Sterile Towel Research Articles

Implant contamination during spine surgery

Background contextPostoperative spine infections have been reported to occur in 1% to 15% of patients and subsequently lead to significant morbidity and cost, with an elevated risk for instrumented cases. Every effort should be made to minimize the risk of intraoperative wound contamination. Consequently, certain practices are followed in the operating room to prevent contamination, many of which are not evidence based. Conversely, certain objects believed to be sterile are frequently overlooked as potential sources of contamination. PurposeTo assess to what degree contamination of spinal implants occurs during spine surgery and evaluate whether coverage of implants alters the rate of contamination. Study designProspective study. Study sampleThis study included 105 consecutive noninfection surgical cases performed by a single spine surgeon that required the use of instrumentation. Outcome measureSpinal implant contamination. MethodsCases were randomized to have all implant trays either remain uncovered (n=54) or covered (n=51) with sterile surgical towels on opening until implants were required for the case. After the last implant was placed, a sterile culture swab was used to obtain a sample from all open implants that had been present at the start of the case. The paper outer wraps of the implant trays were sampled in each case as a positive control, and an additional 105 swabs were capped immediately after they were opened to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates. Of note, only departmental funding was used and no applicable financial relationships exist with any author. ResultsNo growth was observed on any of the 105 negative controls, whereas 99.1% of positive controls demonstrated obvious contamination. Cultures from implant samples demonstrated a 9.5% overall rate of contamination with 2.0% (n=1) of covered implants versus 16.7% (n=9) of uncovered implants demonstrating contamination. Length of time implant trays were open before sample collection; implant type (plate, rods, vs. polyetheretherketone), number of scrubbed personnel, and number of implants used were all not found to be significantly associated with implant contamination (p>.05). However, coverage of implants was found to significantly reduce the implant contamination rate (p=.016). ConclusionsThe contamination of sterile implants during spine surgery was found to occur. However, this contamination was independent of the amount of time the implant trays remained open. Coverage of implants significantly reduces this contamination. Therefore, no matter the expected duration of a case, implant coverage is a simple modifiable way to reduce the risk of intraoperative wound contamination and potentially reduce postoperative infections.

Technique is important for alcohol-based surgical hand antisepsis

Dear Editor, Surgical hand antisepsis (‘surgical scrubbing’) has been the topic of a recent article in this journal, as well as of several recent posts on the Australasian College for Infection Prevention and Control (ACIPC) email list ‘Infexion Connexion’. The article and the list discussion focused on the use of alcohol-based hand rubs for this purpose, which is a relatively new development in the Australian setting as opposed to ‘traditional’ surgical hand antisepsis with water and detergent-based antiseptics such as chlorhexidine or povidone–iodine antiseptic soaps. I would like to add another aspect to the discussion; this is the issue of correct technique, including appropriate hand and arm surface coverage, when using alcohols for surgical hand antisepsis. Alcohols for surgical hand antisepsis have three main advantages. First, they create far greater microbial reduction on hands and arms than is possible with any detergent-based antiseptics. In particular, products that meet the stringent European standard EN 12791, whereby an agent is compared to the reference of 60% (v/v) n-propanol, typically produce logarithmic (log) reductions between 2 and 3, with sustained values at 3 h under surgical gloves of around 2, where the baseline is normal resident hand flora before antisepsis. Second, alcohols with added emollients are generally better tolerated on hands and skin than detergents, particularly when frequent antisepsis is necessary. Third, the time requirements for alcohol-based antisepsis are shorter; most products require only 3min (this is also the time specified in standard EN 12791), and there are now newer products that achieve equivalent microbial reduction in only 1.5min of application. However, although microbiological principles and biological plausibility strongly support greater rather than lesser microbial reduction, so far there are no clinical trials showing that this translates into fewer surgical site infections. Alcohol-based as well as detergent-based surgical hand antisepsis has been incorporated into recent guidelines by the USCenters for Disease Control and Prevention (CDC), the Association of periOperative Registered Nurses (AORN) and the World Health Organization (WHO). There are two types of settings with regard to surgical hand antisepsis: (1) settings where alcohol-based agents have been predominantly or exclusively used for many decades, such as countries in central Europe, and (2) settings where detergentbased antisepsis has been the predominant method, such as Australia or the USA. In settings where something is frequently practised, in particular in the operating room environment, a practice becomes highly ritualised and is taught to new personnel and supervised (often fiercely) by experienced senior nurses or surgeons. Such practices then become engrained and assume elements that are not easily conveyed by textbooks or the scientific literature. In my own surgical internship in Germany, surgical hand antisepsis (termed ‘surgical hand disinfection’) was practised as follows. For the first procedure of the day, we did a hand and forearm wash with soap and water, including brushing or scraping only under the fingernails. Then, hands and forearms were dried using a sterile standard towel (remaining water on hands would compromise the efficacy of alcohol). This was followed by a 5-min alcohol hand rub (with a liquid product) whereby the alcohol was repeatedly and liberally dispensed from a wall-mounted, elbow-driven dispenser and rubbed onto hands and forearms, such that they were literally kept wet with alcohol and all surfaces covered for the entire period. The alcohol was then left to dry by evaporation. Current recommendations no longer require washing hands before using alcohol, and the application times have become shorter. The WHO guidelines state that prior hand washing is only necessary when hands are visibly dirty and that for most products, 3min of application are sufficient. The guidelines recommend approximately 3 5mL (total 15mL) for the procedure, but they emphasise that it is important to keep hands and arms wet during the entire procedure. In any case, this technique is fundamentally different from regular ward-based hand antisepsis according

Efficacy of antimicrobials for the disinfection of pathogen contaminated green bell pepper and of consumer cleaning methods for the decontamination of knives

While there is strong focus on eliminating pathogens from produce at a commercial level, consumers can employ simple methods to achieve additional pathogen reductions in the domestic kitchen. To determine the ability of antimicrobials to decontaminate peppers, samples of green bell pepper were inoculated with Salmonella enterica and Escherichia coli O157:H7 and then immersed in 3% (v/v) hydrogen peroxide (H2O2), 2.5% (v/v) acetic acid (AA), 70% (v/v) ethyl alcohol (EtOH), or sterile distilled water (SDW). The potential for transfer of pathogens from contaminated peppers to other non-contaminated produce items, and the effect of knife disinfection in preventing this cross contamination, were also tested. Knife disinfection procedures were evaluated by chopping inoculated peppers into 1cm2 pieces with kitchen knives. Experimental knives were then treated by either no treatment (control), wiping with a dry sterile cotton towel, rinsing under running warm water for 5 or 10s, or applying a 1% (v/v) lauryl sulfate-based detergent solution followed by rinsing with warm running water for 10s. Following disinfection treatment, knives were used to slice cucumbers. Exposure to H2O2 for 5min and EtOH for 1min resulted in reductions of 1.3±0.3 log10 CFU/cm2 for both pathogens. A 5min exposure to AA resulted in a reduction of S. enterica of 1.0±0.7 log10 CFU/cm2 and E. coli of 0.7±0.8 log10 CFU/cm2. No differences (p≥0.05) were found between numbers of pathogens on knives and numbers of pathogens transferred to cucumber slices, suggesting that organisms remaining on knife surfaces were transferred to cucumbers during slicing. Findings suggest that EtOH and H2O2 may be effective antimicrobials for in-home decontamination of peppers, and that use of detergent and warm water is effective for decontamination of implements used during meal preparation.

Prevention of Fire in the Dental Chair

Prevention of Fire in the Dental Chair

Fire in Labor and Delivery: Simulation Case Scenario

Fire in Labor and Delivery: Simulation Case Scenario

Daños ocasionados por el perforador del aguacate Heilipus lauri Boheman (Coleoptera: Curculionidae) en Tolima (Colombia)

El aguacate 'Hass' es un producto con potencial de exportación pero los daños presentados por insectos perforadores lo restringen para el norte del Tolima (Colombia). Para plantear su manejo se estableció la cría de la especie involucrada con frutos afectados individualmente. Se determinó el número de días en estado pupal para observar su morfología y determinar la magnitud de daño en el fruto y en la cosecha. Las cámaras de cría tipo tarrina o cajas tipo mantequillero fueron las más convenientes para la cría (P≤0,05) con suelo estéril o toalla absorbente y la desinfección del fruto con hipoclorito de sodio al 2%. La observación y confrontación de las características morfológicas externas de los especímenes con claves taxonómicas se encontró como Heilipus lauri Boheman (Coleoptera: Curculionidae). El insecto empupó a los 65,3±1,42 días, el estado pupal 15,14±0,33 días y la emergencia del 80,1±1,36 días. El daño en el fruto ocasionó una perforación en la epidermis con presencia de una costra circular negra, presencia de excretas blanquecinas y barrenación de la larva en pulpa y semilla. La evaluación en 12 árboles en producción para ocho fincas diferentes de Fresno y Herveo, registró el 0,03% y el 3,21% de daño (peso), respectivamente. El análisis de regresión múltiple (Stepwise) mostró que la cantidad de plateos/ año se correlaciona con el porcentaje de árboles infestados (P≤0,05 y r2 = 0,73).

Heightened Infection-Control Practices are Associated with Significantly Lower Infection Rates in Office-Based Mohs Surgery

Reported infection rates for Mohs micrographic surgery (MMS) range from less than 1% to 3.5%. To determine whether lower infection rates are possible for MMS with a consistently applied infection-control regimen. A series of 832 consecutive patients with 950 tumors undergoing MMS formed the cohort for a retrospective study of infections before and after a program of heightened infection-control practices at a single-surgeon academic Mohs practice. The sterility upgrade included jewelry restrictions, alcohol hand scrub before stages and reconstruction, sterile gloves and (during reconstruction) sterile gowns for staff, and sterile towels and dressings for patients during Mohs stages. Infection rate was 2.5% (9 infections/365 tumors) before the sterility upgrade and 0.9% (5 infections/585 tumors) after, a statistically significant difference (p=.04). MMS already has low rates of infection, but this study shows that rigorous infection-control practices can significantly affect infection rates. The authors have indicated no significant interest with commercial supporters.

A comparative study of two different hand-drying methods

Objective To provide clinical practice the simple,convenient and suitable hand-drying methods.Methods 64 clinical nurses were randomly divided into 2 groups.AIl of the subjects washed hands.One group members used disposable paper towels for drying hands after washing,and another group used sterile towels.Bacteria ntlmbers and the cost were compared between two groups.Results There were no significant differences between use of disposable paper towels and sterile towels in bacteria numbers and the cost of handaryins.Conclusions Disposable paper towels and sterile towels are both effective hand drying methods,but the former is more convenient and available. Key words: Clinical; Hand-drying; Methods; Effectiveness; Cost

Journal Scan: Journal of Pediatric Orthopaedics

Here is my view of the top-10 most potentially influential papers from the Journal of Pediatric Orthopaedics from 2007. Included are the papers that were thought to provide the most useful examinations of treatments and outcomes.

Time-Dependent Contamination of Opened Sterile Operating-Room Trays

There are no clear guidelines for how long a sterile operating-room tray can be exposed to the open environment before the contamination risk becomes unacceptable. The purpose of this study was to determine the time until first contamination and the rate of time-dependent contamination of sterile trays that had been opened in a controlled operating-room environment. We also examined the effect of operating-room traffic on the contamination rate. Forty-five sterile trays were opened in a positive-air-flow operating room. The trays were randomly assigned to three groups. All trays were opened with use of sterile technique and were exposed for four hours. Culture specimens were obtained immediately after opening and every thirty minutes thereafter during the study period. Group 1 consisted of fifteen trays that were opened and left uncovered in a locked operating room (i.e., one with no traffic). Group 2 was identical to Group 1 with the addition of single-person traffic flowing in and out of the operating room from a nonsterile corridor every ten minutes. Group 3 included fifteen trays that were opened, immediately covered with a sterile surgical towel, and then left uncovered in a locked operating room (i.e., one with no traffic). Three of the thirty uncovered trays (one left in the operating room with traffic and two left in the room with no traffic) were found to be contaminated immediately after opening. After those three trays were eliminated, the contamination rates recorded for the twenty-seven uncovered trays were 4% (one tray) at thirty minutes, 15% (four) at one hour, 22% (six) at two hours, 26% (seven) at three hours, and 30% (eight) at four hours. There was no difference in survival time (p = 0.47) or contamination rate (p = 0.69) between the uncovered trays in the room with traffic and those in the room without traffic. The covered trays were not contaminated during the testing period. The survival time for those trays was significantly longer (p = 0.03) and the contamination rate was significantly lower (p = 0.02) than those for the uncovered trays. Culture positivity correlated directly with the duration of open exposure of the uncovered operating-room trays. Light traffic in the operating room appeared to have no impact on the contamination risk. Coverage of surgical trays with a sterile towel significantly reduced the contamination risk.

First report of Phomopsis viticola causing bunch rot of grapes in Australia

From 2004 to 2006, grapevines (Vitis vinifera cv. Cabernet Sauvignon) in a commercial vineyard in the Hastings Valley (north eastern Australia) were surveyed for bunch rot diseases at dormancy, flowering, berries pea-sized, veraison and harvest. During the growing season black lesions were observed on green shoots and leaves. At harvest, abundant black pycnidia were consistently observed on the surface of bunches with berries becoming desiccated and rachis necrotic. Buds, canes, leaves, flowers and bunches were surface sterilized in 1% sodium hypochlorite for 1 min, followed by three successive washings in sterile distilled water. Isolations were initially made on Dichloran Rose Bengal Chloramphenicol agar and incubated at 25°C for 7 days. Any resulting fungal growth was sub-cultured onto potato dextrose agar and incubated at 25°C for 7 days. Phomopsis viticola was isolated from canes, leaves, flowers, rachis and bunches and identified based on morphological characteristics of the conidia. Koch's postulates were satisfied by inoculation of Cabernet Sauvignon berries from excised bunches taken at harvest. Whole bunches were surface sterilized by dipping in 1% sodium hypochlorite for 2 min, followed by three successive washings in sterile distilled water. Berries were inoculated with a 10 µL drop of 1 × 106 conidia per mL suspension. Control bunches were inoculated with 10 µL drops of sterile distilled water. Bunches were placed in plastic containers lined with sterile paper towel, moistened with sterile distilled water to maintain humidity and incubated at 23°C for 14 days. Black pycnidia developed on the surface that eventually sporulated to produce yellow oozing of spores. Phomopsis viticola was re-isolated from the pycnidia that had formed on the berries. Phomopsis viticola was first described as a rot of Niagara grapes in New York vineyards in 1911 by Gregory (1913), but is primarily recognised as a pathogen of the vegetative tissues. In Australia, P. viticola is a recognised pathogen of grapevine buds, canes, shoots and leaves (Merrin et al., 1995; Emmett et al., 1994). This is the first report of P. viticola causing bunch rot on grape in sub-tropical regions of Australia. Currently there are no fungicides registered for the control of phomopsis fruit rot of grape in Australia.

Paint-Only is Equivalent to Scrub-and-Paint in Preoperative Preparation of Abdominal Surgery Site

Conclusion: A paint with povidone-iodine by itself provides equal preoperative preparation of the abdominal wall as a scrub with povidone-iodine soap, followed by paint with povidone-iodine. Summary: The authors conducted a prospective randomized trial comparing scrub-and-paint with povidone-iodine soap followed by absorption with a sterile towel and subsequent paint with povidone-iodine versus surgical site preparation with paint only of povidone-iodine. The primary end point was wound infection at 30 days with wound infection defined as clinical signs of infection requiring therapeutic intervention. Excluded patients included those with active infection at the time of operation, known sensitivity to iodine, neutropenia, or insertion of prosthetic material during operation. Patients were randomized to a scrub-and-paint group or a paint only group with povidone-iodine. There were 115 patients randomized to the scrub-and-paint arm and 119 to the paint only arm of the trial. Patients were well matched with respect to surgical co-morbidities, age, operative time, drains, surgical procedure, and prophylactic antibiotic use. There were 12 wound infections in the scrub-and-paint patients (10%) and 12 wound infections in the paint only patients (10%). Comment: These data apply only to clean and clean-contaminated cases that do not involve placement of a prosthetic device. While the data are interesting, they do not provide guidance as to the proper surgical prep site technique for patients undergoing insertion of prosthetic grafts. The optimal surgical prep site technique with respect to insertion of prosthetic vascular grafts remains to be determined.

Paint-Only Is Equivalent to Scrub-and-Paint in Preoperative Preparation of Abdominal Surgery Sites

Antiseptic preoperative skin site preparation is used to prepare the operative site before making a surgical incision. The goal of this preparation is a reduction in postoperative wound infection. The most straightforward technique necessary to achieve this goal remains controversial. A prospective randomized trial was designed to prove equivalency for two commonly used techniques of surgical skin site preparation. Two hundred thirty-four patients undergoing nonlaparoscopic abdominal operations were consented for the trial. Exclusion criteria included presence of active infection at the time of operation, neutropenia, history of skin reaction to iodine, or anticipated insertion of prosthetic material at the time of operation. Patients were randomized to receive either a vigorous 5-minute scrub with povidone-iodine soap, followed by absorption with a sterile towel, and a paint with aqueous povidone-iodine or surgical site preparation with a povidone-iodine paint only. The primary end point of the study was wound infection rate at 30 days, defined as presence of clinical signs of infection requiring therapeutic intervention. Patients randomized to the scrub-and-paint arm (n = 115) and the paint-only arm (n = 119) matched at baseline with respect to age, comorbidity, wound classification, mean operative time, placement of drains, prophylactic antibiotic use, and surgical procedure (all p > 0.09). Wound infection occurred in 12 (10%) scrub-and-paint patients, and 12 (10%) paint-only patients. Based on our predefined equivalency parameters, we conclude equivalence of infection rates between the two preparations. Preoperative preparation of the abdomen with a scrub with povidone-iodine soap followed by a paint with aqueous povidone-iodine can be abandoned in favor of a paint with aqueous povidone-iodine alone. This change will result in reductions in operative times and costs.

Limb Lengthening for Stature: Another View

Limb Lengthening for Stature: Another View

Surgical pearl: the use of towel clamps to reapproximate wound edges under tension

The science of wound repair is a continuously expanding world of new techniques and technology. The primary repair of high-tension defects, however, remains one of the greatest challenges in attaining ideal cosmesis. Tension hinders the accurate reapproximation of the wound edges and makes placement of the initial buried sutures difficult. Methods to overcome mechanical forces include the placement of horizontal mattress sutures along with padding material on the exposed sutures to distribute the tension.1 A modified vertical mattress suture with a pulley is also effective.2 Other fascinating methods include immediate balloon expansion or suture tension adjustment where the tissue is expanded intraoperatively with a balloon or metal clasp for skin recruitment in repair of large defects. Although all these methods are effective, they can be effort intensive and time consuming. A towel clip is a clamp with 2 sharp edges at 60-degree angles that lock together when closed. Other than the obvious use in maintaining the position of sterile towels, it can be used as a quick and effective method of reapproximating the cutaneous surface.

Septic arthritis following intra-articular steroid injection of the knee--a survey of current practice regarding antiseptic technique used during intra-articular steroid injection of the knee.

Septic arthritis is a potential catastrophic complication of intra-articular steroid injection. There is lack of evidence regarding the precautions that should be taken to avoid such a complication, as well as how often it is encountered. The aim of this study was to evaluate the antiseptic precautions taken during intra-articular steroid injection of the knee in the United Kingdom (UK), and estimate how often septic arthritis is encountered by health professionals in the UK following steroid injection of the knee. A questionnaire was posted to 100 orthopaedic surgeons, 100 rheumatologists and 50 general practitioners (GPs), asking them about the cases of septic arthritis following intra-articular steroid injection of the knee that they encountered during their practice and the precautions they take when injecting knees. The response rate was 76.4%; 57.6% of the respondents used alcohol swabs to clean the skin, and the remaining 42.4% used chlorhexidine or Betadine. Only 16.3% used sterile towels to isolate the injection site. There were 32.5% of respondents who routinely used sterile gloves when injecting, and a total of 46.6% used either sterile or non-sterile gloves. Also, 91.1% changed needles between drawing the steroid and injecting it into the joint. Only 24 respondents (12.6%) had encountered septic arthritis after steroid injection of the knee (18 once, 3 twice, 2 three times, 1 several times). We concluded that septic arthritis post intra-articular steroid injection of the knee is probably rare. There is a wide variation in the precautions taken to avoid such a complication. However, the trend seems to be towards minimal use of antiseptic techniques. Further large prospective studies are needed to determine how frequently septic arthritis of the knee is encountered post steroid injection, and the exact precautions that should be taken to avoid it.

Reducing Salmonella on Apples with Wash Practices Commonly Used by Consumers

The efficacy levels of practices used by consumers to wash smooth-surface fruits and vegetables were compared. Golden Delicious apples were spot inoculated near the blossom end with 50μl of a cocktail of six serotypes of Salmonella enterica (with a total inoculum level of approximately 109 CFU per apple). The inoculum was dried for 1.5 h, and apples were either treated immediately or held for 24 h prior to treatment. Treatments included wetting with approximately 5 ml of water, vinegar (5% acidity), or a 200-ppm chlorine solution, rubbing for 5 or 30 s, rinsing with 200 to 600 ml of 24 or 43°C water, and drying with a sterile paper towel. Residual populations of Salmonella were determined by rubbing the treated apple for 30 s in 20 ml of Dey-Engley neutralizing broth and plating on tryptic soy agar and bismuth sulfite agar. Rubbing treatments carried out for 5 and 30 s both resulted in a significant reduction in Salmonella populations (1 log10 CFU per apple) relative to populations on samples held for 30 s. A 5-s rub followed by a 200-ml flowing-water rinse reduced populations by 3 log10 CFU per apple. No further decrease in population was obtained by rinsing with 400 or 600 ml of water. Increasing the rinse water temperature to 43°C did not significantly improve microbial removal. Drying the apple with a sterile paper towel resulted in an additional decrease of approximately 0.4 log10 CFU per apple. A reduction of 3.2 log10 CFU was achieved with a combination of wetting with water, rubbing for 5 s, rinsing with 200 ml of water, and drying with a paper towel for apples inoculated just prior to or 24 h before treatment. Reductions obtained for apples treated with 5% vinegar and with a 200-ppm chlorine solution were significantly larger (2.1 to 3.2 log10 CFU per apple, respectively) than those achieved with water.

Mitral valve replacement in patients with mitral annulus abscess

R of the mitral valve in the presence of an abscess of the mitral annulus presents a major challenge to the surgeon. The patients involved are frequently very ill as a result of uncontrolled infection as well as hemodynamic compromise because of valve dysfunction. They frequently have severe coagulation derangements before surgery. It is not surprising that surgery in these patients is associated with a relatively high mortality and complication rate. However, a carefully planned surgical approach offers these patients the best chance of survival. There are two fundamental principles that a surgeon must adhere to in treating these patients. The first one is that all of the infected valvular and perivalvular material must be removed before a new prosthesis is secured in place. Failure to do this will invariably result in reinfection of the new valve prosthesis as well as the surrounding annulus. Once all the infected material is removed, the surgical team should change their gown and gloves. All instruments used to remove the infected material are discarded, and new sterile towels placed around the open wound. Complete removal of all of the infection, especially the infected annular tissue, will often leave insufficient annulus to which a new valve can be secured. This leads to the second principle, which is to carefully reconstruct the annulus before sewing in a new valve. Simply attempting to secure a new valve into a partially destroyed annulus will either result in immediate and usually fatal atrial ventricular disassociation or to early valve dehiscence. The following outlines the surgical steps that we recommend for management of the infected mitral annulus. The simplest repair applies to the case where only one part, usually the posterior part, of the annulus is involved. A more complex repair, which is really an extension of the simplest repair, is required if the entire circumferential annulus is infected, as is often the case with a previously inserted infected prosthetic valve. Finally, if the infection is so extensive so that not only is the mitral annulus destroyed but also part of the aortic annulus and the central fibrous body, an extensive and complex reconstruction is required. We will review the surgery for the first two conditions. Further details regarding the most complex reconstruction are outlined in previously published articles.1,2

Hospital policy for prevention of infection after neuraxial blocks in obstetrics

Even though most regional anesthesia textbooks and articles about infectious complications associated with central neuraxial blocks underline the necessity of surgical asepsis, none offers a clear and precise procedure. This protocol is intended to reduce variability of practices, and is felt to be stringent enough to be effective and liberal enough to be fully implemented. Any person involved with the procedure must wear a cap and a new face mask. The patient also should wear a cap. The anesthesiologist, wearing his usual operating room clothing, must wash his hands with an antiseptic soap solution, dry them on a sterile towel and wear sterile gloves. The patient's back should be disinfected at least twice (alcohol-iodine, alcoholic solution of chlorhexidine or of povidone-iodine). Disposable equipment only must be used. Drugs must be prepared contemporaneously and in a sterile manner (collar of non-sterilized ampoules cleaned with alcohol). The solution is drawn up through the filter (contained in the epidural set) but injected after filter removal. Infusion of sterile mixtures is preferable to top-ups, which require frequent disconnections that may cause hub colonization. Manipulation of the hub of the catheter must be preceded both by antiseptic hand washing and by swabbing with sterilized gauze soaked with 70% alcohol. Catheter removal requires only antiseptic hand washing in most circumstances. Wearing mask and gloves and improving skin disinfection practices are believed to be the more important parts of this protocol.

Surface Colonization, Penetration, and Lesion Formation on Grapes Inoculated Fresh or After Cold Storage with Single Airborne Conidia of Botrytis cinerea.

Infection of grapes by different densities of airborne conidia of Botrytis cinerea was investigated on table grapes (cultivar Dauphine) harvested ripe (16°Brix) and inoculated fresh, or after SO2 treatment and 8-week storage at -0.5°C. Berries were detached at each inoculation and dusted with dry conidia in a settling tower. Following inoculation, the fresh berries were incubated for 24 h at high relative humidity (≥93%), or were overlaid with wet sterile paper towels. Cold-stored berries were incubated at high relative humidity. The effect of conidial density on surface colonization, penetration, and lesion formation was determined by surface sterilization, isolation, and freezing studies on fresh berries. Only symptom expression was determined on cold-stored berries. Fluorescence microscopy of skin segments showed that conidia were consistently deposited as single cells, and not in pairs or groups, on berry surfaces. Individual conidia, at all densities tested, readily infected the cold-stored berries and formed separate lesions after 2 days. Although the cold-stored berries were highly susceptible, lesion numbers were not related to conidial density at low inoculum dosages (0.67 to 2.60 conidia per mm2 berry surface). Lesion numbers tended to increase exponentially at higher dosages (3.24 to 3.88 conidia per mm2 berry surface). Individual conidia, however, did not induce any disease symptoms on fresh berries. Removal of the pathogen after 24-h incubation from the surface of fresh berries by ethanol, and subsequent incubation of excised skin segments revealed that, irrespective of the conidial density or the wetness regime, less than 2% of skin segments were penetrated. Furthermore, increasing densities of conidia did not lead to higher rates of surface colonization and skin penetration. The low incidence of disease caused on fresh berries and high disease incidence induced after prolonged cold storage indicated that infection was not governed by conidial density on berry surfaces, but by the level of host resistance.