Trimethoprim-Sulfamethoxazole Therapy Reduces Failure and Recurrence in Methicillin-Resistant Staphylococcus aureus Skin Abscesses after Surgical Drainage

''Myth Busting in Infectious Diseases'': A Comprehensive Review

Antibiotics have played a pivotal role in modern medicine, drastically reducing mortality rates associated with bacterial infections. Despite their significant contributions, the emergence of antibiotic resistance has become a formidable challenge, necessitating a re-evaluation of antibiotic use practices. The widespread belief in clinical practice that bactericidal antibiotics are inherently superior to bacteriostatic ones lacks consistent support from evidence in randomized controlled trials (RCTs). With the latest evidence, certain infections have demonstrated equal or even superior efficacy with bacteriostatic agents. Furthermore, within clinical practice, there is a tendency to indiscriminately order urine cultures for febrile patients, even in cases where alternative etiologies might be present. Consequently, upon obtaining a positive urine culture result, patients often receive antimicrobial prescriptions despite the absence of clinical indications warranting such treatment. Furthermore, it is a prevailing notion among physicians that extended durations of antibiotic therapy confer potential benefits and mitigate the emergence of antimicrobial resistance. Contrary to this belief, empirical evidence refutes such assertions. This article aims to address common myths and misconceptions within the field of infectious diseases.

Repurposing antibiotic resistance surveillance data to support treatment of recurrent infections in a remote setting

In northern Australia, a region with limited access to healthcare and a substantial population living remotely, antibiotic resistance adds to the complexity of treating infections. Focussing on Escherichia coli urinary tract infections (UTIs) and Staphylococcus aureus skin & soft tissue infections (SSTIs) captured by a northern Australian antibiotic resistance surveillance system, we used logistic regression to investigate predictors of a subsequent resistant isolate during the same infection episode. We also investigated predictors of recurrent infection. Our analysis included 98,651 E. coli isolates and 121,755 S. aureus isolates from 70,851 patients between January 2007 and June 2020. Following an initially susceptible E. coli UTI, subsequent recovery of a cefazolin (8%) or ampicillin (13%) -resistant isolate during the same infection episode was more common than a ceftriaxone-resistant isolate (2%). For an initially susceptible S. aureus SSTI, subsequent recovery of a methicillin-resistant isolate (8%) was more common than a trimethoprim-sulfamethoxazole-resistant isolate (2%). For UTIs and SSTIs, prior infection with a resistant pathogen was a strong predictor of both recurrent infection and resistance in future infection episodes. This multi-centre study demonstrates an association between antibiotic resistance and an increased likelihood of recurrent infection. Particularly in remote areas, a patient's past antibiograms should guide current treatment choices since recurrent infection will most likely be at least as resistant as previous infection episodes. Using population-level surveillance data in this way can also help clinicians decide if they should switch antibiotics for patients with ongoing symptoms, while waiting for diagnostic results.

Therapeutic Options and Outcomes for the Treatment of Children with Gram-Positive Bacteria with Resistances of Concern: A Systematic Review

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative Staphylococci (MR-CoNS), and vancomycin-resistant Enterococci (VRE) are increasing worldwide and represent a threat for the limited treatment options in pediatric patients and neonates compared to adults. Recommendations in pediatrics are mainly extrapolated from adults' studies.

METHODS

A literature search for the treatment of these pathogens in children (<18 years old) was conducted in Embase, MEDLINE, and Cochrane Library. Studies reporting data on single-patient-level outcomes related to a specific antibiotic treatment for multidrug resistant (MDR) Gram-positive bacterial infection in children were included. Studies reporting data from adults and children were included if single-pediatric-level information could be identified (PROSPERO registration: CRD42022383867).

RESULTS

The search identified 11,740 studies (since January 2000), of which 48 fulfilled both the inclusion and the exclusion criteria and were included in the analysis: 29 for MRSA, 20 for VRE, and seven for MR-CoNS. Most studies were retrospective studies. Vancomycin was mainly used as a comparator, while linezolid and daptomycin were the most studied antimicrobials showing good efficacy.

CONCLUSIONS

Linezolid showed a safety and efficacy profile in a neonatal setting; daptomycin is increasingly used for MRSA, but the evidence is scarce for VRE.

Improving Duration of Antibiotics for Skin and Soft-tissue Infections in Pediatric Urgent Cares

BACKGROUND AND OBJECTIVES

National guidelines recommend a 5- to 7-day course of antibiotics for most skin and soft-tissue infections (SSTIs). Our aim was to increase the percentage of pediatric patients receiving 5 to 7 days of oral antibiotics for SSTIs in our pediatric urgent care clinics (UCCs) from 60% to 75% by December 31, 2021.

METHODS

We performed cause-and-effect analysis and surveyed UCC providers to uncover reasons for hesitation with short antibiotic courses for SSTIs. Plan- Do-Study-Act (PDSA) cycle 1 provided an update on current guidelines for UCC providers and addressed providers' concerns. PDSA cycle 2 modified the electronic health record to display antimicrobial prescription sentences from shortest to longest duration. PDSA cycle 3 provided project outcome and balancing measure updates to UCC providers at regular intervals. We created a monthly report of patients 90 days and older in UCCs with a final diagnosis of SSTIs. We used a Shewhart control chart to identify special cause variations.

RESULTS

After completing our PDSA cycles, we found that the percentage of children receiving 5 to 7 days of oral antibiotics for SSTIs exceeded 85%. The improvement was sustained over multiple months. There was no increase in the proportion of patients returning to the UCCs with an SSTI diagnosis within 14 days.

CONCLUSIONS

By addressing primary drivers uncovered through quality improvement methodology, we shortened the antibiotic course for children seen in our UCCs with SSTIs. Outpatient antimicrobial stewardship programs may apply similar methods to other diagnoses to further improve duration of antibiotic prescriptions.

Optimizing Antibiotic Treatment of Skin Infections in Pediatric Emergency and Urgent Care Centers

OBJECTIVES

The objective was to optimize antibiotic choice and duration for uncomplicated skin/soft tissue infections (SSTIs) discharged from pediatric emergency departments (EDs) and urgent cares (UCs).

METHODS

Pediatric patients aged 0 to 18 years discharged from 3 pediatric EDs and 8 UCs with a diagnosis of uncomplicated SSTIs were included. Optimal treatment was defined as 5 days of cephalexin for nonpurulent SSTIs and 7 days of clindamycin or trimethoprim/sulfamethoxazole for purulent SSTIs. Exclusion criteria included erysipelas, folliculitis, felon, impetigo, lymphangitis, paronychia, perianal abscess, phlegmon, preseptal or orbital cellulitis, and cephalosporin allergy. Baseline data were collected from January 2018 to June 2019. Quality improvement (QI) interventions began July 2019 with a revised SSTI guideline, discharge order set, and maintenance of certification (MOC) QI project. MOC participants received 3 education sessions, monthly group feedback, and individual scorecards. Balancing measures included return visits within 10 days requiring escalation of care. Data were monitored through March 2021.

RESULTS

In total, 9306 SSTIs were included. The MOC QI project included 50 ED and UC physicians (27% of eligible physicians). For purulent SSTI, optimal antibiotic choice, plus duration, increased from a baseline median of 28% to 64%. For nonpurulent SSTI, optimal antibiotic choice, plus duration, increased from a median of 2% to 43%. MOC participants had greater improvement than non-MOC providers (P < .010). Return visits did not significantly change pre- to postintervention, remaining <2%.

CONCLUSIONS

We improved optimal choice and reduced duration of antibiotic treatment of outpatient SSTIs. MOC participation was associated with greater improvement and was sustained after the intervention period.

Management and Prevention of Staphylococcus aureus Infections in Children

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

Molecular analysis of an increase in trimethoprim/sulfamethoxazole-resistant MRSA reveals multiple introductions into a tertiary care hospital, Germany 2012-19

OBJECTIVES

Increasing spread of resistance could jeopardize the use of antifolates against MRSA infections.

METHODS

We compared the prevalence of phenotypic trimethoprim/sulfamethoxazole resistance in 20 534 clinical Staphylococcus aureus isolates (19 096 MSSA and 1438 MRSA) of non-redundant patients at Heidelberg University Hospital over 8 years and performed WGS on trimethoprim/sulfamethoxazole-resistant MRSA.

RESULTS

From 2012 to 2019, trimethoprim/sulfamethoxazole resistance in MSSA (674/19 096; 3.5%) ranged between 1.5% and 7.2% and in MRSA (135/1438; 9.4%) between 0.5% and 20.2%, reaching a peak in 2016 and 2018, respectively (Ptrend < 0.001). Trimethoprim/sulfamethoxazole resistance was more likely in outpatients than inpatients (P = 0.005), younger patients (P < 0.001), skin and soft tissue infections (SSTIs) (MRSA only, P = 0.05), submissions from pulmonology (MRSA only, P = 0.001), the upper respiratory tract (MSSA only, P < 0.001) and general surgery (MSSA only, P = 0.001). WGS of 76 trimethoprim/sulfamethoxazole-resistant MRSA revealed that 59% belonged to major pandemic CA-MRSA clones (ST22, ST8, ST398, ST772, ST30), 47% harboured Panton-Valentine leucocidin (PVL), 97% SCCmec IV/V, 71% dfrG and 28% dfrA. SNP-based phylogeny of trimethoprim/sulfamethoxazole-resistant MRSA core genomes favoured independent introduction over clonal expansion as the source, most prominently of dfrA+ trimethoprim/sulfamethoxazole-resistant ST22 MRSA from the Gaza Strip.

CONCLUSIONS

The presented results support that trimethoprim/sulfamethoxazole-resistant S. aureus, formerly associated with SSTI from outpatients and S. aureus in the (sub)tropics, is on the rise in the temperate zone, potentially due to migration. Closer monitoring of trimethoprim/sulfamethoxazole resistance in S. aureus is recommended to safeguard the effectiveness of antifolate compounds.

Antibiotic Duration, but Not Abscess Size, Impacts Clinical Cure of Limited Skin and Soft Tissue Infection After Incision and Drainage

Antibiotics are frequently prescribed following incision and drainage of cutaneous abscesses. In subgroup analyses from a recent clinical trial, we observed higher likelihood of cure with antibiotic courses beyond 5 or 7 days (up to 10). Among this cohort, for abscesses ≤5 cm, size did not modify the antibiotic effect.

Treatment of methicillin-resistant Staphylococcus aureus (MRSA): updated guidelines from the UK

These evidence-based guidelines are an updated version of those issued in 2008. They have been produced following a review of the published literature (2007-18) pertaining to the treatment of infections caused by MRSA. The guidelines update, where appropriate, previous recommendations, taking into account changes in the UK epidemiology of MRSA, ongoing national surveillance data and the efficacy of novel anti-staphylococcal agents licensed for use in the UK. Emerging therapies that have not been licensed for use in the UK at the time of the review have also been assessed.

Staphylococcal Skin and Soft Tissue Infections

Staphylococcus aureus is the most common bacteria causing purulent skin and soft tissue infections. Many disease-causing S aureus strains are methicillin resistant; thus, empiric therapy should be given to cover methicillin-resistant S aureus. Bacterial wound cultures are important for characterizing local susceptibility patterns. Definitive antibiotic therapy is warranted, although there are no compelling data demonstrating superiority of any one antibiotic over another. Antibiotic choice is predicated by the infection severity, local susceptibility patterns, and drug-related safety, tolerability, and cost. Response to therapy is expected within the first days; 5 to 7 days of therapy is typically adequate to achieve cure.

Therapeutic Effect of Topical Negative Pressure Therapy/Vacuum-Associated Closure Therapy on Cephalic Facial Skin Abscess

Objective: To evaluate the efficacy and safety of topical negative pressure therapy/vacuum-associated closure (TPN/VAC) in the treatment of cephalic facial skin abscess with infection. Methods: Forty-seven patients with cephalic facial skin abscesses were divided into two groups. The observation group was treated with negative pressure sealing drainage technique and primary wound suture. The control group was treated with abscess incision and drainage first; the second stage was wound suture after three to five days. The time and times of wound dressing, the pain score during wound dressing, the time of antibiotic use, and the recurrence rate were observed. Results: The wound healing time of the observation group was seven days, which was better than that of the control group for 10-12 days. The time of dressing change in the observation group was 14.9 ± 2.0 minutes (11-19 minutes), and the time of dressing change in the control group was 14.6 ± 2.6 minutes (10-20 minutes). There was no difference between the two groups (p > 0.05). The total number of dressing changes per patient in the observation group was three to five times, and the total number of dressing changes per patient in the observation group was five to eight times. There was a statistically significant difference between the two groups (p < 0.05). The pain score of the observation group was 3.2 ± 0.6 points (2-4 points), and the pain score of the control group was 5.1 ± 0.8 points (4-7 points). The difference between the two groups was statistically significant (p < 0.05). There was no recurrence in the observation group and two cases in the control group. Conclusion: Local negative pressure closed drainage technology can shorten the patient's healing course and reduce the duration of treatment, reduce the pain of dressing changes, improve prognosis, and have satisfactory therapeutic effect. It is a simple, effective, and safe technology, which is worthy of clinical application.

Decreasing the Duration of Discharge Antibiotic Treatment Following Inpatient Skin and Soft Tissue Abscess Drainage

Supplemental Digital Content is available in the text.

Introduction:

Skin and soft tissue abscesses do not require prolonged systemic antimicrobial treatment following drainage. We aimed to decrease the duration of discharge antibiotic treatment to less than 5 days following inpatient incision and drainage of uncomplicated abscesses.

Methods:

A new treatment protocol that defined uncomplicated abscesses, as well as inclusion and exclusion criteria, was created to monitor the accurate duration of prescribed therapy at discharge. We implemented a treatment algorithm that takes into account the epidemiologic changes in microbial etiologies and the presence of systemic findings for patients after surgical incision and drainage. We used control charts to assess the impact of the interventions.

Results:

Four hundred and eighteen patients were discharged following abscess drainage from our inpatient infectious diseases unit in 2016. The patients were 3 months to 21 years of age. Only 72 (17%) patients had prescribed discharge antibiotic treatment courses that were less than 5 days [range 0–31 days, median 8 days (IQR 6, 9)], and the average prescribed course at discharge was 8.6 days. During the study period, we significantly decreased the average duration of discharge antibiotics to 7.3 days in all patients (P = 0.0016, 95% CI: −2.1036 to −0.4964, difference of means −1.3). The discharge treatment duration of patients with uncomplicated abscess was shorter at 4.7 days [range 0–9 days, median 5 days, (IQR 3, 5)]. Prescription compliance to less than 5 days treatment course at discharge increased from the baseline of 17% to 42% overall.

Conclusions:

Standardizing definitions of uncomplicated skin and soft tissue abscesses was critical to the success of this project. In addition to possible improved treatment adherence and decreased side effects, our protocol led to decreased patient care costs with no documented changes in readmission rates.

Common Community-acquired Bacterial Skin and Soft-tissue Infections in Children: an Intersociety Consensus on Impetigo, Abscess, and Cellulitis Treatment

PURPOSE

The main objective of this article was to offer practical suggestions, given the existing evidence, for identifying and managing bacterial impetigo, abscess, and cellulitis in ambulatory and hospital settings.

METHODS

Five Italian pediatric societies appointed a core working group. In selected conditions, specially trained personnel evaluated quality assessment of treatment strategies according to the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Only randomized controlled trials (RCTs) and observational studies were included for quality assessment according to the GRADE methodology. MEDLINE, Ovid MEDLINE, EMBASE, and Cochrane Library databases were searched with a strategy combining MeSH and free text terms.

FINDINGS

The literature review included 364 articles focusing on impetigo, skin abscess, and cellulitis/orbital cellulitis. The articles included for quality assessment according to the GRADE methodology for impetigo comprised 5 RCTs and 1 observational study; for skin abscess, 10 RCTs and 3 observational studies were included; for cellulitis and erysipelas, 5 RCTs and 5 observational studies were included; and for orbital cellulitis, 8 observational studies were included. Recommendations were formulated according to 4 grades of strength for each specific topic (impetigo, skin abscesses, cellulitis, and orbital cellulitis). Where controversies arose and expert opinion was considered fundamental due to lack of evidence, agreement according to Delphi consensus recommendations was included.

IMPLICATIONS

Based on a literature review and on local epidemiology, this article offers practical suggestions for use in both ambulatory and hospital settings for managing the most common bacterial SSTIs.

Prospective observational study to assess the need for postoperative antibiotics following surgical incision and drainage of skin and soft tissue abscess in pediatric patients

BACKGROUND

Post-operative antibiotics are often utilized for skin and soft tissue infection (SSTI) requiring surgical incision and drainage (I&D). We propose that antibiotics are unnecessary following I&D.

METHODS

Patients aged 3months to 6years with SSTI of the buttocks, groin, thigh, and/or labia requiring I&D were prospectively enrolled. The primary outcome was the proportion of patients requiring re-drainage and/or antibiotics for SSTI recurrence, within 30days. Follow-up consisted of a 30-day phone call, with optional 2-week office visit, combined with chart review for patients lost to follow-up. A one-sample binomial proportion with 95% confidence interval (CI) was used to examine non-inferiority for rate of treatment success, using previously published success rates for patients receiving antibiotics post-operatively (95.9%, with a 7% margin of equivalence).

RESULTS

A total of 92 patients were enrolled. All patients received pre-operative antibiotics. There was one treatment failure (success rate 0.989, CI 0.941-0.999). The recurrence rate was noninferior to previously-published data for patients receiving postoperative antibiotics (p<0.001). Subgroup analysis of patients who completed 30-day follow-up yielded a success rate of 0.973, CI 0.858-0.999 and evidence of non-inferiority (p=0.04).

CONCLUSIONS

Post-operative management excluding antibiotics should be considered for patients who undergo I&D for SSTI.

LEVEL OF EVIDENCE

Level II (prospective cohort study with <80% follow-up).

Outpatient antimicrobial stewardship targets for treatment of skin and soft-tissue infections

OBJECTIVE

We sought to identify factors associated with long duration and/or non-first-line choice of treatment for pediatric skin and soft-tissue infections (SSTIs).

DESIGN

Retrospective cohort study.

SETTING

Ambulatory encounter claims of Medicaid-insured children lacking chronic medical conditions treated for SSTI and/or animal bite injury in Ohio in 2014.

METHODS

For all diagnoses, long treatment duration was defined as treatment >7 days. Non-first-line choice of treatment for SSTI included treatment with 2 antimicrobials dispensed on the same calendar day or any treatment not listed in the Infectious Diseases Society of America guidelines. The adjusted odds of (1) long treatment duration and (2) non-first-line choice of treatment were calculated for patient age, prescriber type, and patient county of residence characteristics (ie, rural vs metropolitan area and poverty rate).

RESULTS

Of 10,310 encounters with complete data available, long treatment duration was prescribed in 7,968 (77.3%). The most common duration of treatment prescribed was 10 days. A non-first-line choice was prescribed in 1,030 encounters (10%). Dispensation of 2 antimicrobials on the same calendar day was the most common reason for the non-first-line choice, and of these, trimethoprim-sulfamethoxazole plus a first-generation cephalosporin was the most common regimen. Compared to pediatricians, the adjusted odds ratio of long treatment duration was significantly lower for all other primary care specialties. Conversely, nonpediatricians were more likely to prescribe a non-first-line treatment choice. Patient residence in a high-poverty county increased the odds of both long duration and non-first-line choice of treatment.

CONCLUSIONS

Healthcare claims may be utilized to measure opportunities for first-line choice and/or shorter duration of treatment for SSTI.

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

Background

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

Methods

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

Results

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

Conclusions

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

Ultrasound-Guided Drainage for Pediatric Soft Tissue Abscesses Decreases Clinical Failure Rates Compared to Drainage Without Ultrasound: A Retrospective Study

OBJECTIVES

Soft tissue abscesses are common in the pediatric emergency department (ED). Ultrasound (US) can be used to both diagnose soft tissue abscesses as well as guide drainage. We hypothesized that clinical failure rates would be less in pediatric patients with suspected skin abscesses when evaluated with US.

METHODS

We performed a retrospective review of suspected pediatric skin abscesses at 4 EDs over a 22-month period. Cases were identified through electronic medical record descriptions, discharge diagnoses, and US database records. Data on US use, findings, and outcomes were abstracted to an electronic database. Comparisons between groups included US versus non-US (primary outcome) as well as surgical drainage vs nonsurgical drainage (secondary outcome).

RESULTS

A total of 377 patients were seen with concern for a potential skin abscess; 141 patients (37.4%) underwent US imaging during their visit, and 239 (63.4%) underwent incision and drainage (I&D) during their ED stay: 90 with US and 149 without. The failure rate for patients evaluated with US was significantly lower than that for those evaluated without US (4.4% versus 15.6%; P < .005). Thirty-four (11.3%) of the 302 patients with a diagnosis of an abscess failed therapy: 19 (8.2%) after I&D and 15 (21.1%) after nonsurgical management. Failure after I&D was associated with a smaller abscess cavity on US imaging (17.2 versus 44.8 mm³ ; P < .05).

CONCLUSIONS

The use of US for patients with a suspected skin abscess was associated with a reduction in the amount of clinical failure rates after both surgical drainage and nonsurgical therapy. Ultrasound should be used when evaluating or treating patients with abscesses.

Multidrug and Mupirocin Resistance in Environmental Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates from Homes of People Diagnosed with Community-Onset MRSA Infection

Patients with community-onset (CO) methicillin-resistant Staphylococcus aureus (MRSA) infections contribute to MRSA contamination of the home environment and may be reexposed to MRSA strains from this reservoir. This study evaluates One Health risk factors, which focus on the relationship between humans, animals, and the environment, for the increased prevalence of multiple antimicrobial-resistant MRSA isolates in the home environment. During a trial of patients with CO-MRSA infection, MRSA was isolated from the household environment at the baseline and 3 months later, following randomization of patients and household members to mupirocin-based decolonization therapy or an education control group. Up to two environmental MRSA isolates collected at each visit were tested. MRSA isolates were identified in 68% (65/95) of homes at the baseline (n = 104 isolates) and 51% (33/65) of homes 3 months later (n = 56 isolates). The rates of multidrug resistance (MDR) were 61% among isolates collected at the baseline and 55% among isolates collected at the visit 3 months later. At the baseline, 100% (14/14) of MRSA isolates from rural homes were MDR. While antimicrobial use by humans or pets was associated with an increased risk for the isolation of MDR MRSA from the environment, clindamycin use was not associated with an increased risk for the isolation of MDR MRSA. Incident low-level mupirocin-resistant MRSA strains were isolated at 3 months from 2 (5%) of 39 homes that were randomized to mupirocin treatment but none of the control homes. Among patients recently treated for a CO-MRSA infection, MRSA and MDR MRSA were common contaminants in the home environment. This study contributes to evidence that occupant use of antimicrobial drugs, except for clindamycin, is associated with MDR MRSA in the home environmental reservoir. (This study has been registered at ClinicalTrials.gov under registration no. NCT00966446.)IMPORTANCE MRSA is a common bacterial agent implicated in skin and soft tissue infections (SSTIs) in both community and health care settings. Patients with CO-MRSA infections contribute to environmental MRSA contamination in these settings and may be reexposed to MRSA strains from these reservoirs. People interact with natural and built environments; therefore, understanding the relationships between humans and animals as well as the characteristics of environmental reservoirs is important to advance strategies to combat antimicrobial resistance. Household interactions may influence the frequency and duration of exposure, which in turn may impact the duration of MRSA colonization or the probability for recurrent colonization and infection. Therefore, MRSA contamination of the home environment may contribute to human and animal recolonization and decolonization treatment failure. The aim of this study was to evaluate One Health risk factors that may be amenable to intervention and may influence the recovery of MDR and mupirocin resistance in CO-MRSA isolates.

Sulfamethoxazole-Trimethoprim (Cotrimoxazole) for Skin and Soft Tissue Infections Including Impetigo, Cellulitis, and Abscess

Skin and soft tissue infections (SSTI) affect millions of people globally, which represents a significant burden on ambulatory care and hospital settings. The role of sulfamethoxazole-trimethoprim (SXT) in SSTI treatment, particularly when group A Streptococcus (GAS) is involved, is controversial. We conducted a systematic review of clinical trials and observational studies that address the utility of SXT for SSTI treatment, caused by either GAS or Staphylococcus aureus, including methicillin-resistant (MRSA). We identified 196 studies, and 15 underwent full text review by 2 reviewers. Observational studies, which mainly focused on SSTI due to S aureus, supported the use of SXT when compared with clindamycin or β-lactams. Of 10 randomized controlled trials, 8 demonstrated the efficacy of SXT for SSTI treatment including conditions involving GAS. These findings support SXT use for treatment of impetigo and purulent cellulitis (without an additional β-lactam agent) and abscess and wound infection. For nonpurulent cellulitis, β-lactams remain the treatment of choice.

A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses

BACKGROUND

Uncomplicated skin abscesses are common, yet the appropriate management of the condition in the era of community-associated methicillin-resistant Staphylococcus aureus (MRSA) is unclear.

METHODS

We conducted a multicenter, prospective, double-blind trial involving outpatient adults and children. Patients were stratified according to the presence of a surgically drainable abscess, abscess size, the number of sites of skin infection, and the presence of nonpurulent cellulitis. Participants with a skin abscess 5 cm or smaller in diameter were enrolled. After abscess incision and drainage, participants were randomly assigned to receive clindamycin, trimethoprim-sulfamethoxazole (TMP-SMX), or placebo for 10 days. The primary outcome was clinical cure 7 to 10 days after the end of treatment.

RESULTS

We enrolled 786 participants: 505 (64.2%) were adults and 281 (35.8%) were children. A total of 448 (57.0%) of the participants were male. S. aureus was isolated from 527 participants (67.0%), and MRSA was isolated from 388 (49.4%). Ten days after therapy in the intention-to-treat population, the cure rate among participants in the clindamycin group was similar to that in the TMP-SMX group (221 of 266 participants [83.1%] and 215 of 263 participants [81.7%], respectively; P=0.73), and the cure rate in each active-treatment group was higher than that in the placebo group (177 of 257 participants [68.9%], P<0.001 for both comparisons). The results in the population of patients who could be evaluated were similar. This beneficial effect was restricted to participants with S. aureus infection. Among the participants who were initially cured, new infections at 1 month of follow-up were less common in the clindamycin group (15 of 221, 6.8%) than in the TMP-SMX group (29 of 215 [13.5%], P=0.03) or the placebo group (22 of 177 [12.4%], P=0.06). Adverse events were more frequent with clindamycin (58 of 265 [21.9%]) than with TMP-SMX (29 of 261 [11.1%]) or placebo (32 of 255 [12.5%]); all adverse events resolved without sequelae. One participant who received TMP-SMX had a hypersensitivity reaction.

CONCLUSIONS

As compared with incision and drainage alone, clindamycin or TMP-SMX in conjunction with incision and drainage improves short-term outcomes in patients who have a simple abscess. This benefit must be weighed against the known side-effect profile of these antimicrobials. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00730028 .).

Same-day discharge after incision and drainage of soft-tissue abscess in diaper-age children is safe and effective

PURPOSE

Many pediatric centers admit patients following incision and drainage (I&D) of soft-tissue abscesses. The purpose of this study is to assess the safety and efficacy of the same-day discharge following I&D.

METHODS

Retrospective review was performed of children aged 3 months-4 years who underwent operative I&D of an abscess followed by same-day discharge. Patients receiving antibiotics within 2 weeks of presentation were excluded. Treatment failure was defined as readmission or repeat procedure related to the initial abscess. Statistical analysis was performed using Wilcoxon Rank-Sum and Fisher's Exact tests.

RESULTS

There were 442 procedures performed in 408 patients. Mean age was 1.8 years. Fever was noted in 25.8%. Of those who had a white blood cell (WBC) count drawn, 59.7% had leukocytosis. Mean time from procedure to discharge was 2.3 h, and 85.0% were discharged with oral antibiotics. Treatment failure occurred in four (0.9%) and ten (2.3%) patients at 14 and 30 days, respectively. Mean WBC count was higher in the 14-day treatment failure group (24.1 versus 16.3; p = 0.10). In patients with leukocytosis, there were 2 (1.4%) treatment failures compared to none in those without leukocytosis.

CONCLUSION

Same-day discharge after I&D of abscess in diaper-age children is safe and effective.

Revival of old antibiotics: needs, the state of evidence and expectations

The gap between the emergence of antibiotic resistance and new antibiotic development has drawn attention to old antibiotics whose spectrum of coverage frequently comprises highly resistant bacteria. However, these antibiotics have frequently not undergone the structured process of antibiotic development of modern antibiotics, from pharmacokinetic/pharmacodynamic (PK/PD) studies establishing safe and effective dosing, establishment of susceptibility breakpoints, to clinical trials establishing clinical safety and effectiveness. In this review, we highlight the gaps for which we need old antibiotics in community- and hospital-acquired infections. Reviewing recently published and ongoing randomised controlled trials (RCTs) shows advances in our understanding of the efficacy and effectiveness of oral fosfomycin, mecillinam and nitrofurantoin for cystitis, and of trimethoprim/sulfamethoxazole for complicated skin infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in the community. Summarising older evidence shows the inferiority of chloramphenicol versus modern antibiotics for severe infections. We lack studies on severe infections caused by carbapenem-resistant Gram-negative bacteria and other multidrug-resistant (MDR) bacteria in hospitalised and critically ill patients; ongoing studies assessing colistin and intravenous fosfomycin might fill in some gaps. In the re-development process of old antibiotics, we mandate modern PK/PD studies comprising special populations as well as RCTs addressing the target population of patients in need of these antibiotics powered to examine patient-relevant outcomes. Structured antibiotic re-development from the laboratory to evidence-based treatment recommendations requires public funding, multidisciplinary collaboration, international co-ordination, and methods to streamline the recruitment of critically ill patients infected by MDR bacteria.