Methicillin-resistant Staphylococcus aureus in burns patients--why all the fuss?

Bloodstream infections and multidrug resistant bacteria acquisition among burns patients in Australia and New Zealand: A registry-based study

INTRODUCTION

This study interrogates infection related data in the Burns Registry of Australia and New Zealand (BRANZ), to examine associations of multi-drug resistant organisms (MDROs) and blood stream infection (BSI).

METHODS

Data between July 2016 and June 2021 were analysed to determine prevalence, risk factors and outcomes associated with BSIs and MDROs: Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), carbapenem-resistant Pseudomonas spp. (CRP), and carbapenem-resistant Enterobacter (CRE). Data completeness and value for quality improvement activity were assessed.

RESULTS

We found a low incidence (3.4%) of the resistant organisms of interest, and no change over the study period. Fequency varied between services and increased with age and size of burn. MRSA was the commonest organism in all age groups. A positive BSI result occurred in 1.6% of patients (12.1% of cultures taken) at a median time of 10.2 days post injury. Free text identification of organisms was inconsistently documented.

CONCLUSIONS

The low rate and patterns of acquisition of MDROs of interest and BSIs is comparable with reports from countries with low incidence of massive burns. Wider adoption of a standardized laboratory reporting framework would help realise the potential of clinical quality registries to provide data which supports evidence based infection prevention initiatives.

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.

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.

Colonization With Methicillin-Resistant Staphylococcus aureus in ICU Patients Morbidity, Mortality, and Glycopeptide Use

Objective:

To determine the impact of methicillin-resis-tant Staphylococcus aureus (MRSA) colonization on the occurrence of S aureus infections (methicillin-resistant and methicillin-suscep-tible), the use of glycopeptides, and outcome among intensive care unit (ICU) patients.

Design:

Prospective observational cohort survey.

Setting:

A medical-surgical ICU with 10 single-bed rooms in a 460-bed, tertiary-care, university-affiliated hospital.

Patients:

A total of 1,044 ICU patients were followed for the detection of MRSA colonization from July 1, 1995, to July, 1 1998.

Methods:

MRSA colonization was detected using nasal samples in all patients plus wound samples in surgical patients within 48 hours of admission or within the first 48 hours of ICU stay and weekly thereafter. MRSA infections were defined using Centers for Disease Control and Prevention standard definitions, except for ventilator-associated pneumonia and catheter-related infections, which were defined by quantitative distal culture samples.

Results:

One thousand forty-four patients (70% medical patients) were included in the analysis. Mean age was 61±18 years; mean Simplified Acute Physiologic Score (SAPS) II was 36.4±20; and median ICU stay was 4 (range, 1-193) days. Two hundred thirty-one patients (22%) died in the ICU. Fifty-four patients (5.1%) were colonized with MRSA on admission, and 52 (4.9%) of 1,044 acquired MRSA colonization in the ICU. Thirty-five patients developed a total of 42 S aureus infections (32 MRSA, 10 methi-cillin-susceptible). After factors associated with the development of an S aureus infection were adjusted for in a multivariate Cox model (SAPS II >36: hazard ratio [HR], 1.64; P=.09; male gender: HR, 2.2; P=.05), MRSA colonization increased the risk of S aureus infection (HR, 3.84; P=.0003). MRSA colonization did not influence ICU mortality (HR, 1.01; P=.94). Glycopeptides were used in 11.4% of the patients (119/1,044) for a median duration of 5 days. For patients with no colonization, MRSA colonization on admission, and ICU-acquired MRSA colonization, respectively, glycopeptide use per 1,000 hospital days was 37.7, 235.2, and 118.3 days. MRSA colonization per se increased by 3.3-fold the use of glycopeptides in MRSA-colonized patients, even when an MRSA infection was not demonstrated, compared to non-colonized patients.

Conclusions:

In our unit, MRSA colonization greatly increased the risk of S aureus infection and of glycopeptide use in colonized and non-colonized patients, without influencing ICU mortality. MRSA colonization influenced glycopeptide use even if an MRSA infection was not demonstrated; thus, an MRSA control program is warranted to decrease vancomycin use and to limit glycopeptide resistance in gram-positive cocci.

Comparison of the pharmacokinetics of linezolid in burn and non-burn rabbits

Linezolid is effective on many resistant organisms for the treatment of severe infections in burns. However, its pharmacokinetics was difficult to predict after major burns. The study aimed to describe the pharmacokinetic properties of linezolid administered intravenously at a dose of 10 mg/kg in severely burned rabbits in comparison to that in non-burns. Linezolid concentrations were quantitatively analyzed by high-performance liquid chromatography. The direct consequence of the physiological changes after burn injury was lower plasma linezolid concentrations. In addition, burn injury induced significantly altered pharmacokinetic parameters with higher inter-individual variability. The distribution volume and clearance rate were increased (2.88 vs. 1.92 L/kg, P > 0.05; 0.28 vs. 0.20 L/h/kg, P < 0.05), and the AUC0-∞ was significantly lower (37.99 vs. 51.47 mg/L h, P < 0.05). However, there were almost no changes in half-life and mean residence time. These results suggested that therapeutic drug monitoring and dosage individualization of linezolid in patients with severe burns were necessary.

The evaluation of nasal mupirocin to prevent Staphylococcus aureus burn wound colonization in routine clinical practice

BACKGROUND

Staphylococcus aureus wound colonization frequently occurs in patients with burns and can cause impaired wound healing. Nasal mupirocin application may contribute to the reduction of burn wound colonization of endogenous origin, whereas colonization by the exogenous route can be reduced by blocking cross-infection from other sources. In this study we evaluated whether the implementation of routine treatment of patients and burn center personnel using nasal mupirocin ointment reduces S. aureus burn wound colonization.

METHODS

We composed three study groups, consisting of a control period (Control), a mupirocin period (MUP), in which patients with burns were all receiving nasal mupirocin at admission, and a mupirocin+personnel period (MUP+P), in which we also screened the burn center personnel and decolonized S. aureus carriers by nasal mupirocin.

RESULTS

The patients who carried S. aureus in their nose and did not have S. aureus burn wound colonization at admission were considered as patients susceptible for the use of nasal mupirocin. In these patients, the S. aureus burn wound colonization rate was the same in all study groups. S. aureus nasal carriage was a significant independent risk factor for burn wound colonization (OR: 3.3; 95% CI: 1.4-7.6) when analyzed within the three study groups.

CONCLUSION

Although S. aureus carriage is a significant risk factor for developing burn wound colonization, the routine use of nasal mupirocin did not contribute to a reduction of burn wound colonization.

The role of nasal carriage in Staphylococcus aureus burn wound colonization

Thermal injury destroys the physical skin barrier that normally prevents invasion of microorganisms. This and concomitant depression of local and systemic host cellular and humoral immune responses are important factors that contribute to colonization and infection of the burn wound. One of the most common burn wound pathogens is Staphylococcus aureus. Staphylococcus aureus is both a human commensal and a frequent cause of infections leading to mild to life-threatening diseases. Despite a variety of infection control measures, for example patient cohorting and contact precaution at burn centres, S. aureus is still frequently encountered in burn wounds. Colonization with S. aureus has been associated with delayed wound healing, increased need for surgical interventions, and prolonged length of stay at burn centres. In this minireview, we focus on S. aureus nasal carriage in relation to S. aureus burn wound colonization and subsequent infection, and its impact on strategies for infection control.

Prevention of Staphylococcus aureus burn wound colonization by nasal mupirocin

BACKGROUND

There are two important routes for the transmission of Staphylococcus aureus to the burn wound. In the endogenous route, patients naturally carrying S. aureus colonize their own wounds, whereas in the exogenous route burn wounds are cross-infected from other sources. In this study we evaluated the effect of blocking the endogenous route on S. aureus burn wound colonization by mupirocin application in the nose of patients at the time of admission.

METHODS

From September 2000 to January 2002 all patients with burns admitted to a single dedicated Burn Centre received nasal mupirocin upon admission. This period was compared to two control periods (C1: July 1999 to July 2000 and C2: January 2002 to January 2003) for S. aureus burn wound colonization. The colonization risk was analysed, adjusting for confounding, with Cox proportional hazard regression.

RESULTS

A total of 98 patients did not have S. aureus burn wound colonization at the time of admission and were, thus, considered at risk for S. aureus acquisition during their stay. As compared to C1, the relative risk of acquiring S. aureus in their wound was 0.48 (95% CI: 0.24-0.97) in the mupirocin period and 0.55 (95% CI: 0.28-1.1) during the C2 period. S. aureus nasal/pharyngeal colonization was a significant independent risk factor for wound colonization (RR: 2.3; 95% CI: 1.2-4.2).

CONCLUSION

Nasal mupirocin may contribute to risk reduction of S. aureus wound colonization in patients with burns.

Enteral vancomycin controls methicillin-resistant Staphylococcus aureus endemicity in an intensive care burn unit: a 9-year prospective study

OBJECTIVE

The aim of this study was to assess the efficacy and safety of enteral vancomycin in controlling MRSA endemicity in an intensive care burn unit.

SUMMARY BACKGROUND DATA

MRSA is a serious clinical and epidemiologic problem. It is not uncommon that the traditional maneuvers, detection and isolation of carriers, fail to control endemicity due to MRSA.

METHODS

All patients admitted to an Intensive Care Burn unit from January 1995 to February 2004 have been included in this prospective cohort study comprised 2 different periods. During period 1 (January 1995 to January 2000), barrier and isolation measures were enforced. During period 2 (February 2000 to February 2004), patients received enteral vancomycin 4 times daily in addition to selective digestive decontamination.

RESULTS

A total of 777 patients were enrolled into the study: 402 in period 1, and 375 in period 2. There were no significant differences in the characteristics of patients between the 2 periods, except for the total body surface burned area, 30.3% in period 1 and 25.61% in period 2 (P = 0.009). There was a significant reduction in the incidence of patients who acquired MRSA from 115 in period 1 to 25 in period 2 (RR, 0.22; 95% confidence interval [CI], 0.15-0.34). Similar reductions were observed in the number of patients with wound (RR, 0.20; 95% CI, 0.12-0.32), blood (RR, 0.13; 95% CI, 0.04-0.35), and tracheal aspirate (RR, 0.07; 95% CI, 0.03-0.19), samples positive for MRSA. There was no emergence of either vancomycin-resistant enterococci or Staphylococcus aureus with intermediate sensitivity to glycopeptides in period 2.

CONCLUSIONS

Enteral vancomycin is an effective and safe method to control MRSA in intensive care burn units without VRE.

Outbreak of epidemic methicillin-resistant Staphylococcus aureus in a regional burns unit: Management and implications

Colonization of burn patients with methicillin-resistant Staphylococcus aureus (MRSA) is not uncommon, however an outbreak that necessitates closure of a burns unit is relatively rare. The objective of this study was to present the experience of a regional adult burns unit where an outbreak of epidemic MRSA-15 (EMRSA-15) took place. During the studied period, 176 patients were admitted to the unit, 52 with burns, 48 for elective plastic surgery procedures while the remainder belonged to other specialties. Patients admitted under burns and plastic surgery were investigated together with 46 staff members to control the outbreak. MRSA was isolated in 18 patients out of which 12 had EMRSA-15. Among the staff members, MRSA was isolated in nine of which five had EMRSA-15. The burns unit was closed to all admissions to terminate this outbreak. The MRSA positive staff members were sent on "special leave" and underwent treatment with nasal mupirocin and triclosan body wash. All staff members were able to return to work after one week's treatment. The burns unit underwent re-furbishment and decontamination while it was closed. In conclusion, the study shows that an outbreak of EMRSA was controlled successfully, however, it highlights the implications of such an event for a regional burn service with regard to staff, patients and guidelines for management.

Molecular epidemiology of Staphylococcus aureus colonization in a burn center

The aim of this study was to investigate carriage of Staphylococcus aureus by patients and health care workers (HCW) and to define the genetic relationship of S. aureus strains isolated from burn wounds. At admission, 19/55 (34.5%) patients carried S. aureus in their nose and/or throat. Of this group, 95% subsequently colonized their burn wounds with S. aureus. Molecular analysis showed that in 78% of these cases the burn-wound colonizing strain was identical to the strain carried at admission. Importantly, 23/36 (64%) patients who did not carry S. aureus at admission also developed burn-wound colonization. In this group, three dominant genotypes were identified as colonizing strains of burn wounds. These clones represented also the majority (59%) of S. aureus strains cultured from the nose and/or throat of health care workers and patients. If patients were admitted to one of the Intensive Care rooms burn wounds of non-carriers were not colonized with S. aureus as long as they remained in such isolation. Only patients who carried S. aureus at admission developed burn-wound colonization with that genotype they carried in the nose or throat. Both carriage in patients and health care workers and auto-infection play a crucial role in (cross-) colonization events.

Outcome analysis of intraabdominal infection with resistant gram-positive organisms

BACKGROUND

Although the microbiology of intraabdominal infection has been well described, the role of resistant organisms remains unclear. To evaluate the hypothesis that intraabdominal infections from resistant gram-positive cocci (rGPC) have worse outcomes compared to those with susceptible organisms, patient characteristics and outcomes were compared between these groups.

METHODS

Analysis of peritoneal infections was performed on prospectively collected data of all consecutive surgical infections from December 1996 to June 1999 at a university hospital. Intraabdominal infection was defined either by a positive peritoneal cavity culture or on clinical grounds (e.g., abscess), which prompted antimicrobial or surgical therapy. Resistant Staphylococcus and Enterococcus spp. were defined as those strains resistant to oxacillin, gentamicin, or vancomycin.

RESULTS

Compared to episodes of intraabdominal infection from susceptible organisms (n = 365), infections due to rGPC (n = 52) were associated with an increased severity of illness (p < 0.0001), longer time from admission to treatment (p < 0.0001), longer duration of therapy (p = 0.008), greater proportion of nosocomial infection (p < 0.0001), increased length of stay (p < 0.0001), and an increased mortality rate (9% versus 23%; p = 0.003). However, comparison of intraabdominal infection with rGPC to a group controlled for severity of illness demonstrated a prolonged time from admission until treatment and longer duration of hospitalization but a similar mortality rate between groups (17% versus 23%; p = 0.46).

CONCLUSION

Intraabdominal infection with rGPC is an indicator of poor prognosis and severe illness. Although not an independent predictor of mortality, the significantly increased duration of therapy and prolonged duration of hospitalization may have considerable economic impact.

MRSA-retrospective analysis of an outbreak in the burn centre Aachen

The growing interest in methicillin-resistant Staphylococcus aureus (MRSA) has been caused by its increased appearance in hospital and community populations. In our burn centre, an outbreak of MRSA was noticed during an 8-month period. We were able to isolate MRSA in eight patients. DNA analysis by pulsed-field gel electrophoresis (PFGE) demonstrated the development of five different strains during this period. Only two patients developed an infection caused by MRSA colonisation. The infections were proven by positive blood culture or catheter colonisation. One patient developed a clinical vancomycin-resistant sepsis which was treated successfully with the additional application of Quinupristin/Dalfopristin. THIS ANALYSIS SHOWS THAT: (1) the development of MRSA in a burn unit is often created in a single patient by long-term antibiotic therapy and not a result of cross-infection, (2) manifest MRSA infection seldom occurs even in colonised burn patients, and (3) a clinically vancomycin-resistant MRSA infection in burn patients can be treated sufficiently with Quinupristin/Dalfopristin.

Colonization with methicillin-resistant Staphylococcus aureus in ICU patients: morbidity, mortality, and glycopeptide use

OBJECTIVE

To determine the impact of methicillin-resistant Staphylococcus aureus (MRSA) colonization on the occurrence of S. aureus infections (methicillin-resistant and methicillin-susceptible), the use of glycopeptides, and outcome among intensive care unit (CU) patients.

DESIGN

Prospective observational cohort survey.

SETTING

A medical-surgical ICU with 10 single-bed rooms in a 460-bed, tertiary-care, university-affiliated hospital.

PATIENTS

A total of 1,044 ICU patients were followed for the detection of MRSA colonization from July 1, 1995, to July, 1 1998.

METHODS

MRSA colonization was detected using nasal samples in all patients plus wound samples in surgical patients within 48 hours of admission or within the first 48 hours of ICU stay and weekly thereafter. MRSA infections were defined using Centers for Disease Control and Prevention standard definitions, except for ventilator-associated pneumonia and catheter-related infections, which were defined by quantitative distal culture samples.

RESULTS

One thousand forty-four patients (70% medical patients) were included in the analysis. Mean age was 61+/-18 years; mean Simplified Acute Physiologic Score (SAPS) II was 36.4+/-20; and median ICU stay was 4 (range, 1-193) days. Two hundred thirty-one patients (22%) died in the ICU. Fifty-four patients (5.1%) were colonized with MRSA on admission, and 52 (4.9%) of 1,044 acquired MRSA colonization in the ICU. Thirty-five patients developed a total of 42 S. aureus infections (32 MRSA, 10 methicillin-susceptible). After factors associated with the development of an S. aureus infection were adjusted for in a multivariate Cox model (SAPS II >36: hazard ratio [HR], 1.64; P=.09; male gender: HR, 2.2; P=.05), MRSA colonization increased the risk of S. aureus infection (HR, 3.84; P=.0003). MRSA colonization did not influence ICU mortality (HR, 1.01; P=.94). Glycopeptides were used in 11.4% of the patients (119/1,044) for a median duration of 5 days. For patients with no colonization, MRSA colonization on admission, and ICU-acquired MRSA colonization, respectively, glycopeptide use per 1,000 hospital days was 37.7, 235.2, and 118.3 days. MRSA colonization per se increased by 3.3-fold the use of glycopeptides in MRSA-colonized patients, even when an MRSA infection was not demonstrated, compared to non-colonized patients.

CONCLUSIONS

In our unit, MRSA colonization greatly increased the risk of S. aureus infection and of glycopeptide use in colonized and non-colonized patients, without influencing ICU mortality. MRSA colonization influenced glycopeptide use even if an MRSA infection was not demonstrated; thus, an MRSA control program is warranted to decrease vancomycin use and to limit glycopeptide resistance in gram-positive cocci.

Bacterial endocarditis following a minor burn injury. Case report and review

A case of bacterial endocarditis in a patient with a total burn area of less than 1% is presented. A high index of suspicion for bacterial endocarditis should exist for any burns patient, regardless of burn size, who becomes unwell and has positive blood cultures.

From the Journals

PRESSURE ULCER RISK ASSESSMENT IN INTENSIVE CARE SETTINGS MRSA IN BURN PATIENTS LONG-STRETCH AND SHORT- STRETCH BANDAGING HEALING RATES AND TREATMENT COSTS IN COMPRESSION BANDAGING.