SEARCH · PubMed Health

Results for “microbial detection”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 397 records · Page 22Linked to original sources

PubMed2005

Microbial contamination of cell cultures: a 2 years study.

Cell line contamination is a major drawback of main cell banks of the world and it has cost of losing important biological products or valuable research. The causative agents are different chemicals, invertebrates, bacteria, fungi, parasites, viral species and even other cell lines. In this retrospective study, cell lines from various species such as human, fish, insect, animals either offered or accessed through usual official accession in CGBRI were studied during 2 years (2002-2004) to detect their microbial contaminations and the causative organisms. Samples were taken for sterility test upon cell lines receipt and upon each cell line sub-culture. Samples were examined for bacterial (including mycoplasmas) and fungal contamination using conventional microbiological techniques. The study excluded parasites, viruses and other contaminating agents. This study revealed 39% of specimens were contaminated. The major contaminating agents were mycoplasmas (19%) followed by mixed infection (8%), fungi (8%) and bacteria (4%). Among various bacterial species (except mycoplasmas) Bacillus sp., Enterococcus sp. and Staphylococcus sp. are main bacterial agents and among various fungi Aspergillus sp. followed by Penicillium sp., Sepedonium sp. and Botrytis sp. were main fungal causative agents of CGBRI cell line contamination. Our study also delineates each cell line contamination rate and its causative agents. This is the first report of cell culture contamination from cell banks of Middle-East countries like Iran.

Animals↗

PubMed2000

Antimicrobial treatment failures in patients with community-acquired pneumonia: causes and prognostic implications.

The aim of the study was to determine the causes and prognostic implications of antimicrobial treatment failures in patients with nonresponding and progressive life-threatening, community-acquired pneumonia. Forty-nine patients hospitalized with a presumptive diagnosis of community-acquired pneumonia during a 16-mo period, failure to respond to antimicrobial treatment, and documented repeated microbial investigation >/= 72 h after initiation of in-hospital antimicrobial treatment were recorded. A definite etiology of treatment failure could be established in 32 of 49 (65%) patients, and nine additional patients (18%) had a probable etiology. Treatment failures were mainly infectious in origin and included primary, persistent, and nosocomial infections (n = 10 [19%], 13 [24%], and 11 [20%] of causes, respectively). Definite but not probable persistent infections were mostly due to microbial resistance to the administered initial empiric antimicrobial treatment. Nosocomial infections were particularly frequent in patients with progressive pneumonia. Definite persistent infections and nosocomial infections had the highest associated mortality rates (75 and 88%, respectively). Nosocomial pneumonia was the only cause of treatment failure independently associated with death in multivariate analysis (RR, 16.7; 95% CI, 1.4 to 194.9; p = 0.03). We conclude that the detection of microbial resistance and the diagnosis of nosocomial pneumonia are the two major challenges in hospitalized patients with community-acquired pneumonia who do not respond to initial antimicrobial treatment. In order to establish these potentially life-threatening etiologies, a regular microbial reinvestigation seems mandatory for all patients presenting with antimicrobial treatment failures.

Community-Acquired Infections↗

PubMed2006

Developing nucleic acid-based electrical detection systems.

Development of nucleic acid-based detection systems is the main focus of many research groups and high technology companies. The enormous work done in this field is particularly due to the broad versatility and variety of these sensing devices. From optical to electrical systems, from label-dependent to label-free approaches, from single to multi-analyte and array formats, this wide range of possibilities makes the research field very diversified and competitive. New challenges and requirements for an ideal detector suitable for nucleic acid analysis include high sensitivity and high specificity protocol that can be completed in a relatively short time offering at the same time low detection limit. Moreover, systems that can be miniaturized and automated present a significant advantage over conventional technology, especially if detection is needed in the field. Electrical system technology for nucleic acid-based detection is an enabling mode for making miniaturized to micro- and nanometer scale bio-monitoring devices via the fusion of modern micro- and nanofabrication technology and molecular biotechnology. The electrical biosensors that rely on the conversion of the Watson-Crick base-pair recognition event into a useful electrical signal are advancing rapidly, and recently are receiving much attention as a valuable tool for microbial pathogen detection. Pathogens may pose a serious threat to humans, animal and plants, thus their detection and analysis is a significant element of public health. Although different conventional methods for detection of pathogenic microorganisms and their toxins exist and are currently being applied, improvements of molecular-based detection methodologies have changed these traditional detection techniques and introduced a new era of rapid, miniaturized and automated electrical chip detection technologies into pathogen identification sector. In this review some developments and current directions in nucleic acid-based electrical detection are discussed.

Journal Article↗

PubMed1993

Controlled comparison of the BACTEC high-blood-volume fungal medium, BACTEC Plus 26 aerobic blood culture bottle, and 10-milliliter isolator blood culture system for detection of fungemia and bacteremia.

The BACTEC high-blood-volume fungal medium (HBV-FM) (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) was compared with the Isolator (IS) tube and the BACTEC Plus 26 (BP26) blood culture bottle for the ability to recover fungi from the blood of adult patients suspected of having fungemia. A total of 6,836 blood culture sets that fulfilled criteria for inclusion in the study were received. Three separate comparisons were performed: 4,907 HBV-FM versus IS, 4,886 BP26 versus HBV-FM, and 4,949 BP26 versus IS. For the HBV-FM versus IS comparison, 218 isolates were recovered: 125 (57.3%) were bacteria and 93 (42.7%) were fungi. HBV-FM was comparable to IS for recovery of yeasts, but IS was superior for recovery of Histoplasma capsulatum (25 versus 0 isolates recovered [P < 0.001]). Growth of Torulopsis glabrata was detected earlier (P < 0.05) in HBV-FM bottles. For the BP26 versus HBV-FM comparison, 229 isolates were recovered: 161 (70.3%) were bacteria, and 68 (29.7%) were fungi. HBV-FM was superior for recovery of T. glabrata (P < 0.025) and all fungi combined (P < 0.025). There were no statistically significant differences in the speed of detection of microbial growth. For the BP26 versus IS comparison, 251 isolates were recovered: 165 (65.7%) were bacteria, and 86 (34.2%) were fungi. IS was superior for recovery of H. capsulatum (P < 0.001), T. glabrata (P < 0.05), and fungi other than H. capsulatum (P < 0.025). BP26 was superior for recovery of all bacteria combined (P < 0.001) and viridans group streptococci (P < 0.01). Growth of T. glabrata (P < 0.05) was detected earlier in IS tubes. Growth of Staphylococcus aureus (P < 0.01), viridans group streptococci (P < 0.01), Pseudomonas aeruginosa (P < 0.05), and all microorganisms combined (P < 0.05) was detected earlier in BP26 bottles. For yeast, 57 of 59 (96.6%), 79 of 80 (98.7%), and 64 of 67(95.5%) were recovered from BP26 bottles, HBV-FM bottles, and IS tubes, respectively, by day 14; for H. capsulatum, 14 of 36 (38%) isolates were recovered from IS tubes by day 14. Mean times of recovery were similar for BACTEC bottles and IS. We conclude that (i) for recovery of fungi from blood cultures, HBV-FM is equivalent to IS (with the exception of H. capsulatum); (ii) for recovery of bacteria, BP26 is superior to IS; (iii) BP26 bottles are inferior to both HBV-FM bottles and IS tubes for recovery of T. glabrata; and (iv) HBV-FM bottles must be paired with another blood culture bottle or system to optimize detection of bacteremia.

Aerobiosis↗

PubMed1997

Electrochemical disinfection of drinking water using an activated-carbon-fiber reactor capable of monitoring its microbial fouling.

An electrochemical reactor employing activated carbon fibers (ACF) was constructed for the disinfection of bacteria in drinking water. The application of an alternating potential of 1.0 V and -0.8 V versus a saturated calomel electrode, for disinfecting and desorbing bacteria, enabled reactor operation for 840 h. Drinking water was passed through the reactor in stop/flow mode: 300 ml/min flow for 12 h and no flow for 12 h, alternately. The bacterial cell density in treated water was always been less than 20 cells/ml. It was also found that the formation of biofilm on the ACF reactor caused an increase in current, enabling the self-detection of microbial fouling.

Absorption↗

PubMed2002

Diversity, dynamics, and activity of bacterial communities during production of an artisanal Sicilian cheese as evaluated by 16S rRNA analysis.

The diversity and dynamics of the microbial communities during the manufacturing of Ragusano cheese, an artisanal cheese produced in Sicily (Italy), were investigated by a combination of classical and culture-independent approaches. The latter included PCR, reverse transcriptase-PCR (RT-PCR), and denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes (rDNA). Bacterial and Lactobacillus group-specific primers were used to amplify the V6 to V8 and V1 to V3 regions of the 16S rRNA gene, respectively. DGGE profiles from samples taken during cheese production indicated dramatic shifts in the microbial community structure. Cloning and sequencing of rDNA amplicons revealed that mesophilic lactic acid bacteria (LAB), including species of Leuconostoc, Lactococcus lactis, and Macrococcus caseolyticus were dominant in the raw milk, while Streptococcus thermophilus prevailed during lactic fermentation. Other thermophilic LAB, especially Lactobacillus delbrueckii and Lactobacillus fermentum, also flourished during ripening. Comparison of the rRNA-derived patterns obtained by RT-PCR to the rDNA DGGE patterns indicated a substantially different degree of metabolic activity for the microbial groups detected. Identification of cultivated LAB isolates by phenotypic characterization and 16S rDNA analysis indicated a variety of species, reflecting to a large extent the results obtained from the 16S rDNA clone libraries, with the significant exception of the Lactobacillus delbrueckii species, which dominated in the ripening cheese but was not detected by cultivation. The present molecular approaches combined with culture can effectively describe the complex ecosystem of natural fermented dairy products, giving useful information for starter culture design and preservation of artisanal fermented food technology.

Cheese↗

PubMed1999

Study on microbial persistence in end-stage idiopathic dilated cardiomyopathy.

Microbial persistence may be involved in the pathogenesis of idiopathic dilated cardiomyopathy (IDC). Therefore, we evaluated the role of various cardiopathogenic microorganisms in patients with end-stage IDC. In a previous study, we did not find evidence for the persistence of enterovirus RNA in end-stage IDC. In the present study, we looked for other microorganisms that are frequently associated with heart disease, including cytomegalovirus, hepatitis B virus, hepatitis C virus, Borrelia burgdorferi, Chlamydia species, mycoplasmata, and Toxoplasma gondii. Serology, polymerase chain reaction (PCR) analysis specific for detection of microbial genomic sequences, or both investigations were performed on myocardial samples from 37 patients with end-stage IDC. PCR analysis was performed on multiple myocardial samples per patient. Thirty-nine patients with end-stage heart disease of known cause were included as controls. On the basis of our serological data and PCR analyses, we did not find any evidence that microbial persistence in the heart is involved in the end-stage disease process of IDC.

Adolescent↗

PubMed2003

Microbial transformation of naproxen by Cunninghamella species.

AIM: The metabolites of naproxen produced by Cunninghamella species were isolated and identified, and further to compare the similarities between microbial transformation and mammalian metabolism. METHODS: Naproxen was transformed by three strains of Cunninghammella species (Cunninghamella blakeslesna AS 3.153, Cunninghamella echinulata AS 3.2004, and Cunninghamella elegans AS 3.156). The metabolites of naproxen were separated and assayed by liquid chromatography-mass spectrometry method. Semi-preparative HPLC was used to isolate the major metabolite, and the structure was identified by nuclear magnetic resonance (NMR) and mass spectrometry. RESULTS: Naproxen was transformed into 2 metabolites, desmethylnaproxen and desmethylnaproxen-6-O-sulfate, both were the known mammalian metabolites. The conjugated metabolite was newly detected in microbial transformation samples. CONCLUSION: The microbial transformation of naproxen has some similarities with the metabolism of naproxen in mammals. The fungi belonging to Cunninghamella species could be used as complementary in vitro models for drug metabolism to predict and produce the metabolites of drugs in mammals.

Biotransformation↗

PubMed1993

Multiplex polymerase chain reaction for detection and differentiation of the microbial insecticide Bacillus thuringiensis.

A rapid identification of Bacillus thuringiensis strains was established by using multiplex polymerase chain reaction (PCR). Primers of high homology specific to regions within genes encoding three major classes of B. thuringiensis crystal proteins were used to generate a PCR product profile characteristic of each strain of B. thuringiensis subsp. kurstaki. Differentiation among these strains was made on the basis of the electrophoretic pattern of the PCR products. Known B. thuringiensis subsp. kurstaki strains as well as unidentified strains isolated from insect cadavers were analyzed by PCR. Small amounts of crude sample lysates were assayed in a two-step PCR containing five primers capable of distinguishing between the strains giving products of 1,500, 858, and 653 bp for the CryIA(a) CryIA(b), and CryIA(c) genes, respectively. The method can be applied to rapidly detect the strains of B. thuringiensis subsp. kurstaki in commercial formulations and in the field.

Animals↗

PubMed2003

Culture-independent analysis of probiotic products by denaturing gradient gel electrophoresis.

In order to obtain functional and safe probiotic products for human consumption, fast and reliable quality control of these products is crucial. Currently, analysis of most probiotics is still based on culture-dependent methods involving the use of specific isolation media and identification of a limited number of isolates, which makes this approach relatively insensitive, laborious, and time-consuming. In this study, a collection of 10 probiotic products, including four dairy products, one fruit drink, and five freeze-dried products, were subjected to microbial analysis by using a culture-independent approach, and the results were compared with the results of a conventional culture-dependent analysis. The culture-independent approach involved extraction of total bacterial DNA directly from the product, PCR amplification of the V3 region of the 16S ribosomal DNA, and separation of the amplicons on a denaturing gradient gel. Digital capturing and processing of denaturing gradient gel electrophoresis (DGGE) band patterns allowed direct identification of the amplicons at the species level. This whole culture-independent approach can be performed in less than 30 h. Compared with culture-dependent analysis, the DGGE approach was found to have a much higher sensitivity for detection of microbial strains in probiotic products in a fast, reliable, and reproducible manner. Unfortunately, as reported in previous studies in which the culture-dependent approach was used, a rather high percentage of probiotic products suffered from incorrect labeling and yielded low bacterial counts, which may decrease their probiotic potential.

Bacteria↗

PubMed2026

Whole metagenome sequencing: not deep enough for complete microbial function recovery.

BACKGROUND: Whole metagenome shotgun sequencing (WMS) is widely used to profile microbial function. However, technical variability in sequencing and analysis often obscures true biological patterns. Large-scale studies are particularly susceptible to batch effects, such as differences in sequencing depth and platform and annotation strategies, as well as sample-to-flow-cell assignments. However, the relative effects of these factors on functional inference in such studies have yet to be systematically evaluated. We analyzed oral-rinse WMS data from 671 Nigerian youths aged 9-18, sequenced on two Illumina platforms. Microbial molecular functionality encoded in these data was annotated using the mi-faser/Fusion pipeline, to capture the broad functional repertoire, and HUMAnN 3/EC numbers pipeline to characterize curated enzymatic activities. We then quantified how technical factors and batch effects shaped the recovery of microbial functionality. RESULTS: Three findings of our work were most salient. First, we observed that the choice of annotation strategy traded off between breadth and specificity of functional coverage. Second, we found that low-prevalence functions were disproportionately lost at shallow sequencing depths, indicating that in, e.g., case-control studies with few representatives of the minor class, sequencing depth could critically impact study resolution. Finally, using our newly developed model relating sequencing depth to functional recovery, we demonstrated that increasing sequencing depth does not directly or proportionally improve functional recall. That is, at as little as 10% of this study's sequencing depth, 30% of the estimated complete microbiome functional repertoire was detectable. However, even at the full depth used in this study, we were only able to recover an estimated 60% of that complete functional repertoire. We further showed that despite biomes differences in functional diversity and host contamination levels (e.g., soil, fecal), incomplete functional recovery at commonly used sequencing depths was consistently observed. CONCLUSIONS: Together, these findings and our depth-to-function mapping framework provide practical guidelines for the design and interpretation of WMS studies. Coordinating sequencing depth planning with annotation strategy, experimental design, and rigorous batch control is thus essential for robust detection of microbial functions and for ensuring reproducible microbiome insights. Video Abstract.

Humans↗

PubMed2026

Employing Metagenomics Capture targeted next-generation sequencing for the etiological diagnosis of bloodstream infections.

BACKGROUND: Bloodstream infections (BSIs) represent a significant public health concern. Metagenomic Capture targeted next-generation sequencing technology, as a newly emerging method for pathogen detection, has been applied in the etiological diagnosis of various infectious diseases and demonstrates good diagnostic efficacy. However, there is relatively limited research on the diagnostic value of this technology for the etiological diagnosis of BSIs. METHODS: A comprehensive retrospective analysis was performed on patients suspected of having BSIs who were admitted to the Affiliated Guangdong Second Provincial General Hospital of Jinan University in 2024. These patients underwent both blood culture analysis and Metagenomic Capture targeted next-generation sequencing technology for diagnostic testing, and a detailed comparison of the results was conducted. RESULTS: It was found that the Metagenomic Capture-targeted next-generation sequencing method has a shorter time to result [1.33 (1.18 - 1.69) vs 2.73 (1.89 - 3.84) days, p < 0.001], more pathogenic microbial species detected, higher positive detection rate and higher sensitivity than blood culture. CONCLUSIONS: Metagenomic Capture targeted next-generation sequencing technology is a promising tool for pathogen identification in BSIs, offering substantial methodological advantages in terms of turnaround time, detection breadth, and sensitivity. These diagnostic performance characteristics support its potential utility in clinical microbiology practice.

Humans↗

PubMed2004

High-throughput mutation detection underlying adaptive evolution of Escherichia coli-K12.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis of base-specific cleavage products is an efficient, highly accurate tool for the detection of single base sequence variations. We describe the first application of this comparative sequencing strategy for automated high-throughput mutation detection in microbial genomes. The method was applied to identify DNA sequence changes that occurred in Escherichia coli K-12 MG1655 during laboratory adaptive evolution to new optimal growth phenotypes. Experiments were based on a genome-scale in silico model of E. coli metabolism and growth. This model computes several phenotypic functions and predicts optimal growth rates. To identify mutations underlying a 40-d adaptive laboratory evolution on glycerol, we resequenced 4.4% of the E. coli-K12 MG1655 genome in several clones picked at the end of the evolutionary process. The 1.54-Mb screen was completed in 13.5 h. This resequencing study is the largest reported by MALDI-TOF mass spectrometry to date. Ten mutations in 40 clones and three deviations from the reference sequence were detected. Mutations were predominantly found within the glycerol kinase gene. Functional characterization of the most prominent mutation shows its metabolic impact on the process of adaptive evolution. All sequence changes were independently confirmed by genotyping and Sanger-sequencing. We demonstrate that comparative sequencing by base-specific cleavage and MALDI-TOF mass spectrometry is an automated, fast, and highly accurate alternative to capillary sequencing.

Adaptation, Biological↗

PubMed1993

Sub-gingival microflora in Macaca mulatta species of rhesus monkey.

The Macaca mulatta species of rhesus monkey is one of several non-human primate (nhp) models for periodontal disease. This report presents the bacteriology of the gingival sulci in M. mulatta monkeys. Three sub-gingival sites (maxillary right central incisor, the disto-buccal of the mandibular left second molar and mesio-buccal of the mandibular right second molar) of 9 monkeys were evaluated clinically before scaling and 7 days after scaling. Plaque samples were obtained from sub-gingival sites before clinical examination and studied bacteriologically by dark field microscopy, selective and non-selective culture, and by primary phenotypic characterizations of culture isolates. Several gingival sites presented with mild gingival inflammation. Anaerobic and facultatively anaerobic bacteria were the predominant flora colonizing the gingival sulci. The major microbial groups were Haemophilus species (100% of sites; percentage of total anaerobic count (TAC): 21-51), Peptostreptococcus micros (89%, 7.5-29.5), Actinomyces sp. (85%, 7-27), Fusobacterium nucleatum (90%, 5-8), Actinobacillus actinomycetemcomitans (73%, 1.3-12), black-pigmented anaerobic rods (BPAR) (80%, 0.6-6.5) and oral streptococci (80%, 0.2-1.0). Microbial groups detected less often were Wolinella sp. (66%, 0-2.6), Capnocytophaga sp. (30%), Eikenella corrodens (4.7%, 0), Campylobacter sp. (28%, 0-0.1) and spirochetes (4.7%, 0-0.07). Seven days after gingival sites were scaled, the plaque score and indices for gingival inflammation declined significantly. The gingival flora after scaling were characterized by lower proportions of the Actinomyces sp., P. micros and BPAR; and increased proportions of the oral streptococci, relative to pre-scaling levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomyces↗

PubMedDate not supplied

Subgingival microflora in smokers with early onset periodontitis.

Cigarette smoking is a potent risk factor which has recently been associated with periodontal disease progression. The objective of this study was to detect the microbial profile of early onset periodontitis in smokers and compare it to that of non-smokers. The study population consisted of 50 systemically healthy individuals aged 25 to 38 years, exhibiting early onset periodontitis. 25 patients were smokers (> 20 cigarettes/day) and 25 non-smokers. Two pooled bacterial samples comprised of four periodontal sites with probing depth > 5 mm each, were collected from each individual. The samples were cultured aerobically and anaerobically for bacterial isolation using selective and non-selective media. Isolates were characterized to species level by conventional biochemical tests and various identification kits. The differences in bacterial counts using the Mann Whitney U test were statistically significant for Staphylococcus aureus, Campylobacter concisus, Eikenella corrodens, Escherichia coli, Bacteroides forsythus, Bacteroides gracilis, Campylobacter rectus, Porphyromonas gingivalis, Selenomonas sputigena and Candida albicans in smokers. Statistically significant differences for Peptostreptococcus micros, Actinomyces naeslundii, Eubacterium lentum and Capnocytophaga gingivalis were detected in non-smokers. The isolation of bacteria belonging to the exogenous flora like E. coli, C. albicans and S. aureus in smokers microflora underscores the importance of the host which is adversely affected by cigarette smoking.

Journal Article↗

PubMed2006

Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.

The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations.

Anti-Infective Agents↗

PubMed2002

Assessment of handwashing practices with chemical and microbiologic methods: preliminary results from a prospective crossover study.

BACKGROUND: Handwashing (HW) by clinical staff is the single most important measure for preventing transmission of nosocomial infection (NI). The primary objectives of this study were to improve the motivation and awareness of the importance of HW practices among health care workers (HCWs) and to assess the effectiveness of a new chemical system in checking HW compliance. In addition, we evaluated the efficacy and tolerability of 2 soap solutions used during regular working hours by HCWs at our institution. METHOD: A preliminary short training course was performed to promote HW compliance and awareness. We chose 2 surgical wards at our 1200-bed teaching hospital. Sampling of hands was conducted weekly during routine activities of HCWs without advance warning. We used the staff list as a sampling frame to select subjects. Data were collected anonymously. On the basis of a crossover study design, a plain soap and one containing 4% chlorhexidine gluconate (CHG) were used alternatively in each ward for 4 consecutive months. Hand samples were evaluated with microbiologic cultures and with a commercially available kit that measures adenosine triphosphate (ATP) bioluminescence. As additional process indicators, we examined the amount of hand soap and CHG solution distributed and rate of NIs. RESULTS: A total of 74 HCWs were evaluated for hand contamination. During the 4-month study, we found a significant reduction in colony-forming unit counts (P <.008) and ATP levels (P <.002) compared with baseline values. The results showed a positive correlation (r = 0.68, P <.0001) between the microbial counts detected by standard culture and ATP levels measured with the commercial kit. Plain soap (P <.003) was more effective than CHG in reducing colony-forming unit counts among HCWs in the vascular surgery ward. We documented a reduction in the NI rate and an increase in the consumption of soap and paper towels. CONCLUSION: HW compliance improved during the study period among HCWs. The method to measure ATP bioluminescence is simple and easy to perform and provides reliable results within a few minutes of sampling hands. It can be used extensively to test HW compliance among HCWs.

Adenosine Triphosphate↗

PubMedDate not supplied

[Biogeochemical processes in the algal-bacterial mats of the Urinskii alkaline hot spring].

The structure and production characteristics of microbial communities from the Urinskii alkaline hot spring (Buryat Republic, Russia) have been investigated. A distinctive characteristic of this hot spring is the lack of sulfide in the issuing water. The water temperature near the spring vents ranged from 69 to 38.5 degrees C and pH values ranged from 8.8 to 9.2. The total mineralization of water was less than 0.1 g/liter. Temperature has a profound effect on the species composition and biogeochemical processes occurring in the algal-bacterial mats of the Urinskii hot spring. The maximum diversity of the phototrophic community was observed at the temperatures 40 and 46 degrees C. A total of 12 species of cyanobacteria, 4 species of diatoms, and one species of thermophilic anoxygenic phototrophic bacteria, Chloroflexus aurantiacus, have been isolated from mat samples. At temperatures above 40 degrees C, the filamentous cyanobacterium Phormidium laminosum was predominant; its cell number and biomass concentration were 95.1 and 63.9%, respectively. At lower temperatures, the biomass concentrations of the cyanobacterium Oscillatoria limosa and diatoms increased (50.2 and 36.4%, respectively). The cyanobacterium Mastigocladus laminosus, which is normally found in neutral or slightly acidic hydrothermal systems, was detected in microbial communities. As the diatom concentration increases, so does the dry matter concentration in mats, while the content of organic matter decreases. The concentrations of proteins and carbohydrates reached their maximum levels at 45-50 degrees C. The maximum average rate of oxygenic photosynthesis (2.1 g C/m2 day), chlorophyll a content (343.4 mg/m2), and cell number of phototrophic microorganisms were observed at temperatures from 45 to 50 degrees C. The peak mass of bacterial mats (56.75 g/m2) occurred at a temperature of 65-60 degrees C. The maximum biomass concentration of phototrophs (414.63 x 10(-6) g/ml) and the peak rate of anoxygenic photosynthesis [0.42 g C/(m2 day)] were observed at a temperature of 35-40 degrees C.

Algal Proteins↗