Tap water versus sterile saline solution in the colonisation of skin wounds

Irrigating wounds with tap water does not increase colonisation, but controlled studies are required for further evidence. Microbial colonisation was assessed in skin wounds, before and after irrigation with tap water, and was compared with irrigation using 0·9% sodium chloride sterile solution. The study included 120 subjects with chronic, traumatic, vascular, pressure or neuropathic wounds. A total of 60 wounds were randomly assigned to be irrigated with tap water (tap water group) and another 60 to be irrigated with 0·9% sodium chloride sterile solution (saline group), at a pressure of 0·46–0·54 PSI. Samples were collected from the centre of each wound using Levine's technique, before and after irrigation, and cultivated in thioglycollate, hypertonic mannitol agar, eosin methylene blue (EMB) agar, blood agar and Sabouraud agar at 37°C for 72 hours. There was concordance (kappa test) and discordance (McNemar test) regarding the count of positive and/or negative samples before and after irrigation in each group. The proportion of reduction of positive samples was similar for both groups in all cultures. Colony‐forming unit count before and after irrigation was similar in both groups and in all cultures, except for the culture in hypertonic mannitol agar from the tap water group, for which the count was lower after irrigation (Wilcoxon z = 2·05, P = 0·041). It is concluded that skin wound irrigation with tap water leads to further reduction of Gram‐positive bacteria compared with 0·9% sodium chloride sterile solution, with no difference in colonisation of haemolytic bacteria, Gram‐negative bacteria and fungi.     

Microbiological quality of hemodialysis water in a three-year multicenter study in Uruguay

BACKGROUND: The microbiological quality of treated water is a very important issue in hemodialysis (HD) centers. Water treatment may have a dramatic effect on microbial contamination because of bacterial colonisation of the different parts of the system such as storage tanks, softeners or deionisers. Therefore, HD centers must have stringent quality programmes including regular water monitoring for microbiological analysis. We report the results of a three-year study (July 97 to June 2000) including bacteriological quality analysis of 3129 water samples from 32 out of 38 HD centers throughout Uruguay. METHODS: Bacteriological analysis of water samples was based on heterotrophic count, total coliform count and Pseudomonas aeruginosa presence/absence, according to the procedures proposed by the Association for the Advancement of Medical Instrumentation (AAMI). RESULTS: Heterotrophic counts of 83% of the samples were under 200 colony forming units (CFU) /mL (AAMI limit of compliance) and the water samples after the final bactericidal treatment showed 99% compliance. The points showing the worst results were softeners and deionisers (60% acceptance). CONCLUSIONS: In comparison with a similar study in Uruguay, from January 96 to June 97 at the same microbiological laboratory, there has been a marked improvement in the microbiological quality of water for hemodialysis.     

Effectiveness of neomycin/polymyxin bladder irrigation to treat resistant urinary pathogens in those with spinal cord injury

Individuals with spinal cord injury (SCI) will sometimes develop bacterial organisms in the bladder that are resistant to oral antibiotics. This study evaluated the effectiveness of a 5-day course of intermittent neomycin/polymyxin bladder irrigation at eradicating or changing the bacterial sensitivity from parenteral to oral antibiotics. A chart review of individuals with SCI who were treated with neomycin/polymyxin bladder irrigations was performed. Inclusion criteria included the use of an indwelling catheter and the presence of asymptomatic bacteria resistant to oral antibiotics. The most common reason for treatment was eradication of resistant organisms prior to urologic testing. Bladder irrigation consisted of 3 rinses with 30 ml 3 times a day for 5 days. Pre- and post-urine samples were compared for white blood cells (WBCs), colony count and culture, and sensitivity. Chi-square tests were used to determine whether the proportion of changes in resistance or sensitivities was different from zero. The Wilcoxon Signed Rank Test was used to determine differences in bacteria, colony counts, and WBCs. Ten individuals were identified. A total of 12 neomycin/polymyxin irrigation treatments were evaluated because 2 individuals had a second series of irrigations at least 6 months apart. Nine of the 12 (75%) were considered to have successful irrigations because there was a change in culture sensitivity so that oral antibiotics would be effective post irrigation. This was statistically significant. There were no significant changes in colony counts or the number of WBCs. The authors concluded that while neomycin/polymyxin bladder irrigation did not change the type of organism, it was effective in changing resistance of most organisms. Individuals could then be treated with oral rather than intravenous or intramuscular antibiotics. Further work is needed to determine whether other variables, such as increased length of time of irrigation or increased frequency of irrigations, may actually eradicate the organisms.     

Prevention of biofilm formation in dialysis water treatment systems

BACKGROUND: Biofilm formations in dialysis systems may be relevant because they continuously release bacterial compounds and are resistant against disinfection. The aim of the study was to compare the development of biofilm between a water treatment system based on a single reverse osmosis unit producing purified dialysate water [bacterial count, 350 colony-forming unit (CFU)/L] (center A) and a water treatment system based on double reverse osmosis and electric deionization, which is continuously disinfected with ultraviolet light and treated with ozone once a week (bacterial count, 1 CFU/L) (center B). METHODS: During a period of 12 weeks, biofilm formation was studied in the tubing segment between the water piping and the dialysis module, using four dialysis monitors in each center. On a weekly basis, tubing samples of 5 cm length (N = 96) were taken under aseptic conditions and investigated for microbiologic contamination [cystine lactose electrolyte-deficient (CLED) Agar], endotoxin levels [limulus amoeben lysate (LAL) gel test, cutoff value, 0.0125 EU/mL], and biofilm formation [electron scanning microscopy (SEM)]. RESULTS: In center A, tube cultures were positive (>100 CFU/mL) in 16% of samples at 22 degrees C and 37 degrees C, compared to 3% of samples of center B (P < 0.05; chi-square). Endotoxin levels were positive in 76% of the tubing samples of center A and negative in all of the samples of center B (P < 0.05). Biofilm was present in 91.7% of the samples of center A (Fig. 1), and only present in one sample (taken after 9 weeks) of center B (P < 0.05) (Fig. 2). In center A, biofilm formation was already observed after 1 week. CONCLUSION: In contrast to a standard water treatment system producing purified water, the use of a system producing highly purified water, which is also treated with regular disinfection procedures, leads to a significant reduction in biofilm formation, bacterial growth, and endotoxin levels in a highly vulnerable part of a water treatment system.     

Automated flow cytometry analysis of peritoneal dialysis fluid.

BACKGROUND: Recently, the Sysmex UF-100 flow cytometer has been developed to automate urinalysis. We have evaluated this instrument to explore the possibilities of flow cytometry in the analysis of peritoneal dialysis fluid (PD) and have compared the obtained data with those of counting chamber techniques, biochemical analysis and bacterial culture. METHODS: UF-100 data were correlated with microscopy and biochemical data in 135 PD samples. Microbiological analysis was performed in 63 suspected cases of peritonitis. RESULTS: Good agreement (P < 0.001) was obtained between UF-100 and microscopy data for leukocytes (r = 0.825). UF-100 bacterial count correlated (P < 0.001) with UF-100 leukocyte count (r = 0.549). UF-100 bacterial counts were unreliable in samples where interference by blood platelets was observed. Another major problem was the UF-100 'bacterial' background signal in sterile PD samples. Yeast cells were detected by the flow cytometer in spiked samples. CONCLUSIONS: Flow cytometry of PD with the UF-100 offers a rapid and reliable leukocyte count. Sensitivity of the 'bacterial' channel count in predicting positive culture exceeds the sensitivity of conventional Gram stain. Furthermore, additional semi-quantitative information is provided regarding the presence of yeasts.     

Effectiveness of Neomycin/Polymyxin Bladder Irrigation to Treat Resistant Urinary Pathogens in Those with Spinal Cord Injury

Abstract

Individuals with spinal cord injury (SCI) will sometimes develop bacterial organisms in the bladder that are resistant to oral antibotics. This study evaluated the effectiveness of a 5-day course of intermittent neomycin/polymyxin bladder irrigation at eradicating or changing the bacterial sensitivity from parenteral to oral antibiotics. A chart review of individuals with SCI who were treated with neomycin/polymyxin bladder irrigations was performed. Inclusion criteria included the use of an indwelling catheter and the presence of asymptomatic bacteria resistant to oral antibiotics. The most common reason for treatment was eradication of resistant organisms prior to urologic testing. Bladder irrigation consisted of 3 rinses with 30 ml 3 times a day for 5 days. Pre- and post-urine samples were compared for white blood cells (WBCs), colony count and culture, and sensitivity. Chi-square tests were used to determine whether the proportion of changes in resistance or sensitivities was different from zero. The Wilcoxon Signed Rank Test was used to determine differences in bacteria, colony counts, and WBCs. Ten individuals were identified. A total of 12 neomycin/polymyxin irrigation treatments were evaluated because 2 individuals had a second series of irrigations at least 6 months apart. Nine of the 12 (75%) were considered to have successful irrigations because there was a change in culture sensitivity so that oral antibiotics would be effective post irrigation. This was statistically significant. There were no significant changes in colony counts or the number of WBCs. The authors concluded that while neomycin/polymyxin bladder irrigation did not change the type of organism, it was effective in changing resistance of most organisms. Individuals could then be treated with oral rather than intravenous or intramuscular antibiotics. Further work is needed to determine whether other variables, such as increased length of time of irrigation or increased frequency of irrigations, may actually eradicate the organisms.     

Impact of negative‐pressure wound therapy on bacterial behaviour and bioburden in a contaminated full‐thickness wound

The use of negative‐pressure wound therapy (NPWT) has displayed significant clinical benefits in the healing of infected wounds. However, the effects of NPWT on bacterial colonisation and infection of traumatic wounds has been controversial. The aim of this study is to evaluate the impact of NPWT treatment in rabbits with a contaminated full‐thickness wound on bacterial behaviour, including colony morphology, spatial distribution, fissional proliferation, and bacterial bioburden. Full‐thickness wounds were created on the back of rabbits, and were inoculated with bioluminescent Staphylococcus aureus. The wounds were treated with sterile gauze dressings and NPWT with continuous negative pressure (−125 mm Hg). Wound samples were harvested on days 0 (6 hours after bacterial inoculation), 2, 4, 6, and 8 at the centre of wound beds before irrigation. Scanning electron microscopy and transmission electron microscopy (TEM) analyses were performed to determine the characteristic bacteriology. Laser scanning confocal microscopy was performed to obtain bioluminescent images, which were used to observe spatial distribution of the GFP‐labelled S. aureus within the tissue and quantify the bacterial bioburden. NPWT resulted in sparse amounts of scattered bacteria on the wound surface or as sparsely spaced single colonies within the tissue. Wound bioburden on day 8 in the NPWT and gauze groups was 34.6 ± 5.5% and 141.9 ± 15.4% of the baseline values (N = 6), respectively (P < .0001). TEM showed a lack of S. aureus active fission within NPWT‐treated tissue. NPWT can impact S. aureus colony morphology and spatial distribution both on the surface and within wound tissue, and reduce S. aureus as early as 48 hours after therapy initiation. Additionally, NPWT inhibits bacterial fissional proliferation in microcolonies.     

Comparison between sterile saline and tap water for the cleaning of acute traumatic soft tissue wounds.

OBJECTIVE--To find out if there were any differences in infection rates if acute traumatic soft tissue wounds were cleaned with tap water instead of sterile saline. DESIGN--Randomised study. SETTING--Emergency department at one city hospital. SUBJECTS--705 consecutive patient with soft tissue wounds less than six hours old that did not penetrate a viscus, cavity, or joint and could be treated by primary suture. INTERVENTIONS--Randomly allocated to have the wound cleaned with either sterile saline or tap water in addition to debridement. MAIN OUTCOME MEASURE--Rate of wound infection, the presence of which was indicated by pus in the wound and prolonged healing. RESULTS--The infection rate in wounds cleaned with sterile saline was 10.3% compared with 5.4% in wounds cleaned with tap water (p less than 0.05). Infected wounds were significantly larger than uninfected ones (p less than 0.05) and more likely to be located on a lower extremity (p less than 0.05). There were no microbiological differences between the two groups, and no bacterial species grown from tap water was subsequently grown from an infected wound. CONCLUSION--Sterile saline should be replaced by tap water for the cleaning of acute traumatic superficial soft tissue wounds.     

Locally administered antibiotics for prophylaxis against surgical wound infection. An in vivo study

BACKGROUND: Currently, the standard for prophylaxis against surgical infection consists of perioperative systemic antibiotics. In this study, we investigated the relative efficacy of various methods of antibiotic delivery for the prevention of surgical wound infections. We hypothesized that sustained release of local antibiotics inside the wound cavity by a drug delivery system would be more effective than systemically administered antibiotics. METHODS: Using a rat model, we inoculated a surgical wound in the quadriceps muscle with 8.0 x 10(5) colony-forming units of Staphylococcus aureus and then administered one of seven types of treatment: no treatment (control), bacitracin irrigation, calcium sulfate flakes, systemic gentamicin, local aqueous gentamicin, local gentamicin-loaded calcium sulfate flakes, and a combination of local gentamicin-loaded calcium sulfate and systemic gentamicin. The seven treatment groups consisted of ten rats each. To further evaluate a trend, the group treated with systemic gentamicin and the one treated with local gentamicin solution were extended to include twenty-five and twenty-seven rats, respectively. At forty-eight hours postoperatively, specimens from the wounds were obtained for quantitative culture. RESULTS: The control group, the group treated with bacitracin irrigation, and the one treated with plain calcium sulfate had very high bacterial counts and high mortality rates while the groups treated with gentamicin had low bacterial counts and a 100% survival rate. Local gentamicin was significantly more effective than systemic gentamicin in reducing bacterial counts. CONCLUSIONS: The gentamicin-loaded calcium sulfate flakes did not result in bacterial counts that were significantly lower than those following systemic administration of gentamicin, which refuted our hypothesis. However, gentamicin solution injected directly into the closed wound did result in levels of bacteria that were significantly lower than those following treatment with the systemic gentamicin.     

Glove and instrument changing to prevent bacterial contamination in infected wound debridement and closure procedures: A prospective observational study

Many surgeons use a single table of instruments for both excisional debridement and coverage/closure of infected wounds. This study investigates the effectiveness of a two‐table set‐up of sterile instruments, in addition to glove exchange, to reduce instrument cross‐contamination during these procedures. This is a prospective, single‐site, institutional review board‐approved observational study of surgical debridements of infected wounds over a 17‐month period. Two separate sterile surgical tables were used for each case: Table A for initial wound debridement (debridement set‐up) and Table B for wound coverage/closure (clean set‐up). Swabs of each table and its respective instruments were taken after debridement but prior to coverage/closure. The primary outcome of interest was bacterial growth at 48 hours. There were 72 surgical cases included in this study. Culture results of Table A demonstrated bacterial growth in 23 of 72 (32%) cases at 48 hours compared with 5of 72 (7%) from Table B (P = .001). These data suggest that there is significant bacterial contamination of surgical instruments used for debridement of infected wounds. Use of a two‐table set‐up reduced instrument cross‐contamination by 78%, suggesting avoidable re‐contamination of the wound.     

Early wound irrigation improves the ability to remove bacteria

BACKGROUND: Although most surgeons prefer to treat contaminated wounds as soon as possible, the effect of timing on the ability of irrigation to reduce the amount of bacteria in a wound is not fully known. We evaluated the effect of different delays in irrigation on bacterial removal in an animal model. METHODS: A complex musculoskeletal wound was created in the proximal part of the leg of goats. The wound was contaminated with Pseudomonas aeruginosa (lux) bacteria, genetically modified to emit photons, in order to allow for quantitative analysis of bacterial concentration with a photon-counting camera system. The contaminated wounds were closed, and wound irrigation was performed with 6 L of normal saline solution by means of pulsatile lavage after the assigned time-intervals of three, six, and twelve hours. Images were made before and after treatment. Relative luminescent units and clearance ratios were obtained and calculated for each wound. RESULTS: Earlier wound irrigation resulted in superior bacterial removal in our model. Irrigation resulted in a 70% +/- 2%, 52% +/- 3%, and 37% +/- 4% reduction in bacterial counts from the pre-irrigation level at three, six, and twelve hours, respectively. The clearance ratios were significantly different at all time-points (p < 0.004). CONCLUSIONS: Earlier irrigation in our contaminated wound model resulted in superior bacterial removal.     

多发性压力性溃疡的外科治疗

目的 总结多发性压力性溃疡的治疗经验. 方法 2001年1月-2007年5月,笔者应用多种皮瓣转移联合皮肤移植治疗21例患者的56处压力性溃疡创面,其中骶尾部21处、坐骨结节14处、股骨大转子部13处、其他部位8处.围手术期行全身支持治疗,尽早清创,依据扩创后创面大小、深度、部位及邻近皮肤软组织条件,选用皮瓣、肌皮瓣或游离植皮修复创面.术后对伤口行连续灌洗与负压吸引,卧翻身床定期翻身. 结果 25处创面以筋膜皮瓣或肌皮瓣修复,愈合率为92%;13处创面以邻近局部皮瓣修复,愈合率为85%;8处创面直接缝合,其中6处一次性愈合;10处创面游离植皮,其中7处一次性愈合.在延期愈合的创面中,4处经再次清创缝合或植皮愈合,4处经短期换药愈合,1例遗留慢性窦道.随访6个月时,3例患者复发压力性溃疡. 结论加强围手术期全身支持治疗,合理、有效地利用臀部及其周围健康组织形成多个筋膜皮瓣或肌皮瓣同时修复多个创面,术后对伤口行连续灌洗与负压吸引,采用翻身床定期翻身等等,是多发性压力性溃疡手术成功的有效措施.     

Negative pressure wound therapy with instillation and dwell time (NPWTi‐d) with V. A. C. VeraFlo in traumatic,surgical, and chronic wounds—A helpful tool for decontamination and to prepare successful reconstruction

For nearly two decades, Negative Pressure Wound Therapy (NPWT) has been used for temporary wound coverage as well as wound bed preparation. The addition of instillation and dwell time as an adjunct to NPWT (NPWTi‐d) enables wound bed cleaning and improved wound bed granulation. Thirty patients with different types of colonised wounds (traumatic, surgical, and chronic) were treated with NPWTi‐d using saline for instillation. Patient data, microbiological data and wound characteristics were collected and analysed. Endpoints were bacterial decontamination (count and type), effect on wound bed granulation, and successful reconstruction. Additionally, subgroup analyses for traumatic, surgical, and chronic wounds as well as patients pretreated with conventional NPWT or isolated gram‐positive or negative germs were performed. NPWTi‐d was applied on average for 13 days with a total hospitalisation time of 51 days. After NPWTi‐d, decontaminated wounds were detected in 23% of cases. The number of different bacteria as well as bacterial count could be significantly reduced from 2.38 to 1.16 and 3.9 to 1.3, respectively. This was similar for all subgroups except surgical wounds, in which NPWTi‐d did not lead to a significant reduction of the bacterial count. NPWTi‐d resulted in a significant stimulation of granulation tissue. Successful reconstruction was achieved in 90% of cases. NPWTi‐d enabled wound pre‐conditioning by powerfully reducing or decontaminating the bacterial load and spectrum in most of the wounds. The wound bed integrity was re‐established to prepare successful reconstruction.     

The efficacy of photon-initiated photoacoustic streaming and sonic-activated irrigation combined with QMiX solution or sodium hypochlorite against intracanal <Emphasis Type="Italic">E. faecalis</Emphasis> biofilm

The aim of the study was to assess the antibacterial efficacy of photon-initiated photoacoustic streaming (PIPS) using an Er:YAG laser and sonic-activated irrigation combined with QMiX irrigant or sodium hypochlorite against Enterococcus faecalis intracanal biofilm. Root canals of 91 human extracted single-canal teeth were instrumented, sterilized, contaminated with E. faecalis and incubated for 15 days. The infected teeth were then randomly distributed into six experimental groups: G1: PIPS/Er:YAG laser (wavelength 2940 nm, pulse energy 20 mJ, 15 Hz, pulse duration 50 μs, energy density 2.06 J/cm², 3?×?20 s) with the QMiX irrigant; G2: PIPS/Er:YAG laser-activated 2.5 % NaOCl; G3 sonic-activated irrigation (EndoActivator system) for 60 s with the QMiX irrigant; G4 sonic-activated irrigation for 60 s with 2.5 % NaOCl; G5 30-gauge needle irrigation with the QMiX irrigant; G6 30-gauge needle irrigation with 2.5 % NaOCl. The positive control group was rinsed with sterile saline solution. The root canals were sampled by flushing with saline solution at baseline and after the treatments, serially diluted and cultured. The number of bacteria in each canal was determined by plate count. The presence and the absence of E. faecalis in root canals were demonstrated by polymerase chain reaction (PCR), and the pattern of the bacteria colonization was visualized by scanning electron microscopy. There was significant reduction in the bacterial population for all groups (p?<?0.001). The best antibacterial efficacy was recorded after sonic-activated irrigation with both NaOCl (99.999 %) and QMiX (99.999 %) and after PIPS with QMiX (99.999 %), which were more effective than conventional irrigation with NaOCl (99.998 %) and the PIPS with the NaOCl (99.966 %). Also, the PIPS with QMiX solution provided the highest number of sterile samples (five). There was no difference in the bacteria reduction between the active irrigation techniques, regardless of the irrigant used. Although the laser activation did not improve the antimicrobial action of the NaOCl nor QMiX, the fact that it generated the greatest number of sterile samples warrants further investigation.     

Management of soft tissue injury.

The fate of a surgical wound is held in a delicate balance between the host's resistance to infection and the causal factors of infection. Considerable insight into this relationship between the host and pathogen can be gained from the results of quantitative bacteriologic measurements. Newer rapid slide techniques have been developed which provide the surgeon with this information within 20 minutes. In most soft tissue injuries, the wound bacterial count gives an accurate prediction of subsequent infection. Wounds combining greater than 10(5) bacteria per gram of tissue are destined to develop infection. When the bacterial count is below that level, the wounds will usually heal per primam without infection. This large number of bacteria required to elicit infection reflects the remarkable ability of soft tissues to resist infection. This state of high resistance to infection can be reduced by several factors which include circulatory embarrassment, tissue injury, dead space, and the presence of foreign bodies (dirt, sutures, drains, etc.). When treating soft tissue injuries, the surgeon must employ specific therapeutic modalities that allow the wound to heal per primam without infection. On the basis of experimental studies supported by clinical experience, the following treatment protocol for soft tissue injuries is recommended. Using strict aseptic technique, the wound must be first anesthetized with 1 per cent Xylocaine to permit painless sound cleansing. All wounds should be subjected to high pressure syringe irrigation to remove bacteria, foreign bodies, and blood clots. When necessary, debridement of all devitalized tissue should be performed with a stainless steel scalpel. Many wounds caused by sharp wounding agents contain no foreign bodies and few bacteria and exhibit considerable resistance to infection. In these wounds, primary closure can be initiated after irrigation without the development of infection. Wounds resulting from impact forces have a diminished resistance to infection and are susceptible to infection by low level of bacterial contamination. Immediate antibiotic treatment of patients with impact injuries subjected to meticulous debridement and cleansing will permit a safe primary closure. In wounds contacted by pus or feces, open wound management followed by delayed primary closure is usually indicated. Antimicrobial prophylaxis is also recommended for patients with such wounds. Ideal postoperative care of all traumatic wounds includes a surgical dressing and immobilization and elevation of the site of injury.     

Focused high-energy extracorporeal shockwaves as supplemental treatment in a rabbit model of fracture-related infection

Focused high-energy extracorporeal shockwave therapy (fhESWT) is used to improve fracture healing in cases of nonunion. In addition, it has been shown to have direct antibacterial effects. We evaluated fhESWT as an adjunct to conventional treatment in a clinically relevant rabbit model of fracture-related infection (FRI). A humeral osteotomy in 31 rabbits was fixed with a seven-hole locking compression plate. FRI was established with a clinical Staphylococcus aureus isolate. After 2 weeks, a revision surgery was performed with debridement, irrigation, and implant retention. Rabbits then received: no further treatment (controls); shockwaves (4000 impulses with 23 kV at days 2 and 6 after revision); systemic antibiotics (rifampin and nafcillin); or the combination of antibiotics and shockwaves. Treatments were applied over 1 week. Blood cultures were taken before and after shockwave sessions. After another week without treatment, rabbits were euthanized and quantitative bacteriology was performed on implants and tissues to determine infection burden. Indicator organs (brain, heart, liver, lungs, kidneys, and spleen) were cultured to assess possible bacteremia. All the rabbits were infected at revision surgery as determined by the bacteriological culture of debrided materials. fhESWT in combination with antibiotic treatment lowered the bacterial burden 100-fold compared with antibiotic treatment alone in all samples (P = .38). This effect was most prevalent for the implant sample (P = .08). No significant effect was seen for fhESWT alone compared with untreated controls. No signs of bacteremia occurred in blood cultures and organs. fhESWT appears safe and could be a helpful adjunct to conventional treatment in certain difficult-to-treat FRIs.     

Bacterial adherence to surgical sutures: can antibacterial-coated sutures reduce the risk of microbial contamination?

BACKGROUND: Surgical site infections are associated with severe morbidity and mortality. The role of surgical sutures in the etiology of surgical site infection has been the objective of discussion for decades. This study used a standardized in vitro microbiologic model to assess bacterial adherence and the antibacterial activity of a triclosan-coated polyglactin 910 (braided) suture against selected Gram-positive and Gram-negative clinical isolates that may infect surgical wounds. STUDY DESIGN: Standardized cultures (2.0 log(10) colony forming units/mL and 5.0 log(10) colony forming units/mL of three clinical strains, Staphyllococcus aureus (methicillin-resistant S aureus [MRSA]), S epidermidis (biofilm-positive) and Escherichia coli (extended-spectrum beta-lactamase [ESBL]-producer) were inoculated to triclosan-coated and noncoated polyglactin 910 sutures to evaluate comparative adherence of bacterial isolates to the antibacterial coated and noncoated surgical sutures; to assess the impact of serum proteins (bovine serum albumin) on antibacterial activity of triclosan-coated suture; and to document the duration of antibacterial activity of the triclosan-coated material. Selected suture samples were prepared for scanning electron microscopy to demonstrate bacterial adherence. RESULTS: Substantial (p < 0.01) reductions in both Gram-positive and Gram-negative bacterial adherence were observed on triclosan-coated sutures compared with noncoated material. Pretreatment of surgical sutures with 20% BSA did not diminish antibacterial activity of the triclosan-coated braided device compared with noncoated suture (p < 0.01), and antibacterial activity was documented to persist for at least 96 hours compared with controls (p < 0.01). CONCLUSIONS: The in vitro model demonstrated a considerable reduction (p < 0.01) in Gram-positive and Gram-negative bacterial adherence to a triclosan-coated braided suture, which was associated with decreased microbial viability (p < 0.001). Because bacterial contamination of suture material within a surgical wound may increase the virulence of a surgical site infection, treating the suture with triclosan provides an effective strategy for reducing perioperative surgical morbidity.     

Toxicity of chlorhexidine irrigation in chronic postpneumonectomy empyema

Three patients with chronic Staphylococcus aureus empyema following pneumonectomy were treated with continuous chlorhexidine (0.02%) irrigation of the cavity. The empyema became sterile, but after a few days symptoms of cerebral intoxication appeared in all three patients. The symptoms resolved when the treatment was discontinued. Use of continuous chlorhexidine irrigation treatment of large wounds and cavities is therefore to be discouraged.