sign in sign up
<<
Home , Oswald Avery, Rebecca Lancefield

The Legacy of

Serogrouping of Strep

ome species of pneumoniae is easily streptococci are unique in distinguished from other S that they are classified or Streptococci by its alpha grouped according to the hemolysis, sensitivity to antigenic structure of their optochin, and solubility in bile. walls. Ever wondered how this was discovered? In this article The other major group of we will explore the history of streptococci, the beta-hemolytic how strep grouping came to be streps, are rather difficult to By Christopher Massey in common usage today. differentiate based on June, 2015 biochemical tests alone. They The genus all produce streptolysin, which contains many pathogens from is responsible for their ability to numerous body sites. Over 50 lyse blood cells, and can Christopher Massey is the species of these gram-positive typically be pathogenic to Research and Development cocci are currently recognized. humans and other animals. Manager at Hardy Diagnostics. From a clinical perspective, He earned his degree in Streptococcus species are microbiology at Cal Poly in separated into two major San Luis Obispo, California. groups: alpha- and beta-

hemolytic for their characteristic

HardyDiagnostics.com growth on Blood Agar plates. A well-known example of alpha-hemolytic Streptococcus is , which causes inflammatory

conditions such as otitis media, Rapid Strep Grouping Kits, such as sinus infections and even StrepPRO, are a result of Dr. Lancefield’s meningitis or sepsis. Other diligent work in discovering the alpha-hemolytic streptococci serogroups of beta hemolytic strep. include the , which are normally Originally termed Streptococcus commensal and rarely cause hemolyticus as a group, it was disease, with a notable apparent in the early 1900’s that exception being subacute these organisms warranted bacterial endocarditis. S. further classification. It was this realization that led Rebecca was offered a position at the “By the reaction of ‘agglutination,’ Lancefield to perform her Rockefeller Institute for four distinct immunological types and a certain number of groundbreaking work on Medical Research as a technical unclassifiable strains have been classifying these organisms into assistant in the lab of Dr. discovered among the 125 strains 18 categories that would later be Alphonse Dochez, who studied. Individuals of the same known as “Lancefield discovered that the common type are closely related to one Groupings.” These groupings cold was caused by a virus, and another immunologically, and the different types can be sharply provide the basis for Dr. , one of the distinguished one from the other.” identification of these fathers of immunochemistry, potentially dangerous organisms and whose team discovered that The strains have been saved to that we use today. DNA is the molecule that this day and some became encodes genetic information. reference strains for Group A Rebecca Craighill Lancefield Lancefield remained at the streptococci in the Lancefield was born in , New Rockefeller Institute (now the collection. York in 1895 to a colonel in the ) for 40 U.S. Army Corps of Engineers. years until she retired in 1965. Lancefield's work involved She spent her childhood preparing by collecting travelling from city to city as Her early work focused on centrifuged from broth many children of military pneumococcus, but quickly cultures for 18 hours, and re- families often do. She originally shifted to research on the suspending them in an studied English at Wellesley various Streptococcus HCl/NaCl mixture. The mixture College in Massachusetts. hemolyticus outbreaks at was then heated, neutralized military facilities during World with NaOH and the precipitate War I. It was not known at the discarded. The resulting time whether the infections were supernatant would contain the due to a single virulent species, mixture Lancefield used or the result of a group of for her precipitin tests. The distinct separate species antigen mixture could be previously categorized as one concentrated by using group. Lancefield’s work was consecutive overnight inspired by Dr. Avery’s earlier treatments of a sodium work using serological methods acetate/alcohol precipitation. to agglutinate and identify pneumococcus species. The Lancefield used were prepared by inoculating Within a year, Rebecca rabbits with heat-killed broth Lancefield’s diligent work cultures, followed by Sparked by an interest in a initially identified four distinct inoculation with live cultures. 6- class, Lancefield serogroups of streptococci 8 weeks later, the rabbit serum changed her major and pursued which composed 70% of 125 was collected and could be used graduate work at Columbia initial strains under study. As a for agglutination tests. Because University in the field of co-author, she, Dr. Dochez and non-specific precipitin reactions bacteriology. Dr. Avery published their with antigens of heterologous landmark findings in the Journal strains mixed with the pure Upon obtaining her master’s of Experimental Medicine on serum, an adsorption treatment degree at Columbia, Lancefield June 1 of 1919. She concluded: was necessary. This involved mixing antigens of the was noticed that streptococci response of one serotype of S. heterologous strains with the from throat infections shared a pyogenes did not confer lasting inoculated rabbit serum and C carbohydrate that was protection to the more than 60 allowing the precipitin reaction serologically distinct from the C other known types of S. to occur, thus cleaning out any carbohydrate of streptococci pyogenes. non-specific antibodies as well isolated from bovine mastitis as any other agglutinating and both were distinct from By 1940, her work led to the factors in the serum. The result strains isolated from equine serological grouping of beta- was a clean serum that was strangles. It seemed that hemolytic streptococci known type-specific for the antigen of streptococcal disease and C as Lancefield’s groupings (A-H, the organism that the rabbit was carbohydrate type were L and M). Her contributions originally inoculated with. correlated. toward our understanding of These sera could be used to pathogenic streptococci are characterize unknown Four years of Lancefield’s work innumerable and have shaped Streptococci into serogroups. with the M and C the way we identify and treat carbohydrate culminated in streptococcal infections. In Lancefield later pursued her 1928 with the rapid publication addition, they provide the basis Ph.D at on of seven papers in the Journal of for the epidemiological study of the study of viridans Experimental Medicine. streptococcal groups. streptococci and their possible Initially, the human strains of link to . streptococci that shared a C Lancefield’s work contributed antigen were termed “Group A.” to discredit this link. Group B streptococci were initially isolated and classified From 1924-1928, Lancefield from bovine sources. Group C discovered two different types streptococci were isolated from of antigenic targets within an epizootic in guinea pigs. Streptococcus hemolyticus. One was the M protein, associated Starting in 1938, Dr. Lancefield with the ‘matte’ appearance of also was able to classify the colonies when grown on agar Group B Streptococci into Through and beyond World War and is related to virulence. “types” according to their II, Dr. Lancefield’s lab earned capsular the name “The Scotland Yard of produces this protein, which is (similar to her work with Streptococcal Mysteries,” and associated with cross reactivity pneumococcus). Later, was sent thousands of strains of with heart muscle tissue, and is Lancefield was also able to streptococci for analysis and the true causative agent of show that white blood cells study. Dr. Lancefield’s team rheumatic fever. were unable to engulf bacteria diligently worked through these possessing M protein, thus strains and her work is still kept The other antigenic target initially evading the host’s in several volumes of Lancefield discovered was the C immune defense. Furthermore, notebooks, mostly written in her carbohydrate. It quickly became when M protein protection was own hand. Her bibliography apparent that the C carbohydrate overcome by specific comprises more than 50 could be used to distinguish antibodies, the antigenic publications over 60 years. between certain species of reaction was type-specific, streptococci. For example, it meaning that an immune Dr. Lancefield’s accolades include (but are not limited to) president of the Society of indoctrination and with most of egg/bourbon/rum mix. American Bacteriologists, his questions answered—as well Add the light cream with stirring. president of the American as with a collection of cultures Add the sugar to taste with mixing Association of Immunologists, of reference streptococcal (1 pound/batch), then add nutmeg recipient of the American Heart strains and samples of the to taste. Association Achievement relevant antisera.” She has been Award, election to the National a role model for young women Leave standing at least overnight with lid slightly ajar in refrigerator. Academy of Sciences, recipient considering a career in science. Serve after 2-3 weeks in the cold. of honorary degrees from Due to her success in the lab, Rockefeller University and she advanced the role of women , the New as leaders in science. Source: Flora Lichtman, Science Friday, York Academy of Medicine http://sciencefriday.com/blogs/11/29/2012/dr Medal. National and Finally, as a testament to Dr. -rebecca-lancefield-s-eggnog- recipe.html?audience=4 International organizations of Lancefield’s personal character streptococcal study have and generosity, as well as her renamed themselves “The team-building skills, Science Christopher Massey Lancefield Society” in Dr. Friday published her recipe for Santa Maria, CA Lancefield’s honor. Egg Nog, which she made a tradition of preparing with her At 86 years of age, Dr. lab workers before Lancefield died in March of Thanksgiving every year and 1981 at her home in , served at their annual Christmas leaving a significant legacy of party. Reportedly, this tradition scientific findings. She was well continues today in the same lab. known for her helpful attitude towards colleagues and co- We hope you enjoy! workers. Lancefield’s Egg Nog Recipe

1 dozen eggs 1 quart heavy cream 1 quart light cream 1 pint bourbon 1 quart rum nutmeg sugar to taste (1/2 - 3/4 lb)

She freely shared the fruits of her lab’s work and it is said that Beat eggs, add bourbon and rum “a visitor with an interest in slowly with stirring to prevent precipitation of egg . Beat streptococcal problems would heavy cream separately until it leave with a thorough peaks and add to the