BACKGROUND: Viridans group streptococci (VGS) are being increasingly reported as pathogens causing septicemia in neutropenic and other immunocompromised patients since 1980s. In the past, VGS were nearly uniformly susceptible to beta-lactam antimicrobial agents, aminoglycosides, tetracyclines, and macrolides. Several recent published studies, however, indicate that antimicrobial resistance may be emerging as a problem with VGS. The purpose of this study was to determine the antimicrobial susceptibility of VGS strains isolated from blood cultures in recent period. METHODS: A total of 45 consecutive strains of VGS isolated from blood cultures between May 2001 and March 2002 at Wonju Christian Hospital were tested for antimicrobial susceptibility. Identification of VGS were performed by API Strep 32(bioMerieux sa, Marcy-l'Etoile, France) commercial kit. Antimicrobial susceptibility tests were done by NCCLS recommended disk diffusion method and penicillin MICs were determined by E test. RESULTS: Among the 45 VGS strains, frequently isolated organisms were Streptococcus mitis (31.1%), Streptococcus oralis (17.8%), Streptococcus constellatus (11.1%), and Streptococcus anginosus (8.9%). Overall intermediate-and resistant rates to antimicrobial agents of VGS were as follows: penicillin; 26.7% and 8.9%, erythromycin; 4.4% and 28.9%, clindamycin 2.2% and 22.2%, and ceftriaxone; 4.4% and 6.7%, respectively. Resistant rates of Streptococcus mitis and Streptococcus oralis were as follows: penicillin; 50% vs 50%, erythromycin 43% vs 37%, clindamycin 21% vs 37%, and ceftriaxone 7% vs 25%, respectively. CONCLUSIONS: These results indicate the species-related variability of susceptibility among VGS isolated from blood in recent period. In addition to S. mitis, S. oralis also displayed high rates of resistance to penicillin, macrolides, and ceftriaxone. The difference in susceptibilities between species of VGS indicates the importance of accurate identification and the need for continuing monitoring of antimicrobial resistance.
Aminoglycosides ; Anti-Infective Agents ; Ceftriaxone ; Clindamycin ; Diffusion ; Erythromycin ; Gangwon-do ; Immunocompromised Host ; Macrolides ; Penicillin Resistance ; Penicillins ; Sepsis ; Streptococcus anginosus ; Streptococcus constellatus ; Streptococcus mitis ; Streptococcus oralis ; Tetracyclines ; Viridans Streptococci*

Mitis group streptococci (MGS) were classified based on the nucleotide sequences 16S rRNA gene (16S rDNA) and comprised 13 Streptococcus species. However, 16S rDNA homogeneity among MGS was too high to discriminate between clinical strains at the species level, notably between Streptococcus mitis, Streptococcus oralis, Streptococcus pneumoniae, and Streptococcus pseudopneumoniae. The purpose of this study was to discriminate between 37 strains of MGS isolated from Korean oral cavities using phylogenetic analysis of the DNA-dependant RNA polymerase beta-subunit gene (rpoB). 16S rDNA and rpoB from clinical strains of MGS were sequenced using the dideoxy chain termination method and analyzed using MEGA version 5 software. The resulting phylogenetic data showed that the rpoB sequences could delineate clinical strains of MGS at the species level. Phylogenetic analysis of rpoB is therefore a useful approach for identifying MGS at the species level.
Base Sequence ; Discrimination (Psychology) ; DNA, Ribosomal ; DNA-Directed RNA Polymerases ; Genes, rRNA ; Streptococcus ; Streptococcus mitis ; Streptococcus oralis ; Streptococcus pneumoniae

OBJECTIVETo evaluate the effects of Yili dark bee propolis on the main cariogenic biofilm and mechanisms.

METHODSSusceptibilities to the ethanolic extract of propolis against Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Streptococcus sanguis (S. sanguis), Actinomyces viscosus (A. viscosus), and Actinomyces naeslundii (A. naeslundii) were analyzed by crystal violet stain method to determine the minimum biofilm eradication concentration (MBEC). The biofilm was initially cultivated for 24 h. Subsequently, the propolis groups with different concentration MBEC and initial pH 7.0 were cultured for 24 h. Moreover, the pH value was measured to evaluate the acid-producing ability of the tested plaque biofilm. The effects of propolis on the insoluble extracellular polysaccharide synthesis of S. mutans biofilm were evaluated by anthrone method.

RESULTSThe MBEC of Yili propolis on S. mutans, S. sobrinus, S. sanguis, A. viscosus, and A. naeslundii were 6.25, 1.56, 3.13, 0.78, and 0.78 mg.mL-1, respectively. Propolis could decrease the ΔpH of the tested plaque biofilm, and the differences between the control and propolis groups were statistically significant (P<0.05). At MBEC, propolis could reduce the ability of S. mutans in synthesizing insoluble extracellular polysaccharides.

CONCLUSIONYili propolis demonstrate remarkable eradicative effects on the cariogenic plaque biofilm, showing inhibition of the synthesis of biofilm-produced acids and insoluble extracellular polysaccharides.

Actinomyces viscosus ; Animals ; Bees ; Biofilms ; Dental Plaque ; Propolis ; Streptococcus mutans ; Streptococcus sanguis ; Streptococcus sobrinus

The authors observed the long term effects of chlorhexidine varnish treatment on microbial of dental plaque in orthodontic patients with fixed appliances. The initial sample was 100 patients who were arranged to be treated with fixed orthodontic appliances. The final sample consisted of 21 patients who could be traced for 32 weeks after application of fixed orthodontic appliances. They were classified into the experimental group (12 patients) and the control group (9 patients). The experimental group was treated with chlorhexidine varnish once a week for 4 weeks before application of fixed orthodontic appliance. The control group was not treated with chlorhexidine varnish before application of fixed orthodontic appliance. The experimental group was treated once more after 20 weeks. The microbial changes of dental plaque were analysed by indirect immunofluorescence technique at pre-treatment 4, 8, 20, and 32 weeks. The result were as follows. 1. In the experimental group, streptococcus mutans was significantly suppressed during experimental period. (p<0.01) But, in the control group, streptococcus mutans was significantly increased after placement of fixed orthodontic appliances during experiment period. (p<0.05) 2. Streptococcus sanguis, streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii did not show significant change between the experimental and the control group during experiment period.
Actinomyces ; Actinomyces viscosus ; Chlorhexidine* ; Dental Plaque* ; Fluorescent Antibody Technique, Indirect ; Humans ; Orthodontic Appliances ; Paint* ; Streptococcus mitis ; Streptococcus mutans ; Streptococcus sanguis

OBJECTIVETo investigate the antagonistic effects of three species of oral Streptococcus on the growth of oral Saccharomyces albicans in vitro.

METHODSDirect inoculation method, reverse inoculation method and mixed culture methods were respectively chosen to observe the changes of Saccharomyces albicans colony formation on the effects of Streptococcus mutans, Streptococcus sanguis and Streptococcus salivarius.

RESULTS1) No clear inhibition zone was observed in each of the groups by direct inoculation method. 2) Compared with the control groups, Saccharomyces albicans colony formation on soft agar of Streptococcus sanguis decreased significantly (P < 0.05). 3) Mixed culture method results showed that Streptococcus mutans could inhibit the growth of Saccharomyces albicans significantly at different time points (P = 0.001). 4) Under the action of bacteria culture supernatant, the count of Saccharomyces albicans in experiment groups showed statistical significance when compared with the control groups at 24, 48, 72 h (P = 0.001); The differences among the experimental groups were of no statistical significance at majority times (P > 0.05).

CONCLUSIONStreptococcus mutans, Streptococcus sanguis, and Streptococcus salivarius could obviously inhibit the growth of Saccharomyces albicans in vitro. However, it is still unclear that among which the inhibition effects is stronger. The antagonistic effects is weakened gradually.

In Vitro Techniques ; Saccharomyces ; Streptococcus ; Streptococcus mutans ; Streptococcus sanguis

Human mouth environment is known to include a variety bacteria, including Streptococcus spp., Staphylococcus spp., Actinomyces spp., Lactobacillus spp., Candida spp., Enterobacteriaceae, et al. Human oral microorganisms can cause dental caries, gingivitis, periodontitis, respiratory tract infection, and cardiovascular disease. Thus, right denture cleaning is essential to oral and general human health. The aim of this study was to evaluate the bactericidal effect of a sodium dichloroisocyanurate-based effervescent tablet (Aos Denti Germ, Aos Company, Chungbuk, Korea) against oral microorganisms. A total of 5 species Streptococcus spp. (Streptococcus anginosus, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, and Streptococcus sobrinus), Actinomyces oris, Candida albicans, and Escherichia coli were used in this study. All strains were exposed to the distilled water prepared with effervescent tablet. After the exposure, the mixture of strains and effervescent tablet was inoculated onto blood agar or MacConkey agar plate and cultured at 36℃. All strains were killed immediately on exposure to effervescent tablet. The results suggested that effervescent tablet could be used as an effective denture cleanser for dental hygiene.
Actinomyces ; Agar ; Bacteria ; Candida ; Candida albicans ; Cardiovascular Diseases ; Chungcheongbuk-do ; Dental Caries ; Denture Cleansers ; Dentures* ; Enterobacteriaceae ; Escherichia coli ; Gingivitis ; Humans ; Lactobacillus ; Mouth ; Oral Hygiene ; Periodontitis ; Respiratory Tract Infections ; Sodium ; Staphylococcus ; Streptococcus ; Streptococcus mitis ; Streptococcus mutans ; Streptococcus oralis ; Water

OBJECTIVETo observe the dynamic changes of oral microflora early colonized in infants.

METHODSThe oral swab samples for the study were taken in 1 day, 1, 3, 6, 9, 12 months after birth from 12 healthy neonates. By choosing suitable diluted concentration, the samples were incubated aerobically, facultative anaerobically and anaerobically. The strains were identified by observing colony characteristics, Gram staining and biochemical tests.

RESULTSS. salivarius was the most frequent microflora, followed by S. mitis, S. sanguis, S. gordonii and S. mutans occurred in oral cavity after tooth eruption. Veillonella spp. can be detected in oral cavity of 1-month-old babies, A. odontolyticus was isolated from 8.3% infants of more than 3 months old. L. acidophilus maintained the lower prevalence in oral cavity of babies. Leptotrichia buccalis and Capnocytophaga spp. occurred in oral cavity of some dentate infants.

CONCLUSIONS. solivarius and S. mitis are predominant species in oral cavity of the infants, Veillonella spp. is the first and the most anaerobic species appeared in oral cavity of healthy babies. A. odontolyticus is the first actinomyces detected in oral cavity. With the increasing months, kind and amount of microflora increase dramatically.

Actinomyces ; isolation & purification ; Colony Count, Microbial ; Female ; Humans ; Infant ; Infant, Newborn ; Longitudinal Studies ; Male ; Mouth ; microbiology ; Mouth Mucosa ; microbiology ; Saliva ; microbiology ; Streptococcus ; classification ; isolation & purification ; Streptococcus mitis ; isolation & purification ; Streptococcus mutans ; isolation & purification ; Streptococcus sanguis ; isolation & purification ; Veillonella ; isolation & purification

This study aimed to evaluate the antimicrobial effects of Acanthopanax sessiliflorum fruit (ASF; Ogaza) extracts on Streptococcus mutans and Streptococcus sobrinus, which are agents that cause dental caries, and on Streptococcus mitis and Streptococcus salivarius, the microbial flora of the oral cavity. The ASF extracts obtained using 70% ethanol were fractionated in the order of ethyl acetate and n-Butanol, concentrated under reduced pressure, and lyophilized to give powdery solvent extracts. The antimicrobial activity of ASF extracts from each solvent was examined using the disk diffusion method. As a result, only those extracts obtained using an ethyl acetate solvent showed antimicrobial activity. These extracts were selected, and the minimum inhibitory concentration was measured by disk diffusion method at various extract concentrations. Results showed a minimum inhibitory concentration of 32 mg/ml. The viable cell count was measured to confirm the minimum bactericidal concentration. Results showed a minimum bactericidal concentration of 64 mg/ml. In the cytotoxicity test using normal human dermal fibroblast cells, the absorbance value of the test group was similar to that of the control group at 0.64, 1.28, and 6.4 mg/ml. The bacteria and their colonies were examined using a scanning electron microscope. Boundaries between the antimicrobial activity region and non-antimicrobial activity region were observed around the paper disk, which was immersed in the extract with 32 mg/ml concentration. Bacterial colonization was not observed in the area with antimicrobial activity. This finding suggests that ASF extracts can inhibit the growth of some microorganisms in the oral cavity, in addition to the effects of these extracts known to date. In particular, ASF extracts may be used as a preparation for preventing dental caries by adding the extract to the toothpaste or oral mouthwash.
1-Butanol ; Bacteria* ; Cell Count ; Colon ; Dental Caries ; Diffusion ; Eleutherococcus* ; Ethanol ; Fibroblasts ; Fruit* ; Humans ; Methods ; Microbial Sensitivity Tests ; Mouth ; Streptococcus ; Streptococcus mitis ; Streptococcus mutans ; Streptococcus sobrinus ; Toothpastes

PURPOSE: Pneumonia is rather common and benign disease in children but its course is various. Many clinicians used the empirical antibiotics to treat pneumonia without identification of causative organism. This study was performed to find the pathogenic organism from the fluid culture by bronchoscopy with BAL (bronchoalveolar lavage) in severe pneumonia patients. METHODS: We studied 21 cases (male 15, female 6) who were admitted with severe pneumonia in the Department of Pediatrics, Sunlin Hospital from March to October in 1999. These patients had no underlying disease such as immunologic deficiency. We took laboratory tests including CBC, CRP, ESR, PB smear, mycoplasmal antibody and blood culture at admission day. We performed bronchoscopy with BAL, and wet smear and culture of that fluid. RESULTS: Organisms were cultured in nineteen cases out of 21 cases. Seven cases of Streptococcus mitis, five of Stenotrphomonas maltophilia, five cases of Streptococcus oralis, two of Moraxella species, two of Acinetobacter junii, one of Acinetobacter spesies, one Staphylococcus hominus, one alpha-h-Streptococcus, one Klebsiella pneumoniae, one Pseudomonas aeruginosa, one Enterobacter cloacae. Two organisms were cultured in nine cases. CONCLUSION: The positive rate of BALF culture was very high (90.5%). But, further studies are necessary for the patients with severe pneumonia preceded the use of antibiotics.
Acinetobacter ; Anti-Bacterial Agents ; Bronchoalveolar Lavage* ; Bronchoscopy ; Child ; Enterobacter cloacae ; Female ; Humans ; Klebsiella pneumoniae ; Moraxella ; Pediatrics ; Pneumonia* ; Pseudomonas aeruginosa ; Staphylococcus ; Streptococcus mitis ; Streptococcus oralis

OBJECTIVETo explore the feasibility of methyl thiazolyl tetrazolium (MTT) colorimetric method and the applied condition for the normal bacteria in the mouth, as Streptococcus mutans (S. mutans), Streptococcus sanguis (S. sanguis), Haemophilus actinomycetemcomitans (H. actinomycetemcomitans).

METHODSColony forming units (CFU) which was the standard antitheses was used to count bacteria. This study would gain some parameters by changing wavelength, reactive time, dosage and so on. MTT colorimetric method was applied in the counting of S. mutans, S. sanguis and H. actinomycetemcomitans.

RESULTSWhen counting S. mutans, the best wavelength was 510 nm, the best range was 1.5 x 10(5) - 1.0 x 10(7) CFU x mL(-1). When counting S. sanguis, the best wavelength was 545 nm, the best range was 1.5 x 10(5) - 2.0 x 10(7) CFU x mL(-1). When counting H. actinomycetemcomitans, the best wavelength was 557 nm, the best range was 1.0 x 10(6) - 5.0 x 10(7) CFU x mL(-1). MTT colorimetric method can be used for different aged S. mutans, S. sanguis and H. actinomycetemcomitans.

CONCLUSIONOral bacteria could be counted by MTT colorimetric method, which is fast and convenient.

Aggregatibacter actinomycetemcomitans ; Bacteria ; Humans ; Saliva ; Streptococcus mutans ; Streptococcus sanguis