Comparison of Meritec-Strep with Streptex for direct colony grouping of beta-hemolytic streptococci from primary isolation and subculture plates. 1988

J R Hamilton
Clinical Pathology Department, Santa Clara Valley Medical Center, San Jose, California 95128.

Meritec-Strep (Meridian Diagnostics, Inc., Cincinnati, Ohio) a coagglutination method, was compared with Streptex (Wellcome Diagnostics, Research Triangle Park, N.C.), a latex agglutination method, for the identification of beta-hemolytic streptococcal groups A, B, C, F, and G by the direct colony method. A total of 124 beta-hemolytic streptococcal isolates were tested, which included 77 from group A, 15 from group B, 10 from group C, 1 from group F, and 21 from group G. All were tested from subculture, and 74 (60%) were also tested from primary isolation plates. For Meritec-Strep, usually one colony was directly applied to the reaction card for testing each grouping reagent, while for Streptex, five colonies were tested after a 1-h extraction process. Complete agreement was obtained for all isolates tested from subculture with the kits. From primary isolation plates, Meritec-Strep correctly identified 97.3% of the isolates compared with 94.6% correctly identified for Streptex. Meritec-Strep produced a false-negative for one group A isolate and positive reactions for group A and F reagents with another group A isolate. A diphtheroid contaminant caused the positive group F reaction. Streptex produced false-negative results for one group A and three group C isolates. Most positive reactions were strong and rapid (less than 30 s) for both kits. The negative test control provided in the individual group A and B kits was nonreactive for all isolates. Meritec-Strep accurately identified isolated colonies of beta-hemolytic streptococci on primary isolation and subculture plates. It provided faster results than Streptex by eliminating the time and manipulation of antigen extraction and needed fewer colonies when individual group A or B reagents were used.

UI MeSH Term Description Entries
D007841 Latex Fixation Tests Passive agglutination tests in which antigen is adsorbed onto latex particles which then clump in the presence of antibody specific for the adsorbed antigen. (From Stedman, 26th ed) Latex Agglutination Tests,Agglutination Test, Latex,Agglutination Tests, Latex,Fixation Test, Latex,Fixation Tests, Latex,Latex Agglutination Test,Latex Fixation Test,Test, Latex Agglutination,Test, Latex Fixation,Tests, Latex Agglutination,Tests, Latex Fixation
D010614 Pharynx A funnel-shaped fibromuscular tube that conducts food to the ESOPHAGUS, and air to the LARYNX and LUNGS. It is located posterior to the NASAL CAVITY; ORAL CAVITY; and LARYNX, and extends from the SKULL BASE to the inferior border of the CRICOID CARTILAGE anteriorly and to the inferior border of the C6 vertebra posteriorly. It is divided into the NASOPHARYNX; OROPHARYNX; and HYPOPHARYNX (laryngopharynx). Throat,Pharynxs,Throats
D011237 Predictive Value of Tests In screening and diagnostic tests, the probability that a person with a positive test is a true positive (i.e., has the disease), is referred to as the predictive value of a positive test; whereas, the predictive value of a negative test is the probability that the person with a negative test does not have the disease. Predictive value is related to the sensitivity and specificity of the test. Negative Predictive Value,Positive Predictive Value,Predictive Value Of Test,Predictive Values Of Tests,Negative Predictive Values,Positive Predictive Values,Predictive Value, Negative,Predictive Value, Positive
D011933 Reagent Kits, Diagnostic Commercially prepared reagent sets, with accessory devices, containing all of the major components and literature necessary to perform one or more designated diagnostic tests or procedures. They may be for laboratory or personal use. Diagnostic Reagent Kits,Diagnostic Reagents and Test Kits,Diagnostic Test Kits,In Vitro Diagnostic Device,In Vitro Diagnostic Devices,In Vitro Diagnostic Medical Device,In Vitro Diagnostic Medical Devices,Kits, Diagnostic Reagent,Diagnostic Reagent Kit,Diagnostic Test Kit,Kit, Diagnostic Reagent,Kit, Diagnostic Test,Kits, Diagnostic Test,Reagent Kit, Diagnostic,Test Kit, Diagnostic,Test Kits, Diagnostic
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000372 Agglutination Tests Tests that are dependent on the clumping of cells, microorganisms, or particles when mixed with specific antiserum. (From Stedman, 26th ed) Agglutination Test,Test, Agglutination,Tests, Agglutination
D013290 Streptococcal Infections Infections with bacteria of the genus STREPTOCOCCUS. Group A Strep Infection,Group A Streptococcal Infection,Group A Streptococcal Infections,Group B Strep Infection,Group B Streptococcal Infection,Group B Streptococcal Infections,Infections, Streptococcal,Infection, Streptococcal,Streptococcal Infection
D013291 Streptococcus A genus of gram-positive, coccoid bacteria whose organisms occur in pairs or chains. No endospores are produced. Many species exist as commensals or parasites on man or animals with some being highly pathogenic. A few species are saprophytes and occur in the natural environment.
D014946 Wound Infection Invasion of a wound by pathogenic microorganisms. Infection, Wound,Infections, Wound,Wound Infections

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