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At least 19 recordsLinked to original sources
PubMed1996

A semi-empirical precision control criterion for duplicate microbial colony counts.

A simple precision criterion (Z) of the logarithmic range (R) of duplicate microbiological determinations was developed. It is based on a freely selected relative technical uncertainty and the observed mean colony count. The model takes into account the different character of the technical and distribution uncertainty. The ensuing non-linear control criterion avoids the unrealistic assumptions of constancy that the pure Poisson and 'black box' (APHA) models make. The standardized variable Q = R/sigma R provides a linear control chart limit that enables sequential (temporal) plotting of the data.

Colony Count, Microbial↗
PubMed1970

Automated counting of microbial colonies.

The time required for direct counting of colonies on agar plates for estimating population density of viable microorganisms has precluded studies requiring measurement of such a parameter. Bowman, Blume, and Vurek have described a photo-electrical capillary tube scanner which automates the counting. Results obtained with an instrument similar to that of Bowman et al. have been intensively analyzed with respect to precision and accuracy. The sources of "errors" have been ascertained, and the instrument's potentialities and limitations are discussed.

Automation↗
PubMed1999

Disinfection of denture base acrylic resin.

STATEMENT OF PROBLEM: During repair or adjustments of acrylic resin removable complete and partial dentures, particles of the acrylic resin from the interior of the prosthesis may expose dental personnel to microbial health hazards if the prosthesis has not been thoroughly disinfected. PURPOSE: This study investigates the efficacy of a commercially prepared microbial disinfectant (Alcide) on the external and internal surfaces of acrylic resins. MATERIAL AND METHODS: Four groups of acrylic resin were incubated in an experimental model to simulate the oral environment over time. Specimens were treated in 2 groups, disinfected and not disinfected, and then further grouped by breaking and not breaking. Analysis was performed with microbial colony counts, SEM, and statistical analyses. RESULTS: Viable microorganisms still remain on the internal and external surfaces of treated resins. CONCLUSION: Chlorine dioxide reduces, but does not eliminate, viable microorganisms on these dental prostheses.

Acrylic Resins↗
PubMed2004

Elimination of intraluminal colonization by antibiotic lock in catheters.

Antibiotic lock (AL) technique for catheter related infection encompasses the filling of a catheter lumen with high concentrations of antibiotics for hours. The goal of AL therapy is to decontaminate the intraluminal surface of the catheter. However the duration of antibiotic therapy is not established. An in vitro model was designed to establish the time needed to eliminate intraluminal microbial colonization and to evaluate the efficacy of vancomycin in comparison with teicoplanin by using laboratory AL model. Human plasma was instilled into the catheters to allow deposition of fibrin and other products on the catheter wall. After 48 hours, the catheters were drained and inoculated with bacteria in tryptic soy broth. The catheters were then drained and filled with either (a) vancomycin saline solution (VSS) lock (b) teicoplanin saline solution (TSS) lock or (c) saline solution (SS) as the control and then incubated for 12 hours. After 12 hours incubation all the catheter were drained and filled with human plasma. Instillation of human plasma and AL was alternated every 12 hours to simulate clinical conditions. For each day three catheters, locked with VSS, TSS and SS were cultured for colony count. Microbial counts were expressed as total colony-forming units per longitudinal centimeters of catheter surface. A significant decrease in intraluminal catheter colonization started as early as day 1. At the end of 7th day catheters treated with VSS and TSS lock were completely sterile. The decrease of intraluminal colonization was similar in catheters treated with VSS and TSS lock. Also the decrease of intraluminal colonization were similar in catheter colonized with slime forming S. epidermidis and nonslime-forming S. epidermidis.

Anti-Bacterial Agents↗
PubMed1991

Evaluation of surgical scrub and antiseptic solutions for surgical preparation of canine paws.

The purpose of the prospective study reported here was to evaluate surgical preparation of canine paws. Three combinations of surgical scrub solutions and antiseptic solutions were used: (1) 7.5% povidone-iodine scrub/10% povidone-iodine solution; (2) 2% chlorhexidine acetate scrub/2% chlorhexidine diacetate solution; and (3) tincture of green soap/70% isopropyl alcohol. The control was warm (38 to 42 C) tap water. Four microbial colony counts were used to evaluate surgical preparation of 4 paws of 8 dogs. Specimens were obtained from the paws for a baseline microbial flora count. After surgical scrub was performed, additional specimens were obtained for bacteriologic culturing. Antiseptic was applied followed by collection of another specimen for bacteriologic culturing. A final specimen was obtained following a 24-hour period under a sterile occlusive bandage. The 3 scrub solutions and the tap water control resulted in lower colony counts following scrubbing of the paws; however, only the 3 antiseptic solutions resulted in further colony count reduction after their application. Evaluation of residual colony counts isolated from specimens taken after a 24-hour period under a sterile occlusive bandage revealed chlorhexidine and povidone-iodine scrub/antiseptic combinations to be similar in antibacterial activity, with significantly (P less than or equal to 0.05) lower colony counts than those from specimens of paws treated with either the tincture of green soap/isopropyl alcohol combination or the tap water control. The lack of a significant difference between the bacterial counts immediately after surgical preparation with povidone-iodine and chlorhexidine and their respective 24-hour residual counts, indicated no particular advantage to surgical preparation and occlusive bandaging 24 hours prior to surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Impact of the nematophagous fungus Pochonia chlamydosporia on nematode and microbial populations.

The microbial and nematode populations associated with two plants (tomato and cabbage) inoculated with the nematophagous fungus, Pochonia chlamydosporia var. chlamydosporia or root knot nematode (Meloidogyne incognita), or both, were compared with those in unplanted controls. The dominant factor affecting culturable microbial populations was found to be the presence or absence of tomato plants. Generally microbial colony counts were lowest in unplanted soil, small increases were associated with cabbage and significantly greater numbers with tomato plants. Differences in microbial diversity (estimated from community profiles of carbon substrate utlisation, using Biolog) were observed between planted and unplanted soils, however, there were few differences between soils with either of the two plants. The presence of P. chlamydosporia was associated with a reduction in the numbers of plant parasitic nematodes (51%-78%) including the migratory ectoparasites, whereas free-living nematodes, culturable bacteria and bacterial populations assessed by Biolog were unaffected by the application of fungus.

Animals↗
PubMed1994

Comparison of respiratory activity and culturability during monochloramine disinfection of binary population biofilms.

Biofilm bacteria challenged with monochloramine retained significant respiratory activity, even though they could not be cultured on agar plates. Microbial colony counts on agar media declined by approximately 99.9% after 1 h of disinfection, whereas the number of bacteria stained by a fluorescent redox dye experienced a 93% reduction. Integrated measures of biofilm respiratory activity, including net oxygen and glucose utilization rates, showed only a 10 to 15% reduction. In this biofilm system, measures of microbial respiratory activity and culturability yielded widely differing estimates of biocide efficacy.

Chloramines↗
PubMed1993

Effect of time, temperature and humidity on biodeterioration of corn cake snack.

Food spoilage microorganisms representing 5, 6 and 10 genera of moulds, yeasts and bacteria, respectively were isolated from corn cake snack. Each of the samples analysed had initial pH value favourable to microbial growth and activities while only 28% had spoilage-enhancing moisture contents (> 13%). The effect of temperature and relative humidity (RH) on biodeterioration during a 24-day storage period was determined by monitoring changes in the pH and total microbial colony counts. Whereas very little or no deterioration was recorded for samples contained in 51% and 71% RH chambers at 30 and 45 degrees C, substantial deterioration was obtained at the same temperatures under 89.5% and 100% RH. At 15 degrees C, very little or no deterioration was detected except under 79.5%, 89.5% and 100% RH when slight spoilage changes were recorded as from the 12th or 18th day. The overall results show that the obtained colony counts and pH values monitor spoilage equally.

Bacteria↗
PubMed1997

Influence of dietary levels of fat, fiber, and copper sulfate and fat rancidity on cecal activity in the growing turkey.

Two experiments were conducted with 6- to 10-wk-old turkeys. In Experiment 1, 6-wk-old turkeys were fed diets varying in level of fat (4.4 to 10%) or fiber (2.5 to 9.0%). The diets also contained extra copper as copper sulfate at either 0.1 or 0.2% of the diet. At 8 wk of age, 15 replicate birds were housed in individual cages and all excreta was collected. Excreta was separated as being "regular" or "cecal" in origin based on appearance. At 10 wk of age, 10 birds per treatment were killed and cecal contents removed under anaerobic conditions. Cecal contents were assayed for various nutrients and viscosity was measured. In a second comparable study, turkeys were fed animal-vegetable fat or regular or rancid canola oil (60.25 vs 120.24 ng/g malonaldehyde, respectively). In Experiment 1, feeding copper sulfate had the most noticeable effect on various cecal parameters. There was an increase (P < 0.01) in dry matter cecal droppings produced and the cecal contents were of increased viscosity (P < 0.05). Copper had no effect on pH or microbial colony count of the cecal contents. Feeding copper resulted in a significant increase in the high molecular weight (> 300,000) fraction of cecal contents and this fraction was of higher viscosity. Feeding copper sulfate resulted in a dramatic increase in copper content of cecal contents (280 to 11,848 ppm), although the copper content of regular excreta was also increased (17 to 1,008 ppm). The various levels of fiber and fat generally had no effect on cecal parameters. Feeding rancid canola oil did result in increased viscosity of cecal contents, compared to the situation seen with fresh canola oil. Fat rancidity per se, however, failed to influence other parameters such as total mass of cecal material produced and composition of cecal material. Feeding copper sulfate or rancid fat will increase the viscosity of cecal material, which may contribute to litter management problems.

Animals↗
PubMed1983

[Microbiological studies of PVC packing sheets and sediments from a wet cooling tower].

On surface of PVC packing sheets in wet cooling towers thick sediment layers can often be observed (Fig. 1) which usually cause several technological troubles. Microbiological investigations were made in order to estimate whether some hygienic risk possibly based on the proliferation of hygienic relevant microorganisms in the sediment have to be considered. An abundance of bacteria actinomycetes and fungi was found in the sediments from PVC packing sheets which were exposed for 6 or 20 weeks in a wet cooling tower (Table 2). However, the microbial (colony) counts usually decreased when the exposition time increased. Pseudomonas aeruginosa was not detected at all. Coliform bacteria and Escherichia coli showed a declining development both in the sediment and in the cooling water unter test (Table 3). Total volume of plankton also decreased in cooling water incubated with small pieces of PVC packing sheets. The results indicate the sediment formation on PVC packing sheets in wet cooling towers probably not to be problem of environmental hygiene but technology. The sediment formation seems to depend mainly of the quality (i.e. pollution degree) of cooling water and also of surface properties of the packing sheets.

Actinomycetales↗
PubMedDate not supplied

A comparison of the MicroCount Digital System to plate count and membrane filtration methods for the enumeration of microorganisms in water for pharmaceutical purposes.

The enumeration of microorganisms in water for pharmaceutical purposes using the MicroCount Digital System (Millipore Corporation, Bedford, MA) was compared to the USP-recommended Pour Plate and Membrane Filtration Count methods. A study, using a pure culture of Buckholderia cepacia, ATCC#25416, showed that the accuracy, precision, reproducibility and linearity of the MicroCount ATP Bioluminescence System was equivalent to or better than the traditional methods. When the MicroCount System was used to monitor purified water and water for injection taps in a pharmaceutical plant over a month, comparable counts to the traditional methods were obtained within 24 hours compared to 48 to 72 hours with the other methods. The effectiveness of the memory device used for the isolation of colonies for characterization was demonstrated by comparing the number and pattern of the positive wells in the MicroCount plates with the isolation of colonies on the microbial count agar plates. The recovery on agar plates, although slightly higher, was not statistically different to the MicroCount plates. The predominated microorganisms isolated using all three methods were Ralstonia pickettii, Bacillus sphaericus, Stenotrophomonas maltophia, and a Staphylococcus species.

Colony Count, Microbial↗
PubMed1990

Therapeutic efficacy of granulocyte colony-stimulating factor alone and in combination with antibiotics against Pseudomonas aeruginosa infections in mice.

The therapeutic efficacy of granulocyte colony-stimulating factor (G-CSF) against an experimental intramuscular infection induced by Pseudomonas aeruginosa in mice was confirmed. Bacterial growth in the infected thigh muscle was suppressed by G-CSF treatment. The change in the number of peripheral blood polymorphonuclear leukocytes (PMN) after bacterial challenge was investigated. The results showed that G-CSF could stimulate stronger defense mechanisms after stimulation by bacterial challenge. In the G-CSF-treated group, more clusters of matured PMN were observed in the infected thigh muscle 6 h after bacterial challenge. Next, the correlation between the number of PMN in the blood at the time of infection and the therapeutic efficacy of antibiotics was investigated. The therapeutic efficacy of ceftazidime, a beta-lactam antibiotic, was affected by the number of blood PMN at the time of infection. In particular, a decrease of peripheral blood PMN at the time of infection resulted in a dramatic decrease in the efficacy of ceftazidime. The reduction in leukopenia by G-CSF remarkably strengthened the therapeutic effect of antibiotics in mice.

Animals↗
PubMed1998

[Value of aspiration of tracheal secretions and bronchoalveolar lavage in diagnosis of nosocomial pneumonia in ventilated patients].

The diagnostic value of endotracheal aspirates with quantitative assessment and bronchoalveolar lavage (BAL) was investigated in 104 mechanically ventilated patients in an anaesthesiologic/surgical intensive care unit. Patients were either considered as "pneumonia positive" (77 patients) according to clinical, radiological or laboratory criteria or "pneumonia negative" (27 patients). Using a threshold of 10(5) colony forming units (cfu) per ml for endotracheal aspirates and 10(4) cfu/ml for BAL-fluid, the results were similar for both techniques (sensitivity 74% and 77% respectively; specifity 63%). In our investigation, in 80% of the cases microbial growth was observed in either both or neither of the techniques. Therefore 20% of the patients had positive results in only one of the two diagnostic procedures. As a consequence of the presented study, quantitative assessment of endotracheal aspirates as a cost-effective, low-invasive and simple technique could be helpful in diagnosing nosocomial pneumonia in mechanically ventilated patients. Performance of BAL is indicated in patients with clinical signs of nosocomial pneumonia and negative results in endotracheal aspirates (< 10(5) cfu/ml). Nevertheless, diagnostic uncertainty will remain in about 15% of all cases, even when both techniques are applied. The primary use of invasive bronchoscopic techniques, such as BAL, in diagnosis of nosocomial pneumonia has to be considered critically.

Bronchoalveolar Lavage Fluid↗
PubMedDate not supplied

The effect of H2-receptor antagonist and proton pump inhibitor on microbial proliferation in the stomach.

BACKGROUND/AIMS: Intra-gastric bacterial proliferation is frequent in patients with hypochlohydria. However, status of gastric bacterial infection in patients receiving proton pump inhibitor or H2-receptor antagonist remains controversial. The purpose of this study was to investigate the microbial condition of the stomach in patients who received H2-receptor antagonist or proton pump inhibitor. METHODOLOGY: Between November 2000 and January 2002, 102 patients were enrolled in this study. Of these, 52 did not receive any treatment (group I), 26 received H2-receptor antagonist (group II), and 24 received proton pump inhibitor (group III). Ten mL of gastric juice were aspirated for culture during endoscopic examination. The aerobic and anaerobic bacterial and fungal cultures were performed immediately. A glass pH meter measured the pH of the gastric juice. RESULTS: The intra-gastric pH was 2.91+/-2.06 (mean +/- SD), 4.12+/-2.83, and 5.11+/-2.47 for groups I, II, and III, respectively (p=0.001 between groups I and III, p>0.05 between groups I and II, and groups II and III). The positive bacterial culture rates were 66.7% (16/24) in group III, 46.2% (12/26) in group II, and 28.8% (15/52) in group I (p=0.007 between groups III and I,p>0.05 between groups I and II, and groups II and III). The positive candidal culture rates were 12.5% (3/24) in group III, 11.5% (3/26) in group II, and 17.3% (9/52) in group I (p>0.05). CONCLUSIONS: Patients who received proton pump inhibitor had more acid suppression and intra-gastric bacterial infection than those of the control group. The intra-gastric candidal infection was not related to intra-gastric pH or anti-secretory medication in this study.

Adult↗
PubMed1989

Macrophage function in murine allogeneic bone marrow radiation chimeras in the early phase after transplantation.

We tested several of the functions of macrophages (M phi) in the early phase after allogeneic bone marrow transfer to get information about this important aspect of the nonspecific immune system in the T-cell-deficient recipient. On days 3-5 after transfer, the number of M phi was reduced in the spleen, liver, lungs, and peritoneal cavity (Pe). The phagocytosis of sheep red blood cells (SRBC) by these M phi was normal or even enhanced, as in the case of Pe-M phi. Already on days 8-12 after transfer, the number of M phi in spleen and liver exceeded that of controls, whereas the number was still reduced in lungs and Pe. We examined their ability to kill P815 tumor cells, to produce tumor necrosis factor-alpha (TNF alpha), to phagocytose SRBC, to produce reactive oxygen intermediates (ROI) in vitro and to kill Listeria monocytogenes in vivo. Most functions were normal and often even enhanced, depending on the organ origin, but the ability of Pe-M phi to produce ROI was reduced. Proliferative response to macrophage colony-stimulating factor (M-CSF) and killing of YAC-1 tumor cells revealed a high frequency of macrophage precursor cells in the spleen and liver and a high natural killer (NK) activity in the liver. Altogether, enhanced nonspecific immune function, especially preactivated M phi, may enable chimeras to survive attacks by opportunistic pathogens.

Animals↗