Microbiology

Microbiology Study Guide

Pertussis (Whooping Cough) The gram-negative bacterium Bordetella pertussis causes pertussis, also known as whooping cough. The disease is transmitted by airborne droplets. The microbes enter and grow in the trachea and bronchi of the affected person and symptoms include cough paroxysms. The sound of the cough is associated with the high-pitched whooping sound. Treatment of pertussis is possible by using antibiotics, including erythromycin and the DPT vaccine clubbed with killed pertussis bacilli or a DTaP vaccine consisting of acellular fragments of the bacteria. Strep Throat The gram-positive betahemolytic streptococcus bacterium belonging to group A, from the species of Streptococcus pyogenes, causes a strep throat infection. The organism generates streptokinase and fibrin clots in the body as the organism travels and infects other tissues in the body. Symptoms include inflammation of the lymph nodes and the formation of pus cells on the tonsils. A physician is able to diagnose the presence of an infection by testing the throat swab with antibodies coated with beads and then looking for the clumping of beads. If clumping occurs, it indicates the presence of the organism. Treatment of the infection is done by prescribing antibodies, including penicillin. Scarlet Fever The gram-positive bacterium Streptococcus pyogenes (similar to strep throat) causes scarlet fever. The organism generates an erythrogenic toxin that penetrates and causes infection. Major symptoms include rashes on the skin, high fever, inflammation of tissues in the throat, and strawberry tongue, which is when the tongue resembles a strawberry. Treatment is usually antibiotic drug therapy, like penicillin. Otitis Media Otitis media is a bacterial disease caused by the species of bacteria Streptococcus pneumoniae, Haemophilus influenzae , and Staphylococcus aureus. Symptoms include an infection in the middle ear followed by a severe ache in the ears. The infection is generally cured by prescribing antibiotics. Pneumococcal Pneumonia The gram-positive cocci bacterium Streptococcus pneumonia is responsible for causing pneumococcal pneumonia. The organism produces and infects in chains. Major symptoms include infection in the tissues of the lungs, high fever, bacteria-filled lungs, fluid and debris, blood in sputum, and severe chest pain. There are currently more than 100 serological types of these bacteria, but unfortunately, only one-fourth of them are covered by vaccination. Treatment for this disease is usually done by prescribing aggressive antibiotic drug therapy, including penicillin. Mycoplasmal Pneumonia From the species of the submicroscopic bacteria mycoplasma, mycoplasmal pneumonia is caused by the genus of Mycoplasma pneumoniae . Pneumonia at its early stage, which is known as walking pneumonia, is the main symptom. As the size of the organism causing the disease is very small and has no cell, penicillin is not an adequate drug to treat the infection; erythromycin is used instead.

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