Number Of Viable Organisms Research Articles

Potential transfer of aquatic organisms via ballast water with a particular focus on harmful and non-indigenous species: A survey from Adriatic ports

Ballast water discharges may cause negative impacts to aquatic ecosystems, human health and economic activities by the introduction of potentially harmful species. Fifty untreated ballast water tanks, ten in each port, were sampled in four Adriatic Italian ports and one Slovenian port. Salinity, temperature and fluorescence were measured on board. Faecal indicator bacteria (FIB), phyto- and zooplankton were qualitatively and quantitatively determined to identify the species assemblage arriving in ballast water. FIB exceeded the convention standard limits in 12% of the sampled tanks. Vibrio cholerae was not detected. The number of viable organisms in the size groups (minimum dimension) <50 and ≥10 μm and ≥50 μm resulted above the abundances required from the Ballast Water Management Convention in 55 and 86% of the samples, respectively. This is not surprising as unmanaged ballast waters were sampled. Some potentially toxic and non-indigenous species were observed in both phyto- and zooplankton assemblages.

Biotesting of plasma-chemically activated water with the use of hydrobionts

The study has determined the influence of plasma-chemically activated water and its level of toxicity on test objects. It has been established that the reaction of biological objects is positive, which is reflected in their livelihood. The obtained research results show that the nature of the influence of water of different structures on the species composition of the selected test objects depends on the individual properties of each of them. The influence of plasma-chemically activated water on the functional properties of Riccia fluitans, L e mna m i nor L., Paramecium с audatum, Artemia salina and Cyprinus carpio has been investigated. The completed tests have helped supplement and substantiate the already existing idea about the properties of the plasma-chemically activated water and the possibilities of its use in the processing of raw materials and the manufacturing of finished products. In the course of the research, it was found that the Paramecium с audatum survival was 87–89.5 %, with no toxic effects of the plasma-chemically activated water on these objects. The cultivation of Artemia salina in water that had been pre-treated by the proposed method showed that the number of viable organisms had increased by 60–70 % compared with the reference. The obtained results of studying the influence of the plasma-chemically activated water on the development of Riccia fluitans and L e mna m i nor L. indicate that the activation of growth processes is 7–39 % higher than in the reference. It has been determined that the cultivation of Cyprinus carpio in the treated water contributes to increasing the survival rate as it improved the test objects by 13 % and 6 %, respectively, as to the reference. Using the method of gas-discharge diagnostics has shown that the treatment of water with nonthermal plasma for 30 minutes contributes to increasing its biopotential. Consequently, the obtained results indicate the expediency of using plasma-chemically activated water for the production of food and feed. The established positive changes support information on the safety of using plasma-chemically activated water as a component of the food chain and prove the practical value of a comprehensive approach to innovative methods of preparing raw materials.

Examination of an indicative tool for rapidly estimating viable organism abundance in ballast water

Regulatory discharge standards stipulating a maximum allowable number of viable organisms in ballast water have led to a need for rapid, easy and accurate compliance assessment tools and protocols. Some potential tools presume that organisms present in ballast water samples display the same characteristics of life as the native community (e.g. rates of fluorescence). This presumption may not prove true, particularly when ships' ballast tanks present a harsh environment and long transit times, negatively impacting organism health. Here, we test the accuracy of a handheld pulse amplitude modulated (PAM) fluorometer, the Hach BW680, for detecting photosynthetic protists at concentrations above or below the discharge standard (<10 cells·ml−1) in comparison to microscopic counts using fluorescein diacetate as a viability probe. Testing was conducted on serial dilutions of freshwater harbour samples in the lab and in situ untreated ballast water samples originating from marine, freshwater and brackish sources utilizing three preprocessing techniques to target organisms in the size range of ≥10 and <50μm. The BW680 numeric estimates were in agreement with microscopic counts when analyzing freshly collected harbour water at all but the lowest concentrations (<38 cells·ml−1). Chi-square tests determined that error is not independent of preprocessing methods: using the filtrate method or unfiltered water, in addition to refining the conversion factor of raw fluorescence to cell size, can decrease the grey area where exceedance of the discharge standard cannot be measured with certainty (at least for the studied populations). When examining in situ ballast water, the BW680 detected significantly fewer viable organisms than microscopy, possibly due to factors such as organism size or ballast water age. Assuming both the BW680 and microscopy with FDA stain were measuring fluorescence and enzymatic activity/membrane integrity correctly, the observed discrepancy between methods may simply reflect that the two methods are measuring different characteristics of life. This is the first study to conduct proof-of-concept testing for a rapid compliance detection tool using freshly collected harbour water concomitantly with in situ ballast water; our results demonstrate that it is important to challenge potential compliance tools with water samples spanning a range of biotic and abiotic conditions.

The comparison of antimicrobial effectiveness of contact lens solutions

The aim of this study was to compare the effects of widely used multipurpose contact lens solutions against Staphylococcus aureus and Pseudomonas aeruginosa, in addition to cystic and trophozoite forms of Acanthamoeba castellanii and A. polyphaga, that cause microbial keratitis. Three multipurpose solutions were tested: SOLO-care, ReNu, and Opti-Free Express. The test solutions were challenged with P. aeruginosa (ATCC 27853) and S. aureus (ATCC 2913) based on the ISO stand-alone and regiment test procedure for disinfecting products, A. polyphaga (ATCC 30871) and A. castellanii (1501/1A) cystic and trophozoite forms. Multipurpose solutions were sampled for surviving microorganisms at manufacturer's minimum recommended disinfection time. The number of viable organisms was determined, and log reductions were calculated. ReNu and SOLO-care resulted in a reduction greater than the required mean 3.0 logarithmic reduction against S. aureus, and SOLO-care and Opti-Free Express resulted in a reduction more than the required mean 3.0 logarithmic reduction against P. aeruginosa. Against the cystic and trophozoite forms of A. castellanii, the log reduction provided by SOLO-care was 1.01 and 1.31 log, respectively. ReNu provided a 0.83 log reduction of the cystic form and a 1.21 log reduction of the trophozoite form. Using Opti-Free Express, the log reduction for both forms was 1.31. SOLO-care led to a 0.61 log reduction of the cystic form of A. polyphaga and a 1.01 log reduction of the trophozoite form. ReNu provided a 0.41 log reduction of the cystic form and a 4.99 log reduction of the trophozoite form. Opti-free Express resulted in a 0.89 log reduction of the cystic form and a 3.11 log reduction of the trophozoite form. Multipurpose contact lens solutions using similar regimens can show different disinfection abilities.

Performance testing of ballast water management systems: Revisiting the interpretation of organisms ≥10 μm and ≤50 μm in minimum dimension

Phytoplankton are a major concern in the introduction of marine invasive species by ships. The current ballast water performance standard (Regulation D2) under the Ballast Water Convention prescribes the number of viable organisms allowed in discharged ballast water. For organisms ≥10 μm and ≤50 μm in minimum dimension, the D2 allows &amp;lt;10 viable organisms per ml, a size category including mostly phytoplankton. However, many phytoplankton are narrower than 10 μm but much longer than 10 μm. This discrepancy causes two major problems: firstly, ballast water management systems will not be examined for their performance at removing organisms larger than regulated by D2. Secondly, this will require higher concentrations of plankton in the challenge water to meet the required test water condition of &amp;gt;103 ml−1 for organisms of sizes as stipulated in the guidelines. Examination of the seasonal distribution of local Korean fresh and sea water shows that phytoplankton communities are frequently dominated by cells &amp;lt;10 μm in width but &amp;gt;10 μm in length. In addition, review of over 600 freshwater diatoms of elongated shapes reveals that more than 300 are &amp;gt;10 μm long, but &amp;lt;10 μm wide. We suggest consideration of these phytoplankton in land-based or shipboard treatment procedures and to report their treatment efficacy, in addition to reporting the performance of ballast water management systems in accordance with the D2 regulation.

Approaches to setting organism‐based ballast water discharge standards

As a vector by which foreign species invade coastal and freshwater waterbodies, ballast water discharge from ships is recognized as a major environmental threat. The International Maritime Organization (IMO) drafted an international treaty establishing ballast water discharge standards based on the number of viable organisms per volume of ballast discharge for different organism size classes. Concerns that the IMO standards are not sufficiently protective have initiated several state and national efforts in the United States to develop more stringent standards. We evaluated seven approaches to establishing discharge standards for the > 50-microm size class: (1) expert opinion/management consensus, (2) zero detectable living organisms, (3) natural invasion rates, (4) reaction-diffusion models, (5) population viability analysis (PVA) models, (6) per capita invasion probabilities (PCIP), and (7) experimental studies. Because of the difficulty in synthesizing scientific knowledge in an unbiased and transparent fashion, we recommend the use of quantitative models instead of expert opinion. The actual organism concentration associated with a "zero detectable organisms" standard is defined by the statistical rigor of its monitoring program; thus it is not clear whether such a standard is as stringent as other standards. For several reasons, the natural invasion rate, reaction-diffusion, and experimental approaches are not considered suitable for generating discharge standards. PVA models can be used to predict the likelihood of establishment of introduced species but are limited by a lack of population vital rates for species characteristic of ballast water discharges. Until such rates become available, PVA models are better suited to evaluate relative efficiency of proposed standards rather than predicting probabilities of invasion. The PCIP approach, which is based on historical invasion rates at a regional scale, appears to circumvent many of the indicated problems, although it may underestimate invasions by asexual and parthenogenic species. Further research is needed to better define propagule dose-responses, densities at which Allee effects occur, approaches to predicting the likelihood of invasion from multi-species introductions, and generation of formal comparisons of approaches using standardized scenarios.

An evaluation of the pharmaceutical quality and antimicrobial effectiveness of some frequently used eye drop products available for sale in Nigeria

Aim: Eye drop products must be properly packaged and must be sterile throughout the period of use. For this reason, we evaluated eye drops offered for sale and used for the treatment of eye diseases in Nigeria for their pharmaceutical quality and antimicrobial effectiveness. Materials and Methods: Eleven different sterile eye-drop product samples containing gentamicin, chloramphenicol, timolol, tropicamide, tetrahydrozoline, pilocarpine, antazoline-tetryzoline, diclofenac, dexamethasone, and flubiprofen were opened and tested for bacterial contamination after exposure to air over 56 days. To assess the possibility of contaminations by pathogens due to repeated handling during use about 10 7 -10 8 cells of Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Candida albicans were added to other newly opened eye drops and incubated at room temperature. Samples were collected and the number of viable organisms was estimated. Eye-drop product samples were also investigated for packaging, pH, and clarity. Results: No viable microorganisms were detected in the eye drops during and at the end of the 56 days exposure to air. All the samples exhibited rapid bactericidal and fungicidal activities at a rate which depended on the species of pathogens and the content of the sample. The anti-infective samples demonstrated the highest rapidity in microbicidal activities. There were no microbial survivors in any of the samples after 4 h of inoculation by pathogens. Conclusions: The study concluded that generally multi-dose eye drop products offered for sale in Nigeria were of acceptable microbial quality and possessed good antimicrobial effectiveness.

IMO 선박평형수 처리장치 기술과 발전 방향에 대한 고찰

Abstract − For smooth implementation of the IMO Ballast Water Management Convention that is to come intoeffect in the near future, IMO and Member States are working on the development of various technologies andestablishment of legislative action. Ballast water treatment systems are essential, yet difficult technologies, asthey need not only to treat living organisms, but also define whether they are viable or not, count the number ofviable organisms, and present quantitative results of the concentration of active substances. Despite the fact thatthe Convention is looming in the near future, the issues mentioned above obstruct the setup of consensual tech-nologies for performance reliability of the treatment system and analysis method of efficacy test results. Thispaper considers the unsolved issues of the ballast water treatment technologies, and presents guidelines to solvethese issues.Keywords: IMO Convention(국제해사기구 협약), Ballast Water(선박평형수), Performance Standard(성능기준), Treatment System(처리장치 ), Type Approval(형식승인), Sampling(샘플링)

Contact lens disinfecting solutions antibacterial efficacy: comparison between clinical isolates and the standard ISO ATCC strains of Pseudomonas aeruginosa and Staphylococcus aureus

To evaluate the disinfectant properties of the three multipurpose contact lens disinfecting solutions available in Iran, against clinical isolates and the standard ISO ATCC strains of Pseudomonas aeruginosa and Staphylococcus aureus, based on the international organization for standardization (ISO) 14729 guidelines. Three multipurpose solutions that were tested were ReNu Multiplus, Solo Care Aqua and All-Clean Soft. The test solutions were challenged with clinical isolates and the standard strains of P. aeruginosa(ATCC 9027) and S. aureus(ATCC 6538), based on the ISO Stand-alone procedure for disinfecting products. Solutions were sampled for surviving microorganisms at manufacturer's minimum recommended disinfection time. The number of viable organisms was determined and log reductions calculated. All of the three test solutions in this study provided a reduction greater than the required mean 3.0 logarithmic reduction against the recommended standard ATCC strains of P. aeruginosa and S. aureus. Antibacterial effectiveness of Solo Care Aqua and All-Clean Soft against clinical isolates of P. aeruginosa and S. aureus were acceptable based on ISO 14729 Stand-alone test. ReNu MultiPlus showed a minimum acceptable efficacy against the clinical isolate of S. aureus, but did not reduce the clinical isolate by the same amount. Although the contact lens disinfecting solutions meet/exceed the ISO 14729 Stand-alone primary acceptance criteria for standard strains of P. aeruginosa and S. aureus, their efficacy may be insufficient against clinical isolates of these organisms.

Determining the viability of marine protists using a combination of vital, fluorescent stains

Determining the viability of protists and small microzooplankton has long been a focus of studies in marine biology and ecology. It is especially relevant in the issue of shipborne invasive species, and impending international guidelines and various national regulations on the allowable concentrations of organisms in discharged ballast water have spurred the growth of an industry that develops and manufactures ballast water management systems. The success of management systems and ability of ships to meet ballast water discharge standards is determined by the number of viable organisms in treated water. Here, we propose combining two vital, fluorescent stains (fluorescein diacetate [FDA] and 5-chloromethylfluorescein diacetate [CMFDA]) with direct microscopic observation to enumerate viable organisms ≥10 and <50 μm in minimum dimension (nominally protists). This approach was validated in four locations in the United States to determine the efficacy of the stains. Although the accuracy of the stains varied by geographic location and the taxonomic composition of the planktonic assemblage, combining fluorescent stains is a robust, powerful tool that can be optimized for the species present at each location. While this method was developed for analyzing viable organisms in treated ballast water, it may also be used or adapted for any field of research that examines a broad taxonomic range of autotrophic and heterotrophic plankton.

Experimental sepsis using Pseudomonas aeruginosa: the significance of multi-drug resistance

In order to clarify whether susceptible and multidrug-resistant Pseudomonas aeruginosa differ in the mechanism of induction of sepsis, three different isolates were used; one susceptible (isolate A) and two (isolates B and C) multidrug-resistant. Isolate B had moderately elevated MICs of antipseudomonal antimicrobials and isolate C highly elevated MICs. Each isolate was infused by a catheter inserted into the right jugular vein of six rabbits. Survival was recorded; blood was sampled at regular time intervals for estimation of bacterial blood counts, malondialdehyde (MDA) and tumour necrosis factor-alpha (TNFα). Quantitative cultures of various organs were performed after death or sacrifice. Mean survival after challenge by isolates A, B and C was 0.73, 2.58 and 11.00 days, respectively ( P of comparisons A versus B, 0.0048; A versus C, 0.0012; B versus C, 0.0005). The number of viable organisms in the blood after challenge using isolates A and B was greater than the viable counts of C. Serum MDA was lower after challenge with B and C compared with A. Serum TNFα levels were higher after challenge by isolate A compared with isolate C. The bacterial loads of the liver, lower right lung lobe, spleen and mesenteric lymph nodes were greater after challenge by isolate A than the other isolates. It is concluded that infection by multidrug-resistant P. aeruginosa is accompanied by increased survival compared with infection by susceptible isolates; that finding might be explained by the different mechanisms leading to sepsis. Further studies must be done to clarify the significance of these observations for therapeutics.

The effect of temperature on bactericidal properties of 10% povidone-iodine solution

Objective: Ten percent povidone-iodine (PVI) is commonly used as a bactericidal solution before amniocentesis is performed. Warming PVI may increase patient comfort; however, the effect of warming on its bactericidal properties is not known. The objective of this study was to determine the effect of warming 10% PVI on its bactericidal properties. Study Design: Room temperature of PVI was 25°C, and temperature in an ultrasonic gel warmer was 32°C. In vitro experiments were conducted in 25°C and 32°C water baths. Nine milliliters of PVI at each temperature was added to 1 mL of bacteria (107 organisms/mL Staphylococcus aureus, Enterococcus species, Escherichia coli, group B Streptococcus). After 0.25, 0.5, 1, 2, 4, and 8 minutes, 1-mL samples were removed and added to 4 mL of 0.5% sodium thiosulfate (to neutralize the iodine and interrupt bactericidal action). The number of viable organisms was determined by plating 0.1-mL samples on trypticase soy agar plates. Plates were incubated at 37°C for 24 hours and colony-forming units (CFUs) were counted. For in vivo experiments in 40 volunteers, a 9-cm2 area of the dorsum of each hand was wiped with a sterile cotton swab to obtain a sample of bacteria for culture. The area was then wiped for 15 seconds with PVI at 25°C or 32°C and recultured. The bactericidal properties of PVI at each temperature were compared. The Mann-Whitney U test was used as appropriate, and P <.05 was considered significant. Results: In vitro, PVI was bactericidal against E coli, S aureus, Enterococcus species, and group B Streptococcus within 0.25 minutes at both 25°C and 32°C, with median bacterial growth of 0 CFU/plate for each species of bacteria studied (3 replicates at each temperature). Median bacterial growth from skin was 4 CFU/plate (range, 0 to >100). After hands were wiped with PVI at 25°C and 32°C, median bacterial growth was 0 CFU/plate (range, 0-8) and 0 CFU/plate (range, 0-15), respectively (not significant). Conclusion: PVI is as effective at 32°C as it is at 25°C. Use of PVI at 32°C should be considered to increase patient comfort in procedures performed without the use of anesthetics. (Am J Obstet Gynecol 2002;186:869-71.)

Measuring Intracellular Mycobacterial Killing Using a Human Whole Blood Assay

Background : The mechanisms through which cellular activation results in intracellular mycobacterial killing is only partially understood. However, in vitro studies of human immunity to Mycobacterium tuberculosis have been largely modeled on the work reported by Crowle, which is complicated by several factors. The whole blood culture is simple and allows the simultaneous analysis of the relationship between bacterial killing and the effect of effector cells and humoral factors. In this study, we attempted to determine the extent to which M. tuberculosis is killed in a human whole blood culture and to explore the role of the host and microbial factor in this process. Methods : The PPD positive subject were compared to the umbilical cord blood and patients with tuberculosis, diabetes and lung cancer. The culture is performed using heparinized whole blood diluted with a culture medium and infected with a low number of M. avium or M. tuberculosis for 4 days by rotating the culture in a , 5% incubator. In some experiments, methlprednisolone- or pentoxifyline were used to inhibit the immune response. To assess the role of the T-cell subsets, CD4+, CD8+ T-cells or both were removed from the blood using magnetic beads. The log killing ratio was defined using a CFU assay as the difference in the log number of viable organisms in the completed culture compared to the inoculum. Results : 1. A trend was noted toward the improved killing of mycobacteria in PPD+ subjects comparing to the umbilical cord blood but there was no specific difference in the patients with tuberculosis, diabetes and lung cancer. 2. Methylprednisolone and pentoxifyline adversely affected the killing in the PPD+ subjects umbilical cord blood and patients with tuberculosis. 3. The deletion of CD4+ or CD8+ T-lymphocytes adversely affected the killing of M. avium and M. tuberculosis by PPD+ subjects. Deletion of both cell types had an additive effect, particularly in M. tuberculosis . 4. A significantly improved mycobacterial killing was noted after chemotherapy in patients with tuberculosis and the logKR continuously decreased in a 3 and 4 days of whole blood culture. Conclusion : The in vitro bactericidal assay by human whole blood culture model was settled using a CFU assay. However, the host immunity to M. tuberculosis was not apparent in the human whole blood culture bactericidal assay, and patients with tuberculosis showed markedly improved bacterial killing after anti-tuberculous chemotherapy compared to before. The simplicity of a whole blood culture facilitates its inclusion in a clinical trial and it may have a potential role as a surrogate marker in a TB vaccine trial.

A combined in vivo pharmacokinetic-in vitro pharmacodynamic approach to simulate target site pharmacodynamics of antibiotics in humans.

We describe a new approach to quantify in vivo anti-infective activity by simulating effect site pharmacokinetics of antibiotics in vitro. This approach is based on (i) the in vivo measurement of interstitial drug pharmacokinetics (PK) at the target site and (ii) a subsequent pharmacodynamic (PD) simulation of the time versus drug concentration profile in an in vitro setting. To demonstrate the feasibility of this approach, individual time-concentration profiles of ciprofloxacin were measured in the interstitial space fluid of eight healthy volunteers by microdialysis following iv administration of 200 mg. Thereafter, different isolates of Pseudomonas aeruginosa were exposed in vitro to the interstitial ciprofloxacin concentration profile obtained from in vivo experiments. This led to a 1- to 3-log10 decrease in the number of viable organisms after 8 h. Significant correlations were observed between the maximal bactericidal effect and several PK surrogate parameters, notably the AUC/MIC ratio (P: = 0.0005), the C:max/MIC ratio (P: = 0.006) and the time > MIC (P: = 0.02). Furthermore, the data were analysed with an integrated PK-PD model allowing a much more detailed evaluation of the data than using MIC. The model employed an E:max relationship to link unbound ciprofloxacin concentration to bacterial kill rate. In conclusion, our experiments show that therapeutic success and failure in antimicrobial therapy may be explained by pharmacokinetic variability at the target site. Therefore, the in vivo PK-in vitro PD approach presented in our study may provide valuable guidance for drug and dose selection of antimicrobial agents.

In vitro studies of the effect of antiseptic-containing mouthwashes on the formation and viability of Streptococcus sanguis biofilms.

The aims of this study were to evaluate the growth of Streptococcus sanguis on hydroxyapatite, bovine enamel and polytetrafluoroethylene substrata in a constant depth film fermentor, and to determine the effects of three antimicrobial-containing mouthwashes on biofilm formation and bacterial viability on hydroxyapatite and enamel. There was little difference in the final cell density (5 x 10(4) cfu mm-2) of the Strep. sanguis biofilm on the three substrata. When hydroxyapatite-grown biofilms were exposed to the mouthwashes for 1 min, the one containing triclosan (T) proved the most effective. The chlorhexidine-containing mouthwash (CX) also achieved significant kills. The T-containing mouthwash was the most effective at killing biofilms grown on enamel. Pre-treatment of hydroxyapatite with CX, cetylpyridium chloride (CPC) or T for 1 min resulted in undetectable biofilm formation after 8 h. After 8 h of growth, only biofilms grown on enamel discs pre-treated with CX showed a reduction in the number of viable organisms. In conclusion, the results of this study have shown that while growth of Strep. sanguis on hydroxyapatite and enamel were similar, the ability of antimicrobial agents to prevent the accumulation of viable bacteria depended on the nature of the substratum.

Biphasic in vivo immune function after low- versus high-dose alcohol consumption

A series of experiments was performed to assess the alterations in immune status in vivo that are associated with differences in the amount and duration of ethanol intake. Using a nonspecific delayed cutaneous hypersensitivity-like response to the intradermal injection of phytohemagglutinin, the area of induration (skin test response) was significantly enhanced ( p = 0.008) after low-dose ethanol (0.5 g/kg) administered daily by gastric gavage for 5 days. High-dose ethanol (6.0 g/kg) significantly diminished this response ( p = 0.03). Using an experimental model of Mycobacterium bovis hepatitis, the host immune response was also altered in a biphasic manner after chronic, 28-day ethanol consumption. With this model 0.43 ± 0.03 g/kg/day (mean ± SEM) of ethanol (low dose) was associated with a 40% improvement in the removal of the organisms from liver tissue ( p = 0.002). High dose (12.1 ± 0.5 g/kg/day) impaired removal, resulting in a 55% increase in the number of viable organisms ( p = 0.001). The levels of three cytokines, MIF, TNF-α, and IL-2, known to be involved in the modulation of the host response to mycobacterial infections, were measured in sera after the infection. The serum levels of these cytokines in response to infection did not correlate with this biphasic response to different alcohol dose levels.

IN VIVO EVALUATION OF TIMING, DEGREE, AND DISTRIBUTION OF BACTERIAL TRANSLOCATION FOLLOWING EXPERIMENTAL SMALL BOWEL TRANSPLANTATION

These studies were designed to evaluate the correlation between morphologic and functional changes after heterotopic auxiliary small bowel isograft with systemic venous drainage and two ostomies in 20 Lewis rats. Morphologic damage of the graft was scored by full-thickness biopsies before surgery and 1, 3, 5, and 7 days after transplant. Functional evaluation of the graft was done, at the same time points, by urinary excretion of lactulose and mannitol injected in the proximal ostomy. The intestinal permeability was also studied by injecting Escherichia coli labeled with indium-111 oxine in the proximal ostomy. Translocation of radiolabeled bacteria was quantitated in extraintestinal tissues by radionuclide counts and number of viable organisms and in vivo by scintigraphic imaging. One day after transplant, significant graft damage (score 17.2 +/- 4.2) was observed when compared with the pretransplant value (7.3 +/- 2.6). The degree of tissue injury was similar on days 3 (15.8 +/- 3.5) and 5 (16.1 +/- 3.9) after transplant and remained high on day 7 (11.8 +/- 2.8). The lactulose to mannitol ratio showed a significantly increased permeability on day 1 (17.5) versus pretransplant values (2.6), remained high on day 3 (8.6), and returned to normal values on day 5 (2.8). Translocation of bacteria to distant organs, as measured by both radionuclide counts and number of viable organisms, was strikingly enhanced on day 1 after transplantation, compared with control animals, but returned to the pretransplant value on day 3. A good qualitative and quantitative correlation was observed between radionuclide counts in the extraintestinal organs and in vivo images obtained by scintigraphic scanning. In conclusion, in this model, timing and degree of bacterial translocation do not seem to correlate well, with the exception of the acute post-transplantation phase, with morphologic and permeability changes of the graft. Evaluation of translocation by scintigraphic imaging appears a suitable approach to study in vivo the kinetics and distribution of this process.

A comparison of the efficacy of four units for the physical disinfection of contact lenses

Four contact lens disinfection units were challenged with saline suspensions of Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, Escherichia coli and a clinical isolate of Candida albicans. The disinfection units all relied on physical disinfection methods and included the Sonasept unit which uses ultrasound and heat, the Aquasteril unit which uses ultraviolet radiation, the Bausch and Lomb Heat unit and the OPSM Thermos flask, both of which act through moist heat. Both the Sonasept and Aquasteril units performed poorly under most circumstances, causing little reduction in the number of viable organisms and in some cases there was an increase in the number of viable organisms following a disinfection cycle. The Bausch and Lomb Heat unit and the OPSM Thermos flask killed the challenge organisms under all test conditions.

An alginate bead technique for determining the safety of microwave cooking

A simple method for determining the microbiological safety of microwave cooking is described. It involves the use of a micro‐organism with known heat sensitivity immobilized in alginate beads which can be placed throughout a food prior to microwaving. The reduction in numbers of viable organisms is related not only to the temperature the bead has been exposed to but also to the duration of heating. The method is capable of achieving multi‐point measurements of the effects of lethal temperatures during microwave cooking.

Relationships between PGL-1 antigen in serum, tissue and viability ofMycobacterium lepraeas determined by mouse footpad assay in multibacillary patients during short-term clinical trial

In connection with a 56-day controlled clinical trial for comparing the therapeutic effects between pefloxacin and ofloxacin in 21 lepromatous patients, we have studied the relationships between PGL-1 antigen level in serum and in skin and serum PGL-1 antibody titre on the one hand, and the viability of Mycobacterium leprae, as measured by serial mouse footpad inoculations, and other bactericidal parameters on the other. Before and during treatment, significant correlation was found between serum PGL-1 level and the morphological index (MI), and with the number of viable organisms per mg skin tissue. However, neither serum PGL-1 antibody titre nor skin PGL-1 antigen level showed significant change during the 56-day trial. Because the reduction of serum PGL-1 level was well correlated but less pronounced as compared with the evolution of viable organisms during treatment, the serum PGL-1 antigen assay may be useful as an early indicator of response to chemotherapy in short-term clinical trial, but it is unlikely to replace mouse footpad inoculation for the evaluation of viability of M. leprae.