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.     

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.     

The use of bacitracin irrigation to prevent infection in postoperative skeletal wounds. An experimental study

In dogs, irrigation of contaminated osseous wounds with bacitracin eliminated clinical evidence of infection and significantly reduced the number of positive cultures and pathological evidence of infection when compared with dogs that received no treatment or irrigation with normal saline solution. The inocula contained more organisms than are introduced into a wound during an elective orthopaedic operation. The use of bacitracin in the prevention of postoperative Staphylococcus aureus infection of bone in humans may be justified.     

Synergy between Staphylococcus aureus and Pseudomonas aeruginosa in a rat model of complex orthopaedic wounds.

BACKGROUND: We observed an interaction in animals inoculated concomitantly with Staphylococcus aureus and Pseudomonas aeruginosa during a study of the efficacy of surfactants for disinfection of orthopaedic wounds. This led us to investigate whether synergy could be demonstrated between Staphylococcus aureus and Pseudomonas aeruginosa in a rat model of complex orthopaedic wounds. METHODS: A wire was implanted into the spinous process of a lumbar vertebra of Sprague-Dawley rats through a dorsal incision. Animals were divided into two groups: group one was inoculated with either Staphylococcus aureus or Pseudomonas aeruginosa, and group two received a polymicrobial inoculation with both test organisms in varying concentrations. After inoculation, the wounds were irrigated and closed. On postoperative day 14, all animals were killed and specimens from the wounds were cultured. The number of colony-forming units (CFU) of Staphylococcus aureus or Pseudomonas aeruginosa needed to cause infection in 50% of the animals (ID50) was determined with use of the Reed-Muench method. The infection rate associated with each inoculum combination was calculated, and the two groups were compared. RESULTS: The ID50 was 2.8 x 10(4) CFU for Staphylococcus aureus and 4.8 x 10(5) CFU for Pseudomonas aeruginosa. The combination of 10(3) CFU of Staphylococcus aureus with low concentrations (10(2), 10(3), or 10(4) CFU) of Pseudomonas aeruginosa yielded infection rates that were higher than those found with either organism alone at the same concentrations. The combination of 10(3) CFU of Staphylococcus aureus and 10(3) CFU of Pseudomonas aeruginosa yielded a 75% infection rate, which was significantly higher (p = 0.004) than that associated with 10(3) CFU of either organism alone. As the Pseudomonas aeruginosa concentration was increased (to 10(5), 10(6), and 10(7) CFU), this trend reversed, and the infection rate decreased to 33% (p = 0.004). Low concentrations of Pseudomonas aeruginosa (0 to 10(5) CFU) combined with 10(6) CFU of Staphylococcus aureus yielded infection rates ranging from 83% to 100%. At the higher concentrations of Pseudomonas aeruginosa (10(6) and 10(7) CFU), however, the infection rate again decreased, to 33% (p = 0.005). Only Staphylococcus aureus was isolated from the cultures of the specimens from the animals that had received a polymicrobial inoculum. CONCLUSIONS: Synergy between Staphylococcus aureus and Pseudomonas aeruginosa was demonstrated when low levels of each organism were present in the wound. As the Pseudomonas aeruginosa concentration was increased, the infection rates fell well below what would be anticipated, suggesting that low concentrations of Pseudomonas aeruginosa enhance the ability of Staphylococcus aureus to cause infection in this orthopaedic wound model. At the same time, the presence of Staphylococcus aureus in the ratios tested decreased the rate of infection by Pseudomonas aeruginosa. CLINICAL RELEVANCE: Staphylococcus aureus is a pathogen commonly seen in orthopaedic patients. The pathogenicity of Staphylococcus aureus was shown to be increased in the presence of anaerobic bacteria. This study is the first one that we are aware of that demonstrated synergy between Staphylococcus aureus and Pseudomonas aeruginosa, at low concentrations, in a wound model while at the same time showing that Staphylococcus aureus lowers the rate of Pseudomonas aeruginosa infection.     

Prevention of parietal septic complications by irrigation of the surgical wound]

In a randomized group of 162 patients, undergoing appendicectomy, irrigation of the wound with saline alone versus saline and antibiotics, shows a statistically significant smaller incidence of wound infection than in a comparative non irrigated group.     

Removal of surface bacteria by irrigation

We examined the efficacy of various irrigation solutions delivered through a power irrigator to remove bacteria from three different surfaces. Titanium, stainless-steel, and cortical bone surfaces were coated with three different bacterial species: Staphylococcus aureus, Pseudomonas aeruginosa, and Staphylococcus epidermidis. They were then irrigated with 1 L of fluid delivered by jet lavage. The fluids tested were normal saline and solutions of bacitracin, neomycin, and soap. One set of specimens was not irrigated, as a control. After irrigation, the specimens were sonicated to remove residual bacteria, and the sonicate was quantitatively cultured to allow evaluation of the amount of residual bacteria on the surface. The results showed that removal of bacteria reflects an interaction between bacterial species, surface characteristics, and irrigation solution. Fewer bacteria were present in all the irrigation groups than in the control. Soap solution was as good as or better than any other solution at removing all three types of bacteria from all three surfaces, although not all of the pairwise comparisons were statistically significant. There was a significant advantage to soap solution over antibiotic irrigant or saline alone in removing Staphylococcus epidermidis from metallic surfaces. The use of a soap solution for irrigation seems to improve the removal of some bacteria from some surfaces in this experimental model and may represent a better type of irrigation additive.     

The use of detergent irrigation for musculoskeletal wounds

The primary purpose of irrigation is to remove bacterial contaminants from the wound. Surfactants do that by disrupting the bonds of the organism to the surface. The use of this wound care strategy was studied in a series of investigations spanning several years. In vitro experiments revealed that surfactant irrigation was superior to saline or antibiotic solutions for removal of adherent bacteria from metallic surfaces, from bone, and from bovine muscle. An in vivo model of the complex orthopedic wound was developed. The superiority of surfactant irrigation over saline or antibiotic solution was demonstrated in animal wounds containing metal, bone injury, and soft tissue damage. Specificity of different surfactant irrigations for various bacterial species was demonstrated. A sequential surfactant irrigation protocol was developed and shown effective in the polymicrobial wound with established infection.     

The efficacy of function water (electrolyzed strong acid solution) on open heart surgery; postoperative mediastinitis due to methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) infection after cardiac surgery has recently increased. We compared the anti-inflammatory effect of an electrolyzed strong acid solution and a warm saline solution in patients with open heart surgery. These solutions were used for mediastinal irrigation before closing the sternum. Group A patients were irrigated by a warm saline solution, and group B patients were irrigated by an electrolyzed strong acid solution, administration of this water is safe, feasible, and easy for the prevention of MRSA infection. Postoperative infection was significantly decreased in the group B as compared in the group A. An electrolyzed strong acid solution may be effective on postoperative infection, particularly MRSA infection following open heart surgery.     

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.     

In vivo efficacy of antimicrobial-coated devices

BACKGROUND: Since device colonization is a prelude to infection, an antimicrobial-coated device that reduces bacterial colonization can potentially protect against infection. The objective of this animal study was to assess the efficacy of a coating with minocycline and rifampin to prevent colonization of a grit-blasted titanium implant and subsequent osteomyelitis. METHODS: Twenty-five rabbits underwent implantation of a titanium-alloy pin, either coated with minocycline and rifampin (thirteen rabbits) or uncoated (twelve rabbits), into the right femoral medullary canal. The implanted devices were inoculated with 500 CFU (colony-forming units) of Staphylococcus aureus prior to wound closure. The rabbits were killed one week later, and the removed device, femoral bone, a specimen obtained by swabbing the track surrounding the device, and blood were cultured. The rates of device colonization, osteomyelitis, and device-related osteomyelitis were compared between the two groups of rabbits. RESULTS: The antimicrobial-coated devices had a significantly lower rate of colonization than the uncoated devices (five of thirteen compared with twelve of twelve, p = 0.0016) and were associated with significantly lower rates of osteomyelitis (six of thirteen compared with twelve of twelve, p = 0.005) and device-related osteomyelitis (five of thirteen compared with twelve of twelve, p = 0.0016). Bacteremia did not develop in any rabbit. CONCLUSIONS: Orthopaedic devices coated with minocycline and rifampin significantly protected against device colonization and infection due to Staphylococcus aureus in this in vivo rabbit model. CLINICAL RELEVANCE: It is possible that orthopaedic devices coated with this unique combination of antimicrobial agents may protect against the development of clinical infection in humans.     

复方中药消毒剂消毒藻酸盐印模的应用价值

目的 探究复方中药消毒剂消毒藻酸盐印模的应用价值。方法 用制备好的个别托盘制取藻酸盐印 模,将印模分别放入浓度为108个/ml的金黄色葡萄球菌、白色念珠菌、大肠杆菌的菌悬液中浸泡染菌,再 将染菌后的藻酸盐印模分别浸泡于浓度0.25%、0.50%的亿人安消毒液、2000 mg/L的84消毒液中,分别浸 泡3、5、10、15 min。将消毒后的印模放入100 ml的0.90%生理盐水中浸泡3 min后取出,用倾注培养法对活 菌培养,并进行活菌计数。结果 3种消毒液在作用10 min与15 min时对金黄色葡萄球菌、白色念珠菌、大 肠杆菌的灭菌率为100.00%;在3 min与5 min时两种浓度的亿人安消毒液的灭菌率为97.62%~98.61%,84消 毒液的灭菌率为99.43%~99.64%。结论 0.25%浓度以上的亿人安消毒液浸泡藻酸盐印模10分钟以上对金黄 色葡萄球菌、白色念珠菌、大肠杆菌的灭菌率达到100.00%。     

Closure of abdominal incisions with subcutaneous catheters. A prospective randomized trial

A preliminary report from our institution suggested that closure of abdominal incisions with subcutaneous, closed-suction catheters intermittently irrigated with antibiotic resulted in decreased wound infection rates. To test this hypothesis, a prospective, randomized, controlled trial was undertaken to compare the results of primary closure, subcutaneous catheter irrigated with saline or antibiotic, and subcutaneous catheter alone. During the two-year trial, 3,282 incisions (type II, III, or IV) were analyzed. Subcutaneous catheter placement alone or with antibiotic or saline irrigation was not superior to primary closure for type II or III incisions. A trend favoring subcutaneous catheter and antibiotic irrigation was observed for type IV incisions. This finding suggests that further clinical trials designed to assess the role of subcutaneous catheter placement and antibiotic irrigation in decreasing wound infection rates are warranted in type IV incisions.     

Primary closure of deep sternal wound infection following open heart surgery: a safe operation?

BACKGROUND: Deep median sternotomy wound infection is a significant source of morbidity and mortality after cardiac operations. Management of an infected median sternotomy incision is a subject of controversy. The aim of this study was to assess our experience with primary closure without any irrigation system for infected deep median sternotomy wound. METHODS: Between January 1994 and December 1997, 4,227 consecutive open heart procedures via a median sternotomy under cardiopulmonary bypass were performed in our department. A total of 27 (0.64%) consecutive patients with deep sternotomy wound infection were identified. The mean age of the patients was 45 years. Six were female and 21 were male. RESULTS: The incidence of deep sternal wound infection was therefore 0.64%. The mean duration between the primary operation and the onset of deep sternal wound infection was 2.5 weeks. Staphylococcus aureus and Staphylococcus epidermidis were the most common pathogen causing postoperative mediastinal infection. Out of the 27 cases, 17 were successfully treated, 8 (30%) died and 2 had a persistent fistula. The mean follow-up time was 18 months (range 4 to 52 months). The mortality in the pediatric group was 4/8 (50%) and 4/19 (21%) in the adult group. The mortality for mediastinitis presenting before one week or after 4 weeks after operation was 63%. In contrast, the mortality for mediastinitis presenting after one week but before 4 weeks after operation was 17%. CONCLUSIONS: Mediastinitis after cardiac surgical procedures remains a devastating complication. Primary closure without irrigation-suction system should only be considered in selected patients.     

Role of internal fixation in infection of open fractures: studies with Staphylococcus aureus and Proteus mirabilis

Studies of infections in open fractures are described. The hamster was chosen as the experimental model. Osteotomies of the femur were created with an osteotomy saw. Some osteotomies were left to heal and others were fixed with an 0.9 mm K-wire. The infection rates in fixed and unfixed fractures were compared. The first group of hamsters with fixed and unfixed osteotomies was returned to cages with open wounds. There was no difference in the infection rate at 2 weeks. The second group was deliberately contaminated with Staphylococcus aureus and then returned to cages with open wounds. In this group, the infection rate at 2 weeks was lower in the internally-fixed fractures than in the unfixed fractures. The third group was deliberately contaminated with the gram negative organism Proteus mirabilis. In these animals, the infection rate was increased in the presence of the internal fixation device. The fourth group was deliberately contaminated with both Staphylococcus aureus and Proteus mirabilis. The infection rate in these animals was very high; Proteus was recovered from those animals with internal fixation and Staphylococcus was recovered from those animals without internal fixation. These studies in the hamster document the usefulness of this animal as an inexpensive and reproducible model for studying infection of open fractures. The hamsters tolerated the procedure well, and wound and fracture healing progressed satisfactorily.     

Evaluation of wound irrigation by pulsatile jet and conventional methods.

Irrigation of wounds to remove bacteria and foreign material is an essential of wound management along with debridement. The effectiveness of saline lavage by high pressure (50 psi) pulsatile jet irrigation has been compared with conventional gravity flow and bulb syringe procedures. Experimental paravertebral incisional surface wounds in 234 randomized rats were either clean or traumatized and soiled. Wounds in 200 of the rats were seeded with E. coli (log 8.80). Swab specimens of each wound were taken at incision, after seeding, after irrigation, and at three, seven, and ten days after closure. Eulates of more than 1600 specimens were cultured. No anaerobes were found. Irrigation diminished bacterial counts in all wounds, but only pulsatile jet irrigation brought about significant (P less than 0.05) reduction of bacteria in each type of wound. After three days E. coli was significantly diminished in all wounds, regardless of irrigation or none, owing to host defense mechanisms. Nevertheless, clean contaminated wounds were infected at three days but not at seven days after lavage, while traumatized wounds remained infected at ten days except for those initially irrigated by pulsatile jet. Thus, pulsatile jet irrigation removed bacterial from experimental wounds more efficiently than conventional procedures.     

Postoperative wound infection with methicillin-resistant staphylococci in general surgical patients

A prospective survey of 1757 general surgical patients undergoing operation was performed comparing 35 patients with wound infection yielding methicillin-resistant Staphylococcus aureus (MRSA) with 184 patients developing wound infections due to other organisms. The following parameters were statistically significantly increased in the patients with MRSA wound infection; MRSA infection or colonization at other sites, 37% versus 2%, severe wound infection 31% versus 12%, wound drain tubes 23% versus 10%, multiple operations 37% versus 6%, malignant disease 43% versus 23%, postoperative complications 46% versus 16%, intensive care admissions 23% versus 5% and prophylactic antibiotics 51% versus 30%. There was no difference in postoperative mortality 11% versus 7%; mean age, 58 years versus 56 years; sex; diabetes, 11% versus 9%; or emergency operations 40% versus 39%. There were 18 patients with single organism MRSA wound infection who were compared with 35 patients with single organism methicillin-sensitive S. aureus (MSSA) wound infection. The patients with MRSA wound infections had a statistically significant increase in the following parameters: mean preoperative stay in hospital 8 days versus 4 days; prophylactic antibiotics 39% versus 3%; MRSA infection or colonization at other sites 39% versus 6%; and malignant disease 44% versus 17%. There were no deaths in either group and there was no statistically significant difference in other parameters, namely, multiple operations 11% versus 3%; intensive care admissions 6% in each group; wound drain tube 17% versus 11%; severe infections 22% versus 6%; and postoperative complications 22% versus 9%. These latter parameters were statistically significantly increased when all MRSA wound infections were compared with all wound infections due to other organisms.     

Strategy to control methicillin-resistant Staphylococcus aureus post-operative infection in orthopaedic surgery

In the year 2000 the rate of infection after arthroplasty in our hospital was 9.75% and methicillin-resistant Staphylococcus aureus (MRSA) was the organism in 33% of the infected joints. In an attempt to overcome this unacceptable situation, we changed our prophylaxis regime over a period of 6 months. This involved modifying the precautionary measures for preventing surgical infections, active prophylaxis against any nasal reservoir of infection in joint implant patients, the control of health care personnel, the strict application of standard and contact precautions in all patients with MRSA, and the use of teicoplanin as prophylaxis during this 6-month period. This resulted in a definite decrease in the incidence of orthopaedic wound infections by MRSA, while the level of MRSA infection elsewhere in the hospital remained constant. Only one infection was detected during this 6-month trial, and this beneficial effect was maintained during the following 6 months. Since then, only sporadic new infections have been detected. Patients with arthroplasties performed during the study were followed for 12 months, and no new cases of MRSA infection were detected.     

Comparison of bulb syringe and pulsed lavage irrigation with use of a bioluminescent musculoskeletal wound model

BACKGROUND: Despite the fact that wound irrigation is a common surgical procedure, there are many variables, including delivery device, irrigant type, and fluid volume, that have yet to be optimized. The purpose of this study was to compare, with use of transgenic bioluminescent bacteria and standard quantitative microbiological methods, the efficacy of pulsed lavage and bulb syringe irrigation in reducing wound bacterial counts. METHODS: A caprine model of a complex, contaminated musculoskeletal wound was developed with use of a bioluminescent strain of Pseudomonas aeruginosa that can be quantified. Luminescent activity was recorded as relative luminescent units with use of a photon-counting camera six hours after the wound was created and inoculated. Twelve goats were randomly assigned to either the pulsed lavage group or the bulb syringe irrigation group. Each wound was irrigated with normal saline solution in 3-L increments for a total of 9 L and was imaged after each 3-L increment. In addition, quantitative culture samples were obtained from different tissues within the wound before and after irrigation. RESULTS: Pulsed lavage decreased the amount of relative luminescent units by 52%, 64%, and 70% at 3, 6, and 9 L, respectively. The bulb syringe irrigation reduced the amount of relative luminescent units by 33%, 44%, and 51% at these same time-points. Significant differences in luminescence were noted between the two groups after both 6 and 9 L of irrigation (p < or = 0.04). The correlation coefficients between relative luminescent units and quantitative cultures for the condition before irrigation and after irrigation were r = 0.96 and 0.83, respectively. CONCLUSIONS: Pulsed lavage was more effective than bulb syringe irrigation in reducing bacterial luminescence after both 6 and 9 L of irrigation. Both device and volume effects can be demonstrated with use of this model. Bioluminescent bacteria provide a method to visualize bacterial distribution and to quantify the bacteria in a wound. CLINICAL RELEVANCE: Pulsed lavage is a more effective and efficient method of irrigation to remove bacteria in a complex musculoskeletal wound. In the model we used, pulsed lavage irrigation with 3 L of saline solution resulted in a reduction of approximately the same amount of bacteria as did irrigation with 9 L with use of a bulb syringe.     

Outcome of infected total hip arthroplasty. An inclusive, consecutive series

Twenty-one infected total hip arthroplasties in 19 patients performed between 1971 and 1982 were prospectively followed, using a computerized standard orthopaedic arthritis record. These cases represent an inclusive and unselected, consecutive series. The mean follow-up period from time of infection was 4.8 years (range, 1.2-11.7 years). Infection was diagnosed by positive bacteriologic culture. Ten hips grew a staphylococcal species, 5 a single gram-negative organism, 1 a Streptococcus, and 5 multiple organisms. At final follow-up evaluation, only three hips (14%) had the previously infected prosthesis still in situ, and these had no evidence of ongoing deep infection. Five additional hips (24%) were successfully salvaged after one- or two-stage prosthetic exchange. Two hips (10%) have an infected prosthesis in situ. Eleven hips (52%) had resection arthroplasty, three after attempts at prosthetic reinsertion. Therefore, at final follow-up evaluation, only 8 of the 21 hips (38%) have an apparently infection-free salvaged or reinserted prosthesis in place. Good prognostic factors for prosthetic salvage/successful reinsertion include Staphylococcus epidermidis infection and a traumatic etiology necessitating later hip arthroplasty. Poor prognostic factors include infection with Staphylococcus aureus or multiple organisms and a preoperative diagnosis of avascular necrosis.     

胸腰椎后路内固定术后深部感染的治疗

目的 探讨胸腰椎后路内固定术后深部感染的特点与治疗方法。方法对36例胸腰椎内固定术后感染患者的临床表现、生化和细菌学检查及治疗进行分析。根据发生感染时间的不同分为早期感染14例,迟发性感染22例。结果早期感染一般伴有全身症状,白细胞计数及红细胞沉降率（ESR）升高,脓液培养主要为金色葡萄球菌、大肠杆菌等致病力强的细菌,迟发性感染一般无全身症状,白细胞计数不升高,ESR升高,脓液培养主要为类白喉杆菌、表皮葡萄球菌等致病菌力较弱的皮肤正常菌群。早期感染患者予以清创、持续冲洗引流。除3例反复清创无效,将内固定取出以外,其余内固定均予保留。迟发性感染者予以内固定取出、清创、持续冲洗引流。33例平均随访2．6年,经上述治疗后仅1例患者早期深部感染迁延不愈致椎体骨髓炎,术后3个月伤口再次出现流脓,其余均愈合。结论胸腰椎固定后早期感染及迟发性感染的发生机理可能存在差异。早期感染由致病力强的细菌引起,累及范围广。而迟发性感染由致病菌弱细菌引起,发展慢且较局限。对早期深部感染可以保留内固定行病灶清除,持续冲洗引流,多次清创无效,感染控制不佳则需要早日将内固定取出,以免炎症扩散。而迟发性感染则需取出内固定,否则难以消除炎症。