Prevalence of multidrug-resistant organisms recovered at a military burn center

Infections caused by multidrug-resistant (MDR) pathogens are associated with significant morbidity and mortality in patients with burn injuries. We performed a 6-year antibiotic susceptibility records review from January 2003 to December 2008 to assess the prevalence of MDR isolates by pathogen at the US Army Institute of Surgical Research Burn Center. During the study period Acinetobacter baumannii (780 isolates [22%]) was the most prevalent organism recovered, followed by Pseudomonas aeruginosa (703 isolates [20%]), Klebsiella pneumoniae (695 isolates [20%]), and Staphylococcus aureus (469 isolates [13%]). MDR prevalence rates among these isolates were A. baumannii 53%, methicillin-resistant S. aureus (MRSA) 34%, K. pneumoniae 17% and P. aeruginosa 15%. Two isolates, 1 A. baumannii and 1 P. aeruginosa, were identified as resistant to all 4 classes of antibiotics tested plus colistin. A. baumannii isolates recovered from patients with burns greater than 30% of total body surface area (TBSA) were more likely to be MDR (61%) with no significant difference for P. aeruginosa and K. pneumoniae. A higher proportion of MDR P. aeruginosa isolates were recovered from respiratory specimens compared to blood specimens (24% vs. 9%) while the opposite was true for MRSA (35% vs. 54%). A comparison of A. baumannii recovered during hospitalization days 1–5 and 15–30 revealed higher MDR levels as length of stay increased (48% vs. 75%) while no significant trends were observed for P. aeruginosa and K. pneumoniae. A similar pattern was observed for MDR A. baumannii levels for the facility between 2003 and 2005 and 2006–2008 (39% vs. 70%), with no significant increase in MDR P. aeruginosa and MDR K. pneumoniae. Increasing antibiotic resistance patterns of the most prevalent isolates recovered during extended hospitalization, impact of % TBSA and other clinical parameters may affect empirical antimicrobial therapy and patient management decisions during treatment.     

Comparison of pathogens and antibiotic resistance of burn patients in the burn ICU or in the common burn ward

Background

This study aims to compare pathogens and their antibiotic resistances of burn patients from burn intensive care unit (ICU) or common burn ward. Of 2395 clinical samples from 63 patients in burn ICU, pathogens were detected in 1621 samples, in which 1203 strains (74.2%) were Gram negative bacteria, 248 strains (15.3%) were Gram positive bacteria, 170 strains (10.5%) were fungi. Top-4 microorganisms isolated from patients in burn ICU were Bauman's Acinetobacter (557, 34.4%), Pseudomonas aeruginosa (287.17.7%), Staphylococcus aureus (199, 12.3%) and Klebsiella pneumoniae (171, 10.5%). Of 512 clinical samples from 235 patients in common burn units, pathogens were detected in 373 samples, in which 189 (50.6%) strains were Gram negative bacteria, 150 strains (40.2%) were Gram positive bacteria, 34 strains (9.2%) were fungi. Top-4 microorganisms isolated from patients in common burn units were S. aureus (103, 27.6%), P. aeruginosa (46, 12.3%), K. pneumoniae (38, 10.2%) and Escherichia coli (32, 8.6%). Antibiotic resistance rates of pathogens isolated from clinical samples of burn patients from ICU was significantly higher than those from common units.

Conclusions

Pathogens and their antibiotic resistances are significantly different between burn ICU and common burn units. This finding has great implication for infection control in burn patients.     

Description of Streptococcus pneumoniae infections in burn patients

Background

Longer survival in burn patients has resulted in more infectious complications, typically with Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus. Although Streptococcus pneumoniae infections are common in the community and can cause nosocomial infections, the incidence and risk factors for pneumococcal infections in burn patients is unclear.

Methods

We performed an electronic retrospective chart review to collect rates of and risk factors for S. pneumoniae infections in patients with thermal burns from March 2003 through June 2008.

Results

Of the 1838 patients admitted to the burn center, 10 were infected (0.54% incidence). Patients presented with pneumonia (seven patients, 0.38% incidence) and bacteremia (three patients, 0.16% incidence) within a week of initial burn (median 1 day, range 0–8), often in the setting of bacterial co-infection (five patients). This group was mainly young males with median 28.8% total body surface area burns; 60% had concomitant inhalational injury. Most did not have traditional risk factors for pneumococcal infection but had objective signs of infection at time of positive culture and were treated with appropriate antibiotics. Two patients in this series died, although no mortality was attributed to S. pneumoniae.

Conclusions

Pneumococcal disease is not common in burn patients and generally occurs early on in hospitalization after burn making it more likely to be a community-acquired pathogen rather than nosocomial in the burn population. It should be considered in the setting of sepsis or new pulmonary infiltrates within a week after burn, but typical empiric antibiotics against the usual burn pathogens should be adequate to also treat for pneumococcal infection.     

Common pathogens in burn wound and changes in their drug sensitivity

Infection is an important cause of mortality in patients with burns. Rapid emergence of hospital pathogens and antibiotic-resistant organisms necessitate periodic evaluation of bacterial colonisation patterns and antibiogram sensitivity in burn wards.In this study, which was conducted in a 3 months’ period in 2009, 106 samples from the wounds of 59 patients admitted in a burn ward were taken, one in the 1st and one between the 3rd and the 7th days.Pseudomonas aeruginosa, Acinetobacter and Klebsiella were the most common Gram-negative and Staphylococcus aureus was the most common Gram-positive organisms recovered from the patients.This study showed a high rate of resistance to the administered antibiotics. The prevalent Gram-negative organisms in our ward were resistant to ceftazidime and imipenem in nearly 90% and 20% of cases, respectively.     

Recurrent bacteremia: A 10-year retrospective study in combat-related burn casualties

IntroductionSurviving the first episode of bacteremia predisposes burn casualties to its recurrence. Herein, we investigate the incidence, mortality, bacteriology, and source of infection of recurrent bacteremia in military burn casualties admitted to the U.S. Army Institute of Surgical Research Burn Center over a 10 year period.MethodsBacteremia was defined as the growth of Gram-positive or Gram-negative organisms in a blood culture that excluded probable skin contaminants. Recurrent bacteremia was defined as a subsequent episode of bacteremia ≥7 days after the first episode. Polymicrobial bacteremia was the presence of more than one pathogen in the same blood culture. Bacteremia was attributed to UTI, pneumonia, or wound sepsis. All other bacteremias were considered non-attributable bloodstream infections. Univariate and multivariate analyses determined factors predictive of clinical outcome.ResultsOut of 952 combat-related burn casualties screened, 166 cases were identified; 63% (non-recurrent) and 37% (recurrent) with median time to recurrence of 20 days. Univariate and multivariate analysis showed that the mortality rate was two and nine-fold, respectively, higher with recurrent bacteremia. Univariate analysis found that except for urinary tract infection, large burn size (>20%), 3rd degree burns, increased injuiry severity, perineal burns, and mechanical ventilator days were independent factors predictive of recurrence of bacteremia as well as increased mortality in the recurrent bacteremia cohort. Acinetobacter baumannii complex (63%) was prevalent in the non-recurrent group, while Klebsiella pneumoniae (46% vs. 30%) and Pseudomonas aeruginosa (35% vs. 26%) were prevalent in recurrent bacteremia. Half of the recurrent bacteremia cases were polymicrobial, compared to 9% in non-recurrent bacteremia. Pneumonia was prevalent in non-recurrent bacteremia (38%) and a combination of pneumonia and wound sepsis (29%) in recurrent bacteremia casualties.ConclusionsRecurrent bacteremia increases mortality in military burn casualties. Additional research is needed to address and mitigate the underlying causes, thereby improving survival.     

Evaluations of bacterial contaminated full thickness burn wound healing in Sprague Dawley rats Treated with Tualang honey

Aim:

The effect of Tualang honey on wound healing in bacterial contaminated full-thickness burn wounds was evaluated in 36 male Sprague Dawley rats.

Materials and Methods:

The rats were randomly divided into three groups (n = 12/group). Three full-thickness burn wounds were created on each rat. Each group of rats was inoculated with a different organism in the burn wounds: Group A was inoculated with Pseudomonas aeruginosa, Group B was inoculated with Klebsiella pneumoniae and Group C was inoculated with Acinetobacter baumannii. One wound on each rat was dressed with either Tualang honey, Chitosan gel or Hydrofibre silver. Each wound size was measured on day 3, 6, 9, 12, 15, 18 and 21 of the study.

Results:

The mean wound size of the Tualang honey-treated wounds was not statistically different than that of the Chitosan gel or Hydrofibre silver-treated wounds when the wounds were compared throughout the entire experiment (P > 0.05). However, comparing the mean wound size on day 21 alone revealed that the Tualang honey-treated wounds were smaller in comparison to that of the Chitosan gel and Hydrofibre silver-treated groups.

Conclusions:

This study shows that topical application of Tualang honey on burn wounds contaminated with P. aeruginosa and A. baumannii gave the fastest rate of healing compared with other treatments.     

Stenotrophomonas maltophilia bacteremia in burn patients

Stenotrophomonas maltophilia has been increasingly reported as a nosocomial opportunistic pathogen in debilitated patients, including burn patients. There is, however, only one published report in English that discusses S. maltophilia bacteremia in burns. We performed a retrospective chart review and statistical analysis of the incidence, the duration of hospital stays before a diagnosis of bacteremia, antimicrobial susceptibility, prognosis, and mortality risk factors in burn patients. From January 1996 to December 2004, 14 episodes of S. maltophilia bacteremia in 13 of 666 patients admitted to the burn center at our hospital were identified. The patients, nine males and four females, ranged in age from 1 to 76 years (mean: 42.9+/-24.4 years). Eleven injuries were from flame burns and two were from scald burns. The mean total burned surface area (TBSA) was 47+/-30.2% and mean prognostic burn index (PBI) was 81.7+/-31.3. The average annual incidence was 2.3 episodes per 1000 admissions, and no outbreak cluster was noticed. The mean hospital stay before bacteremia was 19.8+/-11.9 days. Most isolates were susceptible to ticarcillin-clavulanate (87.5%) and moxalactam (85.7%). The overall mortality was 30.7% (4/13) and correlated significantly with TBSA (P<0.01) and PBI (P<0.05). The incidence of S. maltophilia bacteremia was higher in hospitalized burn patients than in hospitalized non-burn patients. Different antimicrobial susceptibility patterns may exist, especially in different geographic regions. Awareness of the possibility of infection by this opportunistic pathogen and commencement of adequate antibiotics treatment, especially after 3 weeks of intensive care, should be incorporated into the strategy of treatment in major burn patients.     

Activity of topical antimicrobial agents against multidrug-resistant bacteria recovered from burn patients

Background

Topical antimicrobials are employed for prophylaxis and treatment of burn wound infections despite no established susceptibility breakpoints, which are becoming vital in an era of multidrug-resistant (MDR) bacteria. We compared two methods of determining topical antimicrobial susceptibilities.

Methods

Isolates of Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), extended spectrum beta-lactamase (ESBL) producing Klebsiella pneumoniae, and Acinetobacter baumanii-calcoaceticus (ABC) from burn patients were tested using broth microdilution and agar well diffusion to determine minimum inhibitory concentrations (MICs) and zones of inhibition (ZI). Isolates had systemic antibiotic resistance and clonality determined. MDR included resistance to antibiotics in three or more classes.

Results

We assessed 22 ESBL-producing K. pneumoniae, 20 ABC (75% MDR), 20 P. aeruginosa (45% MDR), and 20 MRSA isolates. The most active agents were mupirocin for MRSA and mafenide acetate for the gram-negatives with moderate MICs/ZI found with silver sulfadiazene, silver nitrate, and honey. MDR and non-MDR isolates had similar topical resistance. There was no clonality associated with resistance patterns.

Conclusion

Despite several methods to test bacteria for topical susceptibility, no defined breakpoints exist and standards need to be established. We recommend continuing to use silver products for prophylaxis against gram-negatives and mafenide acetate for treatment, and mupirocin for MRSA.     

Reducing the spread of Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus on a burns unit through the intervention of an infection control bundle

Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii are major nosocomial pathogens in burns units. We investigated the impact of an infection control bundle on the incidence of nosocomial MRSA and A. baumannii in our burns unit, comparing a pre-intervention period (December 2006–August 2008) with an intervention period (September 2008–December 2009). The bundle comprised regular hydrogen peroxide vapour (HPV) disinfection of the rooms following discharge of patients colonized or infected by multidrug-resistant bacteria, pre-emptive cohort isolation of newly admitted patients before being proven culture negative, cohorting of colonized or infected patients, installation of two air disinfection systems in the corridors of the unit and improvement of material storage. We also investigated the microbiological efficacy of HPV disinfection by sampling the environment before and after HPV treatments. HPV disinfection eliminated pathogens from the environment and significantly reduced total bacterial surface counts, and total fungal air and surface counts, on both a unit and room scale. The incidence of nosocomial MRSA infection or colonization fell by 89.3% from 7.22 to 0.77 cases/1000 patient days (p < 0.0001) and A. baumannii fell by 88.8% from 6.92 to 0.77 cases/1000 patient days (p = 0.002) in the intervention period with no further outbreaks of these organisms occurring in this period. The infection control bundle resulted in a significant reduction in the incidence of nosocomial MRSA and A. baumannii in our burns unit and prevented further outbreaks of these organisms.     

An in vitro biofilm model to examine the effect of antibiotic ointments on biofilms produced by burn wound bacterial isolates

Purpose

Topical treatment of burn wounds is essential as reduced blood supply in the burned tissues restricts the effect of systemic antibiotics. On the burn surface, microorganisms exist within a complex structure termed a biofilm, which enhances bacterial resistance to antimicrobial agents significantly. Since bacteria differ in their ability to develop biofilms, the susceptibility of these biofilms to topically applied antibiotics varies, making it essential to identify which topical antibiotics efficiently disrupt or prevent biofilms produced by these pathogens. Yet, a simple in vitro assay to compare the susceptibility of biofilms produced by burn wound isolates to different topical antibiotics has not been reported.

Methods

Biofilms were developed by inoculating cellulose disks on agar plates with burn wound isolates and incubating for 24 h. The biofilms were then covered for 24 h with untreated gauze or gauze coated with antibiotic ointment and remaining microorganisms were quantified and visualized microscopically.

Results

Mupirocin and triple antibiotic ointments significantly reduced biofilms produced by the Staphylococcus aureus and Pseudomonas aeruginosa burn wound isolates tested, as did gentamicin ointment, with the exception of one P. aeruginosa clinical isolate.

Conclusions

The described assay is a practical and reproducible approach to identify topical antibiotics most effective in eliminating biofilms produced by burn wound isolates.     

Universal contact precautions do not change the prevalence of antibiotic resistant organisms in a tertiary burn unit

Objective

The prevalence of antibiotic-resistant organisms (ARO) in burn units is increasing worldwide and contributes significantly to morbidity and mortality. Study aims are to describe the burden of AROs in burn patients admitted to a tertiary burn unit, to evaluate the impact of contact precautions implemented after an outbreak of antibiotic-resistant Acinetobacter baumannii, and to identify possible predictors of ARO acquisition.

Genotyping of Pseudomonas aeruginosa strains isolated from burn patients by RAPD-PCR

Background

Pseudomonas aeruginosa is one of the important causes of nosocomial infections that easily gains resistance to many antibiotics. This opportunistic pathogen is a major health hazard particularly in immunodeficient patients, patients in intensive care units (ICU) and burn units with life threatening outcome. The bacterium may be originated from different or common sources, and comprises a high colonization and transmission capacity.

Objective

The aim of present study was to investigate the genotypic variation of Pseudomonas aeroginosa strains isolated from burn patients by using Random Amplified Polymorphic DNA (RAPD) method.

Methods

Totally 70 clinical samples were collected from burn patients in Taleghani Burn Hospital of Ahvaz. Fifty out of total samples were positive for P. aeruginosa by application of conventional culture and biochemical identification tests. DNA was extracted from the isolates and the RAPD-PCR method was applied to the DNA extracts according to standard method using a short single primer of 272. The technique created repetitive electrophoresis patterns which was used for genotypic differentiation.

Results

RAPD-PCR, created 9 genotypic profiles designated as I–IX with base pair length ranging from 180 to 2700. Each genotype showed between 3 and 6 different weight DNA bands. Genotype I was the most prevalent, identified in 10 bacterial isolates (20%). Genotypes I, II and VI were mostly common in patients with more severe burn, and were mainly isolated from wound and blood samples obtained from the same patients.

Conclusion

In present study, we found RAPD-PCR technique as a useful tool for investigation of the genetic variation among P. aeruginosa strains. This is a rapid, low cost, genotypic method with high discriminatory power. The results could assist to screen for the original of infection caused by this organism with subsequent control of colonization and transmission.     

Contribution of bacterial and viral infections to attributable mortality in patients with severe burns: An autopsy series

Bacterial infections are a common cause of mortality in burn patients and viral infections, notably herpes simplex virus (HSV) and cytomegalovirus (CMV) have also been associated with mortality. This study is a retrospective review of all autopsy reports from patients with severe thermal burns treated at the US Army Institute of Research (USAISR) burn unit over 12 years. The review focused on those patients with death attributed to a bacterial or viral cause by autopsy report. Of 3751 admissions, 228 patients died with 97 undergoing autopsy. Death was attributed to bacteria for 27 patients and to virus for 5 patients. Bacterial pathogens associated with mortality included Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. This association with mortality was independent of % total body surface area burn, % full-thickness burn, inhalation injury, and day of death post-burn. Bloodstream infection was the most common cause of bacteria related death (50%), followed by pneumonia (44%) and wound infection (6%). Time to death following burn was ≤7 days in 30%, ≤14 days in 59% and ≤21 days in 67%. All of the viral infections associated with mortality involved the lower respiratory tract, HSV for 4 and CMV for 1. Four of these 5 patients had evidence of inhalation injury by bronchoscopy, all had facial and neck burns, and 2 had concomitant Staphylococcus pneumonia. Time to death following burn ranged from 14 to 42 days for the 5 patients. Despite advances in care, gram negative bacterial infections and infection with S. aureus remain the most common cause of bacteria related mortality early in the hospital course. Viral infections are also associated with mortality and numbers have remained stable when compared to data from prior years.     

Comparative evaluation of povidone-iodine aerosol foam solution and silver sulphadiazine cream as prophylactic topical antibacterial agents for treatment of the burn wound

Nine patients with fresh burns were treated with povidone-iodine aerosol foam solution and matched with 9 patients with fresh burns of similar extent and distribution treated with silver sulphadiazine cream. Severe pain at the time of application of povidoneiodine was a constant complaint. The wounds of 7 patients treated with povidone-iodine had been colonized by bacteria by day 11 post burn, whereas the wounds of only 2 patients treated with silver sulpha-diazine had been colonized at the corresponding time. Gram-negative organisms appeared more frequently, earlier and in higher concentrations in the povidoneiodine treated patients (Pseudomonas aeruginosa, 4 patients), whereas Staphylococcus aureus was more frequent with silver sulphadiazine (4 patients). Five of the povidone-iodine treated patients had developed burn wound sepsis by day 11 post burn, whereas no silver sulphadiazine treated patient developed burn wound sepsis. For this reason, further evaluation of povidone-iodine foam as a prophylactic topical antibacterial for burns was abandoned.     

Common hydrotherapy practices and the prevalence of burn wound bacterial colonisation at the University Teaching Hospital in Lusaka,Zambia

BackgroundIn many parts of the world, hydrotherapy plays an important role in the management of patients with wounds including burns. Different centers practice hydrotherapy differently. At the University Teaching Hospital in Lusaka, Zambia, burn patients use a common bathtub for cleaning their wounds which theoretically increases the risk of cross-infection, an important source of morbidity and mortality. There is currently no evidence that hydrotherapy as practiced at our institution leads to cross infection among patients with burns.ObjectiveThe objective was to determine if our hydrotherapy practice and water plays a role in cross-infection and what organisms cause this infection.MethodsThis was a prospective analytical study. Patients meeting the selection criteria were recruited. Swabs from the burn wounds were collected on admission (day 0), day 4 and day 7. Weekly swabs of the bathtub were also collected, after the tub had been cleaned and declared ready for the next patient. Weekly water samples were also collected. Selected results, for Staphylococcus aureus and Klebsiella pneumoniae, were subjected to further analysis and PCR. Results were analyzed using statistics software, SPSS version 23.ResultsIn this study, there were 96 participants of which 51 (53.1%) were males and 45 (46.9%) were females. Age distribution ranged from 5months to 91 years. The modal age range was 1 to 2 years. The modal burn percentage was 6%–10%, followed by 11%–15%. Hot water was the cause of burns in 65.6%. S. aureus and K. pneumoniae were the most common organisms isolated. Others were enteric organisms. In terms of readily available antibiotics, there was more sensitivity to Amikacin and Chloramphenicol than Ciprofloxacin (our commonly used antibiotic). The bathtub also had S. aureus and K. pneumoniae, besides enteric organisms. Sixty five point four percent (65.4%) of the Klebsiella were ESBL (Extended Spectrum Beta Lactamase) producers. The tub had samples that were both ESBL producers as well as widely resistant Klebsiella by other means. No growth was obtained from the water samples. Seventy-two point nine percent (72.9%) of the patients were discharged, 19.8% died, while 7.3% left against medical advice.ConclusionHydrotherapy as currently practiced at the University Teaching Hospital does contribute significantly to cross-infection among burn patients with widely resistant organisms. The main ones are S. aureus and K. pneumoniae. Switching care to a shower mechanism might help eliminate this problem as the study demonstrates that no bacteria were found in the water samples.     

Burn-associated bloodstream infections in pediatric burn patients: Time distribution of etiologic agents

Background

Infections are the leading cause of morbidity and mortality in patients with burns in burn units. Bloodstream infections (BSIs) in patients with burns may result from burn wound infection, use of invasive devices such as central venous catheters, and translocation of the gastrointestinal flora.

Blood stream infections (BSI) in severe burn patients—Early and late BSI: A 9-year study

Bloodstream infections (BSI) and sepsis are among the most common complications occurring in severe burn patients. This study was designed to evaluate changes in BSI pathogens over almost a decade in severe burn patients at Rambam Healthcare Campus, and BSI occurrence during early and late hospitalization periods. Retrospective computerized data was retrieved from all severe burn patients hospitalized in our institution during the years 2001–2009. BSI in the first week was defined as early BSI, and in the second week and beyond, late BSI. Of 159 severe burns patients, 74 had at least one BSI episode. Most first BSI episodes were diagnosed during the first week of hospitalization. In late BSI, an increased prevalence of resistant bacteria (methicillin-resistant Staphylococcus aureus [MRSA], carbapenem-resistant Klebsiella pneumoniae [CRKP], imipenem-resistant Pseudomonas aeruginosa [PSE-IMP]) and Candida spp. were observed. However, over the 9-year study period, only CRKP increased significantly. In summary, except for the sudden appearance and increase in CRKP (8% increase; p = 0.045), we did not observe a significant change in the BSI pathogen profile over the 9-year period. Nevertheless, over the hospitalization period, there is a clear change in the BSI bacteria profile, especially after 4 weeks of hospitalization.     

Antimicrobial susceptibility and ESBL prevalence in Pseudomonas aeruginosa isolated from burn patients in the North West of Pakistan

Pseudomonas aeruginosa is one of the most prevalent pathogen in burn infections. Infections with P. aeruginosa are associated with higher mortality rate and antibiotic costs in hospitalized patients. These bacteria also produce enzymes called Expanded Spectrum Beta-Lactamases (ESBL) which render penicillins and cephalosporins inactive. The aim of this study was to assess the antimicrobial susceptibility pattern and prevalence of ESBL in P. aeruginosa in Peshawar, North West of Pakistan. During 2005–2006, one hundred and six P. aeruginosa isolates were collected from burn patients at a tertiary care hospital. Antibiotic susceptibility testing and ESBL detection were carried out according to Clinical Laboratory and Standards Institute (CLSI) criteria. Eighteen antibiotics were tested in this study. A total of 38 (35.85%) isolates were found to be ESBL producers. Thirty one (29.24%) isolates were resistant to 3 or more antibiotics (multidrug resistance). Meropenem and imipenem showed high potency with 99% and 96% isolates being susceptible respectively. Susceptibility to amikacin was 70%; gentamicin 25%; ciprofloxacin 49%; enoxacin 47%; gatifloxacin 42%; doxycycline 21% and to co-trimoxazole only 16%. This study reveals that P. aeruginosa isolated from burns in this region are multidrug resistant and produce ESBL in large proportions.     

An outbreak of a multiresistant methicillin-susceptible Staphylococcus aureus (MR-MSSA) strain in a burn centre: the importance of routine molecular typing

Here we report an outbreak among 17 patients caused by a single strain of a Multiresistant Methicillin-Susceptible Staphylococcus aureus (MR-MSSA) in a burn centre. The MR-MSSA strains were resistant to penicillin, ciprofloxacin, erythromycin, clindamycin and co-trimoxazole. Further analysis showed an increased prevalence of MR-MSSA carriership in S. aureus colonized patients admitted to the burn centre, from 0% in 2005 (0/118), 3.3% in 2006 (4/121), 6.1% in 2007 (6/99), to 7.8% in 2008 (7/90). Molecular typing with Amplified Fragment Length Polymorphism showed that all MR-MSSA isolates derived from burn centre patients had a unique genotype, and was different compared to isolates derived from other hospital patients. All healthcare workers (HCWs) who worked in the burn centre during the outbreak were screened for nasal carriage with MR-MSSA. One HCW tested positive for a genotype of MR-MSSA that was indistinguishable from the genotype found in samples of the burned patients. No new cases of MR-MSSA colonization or infection were identified after the colonized HCW stopped working at the burn centre. The routine practice of molecular typing of collected S. aureus strains from both patients and HCWs will help to detect nosocomial spread in a burn centre, and opens the possibility of a rapid, almost pre-emptive response.