Related Experiment Video
Updated: Feb 13, 2026

Experimental Human Pneumococcal Carriage
Published on: February 15, 2013
Atypical Pneumococcal Isolate from Blood
Jayashree Veerasamy1, Jayalakshmi Jayarajan2
1Department of Microbiology, Shri Sathya Sai Medical College and Research Institute, Kanchipuram, India.
Abstract:
Pneumonia with bacteremia accounts for the majority (70%) of cases of invasive pneumococcal diseases. Laboratory characterization of pneumococci is routinely done by sensitivity to optochin. We identified an atypical presentation of optochin-resistant pneumococci in blood isolate of a patient with sepsis. Polymerase chain reaction for autolysin (lytA) and pneumolysin (ply) was positive in the bile soluble isolate. Gene sequencing revealed synonymous single nucleotide polymorphism type of functional mutation in lytA gene. There have been emerging reports of optochin-resistant pneumococci. Diminishing relevance and reliability of optochin sensitivity testing in identifying pneumococci in clinical samples has been highlighted by this case report.
Related Concept Videos
Antipsychotic Drugs: Typical and Atypical Agents
Composition of Blood
Formed elements constitute the remaining 45% of the blood volume. These...
Blood Flow
Blood Types
ABO blood group
ABO antigens are glycoproteins encoded by genes present on...
Blood Pressure
Blood Pressure
The average BP in an adult is typically around 120/80 mmHg (millimeters of mercury). In this measurement, the numerator (120) indicates the systolic pressure, which is the pressure in the arteries during the contraction of the heart's ventricles as blood is expelled. The denominator (80) represents the...

