colonization, environmental contamination, and interval SSTI. Among 692 household members in 150 households, 326 (47%) were male and 366 (53%) were female, with a median age of 14.82 years (range, 0.05-82.25 years). Of 540 participants completing all 5 samplings, 213 (39%) were persistently colonized with S aureus, most often in the nares and with the strain infecting the index patient at enrollment. Nine pets (8%) were persistently colonized with S aureus. Participants reporting interval intranasal mupirocin application were less likely to experience persistent colonization (odds ratio [OR], 0.44; 95% credible interval [CrI], 0.30-0.66), whereas increasing strain-specific environmental contamination pressure was associated with increased individual persistent colonization (OR, 1.17; 95% CrI, 1.06-1.30). Strains with higher colonization pressure (OR, 1.47; 95% CrI, 1.25-1.71) and MRSA strains (OR, 1.57; 95% CrI, 1.16-2.19) were more likely to persist. Seventy-six index patients (53%) and 101 household contacts (19%) reported interval SSTIs. Individuals persistently colonized with MRSA (OR, 1.56; 95% CrI, 1.17-2.11), those with a history of SSTI (OR, 2.55; 95% CrI, 1.88-3.47), and index patients (OR, 1.54; 95% CrI, 1.07-2.23) were more likely to report an interval SSTI. The study findings suggest that recurrent SSTI is associated with persistent MRSA colonization of household members and contamination of environmental surfaces. Future studies may elucidate the effectiveness of specific combinations of personal decolonization and environmental decontamination efforts in eradicating persistent strains and mitigating recurrent SSTIs.

Comparison of livestock-associated and community-associated Staphylococcus aureus pathogenicity in a mouse model of skin and soft tissue infection

Industrial hog operation (IHO) workers are at increased risk of carrying Staphylococcus aureus in their nares, particularly strains that are livestock-associated (LA) and multidrug-resistant. The pathogenicity of LA-S. aureus strains remains unclear, with some prior studies suggesting reduced transmission and virulence in humans compared to community-associated methicillin-resistant (CA-MRSA) S. aureus. The objective of this study was to determine the degree to which LA-S. aureus strains contracted by IHO workers cause disease relative to a representative CA-MRSA strain in a mouse model of skin and soft tissue infection (SSTI). Mice infected with CC398 LA-S. aureus strains (IHW398-1 and IHW398-2) developed larger lesion sizes with higher bacterial burden than mice infected with CA-MRSA (SF8300) (p < 0.05). The greatest lesion size and bacterial burden was seen with a CC398 strain that produced a recurrent SSTI in an IHO worker. The LA-S. aureus infected mice had decreased IL-1β protein levels compared with CA-MRSA-infected mice (p < 0.05), suggesting a suboptimal host response to LA-S. aureus SSTIs. WGSA revealed heterogeneity in virulence factor and antimicrobial resistance genes carried by LA-S. aureus and CA-MRSA strains. The observed pathogenicity suggest that more attention should be placed on preventing the spread of LA-S. aureus into human populations.

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

Staphylococcus aureus skin and soft tissue infections (SSTI) are a major source of morbidity. More than half of patients experiencing SSTI will have at least one recurrent infection. These infections frequently cluster in households. Given the burden these infections pose to patients and healthcare, prevention strategies are of major clinical importance and represent an active area of research. Bacterial colonization is frequently an early and critical step in the pathogenesis of infection. As such, strategies to prevent reinfection have aimed to decrease staphylococcal colonization of the skin and mucus membranes, a process referred to as decolonization. Treatment of acute SSTI with incision and drainage and systemic antibiotics is the mainstay of therapy for healing of the acute infection. Systemic antibiotics also provide benefit through reduced incidence of recurrent SSTI. Education for patients and families regarding optimization of personal and household hygiene measures, and avoidance of sharing personal hygiene items, is an essential component in prevention efforts. For patients experiencing recurrent SSTI, or in households in which multiple members have experienced SSTI, decolonization should be recommended for all household members. A recommended decolonization regimen includes application of intranasal mupirocin and antiseptic body washes with chlorhexidine or dilute bleach water baths. For patients who continue to experience recurrent SSTI, periodic decolonization should be considered. Personal decolonization with topical antimicrobials and antiseptics reduces the incidence of recurrent S. aureus SSTI. Future avenues for investigation include strategies for household environmental decontamination as well as manipulation of the host microbiota.

Genomic epidemiology of MRSA infection and colonization isolates among military trainees with skin and soft tissue infection.

Individuals with methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infection (SSTI) can be simultaneously colonized with MRSA on multiple body sites. Using whole genome sequencing (WGS), the intrahost relatedness of MRSA colonization and infection isolates was investigated. In the context of a prospective case-control study of SSTI, we analyzed colonization and infection isolates from US Army Infantry trainees with purulent infection due to MRSA. At the time of clinical presentation for SSTI, culture swabs were obtained from the infection site, as well as from the patient's nasal, oral, inguinal, and perianal regions. S. aureus culture and susceptibility was performed by standard methods. DNA from MRSA isolates was extracted and libraries were produced. Sequences were generated on an Illumina MiSeq, sequence reads were assembled, and single nucleotide variant (SNV) data were analyzed. Of 74 trainees with MRSA SSTI, 19 (25.7%) were colonized with MRSA. Ten (52.6%) were colonized on more than one body site. Colonization frequency by anatomic site was as follows: inguinal region (33%), nasal region (30%), perianal region (22%), and oral region (14%). A total of 36 MRSA colonization isolates were characterized. The intrahost median number of SNVs between infection and colonization isolates was 17. Among trainees with recurrent MRSA SSTI, limited intrahost diversity suggests that persistent colonization is a major contributor to recurrence risk. Among military trainees with MRSA SSTI, genomic characterization of infection and colonization isolates revealed a high degree of strain relatedness. Single acquisition events may account for MRSA colonization and infection in this population.

2080 Implementing and evaluating an evidence-based intervention from the intensive care unit (ICU) setting into primary care using promotoras to reduce CA-MRSA recurrence and household transmission

OBJECTIVES/SPECIFIC AIMS: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections (SSTIs) recurrence ranges from 16% to 43% and presents significant challenges to clinicians, patients, and families. This comparative effectiveness research study aims to disseminate, implement and evaluate whether an existing intervention, consisting of decolonization and decontamination procedures, which has been determined to be effective in hospital intensive care unit settings, can be implemented by Community Health Workers (CHWs) or “promotoras” conducting home visits prevent recurrence of CA-MRSA and transmission within their households for patients presenting to primary care with SSTIs. METHODS/STUDY POPULATION: In partnership with 3 Community Health Centers and 4 community hospitals in NYC, this study will recruit patients (n=278) with confirmed MRSA SSTIs and their household members. Participants are randomized to receive either a CHW/Promotora-delivered decolonization-decontamination intervention or usual care, which includes hygiene education. The highly engaged stakeholder team meets monthly to review interim results, identify areas for refinement and new research questions, and develop and implement strategies to improve participant engagement and retention. RESULTS/ANTICIPATED RESULTS: MRSA and MSSA were found in 19% and 21.1% of wound cultures, respectively. 59.5% with MRSA+ wound culture had one or more MRSA+ surveillance culture; 67.8% with MSSA+ wound culture had one or more MSSA+ surveillance culture. The “warm handoff” approach, developed and implemented by the stakeholder team to engage patients from their initial consent to return of lab results and scheduling of the home visits, helped improve completion of baseline home visits by 14%, from 45% to 59% of eligible participants. Home visits have demonstrated that 60% of households had at least one surface contaminated with S. aureus. Of the surfaces that tested positive in the households, nearly 20% were MRSA and 81% were MSSA; 32.5% of household members had at least one surveillance culture positive for S. aureus (MRSA: 7.7%, MSSA: 92.3%). DISCUSSION/SIGNIFICANCE OF IMPACT: This study aims to understand the systems-level, patient-level, and environmental-level factors associated with SSTI recurrence and household transmission, and to examine the interactions between bacterial genotypic and clinical/phenotypic factors on decontamination, decolonization, SSTI recurrence and household transmission. This study will evaluate the barriers and facilitators of implementation of home visits by CHWs in underserved populations, and aims to strengthen the weak evidence base for implementation of strategies to reduce SSTI recurrence and household transmission.

Antibiotics, S aureus Colonization, and Recurrent Skin Infections

Research Article| February 01 2018 Antibiotics, S aureus Colonization, and Recurrent Skin Infections AAP Grand Rounds (2018) 39 (2): 16. https://doi.org/10.1542/gr.39-2-16 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Antibiotics, S aureus Colonization, and Recurrent Skin Infections. AAP Grand Rounds February 2018; 39 (2): 16. https://doi.org/10.1542/gr.39-2-16 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: microbial colonization, skin diseases, infectious, staphylococcus aureus, skin and soft tissue infections, clindamycin Source: Hogan PG, Rodriguez M, Spenner AM, et al. Impact of systemic antibiotics on Staphylococcus aureus colonization and recurrent skin infection [published online ahead of print August 24, 2017. Clin Infect Dis. doi: https://doi.org/10.1093/cid/cix754 Investigators from Washington University, St. Louis, MO, and Southern Illinois University, Springfield, IL, assessed the effect of systemic antibiotics prescribed at the time of incision and drainage (I&D) for Staphylococcus aureus skin and soft tissue infections (SSTI) on rates of future colonization and recurrent infections in children. The investigators combined data from a series of prospective studies, conducted in patients <21 years old with S aureus SSTI since 2008. At the time of I&D (baseline), swabs of the anterior nares, inguinal folds, and axillae of study participants were obtained. For the current study, only children who had S aureus colonization at one or more of these sites were included. Additional data collected at baseline included demographics, decolonization measures (intranasal mupirocin, dilute bleach, or chlorhexidine body washes), whether the infecting S aureus was methicillin-sensitive (MSSA) or resistant (MRSA), and whether the child received antibiotics recommended by the Infectious Diseases Society of America (eg, clindamycin or trimethoprim-sulfamethoxazole [TMP-SMZ]).1 Repeat swabs to determine colonization status were done up to 3 months after baseline. In addition, follow-up data were collected for up to a year after baseline to assess for recurrent SSTI. Cox regression was used to assess the association between use of a guideline-recommended antibiotic at baseline on future colonization or recurrent SSTI, after adjusting for age, race, SSTI isolate (MRSA or MSSA), and number of anatomic sites colonized at baseline. Data were analyzed on 383 children with a median age of 3 years. Overall, 81% of baseline SSTI were caused by MRSA. Baseline colonization was most often detected in inguinal folds, followed by anterior nares; 46% of study participants were colonized at multiple sites. At the time of I&D, 93% of children were prescribed a guideline-recommended antibiotic (clindamycin or TMP-SMZ). Follow-up colonization data were collected on 357 participants. The risk of S aureus colonization at follow-up was significantly lower for children receiving recommended antibiotics compared to those receiving non-recommended or no antibiotics at baseline (colonization rates 48% and 77%, respectively, adjusted hazard ratio [aHR] 0.49, 95% CI 0.30, 0.79). Children receiving clindamycin at baseline were significantly less likely to be colonized at follow-up than those receiving TMP-SMZ (44% and 57%, respectively; P = .03). Recurrent SSTI occurred in 40% of children receiving a recommended antibiotic at baseline vs 64% of those receiving a non-recommended or no antibiotic (aHR = 0.57, 95% CI 0.34, 0.94). The authors conclude that use of clindamycin or TMP-SMZ at the time of I&D in children with an SSTI caused by S aureus reduces the risk of future colonization and rates of recurrent SSTI. Dr Dubik has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device. The results of this study join others supporting... You do not currently have access to this content.

2421

OBJECTIVES/SPECIFIC AIMS: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections (SSTIs) are commonly seen in primary care, with recurrence rates that range from 16% to 43%, and present significant challenges to clinicians, patients, and families. This comparative effectiveness research study aims to develop and evaluate a home-based intervention implemented by Community Health Workers (CHWs) or “promotoras” to prevent recurrence of CA-MRSA in patients presenting to primary care with SSTIs and transmission within their households. This presentation will examine associations between wound microbiology, clinical presentation, and housing characteristics, including housing density and household surfaces contamination. METHODS/STUDY POPULATION: In partnership with 3 Community Health Centers and 3 community hospitals in NYC, this study will recruit patients (n=278) with confirmed MRSA SSTIs and their household members. Participants will be randomized to receive either a CHW/Promotora-delivered decolonization-decontamination intervention (based on the REDUCE MRSA trial) or usual care. The highly engaged stakeholder team finalized the intervention protocol, developed and implemented CHW and clinician training, and developed an online health portal application for data management and exchange. RESULTS/ANTICIPATED RESULTS: We have collected 923 isolates from 237 individuals, including 240 wound culture isolates and 683 surveillance culture isolates (nares, axilla, groin). MRSA and MSSA were found in 19% and 21.1% of wound cultures, respectively; 59.5% with MRSA+ wound culture had 1 or more MRSA+ surveillance culture; 67.8% with MSSA+ wound culture had 1 or more MSSA+ surveillance culture. Of those with MRSA or MSSA infections, 70% of subjects were male, with an average age of 37.9 (SD=15.9 y). The most frequent sites of infection were the leg (20%), axilla (18%), buttock (17%), and abdomen/torso (12%). There was no association between the location and type of infection (MRSA/MSSA) (p-value=0.09). The kitchen floor (14.05%) and bedroom floor (14%) were the most common surfaces contaminated with MRSA. These were also the most common surfaces contaminated with MSSA, which was recovered from 10.2% and 9.1% of kitchen floors and bedroom floors, respectively. For individuals with an MRSA or MSSA wound infection, there was an average number of 3.2 (SD=1.6) co-residents per household, and 36.5% of household members were colonized with either MRSA or MSSA. There is no association between household density (number of co-residents) and type of infection (MRSA/MSSA) (Fisher’s p-values=0.171 and 0.371, respectively). In households of participants with MSSA wound infections, the number of colonized sites is positively associated with the level of household MSSA contamination (p=0.027). Further analyses will examine the associations between molecular subtypes, wound location, household surface contamination and household member colonization and infection. DISCUSSION/SIGNIFICANCE OF IMPACT: This study aims to understand the patient-level and environmental-level factors associated with SSTI recurrence, surface contamination and household transmission, and to examine the interactions between bacterial genotypic and clinical/phenotypic factors on decontamination, decolonization, SSTI recurrence and household transmission. This study will evaluate the barriers and facilitators to implementation of home visits by CHWs in underserved populations, and aims to strengthen the evidence base for implementation of strategies to identify and reduce household reservoirs and then control SSTI recurrence and household transmission.

2424

OBJECTIVES/SPECIFIC AIMS: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) skin and soft tissue infections (SSTIs) recurrence ranges from 16% to 43% and presents significant challenges to clinicians, patients, and families. The number of emergency department visits for SSTIs increased from 1993 to 2005 from 0.48 to 1.16 ED visits per 100 US residents (95% CI 0.94 to 1.39; p&lt;0.001); high safety-net status EDs saw a 4-fold increase in visits. The CA-MRSA Project (CAMP2) comparative effectiveness research (CER) study aims to evaluate a home-based intervention implemented by Community Health Workers (CHWs) or “promotoras” to prevent recurrence and transmission of CA-MRSA in primarily low-income, minority patients presenting to primary care with SSTIs. The intervention disseminates and implements methods found effective in the REDUCE MRSA trial. The present analysis was conducted using publically available data set to characterize the national patterns of healthcare utilization for treatment of SSTIs. METHODS/STUDY POPULATION: An analysis was conducted using data downloaded from the CDC National Ambulatory Medical Care Survey (NAMCS) and the CDC National Hospital Ambulatory Medical Care Survey (NHAMCS) from 2012 (most recent data available) to evaluate the addition of Emergency Departments (EDs) as compared to Ambulatory Care as recruitment sources for a clinical trial to reduce CA-MRSA SSTI recurrence and household transmission. “Low-income” population was defined using “Expected Source of Payment” categories “Medicaid” and “Uninsured,” and ICD-9-CM dermatologic diagnosis codes for SSTIs and ICD-9-CM Procedure Codes for Incision and Drainage (I&amp;D) were used to define a visit for SSTI treatment. RESULTS/ANTICIPATED RESULTS: In all patients, I&amp;D was performed at a higher rate in EDs as compared with the ambulatory care setting (49.57 vs. 1.44 per 10,000 US residents in Medicaid and Uninsured; 44.48 vs. 5.24 per 10,000 US residents in all other insurance types). Nationally, low-income patients are 4 times more likely to have I&amp;D procedure performed (OR 4.05, 95% CI 0.614–26.759, p&lt;0.0001) and 5 times more likely to be diagnosed with an SSTI (OR 5.10, 95% CI 2.987–8.707, p&lt;0.001) in the ED setting. DISCUSSION/SIGNIFICANCE OF IMPACT: These results confirm that low income patients seek primary care for SSTIs in both EDs and ambulatory care, such as Federally Qualified Health Centers (FQHCs). This also confirms the trend we have experienced in FQHCs in NYC, many of whom refer patients to the ED for the I&amp;D procedure, and those patients return to the FQHC for follow-up. Thus, the most comprehensive test of using CHWs to disseminate and implement the findings from the REDUCE MRSA trial would engage both EDs and Ambulatory Care/FQHCs for patient identification and recruitment.

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

Staphylococcus aureus colonization poses risk for subsequent skin and soft tissue infection (SSTI). We hypothesized that including systemic antibiotics in the management of S. aureus SSTI, in conjunction with incision and drainage, would reduce S. aureus colonization and incidence of recurrent infection. We prospectively evaluated 383 children with S. aureus SSTI requiring incision and drainage and S. aureus colonization in the anterior nares, axillae, or inguinal folds at baseline screening. Systemic antibiotic prescribing at the point of care was recorded. Repeat colonization sampling was performed within 3 months (median, 38 days; interquartile range, 22-50 days) in 357 participants. Incidence of recurrent infection was ascertained for up to 1 year. Participants prescribed guideline-recommended empiric antibiotics for purulent SSTI were less likely to remain colonized at follow-up sampling (adjusted hazard ratio [aHR], 0.49; 95% confidence interval [CI], .30-.79) and less likely to have recurrent SSTI (aHR, 0.57; 95% CI, .34-.94) than those not receiving guideline-recommended empiric antibiotics for their SSTI. Additionally, participants remaining colonized at repeat sampling were more likely to report a recurrent infection over 12 months (aHR, 2.37; 95% CI, 1.69-3.31). Clindamycin was more effective than trimethoprim-sulfamethoxazole (TMP-SMX) in eradicating S. aureus colonization (44% vs 57% remained colonized, P = .03) and preventing recurrent SSTI (31% vs 47% experienced recurrence, P = .008). Systemic antibiotics, as part of acute SSTI management, impact S. aureus colonization, contributing to a decreased incidence of recurrent SSTI. The mechanism by which clindamycin differentially affects colonization and recurrent SSTI compared to TMP-SMX warrants further study.

Genomic Characterization of USA300 Methicillin-Resistant Staphylococcus aureus (MRSA) to Evaluate Intraclass Transmission and Recurrence of Skin and Soft Tissue Infection (SSTI) Among High-Risk Military Trainees.

Military trainees are at increased risk for methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infection (SSTI). Whole genome sequencing (WGS) can refine our understanding of MRSA transmission and microevolution in congregate settings. We conducted a prospective case-control study of SSTI among US Army infantry trainees at Fort Benning, Georgia, from July 2012 to December 2014. We identified clusters of USA300 MRSA SSTI within select training classes and performed WGS on clinical isolates. We then linked genomic, phylogenetic, epidemiologic, and clinical data in order to evaluate intra- and interclass disease transmission. Furthermore, among cases of recurrent MRSA SSTI, we evaluated the intrahost relatedness of infecting strains. Nine training classes with ≥5 cases of USA300 MRSA SSTI were selected. Eighty USA300 MRSA clinical isolates from 74 trainees, 6 (8.1%) of whom had recurrent infection, were subjected to WGS. We identified 2719 single nucleotide variants (SNVs). The overall median (range) SNV difference between isolates was 173 (1-339). Intraclass median SNV differences ranged from 23 to 245. Two phylogenetic clusters were suggestive of interclass MRSA transmission. One of these clusters stemmed from 2 classes that were separated by a 13-month period but housed in the same barracks. Among trainees with recurrent MRSA SSTI, the intrahost median SNV difference was 7.5 (1-48). Application of WGS revealed intra- and interclass transmission of MRSA among military trainees. An interclass cluster between 2 noncontemporaneous classes suggests a long-term reservoir for MRSA in this setting.

Methicillin-Resistant Staphylococcus aureus: A Pharmacotherapy Primer

Methicillin-Resistant Staphylococcus aureus: A Pharmacotherapy Primer

Recurrent skin and soft tissue infections in HIV-infected patients during a 5-year period: incidence and risk factors in a retrospective cohort study.

BackgroundSkin and soft tissue infections (SSTIs) are common in the era of community-associated methicillin resistant Staphylococcus aureus among HIV-infected patients. Recurrent infections are frequent. Risk factors for recurrence after an initial SSTI have not been well-studied.MethodsRetrospective cohort study, single center, 2005–2009. Paper and electronic medical records were reviewed by one of several physicians. Subjects with initial SSTI were followed until the time of SSTI recurrence. Standard descriptive statistics were calculated to describe the characteristics of subjects who did and did not develop a recurrent SSTI. Kaplan-Meier methods were used to estimate the risk of recurrent SSTI. A Cox regression model was developed to identify predictors of SSTI recurrence.Results133 SSTIs occurred in 87 individuals. 85 subjects were followed after their initial SSTI, of whom 30 (35.3 %) had a recurrent SSTI in 118.3 person-years of follow-up, for an incidence of second SSTI of 253.6 SSTIs/1000 person-years (95 % CI 166.8-385.7). The 1-year Kaplan-Meier estimated risk of a second SSTI was 29.2 % (95 % CI 20.3–41.0 %), while the 3-year risk was 47.0 % (95 % CI 34.4–61.6 %). Risk factors for recurrent SSTI in a multivariable Cox regression model were non-hepatitis liver disease (HR 3.44; 95 % CI 1.02–11.5; p = 0.05), the presence of an intravenous catheter (HR 6.50; 95 % CI 1.47–28.7; p = 0.01), and a history of intravenous drug use (IVDU) (HR 2.80; 95 % CI 1.02-7.65; p = 0.05); African-American race was associated with decreased risk of recurrent SSTI (HR 0.12; 95 % CI 0.04-0.41; p < 0.01). Some evidence was present for HIV viral load ≥ 1000 copies/mL as an independent risk factor for recurrent SSTI (HR 2.21; 95 % CI 0.99-4.94; p = 0.05). Hemodialysis, currently taking HAART, CD4+ count, trimethoprim-sulfamethoxazole or azithromycin use, initial SSTI type, diabetes mellitus, incision and drainage of the original SSTI, or self-report of being a man who has sex with men were not associated with recurrence.ConclusionOf HIV-infected patients with an SSTI, nearly 1/3 had a recurrent SSTI within 1 year. Risk factors for recurrent SSTI were non-hepatitis liver disease, intravenous catheter presence, a history of IVDU, and non-African-American race. Low CD4+ count was not a significant risk factor for recurrence.

Where Does MRSA Live?

Source: Rodriguez M, Hogan GH, Burnham CA, et al. Molecular epidemiology of Staphylococcus aureus in households of children with community-associated S aureus skin and soft tissue infections. J Pediatrics. 2014; 164(1): 105– 111; doi: 10.1016/j.jpeds.2013.08.072Investigators from Washington University, St Louis, sought to determine if staphylococcal skin and soft tissue infections (SSTI) in children were acquired endogenously or from household members. Eligible patients (cases) were between 6 months and 20 years of age with a culture-confirmed methicillin-resistant Staphylococcus aureus (MRSA) or methicillin-susceptible S aureus (MSSA) SSTI and were also colonized with S aureus in the anterior nares, axillae, or inguinal folds. Molecular typing was done to compare colonizing and infecting isolates in children with S aureus SSTI and their household contacts.Baseline colonization status was assessed for household contacts and index cases. Only the index cases were assessed for colonization status at 1-, 3-, 6-, and 12-month follow-up visits. PCR testing was performed on isolates from household contacts and on infecting and colonizing isolates of the index case at baseline and on any colonizing isolates at the 4 follow-up visits.In all, 163 cases and 562 household contacts were studied. At baseline, 64% of cases were colonized with MRSA, 28% with MSSA, and 9% with both; 68% were colonized at a body site proximal to the infection site. MRSA was cultured from the SSTI in 81% and MSSA in 19% of the index cases. Of the 562 household contacts, 55% were colonized with S aureus: MRSA in 20%, MSSA in 33%, both in 2%. Contacts colonized with MRSA were significantly more likely to have had a SSTI in the past year compared to those not colonized with MRSA (36% vs 17%).There were 27 distinct strains of S aureus identified from all of the 1,299 S aureus isolates. At baseline, 67% of the infected children had at least 1 colonizing strain that matched the strain cultured from their infected site and in 46% there was concordance with a household contact. Of those index cases whose infecting strain did not match the colonizing strain (32%), 28% had at least 1 household contact with a colonizing strain that matched the infecting strain. Over the 12 months of study, index cases carried up to 6 distinct strain types and during this time, 72% were colonized with at least 1 strain that matched the baseline infecting strains.The authors conclude that one third of the children with SSTI were not colonized with the infecting strain, and among these children only about one quarter had a concordant strain in a household contact. This suggests that S aureus infections are acquired from both within and outside the household.Dr Crandall has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device.S aureus infections cause a broad range of clinical manifestations including SSTIs, bacteremia, and bone and joint infections. Historically MRSA was associated with hospital acquisition; however, community-associated MRSA (CA-MRSA) has emerged as a prevalent pathogen.1,2The epidemiology of SSTIs in the pediatric population is not completely understood but colonization with CA-MRSA is an established risk factor for acute infections.3 Strategies to prevent SSTI in children have focused on decolonizing the affected person and/or household with a regimen of intranasal antibiotic therapy in conjunction with antiseptic body washes. Although prophylactic decolonization is effective at decreasing S aureus carriage, it does not reduce the incidence of first-time SSTIs.4 Targeted decolonization of individuals with recurrent SSTIs and/or their household contacts, on the other hand, results in a modest reduction in recurrent SSTIs.5 However, it is unclear if removal of colonizing S aureus strains increases risk for acquisition of more virulent strains. Decolonization is currently only recommended in individuals and households with recurrent SSTI.6Overall, the results of this study indicate that a substantial number of SSTIs in children are caused by a strain of S aureus acquired outside the household. These results highlight the need for further investigation into the transmission of CA-MRSA in order to develop more effective strategies for disease prevention.While we await the unraveling of the mysteries of the ecology of MRSA, consider these measures which may decrease the household transmission: cessation of sharing personal items such as towels and washcloths, lotions, and bar soap, as well as the institution of dilute bleach baths (see AAP Grand Rounds, February 2012;27[2]:197).

Outbreak of Skin Infections Due to Panton-Valentine Leukocidin-Positive Methicillin-Susceptible Staphylococcus aureus in a French Prison in 2010-2011

Background. An outbreak of PVL-positive MSSA skin and soft tissue-infections (SSTIs) was suspected in May 2010 when recurrent SSTI was diagnosed in an inmate of a large prison in Nantes, France. Methods and findings. Retrospective and prospective investigations were performed. Microbiological characterisation was by DNA microarray testing (S. aureus genotyping - Identibac, Alere). We identified 14 inmates meeting our clinical and microbiological case definition for PVL-MSSA SSTI between March 2010 and April 2011. The SSTIs developed in tattooed areas in 4 patients and in areas shaved daily with a mechanical razor in 4 other patients. All case isolates exhibited a similar SmaI pulsed-field gel electrophoresis pattern. Microarray analysis showed that all 14 isolates harboured genes encoding PVL and enterotoxins (A, H, K, and Q) and belonged to clonal complex 1 (CC1). Individual and collective hygiene measures, education delivered to inmates and prison employees, and antibiotic treatment of SSTIs were successful in controlling the outbreak. No new cases were identified after April 2011. Routine screening for PVL-positive MSSA carriage was not feasible. Conclusions. Our data suggest that tattooing and shaving with mechanical razors may constitute risk factors for SSTIs among previously colonised inmates and contribute to the PVL-MSSA outbreak in the prison. Allowing inmates access to professional tattooists and to the hygiene and safety conditions available to people in the community would help to prevent tattoo-related infections.

Is there a relationship between hygiene practices and skin and soft tissue infections in diapered children?

The perineal and gluteal regions are the most frequent areas of skin and soft tissue infection (SSTI) in diapered children. No studies have investigated the relationship between perineal and general hygiene practices and SSTIs in this population. This study was conducted to evaluate this relationship. A cross-sectional observational study was conducted in an urban pediatric emergency department. Subjects were recruited into 3 study groups as follows: gluteal/perineal SSTIs (SSTI), diaper dermatitis (DD), or healthy normal skin (NS). Survey responses were analyzed for significance followed by a clinically oriented staged regression to model predictors of SSTI compared with the NS and DD groups. There were 100 subjects in the SSTI, 206 in the NS, and 151 in the DD groups. Race was the only demographic characteristic that differed between the groups. After adjustment for race, no day care attendance, history of SSTI, household contact with SSTI history, and higher propensity for diaper rash were associated with SSTI compared with NS. Regression results comparing SSTI to DD revealed no day care attendance, history of SSTI, household contact with SSTI history, less sensitive skin, and less diaper cream use to be predictors of SSTI. Perineal and general hygiene practices were not significantly different between children with SSTI compared with children with NS or DD. Based on the results of this study, further prospective studies should evaluate diaper hygiene practices that prevent DD and subsequent SSTIs, the preventative role of day care attendance, and effective interventions that minimize the risk of recurrent SSTIs.

Measurement and Impact of Staphylococcus aureus Colonization Pressure in Households

Methicillin-resistant Staphylococcus aureus (MRSA) "colonization pressure" (CP) predicts infections in hospitals. We applied the CP concept to staphylococcal transmission within households. We tested the hypothesis that children with S aureus skin and soft tissue infection (SSTI) plus colonization ("cases") with higher baseline household CP (HHCP) would be at greater risk for persistent colonization and recurrent SSTI during study period. We collected baseline colonization swabs from 92 cases and 296 of their household contacts. Cases underwent decolonization. S aureus HHCP was calculated as the proportion of colonized household contacts at baseline (excluding cases). S aureus colonization and recurrent SSTI in cases were followed for 12 months. Overall, median S aureus HHCP was 60% (mean = 55%). For cases colonized with MRSA, median MRSA HHCP was 11% (mean 29%); methicillin-susceptible S aureus (MSSA)-colonized cases had a median MSSA HHCP of 50% (mean = 49%). Over 1 year, MRSA HHCP was an independent risk factor for persistent MRSA colonization in cases (each 10-unit increase in HHCP associated with an adjusted odds ratio of 1.25; 95% confidence interval, 1.06-1.47). HHCP was not associated with recurrent SSTI in cases. MRSA HHCP is associated with persistent colonization in outpatients. Further studies are needed to determine the relationship between persistent colonization of household contacts, environmental contamination, and SSTI.

Clinical Pearls in Dermatology

Clinical Pearls in Dermatology

Household Versus Individual Approaches to Eradication of Community-Associated Staphylococcus aureus in Children: A Randomized Trial

Community-associated Staphylococcus aureus infections often affect multiple members of a household. We compared 2 approaches to S. aureus eradication: decolonizing the entire household versus decolonizing the index case alone. An open-label, randomized trial enrolled 183 pediatric patients (cases) with community-onset S. aureus skin abscesses and colonization of anterior nares, axillae, or inguinal folds from 2008 to 2009 at primary and tertiary centers. Participants were randomized to decolonization of the case alone (index group) or of all household members (household group). The 5-day regimen included hygiene education, twice-daily intranasal mupirocin, and daily chlorhexidine body washes. Colonization of cases and subsequent skin and soft tissue infection (SSTI) in cases and household contacts were ascertained at 1, 3, 6, and 12 months. Among 147 cases with 1-month colonization data, modified intention-to-treat analysis revealed S. aureus eradication in 50% of cases in the index group and 51% in the household group (P = 1.00). Among 126 cases completing 12-month follow-up, S. aureus was eradicated from 54% of the index group versus 66% of the household group (P = .28). Over 12 months, recurrent SSTI was reported in 72% of cases in the index group and 52% in the household group (P = .02). SSTI incidence in household contacts was significantly lower in the household versus index group during the first 6 months; this trend continued at 12 months. Household decolonization was not more effective than individual decolonization in eradicating community-associated S. aureus carriage from cases. However, household decolonization reduced the incidence of subsequent SSTI in cases and their household contacts. NCT00731783.