Evaluation of Sellers’ Medium for the Differentiation of Gram-Negative Bacteria

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ANTIBIOTICS seem to have altered considerably the patterns of microbial infections1,2 in humans. Within the last two decades the literature has clearly shown the importance and the increasing incidence of infections caused by various gram-negative bacteria.3 The most important of these are Pseudomonas, Proteus, Alcaligenes, Citrobacter, Escherichia, and Aerobacter which have been variously associated with enteritis,4 endocarditis,5 bacteremia,6,7 meningitis,8 and septicemia.9 Particular interest is being directed toward the group of gram-negative coccobacilli included in the Mima-Herellea group by De Bord,10 and by Daly, Postic, and Kass.11 The pathogenicity of some of the organisms has been assessed on the basis of their ability to produce specific enzymes.12–14 The coccobacilliary group includes Mima polymorpha, Herellea vaginicola, and species of Colloides, which have been associated with conjunctivitis and vaginitis,11 urethritis,15 endocarditis,16,17 meningitis,18 and synovitis.19 In addition to these organisms the bacteria referred to as Bacterium anitratum also belong to this group. Its relationship to Herellea vaginicola is uncertain. The entire group of organisms has been referred to as autochthonous (indigenous to the host) bacteria, since they are usual commensals of the gastrointestinal, respiratory and genital tracts.11

The differentiation of many of these organisms requires time-consuming methods involving the use of a number of special differential media and biochemical tests. Sellers20,21 recently described a medium for the differentiation of some of these organisms that he has somewhat loosely referred to as “gram-negative, nonfermenting bacilli of medical interest.” The group includes Mima polymorpha, Herellea vaginicola, Bacterium anitratum, Pseudomonas aeruginosa, and Alcaligenes fecalis. To our. . .



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