scholarly journals Cotrimoxazole Prophylaxis Specifically Selects for Cotrimoxazole Resistance inStreptococcus mutansandStreptococcus sobrinuswith Varied Polymorphisms in the Target GenesfolAandfolP

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Buwembo William ◽  
Charles Mugisha Rwenyonyi ◽  
Göte Swedberg ◽  
Fred Kironde
Keyword(s):  
Mutans Streptococci ◽  
Streptococcus Sobrinus ◽  
Genetic Transfer ◽  
Cotrimoxazole Prophylaxis ◽  
Sulfonamide Drug ◽  
Prophylaxis Group ◽  
Folate Pathway ◽  
Reference Sequences ◽  
Selection Of

The selection of antibiotic resistance by cotrimoxazole prophylaxis was evaluated, and we characterized the mechanism of cotrimoxazole resistance inStreptococcus mutansandStreptococcus sobrinus.In vitrosusceptibility to six antibiotics was evaluated on 64 mutans streptococci group (MSG) isolates from a cotrimoxazole prophylaxis group and compared to 84 MSG isolates from a nonprophylaxis group. ThefolAandfolPgenes were sequenced and compared with reference sequences at NCBI. Only resistance to cotrimoxazole was significantly higher in the prophylaxis group (54.7% versus 15.5%,OR=6.59, 95% CI: 2.89–15.3,P<0.05). Resistance to amoxicillin, ceftriaxone, chloramphenicol, erythromycin, and tetracycline was 1.4%, 25.5%, 6.2%, 6.5%, and 29.6% of the isolates, respectively. Considerable polymorphisms were found in thefolPgene inS. mutans, but this could not be linked to sulfonamide drug resistance. No variation was seen infolPorfolAgenes ofS. sobrinus. Genetic transfer of folate pathway genes seems unlikely in these isolates.

scholarly journals Comparison of the Efficacies of Oral β-Lactams in Selection of Haemophilus influenzae Transformants with Mutated ftsI Genes

2008 ◽  
Vol 52 (5) ◽  
pp. 1880-1883 ◽  
Author(s):  
Sho Takahata ◽  
Yoshihisa Kato ◽  
Yumiko Sanbongi ◽  
Kazunori Maebashi ◽  
Takashi Ida
Keyword(s):  
Haemophilus Influenzae ◽  
Horizontal Transfer ◽  
Susceptible Strain ◽  
Genetic Transfer ◽  
Selection Window ◽  
Selection Of

ABSTRACT Horizontal transfer of the mutated ftsI gene from β-lactamase-nonproducing ampicillin-resistant (BLNAR) Haemophilus influenzae to a susceptible strain was examined in vitro under selection with nine oral β-lactams (ampicillin, amoxicillin, cefprozil, cefuroxime, cefpodoxime, cefdinir, cefcapene, cefditoren, and tebipenem). Compared to the penicillins and the carbapenem, the cephalosporins showed a wide selection window for the genetic transfer.

In vitro Demineralization of Enamel by F-sensitive and F-resistant Mutans Streptococci in the Presence of 0, 0.05, or 0.5 mmol/L NaF

1991 ◽  
Vol 70 (12) ◽  
pp. 1491-1496 ◽  
Author(s):  
C. Van Loveren ◽  
L.M. Spitz ◽  
J.F. Buijs ◽  
J.M. Ten Cate ◽  
A.D. Eisenberg
Keyword(s):  
Human Subjects ◽  
Lactate Production ◽  
Calcium Content ◽  
Mutans Streptococci ◽  
High Dose ◽  
Streptococcus Sobrinus ◽  
Demineralized Enamel ◽  
A Cell ◽  
Bovine Enamel

Lactate production and accompanying enamel demineralization by fluoride-sensitive and fluoride-resistant mutans streptococci were studied in an in vitro demineralization model in the presence of 0, 0.05, or 0.5 mmol/L NaF. The fluoride-resistant strains were derived from laboratory strains or were recently isolated strains from xerostomic patients on high-dose fluoride therapy. The demineralization model was composed of a cell suspension in a glucose-agarose gel overlying a bovine enamel block. Lactate and calcium content of the agarose were determined after 22-hour incubations at 37°C. Fluoride-resistant variants of Streptococcus sobrinus 6715-15 produced less lactate and caused less demineralization than did the parent strain even in the presence of fluoride. On the other hand, fluoride-resistant variants of Streptococcus mutans C180-2 and of S. mutans GS-5 produced more acid and caused greater demineralization than did their respective parent strains, both in the absence and presence of fluoride. Two recently isolated fluoride-resistant S. mutans strains produced more lactate and demineralized enamel more than did two recently isolated S. mutans strains from normal human subjects, both in the presence of 0 and 0.05 mmol/L NaF. It is concluded that adaptation to fluoride resistance does not invariably reduce the cariogenicity of mutans streptococci nor the effectiveness of fluoride in preventing demineralization.

scholarly journals Coimmunization with Complementary Glucosyltransferase Peptides Results in Enhanced Immunogenicity and Protection against Dental Caries

2000 ◽  
Vol 68 (5) ◽  
pp. 2698-2703 ◽  
Author(s):  
Martin A. Taubman ◽  
Daniel J. Smith ◽  
Cynthia J. Holmberg ◽  
Jean W. Eastcott
Keyword(s):  
Dental Caries ◽  
Functional Significance ◽  
Serum Antibody ◽  
Mutans Streptococci ◽  
Streptococcus Sobrinus ◽  
Insoluble Glucan ◽  
Glucan Synthesis ◽  
The Individual ◽  
Antibody Levels

ABSTRACT Peptide constructs from the catalytic (CAT) and glucan-binding (GLU) regions of the mutans streptococcal glucosyltransferase enzymes (GTF) can provide immunity to dental caries infection. A strategy of coimmunization was tested to determine whether protection could be enhanced. Rats were immunized with one of the previously described peptide constructs from the CAT or GLU region of the GTF of mutans streptococci or coimmunized with a combination of these constructs (CAT-GLU). Coimmunized animals demonstrated significantly higher serum immunoglobulin G (IgG) and salivary IgA antibody levels to CAT or GTF than rats immunized with either construct alone. To assess the functional significance of coimmunization with these constructs, animals were immunized as above or with Streptococcus sobrinus GTF and then infected with S. sobrinus to explore the effects of immunization on immunological, microbiological, and disease (dental caries) parameters. Serum antibody from the communized group inhibited S. sobrinus GTF-mediated insoluble glucan synthesis in vitro above that of the individual-construct-immunized groups. Immunization with CAT or GLU constructs resulted in significantly reduced dental caries after infection with S. sobrinus compared with sham-immunized animals. Coimmunization produced greater reductions in caries than after immunization with either CAT or GLU. Also, significant elevations in lymphocyte proliferative responses to CAT, GLU, and GTF were observed after coimmunization with CAT-GLU compared with the responses after immunization with the individual constructs. The results suggested that increased numbers of memory T cells, which could proliferate to CAT, were generated by coimmunization. The experiments support the functional significance of these GTF domains in dental caries pathogenesis and present coimmunization as a simple alternative to intact GTF to enhance protective immunity against cariogenic microorganisms.

Clone selection of in vitro horseradish hairy root cultures

Planta Medica ◽  
2015 ◽  
Vol 81 (16) ◽  
Author(s):  
R Bertóti ◽  
Á Alberti ◽  
A Böszörményi ◽  
R Könye ◽  
T Horváth ◽  
...  
Keyword(s):  
Hairy Root ◽  
Hairy Root Cultures ◽  
Root Cultures ◽  
Clone Selection ◽  
Selection Of

The Use of High - Sucrose Culture Media for the Identification of Oral Streptococci in Infant- Mother Pairs

2017 ◽  
Vol 68 (11) ◽  
pp. 2691-2693
Author(s):  
Krisztina Martha ◽  
Cristina Bica ◽  
Edva Anna Frunda
Keyword(s):  
Culture Media ◽  
Bacterial Flora ◽  
Mutans Streptococci ◽  
Resistant Bacteria ◽  
Oral Streptococci ◽  
Streptococcus Sobrinus ◽  
Sugar Intake ◽  
Tooth Surfaces ◽  
Refined Carbohydrates ◽  
High Sucrose

By the end of the 60�s, the theory that refined carbohydrates promotes the absorption of saccharolytic Gram-positive microbial species on the tooth surfaces has become generally. Mutans streptococci (Streptococcus mutans and Streptococcus sobrinus) were key players in this theory. On agar plates, Str. mutans produces small, circular colonies, in the presence of glucose, and in the presence of sucrose large, sticky, gelatinous colonies. This gelatinous texture is due to the shell material: mutant 1 � 3 glucose polymers and dextran 1 �! 6 glucose polymers. Str. mutans are able to survive in the oral cavity with a pH lower than 5.5. That is why consecutive multiple sugar intake promotes the colonization of Str. mutans, which results in dental caries in stagnant zones. As oral pH is continuously shifted to acid, more acid-resistant bacteria appear. Our aim was to identify species in infant-mother pair gingival crevicular bacterial flora, which can be detected on high-sucrose culture media and to underline the jeopardy of vertical oral contamination from mother to infant.

The Effects of Shock Vancomycin Concentrations on the Formation of Heteroresistance in Staphylococcus aureus

2020 ◽  
Vol 65 (9-10) ◽  
pp. 3-7
Author(s):  
V. V. Gostev ◽  
Yu. V. Sopova ◽  
O. S. Kalinogorskaya ◽  
M. E. Velizhanina ◽  
I. V. Lazareva ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vitro Selection ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
High Concentration ◽  
Short Term ◽  
High Concentrations ◽  
Selection Of ◽  
Selection Of Resistance ◽  
Test Cultures

Glycopeptides are the basis of the treatment of infections caused by MRSA (Methicillin-Resistant Staphylococcus aureus). Previously, it was demonstrated that antibiotic tolerant phenotypes are formed during selection of resistance under the influence of high concentrations of antibiotics. The present study uses a similar in vitro selection model with vancomycin. Clinical isolates of MRSA belonging to genetic lines ST8 and ST239, as well as the MSSA (ATCC29213) strain, were included in the experiment. Test isolates were incubated for five hours in a medium with a high concentration of vancomycin (50 μg/ml). Test cultures were grown on the medium without antibiotic for 18 hours after each exposure. A total of ten exposure cycles were performed. Vancomycin was characterized by bacteriostatic action; the proportion of surviving cells after exposure was 70–100%. After selection, there was a slight increase in the MIC to vancomycin (MIC 2 μg/ml), teicoplanin (MIC 1.5–3 μg/ml) and daptomycin (MIC 0.25–2 μg/ml). According to the results of PAP analysis, all strains showed an increase in the area under curve depending on the concentration of vancomycin after selection, while a heteroresistant phenotype (with PAP/AUC 0.9) was detected in three isolates. All isolates showed walK mutations (T188S, D235N, E261V, V380I, and G223D). Exposure to short-term shock concentrations of vancomycin promotes the formation of heteroresistance in both MRSA and MSSA. Formation of VISA phenotypes is possible during therapy with vancomycin.

Wheat Germ Cell-Free Translation System as a Tool for In vitro Selection of Functional Proteins

2002 ◽  
Vol 5 (6) ◽  
pp. 473-480
Author(s):  
Bentham Science Publisher A.N. Alexandrov ◽  
Bentham Science Publisher V.Yu. Alakhov ◽  
Bentham Science Publisher A.I. Miroshnikov
Keyword(s):  
Germ Cell ◽  
Wheat Germ ◽  
In Vitro Selection ◽  
Translation System ◽  
Free Translation ◽  
Selection Of
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