Epidemiology and Risk Factors for Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Among Burn Patients:

Nitric Oxide as an Efficient Antimicrobial Treatment for Second-Degree Burn Wounds

INTRODUCTION

Nitric oxide (NO) is a lipophilic gas with potent antimicrobial activity. Several in vitro and in vivo studies have demonstrated the broad-spectrum antimicrobial activity of NO-releasing compounds against bacteria, viruses, and parasites. The objective of this study was to assess the efficacy of topical NO formations with sustained release on microbial reduction in wounds.

MATERIALS AND METHODS

Swine was used as the preclinical animal model because of the similarities of porcine skin to human skin. Second-degree burn wounds were created in 3 pigs and then inoculated with Methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, or Candida albicans and covered with polyurethane film dressings to create biofilms. After 48 hours, wounds were then treated daily and then recovered for the bacterial burden assessments. Statistical analysis was performed using IBM SPSS statistics 27 using one-way ANOVA.

RESULTS

All treatments significantly reduced (P ≤ .05) the bacterial counts between assessment days 4 and 7. Wounds treated with the NVN4000 (1.8%) exhibited greater than 99.7% bacterial reduction on days 4 and 7. Significant differences (P ≤ .05) were observed in wounds treated with NVN4000 (1.8%) compared to silver sulfadiazine.

CONCLUSIONS

These studies demonstrate that topical NO-releasing formulations effectively reduce the microbial burden of several microorganisms and exhibit superior antimicrobial efficacy compared to silver sulfadiazine in the porcine wound model.

A 10-year retrospective study of methicillin-resistant Staphylococcus aureus from burn wound infection in southeast China from 2013 to 2022

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly encountered pathogens among burn patients incurring substantial morbidity and mortality. To investigate the epidemiology and features of MRSA in burn wound infections, we conducted a 10-year retrospective study on MRSA isolated from burn patients with burn wound infections from southeast China from 2013 to 2022.

Methods

One hundred MRSA isolates (10 isolates each year) from burn wound infection among burn patients from 2013 to 2022 were randomly selected and enrolled. In addition to the clinical data of the 100 burn patients, MRSA isolates were characterized by antimicrobial susceptibility testing, detection of toxin genes, and molecular typing.

Results

The median time from the onset of burns and admission to MRSA detected was 13 and 5 days, respectively. No MRSA isolate was found resistant to quinupristin/dalfopristin, linezolid, and vancomycin. Toxin gene seg was found most frequently (90%) followed by sea (70%) and eta (64%). CC8 (74%), ST239 (70%), and SCCmec III (72%) were the most common CC, ST, and SCCmec types, respectively.

Conclusion

ST239-III (70%) was the predominant clone found in MRSA from burn wound infection among burn patients in southeast China. ST239-III was less found from 2018 to 2022. A higher diversity of MRSA clones was observed in these recent 5 years than that from 2013 to 2017.

Molecular Characterization of Community-Associated Methicillin-Resistant Staphylococcus aureus in Iranian Burn Patients

Background & Objective:

Methicillin-resistant Staphylococcus aureus (MRSA) is reported as one of the important bacterial causes of burn wound infections. This study was carried out to investigate molecular characterization of community-associated MRSA (CA-MRSA) isolated from Iranian burn patients.

Methods:

A total of 31 isolates of S. aureus were collected from the Motahari Burns Hospital (Tehran, Iran) in 2016. All isolates were collected from outpatients and inpatients within 48 hours of admission. The mecA, pvl, tsst-1, hla-α, and psmα genes detecting, SCCmec, agr and PFGE typing were done.

Results:

A total of 13 (41.9%) isolates were cefoxitin-resistant and mecA-positive, which were considered as MRSA. The SCCmec typing MRSA strains revealed type II in 1 (7.7%), type III in 9 (69.2%), and other types in 3 isolates (23.7%) cases. The agr typing of all 31 isolates showed that 14 (45.2%), 1 (3.2%), 6 (19.4%), and 10 (32.3%) strains belonged to agr groups 1, 3, 4, and unknown type, respectively. The pvl, tsst-1, hla-α, and psmα genes were positive in 3 (9.7%), 4 (12.9%), 21 (67.7%), and 31 (100%) isolates, respectively. Considering the cut-off values of ≥50%, 3 groups of related isolates (cluster A1, B1, and C1) in PFGE study were observed.

Conclusion:

The MRSA strains of this study were initially isolated as Community-associated S. aureus (CA-MRSA); however molecular characterization showed that a significant proportion of them had hospital-associated MRSA (HA-MRSA) features. Therefore, it is likely that the HA-MRSA strains are spread among the community.

The relation between positive screening results and MRSA infections in burn patients

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) is a key pathogen in burn patients. Several factors put them at increased risk of MRSA infection: partial loss of the skin barrier, the immune-compromising effects of burns, prolonged hospital stays, and invasive procedures. This study aims to find the relation between MRSA screening swab cultures taken within 48 h of admission, weekly surveillance cultures, and MRSA infection secondary to colonization.

METHODS

The data of all burns patients admitted to the referral centre for burns from 2012 to 2016 were reviewed. MRSA cultures taken at admission and on weekly surveillance screening, including nasal, perianal, and wound swabs, were reviewed. To determine associations between MRSA colonization and infection rates, both MRSA-positive and MRSA-negative swab cultures were included in the analysis. Several risk factors were considered: age, gender, ethnicity, %TBSA, BAUX index, inhalational injury, ICU admission and days, need for ventilator support and days, length of stay (LOS) in hospital, and complications. Univariate and multiple logistic regression analyses were used to predict correlations between positive swab cultures and risk factors.

RESULTS

Data from 396 patients were reviewed. The median age at admission for the burn patients was 46 (IQR: 31-59) years. On admission, 2.5% of patients were MRSA positive, whereas 17.9% were found to be MRSA positive on weekly surveillance screening. At surveillance, 60.6% developed an infection secondary to MRSA colonization. An MRSA infection was not identified for any patient who did not have at least one positive admission or surveillance swab. A statistically significant association was found between any positive swab and MRSA infection (P < 0.001). The median number of complications reported in the MRSA-positive group was 2 (IQR: 1-3) versus 0 (IQR: 0-1) in the MRSA-negative group and the median length of hospital stay in the MRSA-positive group was 34.5 (IQR: 20.25-56.25) days versus 7 (IQR: 3-16) days in the MRSA-negative group (P < 0.001).

CONCLUSION

Nosocomial MRSA colonization rates are high, and patients incurring infections experience a greater than average LOS in hospital and complications. Over 60% of patients who had a positive swab culture at surveillance developed an infection, whereas, no patient with a negative MRSA swab status developed an infection. Hence, pragmatic prevention strategies have to be implemented.

MRSA colonization and acquisition in the burn unit: A systematic review and meta-analysis

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly encountered bacteria in the burn unit. In order to investigate the magnitude of this challenge, we assessed the prevalence of MRSA colonization on admission and the incidence of MRSA acquisition within burn units.

METHODS

We searched PubMed and EMBASE for studies reporting MRSA colonization among patients admitted in burn units.

RESULTS

We identified 16 articles that fulfilled our inclusion criteria and found an overall pooled prevalence of MRSA colonization upon the first 72 h of admission (colonization on admission) to the burn unit of 4.1% (95% CI: 2.7%-5.7%). MRSA acquisition in studies without a decolonization protocol was 21.2% (95% CI: 13.2%-30.5%) with a statistically significant downward trend over the years. Studies that implemented a decolonization protocol yielded a MRSA acquisition incidence rate of 4.5% (95% CI: 0.9%-10.6%). MRSA acquisition was higher among patients that have had inhalation injury (OR 3.96, 95% CI: 2.51-6.23), flame burns (OR 1.85, 95% CI: 1.25-2.73), or ICU admission (OR 3.12, 95% CI: 2.18-4.47).

CONCLUSION

Our study yielded that among burn victims, MRSA colonization prevalence on admission is not negligible and the risk of becoming MRSA colonized during hospitalization is higher when no decolonization protocols are implemented. Flame burns, admission to ICU, and inhalation injury were found to be associated with MRSA acquisition.

Hospital-associated methicillin-resistant Staphylococcus aureus: A cross-sectional analysis of risk factors in South African tertiary public hospitals

Introduction

Hospital-associated methicillin-resistant S. aureus (HA-MRSA) remains a significant cause of morbidity and mortality worldwide. We conducted a study to determine risk factors for HA-MRSA in order to inform control strategies in South Africa.

Methods

We used surveillance data collected from five tertiary hospitals in Gauteng and Western Cape provinces during 2014 for analysis. A case of HA-MRSA was defined as isolation of MRSA from a blood culture 48 hours after admission and/or if the patient was hospitalised in the six months prior to the current culture. Multivariable logistic regression modelling was used to determine risk factors for HA-MRSA.

Results

Of the 9971 patients with positive blood cultures, 7.7% (772) had S. aureus bacteraemia (SAB). The overall prevalence of MRSA among those with SAB was 30.9% (231/747; 95% confidence interval [CI] 27.6%– 34.3%). HA-MRSA infections accounted for 28.3% of patients with SAB (207/731; 95% CI 25.1%– 31.7%). Burns (adjusted odds ratio [aOR] 12.7; 95% CI 4.7–34.4), age ≤1 month (aOR 8.7; 95% CI 3.0–24.6), residency at a long-term care facility (aOR 5.2; 95% CI, 1.5–17.4), antibiotic use within two months of the current SAB episode (aOR 5.1; 95% CI 2.8–9.1), hospital stay of 13 days or more (aOR 2.8; 95% CI 1.3–5.6) and mechanical ventilation (aOR 2.2; 95% CI 1.07–4.6), were independent risk factors for HA-MRSA infection.

Conclusion

The prevalence of MRSA remains high in South African tertiary public hospitals. Several identified risk factors of HA-MRSA infections should be considered when instituting infection and prevention strategies in public-sector hospitals, including intensifying the implementation of antimicrobial stewardship programmes. There is an urgent need to strengthen infection prevention and control in burn wards, neonatal wards, and intensive care units which house mechanically ventilated patients.

Methicillin Resistant Staphylococcus aureus Transmission in a Ghanaian Burn Unit: The Importance of Active Surveillance in Resource-Limited Settings

Objectives:Staphylococcus aureus infections in burn patients can lead to serious complications and death. The frequency of S. aureus infection is high in low- and middle-income countries presumably due to limited resources, misuse of antibiotics and poor infection control. The objective of the present study was to apply population genomics to precisely define, for the first time, the transmission of antibiotic resistant S. aureus in a resource-limited setting in sub-Saharan Africa.

Methods:Staphylococcus aureus surveillance was performed amongst burn patients and healthcare workers during a 7-months survey within the burn unit of the Korle Bu Teaching Hospital in Ghana.

Results: Sixty-six S. aureus isolates (59 colonizing and 7 clinical) were obtained from 31 patients and 10 healthcare workers. Twenty-one of these isolates were ST250-IV methicillin-resistant S. aureus (MRSA). Notably, 25 (81%) of the 31 patients carried or were infected with S. aureus within 24 h of admission. Genome comparisons revealed six distinct S. aureus clones circulating in the burn unit, and demonstrated multiple transmission events between patients and healthcare workers. Further, the collected S. aureus isolates exhibited a wide range of genotypic resistances to antibiotics, including trimethoprim (21%), aminoglycosides (33%), oxacillin (33%), chloramphenicol (50%), tetracycline (59%) and fluoroquinolones (100%).

Conclusion: Population genomics uncovered multiple transmission events of S. aureus, especially MRSA, within the investigated burn unit. Our findings highlight lapses in infection control and prevention, and underscore the great importance of active surveillance to protect burn victims against multi-drug resistant pathogens in resource-limited settings.

Screening nasal swabs for methicillin resistant Staphylococcus aureus: A regional burn center's experience

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen that can result in substantial morbidity and mortality. Early detection of MRSA colonization by screening nasal swabs may be important in the management of burn-injured patients. However, studies examining its use in this population are limited. The aim of this study was to study the utility of admission MRSA screening nasal swabs and determine if being positive for MRSA on admission impacted outcomes.

MATERIALS AND METHODS

A retrospective review was conducted of burn patients who presented to a single regional burn center between June 2012 and December 2014. Electronic medical records and charts were reviewed for patient demographics and management. MRSA screening swabs were obtained from the anterior nares of burn patients upon admission. Patients without a MRSA nasal swab within 48h of admission were excluded. Outcomes analyzed included overall length of stay, ICU admission and length of stay, mechanical ventilation, procedure count, time to excision, and wound complications after normalizing to total body surface area burn size (%TBSA).

RESULTS

During the study period, 601 patients received a MRSA screening nasal swab upon admission. Of these, 24 patients screened positive for MRSA (4%). Patients who screened positive for MRSA had a significantly increased mean length of stay (3.95v 2.36 days; p<0.05) and number of surgical procedures (1.92v 1.06; p<0.05). Positively screened patients also had a higher proportion of wound infections (50% v 18.2%; p<0.05), half of which were caused by MRSA. Subsequent graft complications were seen in 50% of patients with a wound complication. Only 2 positively screened patients were started on empiric antibiotics.

CONCLUSIONS

Burn patients who screened positive for MRSA had greater lengths of stay, more surgical procedures, and higher wound complications. Early identification of MRSA colonized patients in this patient population might allow for treatment modifications that improve outcomes. Further study is warranted in a prospective clinical trial.

Universal decolonization with hypochlorous solution in a burn intensive care unit in a tertiary care community hospital

Infections are the leading cause of morbidity and mortality in burn patients. Patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) are at higher risk of developing an invasive infection, and MRSA is endemic in many burn units. The typical decolonization regimen of mupirocin and chlorhexidine bathing is not optimal in burn patients because of chlorhexidine limitations on nonintact skin. We studied the impact of universal decolonization using mupirocin and hypochlorous acid bathing on health care-associated MRSA infections in a burn intensive care unit. We show a significant decrease in total MRSA infections.

Microbiological findings in burn patients treated in a general versus a designated intensive care unit: Effect on length of stay

BACKGROUND

Infection is one of the most common causes of mortality and morbidity in burn patients. The incidence and frequency of microbiological micro-organisms are known to vary across different models of intensive care units. To date, no study has attempted to describe the different findings in burn patients treated in an open, general intensive care unit (GICU) versus a dedicated burns intensive care unit (BICU). Only limited data is available on the effect of these microbiological micro-organisms on patients' length of stay.

AIM

To characterize and compare the microbiological flora and antibiotic resistance patterns encountered in two different models of burn intensive care and to determine the effect of specific microbiological types on length of intensive care unit (ICU) and overall stay.

METHODS

A retrospective case-control study of 209 burn patients treated in two highly specialized, Western burn referral centres between September 2009 and March 2014.

RESULTS

9710 culture results were analysed, of which 2590 (26.7%) yielded positive results (1537 in the GICU and 1050 in the BICU). Gram-positive cultures were more frequently found in the GICU, whereas Gram-negative and yeast cultures were more prevalent in the BICU. The most frequently encountered micro-organisms in both units were similar and included Staphylococcus aureus, Pseudomonas aeruginosa, coagulase-negative staphylococci (CoNS) and Candida albicans. Significantly more resistant bacteria were detected in the BICU. Testing positive across all types of microbiological isolates, as well as for both Gram-positive and -negative bacteria significantly prolonged patient length of stay. This effect was even more pronounced if the micro-organisms were resistant to antimicrobial therapy.

CONCLUSION

There are notable differences in the microbiological isolate and antibiotic resistance patterns between burn patients treated in a GICU compared to a designated BICU. In both units, testing positive for resistant microbiological micro-organisms is significantly associated with longer hospital stay.

Prevalence of vancomycin resistant Staphylococcus aureus (VRSA) in methicillin resistant S. aureus (MRSA) strains isolated from burn wound infections

OBJECTIVES

The increase in resistance of methicillin resistant Staphylococcus aureus (MRSA) strains to vancomycin has been perceived as a formidable threat in the therapeutic fields. The present study investigated the vancomycin resistance traits of MRSA isolates [vancomycin resistant S. aureus (VRSA)] collected from burn patients.

MATERIALS AND METHODS

Twenty-nine of 40 isolates of Staphylococcus spp. were identified as S. aureus which were further tested against 20 commercially available antibiotics to determine antibiotic susceptibility patterns.

RESULTS

Imipenem was the most potential antibiotic resulting in 90% sensitivity, followed by netilmicin, clindamycin, and nitrofurantoin (80% sensitivity). All isolates were found to be resistant to penicillin. Approximately 75% of them were found to be resistant to methicillin, oxacillin, azithromycin, cipro-floxacin, and tetracycline. Approximately 45% isolates exhibited resistance to amikacin, chloramphenicol, gentamycin, and tobramycin. Twenty-one of the 29 strains of S. aureus were MRSA, of which 11 were resistant to vancomycin when employing the disc diffusion method. However, when the broth micro-dilution procedure was used to measure the minimum inhibitory concentration (MIC) of vancomycin, eight isolates were resistant to vancomycin, six with an MIC of 32 μg/mL and two with an MIC of 64 μg/mL.

CONCLUSION

A significant fraction of VRSA was found among MRSA strains in this study, revealing the necessity for new and effective drugs against MRSA.

Bacteriological cultures on admission of the burn patient: To do or not to do, that's the question

INTRODUCTION

In many burn centers, routine bacteriological swabs are taken from the nose, throat, perineum, and the burn wound on admission, to check for the presence of microorganisms that require specific measures in terms of isolation or initial treatment. According to the Dutch policy of "search and destroy," for example, patients infected by multiresistant bacteria have to be strictly isolated, and patients colonized with β-hemolytic Streptococcus pyogenes must receive antibiotic therapy to prevent failed primary closure or loss of skin grafts. In this respect, the role of bacteria cultured on admission in later infectious complications is investigated. The aim of this study is to assess systematic initial bacteriological surveillance, based on an extensive Dutch data collection.

MATERIALS AND METHODS

A total of 3271 patients primarily admitted to the Rotterdam Burn Centre between January 1987 and August 2010 with complete bacteriological swabs from nose, throat, perineum, and the burn wounds were included. For this study, microbiological surveillance was aimed at identifying resistant microorganisms such as methicillin-resistant Staphylococcus aureus (MRSA), multiresistant Acinetobacter, and multiresistant Pseudomonas, as well as Lancefield A β-hemolytic streptococci (HSA), in any surveillance culture. The cultures were labeled as "normal flora or non-suspicious" in the case of no growth or a typical low level of bacterial colonization in the nose, throat, and perineum and no overgrowth of one type of microorganism. Further, the blood cultures of 195 patients (6.0%) who became septic in a later phase were compared with cultures taken on admission to identify the role of the initially present microorganisms. Statistical analysis was performed using SPSS 20.0.

RESULTS

Almost 61% of the wound cultures are "non-suspicious" on admission. MRSA was cultured in 0.4% (14/3271) on admission; 12 out of these 14 patients (85.7%) were repatriated. Overall, 9.3% (12/129) of the repatriated patients were colonized with MRSA. Multiresistant Acinetobacter or Pseudomonas was detected in 0.3% (11/3271 and 10/3271, respectively). In total, 18 of the 129 repatriated patients (14%) had one or more resistant bacteria in cultures taken within the first 24h after admission in our burn center. On admission, S. pyogenes was found in 3.6% of patients (117/3271), predominantly in children up to 10 years of age (81/1065=7.6%).

CONCLUSIONS

Resistant bacteria or microorganisms that impede wound healing and cause major infections are found only in few bacteriological specimens obtained on admission of patients with burn wounds. However, the consequences in terms of isolation and therapy are of great importance, justifying the rationale of a systematic bacteriological surveillance on admission. Patients who have been hospitalized for several days in a hospital abroad and are repatriated show more colonization at admission in our burn center. The microorganisms identified are not only (multi)resistant bacteria, showing that a hospital environment can quickly become a source of contamination. These patients should receive special attention for resistant bacteria. HSA contamination is observed more frequently in younger children. Bacteria present at admission do not seem to play a predominant role in predicting later sepsis.

Risk factors for, and the effect of MRSA colonization on the clinical outcomes of severely burnt patients

BACKGROUND

MRSA is an on-going problem for burn patients.

AIM

To analyze risk factors for, and the effect of MRSA colonization on burn patients' outcome.

METHODS

During 21 months burn patients' details and MRSA isolates were analyzed, and a case-control study performed.

RESULTS

Of 357 burn patients, 57 (16%) tested positive for MRSA. Compared to the MRSA negative group, MRSA positive patients had a higher median total burn surface area (15%[IQR 5-17%] vs. 5%[IQR 2-8%]; p<0.001), more admissions to ICU (54% vs. 26%; p<0.001), longer ICU length of stay (4.3 vs. 1.0 days; p<0.001), required more operations (1.6 vs. 0.8; p<0.001), and had longer total hospital length of stay (25.5 vs. 8.0 days; p<0.001). MRSA positivity was a significant independent predictor of increased length of stay (6.0 days, 95%CI 2.39-9.6 days; p=0.001) in a multivariable regression model correcting for patients TBSA and co-morbidities. Cardiac comorbidities (OR 5.14, 95%CI 1.76-15.62; p<0.001) and a longer exposure to the hospital environment (OR 1.05, 95%CI 1.02-1.09, p=0.005) increased the likelihood for MRSA positivity.

CONCLUSION

The negative impact of MRSA positivity on burn patients outcome indicates the need for improved screening procedures for early identification and further efforts toward MRSA infection control to prevent cross-infection as this may significantly impair patients' outcome.

Hospital-acquired infections and thermally injured patients: chlorhexidine gluconate baths work

BACKGROUND

Thermally injured patients are at high risk for infections, including hospital acquired infections (HAIs). We modeled a twice-daily chlorhexidine gluconate (CHG) bath protocol aimed at decreasing HAIs.

METHODS

Bathing with a 0.9% CHG solution in sterile water was provided twice daily as part of routine care. Institutional HAI prevention bundles were in place and did not change during the study. Baseline HAI rates were collected for 12 months before the quality study implementation. Centers for Disease Control and Prevention definitions for HAIs were used; our blinded Infection Control physician made each determination. This was an Institutional Review Board-exempt protocol.

RESULTS

The study cohort included 203 patients before the quality trial and 277 patients after the quality trial. The median burn area was 25% of total body surface area. Baseline HAI rates were as follows: ventilator-associated pneumonia, 2.2 cases/1,000 ventilator-days; cathether-associated urinary tract infection, 2.7 cases/1,000 catheter-days; central line-associated bloodstream infection, 1.4 cases/1,000 device-days. With implementation of this protocol, the rates dropped to zero and have stayed at that level with the exception of 1 cathether-associated urinary tract infection. There were no untoward effects or observed delays in wound healing with this protocol. All of these changes were clinically significant, although not statistically significant; the study was not powered for statistical significance.

CONCLUSIONS

Using this nurse-driven protocol, we decreased, in a sustainable manner, the HAI rate in our intensive care unit to zero. No integumentary difficulties or wound healing delays were related to this protocol.

Antibiotic therapy for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) in non surgical wounds

BACKGROUND

Non surgical wounds include chronic ulcers (pressure or decubitus ulcers, venous ulcers, diabetic ulcers, ischaemic ulcers), burns and traumatic wounds. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) colonisation (i.e. presence of MRSA in the absence of clinical features of infection such as redness or pus discharge) or infection in chronic ulcers varies between 7% and 30%. MRSA colonisation or infection of non surgical wounds can result in MRSA bacteraemia (infection of the blood) which is associated with a 30-day mortality of about 28% to 38% and a one-year mortality of about 55%. People with non surgical wounds colonised or infected with MRSA may be reservoirs of MRSA, so it is important to treat them, however, we do not know the optimal antibiotic regimen to use in these cases.

OBJECTIVES

To compare the benefits (such as decreased mortality and improved quality of life) and harms (such as adverse events related to antibiotic use) of all antibiotic treatments in people with non surgical wounds with established colonisation or infection caused by MRSA.

SEARCH METHODS

We searched the following databases: The Cochrane Wounds Group Specialised Register (searched 13 March 2013); The Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 2); Database of Abstracts of Reviews of Effects (2013, Issue 2); NHS Economic Evaluation Database (2013, Issue 2); Ovid MEDLINE (1946 to February Week 4 2013); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, March 12, 2013); Ovid EMBASE (1974 to 2013 Week 10); EBSCO CINAHL (1982 to 8 March 2013).

SELECTION CRITERIA

We included only randomised controlled trials (RCTs) comparing antibiotic treatment with no antibiotic treatment or with another antibiotic regimen for the treatment of MRSA-infected non surgical wounds. We included all relevant RCTs in the analysis, irrespective of language, publication status, publication year, or sample size.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified the trials, and extracted data from the trial reports. We calculated the risk ratio (RR) with 95% confidence intervals (CI) for comparing the binary outcomes between the groups and planned to calculate the mean difference (MD) with 95% CI for comparing the continuous outcomes. We planned to perform the meta-analysis using both fixed-effect and random-effects models. We performed intention-to-treat analysis whenever possible.

MAIN RESULTS

We identified three trials that met the inclusion criteria for this review. In these, a total of 47 people with MRSA-positive diabetic foot infections were randomised to six different antibiotic regimens. While these trials included 925 people with multiple pathogens, they reported the information on outcomes for people with MRSA infections separately (MRSA prevalence: 5.1%). The only outcome reported for people with MRSA infection in these trials was the eradication of MRSA. The three trials did not report the review's primary outcomes (death and quality of life) and secondary outcomes (length of hospital stay, use of healthcare resources and time to complete wound healing). Two trials reported serious adverse events in people with infection due to any type of bacteria (i.e. not just MRSA infections), so the proportion of patients with serious adverse events was not available for MRSA-infected wounds. Overall, MRSA was eradicated in 31/47 (66%) of the people included in the three trials, but there were no significant differences in the proportion of people in whom MRSA was eradicated in any of the comparisons, as shown below.1. Daptomycin compared with vancomycin or semisynthetic penicillin: RR of MRSA eradication 1.13; 95% CI 0.56 to 2.25 (14 people).2. Ertapenem compared with piperacillin/tazobactam: RR of MRSA eradication 0.71; 95% CI 0.06 to 9.10 (10 people).3. Moxifloxacin compared with piperacillin/tazobactam followed by amoxycillin/clavulanate: RR of MRSA eradication 0.87; 95% CI 0.56 to 1.36 (23 people).

AUTHORS' CONCLUSIONS

We found no trials comparing the use of antibiotics with no antibiotic for treating MRSA-colonised non-surgical wounds and therefore can draw no conclusions for this population. In the trials that compared different antibiotics for treating MRSA-infected non surgical wounds, there was no evidence that any one antibiotic was better than the others. Further well-designed RCTs are necessary.

Novel application of a spatial frequency domain imaging system to determine signature spectral differences between infected and noninfected burn wounds

Complications of infection can increase burn-related morbidity and mortality. Early detection of burn wound infection could lead to more precise and effective treatment, reducing systemic complications and the need for long-term, broad-spectrum intravenous antibiotics. Quantitative cultures from biopsies are the accepted standard to determine infection. However, this methodology can take days to yield results and is invasive. This investigation focuses on the use of noninvasive imaging to determine the infection status of burn wounds in a controlled in vivo model. Full-thickness burn wounds were created on the dorsum of adult male rats (n = 6). Twenty-four hours after burn wound creation, wounds in the "Infected" group were inoculated with a vehicle containing 1 × 10(8) colony forming unit Staphylococcus aureus. "Control" group animals received vehicle alone. Subsequently, the wounds were imaged daily for a total of 10 days and the differences of skin optical properties were assessed using spatial frequency domain imaging at 16 different wavelengths from 500 to 700 nm. Regions of interest on the resulting images were selected and averaged at each time point. Statistically significant differences in average absorption and reduced scattering coefficients (μ(a) and μ(s)') at 620 and 700 nm were observed between the two groups (P < .05). Differential optical properties were most evident by day 4 and persisted throughout the time course. Differential signature changes in optical properties are evident in infected burn wounds. This novel application of spatial frequency domain imaging may prove to be a valuable adjunct to burn wound assessment. Further work will be aimed at determining dose-response relationships and prokaryotic species differences.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in a burn unit from Brazil

Methicillin-resistant Staphylococcus aureus (MRSA) poses a threat for patients in burn units. Studies that mix epidemiological designs with molecular typing may contribute to the development of strategies for MRSA control. We conducted a study including: molecular characterization of Staphylococcal Chromosome Cassette mecA (SCCmec), strain typing with pulsed field gel electrophoresis (PFGE) and detection of virulence genes, altogether with a case-case-control study that assessed risk factors for MRSA and for methicillin-susceptible S. aureus (MSSA), using S. aureus negative patients as controls. Strains were collected from clinical and surveillance cultures from October 2006 through March 2009. MRSA was isolated from 96 patients. Most isolates (94.8%) harbored SCCmec type III. SCCmec type IV was identified in isolates from four patients. In only one case it could be epidemiologically characterized as "community-associated". PFGE typing identified 36 coexisting MRSA clones. When compared to MSSA (38 isolates), MRSA isolates were more likely to harbor two virulence genes: tst and lukPV. Previous stay in other hospital and admission to Intensive Care Unit were independent risk factors for both MRSA and MSSA, while the number of burn wound excisions was significantly related with the former (OR=6.80, 95%CI=3.54-13.07). In conclusion, our study found polyclonal endemicity of MRSA in a burn unit, possibly related to importing of strains from other hospitals. Also, it pointed out to a role of surgical procedures in the dissemination of MRSA strains.

The epidemiology of methicillin-resistant Staphylococcus aureus on a burn trauma unit

OBJECTIVE

We assessed the frequency and relatedness of methicillin-resistant Staphylococcus aureus (MRSA) isolates to determine whether healthcare workers, the environment, or admitted patients could be a reservoir for MRSA on a burn trauma unit (BTU). We also assessed risk factors for MRSA colonization among BTU patients.

DESIGN

Prospective cohort study and surveillance for MRSA carriage.

SETTING

BTU of a Midwestern academic medical center.

PATIENTS AND PARTICIPANTS

Patients admitted to a BTU from February 2009 through January 2010 and healthcare workers on this unit during the same time period.

METHODS

Samples for MRSA culture were collected on admission from the nares and wounds of all BTU patients. We also had collected culture samples from the throat, axilla, antecubital fossa, groin, and perianal area of 12 patients per month. Samples collected from healthcare workers' nares and from environmental sites were cultured quarterly. MRSA isolates were typed by pulsed-field gel electrophoresis.

RESULTS

Of 144 patients, 24 (17%) carried MRSA in their nares on admission. Male sex (odds ratio [OR], 5.51; 95% confidence interval [95% CI], 1.25-24.30), admission for necrotizing fasciitis (OR, 7.66; 95% CI, 1.64-35.81), and MRSA colonization of a site other than the nares (OR, 23.40; 95% CI, 6.93-79.01) were independent predictors of MRSA nasal carriage. Cultures of samples collected from 4 healthcare workers and 4 environmental cultures had positive results. Two patients were colonized with strains that were indistinguishable from strains collected from a healthcare worker or the environment.

CONCLUSIONS

Patients were a major reservoir for MRSA. Infection control efforts should focus on preventing transmission of MRSA from patients who are MRSA carriers to other patients on the unit.

The prevalence of genes encoding leukocidins in Staphylococcus aureus strains resistant and sensitive to methicillin isolated from burn patients in Taleghani Hospital, Ahvaz, Iran

BACKGROUND

Staphylococcus aureus has been recognized as an important human pathogen and is the major cause of nosocomial infections. Various strains of S. aureus produce bicomponent toxins such as LukE/D, and PVL. The toxins subunits bind to leukocyte cell membrane inducing trans-membrane pore formation and subsequent cell lysis. PVL is an example of these toxins and causes leukocyte destruction and tissue necrosis. It seems that S. aureus strains comprising LukE/D and PVL genes are more important in the disease process and associated with severe skin diseases, fatal pneumonia and osteomyelitis with high morbidity and mortality.

OBJECTIVE

The aim of this study was to determine the prevalence of genes encoding leukocidins in S. aureus strains resistant and sensitive to methicillin isolated from burn patients in Taleghani hospital, Ahvaz, Iran.

METHODS

In an 11-month study, 203 staphylococci isolates were collected from burn patients. The isolates were examined by traditional culture method for detecting S. aureus strains and further confirmation with standard biochemical tests including catalase, coagulase and DNase. DNA was extracted from bacterial colony by simple boiling method. Using template DNA, the polymerase chain reaction technique (PCR) was used to detect mecA gene for detecting methicillin resistant S. aureus strains (MRSA), PVL and Luk-E/D genes.

RESULTS

Ninety-five (46.8%) out of total tested isolates were identified as S. aureus. Based on the results from PCR, 83 strains (87.36%), were mecA positive, so they were resistant to methicillin and the rest were sensitive to methicillin (MSSA). The prevalence of PVL and LukE/D genes in MRSA strains were (7.23%) and (66.26%) respectively. While this prevalence were (33.3%) for both genes in MSSA strains.

CONCLUSION

There were PVL and LukE/D positive MRSA isolates with high prevalence in evaluated hospital. Since resulting diseases from these bacteria are severe and may even lead to death, the prevention of disease progress is desired by early diagnosis and proper treatment.