012Molecular Mechanisms of Thrombin‐Induced Interleukin‐8 Expression in Human Macrophages

The onset of infection can lead rapidly to sepsis, septic shock, and eventually death. Considering the high costs of hospitalization and the added trauma and discomfort to the patient, improved methods for infection control are needed. Ozone offers a specific solution to the problem of effective management of microbial wound contamination. Despite the advantages, several technical barriers have prevented ozone‐based disinfection treatments from becoming more widely investigated. Negative press from years of unsubstantiated medical successes has made the medical community wary of even legitimate ozone technologies. Because there has been no research into using ozone in infection prevention, much of the hardware has not been developed to the stage where the technology can be used in clinical trials. Lynntech Inc., over the past 5 years, has been working to develop a pre‐clinical ozone‐based wound management system. This new hardware uses an electrochemical ozone generator that can deliver a predetermined quantity of ozone gas to a specific wound site. Electrochemically generated ozone has been shown to be effective against a range of gram negative and gram positive bacteria and our studies with various mimetic wound systems have shown that with controlled delivery, ozone can be utilized as either a disinfectant or as a biostat. The device is well suited for hospital use as it operates of low voltage power supplies and unlike other ozone generation technologies will not interfere with other electronic equipment while it is in operation. This paper outlines both the advantages and limitations of using an ozone based system as a wound management tool and looks to the future research that needs to be performed to substantiated the initial research findings.     

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.     

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.     

008Cross – Talk between Fibroblasts and Keratinocytes in 3‐d Fibrin Clots. In Vitro Studies

Rimon Therapeutics develops synthetic therapeutic polymers (Theramers™) that combine bioactivity with a broad range of desirable mechanical and physical properties. The MI Theramer™ is a polymer that modulates the activity of matrix metalloproteinases (MMPs).. Excessive proteolytic cleavage of extracellular matrix and growth factors resulting from elevated levels of MMPs is believed to contribute to the impaired wound healing associated with chronic, non‐healing wounds. MI Theramer™ beads suspended in ThermaGel™(a thermoreversible gel) make up MI‐Gel™ Dressing. The dressing may be applied as a liquid that is poured into a wound, where it will gel on contact. The dressing can be reliquified and removed easily without re‐injuring the wound by cooling it.
In vitro inhibition of collagenase type IV (equivalent to MMP‐2) from clostridium histolyticum (Molecular Probes) was measured. A dose‐dependent inhibition of MMP‐2 activity was measured for MI Theramer™ beads alone and suspended in ThermaGel™ indicating that MMP‐2 is able to diffuse into the gel and bind to the beads suspended therein. In vivo efficacy was demonstrated by observing the degradation of glutaraldehyde cross‐linked gelatin tubes using a mouse subcutaneous pouch model. Gelatin zymography on extracts collected from the gelatin tubes co‐implanted with MI Theramer™ beads also showed reduced MMP‐2 and MMP‐9 activity in comparison to controls.
The insoluble MI Theramer™ beads were able to modulate MMP activity both in vitro and in vivo . The beads retained their inhibitory activity when they were suspended in a novel thermoreversible gel (ThermaGel™). The combined MI‐Gel™ Dressing may have promise as a novel chronic wound healing product.     

050The Angiogenesis Inhibitor Endostatin Impairs Wound Healing at Tumor‐inhibiting Doses

Effective blockade of the pluripotent cytokine TGF‐beta as a means of cutaneous scar reduction is a strategy with great potential. This desired effect may be achieved through the overexpression of mutant TGF beta receptors within the wound milieu. Our goal was to examine the effects of dominant negative mutant TGF‐beta receptor II (dnTGFRII) protein expression in a well‐established rabbit ear model of hypertrophic scarring. Serial injections of a retroviral construct encoding a truncated TGFβRII and the marker green fusion protein (pMSCV‐rIIdn‐GFP) were performed in 7mm punch wounds at day 10 and day 14 (two‐day injection group) or day 8, 10, 12 (three‐day injection group) post wounding. Delivery of a null vector (pMSCV‐GFP) at the same time points served as a negative control. Histomorphometric analysis of wounds harvested at day 28 revealed a statistically significant reduction (33%) in the scar elevation index in 2‐day treated and a more modest reduction in SEI (17.5%) in the 3‐day treated arm compared to null‐treated controls. Confocal microscopy confirmed stable transfection of the construct in both peri‐wound tissue as well as rabbit dermal fibroblasts transfected in vitro. Optimization of this novel application in retroviral gene therapy could lead to effective anti‐scarring strategies.     

An evaluation of the bacteriostatic effect of platelet‐rich plasma

Chronic wounds are a considerable health burden with high morbidity and poor rates of healing. Colonisation of chronic wounds by bacteria can be a significant factor in their poor healing rate. These bacteria can develop antibiotic resistance over time and can lead to wound infections, systemic illness, and occasionally amputation. When a large number of micro‐organisms colonise wounds, they can lead to biofilm formation, which are self‐perpetuating colonies of bacteria closed within an extracellular matrix, which are poorly penetrated by antibiotics. Platelet‐rich plasma (PRP) is an autologous blood product rich in growth factors and cytokines that are involved in an inflammatory response. PRP can be injected or applied to a wound as a topical gel, and there is some interest regarding its antimicrobial properties and whether this can improve wound healing. This study aimed to evaluate the in vitro bacteriostatic effect of PRP. PRP was collected from healthy volunteers and processed into two preparations: activated PRP—activated with calcium chloride and ethanol; inactivated PRP. The activity of each preparation against Staphylococcus aureus and Staphylococcus epidermis was evaluated against a control by three experiments: bacterial kill assay to assess planktonic bacterial growth; plate colony assay to assess bacterial colony growth; and colony biofilm assay to assess biofilm growth. Compared with control, both preparations of PRP significantly inhibited growth of planktonic S aureus and S epidermis. Activated PRP reduced planktonic bacterial concentration more than inactivated PRP in both bacteria. Both PRP preparations significantly reduced bacterial colony counts for both bacteria when compared with control; however, there was no difference between the two. There was no difference found between biofilm growth in either PRP against control or against the other preparation. This study demonstrates that PRP does have an inhibitory effect on the growth of common wound pathogens. Activation may be an important factor in increasing the antimicrobial effect of PRP. However, we did not find evidence of an effect against more complex bacterial colonies.     

Quantitative bacteriology in wound care.

Quantitative bacteriology in the management of wound sepsis provides an objective way to monitor the success or failure of wound care. The clinical appearance of a wound requiring skin grafting may be misleading. Grafting wounds that appeared clinically ready was unsuccessful when analysis showed bacteriological counts of 10(5) or greater organisms per gram of tissue. A rapid and simple method for quantitative tissue culture is described. Three cases are described illustrating the value of the results of the method.     

Antibiotic prophylaxis diminishes bacterial translocation but not mortality in experimental burn wound sepsis

Pseudomonas (PSA) burn wound sepsis results in prolonged bacterial translocation (BT) of enteric organisms such as E. coli to the mesenteric lymph nodes (MLN) and organs in rats. Intestinal decontamination with oral antibiotics may improve mortality after burn injury, perhaps due to decreased BT. To determine the effect of oral antibiotic prophylaxis effective against E. coli but not PSA on BT and subsequent mortality in a model of PSA burn wound sepsis, rats were given a 30% scald burn and wound inoculation with 10(8) PSA followed by randomization to either ampicillin (50 mg/kg/d) or saline gavage. Cultures of MLN, organs, blood, and cecal contents were obtained on days 1, 4, and 7 after injury, with additional animals observed for 14-day mortality. Although oral antibiotic prophylaxis resulted in increased cecal colony counts, the incidence of BT was unchanged. The number of organisms present in both the MLN and organs, however, was significantly reduced with prophylaxis, indicating cecal overgrowth by non-translocating bacteria. Reduction of the number of translocating organisms did not result in improved mean survival time after injury, suggesting that mortality from PSA burn wound sepsis occurs independently of bacterial translocation.     

Hepatitis C Virus Infection is Highly Correlated with Hepatocellular Apoptosis and Transforming Growth Factor‐β1 MRNA Expression in Patients with Chronic Hepatitis C

Introduction:  The cellular phases (granulation, reepithelialization, and dermal remodelling) of the healing process involve many cell types. Fibroblasts and myofibroblasts are the key cells in granulation tissue formation and wound contraction.
Objective:  To compare the effects on cultured human fibroblasts of a new nonadhesive lipidocolloid wound dressing, Urgotul^®, with five other wound dressings including impregnated gauzes and some other modern wound dressings.
Method:  Cultures in monolayer were used to study the morphology and growth of fibroblasts. The Bell model of cultured dermis equivalents was used to investigate myofibroblast differentiation. These cultures were labelled α‐SM actin and F‐actin.
Results:  Two of the tested dressings induced cytotoxic effects on the fibroblasts. They were found to inhibit cell growth (greater than 60%) and to disturb cell shape and cytoskeletal differentiation. Urgotul^® and the remaining three dressings showed no effect on proliferation. However some of them modified fibroblast morphology and affected F‐actin distribution.
Conclusion:  Depending on their nature and components, wound dressings may respect or affect in vitro fibroblast behaviour (proliferation, morphology, and α‐SM actin and F‐actin distribution). The observed in vitro findings require further investigations.     

Use of acridine orange to evaluate chromatin integrity of human spermatozoa in different groups of infertile men

To study the sperm chromatin compactness various methods, such as acidic aniline blue or acridine orange staining, have been applied. Due to its metachromatic properties, acridine orange dye fluoresces green with double- and red with single-stranded DNA. Samples (n = 181) were evaluated and grouped as follows: group I, normal recently fertile; group II, male having female partner with repeated early pregnancy loss; group III, male with varicocele; and group IV in-vitro fertilization and intrauterine insemination failures. Routine semen analyses were carried out in all the cases. Amorphous particulate matter as observed under phase contrast microscope was graded on the scale of nil to +4. Fixed smears were stained with an aqueous solution of acridine orange and viewed under a fluorescence microscope. Two hundred cells were counted and the percentage of fluorescence calculated. Groups II, III and IV exhibited significantly low green fluorescence compared with the control group. The study also indicates that increased amorphous particulate matter (indicating infection) might be one of the contributing factors to lower acridine orange stainability. Thus acridine orange staining can be used to evaluate the integrity of the nucleus, disorders of which can cause unexplained infertility or lower fertilization potential that may go undetected by routine analysis.     

烧伤创面多重耐药鲍氏不动杆菌同源性和碳青霉烯酶基因型及整合子研究

目的 明确甘肃省人民医院烧伤病房多重耐药鲍氏不动杆菌的耐药性、同源性及与整合子的关系. 方法 31株多重耐药鲍氏不动杆菌分离自该院烧伤住院患者创面分泌物标本.采用琼脂稀释法测定鲍氏不动杆菌对11种抗菌药物的最低抑菌浓度(MIC);脉冲场凝胶电泳(PFGE)分析菌株的同源性:PCR扩增I、Ⅱ、Ⅲ类整合酶及整合酶阳性菌株的整合子基因盒,进行序列分析;分析亚胺培南耐药菌株的碳青霉烯酶基因型. 结果 鲍氏不动杆菌对亚胺培南、美罗培南、哌拉西林/他唑巴坦和头孢哌酮/舒巴坦的耐药率分别为45.2%、48.4%、48.4%、41.0%,对头孢他啶、头孢吡肟、环丙沙星、阿米卡星、庆大霉素、氨曲南和哌拉西林的耐药率均在80.0%以上.所有菌株PFGE分型共分为A、B、C 3型,A克隆18株、B克隆7株、C克隆6株.20株细菌整合子扩增阳性,携带有aadA1、aadA5、aacA4、aac3、aacC1、aac(6')-Ib、catB8、drfA17和drf8基因,介导对氨基糖苷类抗生素、氯霉素、甲氧苄啶的耐药.14株亚胺培南耐药的菌株均产OXA-23型碳青霉烯酶. 结论 多重耐药鲍氏不动杆菌在该院烧伤病房播散,以A克隆为主;鲍氏不动杆菌整合子主要介导对氨基糖苷类抗生素及氯霉素的耐药性,碳青霉烯类抗生素耐药鲍氏不动杆菌均产OXA-23型碳青霉烯酶.     

Selecting patients requiring antibiotics in biliary surgery by immediate gram stains of bile at operation.

The value of selecting patients for antibiotic cover during biliary surgery by the use of immediate gram stains of bile was determined in a nonrandomized prospective study which compared two groups of patients. Group A consisted of 119 consecutive patients in whom antibiotics were administered during operation according to the results of immediate gram stains on bile. Group B included 101 patients, none of whom received antibiotics. In Group A gentamicin was given for gram-negative bacteria, ampicillin for gram-positive organisms, and no antibiotics were given if no bacteria were seen on the gram stain. In Group A the incidence of wound sepsis was 7 percent, compared with 22 percent in Group B (p less than 0.005). Septicemia occured in 2 percent of Group A, compared with 8 percent in Group B. It is concluded that immediate gram stains of bile will provide a means of selecting patients requiring antibiotic cover during biliary surgery; furthermore, this procedure is a practical way of reducing postoperative sepsis while avoiding unnecessary antibiotic administration.     

051Superoxide Regulates α‐SMA via p‐38 MAPK

This study was to investigate the effect of cyclic mechanical stretching on superoxide and nitric oxide production in human patellar tendon fibroblasts (HPTFs) and to establish the role of superoxide and p38 MAPK in stretching‐induced α‐smooth muscle actin (α‐SMA) expression. When HPTFs were grown in deformable silicone dishes and subjected to 8% cyclic, uniaxial stretching, it was found that HPTFs markedly increased the production of superoxide and nitrite but not nitric oxide. And, cyclic stretching of HPTFs increased phosphorylation of p38 MAPK with increasing stretching magnitude. In addition, stretching duration also influenced the expression of phosphorylated p38 MAPK, where the dependence followed a pattern of cellular response in p38 MAPK activation consistent with previous studies using human mesangial cells and rat 3Y1 fibroblasts. For short stretching durations (∼15 min), the expression of phosphorylated p38 MAPK increased rapidly but decreased for longer stretching durations. Furthermore, in HPTFs treated with superoxide dismutase (SOD), which converts superoxide anions to hydrogen peroxide and an oxygen molecule, levels of stretching‐induced p38 MAPK phosphorylation and α‐SMA expression decreased compared to stretched fibroblasts not treated with SOD. Similarly, cells treated with SB202190, which specifically inhibits p38 MAPK activation, also decreased α‐SMA expression levels. Therefore, these results suggest that superoxide regulates stretching‐induced α‐SMA expression via p38 MAPK activation in HPTFs subjected to cyclic stretching conditions.     

Multidrug‐resistant Gram‐negative bacterial infections in solid organ transplant recipients—Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of infections due to multidrug‐resistant (MDR) Gram‐negative bacilli in the pre‐ and post‐transplant period. MDR Gram‐negative bacilli, including carbapenem‐resistant Enterobacteriaceae, MDR Pseudomonas aeruginosa, and carbapenem‐resistant Acinetobacter baumannii, remain a threat to successful organ transplantation. Clinicians now have access to at least five novel agents with activity against some of these organisms, with others in the advanced stages of clinical development. No agent, however, provides universal and predictable activity against any of these pathogens, and very little is available to treat infections with MDR nonfermenting Gram‐negative bacilli including A baumannii. Despite advances, empiric antibiotics should be tailored to local microbiology and targeted regimens should be tailored to susceptibilities. Source control remains an important part of the therapeutic armamentarium. Morbidity and mortality associated with infections due to MDR Gram‐negative organisms remain unacceptably high. Heightened infection control and antimicrobial stewardship initiatives are needed to prevent these infections, curtail their transmission, and limit the evolution of MDR Gram‐negative pathogens, especially in the setting of organ transplantation.     

烧伤病房728株感染病原菌的分布特点及耐药性分析

目的了解笔者单位近5年烧伤感染病原菌的分布特点及耐药情况。方法收集2001-2006年笔者单位306例烧伤患者创面分泌物等标本中分离的病原菌，对其菌种分布特点及耐药性进行分析。结果革兰阳性菌378株，其中金黄色葡萄球菌的菌株数居首位，尤以甲氧西林耐药金黄色葡萄球菌居多，表皮葡萄球菌和粪肠球菌的菌株数分别位居第2、3位。革兰阴性杆菌338株，其中鲍氏不动杆菌的菌株数居首位，阴沟肠杆菌和铜绿假单胞菌的菌株数分别位居第2、3位。检出真菌12株。结论笔者单位病原菌的分布情况，可能与甲氧西林耐药葡萄球菌呈多重耐药性以及鲍氏不动杆菌产生各种类型的β内酰胺酶有关。     

Systemic antibiotic treatment in burned patients

Systemic antibiotics are a valuable therapeutic modality in the burned patient when properly used. Injudicious use, however, may not only fail to be beneficial to the patient but also may produce harmful effects--either through direct toxicity or by contributing to the emergence of resistant strains of micro-organisms. General guidelines and principles for systemic antibiotic use include the following: The burned patient, despite all efforts, will be exposed to microorganisms. No single agent or combination of agents can destroy all the organisms to which the burned patient is exposed. Treatment involves first identifying the organism responsible for clinical sepsis, then choosing appropriate agents. Combinations of antibiotics are not always synergistic or even additive in effect. Multiagent therapy may have the untoward effect of predisposing to superinfection by yeast, fungi, or resistant organisms. Antibiotics should be used for a long enough period to produce an effect, but not long enough to allow for emergence of opportunistic or resistant organisms. Dosages must be adjusted based on serum concentrations when serum assays are available. In general prophylactic systemic antibiotics are indicated in only a few clinical situations including the immediate preoperative and postoperative periods associated with excision and autografting, and possibly in the early phases of burns in children. The penetration of systemic antibiotics into burn eschar remains an area not fully studied; hence, they cannot be the only therapeutic modality used to treat burn wound infection. Systemic dosages of antibiotics in burns will require alteration depending on the clinical status of the patient. The choice of agent requires a thorough knowledge of side effects, toxicity, and potential benefit. Above all, active surveillance and monitoring of the burned patient and the environment in which he or she is being treated is mandatory for effective treatment. The increasing number of new antimicrobial agents has presented a new dilemma to the practicing clinician because many of these agents have not been evaluated thoroughly in the burned population. With further studies, the armamentarium of the burn treatment team will inevitably increase. It is in this manner only that so many of the unanswered questions will be solved, and that infection will start to decline as the major cause of death in the burned population.     

阿伦膦酸钠对破骨细胞凋亡的影响

目的：本研究采用吖啶橙染色方法观察阿伦膦酸钠对破骨细胞凋亡的影响。方法：将阿伦膦酸钠加入培养液配成终浓度为10^-10mol/L、10^-8mol/L、10^-6mol/L。阿伦膦酸钠作用6h，吖啶橙染色，倒置荧光显微镜下观察凋亡破骨细胞所占的比例。结果：吖啶橙染色能展示凋亡破骨细胞的形成。阿伦膦酸钠促进破骨细胞凋亡，随阿伦膦酸钠浓度的增加，破骨细胞凋亡的比例也增加。结论：吖啶橙染色是检测破骨细胞凋亡简便实用的方法，阿伦膦酸钠通过促进凋亡降低破骨细胞数量，降低骨吸收。     

下呼吸道感染的病原菌分布与耐药性分析

目的：分析临床下呼吸道感染病原菌构成及耐药情况,以指导临床医师合理应用抗菌药物.方法：分析2008年1月-2012年12月解放军总医院第一附属医院从痰（19 365份）、支气管灌洗液（4 203份）以及支气管肺泡灌洗液（302份）标本分离细菌的鉴定及药敏试验结果.结果：共分离出非重复病原菌10 635株,其中革兰阴性杆菌5 244株（49.3%）,革兰阳性球菌2 495株（23.5%）,真菌2 896株（27.2%）.未发现葡萄球菌属对万古霉素、替考拉宁和利奈唑胺的耐药菌株,发现3株大肠埃希菌和32株肺炎克雷伯菌对碳青霉烯类耐药菌株（CRE）,多重耐药铜绿假单胞菌（MDRPA）和鲍曼不动杆菌（MDRAB）分别占14.2%和46.3%.真菌以白色念珠菌为主,对抗真菌药较敏感.结论：下呼吸道感染分离的病原菌中鲍曼不动杆菌、铜绿假单胞菌和金黄色葡萄球菌是主要病原菌,同时耐碳青霉烯类的肠杆菌科细菌（CRE）以及耐万古霉素的肠球菌属（VRE）也是临床抗感染治疗的难点.     

The effects of topical oral clindamycin antibiotic rinses on the bacterial content of saliva on healthy human subjects.

The use of systemic antibiotics for major head and neck surgical procedures involving the upper aerodigestive tract is now accepted as an important part of perioperative patient care. Despite knowledge of the high counts of bacteria present in saliva, no preoperative regimen for preparing the mouth has been standardized. Surgical wounds come in contact with saliva during the course of many head and neck procedures. While wound infection rates have been decreased with the use of prophylactic systemic antibiotics, serious morbidity still exists from postoperative wound infections. Reducing the bacterial counts in saliva preoperatively may further decrease wound infection rates. A prospective randomized pilot study of twenty healthy human subjects compared the effects of an oral rinse with clindamycin vs. a placebo rinse of normal saline. There was a statistically significant reduction in both aerobic and anaerobic colony counts in the clindamycin group at 4 hours after treatment. For the group that rinsed with placebo, there was an actual increase in counts 4 hours after treatment. It is concluded that oral rinses with clindamycin can reduce the bacterial content of saliva for a sufficient length of time to be effective as a preoperative prophylactic measure for head and neck surgery involving the upper aerodigestive tract. Future studies are planned to evaluate other potentially effective agents. A logical continuation is a clinical study of preoperative and postoperative rinses.