Comparison of castile soap, benzalkonium chloride, and bacitracin as irrigation solutions for complex contaminated orthopaedic wounds.

OBJECTIVE: The purpose of the present study was to determine the effects of cleaning a contaminated orthopaedic wound with different classes of wound irrigation solutions. STUDY DESIGN: Rats with a contaminated orthopaedic wound were randomized into treatment groups: normal saline (NS), castile soap (CS), benzalkonium chloride (BzC), bacitracin (Abx), or sequential irrigation with BzC, CS, and NS. INTERVENTION: Pseudomonas aeruginosa [P. aeruginosa; 1 x 10(6) colony-forming units (CFU)], or Staphylococcus aureus (S. aureus; 1 x 10(6) CFU) were placed into a paravertebral wound (containing a wire implant placed through a spinous process) and allowed to incubate for fifteen minutes. The wound was then irrigated with three liters of either NS, 0.05 percent CS, 0.03 percent BzC, Abx (33,000 units per liter) or underwent a sequential irrigation treatment (one liter each of BzC, CS, NS). MAIN OUTCOME MEASUREMENTS: The animals were observed daily for wound complications for fourteen days and then killed, and cultures of the wound were obtained. RESULTS: Pseudomonas aeruginosa: Both CS and the sequential irrigation treatment significantly lowered the rate of positive wound cultures when compared with NS (p < 0.05). Irrigation with BzC resulted in a higher rate of positive wound cultures and complications. The sequential irrigation treatment prevented the wound complications associated with irrigation with BzC alone. Staphylococcus aureus: Only BzC irrigation significantly lowered the rate of positive wound cultures when compared with NS (p < 0.05). CONCLUSION: The rate of positive wound cultures due to P. aeruginosa is effectively reduced by irrigation with CS alone or by the sequential irrigation treatment. When used alone, the antiseptic BzC results in a higher rate of positive wound cultures and wound complications. The wound complications seen with irrigation with BzC alone are prevented by the sequential irrigation treatment (BzC followed by CS and NS). The rate of positive wound cultures in this model due to S. aureus is not decreased by irrigation with CS; however, the rate of positive wound cultures is safely and effectively decreased with the use of BzC.     

Controlling methicillin resistant Staphyloccocus aureus and Pseudomonas aeruginosa wound infections with a novel biomaterial.

Wound infections, especially those associated with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, offer considerable challenges for clinicians. Our laboratory has recently developed novel composite biomaterials (DRDC) for wound dressing applications, and demonstrated their in vitro bactericidal efficacy. In the present study, we assessed the proliferation of planktonic and sessile Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus in porcine full-thickness wounds covered for up to 48 h with either saline- or mafenide acetate-loaded DRDC puffs and meshes. All biomaterials were applied 4 h following bacterial inoculation of the wounds with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, to allow colonization of the tissues and initiation of biofilm formation. The drug-loaded biomaterials eradicated both the planktonic and biofilm bacteria in the wounds within 24 h (p <. 05), irrespective of the bacterial strain or architecture of the dressing. While the wound bioburdens increased in the ensuing 24 h, they remained approximately 2 log(10) colony-forming units (CFU) below (p <. 05) their respective baseline values. Similarly, less than 4 log(10) CFU was recovered in the drug-loaded DRDC biomaterials throughout the study. These data show that the DRDC puffs and meshes are effective in delivering certain medications, such as antimicrobial agents, to the wound bed, suggesting considerable value of this material for treating wounds, especially those with irregular shapes, contours, and depths.     

Development of an experimental model of infected skin ulcer

A model of infected skin ulceration could prove useful in assessing the clinical effectiveness of antimicrobial ointments and dressings. However, no such models have been previously established. Three types of wound were induced in rats: full-thickness wounds covered with gauze, burn wounds and wounds resulting from mechanical trauma. Wounds were inoculated with S. aureus or P. aeruginosa. Persistent infected wounds were observed only in full-thickness wounds covered with gauze. In a second experiment, colonies of P. aeruginosa or S. aureus were counted within 15 x 15 mm full-thickness wounds covered with gauze. Wounds were inoculated with 1.0 x 10(6) colony-forming units (CFU) of P. aeruginosa or S. aureus and then sealed to ensure an enclosed environment. Tissue bacterial counts exceeded 10(6) CFU/g from the next day until day 9 after infection. Bacterial counts exceeded 10(8) CFU/ml in wound exudate collected between days 1 and 7. We have developed a model of wound infection in which persistence of infection can be achieved for 9 days following ulceration due to the application of gauze to the base of a full-thickness wound.     

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。     

An evaluation of the role of systemic antibiotic prophylaxis in the control of burn wound infection at the Lagos University Teaching Hospital

A prospective study was carried out on 61 patients to evaluate the role of systemic antibiotic prophylaxis in the control of burn wound infection. The patients were randomised into three groups: group 1 (n=21) received ampicillin and cloxacillin; group 2 (n=20) received erythromycin and genticin and a control group (n=20) received no systemic chemo prophylaxis. The burn wounds were similarly managed. Wound colonisation was determined from surface wound swab cultures and wound infection was determined from wound biopsy cultures and histopathology. The colonisation time (days) for the groups was 2.90+/-0.92, 3.15+/-0.77 and 3.05+/-0.83 for groups 1 and 2 and the control, respectively. The commonest organism isolated from contaminated wounds was Staphylococcus aureus. Wound infection was established in 5.70+/-1.70, 5.75+/-1.62 and 5.6+/-1.90 days for group 1, group 2 and the control group, respectively. There was no significant difference between wound infection time of control and group 1 nor was there such difference between the control and group 2 (P>0.05). The commonest organism infecting burn wounds in all the groups was Pseudomonas aeruginosa followed by S. aureus. There was however a significant difference between the treatment groups and the control (P<0.05) with regard to the percentage of infected wounds that grew P. aeruginosa, compared to those that grew S. aureus. It was concluded that systemic antibiotic prophylaxis is of no value in controlling burn wound sepsis, and might even favour the growth of P. aeruginosa in the burn wounds.     

Silicone gel including antimicrobial agent

Silicone gel sheets containing Ofloxacin (OFLX), that provide a continual drug delivery system from a wound dressing to the wound so as to prevent infection and to promote healing, are described. It was found that silicone gel sheets without added medication did not inhibit microbial growth but that gel sheets containing 0.02% and 0.2% of OFLX had a positive antimicrobial effect against Staphylococcus aureus and Pseudomonas aeruginosa in a dose-dependent fashion in vitro. Further, this antimicrobial efficacy was greatly increased in a silicone gel sheet that contained 0.02% of OFLX and an additional 10% of silicone oil. In animal experiments, a silicone gel sheet containing OFLX prevented microbiol growth and promoted rapid epithelialisation in wounds to which Staphylococcus aureus had been applied, whereas wounds covered only with OpSite all resulted in continued infection.     

湿润烧伤膏抗感染作用的实验研究

我们采用大鼠２０％Ⅲ度烫伤创面接种绿脓杆菌ＡＴＣＣ－２７８５３作为实验治疗模型，旨在评价湿润烧伤膏外用治疗烧伤的防治感染功效。于接种绿脓杆菌后１０分钟、８小时、２４小时和４８小时开始外用湿润烧伤膏治疗，并以１％的Ａｇ－ＳＤ霜，１．２％的Ａｇ－ＦＬＸ霜和基础霜剂作为对照。治疗４８小时后送血培养，痂下细菌计数及组织病理学检查，以此作为评价指标。４种外用药物在体外对绿脓杆菌，大肠杆菌和金黄色葡萄球菌做抑菌试验，结果表明，Ａｇ－ＦＬＸ抗菌作用和疗效最强，Ａｇ－ＳＤ次之，而湿润烧伤膏的各项指标和基础霜剂间差异无显著意义（Ｐ＞０．０５）。说明湿润烧伤膏在防治烧伤感染方面几乎没有作用。     

Combined use of topical and systemic antibiotics

An animal wound model was used to compare the effectiveness of topical and systemic antibiotics and to examine the validity of using a combined regimen of both routes of antibiotic delivery. Gross infection rates and wound bacterial concentrations were determined after contamination with Staphylococcus aureus or Escherichia coli. Both moderate (10(8) colony-forming units [CFU]) and heavy (10(12) CFU) contamination were studied for each organism. Following moderate contamination, topical and systemic antibiotics were equally effective in reducing both wound bacterial content and infection rate, but there was no benefit from the combined use of both modes of antibiotic delivery. An additive effect of the combined regimen was noted only when the level of wound contamination was heavy.     

骨科切口感染者创面病原菌分布及自噬相关蛋白表达

目的探究骨科切口感染者创面病原菌分布,并分析骨科切口感染者自噬相关蛋白微管结合轻链蛋白-3(LC-3)、自噬特异性基因-1(Beclin-1)和泛素结合蛋白(P62)表达水平。方法选择2014年5月至2017年8月于西安市第九医院治疗的276例骨科患者为研究对象,将40例正处于切口感染期患者作为观察组,分析其创面病原菌分布;另采用随机数字表法选取暴露表皮、暴露皮下组织及暴露肌肉骨骼中未感染36例患者纳入对照组,分析两组患者感染切口创面组织标本Beclin-1、LC-3和P62自噬相关蛋白表达水平。结果276例骨科患者中治疗后发生切口感染者40例,感染率为14.49%。40例切口感染者共检出病原菌67株,包括革兰阴性菌46株(68.66%),其中铜绿假单胞菌为18株,占比最高(26.87%),其次为大肠埃希菌11株(16.42%);革兰阳性菌19株(28.36%),凝固酶阴性葡萄球菌8株(11.94%),其次为金黄色葡萄球菌7株(10.45%);酵母样真菌2株(2.99%)。感染切口创面组织标本免疫组织化学结果显示,观察组患者LC-3和Beclin-1蛋白阳性表达率显著低于对照组,差异有统计学意义(χ^2=7.488、P=0.006,χ^2=11.800、P=0.001);P62蛋白阳性表达率显著高于对照组,差异有统计学意义(χ^2=13.511、P<0.001)。Western blot结果显示观察组患者LC-3和Beclin-1灰度值显著低于对照组,P62灰度值显著高于对照组,差异均有统计学意义(t=15.282、4.207、8.678,P均<0.001)。结论骨科切口感染者创面病原菌以革兰阴性菌的铜绿假单胞菌和大肠埃希菌为主,自噬相关蛋白LC-3、Beclin-1降低,P62升高,自噬水平降低,推测骨科切口感染与自噬相关蛋白表达存在密切相关性。     

The effect of local infection upon wound healing: an experimental study

Local infection was introduced into rat abdominal wounds using a 10(8) bacterial/ml inoculum. Three groups of infection were used: Staphylococcus aureus, Pseudomonas aeruginosa and a combination group of Escherichia coli and Proteus mirabilis. Infection was shown to delay healing as judged by bursting tests. Fibroblast proliferation was depressed at the wound edges but there was an increase in the total amount of hydroxyproline present. Small vessel angiogenesis was increased in areas of abscess formation but larger vessels were commonly blocked by thrombus or distorted by surrounding inflamed tissue. The possible causes of these effects are discussed.     

烧伤病区病原菌分布及其耐药性调查

目的了解烧伤病区病原菌分布特点及其耐药情况，为临床治疗提供参考。方法回顾性分析笔者单位烧伤病区348例住院患者的创面、血液、静脉导管、痰液、尿液及脓液等标本分离而得的菌株，统计其病原菌分布情况及耐药性。结果共检出464株病原菌，其中革兰阴性杆菌244株占52、6％、革兰阳性球菌188株占40．5％、真菌32株占6．9％。主要检出菌株为金黄色葡萄球菌、铜绿假单胞菌、鲍氏不动杆菌、大肠埃希菌。甲氧西林耐药金黄色葡萄球菌（MRSA）对环丙沙星、青霉素G、苯唑西林等的耐药率已达100、0％，只对万古霉素敏感。铜绿假单胞菌对头孢哌酮／舒巴坦、亚胺培南、头孢吡肟的耐药率分别为15、8％、36、8％、33、3％。结论金黄色葡萄球菌、铜绿假单胞菌、鲍氏不动杆菌、大肠埃希菌是烧伤病区感染的主要病原菌；金黄色葡萄球菌、鲍氏不动杆菌对抗生素的耐药率较高。     

FE复合酶防治烧伤后期肉芽创面感染的临床观察

目的观察FE复合酶控制烧伤后期肉芽创面常见耐药菌感染的作用。方法选取笔者单位烧伤患者30例,随机分为治疗组15例,将FE复合酶50 ml溶于等渗盐水0-150 ml中,使其终浓度为1-3 U/ml,用无菌纱布浸湿该液后湿敷创面,1-2次/d;对照组15例,用庆大霉素+ 等渗盐水纱布湿敷创面,1-2次/d。于用药前及用药后1-5 d取创面分泌物作细菌培养,检测两组患者创面的细菌种类及所用药物对创面细菌的敏感率;观察两组患者创面愈合时间及植皮术后3、5、 8、10、12 d的创面愈合率。结果两组患者创面细菌以铜绿假单胞菌、大肠杆菌、阴沟肠杆菌、甲氧西林耐药金黄色葡萄球菌(MRSA)为主。治疗组对MRSA、表皮葡萄球菌、腐生葡萄球菌、铜绿假单胞菌、大肠杆菌、阴沟肠杆菌的敏感率分别为93．8％、100．0％、100．0％、100．0％、100．O％、95．0％,高于对照组的17．6％、31．3％、28．6％、44．0％、33．3％、28.0％(P<0．01)。治疗组植皮术后创面愈合时间为(10．6±1．5)d,明显短于对照组[(15．3±1．7)d,P<0．01]。治疗组患者植皮术后各时相点创面愈合率均明显高于对照组(P<0．01),植皮术后10 d治疗组创面愈合率为(85．4±2．4)％,与对照组(51．3±1．5)％比较,差异有统计学意义(P<0．01)。结论 FE复合酶可以有效控制创面感染,提高烧伤后期感染创面植皮成功率。     

Laser irradiation effect on Staphylococcus aureus and Pseudomonas aeruginosa biofilms isolated from venous leg ulcer

Chronic wounds, including diabetic foot ulcers, pressure ulcers and venous leg ulcers, represent a significant cause of morbidity in developed countries, predominantly in older patients. The aetiology of these wounds is probably multifactorial, but the role of bacteria in their pathogenesis is still unclear. Moreover, the presence of bacterial biofilms has been considered an important factor responsible for wounds chronicity. We aimed to investigate the laser action as a possible biofilm eradicating strategy, in order to attempt an additional treatment to antibiotic therapy to improve wound healing. In this work, the effect of near-infrared (NIR) laser was evaluated on mono and polymicrobial biofilms produced by two pathogenic bacterial strains, Staphylococcus aureus PECHA10 and Pseudomonas aeruginosa PECHA9, both isolated from a chronic venous leg ulcer. Laser effect was assessed by biomass measurement, colony forming unit count and cell viability assay. It was shown that the laser treatment has not affected the biofilms biomass neither the cell viability, although a small disruptive action was observed in the structure of all biofilms tested. A reduction on cell growth was observed in S. aureus and in polymicrobial biofilms. This work represents an initial in vitro approach to study the influence of NIR laser treatment on bacterial biofilms in order to explain its potentially advantageous effects in the healing process of chronic infected wounds.     

Sequential irrigation with common detergents: a promising new method for decontaminating orthopedic wounds

This investigation sought to determine the capacity of irrigation solutions in decontaminating orthopedic wounds challenged with a polymicrobial inoculum. Rats were divided into two groups, a control group and a treatment group. After creation of a dorsolumbar incision and placement of a wire through the spinous process, rats were inoculated with Staphylococcus aureus and Pseudomonas aeruginosa. Wounds were irrigated with control or treated solutions. At 2 weeks, cultures were obtained. There were statistically significant differences between groups regarding total number of culture positive sites (P < 0.001), culture-positive animals (P = 0.02), and quantitative cultures (P < 0.02). Sequential irrigation with surfactants lowers bacteria counts recovered from polymicrobial wounds.     

An experimental study on pyogenic osteomyelitis with special reference to polymicrobial infections

The author used the following method to successfully devise a model of experimental osteomyelitis caused by two different bacteria. A 3-mm silk thread (No. 5) soaked in Staphylococcus aureus (1.0 X 10(4) CFU) and Pseudomonas aeruginosa (1.0 X 10(5) CFU) suspensions was dried under reduced pressure. The silk thread was inserted into the metaphysis of the right tibia of mice. Experimental osteomyelitis caused by these two species of bacteria was successfully produced in all the mice, and this infection was similar to osteomyelitis in man. After prior infection with S. aureus, P. aeruginosa (1.0 X 10(3) CFU) was inoculated directly into the tibia of mice during the acute and chronic stages of the S. aureus infection, and secondary infection by P. aeruginosa was confirmed in all the mice. Using this experimental model of osteomyelitis, the author administered an antibiotic that is effective against only S. aureus in mice and observed abrupt growth of P. aeruginosa to elucidate certain aspects of the bacterial replacement phenomena.     

Occlusive dressings. Does dressing type influence the growth of common bacterial pathogens?

We studied the effect of different occlusive dressings and of air exposure on the growth of four pathogenic bacteria in wounds. Partial-thickness wounds on domestic pigs were inoculated with Staphylococcus aureus, Clostridium perfringens, Bacteroides fragilis, or Pseudomonas aeruginosa. Each wound was covered with three dressings (DuoDERM, Opsite, or Vigilon), or left exposed to air. Groups of wounds were sampled at 24, 48, and 72 hours. Staphylococcus aureus reached high levels beneath all of the dressings and in the air-exposed wounds. The numbers of C perfringens and B fragilis were greatly reduced in the air-exposed wounds and slightly reduced in the Opsite-covered wounds. The numbers of P aeruginosa were greatest in the Opsite- and Vigilon-covered wounds. The results indicate that occlusive dressings are not indicated in wounds that clinically appear to be grossly contaminated or that may contain anaerobic organisms.     

Comparison of bacteria-retaining ability of absorbent wound dressings

Fibrous materials in some modern absorbent wound dressings have the ability to sequester and retain bacteria; however, this ability varies according to the nature of the fibres. We studied the bacterial retention capacity of alginate and carboxymethylcellulose dressings, using an infected skin ulcer model on the backs of rats. Wound surfaces were inoculated with either Staphylococcus aureus or Pseudomonas aeruginosa at a concentration of 1.5 x 10(6) colony-forming units per wound. AQUACEL; Hydrofiber;, Kaltostat; or Sorbsan; were applied to the contaminated wounds for 12 h. Each dressing was then divided into two pieces. Total viable bacterial count within the dressing was calculated using one piece, and bacterial count released from the dressing into physiological saline was determined using the other piece, enabling bacterial retention rate to be calculated. Bacterial counts in tissue were also determined. Each dressing was tested on each of 10 wounds contaminated with each bacterium. Statistical analyses were performed using one-way analysis of variance (ANOVA) for replicated measures combined with Duncan's multiple comparison test. AQUACEL; Hydrofiber; dressing was most effective in its ability to retain both Staphylococcus aureus and Pseudomonas aeruginosa (p < 0.05). Bacterial counts in tissue showed no significant change with respect to pathogen or the type of dressing used. It can be concluded that the bacterial retaining ability of AQUACEL; Hydrofiber; dressing was found to be significantly higher than that of alginate dressings in an infected animal wound model.     

Establishment of a vascular graft infection model in the sheep carotid artery

A study was performed to assess whether a model of vascular graft infection could be established in sheep carotid artery. Either a protein sealed Dacron or a polytetrafluoroethylene (PTFE) graft was used in 22 sheep while a control operation was performed on 4 animals. Staphylococcus aureus in concentrations of 10(2), 10(4), 10(6) or 10(8) colony-forming units (CFU) was inoculated into the wound before closure. No infection occurred with an inoculum of 10(2). The lowest concentration of organism producing infection was 10(4) for PTFE, 10(6) for Dacron and 10(8) for controls. Six of eleven Dacron grafts and seven of ten PTFE grafts became infected. The sheep carotid artery has proven a satisfactory model for studies of vascular graft infection.     

Surfactant wound irrigation for the treatment of staphylococcal clinical isolates

Deep wound infection involving an implanted biomaterial is a devastating complication in orthopaedic surgery. Two-thirds of such infections are monomicrobial and the most commonly isolated bacteria in human osteomyelitis and orthopaedic device infection are Staphylococcus aureus and Staphylococcus epidermidis. The purpose of the current study was to examine the effectiveness of the previously reported sequential surfactant irrigation protocol against human-isolated clinical strains of Staphylococcus aureus and Staphylococcus epidermidis in the rat model of orthopaedic implant contamination. The infectivity rate of human-isolated clinical strains of Staphylococcus aureus in a contaminated complex orthopaedic wound was reduced effectively by a sequential surfactant irrigation protocol. Also, in this model, the infectivity of Staphylococcus epidermidis was reduced by normal saline irrigation alone when compared with no irrigation. Therefore, the sequential surfactant irrigation protocol may represent an effective method of wound irrigation in monomicrobial Staphylococcus aureus orthopaedic implant contamination, and normal saline irrigation may suffice in cases of monomicrobial Staphylococcus epidermidis contamination. Additional studies are necessary to determine the clinical use of surfactant irrigation.