In vitro assessment of chlorhexidine gluconate-impregnated polyurethane foam antimicrobial dressing using zone of inhibition assays.

OBJECTIVE: To evaluate an antimicrobial dressing consisting of hydrophilic polyurethane foam with chlorhexidine gluconate for activity against several antibiotic-resistant clinical isolates as well as American Type Culture Collection reference strains using zone of inhibition assays. METHODS: Sterile foam samples with chlorhexidine gluconate and untreated controls were transferred onto inoculated agar plates. Plates were incubated at 35 degrees C to 37 degrees C for 24 hours and examined for zones of inhibition around the foam samples. RESULTS: Polyurethane foam with chlorhexidine gluconate showed antimicrobial activity in vitro against all of the challenge organisms including antibiotic-resistant clinical isolates. CONCLUSION: The data from this in vitro study support the hypothesis that polyurethane foam with chlorhexidine gluconate has an antimicrobial effect against antibiotic-resistant Staphylococcus and Enterococcus species, as well as Candida species.     

Changes to dose at surface and shifts of dose distributions at depth through dry and wet wound dressings for photon and electron beam radiotherapy

Wound dressings are used during patient radiotherapy treatments, particularly in cases of radiation induced lesions. Potentially, the presence of a dressing may increase the dose to the skin, further aggravating the skin reaction and decrease the dose at depth. The changes are dependent on linear accelerator beam type and beam quality and were determined for 4 and 10 MV photon energies and 6 and 15 MeV electron energies using a slab phantom and fixed separation parallel plate chambers. Since these dressings have been designed to be used on exuding wounds, measurements were taken under eight different wound dressings in both dry and wet state. Irradiations with photon energies increased the skin dose significantly (max. increase: 68.1 %; average increase: 48 %) with little or no change to dose at depth. Electron beam energies showed little or no change to doses at the surface, but the dose distribution was shifted towards the surface. The maximum decrease in dose at depth was 3.6 % for 6 and 15 MeV through all dressings except one and was therefore considered to be clinically insignificant. A change in dose at surface of 9.7 % and at R(50) of 25.9 %, equivalent to a shift of dose towards the surface of 7.5 mm, was measured for one dressing. This demonstrates that it is possible for a wet dressing to significantly alter electron beam dosimetry.     

A comparison of the antimicrobial activity of garlic, ginger, carrot, and turmeric pastes against Escherichia coli O157:H7 in laboratory buffer and ground beef

The antimicrobial effects of garlic, ginger, carrot and turmeric pastes against Escherichia coli O157:H7 in laboratory buffer and model food system were investigated. Turmeric paste, fresh carrot, ginger and garlic pastes from roots, and commercial ginger and garlic paste were heated alone or with buffered peptone water (BPW) or ground beef at 70 degrees C for 7 min. All samples were inoculated with a three strain cocktail of overnight cultures of E. coli O157: H7 and stored at 4 degrees C and 8 degrees C for 2 weeks. Each paste exhibited different antimicrobial effects alone and in ground beef or BPW at 4 degrees C and 8 degrees C for 2 weeks. Commercial ginger paste and fresh garlic paste showed the strongest antimicrobial activity with complete inactivation of E. coli O157:H7 in the paste at 3 days at 4 degrees C and 8 degrees C. Carrot and turmeric pastes did not show any antimicrobial activity both at 4 degrees C and 8 degrees C. Commercial garlic showed antimicrobial activity at both 4 degrees C and 8 degrees C (about 1 log CFU/g reduction) in the paste. However, fresh ginger paste showed antimicrobial activity only at 8 degrees C. Only commercial ginger paste had antimicrobial activity in BPW at 4 degrees C for 2 weeks. However, commercial ginger paste showed antimicrobial activity in ground beef at 3 days and after (about 1-2 log CFU/g) compared to control samples at 8 degrees C for 2 weeks. Fresh garlic paste showed antimicrobial activity only in BPW (1.3 log CFU/g) at 8 degrees C. These results indicate that the antimicrobial activity of these pastes is decreased in ground beef and laboratory buffer.     

Effects of heating, storage, and ultraviolet exposure on antimicrobial activity of garlic juice

This study was designed to investigate the effect of heating, storage, and ultraviolet exposure on antimicrobial activity of garlic juice and its bacteriocidal activity against common human pathogens. Antimicrobial activity of fresh garlic juice was tested against Escherichia coli, Staphylococcus aureus, Streptococcus hemolyticus B, S. hemolyticus A, Klebsiella sp., Shigella dysenteriae, and Candida albicans using the disc method. The dilution method was performed by addition of garlic juice to broth media to obtain 1-100% concentrations as vol/vol or wt/vol. Garlic juice was used after 24 hours of storage at 4 degrees C, heating to 100 degrees C for 5 minutes, 10 minutes, 30 minutes, and 60 minutes, heating to 80 degrees C for 60 minutes, and 4 hours of exposure to ultraviolet light. Re-culture of specimens taken from garlic-induced negative media was performed in fresh broth free of garlic juice. Results showed that all the isolates were sensitive to fresh garlic juice; the most sensitive was C. albicans, and the least sensitive was S. hemolyticus A. Heating to 100 degrees C for 30 and 60 minutes completely abolished the antimicrobial activity, while heating for 5 and 10 minutes, storage for 24 hours, and 4 hours of ultraviolet exposure decreased it. Garlic juice was bactericidal at concentrations of 5% and more. Thus garlic juice has marked antimicrobial activity that makes it a potential agent to be tested in clinical trials. The antimicrobial activity was compromised by storage and heating; therefore it is advisable to use fresh garlic and avoid boiling it for more than 5 minutes during cooking.     

Microbial growth and endotoxin production in the intravenous anesthetic propofol

OBJECTIVE: In this study, we measured microbial growth and endotoxin production in the intravenous anesthetic propofol using 10 different microbial strains; 6 isolated from outbreak cases and 4 from laboratory stock cultures. DESIGN: In each trial, endotoxin-free glass tubes containing 10 ml propofol were inoculated with 10(0)-10(3) CFU/ml of the test organism and incubated at 30 degrees C for 72 hours. SETTING: In May and June 1990, the Centers for Disease Control received reports of 5 outbreaks in 5 states of postsurgical patient infections and/or pyrogenic reactions. Epidemiologic and laboratory investigations implicated extrinsic contamination of an intravenous anesthetic, propofol, as the probable source of these outbreaks. RESULTS: After 24 hours, 9 of the 10 cultures increased in viable counts by 3 to 6 logs. At least 1 ng/ml of endotoxin was produced within 24 hours by Escherichia coli, Enterobacter cloacae, and Acinetobacter calcoaceticus subspecies anitratus. CONCLUSIONS: Propofol can support rapid microbial growth and endotoxin production. To avoid infectious complications, scrupulous aseptic technique should be used when preparing or administering this anesthetic.     

Nanocrystalline silver dressings as an efficient anti-MRSA barrier: a new solution to an increasing problem

The emergence of multi-drug-resistant strains of bacteria represents a particular challenge in the field of wound management. The aim of the current study was to investigate whether nanocrystalline silver dressings possess the physical properties to act as a barrier to the transmission of methicillin-resistant Staphylococcus aureus (MRSA) in the laboratory setting and in a clinical setting. Initially, MRSA suspension and colony culture experiments were performed showing that nanocrystalline silver dressings act as potent and sustained antimicrobial agents, efficiently inhibiting MRSA penetration. Subsequently, a double-centre clinical trial was initiated using nanocrystalline silver dressings as a cover for 10 MRSA colonized wounds in a total of seven patients. By delineating the MRSA load on the upper side of the dressing and the wound bed each time the dressing was changed (i.e. after 1, 24, 48 and 72 h), nanocrystalline silver dressings were found to provide a complete, or almost complete, barrier to the penetration/spread of MRSA in 95% of readings. In addition, 67% of all wound observations showed a decrease in the MRSA load with an eradication rate of 11%. We believe that nanocrystalline silver dressings may become an important part of local MRSA management, with cost benefits to both patients and the healthcare system.     

Evaluation of a multiplex PCR system for simultaneous detection of Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7 in foods and in food subjected to freezing

Conventional culture methods were compared to a multiplex polymerase chain reaction (PCR) assay for simultaneous detection of Salmonella spp., Listeria monocytogenes, and Escherichia coli O157:H7 from enrichment cultures of various types of artificially inoculated and naturally contaminated foods. The multiplex PCR assay was evaluated in 44 types of spiked food samples, including meat, produce, fish, and dairy products targeting genes specific for each pathogen for simultaneous detection. The sensitivity of the assay was 相似文献   

移动换药车换药前后细菌污染状况调查

目的调查移动换药车换药前后细菌污染状况。方法采用现况调查方法,分别于2016年3月23日—6月26日和2017年8月8日—9月13日对某院整形烧伤病房的一辆换药车进行采样,换药车使用前、后及消毒静置3h后分别于车把手、抽屉把手和车顶层采样,进行细菌培养,并计算单位面积细菌菌落数,比较不同采样时机菌落数差异。结果本研究共采样303份,其中换药前样本90份,换药后样本123份,消毒静置3h后样本90份。不同采样时机换药车顶层菌落数比较,差异有统计学意义(P=0.003);组间比较结果显示,换药后车顶层菌落数较换药前及消毒静置3h后均增加(均P0.05)。不同换药时机车把手、抽屉把手菌落数比较,差异均无统计学意义(均P0.05)。相同采样时间点换药车各部位间菌落数比较,差异均无统计学意义(均P0.05)。换药前换药车3个部位的样本合格率均为100.00%,换药后车把手、抽屉把手和车顶层样本合格率分别为100.00%、97.56%和97.56%,3个部位消毒静置3h后样本合格率也均为100.00%。结论移动换药车采用的物体表面消毒方法可达到我国医院消毒卫生标准对于II类环境物体表面的卫生标准,换药车消毒后在3h内移动使用基本安全。     

The antimicrobial effects of chopped garlic in ground beef and raw meatball (ciğ köfte)

This study was carried out to investigate the antimicrobial effects of chopped garlic in ground beef and raw meatball (?ig k?fte), which is a traditional food product eaten raw. Fresh minced ground beef and raw meatball batter prepared with traditional methods were separated into groups. Chopped and crushed garlic was added to each batch in order to reach various concentrations from 0% to 10%. The ground beef samples were stored at refrigerator and ambient temperatures. The raw meatball samples were only stored at room temperature. All samples were analyzed in order to determine the microbial counts at the 2(nd), 6(th), 12(th), and 24(th) hours of storage. Garlic addition decreased the microbial growth in some ground beef samples kept either at room temperature or in the refrigerator. However, microbial growth increased in some ground beef samples kept in similar conditions. The difference was found in samples kept in the refrigerator for 24 hours in terms of total aerobic mesophilic bacteria and coliform bacteria when garlic used at 10%. The effects of garlic on the microbial growth of both coliforms and Staphylococcus/Micrococcus in the samples kept at room temperature were increased. The yeast and mold counts in ground beef samples kept in any condition were not affected by garlic addition. However, the addition of garlic to the raw meatball mix decreased the microbial count, in terms of total aerobic mesophilic bacteria and yeast and mold counts, when the garlic was added at 5% or 10% (P < .05). The addition of 10% garlic to raw meatball caused a permanent decrease in yeast and mold count, unlike in ground beef. The results of this study indicate that the chopped garlic has a slowing-down effect on microbiological growth in ground meat depending on the garlic concentration, but this effect was not at an expected level even at the highest concentration, because potential antimicrobial agents in chopped garlic were probably insufficiently extracted.     

Antimicrobial properties of antiseptic-impregnated biological dressings

Three antiseptics--chlorhexidine acetate, silver nitrate and povidone-iodine--were incorporated into biological dressings (human skin and amnio-chorion) and evaluated in vitro against disparate micro-organisms. Results indicated that antimicrobial levels of chlorhexidine and silver were released from the dressings over a clinically relevant time period, whereas povidone-iodine was ineffective. Chlorhexidine dressings demonstrated broad-spectrum activity, whereas silver dressings were most effective against Pseudomonas aeruginosa.     

应用模块化理论研制卫生列车救护中的清创换药箱

目的：研制适用于卫生列车救护中的清创换药箱,也可用于平战时突发事件中伤员的救护。方法：应用三级模块化理论．结合卫生列车后送的主要任务,把清创换药箱设计成4个功能区：消毒清洗液区、清创换药共用区、污染伤口换药区和感染伤口换药区。各功能区相对独立又紧密联系,是模块化中的三级模块（单元）,能完成5次清创和50次换药。结果：该清创换药箱备物齐全。功能完整,实用便捷。结论：该清创换药箱克服了一般换药箱物品凌乱、功能单一的缺点．具有模块化设计、功能齐全、可扩展性等创新点,可满足卫生列车救护中的清创换药需求。     

藻酸盐湿性敷料在腹部手术后切口愈合不良中的应用效果

目的观察藻酸盐湿性敷料在腹部手术后切口愈合不良中的应用效果。方法选取2018-07至2019-06广州市第一人民医院南沙医院进行腹部手术后切口愈合不良患者70例为研究对象,按切口敷料不同分为对照组(n=35)和观察组(n=35)。对照组,接受传统敷料处理;观察组,接受藻酸盐湿性敷料处理。比较两组伤口愈合时间、伤口感染控制时间、首次更换敷料时疼痛评分及再发感染率等。结果观察组切口愈合时间、切口感染控制时间均明显短于对照组,差异有统计学意义(P<0.05)。观察组首次更换敷料时伤口疼痛评分明显低于对照组,差异有统计学意义(P<0.05);两组再发感染率比较,差异无统计学意义(P>0.05)。结论藻酸盐敷料在腹部手术后切口愈合不良中应用效果较好,能缩短愈合时间,加快感染控制速度。     

A comparative study of 'Op-site' and 'Nobecutan gauze' dressings for central venous line care

A comparative study of 'Op-site' and 'Nobecutan-gauze' dressings for central venous lines was performed. Seventy-seven long antebrachial and 68 infraclavicular subclavian catheters were studied. A statistically significant reduction in the incidence of positive cultures from the catheter tip and from the skin puncture site was found with the 'Nobecutan-gauze' dressing. No difference in the incidence of catheter-related septicaemia was found. The theoretical advantage of being able to observe signs of inflammation when 'Op-site' was used did not reduce the incidence of local infection at the skin puncture site. In conclusion we found that a 'Nobecutan-gauze' dressing was a satisfactory alternative to an 'Op-site' dressing.     

Comparison of different culture media and storage temperatures for the long-term preservation of Streptococcus pneumoniae in the tropics

OBJECTIVE: The preservation of Streptococcus pneumoniae by standard freezing methods for subsequent tests--such as serotyping and antibiotic susceptibility--is not possible or is difficult in many developing countries because of the high cost of equipment, inadequate equipment maintenance, and irregular power supply. We evaluated alternative low-cost methods, by comparing different culture media and storage temperatures. METHODS: Clinical isolates of five capsular types (1, 5, 7, 19, and 23) of S. pneumoniae were preserved in rabbit blood, sheep blood, skimmed milk, or glycerol-chocolate broth, and stored at -20 degrees C or -70 degrees C. The cultures were also preserved by lyophilization or sand desiccation, followed by storage at room temperature and 4 degrees C. The viability of the preserved cultures was determined by making serial colony counts on day 0 and after 1 week, 4 weeks, 4 months and 16 months. The viability of cultures preserved by sand desiccation and storage at 4 degrees C was also determined every 6 months for up to 68 months. FINDINGS: Irrespective of the media used, cultures maintained at -20 degrees C became nonviable by the fourth month, while those maintained at -70 degrees C were still viable at 16 months. Cultures preserved by lyophilization or sand desiccation lost their viability by the fourth month when maintained at local room temperature (30-42 degrees C), but remained viable when stored at 4 degrees C for up to 68 months. CONCLUSIONS: Our results confirm that freezing at -70 degrees C, or lyophilization and storage at 4 degrees C are the ideal methods for the preservation of S. pneumoniae. In laboratories where lyophilization is not feasible, sand desiccation and storage at 4 degrees C offers an alternative low-cost method for the long-term preservation of S. pneumoniae.     

Growth and survival of selected pathogens in margarine-style table spreads

Although margarine-style table spreads can have a pH above 4.6 and a water activity greater than 0.85, there is some question if such products can support the growth of pathogenic bacteria. The objective of this study was to evaluate the growth and survival of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella typhi in 60-percent- and 70-percent-vegetable-oil, margarine-style, water-in-oil-emulsion table spreads stored at different temperatures. Samples of 25 grams of each table spread were inoculated with 1 x 10(3) cells of each bacterial mixture. The samples were stored at 5 degrees C, 7 degrees C, and 21 degrees C, and the microbial population in colony-forming units per gram (CFU/gram) was enumerated over time. In almost all storage conditions, bacterial levels were shown to decrease over time. Inactivation was observed in (listed from fastest to slowest, respectively) S. aureus, L. monocytogenes, E. coli O157:H7, and S. typhi. Growth was observed only for S. typhi in table spreads stored at 21 degrees C, but the rate of growth was extremely slow. Based on these findings, the table spreads evaluated in this study are not potentially hazardous foods, and cold temperature storage is not necessary from a food safety perspective.     

蜂蜜用于皮肤软组织擦挫创面感染的临床研究

目的探讨自制蜂蜜敷料治疗皮肤软组织擦挫创面感染的临床效果。方法复习相关文献,分析蜂蜜的理化特性及药效机制;将入选的125例患者按随机数字表法分为试验组和对照组;试验组65例,采用自制的蜂蜜敷料换药,每日1次,感染控制后,2~3 d换药1次,直至愈合;对照组60例,采用传统方法凡士林油纱换药;观察两组疼痛程度、创面感染控制及愈合时间。结果试验组与对照组疼痛计分分别为(1.97±0.61)、(5.63±0.92)分,差异有统计学意义(P<0.01),试验组换药疼痛轻;试验组创面感染控制及愈合时间明显少于对照组,差异有统计学意义(P<0.01)。结论蜂蜜敷料能及时有效的控制感染,促进创面修复。     

Maintenance of infectivity of Trypanosoma congolense in vitro with explants of infected skin at 37 degrees C

Glossina morsitans infected with two stocks of Trypanosoma congolense were fed on rabbits and calves to produce local skin reactions containing trypanosomes. Areas of infected skin were removed from the animals and used to prepare dermal explant cultures in Eagle's MEM and RPMI 1640 culture medium, supplemented with foetal bovine serum and containing penicillin and streptomycin. Cultures were incubated at 37 °C and media were changed at 24 to 48 hour intervals to maintain pH 7·0 to 7·2. There was evidence of trypanosome multiplication in explant cultures set up in both media; one trypanosome stock was maintained equally well in both Eagle's MEM and RPMI 1640, but the other stock survived better in Eagle's MEM. Explant cultures prepared from calf tissues generally yielded more trypanosomes at 24 hours than those prepared from rabbit tissues. The numbers of parasites present near the explants at 24 hours were maintained for up to 14 to 15 days before a decline in parasite concentration occurred. The organisms retained typical blood stream trypomastigote morphology and were infective for mice for periods up to 21 days. The trypanosomes growing in primary explant cultures could not be subpassaged in culture media alone or on to monolayers of fibroblast-like cells of bovine, murine or buffalo origin. Attempts to establish primary cultures by placing infected skin explants directly on to similar monolayers were also unsuccessful.     

Antimicrobial effect of chitooligosaccharides produced by chitosanase from Pseudomonas CUY8

The aim of this study was to investigate the antimicrobial effect of chitooligosaccharides prepared by chitosanase from Pseudomonas CUY8. Antimicrobial activities of different degrees of deacetylation (DD) and polymerization (DP) of chitooligosaccharides against various species of bacteria and fungi were measured. The antimicrobial effects of chitooligosaccharides compared with chitosan and chitosanase were evaluated. Inhibitory diameter of chitooligosaccharides at the concentration of 0.1% with DP 4 was 19 +/- 0.20mm, and inhibitory activity with DD 90% was 79+/- 2.1%, which were higher than other DP and DD, respectively. The results showed that antimicrobial activities of chitooligosaccharides increased with increase of DD, but decreased with increase of DP. Chitooligosaccharides, chitosan and chitosanase all showed significantly stronger antimicrobial activities against bacteria than fungi (p<0.001). Antimicrobial activities of chitooligosaccharides were significantly higher than that of chitosan (p<0.05), but insignificantly lower than that of chitosanase (p>0.05).     

Determination of antimicrobial activity of sorrel (Hibiscus sabdariffa) on Escherichia coli O157:H7 isolated from food, veterinary, and clinical samples

The use of medicinal plants as natural antimicrobial agents is gaining popularity. Sorrel (Hibiscus sabdariffa) is widely used for the treatment of diseases. The objective of this study was to investigate the antimicrobial activity of sorrel on Escherichia coli O157:H7 isolates from food, veterinary, and clinical samples. Phenolics of the calyces were extracted from 10 g of ground, freeze-dried samples using 100 mL of 80% aqueous methanol. Concentrations of 10%, 5%, and 2.5% methanol extract of sorrel were investigated for its antimicrobial activity. Inhibition zones were indicated by a lack of microbial growth due to inhibitory concentrations of sorrel diffused into semisolid culture medium beneath the sorrel-impregnated disk. The results of this experiment showed that the most potent sorrel concentration was 10%, then 5%, and finally 2.5%. The overall mean zone of inhibition for the sorrel extract was 12.66 mm for 10%, 10.75 mm for 5%, and 8.9 mm for 2.5%. The highest inhibition zones (11.16 mm) were observed in veterinary samples, and the lowest (10.57 mm) in the food samples. There were significant (P<.05) differences among mean zones of inhibition found in the food, veterinary, and clinical sources. Based on the source of samples and concentration of sorrel extract, the lowest mean inhibition was 7.00±0.04 mm from clinical samples, and the highest was 15.37±0.61 mm from a food source. These findings indicated that sorrel was effective at all levels in inhibiting E. coli O157:H7; thus it possesses antimicrobial activity and hold great promise as an antimicrobial agent.     

Cost-benefit analysis of chlorhexidine gluconate dressing in the prevention of catheter-related bloodstream infections.

OBJECTIVES: To compare the costs with the benefits of using chlorhexidine gluconate dressings on central venous catheters and to determine the effectiveness of these dressings in reducing local infections and catheter-related bloodstream infections (CRBSIs), costs, and mortality. DESIGN: Cost-benefit analysis using randomized, controlled trial data on chlorhexidine dressing prevention of local infection and CRBSI, data on cost of chlorhexidine dressing versus standard treatment, data on averted cost of treating local infection and CRBSI, and data on mortality attributable to CRBSI. Decision analysis evaluated averted CRBSI treatment cost per patient resulting from chlorhexidine dressing use. Sensitivity analyses demonstrated net benefit of chlorhexidine dressing, varying baseline rate of CRBSI, incremental cost of treating CRBSI, and number of catheters, and evaluated mortality preventable through chlorhexidine dressing use, varying baseline rate of CRBSI, number of catheters, and mortality attributable to CRBSI. PATIENTS AND SETTING: Patients of all Philadelphia area hospitals and one Philadelphia academic medical center. RESULTS: Estimated potential annual U.S. net benefits from chlorhexidine dressing use ranged from $275 million to approximately $1.97 billion. Cost-benefit findings persisted in sensitivity analyses varying baseline rate of CRBSI, incremental cost of treating CRBSI, and overall number of catheters used. Preventable mortality analyses showed potential decreases of between 329 and 3,906 U.S. deaths annually as a result of nationwide use of chlorhexidine dressing. CONCLUSIONS: Chlorhexidine dressings would reduce costs, local infections and CRBSIs, and deaths. Use of chlorhexidine dressings should be considered to prevent infections among patients with catheters.