PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Microbial Sensitivity Tests”

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 145 records · Page 8Linked to original sources
PubMed1997

Incorporation of antibacterial monomer MDPB into dentin primer.

The polymerizable monomer methacryloyloxydodecylpyridinium bromide (MDPB) shows antibacterial activity when immobilized in a resin-based material. In this study, the antibacterial effect of a dentin primer incorporating MDPB was investigated. The influence of incorporation of MDPB on bond strength to dentin and on the curing performance of the adhesive system was also evaluated. Experimental primers were prepared by addition of MDPB into a proprietary primer at 1, 2, or 5%. Antibacterial effects of experimental primers were compared with those of control primer and two other proprietary primers by an agar disc-diffusion method and bactericidal activity test. Experimental primers produced greater inhibition zones against Streptococcus mutans, Actinomyces viscosus, and Lactobacillus casei than any of three proprietary primers, and inhibition increased as the concentration of MDPB was increased. Bactericidal activity of MDPB-containing primers against Streptococcus mutans was greater than those of the other three primers, with incorporation of MDPB at 5% showing complete killing of bacteria after 30 s contact. No decrease in tensile bond strength was observed for materials containing MDPB. On the contrary, the primer incorporating 1 and 2% MDPB showed higher bond strength than all the others, including the control (p < 0.05). When the degree of conversion of the complex of primer and adhesive resin was determined with Fourier Transform Infrared Spectroscopy, there were no significant differences between any of the experimental primers and the control (p > 0.05). These results indicate that incorporation of the antibacterial monomer MDPB enhanced the antibacterial effect of a proprietary dentin primer before curing, and had no adverse influence on bond strength to dentin and curing of the adhesive system.

Actinomyces viscosus↗
PubMed2003

Inhibition of the transcription of the Escherichia coli O157:H7 genes coding for shiga-like toxins and intimin, and its potential use in the treatment of human infection with the bacterium.

Reverse-transcription PCR (RT-PCR) was used to assess the effects, in vitro, of rifampicin on the transcription of the eaeA, stx1 and stx2 genes (coding for intimin and shiga-like toxins I and II, respectively) of seven strains of Escherichia coli O157:H7 associated with human infection. Each strain was found to possess all three genes and, in the absence of rifampicin, all seven strains transcribed eaeA and stx2 (three strains did not transcribe their stx1 genes). Transcription of all three genes was inhibited (as witnessed by a negative result in the RT-PCR), however, when the strains were incubated, at 37 degrees C, with rifampicin at 4 microg/ml (found to be the minimum concentration of this antimicrobial agent that inhibited the multiplication of E. coli O157:H7). The results of an assay based on reversed passive latex agglutination (RPLA) revealed that exposure of the bacteria to 4 microg rifampicin/ml led to a 12-fold decrease in the release of shiga-like toxin I and a 16-fold decrease in the release of shiga-like toxin II. As rifampicin is capable of inhibiting the in-vitro transcription of the genes encoding the shiga-like toxins and intimin attachment protein of E. coli O157:H7, it may be useful in the treatment of human infections with strains of this bacterium. Studies are now underway to assess the in-vitro and in-vivo effects of rifampicin, at both transcription-inhibitory and bactericidal concentrations, on E. coli O157:H7. The effects of other agents on the inhibition of the expression or activity of the shiga-like toxins and intimin attachment protein will also be determined.

Adhesins, Bacterial↗
PubMed2006

Survey and properties of Staphylococcus aureus isolated from Japanese-style desserts.

We surveyed the contamination of 315 Japanese- and western-style desserts and 247 human hands by Staphylococcus aureus and other staphylococcal bacteria. The most frequently isolated staphylococcal bacterium was S. warneri, followed by S. aureus. Only 1.9% of western-style desserts were contaminated by S. aureus strains, while 19.4% and 13.0% of Japanese-style desserts and human hands respectively were contaminated. Ninety-four isolates of S. aureus were characterized as to their biological properties and enterotoxigenicity. Although staphylococcal enterotoxins (SEs) were detected by enzyme-linked immunosorbent assay in the cultured broth of all S. aureus isolates, the reversed passive latex agglutination method and the polymerase chain reaction showed only 39 (41.5%) and 40 (42.6%) samples respectively as SE-positive. The predominant type of SE was SEB (67.5%), and eight strains produced SEA. None of the S. aureus strains had penicillin-binding protein 2', showing that methicillin-resistant S. aureus was not present in the samples.

Anti-Bacterial Agents↗
PubMed2004

Control of microorganisms in vitro by endodontic irrigants.

The aim of this study was to determine the minimum inhibitory concentration (MIC) and antimicrobial effectiveness by the direct exposure test of 4 endodontic irrigants [1% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX), 1% calcium hydroxide (Ca(OH)2; prepared with 1 g of Ca(OH)2 and 100 mL of sterile distilled water), a solution of Ca(OH)2 + detergent (HCT20)] for S. aureus, E. faecalis, P. aeruginosa, B. subtilis, C. albicans and a mixed culture. Microbial growth was analyzed by two methods: turbidity of the culture medium that was confirmed by Gram stain and subculture in a specific nutrient broth. In the dilution test, NaOCl solution showed MIC equal to 0.1% for S. aureus, E. faecalis, P. aeruginosa and C. albicans and equal to 1% for B. subtilis and the mixed culture. CHX (2%) presented MIC equal to 0.000002% for S. aureus, 0.02% for E. faecalis, B. subtilis, C. albicans and the mixed culture and 0.002% for P. aeruginosa. Ca(OH)2 solution (1%) showed MIC greater than 1% for all the microorganisms except P. aeruginosa for which it was equal to 1%. Calcium hydroxide solution + detergent showed MIC equal to 4.5 mL for S. aureus, P. aeruginosa, B. subtilis, C. albicans and the mixed culture and greater than 4.5 mL for E. faecalis. In the direct exposure test, NaOCl had better antimicrobial effectiveness for all microorganisms at all times. CHX (2%) was effective for S. aureus, E. faecalis and C. albicans at all times, and ineffective for P. aeruginosa, B. subtilis and the mixed culture. The other solutions showed the worst results.

Anti-Infective Agents, Local↗
PubMed2006

In vitro evaluation of the susceptibility of endodontic pathogens to calcium hydroxide combined with different vehicles.

The aim of this study was to investigate in vitro the antimicrobial activity of calcium hydroxide [Ca(OH)2] in combination with different vehicles against endodontic pathogens. For such purpose, a broth dilution test was performed. Pastes were prepared with Ca(OH)2 powder and the following vehicles: sterile water, glycerin, camphorated monochlorophenol (CMCP), CMCP + glycerin, polyethyleneglycol and CMCP + polyethyleneglycol. The time required for the pastes to produce negative cultures against the tested microorganisms was recorded and analyzed statistically using the Kruskal Wallis test at 5% significance level. Timing for pastes to eliminate the aerobic and facultative anaerobic microorganisms ranged from 6 to 24 h, while strict anaerobic microorganisms were inhibited within 30 s to 5 min. Microbial susceptibility, ranked from weakest to strongest, can be presented as follows: Enterococcus faecalis (the most resistant microorganism), Candida albicans, Staphylococcus aureus, Porphyromonas gingivalis, Porphyromonas endodontalis and Prevotella intermedia (the last two microorganisms required the same time to be eliminated). In conclusion, calcium hydroxide pastes needed more time to eliminate facultative than anaerobic microorganisms. These findings suggest that the antimicrobial property is related both to paste formulation and to microbial susceptibility.

Anti-Bacterial Agents↗
PubMed1998

Correlation between ability of Ornithobacterium rhinotracheale to agglutinate red blood cells and susceptibility to fosfomycin.

Twenty five freeze-dried isolates of Ornithobacterium rhinotracheale were used for the determination of minimum inhibitory concentrations (MIC) against the antibiotic fosfomycin (Fosbac, produced by Bedson SA, consisting of a 25% mixture of fosfomycin). The same isolates were tested for their ability to haemagglutinate chicken red blood cells. Ten of the 25 isolates were found to be susceptible to fosfomycin (MIC values below 128 ug/ml). All of these isolates were able to agglutinate red blood cells. This is the first report on the ability of O. rhinotracheale to agglutinate red blood cells. The remaining 15 isolates were resistant to fosfomycin (MIC values above 128 ug/ml). Only five of these isolates were found to have the ability to agglutinate red blood cells. There appears to be a correlation between the ability of O. rhinotracheale isolates to agglutinate red blood cells and their susceptibility to fosfomycin. The ability of certain isolates of O. rhinotracheale to agglutinate red blood cells, raises the questions of differences in virulence between the isolates which can agglutinate red blood cells and those which cannot and the use of this ability to agglutinate red blood cells as an alternative method for serotyping O. rhinotracheale.

Animals↗
PubMed1999

Antimicrobial properties of copper-coated electroconductive polyester fibers.

Three synthetic copper-coated EURO-static fibers (PET--polyester, PA--polyamide, and PAC--polyacrylamide) manufactured by EUROPA Corporation S.C., Poland, were tested as potential antimicrobial agents. The inhibitory properties of the fibers were examined using different microorganisms as follows: i. Staphylococcus aureus ATCC 25293, and Pseudomonas aeruginosa ATCC 27853 reference strains, ii. 8 strains of S. aureus (4 MRSA and 4 MSSA) and 5 strains of P. aeruginosa isolated from infected wounds, and iii. fungal pathogen Scopulariopsis sp. isolated from onychomycosis case. The results of experiments have evidenced that polyester (PET) copper-coated EURO-static fibers inhibit the growth of all the strains used.

Antisepsis↗
PubMed2000

Iodinated natural rubber latex: preparation, characterisation & antibacterial activity assessment.

Natural Rubber (NR) in both its latex and dried form was treated with iodine to make it antibacterial in nature. The NR latex was dried and washed, dissolved in toluene, iodinated and cast into films. In a different approach, NR in its latex form (emulsion) was blended with aqueous solution of povidone-iodine complex (PVP-I) and films were cast. Phase separation of PVP-I was observed in the films prepared using NR latex; whereas the film prepared using NR solution in toluene and molecular iodine were homogeneous, transparent light brown. Solubility assessment of the films revealed that unlike pure NR, the iodinated NR failed to go into solution completely. The films obtained from both the approaches were evaluated for release of iodide ions. On immersion in water, PVP-I blended latex did not retain iodine while sustained release of iodide ion was observed in case of dried NR dissolved in toluene and treated with iodine. The FT-IR spectra of the iodinated films revealed that iodine attaches covalently to the double bonds in the isoprene units of NR. The films were also evaluated for their antibacterial properties and it was observed that the films prepared from both the approaches, acquired antimicrobial properties.

Anti-Bacterial Agents↗
PubMed2004

Glutaraldehyde in bonding systems disinfects dentin in vitro.

PURPOSE: To study the dentin disinfecting capacity of glutaraldehyde-containing bonding agents. MATERIALS AND METHODS: Uniformly sized bovine dentin blocks infected with Enterococcus faecalis ATCC 29212 were treated according to manufacturer's instructions with a three-step bonding system (Syntac Classic), its single components, or Gluma Primer. Bacterial growth from dentinal filings obtained immediately after application of the bonding agents was assessed at different dentin depths. Minimal inhibitory concentration and minimal bactericidal concentration of glutaraldehyde against E. faecalis were determined. RESULTS: Both Gluma Primer and Syntac Adhesive disinfected dentin, while the other components failed to do so. This was explained by the high antibacterial efficacy of glutaraldehyde even at low concentrations. Applied in consecutive order, the Syntac bonding system disinfected dentin blocks equally well with or without previous application of Gluma Primer. CONCLUSION: Under the conditions of the current study, bonding agents containing glutaraldehyde appear to be good dentin disinfectants compatible with bonding systems. However, their effect on pulp tissue awaits further clarification.

Animals↗
PubMed2001

[Resistance of Mycobacterium fortuitum against varied physical factors and its survival in different surroundings].

OBJECTIVE: To observe the resistance of Mycobacterium fortuitum against some physical factors and its survival in different surroundings. METHODS: Bacterium solution of Mycobacterium fortuitum was added to the carriers, then it was treated in different interval of time and physical surroundings (high temperature, maximum pressure in ultraviolet ray, dry, sunshine). The treated specimen was cultured to observe the resistance of Mycobacterium fortuitum against physical factors. At the same time, some of bacterium solution were mixed into materials in different surroundings (water, wet soil, and dry soil). The specimen was cultured constantly in different time under the room temperature to observe the growth of Mycobacterium fortuitum in different surroundings. RESULTS: Mycobacterium fortuitum was killed at 60 degrees C in 135 minutes, 80 degrees C in 60 minutes, 100 degrees C in 5 minutes, and high pressure in 5 minutes (6.8 kg at 121 degrees C, 4.5 kg at 115 degrees C). It can also be killed under hot sunshine in one hour and under the ultraviolet ray at 105.5 microW/cm. Mycobacterium fortuitum can exist in water over 27 months, in wet and dry soil and in dry surroundings for more than one and a half year. With the extending of time, quantities of Mycobacterium fortuitum showed a trend of decline. CONCLUSIONS: Mycobacterium fortuitum possesses low resistance against high temperature, but higher resistance against ultraviolet ray. The germ shows stronger endurance in different surroundings and can exist for a long time.

Environment↗
PubMed2005

The prevalence and molecular typing of enterotoxigenic Escherichia coli strains isolated from diarrheic stools in Malatya, Turkey.

This study was performed from June 2002 to November 2003 year in Malatya, eastern Turkey. Stools of 172 diarrheic patients and 90 healthy controls were analysed for enterotoxigenic Escherichia coli (ETEC). Heat-labile (LT) and heat-stable (ST) toxins were investigated by passive latex agglutination and enzyme immunoassay, respectively. Nine ETEC strains were isolated from 172 diarrheic stools (5.2%). Seven of the ETEC strains (10.1%) were isolated from 69 children in the 0-5 year age group. Two of these pediatric isolates were ST positive (2.9%) and five were LT positive (7.2%). ETEC was not isolated in the 6-18 year age group. Two ST producing E. coli strains were detected in diarrheic adult patients (> 18 years). In the 90 controls, two ETEC strains were detected (2.2%). One of them was a LT producer (1.1%) and the other was a ST producer (1.1%). E. coli strains producing both toxins simultaneously were not observed. ETEC positivity was higher in the diarrheic group than in the control group but statistically not significant (p > 0.05). The rate of resistance among ETEC strains to cefuroxime axetil, ampicillin, piperacillin, and trimethoprim-sulfamethoxazole was 72.7%, 54.5%, 45.5%, and 36.4%, respectively whereas the resistance rate to the same antibiotics in non-ETEC strains was 14%, 62%, 54%, and 66%, respectively. All ETEC isolates were intermediately resistant to cephalothin and fully susceptible to other antibiotics tested. Typing of the ETEC strains was done by arbitrary primed polymerase chain reaction (AP-PCR). Only two LT strains of the 11 typed strains had a unique profile. The remaining nine were mixed LT and ST strains and divided into two groups. The first group had three strains having a similarity coefficient ranging from 70-90%. The other one had six strains, five of them were similar and one was subtype isolate. It can be concluded that ETEC strains might be considerably important enteropathogens especially in pediatric patients in the 0-5 year age group. High clonal relation indicated that ETEC strains were epidemiologically related.

Adolescent↗
PubMed2005

In vitro evaluation of antibacterial activities of root canal sealers.

OBJECTIVE: The purpose of this study was to compare the antimicrobial effect of AH-26 (a resin-based sealer), Dorifill (a ZOE-based sealer), and pure ZOE after 24 hours and after one week. METHODOLOGY: All sealers were prepared according to the manufacturers' directions immediately before testing. The micro-organisms used in this assay included Staphylococcus aureous and Streptococcus mutans, which were prepared from isolated species in the microbiology laboratory. The antimicrobial effects of each sealer were determined by measuring the diameter of the zone of inhibition in millimeters after incubation at 37 degrees C for 24 hours and seven days in a humid atmosphere. Each test was repeated three times. RESULTS: In the 24-hour samples, the antibacterial activity of AH-26 was significantly greater than two other materials tested on both bacteria (p < 0.05). The antibacterial activity of Dorifill and ZOE on S. aureous was not significantly different from each other (p > 0.05), but Dorifill had a significantly greater effect on S. mutans than ZOE (p < 0.05). In the seven-day samples, statistically significant zones of bacterial growth inhibition for both bacterial species tested were observed in descending order of antibacterial activity as ZOE > AH-26 > Dorifill (p < 0.05). CONCLUSION: The products studied exhibited some variable antibacterial properties. In 24 hours, the AH-26 exerted the greatest activity against both organisms tested. By seven days, the ZOE-based sealer-Dorifill-showed lower antibacterial activity than AH-26 and pure ZOE.

Anti-Bacterial Agents↗
PubMed2005

A modified mycological medium for isolation and culture of Malassezia furfur.

A mycological medium was developed for primary isolation and culture of lipophilic yeasts. It was initially based on published information of nutrients and trace components that would promote the growth of these yeasts. It was subsequently modified and adjusted to specifically promote the growth of lipophilic yeasts and simultaneously avoid the luxurious growth of other fungi and bacteria. With this medium, the conventional bacteriological procedures such as microbial streaking for pure culture and anti-microbial sensitivity testing could be carried out for these lipophilic yeasts.

Agar↗
PubMed1991

[Biocompatibility studies of periodontal dressings].

Periodontal packs have to be considered medications due to their direct contact to the gums and wound surfaces. For this reason a high cell biological compatibility has to be considered as one of their most important properties. For this reason, the cytotoxicity of all periodontal packs commonly used in Germany was examined, using the "Erlangen Ciliate Test". This method, which is commonly used to determine the cytotoxic and cytostatic properties of a wide variety of different materials and substances, is based on liquid cultures of the eucaryotic organism "Tetrahymena piriformis", using an excellent correlation with mammalian or human tissue cultures as well as the LD50. A significant toxicity of up to 50% could be shown in all but one periodontal pack. In addition, the antibacterial properties of the same materials were examined, using liquid cultures of Staphylococcus aureus and hemolyzing streptococci group A. However, using this method, no significant antibacterial effects could be shown.

Animals↗