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PubMed2003

Each lumen is a potential source of central venous catheter-related bloodstream infection.

OBJECTIVE: To determine the relative rates of microbial colonization of individual lumens in triple-lumen central venous catheters (CVCs) and calculate the chance of detecting catheter-related blood stream infection (CRBSI) if only one lumen is sampled. DESIGN: Prospective evaluation of CVCs from suspected and nonsuspected CRBSI cases. SETTING: University teaching hospital. PATIENTS: Triple-lumen CVCs from 50 cases of suspected CRBSI (a raised peripheral white blood cell count, temperature >37 degrees C, and/or local signs of infection at the catheter skin entry site) were evaluated. For comparison, 50 triple-lumen CVCs routinely removed at the end of use were evaluated. MEASUREMENTS: In both groups, peripheral blood cultures were taken before CVC removal. After CVC removal, each lumen was sampled in vitro using the endoluminal brush, and the tip was then cultured using the Maki roll technique. MAIN RESULTS: CVCs causing CRBSI had significant microbial colonization in one, two, or three lumens in ten (40%), ten (40%), or five (20%) cases, respectively. Overall, random sampling of only one lumen in CVCs causing CRBSI had a 60% chance of detecting significant colonization. CONCLUSIONS: If only one CVC lumen is sampled, a negative result does not reliably rule out infection. Each lumen of multiple-lumen CVCs should be considered as a potential source of CRBSI.

Aged↗

PubMedDate not supplied

The effect of a disinfectant/coolant irrigant on microbes isolated from dental unit water lines.

The purpose of this study was to assess water samples from a hospital dental clinic to determine whether a disinfectant/coolant irrigant containing chlorhexidine (Lines, Micrylium Laboratories) affects the presence of microbial organisms in dental unit waterlines. Water samples from three hospital dental operatories were collected at baseline and after overnight treatment with a disinfectant-containing irrigant followed by sterile water irrigation. Saliva of treated patients and sterile water rinse specimens were collected from the waterlines of these operatories for three consecutive days, then weekly for eight weeks after treatment. Specimens were cultured to identify total heterotrophic plate counts as well as presence of Pseudomonas aeruginosa and Candida species. Baseline organism counts varied from 10(3) to 10(5) colony-forming units per milliliter. After treatment, no organisms were detected in waterline discharge. Decontamination of dental unit waterlines is possible using a disinfectant/irrigant followed by sterile water irrigation. The potential for contamination of the lines from patients' saliva may have been reduced due to use of anti-retraction valves and the disinfectant/sterile water irrigation, as conducted in this study.

Bacteria↗

PubMed1991

Adherence of Pseudomonas aeruginosa to rigid gas-permeable contact lenses.

We examined the adherence of a human corneal isolate of Pseudomonas aeruginosa to unused rigid gas-permeable and hydrogel contact lenses. Adherence to rigid gas-permeable lenses was greater than the adherence to hydrogels. The lower incidence of microbial keratitis associated with rigid gas-permeable lenses, as compared with hydrogel lenses, may be attributed to the more rigorous cleaning and disinfection possible for rigid gas-permeable lenses and/or patient noncompliance with complicated disinfection systems used with hydrogel lenses.

Bacterial Adhesion↗

PubMed2004

Variation of microbiological and biochemical parameters in the faeces of two healthy people over a 15 day period.

BACKGROUND: Recent years have seen increasing interest in the complex microbial ecosystem of the human gastrointestinal tract. Knowledge of its microbial colonists and their beneficial/detrimental activities is important. However, generalized assumptions about the microbial composition of the human gut should be taken with caution until more studies in different human communities have been conducted. The capacity of modulating or inhibiting harmful populations through high doses of beneficial microorganisms (probiotics) is now an attractive possibility. AIMS: The aim of this study was to determine the daily variation in the most prominent and representative of the cultivable microbial populations in the faeces of two healthy Spanish persons, with special reference to the lactic acid bacteria (lactobacilli and bifidobacteria). Faecal enzymatic activities caused or modulated by gut microorganisms were also examined. METHODS: Microbial populations were enumerated in selective and differential media. LAB species isolated from MRS agar plates were further identified by phenotypic and genetic techniques. Enzymatic activities were measured by the semi quantitative method of the API ZYM system. RESULTS: Obligate anaerobes (members of the Clostridium clusters and species of bacteroides and bifidobacteria) made up the largest bacterial populations in both individuals (ranging between 10(10)-10(11) cfu/g of faeces) and remained constant over time. Lactobacilli species were found at an intermediate level (around 10(8) cfu/g), and yeasts and moulds, staphylococci, enterococci, coliforms and Enterobacteriaceae at a lower level (between 10(3) to 10(6) cfu/g). 38 lactic acid bacteria strains identified belonged to Bifidobacterium bifidum [19], Bifidobacterium longum [7], Bifidobacterium adolescentis [7] and Lactobacillus ruminis [5] species. Enzymatic profiles and values were shown to be personal and stable, but inter-sample fluctuations were recorded. CONCLUSIONS: The dominant microbial populations in the faeces of the two persons were similar and stable during the sampling period. Large differences were found in the lactic acid bacterial composition of each individual. Biochemistry seemed to be also personal and stable over time.

Bacteria↗

PubMed1988

Comparison of acridine orange and Gram stains in bacterial keratitis.

We assessed the comparative sensitivities of acridine orange and Gram stains in the examination of corneal scrapings using an experimental model of Pseudomonas aeruginosa keratitis. Acridine orange was more sensitive than Gram stain, requiring concentrations of about 10(4) colony-forming units/mg of corneal tissue compared to approximately 10(5) colony-forming units/mg. Our clinical experience with 21 consecutive cases of suspected microbial keratitis showed a similar diagnostic accuracy of acridine orange and Gram stain. Acridine orange accurately predicted culture results in 15 of 21 specimens (71%) compared to a diagnostic accuracy of 62% (13 of 21 specimens) for Gram stain.

Acridine Orange↗

PubMed2006

Defined multi-species semi-liquid ready-to-use sourdough starter.

This paper aimed at setting up a protocol for the manufacture of a defined multi-species semi-liquid ready-to-use sourdough starter consisting of lactic acid bacteria (LAB) selected on the basis of their capacity of rapid acidification and adaptation to several technological factors. Preliminarily, 56 strains of sourdough LAB were screened based on the acidification kinetics during sourdough fermentation. The influence of temperature (25-37 degrees C), NaCl (2%, w/w, of wheat flour), initial cell number (10(7)-10(9) cfu g(-1)), dough yield (150-180), substrate for cell cultivation (mMRS or SDB media) and phase of cell growth (exponential or stationary phases) on the kinetics of acidification was also determined. Lactobacillus casei DPPMA27, Weissella confusa DPPMA20 and Lactobacillus fructivorans DPPMA8 were selected and used to produce a defined multi-species semi-liquid sourdough starter. Fermentation was carried out in a 2l batch fermentation bioreactor (12 h at 37 degrees C), under controlled pH, by cultivating cells in a medium made of water (60%), flour and other nutrients (40%). The semi-liquid sourdough starter was stored for 30 days under different conditions and used for dough fermentation (dough yield 160). The microbial composition, acidifying activity and fermentation end-products were kept constant during 21 days of storage. The findings of this study may be useful to increase the use of sourdough in bakery industries.

Bioreactors↗

PubMed2006

Locating Escherichia coli contamination in a rural South Carolina watershed.

One of the problems associated with the use of ambient water quality standards in surface water regulation is the difficulty of identifying and regulating nonpoint source pollution, making such standards unenforceable, especially at the local level. We used the Escherichia coli indicator to locate the most contaminated reaches in rural South Carolina's Bush River watershed (297 km(2), 186 stream-km). We divided the watershed into 20 smaller reaches and sampled each reach multiple times, but restricted each sampling round to one day. We located four low order creek reaches, representing just nine stream-km, where we observed geometric mean E. coli densities of over 1250 E. coli/100 mL; in each case, the source of the contamination (riparian grazing of cattle) was easily identifiable. On the Bush River itself, we observed a step change in one reach where geometric means increased from 106 E. coli/100 mL to 565 E. coli/100 mL over the reach's 10 km length. In this case, the sources of contamination were not as obvious as in the lower order streams; in this case, more advanced Microbial Source Tracking techniques will be required to identify the sources. Nevertheless, this sampling protocol helped locate polluted reaches and provided decision-makers with reasonable justifications for concrete action in deciding where (or where not) to install conservation practices and where more sophisticated (and expensive) MST techniques were warranted.

Colony Count, Microbial↗

PubMed1999

Comparison of two kinds of Biolog microplates (GN and ECO) in their ability to distinguish among aquatic microbial communities.

We compared the abilities of Biolog's GN and ECO plates to distinguish among aerobic and heterotrophic bacterial communities in samples from six aquatic environments. The Biolog system is based on interpreting patterns of sole-carbon substrate utilization indicated by color development in a 96-well microtiter plate. Whether of fresh or saltwater origin, bacterial communities utilized > 95% of substrates in both types of plates. Samples from any one environment exhibited similar time courses of average well color development (AWCD) in both GN and ECO plates. Principal component analysis was performed on data sets resulting from combinations of algorithms (AWCD and curve-integration methods) and levels of color development (end-point and set-point approaches). In all cases, the two types of plates demonstrated an equal capacity to discriminate among the heterotrophic expressions of the six microbial communities. Substantial deviation from an anticipated 1:1 correspondence occurred when color development of 25 substrates common to both types of plates was compared. The discrepancies likely are related to the different formulations of low-nutrient media in GN and ECO plates.

Bacterial Typing Techniques↗

PubMed2003

Antimicrobial activity of a new intact skin antisepsis formulation.

UNLABELLED: Different antiseptic formulations have shown limitations when applied to disinfecting intact skin, notably short-term tolerability and/or efficacy. The purpose of this study was optimizing a new antiseptic formulation specifically targeted at intact skin disinfection and evaluating its in vitro microbicidal activity and in vivo efficacy. METHODS: The biocidal properties of the antiseptic solution containing 0.5% chloramine-T diluted in 50% isopropyl alcohol (Cloral; Eurospital SpA Trieste, Italy) were measured in vitro versus gram-positive-, gram-negative-, and acid-alcohol-resistant germs and fungi with standard suspension tests in the presence of fetal bovine serum. Virus-inhibiting activity was evaluated in vitro against human cytomegalovirus, herpes simplex virus, poliovirus, hepatitis B virus, and hepatitis C virus. Tests used different methods for the different biologic and in vitro replication capacity of these human viruses. Lastly, Cloral tolerability and skin colonization retardation efficacy after disinfection were studied in vivo. RESULTS: The antiseptic under review showed fast and sustained antimicrobial activity. The efficacy of Cloral against clinically important bacterial and viral pathogens and fungi was highlighted under the experimental conditions described in this article. Finally, microbial regrowth lag and no side effects were documented in vivo after disinfection of 11 volunteers. CONCLUSIONS: A stable chloramine-T solution in isopropyl alcohol may be suggested for intact skin antisepsis.

2-Propanol↗

PubMedDate not supplied

Microbial contamination of haemodialysis catheter connections.

Bacterial contamination and colonisation of the haemodialysis catheter is a reason for infection in dialysis patients. One reason for contamination may be frequent routine connections at the beginning, during and end of dialysis. Higher infection rates observed with double lumen catheters may be due to the absence of the sterile, disposable device that is fitted between the blood tubing and the catheter hubs with single lumen catheters. A sterile, disposable extension was implemented at the author's unit for use in dialysis with double lumen catheters. The proximal and distal ends of the extension were assessed for microbial contamination after standard dialysis. Results show microbial contamination in almost 30% of the samples retrieved from the extensions. Experiences in PD and the behaviour of skin bacteria on polymers, suggest that disposable extensions might have the potential to serve as a barrier or absorber for bacterial contamination.

Asepsis↗

PubMed2006

Antimicrobial effectiveness of lysozyme immobilized on polyvinylalcohol-based film against Alicyclobacillus acidoterrestris.

In this study, the effectiveness of an active polyvinylalcohol-based film against Alicyclobacillus acidoterrestris was assessed. The active film was fabricated by immobilizing an active compound on the surface of a polymeric matrix and then tested by putting the film in contact with a medium that had been inoculated with microbial cells. Microbiological tests showed that the film was antimicrobial against both a single strain and a culture cocktail of A. acidoterrestris, at 44 degrees C. By monitoring the viable cell concentration under three different packaging conditions, it was possible to demonstrate that the active film was equally effective against both the single strain and the culture cocktail and that it maintained this efficacy at various medium volumes. The same microbial tests were also conducted on viable spores of the investigated microorganism, inoculated both into a laboratory medium and apple juice. The results indicate that these viable spores were better inhibited than cells by the active film in both investigated media.

Anti-Infective Agents↗

PubMed1993

Routine anaerobic bacterial culture and systemic antibiotic usage in the treatment of adult periodontitis: a 6-year longitudinal study.

This investigation evaluated the efficacy of obtaining baseline culture and sensitivity data on a routine basis from the patient with adult periodontitis. Patients diagnosed with chronic adult periodontitis, rapidly progressive periodontitis, or refractory periodontitis were followed for up to 6 years. More than 95% of patients with chronic adult periodontitis were successfully treated with mechanical therapy alone. Approximately one half of the patients with rapidly progressive periodontitis were treated successfully without antibiotics. All of the patients with refractory periodontitis required systemic antibiotics as part of treatment. Most patients with chronic adult periodontitis exhibited one or two species of organisms at baseline, and these organisms were eliminated or reduced to low levels by mechanical therapy. In contrast, patients with rapidly progressive or refractory periodontitis consistently demonstrated multiple species and required systemic antibiotics in conjunction with mechanical therapy to alter the subgingival microbial milieu. Routine culturing and antibiotic therapy is contraindicated in patients with chronic adult periodontitis, but may be beneficial for successful treatment of patients with rapidly progressive or refractory periodontitis.

Adult↗

PubMed1999

A comparison of different culture media for the membrane filter quantification of Aeromonas in water.

A comparative assessment of culture media for the membrane filter enumeration of Aeromonas spp. in water was performed, testing the effects of different incubation conditions (aerobic and anaerobic), temperatures (30 and 37 degrees C) and times (24 and 48 h). Different water samples seeded with test suspensions of Aeromonas spp., fecal material or raw sewage were examined. Results indicate clearly that plates should be incubated aerobically at 30 degrees C for 24 h. If the bacterial contamination is likely to be low, the use of most sensitive culture media, such as SAA, mA, ADA or PADE Agar, is recommended. By contrast, samples with an expected high level of background microbial flora should be analysed through more selective media, such as MIX Agar. However, the low selectivity of all media tested and the high likelihood of false negatives based upon the macroscopic examination of colonies means that further research directed to the development of more efficient media is needed.

Aerobiosis↗

PubMed2005

Using Dirichlet tessellation to help estimate microbial biomass concentrations.

Dirichlet tessellation was applied to estimate microbial concentrations from microscope well slides. The use of microscopy/Dirichlet tessellation to quantify biomass was illustrated with two species of morphologically distinct cyanobacteria (Microcystis aeruginosa and Anabaena flos aquae), and validated empirically by comparison with chlorophyll a and Coulter count analyses. Biomass estimates obtained by microscopy/Dirichlet tessellation were significantly correlated with the results obtained from chlorophyll a and Coulter analyses.

Algorithms↗

PubMed2006

Fluorescence microscopy for studying the viability of micro-organisms in natural whey starters.

AIMS: The aim of this work was to study the viability and cultivability of microbial populations of different natural whey starters and to evaluate their resistance to thermal treatments (such as exposure to high or low temperatures). METHODS AND RESULTS: Twenty-three natural whey starters for Grana Padano cheese were investigated and subsequently pH measurement, plate count agar using Man-Rogasa-Sharpe (MRS) pH 5.4 agar and whey agar medium (WAM) were performed using these samples. LIVE/DEAD BacLight bacterial viability kit was used. Total count and viability of all the 23 samples were high and similar to each other (CV 20%). However, the cultivable population was lower in terms of cfu ml(-1) and number of cells per millilitre than the viable fraction and highly variable, although its count value was higher in WAM than in MRS pH 5.4. The heating (60 degrees C for 5 min and 54 degrees C for 1 h) and freezing (-20 and -80 degrees C) treatments affected the cultivability and viability of the microbial population. CONCLUSIONS: This study demonstrated the effectiveness of LIVE/DEAD BacLight bacterial viability kit, which has already been used to evaluate bacterial populations, in investigating microbial viability in a complex ecosystem such as a natural whey starter. SIGNIFICANCE AND IMPACT OF THE STUDY: The aim of this study was to quantify the presence of damaged nonviable bacterial cells in natural whey starters. The Thoma Glass is a useful method to obtain fluorescence microscopy counts to evaluate the technological performance of natural whey starters.

Bacteria↗

PubMed2002

Microbial contamination of medicinal plants--a review.

Medicinal plants may be associated with a broad variety of microbial contaminants, which are represented by bacteria, fungi and viruses. Inevitably, this microbiological background depends on several environmental factors and exerts an important impact on the overall quality of herbal products and preparations. Risk assessment of the microbial load of medicinal plants has therefore become an important subject in the establishment of modern Hazard Analysis and Critical Control Point (HACCP) schemes. This study intends to contribute to this knowledge by giving a survey of published data regarding the microbial contamination of herbal plants, by dealing with methodological aspects and by considering the influence of different commonly used pharmaceutical preparation techniques on the microbiological status of the products. Finally, quality standards are discussed, which could be considered for guidelines and/or possible inclusion in the Ph.Eur. 2000.

Bacteria↗

PubMed2001

Contribution of aerobic photoheterotrophic bacteria to the carbon cycle in the ocean.

The vertical distribution of bacteriochlorophyll a, the numbers of infrared fluorescent cells, and the variable fluorescence signal at 880 nanometers wavelength, all indicate that photosynthetically competent anoxygenic phototrophic bacteria are abundant in the upper open ocean and comprise at least 11% of the total microbial community. These organisms are facultative photoheterotrophs, metabolizing organic carbon when available, but are capable of photosynthetic light utilization when organic carbon is scarce. They are globally distributed in the euphotic zone and represent a hitherto unrecognized component of the marine microbial community that appears to be critical to the cycling of both organic and inorganic carbon in the ocean.

Aerobiosis↗

PubMed2006

Foot odor due to microbial metabolism and its control.

To characterize foot odor, we analyzed its components by sensory tests, isolated microorganisms that produce it, and evaluated the mechanism of the occurrence of foot odor. As a result, foot odor was found to be derived from isovaleric acid, which is produced when Staphylococcus epidermidis, a resident species of the normal cutaneous microbial flora, degrades leucine present in sweat. In addition, Bacillus subtilis was detected in the plantar skin of subjects with strong foot odor, and this species was shown to be closely associated with increased foot odor. Therefore, we screened various naturally occurring substances and fragrant agents that inhibit microbial production of foot odor without disturbing the normal microbial flora of the human skin. As a result, we identified citral, citronellal, and geraniol as fragrant agents that inhibit the generation of isovaleric acid at low concentrations.

Acyclic Monoterpenes↗