Silver dressings: their role in wound management

Dressings have a part to play in the management of wounds; whether they are sutured or open, usually chronic wounds of many aetiologies which are healing by secondary intention. They traditionally provide a moist wound environment, but this property has been extended through simple to complex, active dressings which can handle excessive exudate, aid in debridement, and promote disorganised, stalled healing. The control of infection remains a major challenge. Inappropriate antibiotic use risks allergy, toxicity and most importantly resistance, which is much reduced by the use of topical antiseptics (such as povidone iodine and chlorhexidine). The definition of what is an antimicrobial and the recognition of infection has proven difficult. Although silver has been recognised for centuries to inhibit infection its use in wound care is relatively recent. Evidence of the efficacy of the growing number of silver dressings in clinical trials, judged by the criteria of the Cochrane Collaboration, is lacking, but there are good indications for the use of silver dressings, to remove or reduce an increasing bioburden in burns and open wounds healing by secondary intention, or to act as a barrier against cross contamination of resistant organisms such as MRSA. More laboratory, and clinical data in particular, are needed to prove the value of the many silver dressings which are now available. Some confusion persists over the measurement of toxicity and antibacterial activity but all dressings provide an antibacterial action, involving several methods of delivery. Nanocrystalline technology appears to give the highest, sustained release of silver to a wound without clear risk of toxicity.     

我院耐甲氧西林金黄色葡萄球菌的耐药性及肠毒素分析

收集了我院1994年10月至1995年4月金黄色葡萄球菌100株,应用药敏试验法筛选 MR-SA,并检测其对12种抗生素的耐药性,计算 MIC_(50)和 MIC_(90)。应用乳胶凝集试验法,测定其肠毒素产生率。结果我院总的 MRSA 阳性率为60%,烧伤科的 MRSA 阳性率为67.4%,内科62.5%,骨科44.5%。MRSA 耐药性低于50%的有万古霉素(3.3%)、去甲万古霉素(5%)、丁胺卡那霉素(21.5%)3种。MR-SA 产肠毒素率为100%,其中产两种以上者占35%,而 MSSA 产肠毒素率仅为20%,其中产两种以上者占5%。     

LED蓝光照射治疗MRSA感染创面的临床研究

目的:探讨使用LED蓝光照射治疗MRSA感染创面的临床疗效。方法:2012年12月~2014年1月,笔者科室共收治11例MASA感染的难治创面患者,创面大小20cm×20cm~40cm×40cm。通过每日洗澡,双氧水冲洗,LED蓝光照射及碘伏换药治疗。结果:复查细菌培养均未检测出MRSA,创面均完全愈合。结论:LED蓝光照射治疗对MRSA感染创面有较好的临床效果。     

我院耐甲氧西林金黄色葡萄球菌的耐药性及肠毒素分析

收集了我院１９９４年１０月至１９９５年４月金黄色葡萄球菌１００株，应用药敏试验法筛选ＭＲ－ＳＡ，并检测其对１２种抗生素的耐药性，计算ＭＩＣ５０和ＭＩＣ９０。应用乳胶凝集试验法，测定其肠毒素产生率。结果我院总的ＭＲＳＡ阳性率为６０％，烧伤科的ＭＲＳＡ阳性率为６７．４％，内科６２．５％，骨科４４．５％。ＭＲＳＡ耐药性低于５０％的有万古霉素（３．３％）、去甲万古霉素（５％）、丁胺卡那霉素（２１．５％）３种。ＭＲ－ＳＡ产肠毒素率为１００％，其中产两种以上者占３５％，而ＭＳＳＡ产肠毒素率仅为２０％，其中产两种以上者占５％。     

Implementation of a methicillin-resistant Staphylococcus aureus (MRSA) prevention bundle results in decreased MRSA surgical site infections

Background

Methicillin-resistant Staphylococcus aureus (MRSA) surgical site infections (SSIs) increase morbidity and mortality. We examined the impact of the MRSA bundle on SSIs.

Methods

Data regarding the implementation of the MRSA bundle from 2007 to 2008 were obtained, including admission and discharge MRSA screenings, overall MRSA infections, and cardiac and orthopedic SSIs. Chi-square was used for all comparisons.

Results

A significant decrease in MRSA transmission from a 5.8 to 3.0 per 1,000 bed-days (P < .05) was found after implementation of the MRSA bundle. Overall MRSA nosocomial infections decreased from 2.0 to 1.0 per 1,000 bed-days (P = .016). There was a statistically significant decrease in overall SSIs (P < .05), with a 65% decrease in orthopaedic MRSA SSIs and 1% decrease in cardiac MRSA SSIs.

Conclusion

Our data demonstrate that successful implementation of the MRSA bundle significantly decreases MRSA transmission between patients, the overall number of nosocomial MRSA infections, and MRSA SSIs.     

MRSA in urology: a UK hospital experience

OBJECTIVE: Methicillin-resistant Staphylococcus aureus (MRSA) infection appears to be increasing, the UK has one of the worst MRSA rates in Europe. As urological patients are at high risk, the aim of this study was to determine the number of newly diagnosed cases of MRSA detected in a urology ward. PATIENTS AND METHODS: The urology department serves an annual local population of greater than 500,000 with 30 inpatient beds and a tertiary population of 1 million. Over a five year period, we retrospectively recorded all patients with a new diagnosis of MRSA. We also determined colonization site and if the diagnosis of MRSA was made in an elective surgical patient or a patient admitted as an emergency. RESULTS: The mean number of newly diagnosed cases of MRSA was 20.6 per year. The percentage of patients with a new diagnosis of MRSA was less than or equal to 1% per year with no significant difference of new cases of MRSA over five years. Emergency patients had a trend towards a mean higher rate of MRSA. The commonest site of MRSA colonization was from catheters (32%) and open wounds (18%). DISCUSSION: MRSA is of concern, as compared to methicillin-sensitive staphylococcus aureus, because it is associated with high rates of clinically relevant infection, increased hospital stay and cost, greater mortality and high vancomycin usage. Mandatory reporting has shown a steady increase in the number of cases of MRSA infection over the past four years. We found that the number of newly diagnosed cases of MRSA was low, at less than or equal to 1% of patients per year. Furthermore, the number of new cases of MRSA remained constant over five years suggesting low acquisition rates in a busy UK urology ward.     

The prevalence of methicillin resistant Staphylococcus aureus (MRSA) isolates with high-level mupirocin resistance from patients and personnel in a burn center

The rate of the MRSA strains, particularly at burn centers, is increasing worldwide. Detection of mupirocin resistance MRSA strains in the burn centers particularly from personnel will help to control these strains. For this purpose, a total of 116 Staphylococcus aureus isolates from the patients (burns) and personnel (nostrils) in Ahvaz Taleghani hospital (Iran) were investigated. The methicillin and mupirocin resistant isolates were detected by multiplex amplification of the mecA and ileS-2 genes. The mecA was found among 80% of isolates. The rates of mupirocin resistant strains among personnel and patients were 70% and 6%, respectively. The carriage rates of the S. aureus, MRSA and MRSA with high-level mupirocin resistance in the personnel were 40%, 34% and 28%, respectively. In conclusions, the high prevalence of MRSA strains in the patients showed the potential outbreak of the MRSA in the burn center and highlighted the need of antibiotic susceptibility monitoring of MRSA. Moreover being personnel as a main reservoir in terms of MRSA strains with high-level mupirocin resistance emphasizes the screening of the personnel in terms of the MRSA in the healthcare system especially in the burn center.     

Radiotherapy and wound healing

Radiotherapy is an invaluable weapon when treating cancer. However, the deleterious effects of radiation, both immediate and long-term, may have a significant effect on local tissues. Problematic wound healing in radiation-damaged tissue constitutes a major problem that is frequently overlooked during the management of patients who require radiotherapy, or have had radiotherapy in the past. Poor wound healing may lead to chronic ulceration, pain, secondary infection and psychological distress and compromise the outcome of general or reconstructive surgery. We discuss the pathophysiology of poor wound healing following radiotherapy, specific problems for radiation-damaged tissue and potential treatments to improve wound healing of irradiated tissues.     

Comparison of silver nylon wound dressing and silver sulfadiazine in partial burn wound therapy

The study aims to perform a comparative assessment of two types of burn wound treatment. To do the assessment, patients with partial thickness burn wounds with total body surface area <40% were simple randomised to treat with nanocrystalline silver nylon wound dressing or silver sulfadiazine cream. Efficacy of treatment, use of analgesics, number of wound dressing change, wound infection and final hospitalisation cost were evaluated. The study showed silver nylon wound dressing significantly reduced length of hospital stay, analgesic use, wound infection and inflammation compared with silver sulfadiazine.     

MRSA screening in the vascular day-case population

INTRODUCTION

The UK Government has prioritised methicillin-resistant Staphylococcus aureus (MRSA) screening and new operational guidance has instructed that all day-case surgical patients should be screened from April 2009. We sought to identify the number of MRSA-positive patients in the vascular day-case population over a 1-year period and to profile this cohort in terms of risk-factors for MRSA. We also sought to identify whether the new guidance from the Department of Health (DH) had resulted in increased screening rates.

PATIENTS AND METHODS

Electronic records and laboratory culture results were prospectively consulted to identify whether patients had been screened and if MRSA had been isolated. Consideration was given to whether any patients had a delayed discharge or subsequent admission with an MRSA-related complication.

RESULTS

Six patients (2.1%) screened MRSA-positive (DH estimate 7%); five were previously known to be MRSA-positive, therefore only 0.36% patients were newly-identified as MRSA-positive. The proportion of patients screened increased from 35% to 72.5% after April 2009, in accordance with DH guidance. Successful decolonisation was proved in two patients (33.3%).

CONCLUSIONS

There is dispute with several of the key assumptions behind the DH’s impact assessment justifying an expanded MRSA-screening policy. It is not cost-effective to screen all vascular day-case admissions. We recommend selective screening for patients previously identified as MRSA-positive, or considered high risk.     

骨科创面蜡样芽胞杆菌感染临床特点及耐药性分析

目的:探讨骨科创面蜡样芽胞杆菌感染情况、临床特点及耐药性分析,为临床诊断及合理用药提供依据。方法:分析我院自2011年10月至2012年6月临床标本中分离的20株蜡样芽胞杆菌感染的临床资料及实验室结果,其中男18例,女2例;年龄22~67岁,平均(47.30±11.16)岁;病程5~20 d。采用营养支持、清创及相应的抗菌药物治疗,蜡样芽胞杆菌感染时,患者贫血貌,低蛋白血症,伤口有污染史。同时与正常组比较,正常组男23例,女7例;平均年龄(45.20±15.05)岁。感染治疗前后通过病原菌培养、创面红肿或渗出情况检查来评估感染控制情况,采用纸片扩散法(K-B法)测定20种抗菌药物的药敏结果。结果:20株蜡样芽胞杆菌在骨科创面感染中检出,其中患者创面污染史16例,营养不良20例,开放性骨折20例,手术时间>3 h 15例;实验室检查总蛋白(49.94±8.24)g/L,白蛋白(29.54±5.45)g/L,血红蛋白(103.20±11.79)g/L,均低于正常组;而白细胞计数(8.35±2.31)×109/L,中性粒细胞绝对值(6.98±1.99)×109/L,超敏C反应蛋白(73.60±55.14)mg/L,肌酸激酶(900.10±1 259.12)IU/L,均高于与正常对照组。对青霉素、头孢唑啉、头孢呋辛、头孢他啶、头孢吡肟、复方新诺明、红霉素抑菌圈直径小于15 mm,表现耐药;对克林霉素、万古霉素、庆大霉素、环丙沙星、亚胺培南抑菌圈直径大于20 mm,对该菌有较高的敏感性。结论:免疫力低下、低蛋白血症同时伴有开放性创伤及污染性创面的骨科患者蜡样芽胞杆菌易感染,治疗应在补充白蛋白、对症支持治疗基础上选择敏感的抗菌药物。     

Prevalence of MRSA colonization in an adult urban Indian population undergoing orthopaedic surgery

IntroductionOrthopaedic surgery is technically demanding, implant dependant and expensive. Infection translates into a prolonged morbidity and long-term use of antibiotics. The most common organism involved in osteo-articular infections is Staphylococcus aureus, and colonizes the anterior nares of 25–30% of the population. Carriers are at higher risk for staphylococcal infections after invasive medical or surgical procedures. Prevalence of methicillin resistant Staphylococcus aureus (MRSA) has not been assessed in patients admitted for orthopaedic surgery in the Indian setting.AimTo assess the preoperative prevalence of MRSA colonization in adult patients undergoing orthopaedic surgery in urban India.Materials and methodsThis is a retrospective analysis of patients from 2009 to 2013. A total of 1550 patients admitted for orthopaedic surgery were preoperatively screened with nasal and axillary swabs for MRSA. Swab-positive patients were treated with intranasal mupirocin ointment for 3 days followed by a repeat swab. A record was made of hospitalization in the year prior to surgery and the occurrence of surgical site infection (SSI).ResultsA total of 690 males and 860 females had been screened for MRSA using an inexpensive kit costing 500 Indian rupees. For MRSA, 7/1550 (0.45%) nasal swabs were positive. No patient since 2009 has had a SSI with MRSA.ConclusionMRSA screening prior to orthopaedic surgery is a valuable and cost effective preoperative investigation even though the incidence is low. Mupirocin is effective in clearing MRSA from the nares and maybe used for 3 days to obtain elimination of the bacteria.     

烧伤患者难愈性创面多重耐药菌回顾性分析

目的分析烧伤外科病房难愈性创面多重耐药菌（MDRO）定植感染情况，为临床感染防控提供依据。 方法对2012年1月至2017年12月中国人民解放军海军第九〇五医院烧伤外科住院患者难愈性创面的细菌学资料进行调查，回顾性分析MDRO的分布、检出率及特殊耐药情况。 结果难愈性创面分离出270株MDRO，其中革兰阳性菌128株（47.41%），革兰阴性菌142株（52.59%）。居前5位的MDRO依次为金黄色葡萄球菌（125株）、铜绿假单胞菌（56株）、大肠埃希菌（30株）、肺炎克雷伯菌（19株）和鲍曼不动杆菌（18株）。MDRO平均检出率为77.14%，以上前5位MDRO检出率分别为88.65%、65.12%、90.91%、100.00%和90.00%。特殊耐药菌株中，耐甲氧西林金黄色葡萄球菌共118株，碳青霉烯类耐药的铜绿假单胞菌、鲍曼不动杆菌和肺炎克雷伯菌分别为42株、12株和5株。 结论烧伤外科病房难愈性创面MDRO分布广泛、检出率高，应采取有效的感染防控措施。     

HaiMed难愈性创面人工智能辅助系统在创面测量中的应用

目的评估HaiMed难愈性创面人工智能辅助系统在创面测量中的准确性及实用性。方法根据入选标准选取北京大学第三医院成形外科2019年1至8月诊治的慢性创面患者20例,男12例,女8例,年龄20~76岁,其中术后愈合不良创面9例,糖尿病足创面6例,压疮4例,肿瘤创面1例。分别采用传统的透明膜勾边法和HaiMed难愈性创面人工智能辅助系统对20例创面面积进行测量。对2组创面面积测量结果进行配对t检验,应用Spearman简单相关分析、Bland-Altman评价以及变异系数,对HaiMed系统的准确性、稳定性进行统计分析。P<0.05为差异有统计学意义。结果 HaiMed难愈性创面人工智能辅助系统与传统测量工具相比,在创面面积测量中差异无统计学意义(t=1.997,P=0.060),2种方法的Spearman相关系数r=0.998,两者一致性好。Bland-Altman评价示所有散点均落于95%一致性界限内,HaiMed系统准确性可靠。透明膜勾边法组变异系数最小0.41%,最大4.03%,平均1.67%;HaiMed组变异系数最小0.15%,最大2.31%,平均0.60%,HaiMed系统较传统测量方法有更高的稳定性。结论 HaiMed难愈性创面人工智能辅助系统测量创面面积准确性高、稳定性好,尤其对于浅表创面,可进行简便快捷的创面评估,是一套新型、可靠的创面测量工具。     

An Audit Demonstrating a Reduction in MRSA Infection in a Specialised Vascular Unit Resulting from a Change in Infection Control Protocol

INTRODUCTION: In 2003, 18% of all admissions to our vascular ward were colonised by MRSA, with an MRSA infection rate of 10.6%. Standard practice was to segregate patients with proven MRSA from the rest of the patient pool. After a prospective audit, regression analysis was used to identify factors that could stratify patients into high and low risk for MRSA colonisation. A change in isolation policy was introduced that segregated patients according to their risk of MRSA acquisition, and isolated all patients undergoing prosthetic vascular reconstruction. Antibiotic policy was also altered. This audit reports the impact of these changes on MRSA colonisation and infection rates. METHODS: The MRSA status of patients during 777 in-patient episodes was prospectively recorded during three time spans; period 1 (November 2002-April 2003) before the change in isolation and antibiotic policy and, periods 2 (August-December 2003) and 3 (October 2004-January 2005) after the change in policy. RESULTS: Hospital acquired MRSA colonisation was reduced from 10.6% in period 1, to 1.1 and 1.4% in periods 2 and 3, respectively (p<0.001). Similarly, MRSA infection rates fell from 10.6 to 2.9 and 0.9% over the same time frame (p<0.001). The most dramatic changes in MRSA infection rates occurred in patients undergoing aneurysm repair (MRSA infection 30.1% in period 1 vs. 3.9 and 2.9% in periods 2 and 3) and lower limb revascularization (31 vs. 0 vs. 4.2%). Stepwise regression analysis revealed that the system of isolation was a significant factor reducing MRSA infection and colonisation rates (p<0.001). CONCLUSIONS: These data demonstrate that a change in infection control policy can significantly reduce MRSA infection in a vascular unit.     

The Effect of G-CSF in an Experimental MRSA Graft Infection in Mice

Wound infection after prosthetic material implantation is a troublesome complication with an incidence of 2% to 10%. The effect of granulocyte colony-stimulating factor (G-CSF) was studied in an experimental methicillin-resistant Staphylococcus aureus (MRSA) graft infection model. Eighty adult mice were used. Under general anesthesia an abdominal incision of 2 cm in length was performed. A subcutaneous cavity of 2 × 2 cm in size was created. Polypropylene mesh pieces of 2 × 1 cm and MRSA solution of 0.1ml of 10⁸ CFU/mL were used. G-CSF was applied systemically or locally in a dosage of 0.02 MU/30 g body weight. There were 8 groups: group I, wound + MRSA; group II, wound + mesh + MRSA; group III, wound + mesh + MRSA + G-CSF (ip, 48 h before operation); group IV, wound + mesh + MRSA + G-CSF (ip, 24 h before operation); group V, wound + mesh + MRSA + G-CSF (locally, into the cavity); group VI, wound + mesh (incubated in G-CSF solution for 4 h) + MRSA; group VII, wound + mesh + MRSA + G-CSF, ip, 24 h from operation; and group VIII (positive control group), wound + mesh + MRSA + Teicoplanin (0.03 mg/30 g body weight, ip, 1/2 h before operation). Three days after, animals were killed and incisions were examined for possible infection or abscess formation and wound failure. Meshes were removed; after vortexing and dilution, samples were incubated with 5% agar media. Results of bacterial incubation were evaluated 24 h and 48 h later. There were symptoms of wound infection and abscess formation in all groups except group VIII. In group VIII, MRSA was isolated in 7 events with a colony count below 10³. Bacterial counts were above 10⁶ (10⁶–10⁸) in all other groups. Thus, it was observed that wound infection could be created with this model, but G-CSF could not prevent the development of wound infection, whether it was administered systemically or locally. Teicoplanin decreased the number of colony-forming units of MRSA, and prevents wound infection in this MRSA wound infection model.     

整形外科患者创面感染MRSA的感染率及对应治疗观察

目的:探讨整形外科创面感染的特点及复方新诺明对创面耐甲氧西林金黄色葡萄球菌感染的治疗作用。方法:2013年1月~12月,共收治70例慢性创面患者,其中12例MRSA感染,创面大小1.5cm×1.5cm~20cm×15cm,通过每日复方新诺明悬浮液进行治疗,观察临床疗效、细菌清除情况及不良反应。结果:治疗创面1周后MRSA转阴率83.3%,治疗2周后MRSA转阴率91.67%,未出现明显的不良反应。结论:整形外科慢性局部创面MRSA感染不能忽视,复方新诺明可作为治疗局部创面MRSA感染的首选局部用药。     

MRSA infections following colorectal surgery in an enhanced recovery programme

Aim The aim of this study was to evaluate the incidence of methicillin‐resistant Staphylococcus aureus (MRSA) infections in a cohort of patients undergoing elective colorectal resections within an enhanced recovery programme. Method A prospective database of all patients undergoing colorectal resections by a single surgical team over a 3.5‐year period was reviewed. Demographics including age, gender, body mass index, American Society of Anesthesiologists classification, type of surgery (abdominal or pelvic) and whether or not the procedure was laparoscopic or open were analysed. All patients were screened preoperatively and postoperatively and on discharge for MRSA. Patients found preoperatively to be MRSA positive were excluded from the study. Results In all, 186 patients underwent colorectal resection over the time reviewed. There were 113 laparoscopic resections, 70 open resections and three laparoscopic converted to open resections. Five patients (2.7%) were found to be MRSA positive postoperatively. All of these had open rather than laparoscopic surgery (P < 0.01). Length of stay for patients that had MRSA infections was significantly longer than those remaining MRSA free (P < 0.05). Conclusion These results suggest that patients who successfully undergo laparoscopic colorectal resections within an enhanced recovery programme have a lower incidence of postoperative MRSA infections.     

Role of macrophages in a mouse model of postoperative MRSA enteritis

BACKGROUND: We have established a mouse model for fatal postoperative enteritis due to Staphylococcus aureus to analyze mechanisms of bacterial translocation and determine reasons for the lethality of this infection. In the present study the role of macrophages was ascertained in protection against S. aureus induced enteritis. MATERIALS AND METHODS: Mice were pretreated with cyclophosphamide (CY), an immunosuppressant, and then infected directly into the jejunum with methicillin-resistant S. aureus (MRSA) isolated from a patient. In other groups of mice liposome-encapsulated dichloromethylene diphosphate (Cl2MDP) was administered to deplete macrophages in vivo. Other experimental groups received lipoteichoic acid (LTA), which was used to inhibit the ability of macrophages to bind MRSA, and additionally, to analyze dependence of bacterial clearance on the macrophage scavenger receptor. The ability of macrophages to bind MRSA was compared with survival rates in this mouse model of fatal postoperative enteritis. RESULTS: Injection of liposome-encapsulated Cl2MDP decreased survival rate of mice infected intraintestinally with MRSA in a dose-dependent manner. Cyclophosphamide also decreased survival rate of MRSA-infected mice and was found to correlate with its ability to decrease the number of macrophages in the spleen. Intravenous LTA administration did not affect total splenocyte numbers or the number of splenic macrophages but decreased the ability of macrophages to bind MRSA and adversely affected survival of mice infected with MRSA. CONCLUSIONS: Macrophages play a critical role in protection against MRSA administered directly into the jejunum. LTA recognition sites (probably type A scavenger receptors) on macrophages are required for binding and phagocytosing MRSA.