Staphylococcal enzyme; Methicillin-resistant Staphylococcus aureus; burn
Objective To evaluate the effect of compound lysostaphin on MRSA infection in burn wounds. Methods The treatment of MRSA infection in 67 burn patients was analyzed retrospectively. Results 67 patients were cured by compound lysostaphin treatment. Conclusion compound lysostaphin is very effective in controlling MRSA infection in burn wounds.
Keywords lysostaphin; MRSA burn
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important pathogens of nosocomial infection. MRSA accounts for the majority of all kinds of wound infections in the late stage of burn [1]. Because methicillin-resistant Staphylococcus aureus has multiple drug resistance, the increase of strains has become a difficult problem in hospital infection control. In burn treatment, once MRSA infection appears in the residual wound, it is difficult to treat. From June 2006 to June 2009, 67 patients with MRSA infection in burn department of our hospital were treated with compound lysostaphin [2], and satisfactory results were obtained. The report is as follows.
Clinical data of 1
There were 67 patients in this group, including 49 males and 8 females/kloc-0, aged 2-42 years. The total burn area 16% ~ 75% was MRSA infection in residual wounds. Among them, 59 cases were infected by MRSA alone, and 8 cases were infected by other bacteria. The infection time was 14 ~ 26 d after injury.
2 Treatment and results
For patients with MRSA infection in small wounds, small pustullike invasive infection lesions with a diameter less than 5 mm are removed from the healed wounds or even normal skin, and then povidone iodine complex is applied to the wounds twice a day. For scattered wounds less than 2 cm in diameter, the wounds were washed with 3% hydrogen peroxide solution, isotonic saline solution and bromogeramine solution in turn, and then sprayed with compound staphylococcal enzyme spray (Shanghai Hi-Tech Bioengineering Co., Ltd., approval number: Weixiaozi 2002 0062) twice a day. 1 ~ 2 weeks later, the infection was controlled and the wound healed. Patients with MRSA infection with large residual wounds were given systemic support treatment, and the wounds were wet-packed with compound staphylococcal enzymes. After the infection was basically controlled, skin grafting was performed to seal the wound. According to the results of drug sensitivity test, vancomycin, norvancomycin, ofloxacin and other antibiotics were systematically used. 67 patients were treated with compound lysostaphin, and the infection was effectively controlled and the wound healed.
Typical case: The patient is a 36-year-old male. The flame burned many parts of the body, with a total area of 75%. After 26 days of treatment in other hospitals, 46% of the residual wounds after burns were admitted to our hospital. When people were admitted to hospital, they took wound secretions for culture, and the result was MRSA infection. After admission, the wound was wet-packed with compound staphylococcal enzyme, and 0.4 g, 2 norvancomycin was given intravenously twice a day. Autologous thick skin transplantation was performed 8 days and18 days after admission, and the survival rate of skin graft was about 80%. After 15 d operation, patches of yellow secretion appeared under the living skin. Samples were taken for bacterial culture, and the result was MRSA. After 1 week, the infection was controlled, granulation edema subsided, and MRSA strains cultured in wound secretions disappeared. Skin grafting was carried out on the residual wound 3 1 day after admission, and there were still less than 3% residual wounds after operation. After wet dressing with compound staphylococcal enzyme again, the wound gradually closed and the patient was discharged after 42 days in hospital.
3 discussion
Burn patients are prone to MRSA infection, which is not only related to the characteristics of burn itself, but also related to the application of large doses of antibiotics [3]. MRSA has low affinity for β -lactam antibiotics, which is due to the existence of specific pbps on its outer membrane, as well as a variety of drug hydrolases and structural variations, making it resistant to most β -lactam antibiotics [3]. The results of drug sensitivity test showed that MRSA was insensitive to most antibiotics except vancomycin and norvancomycin. For the treatment of residual wound caused by MRSA infection, povidone iodine complex can be used, and the wound can scab after 2 ~ 3 days and heal within 1 week. You can also wash the wound with hydrogen peroxide solution, isotonic saline solution and bromogeramine solution in turn, and then spray or wet compress the wound with compound lysostaphin. For MRSA wounds complicated with other bacterial infections, besides spraying and wet dressing the wounds with compound lysostaphin, the rational application of antibiotics is also very important. In principle, effective antibiotics should be selected according to the results of drug sensitivity test. During the treatment, the results of bacterial culture were followed up to observe the changes of drug resistance. Local use should avoid systemic antibiotics as much as possible. In this group of typical cases, MRSA and Pseudomonas aeruginosa grew many times in the wound secretions of patients during hospitalization, and showed the phenomenon of "one growing and the other growing". Pseudomonas aeruginosa was sensitive to ofloxacin in the early stage and developed drug resistance in the later stage, so cefpiramide sodium was used for effective treatment. Once the burn wound secretion culture is diagnosed as MRSA infection, strict disinfection and isolation should be carried out immediately to avoid cross-infection in the hospital. Medical staff should wash their hands and wear disposable masks and hats before and after rounds and dressing changes. Disposable articles and dressing after dressing change should be burned separately, and the wound should be sutured as soon as possible.
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[1] Rong Xinzhou, Gong Zhiwei, Wu Yongheng, et al. Changes and drug resistance of burn wounds in recent five years. Journal of the First Military Medical University, 1999, 19(3):234-235.
[2] Chen Li, Xiong. Clinical study on antibacterial effect of lysostaphin on wound bud tissue. Journal of third military medical university, 28, 2006 (14):1517-1519.
Wang Lichun, Li Dajiang, Xiong Zhonghua, et al. Clinical and drug resistance analysis of Staphylococcus aureus nosocomial infection. Chinese journal of nosocomiology, 2008,18 (10):1485-1488.
Note: This article is excerpted from "Clinical Observation of Staphylococcal in Controlling the Infection of Methicillin-resistant Staphylococcus aureus on Burn Wounds" (Yang Xiong, Liu Fengbin, Liu Yang).