Electronic particle counting for evaluating the quality of air in operating theatres: a potential basis for standards?

Airborne particle counting in eight size ranges (0.5- greater than 20 microns), by computerized electronic equipment, was compared with the numbers of bacteria-carrying particles (BCP) assessed by slit sampling in ultra-clean and turbulently ventilated operating theatres. In the ultra-clean theatre the number of particles of 5-7 microns size range correlated with BCP while peaks in the numbers of particles less than 3 microns and greater than 15 microns corresponded with activity. Comparative relationships also occurred in the turbulently ventilated theatre but the use of this equipment in that environment cannot yet replace counts of airborne bacteria. We consider that electronic particle counting in the 0-20 microns size range may be used to judge the performance of a clean air operating theatre distribution system, including efficiency and integrity of the filter/seal systems and the presence or absence of entrainment of bacteria and other particles. The sampling techniques and analysis of particle concentration results described here may be a suitable basis for standards.     

Electronic particle counting for evaluating the quality of air in operating theatres: a potential basis for standards?

Airborne particle counting in eight size ranges (0.5 → 20 μm), by computerized electronic equipment, was compared with the numbers of bacteria-carrying particles (BCP) assessed by slit sampling in ultra-clean and turbulently ventilated operating theatres. In the ultra-clean theatre the number of particles of 5–7 μm size range correlated with BCP while peaks in the numbers of particles <3 μm and > 15 μm corresponded with activity. Comparative relationships also occurred in the turbulently ventilated theatre but the use of this equipment in that environment cannot yet replace counts of airborne bacteria. We consider that electronic particle counting in the 0–20 μm size range may be used to judge the performance of a clean air operating theatre distribution system, including efficiency and integrity of the filter/seal systems and the presence or absence of entrainment of bacteria and other particles. The sampling techniques and analysis of particle concentration results described here may be a suitable basis for standards.     

Effects of different protective clothing for reducing body exposure to chlorothalonil during application in cucumber greenhouses

Occupational exposure safety remains a major issue during greenhouse spray applications in China. Herein, we tested the safety of 2 protective clothing types to be used in cucumber greenhouses: 100% cotton hooded coveralls and non-woven fabric hooded coveralls. A hand-operated knapsack sprayer was used for chlorothalonil application (75% WP). The whole-body dosimetry technique was used to collect dermal exposure samples, including gloves and socks. In the absence of any personal protective equipment (PPE), chlorothalonil application resulted in a total dermal exposure of 5759.5 μg/h. When 100% cotton hooded coveralls (including single-layer gloves) and non-woven fabric hooded coveralls (including rubber gloves) were used as protective measures, the total dermal exposures of the applicators were 5759.5 and 2511.3 μg/h, representing deflection rates of 88.7 and 95.1% of the total dermal exposure in the absence of PPE, respectively. Next, dermal exposure when using 2 cotton garment layers (100% cotton hooded coverall as the outer-layer garment and 85% cotton underwear as the inner-layer garment) was analyzed. The penetration rate of the outer-layer garment was first estimated; the penetration rate for the left lower leg section was 1.8% (the lowest), and that of the chest section was 12.1% (the highest), with a mean penetration rate of 6.3%. When a single-layer 100% cotton coverall (including 100% cotton gloves) and a non-woven fabric coverall (including rubber gloves) were used as protective measures, the main exposure site among the applicators was the face (including the neck). Thus, to reduce the exposure risk of farmers during chlorothalonil application, it is essential to strengthen protective clothing and improve protection for the face (including the neck), which is often exposed. Moreover, it is essential to improve knowledge on occupational safety and self-protection measures among farmers. These findings may provide useful information for risk mitigation and management and epidemiological studies in China.     

Effect of ultraclean air in operating rooms on deep sepsis in the joint after total hip or knee replacement: a randomised study.

In a multicentre study of sepsis after total hip or knee replacement the operations performed by each surgeon were allocated at random between control and ultraclean-air operating rooms. Records were obtained from over 8000 such operations. In the patients whose prostheses were inserted in an operating room ventilated by an ultraclean-air system the incidence of joint sepsis confirmed at reoperation within the next one to four years was about half that of patients who had had the operation in a conventionally ventilated room at the same hospital. When whole-body exhaust-ventilated suits had been worn by the operating team in a theatre ventilated by an ultraclean-air system the incidence of sepsis was about a quarter of that found after operations performed with conventional ventilation. When all groups in the trial were considered together the analysis showed deep sepsis after 63 out of 4133 operations in the control group (1.5%) and after 23 out of 3922 operations in the ultraclean-air groups (0.6%) (ratio 2.6, 95% confidence limits 1.6-4.2; p less than 0.001). The design of the study did not include a strictly controlled test of the effect of prophylactic antibiotics, but their use was associated with a lower incidence of sepsis than in patients who had received no antibiotic prophylaxis at their operations (0.6% (34/5831) v 2.3% (52/2221); ratio 4.0).     

一株高效聚磷解淀粉芽孢杆菌的分离鉴定及其除磷条件优化

【背景】磷是引起水体富营养化的主要营养物质。生物除磷具有成本低、效率高且适用范围广等特点,成为近年来水处理研究领域的热点。目前虽然有一些聚磷菌被筛选获得,但它们的除磷效率不高,其除磷条件尚需优化。聚磷菌的固定化及回收利用也亟待研究。【目的】分离筛选并鉴定高效聚磷菌株,优化除磷环境条件,研究吸附材料对所筛菌株除磷的影响,为聚磷菌的开发利用提供理论依据。【方法】采用常规细菌分离筛选方法获得高效菌株,通过形态特征观察、生理生化实验和16S rRNA基因序列分析对菌株进行鉴定;结合单因素试验、Box-BehnkenDesign和响应面分析优化除磷条件;通过测定海绵、无纺布和聚氨酯泡沫对聚磷菌的吸附作用评估该材料的固定化效果。【结果】从连云港市某磷矿厂废水中分离筛选出一株高效聚磷细菌P49,经鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens);优化后的最佳除磷条件为pH 6.8、温度31℃、装液量30.2%,在此条件下P49除磷率可达80.43%;应用聚氨酯泡沫的吸附效果优于海绵和无纺布。【结论】解淀粉芽孢杆菌P49具有良好的除磷效果,可为生物除磷提供微生物资源,用聚氨酯泡沫吸附可实现对该菌株的固定化和回收利用。     

Chitin induces type IV collagen and elastic fiber in implanted non-woven fabric of polyester

The non-woven fabric of polyester (control) and the composite material of the non-woven fabric of polyester and chitin (Chitipack P) were implanted to bovine flexor tendon. After 3 weeks implantation, type IV collagen and elastic fibers were significantly increased and type I collagen was decreased in Chitipack P in comparison with control. The breaking strength was about twice as high in Chitipack P than in control. The polykaryocytes in the control were more difficult to digest for the collagens. Angiogenesis in the implanted non-woven fabric and in the neighboring resected tendons was much stronger in Chitipack P. Chitin induced type IV collagen and elastic fibers in the prostheses.     

Effect of separator and inoculum type on electricity generation and microbial community in single-chamber microbial fuel cells

Single-chamber microbial fuel cell (SMFC)-I consisted of 4 separator-electrode assemblies (SEAs) with two types of cation exchange membrane (CEM: Nafion and CMI 7000) and an anion exchange membrane (AEM: AMI 7001). SMFC-II consisted of 4 SEAs with Nafion and three types of nonwoven fabric. SMFC-I and -II were inoculated with anaerobic digested and activated sludge, respectively, and operated under fed-batch mode. In SMFC I, AEM-SEA showed a maximum power density (PD_max). Nafion-SEA showed a PD_max in SMFC II, which was similar to that of Nafion–SEA of SMFC I. Although different bacteria were developed in SMFC-I (Deltaproteobacteria and Firmicutes) and SMFC-II (Gammaproteobacteria, Betaproteobacteria and Bacteroidetes), the inoculum type little affects electricity generation. Variations of pH and oxygen in biofilm have influenced microbial community structure and electricity generation according to the electrode and separator material. Although the electricity generation of non-woven fabric-SEA was less than that of Nafion-SEA, the use of non-woven fabrics is expected to reduce the construction and operating costs of MFCs.     

Comparative Enumeration of Lipophilic and Nonlipophilic Cutaneous Diphtheroids and Cocci

Swabbing skin to collect bacteria for enumeration revealed that a single washing or rinsing of the swab in buffer removed between 90 and 95% of the bacteria collected. Further removal of the remaining bacteria from the initial swab by repeated washings of the swab produced plate counts that showed nearly proportional decreases in the numbers and types of bacteria retained or eluted from the swab. None of the commonly isolated cutaneous bacteria was retained or eluted from the single swab in numbers that misrepresented measurement of their proportions present in the sample. Populations of nonlipophilic bacteria on skin when present were mainly gram-positive catalase-producing cocci. Diphtheroids when present were chiefly lipophilic. Media containing furoxone were selective for cutaneous diphtheroids. The concentration of furoxone used affected isolation and enumeration of the diphtheroids. Lipophilic diphtheroids from the stratum corneum were basically aerobic and anaerobic incubation reduced or eliminated this group from enumeration studies. Lipophilic furoxone-resistant aerobic diphtheroids from several areas, particularly the nasal passages, occurred in numbers inversely proportional to the numbers of staphylococci for periods up to 11 months. The cocci-diphtheroid relationships occurred independently of the total number of aerobic bacteria present, the transient appearance of yeasts or gram-negative bacilli, the required use of certain antibiotics by the subjects, climate, age, and sex.     

Cometabolism of m-Chlorobenzoate by an Arthrobacter

Swabbing skin to collect bacteria for enumeration revealed that a single washing or rinsing of the swab in buffer removed between 90 and 95% of the bacteria collected. Further removal of the remaining bacteria from the initial swab by repeated washings of the swab produced plate counts that showed nearly proportional decreases in the numbers and types of bacteria retained or eluted from the swab. None of the commonly isolated cutaneous bacteria was retained or eluted from the single swab in numbers that misrepresented measurement of their proportions present in the sample. Populations of nonlipophilic bacteria on skin when present were mainly gram-positive catalase-producing cocci. Diphtheroids when present were chiefly lipophilic. Media containing furoxone were selective for cutaneous diphtheroids. The concentration of furoxone used affected isolation and enumeration of the diphtheroids. Lipophilic diphtheroids from the stratum corneum were basically aerobic and anaerobic incubation reduced or eliminated this group from enumeration studies. Lipophilic furoxone-resistant aerobic diphtheroids from several areas, particularly the nasal passages, occurred in numbers inversely proportional to the numbers of staphylococci for periods up to 11 months. The cocci-diphtheroid relationships occurred independently of the total number of aerobic bacteria present, the transient appearance of yeasts or gram-negative bacilli, the required use of certain antibiotics by the subjects, climate, age, and sex.     

Response to trisodium phosphate treatment of Salmonella Chester attached to fresh-cut green pepper slices

A laboratory model using green pepper disks was developed to investigate the attachment of Salmonella Chester on plant tissue and to evaluate the effectiveness of sanitizer agents in inactivating attached bacteria on fruits. Pepper disks (14 mm in diam, and 3-4 mm in thickness) were immersed in a bacterial suspension containing 1.5 x 107 cfu x mL(-1) of S. Chester for 30 s and subsequently air-dried at room temperature for 10 min. Approximately 30% of the bacteria retained on the disk after immersion were firmly attached and could not be removed by two washes and agitation. A positive correlation was observed between the number of bacteria attached and the concentration of bacteria in the suspension. Population studies and scanning electron microscopic examinations revealed that attachment of S. Chester on pepper disks occurred mainly on the surfaces of injured (cut) tissue but rarely on the unbroken skin. When inoculated disks were treated with 3% to 12% (w/v) of trisodium phosphate (TSP) at pH 12.3 for 5 min, the population of bacteria on the disk was reduced by 10- to 100-fold. A small portion (0.7% to 7.1%) of bacteria attached to the disk were either resistant to or protected from the TSP treatment. When the pH of TSP solution was reduced from 12.3 to 4.5, the effectiveness of TSP in inactivating S. Chester on pepper disks was reduced by 26%. This study shows that surfaces of injured fruit tissue are the principal sites for bacterial attachment, and a small portion of the bacteria attached to the tissue are resistant to the sanitizer treatment. Avoiding mechanical injuries to fresh fruits during and after harvest would reduce the chance of pathogen attachment and contamination on green pepper and fruits of similar nature.     

Can nocturnal emergency surgery be reduced?

A prospective study of emergency operations was performed over three months in a district general hospital. Before starting surgery surgeons completed a questionnaire recording clinical details together with time of admission and were asked to state whether in their opinion the case could be safely deferred until the next morning assuming operating time was available. Of 251 operations performed, forms were completed for 244. According to the surgeons, 62 could have been safely deferred, and subsequent independent analysis indicated a further 24 could also have been safely postponed, giving a total of 86 cases (35%). Of the remainder, 71 were started between 2300 and 0900, and of these 51 (71%) were major operations requiring an experienced surgeon. The results suggest that, although the volume of nocturnal major surgery could not be reduced, the introduction of a daily emergency theatre session for cases seen during the day and those which could be deferred from the previous night would appreciably reduce the overall workload of nocturnal surgery at present done by the resident junior staff. This study will have important implications if, as has been suggested, the number of junior medical staff on call at night for emergencies is reduced.     

The importance of dispersal for bacterial community composition and functioning

We conducted a metacommunity experiment to investigate the role of dispersal for bacterial community composition (BCC) and function of freshwater bacteria. Bacteria were dispersed from a common source pool into three different lake communities in their natural lake water. The experiment was conducted in dialysis bags to enable a decoupling between a change in the local environment and dispersal. BCC was determined by terminal restriction fragment length polymorphism (tRFLP) of the 16S rRNA gene. We show that the greatest changes in BCC occurred between 10% and 43% of dispersal of standing stock per day. Functioning, measured as growth rate, was also affected by dispersal in all three communities but the qualitative pattern differed between communities, sometimes showing a hump-shaped relationship to dispersal and sometimes decreasing with increasing dispersal. In all waters, functioning was related to BCC. Our results show that dispersal does affect BCC and functioning but that high dispersal rates are needed. Further, the effect of dispersal on BCC and function seem to depend on the quality of the habitat to which bacteria disperse into.     

Importance of dynamics of sweating in men during exercise

Influence of dynamics of sweating on rectal temperature increase was tested in 3 groups of men performing cycle exercise with intensity of 65, 90 and 120 W, respectively, in 22 degrees C chamber temperature and 30% of relative air humidity. During exercise at 65 and 90 W the subjects wore suits while exercising with intensity of 120 W they wore only shorts. The dynamics of sweating was described by delay in onset of sweating and time constant of the reaction. Wearing caused significant increase in skin humidity and decreased evaporative rate of sweating. Sweat rate during steady state was related to the metabolic rate in naked (r = 0.89, p less than 0.002) as well as in wearing subjects (r = 0.93, p less than 0.01). Delay in onset of sweating was, in average, 5 min with a time constant of 7 min. Both factors showed a tendency to be shorter with increasing work intensity. Mean increase in rectal temperature was proportional to the intensity of exercise although the individual delta Tre correlated well with the dynamics of sweating in naked (r = 0.83, p less than 0.01) and wearing subjects (r = 0.84, p less than 0.01). Since delta Tre was smaller in subjects with shorter inertia time of sweating in response to beginning of exercise at the same intensity it is concluded that the dynamics of sweating can play an important role in limiting body temperature increase in working men.     

海豚链球菌诱变发酵法制备透明质酸及其在动物皮肤修复中的应用

透明质酸(HA)是一种非常重要的生物材料,是体内广泛存在的细胞外基质成分之一。为了获得产量、分子量及纯度较高的透明质酸,并研究透明质酸水凝胶在动物皮肤修复中的潜在作用。通过紫外诱变的方法对海豚链球菌进行诱变,并对此突变菌发酵后产物的蛋白含量及HA分子量进行了测定,通过CTAB法对发酵产物进行提纯,运用物理冻融法将透明质酸制成水凝胶后,用于兔背部全层皮肤修复的初探。结果表明通过诱变海豚链球菌产透明质酸的能力从(82.3±3.3)mg/L增加到(120±10.6)mg/L,增加了46.4%;产物经纯化后蛋白含量从(0.178±0.011)mg/L减少到(0.032±0.017)mg/L,减少了82.02%;所制得透明质酸的分子量约为3.0×105 Da;透明质酸水凝胶对兔全层皮肤缺损的修复有较明显的促进作用,能减轻炎症和伤口瘢痕的形成。     

Influence of swimsuit design and fabric surface properties on the butterfly kinematics

This study investigated the influence of the covering swimsuit and the fabric surface properties on the butterfly stroke kinematics. Surface properties were evaluated by wetting measurements of two fabric samples: one for training suits and one for competition suits. The surface of the second one was coated by mechanochemical treatment in order to modify its surface properties. Nine national level swimmers performed a 50-m butterfly at submaximal velocity in three swimsuit conditions: conventional, long, and coated long swimsuits. From video recording, the hip was digitized at the entry and exit of the swimmer's hand in order to calculate the duration, hip displacement, and hip linear velocity during underwater and recovery phases and during stroke. The results for wetting show that competition fabric was more water-repellent than training fabric, but both were isotropic. Moreover, the mechanochemical treatment increased water repellency and anisotropy. The swimming results indicated that, when compared to a conventional swimsuit, wearing a coated long swimsuit increased hip linear velocity during stroke, and particularly during the recovery phase which had a shorter duration. These results suggest that the covering swimsuit should be coupled with the water repellent and anisotropic properties of the fabric surface in order to improve swimming performance.     

应用球孢白僵菌菌条持续控制松褐天牛效果的分子评价

采用Ⅰ型内含子技术对应用球孢白僵菌无纺布菌条持续控制松褐天牛的防治效果进行了分子生物学评价.结果表明: 采用常规手段评价防治效果,两个处理区的防治效果分别为19.5%和10.8%; 而采用分子手段进行评价,防治效果分别为14.2%和11%.证明常规评价以死亡率或侵染率来计算微生物防治效果,难以排除当地微生物区系中的土著菌株所造成的侵染死亡,而采用分子生物学手段进行防治效果评价可从一定程度上消除土著菌株的干扰,较准确地反映人工放菌的防治效果.     

Spatial and Temporal Variation in Hydrochory in Amazonian Floodplain Forest1

ABSTRACT The hypothesis that water depth, plant species, and the presence of submerged substrates influence seed dispersal by water was tested in a whitewater tributary of the Tocantins River of the Amazon Basin. Seed dispersal was greatest when water depth was greatest, which occurred during the new moon. Seeds of buoyant species with smaller seeds required less water for dispersal than large seeded species. Submerged objects reduced the distance dispersed but not the probability of dispersal.     

Can Particulate Air Sampling Predict Microbial Load in Operating Theatres for Arthroplasty?

Several studies have proposed that the microbiological quality of the air in operating theatres be indirectly evaluated by means of particle counting, a technique derived from industrial clean-room technology standards, using airborne particle concentration as an index of microbial contamination. However, the relationship between particle counting and microbiological sampling has rarely been evaluated and demonstrated in operating theatres. The aim of the present study was to determine whether particle counting could predict microbiological contamination of the air in an operating theatre during 95 surgical arthroplasty procedures. This investigation was carried out over a period of three months in 2010 in an orthopedic operating theatre devoted exclusively to prosthetic surgery. During each procedure, the bacterial contamination of the air was determined by means of active sampling; at the same time, airborne particulate contamination was assessed throughout the entire procedure. On considering the total number of surgical operations, the mean value of the total bacterial load in the center of the operating theatre proved to be 35 CFU/m³; the mean particle count was 4,194,569 no./m³ for particles of diameter ≥0.5 µm and 13,519 no./m³ for particles of diameter ≥5 µm. No significant differences emerged between the median values of the airborne microbial load recorded during the two types of procedure monitored. Particulates with a diameter of ≥0.5 µm were detected in statistically higher concentrations (p<0.001) during knee-replacement procedures. By contrast, particulates with a diameter of ≥5 µm displayed a statistically higher concentration during hip-replacement procedures (p<0.05). The results did not reveal any statistically significant correlation between microbial loads and particle counts for either of the particle diameters considered (≥0.5 µm and ≥5 µm). Consequently, microbiological monitoring remains the most suitable method of evaluating the quality of air in operating theatres.     

Isolation of ultrasmall (filterable) bacteria from patients suffering from ME,and patients and staff of a paediatric hospital

A total of 108 blood samples obtained from 28 male and 80 female patients diagnosed with ME were diluted in sterile, Ringer’s Solution and forced (by suction) through 0.2 µm filters. Of the 28 male samples, 4 yielded filterable bacteria and of the 80 female samples, 18 gave filterable bacteria; as a result, of the total of 124 samples, 22 yielded FB. Filterable (0.4 and 0.2, but not 0.1micron filterable) bacteria were also isolated from the nose throat and skin of paediatric patients and from the throat and skin of staff at an emergency paediatric hospital. The highest percentage of bacterial passage occurred through the largest (0.4 µm) pores. The results show that ultrasmall bacteria occur in ME patients and in paediatric patients and nurses. The potential pathogenic role of such filterable bacteria is briefly discussed.     

Mass Airflow Cabinet for Control of Airborne Infection of Laboratory Rodents

A mass airflow cabinet for handling and housing of laboratory rodents has been developed and tested. The unit consists of a high-efficiency particulate air filter and uniform distribution of air at a vertical velocity of 19 cm per s. Animals are maintained without bedding in mesh-bottomed cages that rest on rollers for rotation inside the cabinet. There is an air barrier of 90 cm per s separating the cabinet air from room air. Sampling for airborne bacteria yielded an average of 0.03 colony-forming units (CFU) per ft(3) of air inside the cabinet, whereas 28.8 CFU per ft(3) was simultaneously detected outside the cabinet during housekeeping, a reduction of almost three logs. The efficiency of the air barrier was tested by aerosolization of T3 phage. When phage was aerosolized 5 cm outside the cabinet, no phage could be detected 5 cm inside when the fans were operating; with the fans off an average of 1.6 x 10(4) plaque-forming units (PFU) per ft(3) was detected in six tests. Aerosolization of phage inside the cabinet yielded an average of 9 x 10 PFU per ft(3) outside; an average of 4.1 x 10(6) PFU per ft(3) were detected with the fans not in operation, a reduction of more than four logs. In-use studies on effectiveness showed that the cabinet significantly reduced the incidence of mice originally titer-free to Reo-3 virus. Hemagglutination inhibition antibodies to Reo-3 were detected in 9/22 (42%) mice housed in a conventionally ventilated animal laboratory while no seroconversion was detected in any of 22 mice housed in the mass air flow cabinet in the same laboratory.