332 Microbes and You 



Rheumatic fever may develop in children following repeated 

 infections of the respiratory tract caused by streptococci. Fever, 

 pain in the joints, and involvement of the heart valves are common 

 symptoms of rheumatic fever. While streptococci are not usually 

 isolated from these foci of disease, evidence is strong that the 

 products of streptococcus metabolism are the direct cause of the 

 symptoms. 



Septic sore throat is an acute infection involving the tonsils 

 and Ivmph nodes, with an accompanying fever and prostration. 

 Epidemics of this disease have been traced to raw milk con- 

 taminated by an infected handler, although droplet infection may 

 also initiate epidemics. 



Septicemia may result from improper treatment of flesh wounds 

 and if the blood poisoning is allowed to progress, death may follow. 



Other diseases of streptococcal origin include subacute bac- 

 terial ENDOCARDITIS ( iuf cctiou of the heart valves), erysipelas 

 (an acute specific inflammation of the skin), puerperal fever 

 ( child-bed fever ) , and scarlet fever. 



MICROCOCCI 



Spherical cells, usually less than 1.0 micron in diameter, gen- 

 erally gram positive in young cultures. Occur in singles, pairs, 

 tetrads, packets, or irregular masses. Motility rare. Preferably 

 aerobic. Facultative parasites and saprophytes with an optimum 

 growth temperature between 22° -37° C. Frequently live on 

 the skin, in skin glands or skin gland secretions of vertebrates 

 (animal having a spinal column). Cause of many localized 

 infections. 



Pasteur recognized these spherical bacteria in 1880, and the 

 organisms were first isolated from an abscess by Ogsten in 1881. 

 Rosenbach described differences in pigmentation of colonies of 

 these cocci which today are designated albiis (white), aureus 

 ( golden ) , citreus ( lemon yellow ) , and lutea ( yellow ) . 



Micrococcus pyogenes var. alhus (formerly known as Staphy- 

 lococcus albus), and Micrococcus pyogenes var. aureus (formerly 

 Staphylococcus aureus) are the most common micrococci im- 



