scholarly journals Synergistic hemolysis phenomenon shown by an alpha-toxin-producing Clostridium perfingens and streptococcal CAMP factor in presumptive streptococcal grouping

1978 ◽  
Vol 8 (5) ◽  
pp. 480-488
Author(s):  
S M Gubash
Keyword(s):  
Human Blood ◽  
Test Group ◽  
Blood Agar ◽  
Group A Streptococci ◽  
Alpha Toxin ◽  
Group B Streptococci ◽  
Camp Factor ◽  
Group A ◽  
Camp Test ◽  
Group B

A new phenomenon of synergistic hemolysis by Clostridium perfringens alpha-toxin and the streptococcal CAMP factor on human and guinea pig erythrocytes is described. A possible mode of action of the CAMP factors is suggested. On human blood agar all of the tested isolates of group B streptococci gave an arrowhead-shaped zone of hemolysis; 74% of group A gave a crescent-shaped lytic zone, whereas all isolates of groups C and G and the remaining 26% of group A streptococci gave a bullet-shaped lytic zone. By comparison, in the CAMP test incubated aerobically and anaerobically, 70 and 91%, respectively, of streptococci other than group B gave positive, arrowhead-shaped lytic zones. If all intermediate positive reactions in the CAMP tests were read as negative after aerobic incubation, only 89% of group B streptococci would be properly identified. The synergistic hemolysis phenomenon, using an alpha-toxin-producing C. perfringens and human blood agar, provided a reliable test for presumptive identification of group B streptococci, with promising potential to differentiate in the same test group A streptococci from other groups.

scholarly journals Doubly Branched Hexasaccharide Epitope on the Cell Wall Polysaccharide of Group A Streptococci Recognized by Human and Rabbit Antisera

2005 ◽  
Vol 73 (10) ◽  
pp. 6383-6389 ◽  
Author(s):  
Francis Michon ◽  
Samuel L. Moore ◽  
John Kim ◽  
Milan S. Blake ◽  
France-Isabelle Auzanneau ◽  
...  
Keyword(s):  
Cell Wall ◽  
Rabbit Antiserum ◽  
Cell Wall Polysaccharide ◽  
Group A Streptococci ◽  
Group B Streptococci ◽  
Group A ◽  
Streptococcal Polysaccharide ◽  
Synthetic Oligosaccharides ◽  
Group B ◽  
Dominant Epitope

ABSTRACT A number of epitope specificities associated with the cell wall polysaccharide antigen of group A streptococci were identified in a polyclonal rabbit antiserum induced in rabbits by whole group A streptococci and in polyclonal convalescent human antisera from children that had recovered from streptococcal A infections. The identification was achieved by using a series of synthetic oligosaccharides, glycoconjugates, and bacterial polysaccharide inhibitors to inhibit the binding of the group A helical polysaccharide to the polyclonal antisera. The exclusively dominant epitope expressed in the convalescent human antisera was the doubly branched extended helical hexasaccharide with the structure α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap(1→3)α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap. The hexasaccharide epitope also bound with the highest immunoreactivity to the rabbit antiserum. In contrast, the human antisera did not show significant binding to the singly branched pentasaccharide with the structure α-l-Rhap(1→2)α-l-Rhap(1→3)α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap or the branched trisaccharide α-l-Rhap(1→2)[β-d-GlcpNAc(1→3)]α-l-Rhap, although both these haptens bound significantly to the same rabbit antiserum, albeit with less immunoreactivity than the hexasaccharide. Inhibition studies using streptococcal group A and B rabbit antisera and the inhibitors indicated above also suggested that the group A carbohydrate, unlike the group B streptococcal polysaccharide, does not contain the disaccharide α-l-Rhap(1→2)α-l-Rhap motif at its nonreducing chain terminus, stressing the importance of mapping the determinant specificities of these two important streptococcal subcapsular group polysaccharides to fully understand the serological relationships between group A and group B streptococci.

CAMP test v1

2021 ◽  
Author(s):  
lydiariver not provided
Keyword(s):  
Staphylococcus Aureus ◽  
Streptococcus Agalactiae ◽  
Group B Streptococcus ◽  
Blood Agar ◽  
Camp Factor ◽  
Camp Test ◽  
Group B

Group B Streptococcus agalactiae has CAMP factor which allow it to hemolized zones when it is grown on blood agar plates near to Staphylococcus aureus ATCC 25293 colonies, this effect is brought about by Staphylococcus aureus sphingomyelinase.

scholarly journals In Vitro Activities of Two Ketolides, HMR 3647 and HMR 3004, against Gram-Positive Bacteria

1999 ◽  
Vol 43 (4) ◽  
pp. 930-936 ◽  
Author(s):  
Kumthorn Malathum ◽  
Teresa M. Coque ◽  
Kavindra V. Singh ◽  
Barbara E. Murray
Keyword(s):  
Dilution Method ◽  
Agar Dilution Method ◽  
Group A Streptococci ◽  
Group B Streptococci ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Streptococci Group B ◽  
Group A ◽  
Group B

ABSTRACT The in vitro activities of two new ketolides, HMR 3647 and HMR 3004, were tested by the agar dilution method against 280 strains of gram-positive bacteria with different antibiotic susceptibility profiles, including Staphylococcus aureus,Enterococcus faecalis, Enterococcus faecium,Streptococcus spp. (group A streptococci, group B streptococci, Streptococcus pneumoniae, and alpha-hemolytic streptococci). Seventeen erythromycin-susceptible (Ems), methicillin-susceptible S. aureus strains were found to have HMR 3647 and HMR 3004 MICs 4- to 16-fold lower than those of erythromycin (MIC at which 50% of isolates were inhibited [MIC50] [HMR 3647 and HMR 3004], 0.03 μg/ml; range, 0.03 to 0.06 μg/ml; MIC50 [erythromycin], 0.25 μg/ml; range, 0.25 to 0.5 μg/ml). All methicillin-resistant S. aureus strains tested were resistant to erythromycin and had HMR 3647 and HMR 3004 MICs of >64 μg/ml. The ketolides were slightly more active against E. faecalis than against E. faecium, and MICs for individual strains varied with erythromycin susceptibility. The MIC50s of HMR 3647 and HMR 3004 against Ems enterococci (MIC ≤ 0.5 μg/ml) and those enterococcal isolates with erythromycin MICs of 1 to 16 μg/ml were 0.015 μg/ml. E. faecalis strains that had erythromycin MICs of 128 to >512 μg/ml showed HMR 3647 MICs in the range of 0.03 to 16 μg/ml and HMR 3004 MICs in the range of 0.03 to 64 μg/ml. In the group of E. faecium strains for which MICs of erythromycin were ≥512 μg/ml, MICs of both ketolides were in the range of 1 to 64 μg/ml, with almost all isolates showing ketolide MICs of ≤16 μg/ml. The ketolides were also more active than erythromycin against group A streptococci, group B streptococci,S. pneumoniae, rhodococci, leuconostocs, pediococci, lactobacilli, and diphtheroids. Time-kill studies showed bactericidal activity against one strain of S. aureus among the four strains tested. The increased activity of ketolides against gram-positive bacteria suggests that further study of these agents for possible efficacy against infections caused by these bacteria is warranted.

scholarly journals Selective and enhanced recovery of group A and B streptococci from throat cultures with sheep blood agar containing sulfamethoxazole and trimethoprim

1977 ◽  
Vol 5 (6) ◽  
pp. 650-655
Author(s):  
B A Gunn ◽  
D K Ohashi ◽  
C A Gaydos ◽  
E S Holt
Keyword(s):  
Enhanced Recovery ◽  
Initial Study ◽  
Selective Medium ◽  
Sheep Blood Agar ◽  
Blood Agar ◽  
Viridans Streptococci ◽  
Group B Streptococci ◽  
Sheep Blood ◽  
Group A ◽  
Group B

Sheep blood agar containing 23.75 microgram of sulfamethoxazole and 1.25 microgram of trimethoprim (SXT-BA) per ml was compared with conventional sheep blood agar (SBA) for isolating group A and B streptococci from throat cultures. This selective medium allowed much better recovery of group A and B streptococci and suppressed the growth of the normal flora, including "viridans" streptococci. In an initial study of 700 throat cultures, SXT-BA recovered 42% more group A and 49% more group B streptococci than did SBA. When SXT-BA was introduced into the routine microbiology laboratory and used by a number of medical technologists. SXT-BA recovered 28% more group A and 37% more group B streptococci than did SBA. In addition, the selective medium inhibited 83% of the non-group A and B streptococci that were recovered by SBA.

scholarly journals The Bone Buttress Theory: The Effect of the Mechanical Loading of Bone on the Osseointegration of Dental Implants

Biology ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 12
Author(s):  
David Chavarri-Prado ◽  
Aritza Brizuela-Velasco ◽  
Ángel Álvarez-Arenal ◽  
Markel Dieguez-Pereira ◽  
Esteban Pérez-Pevida ◽  
...  
Keyword(s):  
Dental Implants ◽  
Mechanical Loading ◽  
Bone Growth ◽  
Bone Matrix ◽  
Test Group ◽  
Control Group ◽  
Group A ◽  
Bone To Implant Contact ◽  
The Stability ◽  
Group B

Objectives: To determine the effect of mechanical loading of bone on the stability and histomorphometric variables of the osseointegration of dental implants using an experimental test in an animal model. Materials and Methods: A total of 4 human implants were placed in both tibiae of 10 New Zealand rabbits (n = 40). A 6-week osseointegration was considered, and the rabbits were randomly assigned to two groups: Group A (Test group) included 5 rabbits that ran on a treadmill for 20 min daily during the osseointegration period; Group B (Controls) included the other 5 that were housed conventionally. The monitored variables were related to the primary and secondary stability of the dental implants (implant stability quotient—ISQ), vertical bone growth, bone to implant contact (BIC), area of regenerated bone and the percentage of immature matrix. Results: The results of the study show a greater vertical bone growth (Group A 1.26 ± 0.48 mm, Group B 0.32 ± 0.47 mm, p < 0.001), higher ISQ values (Group A 11.25 ± 6.10 ISQ, 15.73%; Group B 5.80 ± 5.97 ISQ, 7.99%, p = 0.006) and a higher BIC (Group A 19.37%, Group B 23.60%, p = 0.0058) for implants in the test group, with statistically significant differences. A higher percentage of immature bone matrix was observed for implants in the control group (20.68 ± 9.53) than those in the test group (15.38 ± 8.84) (p = 0.108). A larger area of regenerated bone was also observed for the test implants (Group A 280.50 ± 125.40 mm2, Group B 228.00 ± 141.40 mm2), but it was not statistically significant (p = 0.121). Conclusions: The mechanical loading of bone improves the stability and the histomorphometric variables of the osseointegration of dental implants.

Resorbable Collagen Barrier Impeding the Extrusion of Obturating Material in Primary Molars Undergoing Resorption – A Randomized Clinical Trial

2021 ◽  
Vol 45 (5) ◽  
pp. 312-316
Author(s):  
Mishra Neha Sanjeev ◽  
Harsimran Kaur ◽  
Sandeep Singh Mayall ◽  
Rishika ◽  
Ramakrishna Yeluri
Keyword(s):  
Test Group ◽  
Primary Molars ◽  
Control Group ◽  
Chi Square ◽  
Significance Level ◽  
Significant Difference ◽  
Chi Square Test ◽  
Group A ◽  
Group B ◽  
And Control

Objective: To evaluate the effectiveness of placing a resorbable collagen barrier in impeding the extrusion of obturation material in primary molars undergoing resorption. Study design: All the 94 canals in 47 mandibular molars were allocated to 2 groups- Group ‘A’- 47 canals with collagen barrier (Test group) and Group ‘B’- 47 canals without collagen barrier (Control group) based on randomization protocol. Pulpectomy was performed and obturation of both test and control canals were radiographically assessed. Pearson’s chi – square test was applied to analyze the results. The significance level was predetermined at p &lt; 0.05. Results: Among the test group, 93.6% of the canals showed no extrusion while, 6.4% showed visible extrusion of the material outside the apex. In the control group, 83% showed no extrusion whereas 17% of the canals showed visible extrusion outside the apex. But no significant difference was noted (p&gt;0.05). Conclusion: The placement of resorbable collagen barrier in the apical third of the canal prevented the extrusion of obturating material beyond the apex in resorbing primary molars.

Single-choice or multiple true false questions (Kprime):Direct comparison of online tests in pharmacology over one year (Preprint)

2021 ◽  
Author(s):  
Joachim Neumann ◽  
Stephanie Simmrodt ◽  
Beatrice Bader ◽  
Bertram Opitz ◽  
Ulrich Gergs
Keyword(s):  
Medical Students ◽  
Multiple Choice ◽  
Test Group ◽  
Learning Objectives ◽  
Multiple Choice Questions ◽  
Online Test ◽  
True Answer ◽  
Group A ◽  
One Year ◽  
Group B

BACKGROUND There remain doubts about whether multiple choice answer formats (single choice) offer the best option to encourage deep learning or whether SC formats simply lead to superficial learning or cramming. Moreover, cueing is always a drawback in the SC format. Another way to assess knowledge is true multiple-choice questions in which one or more answers can be true and the student is not aware of how many true answers are to be anticipated (K´ or Kprime question format). OBJECTIVE Here, we compared both single-choice answers (one true answer, SC) with Kprime answers (one to four true answers out of four answers, Kprime) for the very same learning objectives in a study of pharmacology in medical students. METHODS Two groups of medical students were randomly subjected to a formative online test: group A) was first given 15 SC (#1-15) followed by 15 different Kprime questions (#16-30). The opposite design was used for group B. RESULTS The mean number of right answers was higher for SC than for Kprime questions in group A (10.02 vs. 8.63, p < 0.05) and group B (9.98 vs. 6.66, p < 0.05). The number of right answers was higher for nine questions of SC compared to Kprime in group A and for eight questions in group B (pairwise T-Test, p < 0.05). Thus, SC is easier to answer than the same learning objectives in pharmacology given as Kprime questions. One year later, four groups were formed from the previous two groups and were again given the same online test but in a different order: the main result was that all students fared better in the second test than in the initial test; however, the gain in points was highest if initially mode B was given. CONCLUSIONS Kprime is less popular with students being more demanding, but could improve memory of subject matter and thus might be more often used by meidcal educators.

Evaluation of spot CAMP test for identification of group B streptococci.

1986 ◽  
Vol 24 (2) ◽  
pp. 296-297 ◽  
Author(s):  
H B Ratner ◽  
L S Weeks ◽  
C W Stratton
Keyword(s):  
Group B Streptococci ◽  
Camp Test ◽  
Group B
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