CAMP test

Streptococcus

Published in Dongyou Liu, Laboratory Models for Foodborne Infections, 2017

Dongyou Liu

Based on the hemolytic properties detected on blood agar plates, members of the genus Streptococcus are distinguished into three categories: α-, β-, and γ-hemolysis. α-Hemolytic species produce hydrogen peroxide that oxidizes hemoglobin within red blood cells to become green methemoglobin, leading to a greenish and dark zone surrounding and underneath the colonies with short chains (as in the case of S. pneumoniae and S. viridans or viridans streptococci; viridans, from Latin vĭrĭdis, green). β-Hemolytic species produce streptolysins (e.g., streptolysin O and streptolysin S) that cause complete lysis of red blood cells in blood agar plate, giving a clear (lightened/yellow and transparent) zone around and underneath the colonies with short chains (as in the case of S. haemolyticus). More specifically, streptolysin O (SLO, an oxygen-sensitive cytotoxin secreted by most GAS) interacts with cholesterol in the membrane of eukaryotic cells (red and white blood cells, macrophages, and platelets), causing β-hemolysis under the surface of blood agar. Streptolysin S (SLS, an oxygen-stable cytotoxin also secreted by most GAS strains) induces clearing on the surface of blood agar. It is notable that some weakly β-hemolytic species (e.g., S. agalactiae, Clostridium perfringens, and Listeria monocytogenes) cause intense β-hemolysis when grown together with a strain of Staphylococcus (so called the CAMP test). γ-Hemolytic species cause no hemolysis (no change) on blood agar (as in the case of enterococci) [3].

Published in Ronald M. Atlas, James W. Snyder, Handbook Of Media for Clinical Microbiology, 2006

Ronald M. Atlas, James W. Snyder

Use: Used as a base that is supplemented. For the cultivation of fastidious microorganisms. When supplemented with sheep blood, this medium is useful for the observation of hemolytic reactions of a variety of bacteria. It may be used to perform the CAMP test for the presumptive identification of group B streptococci (Streptococcus agalactiae).

Effect of signal processing strategy and stimulation type on speech and auditory perception in adult cochlear implant users

Published in International Journal of Audiology, 2019

Susan M. Reynolds, René H. Gifford

In theory, current steering programmes, specifically Fidelity-120, hold potential for greater music-based spectral resolution; however, as described above, we did not observe an effect of strategy for musical chord discrimination. The range of scores for this task was 63.3%–65.2%, which was only slightly higher than chance (50%). Though listeners with normal hearing can discriminate <1 semitone, it takes between 3.0 and 7.5 semitones, on average, for adult CI users to detect a difference in pitch (e.g. Fujita and Ito 1999; Kang et al. 2009; Drennan et al. 2015). Chords presented in this study only differed by one semitone, which was likely not a perceptual difference for many subjects. Thus, the lack of effect of strategy – specifically current steering versus HiRes – may be attributed to the limitation of the chord discrimination measure. These results are consistent with findings of Drennan et. al (2010) who found no difference in performance on the Clinical Assessment of Music Perception (CAMP) test of pitch discrimination (Kang et al. 2009) across Fidelity-120 and HiRes. Even though there were no significant differences across strategy for the current study, it is important to note that participant 3 opted to keep Fidelity-120-S for use as a music programme after the experiment was finished as he reported better music perception and appreciation with this strategy. This was not the programme that resulted in the highest performance for chord discrimination, but the listener reported a preference for music-based sound quality. It is possible that the familiarisation time was not long enough for this participant. Given more time to acclimate to the new programme, the subjective benefit may have resulted in higher performance.

Group B streptococcal carriage, antimicrobial susceptibility, and virulence related genes among pregnant women in Alexandria, Egypt

Published in Alexandria Journal of Medicine, 2018

Salama Mohamed Sadaka, Hala Abdelsalam Aly, Marwa Ahmed Meheissen, Yasser Ibrahim Orief, Basma Mohamed Arafa

The inoculated CHROMagar™ StrepB and blood agar plates were incubated aerobically at 35–37 °C for 18–24 h in 5% CO2.The inoculated selective broth was incubated for 18–24 h at 35–37 °C in 5% CO2, then was subcultured onto CHROMagar™ StrepB, and sheep blood agar and incubated aerobically at 35–37 °C for another18–24 h in 5% CO2.After incubation period, plates were examined. The suspected GBS colonies on CHROMagar™ StrepB (mauve colonies) and on blood agar (b-haemolytic and non-haemolytic) were picked and subcultured onto sheep blood agar and incubated aerobically at 35–37 °C for 18–24 h in 5% CO2. Isolates were identified using conventional methods on the basis of colonial morphology, Gram staining, haemolysis, CAMP test, bile esculin, hippurate hydrolysis (Liofilchem, Italy), and latex agglutination test with specific antisera (Strepto B latex kit, Liofilchem, Italy).23 (Fig. 1).The isolated identified strains were stored in Todd- Hewitt broth along with 15% glycerol at −70 °C until tested. The negative culture results were issued at 72 h, according to the CDC recommendations.

Intrauterine Bacterial Colonization and Endometrial MicroRNA-17-5p Levels in Association to Endometriosis: A Study in an Egyptian Population

Published in Immunological Investigations, 2020

Yasmin Nabiel, Heba ELshahawy, Alaa Mosbah

The inoculated plates were incubated both aerobically and anaerobically for 24–48 h and the resulting colonies were identified by colony morphology, hemolysis appearance, Gram staining pattern and suitable biochemical reactions such as catalase, bacitracin sensitivity test, CAMP test, bile esculin hydrolysis, and IMVC tests. All colonies were counted for each plate to be shown in terms of log transformation of colony forming units (CFU/ml).