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PubMed1966

Isolated fecal microorganisms capable of 7-alpha-dehydroxylating bile acids.

Strains of microorganisms capable of 7alpha-dehydroxylation of chenodeoxycholate were isolated from rat and human feces. All the strains were strictly anaerobic, non-motile, moderately themioresistant Gram-positive rods. They showed some saccharolytic properties with the production of both acid and gas. They were H(2)S-positive but indole-, skatole-, citrate-, catalase-, and oxidase-negative. The isolated strains capable of 7alpha-dehydroxylation of chenodeoxycholate were also able to oxidize the hydroxyl groups at C-3 and C-7 to keto groups. The following metabolites were isolated: 3-keto-7alpha-hydroxy-5beta-cholanoic acid, 3alpha-hydroxy-7-keto-5beta-cholanoic acid, 3alpha-hydroxy-5beta-cholanoic acid, and 3-keto-5beta-cholanoic acid. The isolated strains did not have the enzymes necessary for hydrolyzing conjugated bile acids. In mixed anaerobic cultures of fecal microorganisms, extensive reduction of the 3-keto group to the 3beta-hydroxyl group occurred. The microorganism(s) responsible for this reaction have as yet not been isolated.

Bacteriological Techniques↗
PubMed2006

Blood pressure cuff as a potential vector of pathogenic microorganisms: a prospective study in a teaching hospital.

OBJECTIVE: To investigate the potential role of blood pressure (BP) cuffs in the spread of bacterial infections in hospitals. DESIGN: A comprehensive, prospective study quantitatively and qualitatively evaluating the bacterial contamination on BP cuffs of 203 sphygmomanometers in use in 18 hospital units from January through March 2003. SETTING: A university hospital with surgical, medical, and pediatric units. RESULTS: A level of contamination reaching 100 or more colony-forming units per 25 cm(2) was observed on 92 (45%) of inner sides and 46 (23%) of outer sides of 203 cuffs. The highest rates of contamination occurred on the inner side of BP cuffs kept in intensive care units (ICUs) (20 [83%] of 24) or on nurses' trolleys (27 [77%] of 35). None of the 18 BP cuffs presumed to be clean (ie, those that had not been used since the last decontamination procedure) had a high level of contamination. Potentially pathogenic microorganisms were isolated from 27 (13%) of the 203 BP cuffs: 20 of these microorganisms were Staphylococcus aureus, including 9 methicillin-resistant strains. The highest rates of contamination with potentially pathogenic microorganisms were observed on cuffs used in ICUs and those kept on nurses' trolleys. For 4 patients with a personal sphygmomanometer, a genetic link was found between the strains isolated from the BP cuffs and the strains isolated from the patients. CONCLUSIONS: The results of this survey highlight the importance of recognizing BP cuffs as potential vectors of pathogenic bacteria among patients and as a source of reinfection when dedicated to a single patient, emphasizing the urgent need for validated procedures for their use and maintenance.

Bacteria↗
PubMed1994

Predominance of gram-positive microorganisms as a cause of septicemia in patients with hematological malignancies.

OBJECTIVE: To ascertain the etiology and outcome of episodes of bacteremia and fungemia over a three-year period (1990-1992) in patients with hematological malignancies. DESIGN: Retrospective study. SETTING: Hematology service of a 1,500-bed Spanish university hospital. RESULTS: Of a total of 178 episodes of significant bacteremia or fungemia in 101 patients, 53% affected patients with acute leukemia. Gram-positive microorganisms were found to be the cause in 70% of the monomicrobial episodes. The most frequently isolated microorganism was coagulase-negative Staphylococcus (35%), followed by Staphylococcus aureus (11%). Most blood-stream infections occurred during an episode of neutropenia (59%). A total of 34 patients died during hospitalization; in 14, infection was the cause of death. CONCLUSIONS: A marked increase in the incidence of bacteremias caused by gram-positive microorganisms has been observed in our hospital over the last 10 years, especially in patients with hematological malignancies. The mortality due to bacteremia is similar to that found by other authors in series of bacteremia in hematological patients, and we have not found significant differences in the mortality due to bacteremia between neutropenic and non-neutropenic patients (Infect Control Hosp Epidemiol 1994;15:101-104).

Adolescent↗
PubMed1975

Effect of microorganisms isolated from the upper gut of malnourished children on intestinal sugar absorption in vivo.

The effect of microorganisms isolated from the upper gastrointestinal tract of malnourished children on intestinal sugar absorption was studied in rats in vivo. Pure cultures of organisms were grown overnight in a nutrient broth and the resultant supernatant fluid which contained microorganisms in similar numbers to those found in the patients was used as the basic solution for jejunal perfusions which were done in anesthetized adult Wistar rats. The substrate used was arbutin (p-hydroxphenyl-beta-glucoside), a recognized marker of intestinal active sugar transport. Of the gram-positive cocci studied, only the saprophyte, Staphylococcus saprophyticus, did not adversely affect the intestinal absorption of arbutin. The only gram-positive rod studied, a lactobacillus, also significantly inhibited arbutin absorption. Of the Enterobacteriaciae studied, Salmonella paratyphi B, a Shigella and Proteus sp. did not affect arbutin absorption. All the species of Escherichia coli studied, including a nonpathogenic variety, inhibited absorption. Klebsiella sp. and Pseudomonas sp. were also effective. Of the Candida sp., C. albicans and C. parapsilosis were inhibitory while C. tropicalis was not. These results suggest that microorganisms not generally considered enteropathogenic may adversely affect intestinal function when present in the lumen of the gut in excessive numbers and contribute to the production of diarrhea in children with malnutrition.

Animals↗
PubMedDate not supplied

Radiolabeled microorganisms: comparison of different radioisotopic labels.

Radioactively labeled microorganisms are very useful in assessing the in vitro phagocytic capability of human granulocytes and macrophages. Since microorganisms contain amino acids and nucleic acids, they can be radiolabeled by addition of radioactive amino acid and/or nucleic acid components to the culture medium. The isotopes 3H, 14C, 32P, 35S, and 75Se-have been used for bacterial radiolabeling. All of these commonly used isotopes with the exception of 75Se are beta emitters; 75Se is a gamma emitter. The half-lives of these isotopes vary from 14 days for 32P to 5,730 years for 14C. Because of the differences in their physical properties, they pose very different handling problems and require different kinds of safety precautions. In the event of either external or internal contamination, beta emitters deliver a larger localized radiation dose than do gamma emitters. In the case of internal contamination, the radiation dose increases with increases in the half-life of the radioactive isotope. Gamma radiation, on the other hand, is more penetrating than are beta particles and thus a gamma emitter requires appropriate shielding. Both the cost and the special problem of manipulation associated with these radioactive chemicals should be carefully considered before deciding which radioisotope is preferable for the labeling of microorganisms in the laboratory. In spite of the limitations of 75Se as a nonphysiologic element, it offers the simplest methods of handling among the isotopes considered in this review.

Bacteria↗
PubMed1998

Bioaccumulation and biosorption of lead by poultry litter microorganisms.

Microorganisms are known to interact with metals through a number of mechanisms, including binding the metals to their cells' walls and intracellular accumulation. Poultry litter has a high density of various microorganisms along with many nutrients. The objective of this research was to study the removal of Pb from an aqueous solution by the microorganisms found in poultry litter under an aerobic environment. A Pb(NO3)2 solution was treated with the aqueous extract of either the nonradiated litter or gamma-radiated litter in order to differentiate between the removal of Pb through bioaccumulation (by the living organisms) and biosorption (by the dead organisms). Lead removal was measured using anodic stripping voltammetry. Both the nonradiated and the gamma-radiated litter removed significant amounts of Pb. After 14 d, the amount of Pb removed through bioaccumulation by the nonradiated litter and through biosorption by the radiated litter was about 44 and 30%, respectively. There was no increase in Pb removal between 14 and 60 d. The biomass density of the aqueous extract of poultry litter increased significantly in the presence of 400 ppb Pb(NO3)2.

Absorption↗
PubMed1996

Growth of microorganisms in propofol, thiopental, and a 1:1 mixture of propofol and thiopental.

To assess and compare the growth of four microorganisms in solutions of intravenous anesthetics, known quanta of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were inoculated into propofol, thiopental, a 1:1 mixture of propofol and thiopental, and normal saline. All microorganisms were taken from standard stock cultures and incubated for 24 h (48 h for C. albicans). Growth of microorganism in each drug was compared by counting the number of colony forming units (CFUs) grown from a subculture of each inoculated anesthetic at 0, 3, 6, 12, and 24 h. The study shows that propofol strongly supports the growth of E. coli and C. albicans but is bacteriostatic toward S. aureus and weakly bactericidal toward P. aeruginosa. In contrast, both thiopental and the 1:1 mixture of propofol and thiopental behaved differently, exhibiting markedly bactericidal properties toward E. coli, S. aureus, and P. aeruginosa and a bacteriostatic effect on C. albicans. This finding supports recommendations that a strict aseptic technique should be used when handling propofol and that the contents of an ampoule should be used within 6 h of aspirating. The measured high pH of both thiopental and the 1:1 mixture of propofol and thiopental compared to propofol alone suggests pH to be a major factor in determining whether a given drug will support microbial growth.

Anesthetics, Intravenous↗
PubMed1991

In vitro adhesion of endogenous skin microorganisms to breast prostheses.

Bacterial proliferation on polymeric biomaterials varies with the material and microorganism. Subclinical infection is implicated frequently as the initiative factor in capsular contracture around breast prostheses. The ability of endogenous skin microorganisms to produce an exopolysaccharide "slime" is emerging as an important factor in biomaterial colonization. This study was designed to demonstrate the ability of microorganisms of varying slime productivity to colonize, in vitro, different kinds of breast prostheses. Six-millimeter disks from seven kinds of silicone prostheses and polyurethane foam were exposed to three radioactivity labeled strains of bacteria, one slime producer, and two non-slime producers, for 1 hour. Data were expressed as colony-forming units bound per disk. There was no significant difference in adherence between the bacterial strains used, suggesting that initial adherence was nonspecific. The adherence did not appear to be related to surface type, whether smooth or textured, nor to the polymeric composition of the implant material, whether silicone or polyurethane, nor to the presence or absence of slime. Also, adherence was consistent with expected nonspecific bacterial adherence to biomaterials.

Bacterial Adhesion↗
PubMed1978

Host defense against opportunist microorganisms following trauma. I. Studies to determine the association between changes in humoral components of host defense and septicemia in burned patients.

Total hemolytic complement (CH(50)), conversion of C3 by inulin, and immunochemical levels of Clq, C4, C2, C3, C5, factor B, C3b inactivator (KAF), and properdin were measured in the sera of 15 patients with severe thermal injury during nine weeks postburn. Five of the 15 patients had multiple episodes of septicemia as documented by positive blood cultures and clinical findings. Decrease in CH(50), Clq, C4, C2, C3, and C5 occurred prior to and during septic episodes in these patients. Although conversion of C3 by inulin was often reduced during septic episodes, levels of factor B and KAF were generally normal or elevated. In only one patient did consumption of complement occurring during septicemia decrease the opsonic capacity of the patient's sera for the patient's infecting microorganism, an isolate of E. coli; sera from the same patient opsonized her infecting strain of S. aureus normally. The microorganisms isolated from the other septic patients, which were opsonized normally by the patients' sera despite complement consumption, were also with one exception strains of Staphylococci. In the nonseptic burned patients, decrease in properdin and C3 conversion by inulin, and increase in C3, factor B and KAF were demonstrated as we have previously reported. The results indicate that the classical complement pathway was activated during septicemia in burned patients and that activation of this pathway occurred preferentially due to inhibition of the alternative pathway. In addition, the data show that complement consumption may reduce the opsonic capacity of a patient's sera for certain microorganisms and not for others.

Adolescent↗
PubMed2002

EM evaluation of bacterial biofilm and microorganisms on the apical external root surface of human teeth.

The aim of this study was to evaluate the presence of bacterial biofilm on the external surface of the root apex in teeth with pulp necrosis, with and without radiographically visible periapical lesions, and in teeth with a vital pulp. Twenty-one teeth were extracted, eight with pulp necrosis and periapical lesions, eight with pulp necrosis without radiographically visible periapical lesions, and five with a vital pulp. The roots were sectioned, and the root apexes (+/- 3 mm) were processed for scanning electron microscope evaluation. The surface of the apical root was evaluated for the presence of microorganisms, root resorption, and biofilm. There were no microorganisms on the apical root surface of either teeth with pulp vitality or with pulp necrosis with no radiographically visible periapical lesions. Microorganisms were always present in teeth with pulp necrosis and radiographically visible periapical lesions. These included cocci, bacilli, and filaments and the presence of an apical biofilm. Apical biofilm is clinically important because microbial biofilms are inherently resistant to antimicrobial agents and cannot be removed by biomechanical preparation alone. This may cause failure of endodontic treatment as a consequence of persistent infection.

Biofilms↗
PubMedDate not supplied

How drug-resistant microorganisms affect nursing.

Although antibiotics have improved the mortality and morbidity associated with infectious disease, antibiotic mismanagement has created drug-resistant microorganisms, which are present in the environment outside the hospital. In the hospital, drug-resistant microorganisms require Contact Isolation, a transmission-based isolation recommended by the Centers for Disease Control and Prevention. The nurse's role in preventing the spread of drug-resistant microorganisms includes using appropriate infection control and isolation guidelines (especially handwashing), working with other health care workers to maintain appropriate infection control standards at all times, and teaching patients and families about infection control and antibiotic management.

Bacterial Infections↗
PubMed1991

Immunoglobulins coat microorganisms of skin surface: a comparative immunohistochemical and ultrastructural study of cutaneous and oral microbial symbionts.

Only recently have human sweat glands been demonstrated to secrete immunoglobulins (Ig), paralleling Ig secretion in mucosal epithelia. It is well established that Ig protect mucosal membranes against infections by binding to surface structures of microorganisms. In view of these findings immunohistochemical studies were performed to determine if microbes on the skin surface are coated by Ig as proposed for mucosal bacteria and fungi. Smear preparations from the skin and oral cavity rich in micro-organisms were subjected to immunoperoxidase staining using anti-secretory component (SC), -IgA, -IgM, -IgG antibodies. An immunogold labeling technique of microbial suspensions of sweat and saliva was adapted to correlate the results on an ultrastructural level. Negative controls included unsuccessful staining for IgA in preparations obtained from an IgA-deficient patient as well as nonreactivity of subcultured microorganisms for all Ig classes or SC. Smear preparations from both the oral cavity and skin surface exhibited labeling of bacterial or fungal elements with anti-IgA, -IgM, -IgG, and -SC antibodies. Skin bacteria revealed a lower number of reactive microbes as compared to saliva. Staining intensity for the different Ig classes exhibited intra- and interindividual variations. Immunoelectronmicroscopically, Ig and SC could be detected either directly along the cell wall of coccal, coryneform, and fungal elements or on floccular and fimbrial material adhering to the bacterial surface. It is concluded that secretory Ig of the skin cover surface structures of microorganisms and thus modify their adhesional and/or infectious properties, resembling humoral surface immunity on mucous membranes.

Adult↗
PubMed1987

A simple metachromatic and fluorescent staining method for microorganisms using carbocyanine dye.

The cationic carbocyanine dye, 1-ethyl-2-[3-(1-ethylnaphtho[1, 2d]-thiazolin-2-ylidene)-2-methylpropenyl]-naphtho[1, 2d]thiazolium bromide, interacts with several classes of anionic polymers, exhibiting metachromasia. We were able to stain various kinds of microorganisms with this dye. Gram-negative bacteria were stained reddish purple, while Gram-positive bacteria were stained violet or bluish purple. Stains of molds were of various colors. Yeast vegetative cells were stained reddish purple, but zygotic asci were bluish. Chlamydia trachomatis inclusions, which are surrounded by cytoplasmic membranes, were also stained red. Microorganism and cell stains have different features and can be identified also by use of fluorescent microscopy. The new staining method we report here is rapid and simple enough for routine microscopical examinations of smears of clinical specimens including microorganisms.

Adult↗
PubMed1994

Peroxidase-positive round cells and microorganisms in human semen together with antibiotic treatment adversely influence the outcome of in-vitro fertilization and embryo transfer.

Human semen contains not only spermatozoa but also other cells routinely differentiated as being peroxidase-positive (e.g. leucocytes) and peroxidase-negative (e.g. immature germ cells and lymphocytes) cells. Considerable uncertainty exists about their role in male fertility. To assess the clinical value of both parameters, and of microorganisms in semen, 391 treatments with in-vitro fertilization and embryo transfer were analysed retrospectively, and the concentrations of both peroxidase-positive and -negative cells, together with the presence of microorganisms in semen, were compared with both the fertilization and pregnancy rates. The data indicate that the results of treatment were affected only by excessively elevated concentrations of peroxidase-positive cells (> 6 x 10(6)/ml) and only marginally by the presence of microorganisms in the semen. The pregnancy rate after in-vitro fertilization and embryo transfer was not improved by antibiotic treatments preceding gamete recovery by several weeks. The increased presence of peroxidase-negative cells (e.g. germ cells) in semen was not associated with a significant change in the pregnancy rate. However, the concentration of peroxidase-negative cells in semen correlated significantly with sperm numbers (p < 0.01), sperm concentration (p < 0.01), and normal morphology rates (p < 0.01). It is concluded that short-term antibiotic treatment of asymptomatic patients before assisted reproduction should be handled with caution. The widespread view that peroxidase-negative cells in semen are harmful is rejected.

Anti-Bacterial Agents↗
PubMed2005

Adhesion to sole, Solea senegalensis Kaup, mucus of microorganisms isolated from farmed fish, and their interaction with Photobacterium damselae subsp. piscicida.

Abstract Most studies carried out to select microorganisms as candidate probiotics have focused on in vitro antagonism tests, such as the production of inhibitory compounds against pathogenic microorganisms. However, attachment to mucous surfaces could be another criterion to be considered when selecting potential probiotics for aquaculture. Nineteen isolates obtained from farmed Senegalese sole, Solea senegalensis Kaup, and gilthead sea bream, Sparus aurata L., have been evaluated for their capacity to adhere to skin and intestinal mucus of Senegalese sole, and their antagonistic effect against Photobacterium damselae subsp. piscicida, an important pathogen for farmed sole. The isolates from gilthead sea bream showed the highest percentage of adhesion to sole mucus, whilst the pathogenic microorganisms assayed and the isolates from sole showed, in general, a lower ability to adhere to sole mucus. The results suggest that the adhesion to fish mucus was more dependent on the isolate tested than on the host mucus. The isolates from gilthead sea bream also showed a higher antagonistic activity against P. damselae subsp. piscicida than those from Senegalese sole. Four isolates were selected, on the basis of their adhesive ability and antagonistic effect on P. damselae subsp. piscicida, to study their interactions with the pathogen in respect of adhesion to skin and intestinal mucus under exclusion, competition and displacement conditions. The results obtained show the ability of three isolates to reduce the adhesion of P. damselae subsp. piscicida to sole mucus under displacement and competition conditions. The adhesion of the pathogen to sole intestinal mucus was also significantly reduced when three isolates were assayed under exclusion conditions.

Animals↗
PubMed1982

The preservation of mucus and surface-associated microorganisms using acrolein vapour fixation.

Three fixation schedules were devised and compared in terms of their influence on the preservation of mucus and surface-associated microorganisms contained within it. Different mucus-secreting epithelial tissues from normal and spoiled oysters and normal rats were examined by scanning and transmission electron microscopy and light microscopy. On all tissues, mucus was best preserved in specimens fixed by 10% acrolein vapour for 1 h then immersed in 3% glutaraldehyde--3% formaldehyde fixative containing 0.05% ruthenium red, cacodylate buffer pH 7.4, for at least 3 h. This fixation schedule also greatly increased the preservation of microorganisms in mucus in specimens from spoiled oysters and normal rats. In contrast, the retention of mucus and surface-associated microorganisms was poor in tissues fixed either by 1% OsO4 vapour for 1 h followed by immersion in combined aldehyde fixative, or by direct immersion. The quality of preservation of the mucus layer, epithelium and sub-epithelium was also noted by transmission electron microscopy in tissues prepared by the different fixation schedules. Cellular preservation was satisfactory in directly immersed tissues but poor in vapour fixed specimens.

Acrolein↗
PubMed1994

Universal barrier to lateral spread of specific genes among microorganisms.

A genetic circuit to suppress the lateral spread of cloned genes from recombinant to indigenous microorganisms in the environment has been developed. It is based on the endonucleolytic activity of the bacterial toxin colicin E3, which has a distinct target at the 3' end of the 16S ribosomal RNA; this sequence is conserved in virtually all prokaryotic and many eukaryotic genera. Cleavage at this sequence separates the mRNA binding sites from the remainder of the 16S rRNA, thereby inhibiting protein synthesis. While host bacteria carrying the genes for both colicin production and colicin immunity are perfectly viable, lateral transfer of the E3 gene to non-immune recipients results in killing of such recipients. This genetic circuit decreases operational transfer frequencies of cloned genes linked to the E3 gene among a variety of bacterial genera by four to five orders of magnitude. In combination with transposon cloning vectors, the circuit is predicted to reduce the rate of lateral spread of specific genes to ecologically insignificant levels. This system therefore represents a useful tool both to explore the evolutionary and ecological consequences of experimentally reducing lateral gene spread among microorganisms, and to increase the ecological predictability of novel recombinant microorganisms.

Bacteria↗
PubMed1991

Preserving the motility of microorganisms.

This study focused on several factors that may influence the percentage of motile microorganisms in a sample from the tongue determined using a phase-contrast microscope. It was found that the time elapsing between sampling and analysis is crucially important. In both sterile saline and reduced transport fluid (RTF), a reduction of the percentage of motile microorganisms was found within 15-30 min after sampling respectively. In order to be able to prolong the time interval between sampling and analysis, it was found that storing a sample in a tuberculin syringe with RTF supplemented with Fildes extract preserved the motility of the microorganisms and gave no significant reduction in the percentage of motiles within 48 h.

Bacteriological Techniques↗