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PubMed1977

Effect of a Ca(OH)2 solution and a chlorhexidine based detergent on the microbial activity of human carious teeth.

Occlusar carious lesions from human molars, preserved in continuous humidity after extraction, were removed using conventional clinical techniques. Bacteriological samples were taken after rinsing the cavity with water only, after experimentally infecting the cavity and after treating uninfected cavities either with a saturated Ca(OH)2 solution or with a chlorhexidine based detergent. The samples were cultivated on blood agar plates aerobically and anaerobically. Cavities rinsed with water only showed very sparce bacterial growth. After experimental infection the growth was significant, but decreased radically after treatment with the test materials. In order to describe the effect of the two test materials on the microbial enzyme activity in infected dentin, cryostat sections of 10 micrometer were prepared from undermineralized carious dentin fragments excavated from freshly extracted human teeth. Conventional histochemical techniques were applied to demonstrate the aminopeptidase activity in the sections using N-L-leucyl-2-naphthylamide as a substrate. The aminopeptidase activity of carious dentin was inhibited totally with the Ca(OH)2 solution, whereas the chlorhexidine based detergent had no effect on the enzyme activity.

Aminopeptidases↗
PubMed1976

Kinetics of the actions of tetracyclines on Escherichia coli as studied by microcalorimetry.

Microcalorimetry was used to study the kinetics of the actions of various tetracyclines on a strain of Escherichia coli. Differences in the capacity to suppress the metabolism of this bacterium were observed. When the antibiotic was present from the start of the experiment, a heat production of 2.0 muW/ml was registered after 12.5 h using minocycline; the corresponding figures for doxycycline, oxytetracycline, and tetracycline were 7.3, 6.6, and 4.5 h, respectively. In these experiments, equal concentrations, i.e., half the minimum inhibitory concentration (MIC), of each drug were used. The MIC for all the tetracyclines tested, determined by the broth dilution technique, was 0.8 mug/ml. In other experiments, the antibiotic (concentration, 1.6 mug/ml = 2x MIC) was introduced into the growth vessel during the logarithmic growth phase of the organism. The extent and duration of the inhibitory effect on the metabolism, as judged from the decrease in heat production, varied with the different tetracyclines. Immediately after introduction, minocycline, doxycycline, oxytetracycline, and tetracycline decreased the heat production in decreasing order of potency. With tetracycline, the heat production rose after about 1 h, and with minocycline it rose after about 9 h. The heat production remained at a low level for at least 19 h when using doxycycline and oxytetracycline. The results indicate that microcalorimetry offers a means for studies of the kinetics of the antibacterial actions of antibiotics and provides information that cannot be obtained by conventional bacteriological techniques. This information may be of use, in conjunction with pharmacokinetic data, in establishing optimum doses and dose intervals in antibiotic therapy.

Calorimetry↗
PubMed1985

Bacteriology and ultrastructure of the bladder in patients with urinary tract infections.

Tissue obtained by biopsy of the bladder from 33 patients with various urinary tract symptoms was studied by conventional bacteriological techniques and by scanning electron microscopy (SEM). All the patients had recurrent urinary tract symptoms which had not completely responded to antibiotic therapy. Eleven of the patients had greater than or equal to 10(8) colony-forming units (CFU) of bacteria/1 urine; six had between 10(6) and 10(7) CFU/1, and 16 were abacteruric. Bacteria were isolated, however, from the tissue obtained by biopsy from eight of the 16 patients with sterile urine and bacteria were seen on the uro-epithelium in 14 of these patients. By comparison, in all samples of tissue obtained from the 11 patients with greater than or equal to 10(8) CFU/1 of urine bacteria were seen on the uro-epithelium and from nine of these, bacteria were subsequently grown. Fastidious organisms were not isolated from any of the patients. The uro-epithelium of all those studied was also shown to be grossly disrupted with increased disturbance and loss of the epithelial cells when compared with tissue obtained from uninfected patients. The degree of uro-epithelial disturbance was greatest in patients with histories of urinary tract infections lasting more than 4 months. The findings suggest that bacteriological examination of the urine does not always reflect bacterial infection on the bladder surface nor disruption of the uro-epithelium. The changes on the bladder surface may explain the patients' symptoms. In view of the results, a scheme is proposed that explains the development of symptoms in patients with urinary tract and bladder infections.

Adult↗
PubMed1996

Empirical or culture-guided therapy for microbial keratitis? A plea for data.

In the United States, about 30,000 bacterial corneal ulcers are treated annually. Compared with 100, or even 20, years ago ophthalmologists today have available to them many diagnostic tools (including special media and bacterial identification techniques), and in impressive assortment of antibiotics. Many reviews and book chapters describe the uses of microbiologic studies--from Gram and Giemsa staining to media inoculation to immunofluorescence and even molecular genetics--to identify causative organisms. This literature also describes the formulas for preparation of highly concentrated, "fortified" antibiotics for initial treatment of bacterial keratitis, until culture and sensitivity results are available to guide modifications in therapy. It would seem, therefore, that "experts" in the field of corneal and external diseases have reached consensus on an appropriate initial microbiologic evaluation and treatment of suspected microbial keratitis, and the large body of literature on this topic might be considered to represent practice guidelines. It comes as a surprise to many that these published "guidelines" apparently are routinely ignored in current clinical practice.

Anti-Bacterial Agents↗
PubMed1982

Nasal obstruction. Adenoiditis vs adenoid hypertrophy.

The terms "adenoiditis" and "adenoid hyperplasia" are often used interchangeably to describe posterior nasal obstruction in children, tending to obscure indications for adenoidectomy. To more clearly define the role of the adenoid bed in nasal obstruction and its relationship to aural disease, we examined tissue obtained at adenoidectomy from 22 children via the quantitative bacteriological technique. In three patients, adenoidectomy was performed for nasal obstruction alone, in nine patients for serous otitis media and nasal obstruction, and in ten patients for nasal obstruction with serous otitis media and recurrent bacterial otitis. Using the criteria that 10(5) bacteria per gram of tissue indicates infection, 90% of the patients in the last group had infected adenoids vs 8% of the patients in the first two groups. Quantitative immunoglobulin levels, WBC counts, or preoperative antibiotic therapy was not helpful in determining which patients had infected adenoids. Pressure-equalizing tubes were placed when appropriate. A follow-up of nine to 22 months is included.

Adenoidectomy↗
PubMed1995

Evaluation of a rapid agglutination test for detection of group B streptococci in the gastric aspirates of neonates.

A rapid commercial agglutination test (Bactigen Strepto B) for detection of group B streptococci in gastric aspirates of neonates was evaluated. One hundred and sixty-one gastric samples were analyzed with conventional bacteriological techniques and with the commercial test after modification of the extraction technique. The sensitivity of the test relative to the culture technique was 90.4%, the specificity 94.2%, the positive predictive value 70.3% and the negative predictive value 98.5%. The commercial test could be performed in one hour and showed good sensitivity and specificity. If a test result was negative colonization could be excluded, obviating the need for empirical antibiotic therapy, whereas a positive result suggested colonization or neonatal infection with group B streptococci.

Agglutination Tests↗
PubMed1994

Evaluation of a semi-automated 24-hour commercial system for identification of Enterobacteriaceae and other gram-negative bacteria.

A semi-automated commercial system (ID 32 E, bioMérieux) for 24-hour identification of Enterobacteriaceae and other gram-negative fermentative and nonfermentative bacteria encountered in diagnostic microbiology was evaluated. Overall, the system correctly identified 506 (91.5%) of the 553 strains tested, 94 (17.0%) strains requiring additional tests for complete identification. Six (1.1%) strains were misidentified and 33 (6.0%) strains were not identified. Eight (1.4%) strains were not present in the database and were misidentified or not identified. The system is a suitable alternative to existing systems for the identification of Enterobacteriaceae and other gram-negative bacteria frequently encountered in clinical samples.

Bacterial Typing Techniques↗
PubMed1990

A tubular bioreactor for high density cultivation of microorganisms.

By simulating the functions of the animal intestine, the authors have developed a novel tubular bioreactor (TBR) which is capable of containing both the reaction and separation of products in a single system. This reactor consisted of inorganic ultra filtration membrane modules in the primary part of the system, a heat exchanger and a recycling pump. The operation characteristics of the TBR were studied by cultivating Lactobacillus casei at a laboratory scale. The cell density obtained was up to 10 times higher than the density obtained by using the conventional jar fermentor. Furthermore, 40 g l-1 of cell mass was obtained in only 14 hours with 20 l of fresh medium when the dilution rate was increased according to the cellular growth. Afterwards, the cultivation time and the volume of fresh medium were reduced to 44% and 74%, respectively, of the values in the cultivation operation at constant dilution rate.

Bacteriological Techniques↗
PubMed1999

Catheter-related bloodstream infections.

Catheter-related bloodstream infections (CBIs) rank among the most frequent and potentially lethal nosocomial infections. Intravascular devices become contaminated on the outer surface during nonaseptic insertion or maintenance of the catheter exit site or endoluminally during hub manipulation. CBI is heralded by spiking fever, malaise and rigors and should be promptly diagnosed to prevent endocarditis and septic metastasis. In about two-thirds of the cases the offending organisms are coagulase-negative staphylococci; Staphylococcus aureus, gram-negative bacilli, and Candida sp. are responsible for one-third of these infections and carry a worse prognosis. Diagnosis of CBI relies on proper bacteriologic techniques, some of which can be performed in situ avoiding withdrawal of the device. Prevention strategies should aim at avoiding extra- and endoluminal contamination and should be based on three main pillars: maximal aseptic barriers at insertion, appropriate site maintenance, and junctional (hub) care and protection. Treatment includes catheter withdrawal and appropriate antibiotic coverage. For long-term cuffed catheters, local treatment with intraluminal administration of antibiotics is effective and can save a significant number of catheters, particularly those colonized by coagulase-negative staphylococci.

Antibiotic Prophylaxis↗
PubMed2002

Heterotrophic bacteria growing in association with Methylococcus capsulatus (Bath) in a single cell protein production process.

The methanotrophic bacterium Methylococcus capsulatus (Bath) grows on pure methane. However, in a single cell protein production process using natural gas as methane source, a bacterial consortium is necessary to support growth over longer periods in continuous cultures. In different bioreactors of Norferm Danmark A/S, three bacteria consistently invaded M. capsulatus cultures growing under semi-sterile conditions in continuous culture. These bacteria have now been identified as a not yet described member of the Aneurinibacillus group, a Brevibacillus agri strain, and an acetate-oxidiser of the genus Ralstonia. The physiological roles of these bacteria in the bioreactor culture growing on natural, non-pure methane gas are discussed. The heterotrophic bacteria do not have the genetic capability to produce either the haemolytic enterotoxin complex HBL or non-haemolytic enterotoxin.

Bacillus↗
PubMed2001

Numerical taxonomy of microorganisms isolated from goat cheese made in Chile.

118 strains of heterotrophic microorganisms were isolated from goat cheese produced domestically in the IV Region of Northern Chile (Serene, Ovalle, and Illapel) and sold in supermarkets in Valparaíso, Chile. The results of 89 phenotypic tests were numerically analyzed against 17 reference strains, using the simple matching coefficient (S(SM)). Thirteen phena were found at a 78% similarity level. Five of them (A, B, C, D, and E) were assigned to the family Enterobacteriaceae, phenon F was identified as belonging to the genus Aeromonas and strains of phenon G were assigned to the genus Acinetobacter. The other phena were identified as being members of the genera Bacillus (H, I, and J), Staphylococcus (K), Enterococcus (L), and Micrococcus (M). Approximately 19% of the isolates were Escherichia coli and 27%, Staphylococcus aureus.

Animals↗
PubMed2002

Differences between reference laboratories of the European community in their ability to detect Salmonella species.

The ability of national reference laboratories for Salmonella of the European Union member states to detect Salmonella bacteria was tested in four collaborative studies during the period 1995 through 1999. Three different methods were prescribed in the four studies. Capsules containing various numbers of Salmonella Typhimurium or Salmonella Enteritidis were tested. In studies II, III and IV, Salmonella bacteria were isolated in the presence of competitive microorganisms. Significant differences were found between the four studies due to varying levels of difficulty with regard to the level of contamination, the use of serotypes and the presence of competitive organisms. There were also significant differences between the laboratories in the results obtained. Possible reasons for these differences will be further investigated by the European Union Community Reference Laboratory for Salmonella.

Bacterial Typing Techniques↗
PubMed2005

Isolation of Vagococcus salmoninarum in rainbow trout, Oncorhynchus mykiss (Walbaum), broodstocks: characterization of the pathogen.

Coldwater 'streptococcosis', caused by Vagococcus salmoninarum, is an emerging disease of rainbow trout in the European Union, causing mortality rates up to 50% in broodstock during the spawning period, with water temperature of 10-12 degrees C. A study to determine the presence and role of this bacterium was undertaken using classical bacteriological techniques confirmed with polymerase chain reaction. This is the first report of isolation of V salmoninarum in relation to outbreaks of mortality in a rainbow trout farm devoted exclusively to broodstock rearing in Spain. A total of 10 isolates of V salmoninarum were characterized by their morphological, cultural, physiological, biochemical and enzymatic traits. Some differences were observed in parameters such as growth on MacConkey agar, H2S production, acid production from starch, and some other minor variations. Isolates were sensitive to erythromycin and oxytetracycline tested in vitro, but treatments conducted in the field were ineffective. An attempt at vaccination did not provide encouraging results.

Animals↗