In 1972 there were only 11 genera and 26 species in the family Enterobacteriaceae. Today there are 22 genera, 69 species, and 29 biogroups or Enteric Groups. This paper is a review of all of the new organisms. It has a series of differential charts to assist in identification and a large chart with the reactions of 98 different organisms for 47 tests often used in identification. A simplified version of this chart gives the most common species and tests most often used for identification. The sources of the new organisms are listed, and their role in human disease is discussed. Fourteen new groups ofEnterobacteriaceae are described for the first time. These new groups are biochemically distinct from previously described species, biogroups, and Enteric Groups of Enterobacteriaceae. The new groups are Citrobacter amalonaticus biogroup 1, Klebsiella group 47 (indole positive, ornithine positive),

We characterized 13 cultures of the enteric bacterium causing enteric septicemia of catfish by studying their biochemical reactions, deoxyribonucleic hybridizations, and deoxyribonucleic acid guanine-plus-cytosine contents. We confirmed that this bacterium is a new species, which is most closely related to Edwardsiella tarda of the family Enterobacteriaceae. Five strains of the bacterium causing enteric septicemia of catfish were 80% or more related to the type strain, SECFDL GA 77-52 (= CDC 1976-78 = ATCC 33202), in 60°C deoxyribonucleic acid homology reactions. Species level relatedness among the 13 strains which we studied was demonstrated by the more than 80% relatedness in 75°C reactions. The bacterium causing enteric septicemia of catfish was most closely related to E. tarda (56 to 62%) in 60°C reactions. The guanine-plus-cytosine was 53 mol%, as determined by buoyant density centrifugation. We propose the name Edwardsiella ictaluri sp. nov. for the bacterium causing enteric septicemia of catfish.Enteric septicemia of catfish (ESC) is a newly described bacterial disease primarily of cultured channel catfish (Ictalurus punctatus) (9). The causative agent of this disease is a gram-negative, rod-shaped, 0.5-by 1.25-pm, oxidase-negative, peritrichous, fermentative bacterium that has been isolated 26 different times from the kidney tissues of moribund catfish. Biochemically, this organism is most similar to Edwardsiella tarda but differs from E. tarda in several key diagnostic characteristics (1).ESC was fist detected in 1976. Although not always consistent, the clinical signs of this disease in I. punctatus are typical of the acute bacterial septicemias caused by E. tarda, Aeromonas hydrophila, and Pseudomonas fluorescens ( 5 , 11).ESC presently constitutes an economic threat to catfish farmers in Alabama, Georgia, and Mississippi. The pathogenicity of the ESC bacterium to species of fish other than catfish has not been demonstrated, although it has been isolated from channel catfish (I. punctatus), white catfish (Ictalurus catus), and brown bullhead (Ictalurus nebulosus). In this paper we characterize, classify, and name the ESC bacterium.

The name Escherichia v'ulneris sp. nov. (formerly called Alma group 1 and Enteric group 1 by the Centers for Disease Control and API group 2 by Analytab Products, Inc.) is proposed for a group of isolates from the United States and Canada, 74% of which were from human wounds. E. v'uilneris is a gram-negative, oxidase-negative, fermentative, motile rod with the characteristics of the family Enterobacteriaceae. Biochemical reactions characteristic of 61 E. illtneris strains were positive tests for methyl red, malonate, and lysine decarboxylase; a delayed positive test for arginine dihydrolase; acid production from D-mannitol, Larabinose, raffinose, L-rhamnose, D-xylose, trehalose, cellobiose, and melibiose; negative tests for Voges-Proskauer, indole, urea, H,S, citrate, ornithine decarboxylase, phenylalanine deaminase, and DNase; and no acid from dulcitol, adonitol, myo-inositol, and D-sorbitol. Two-thirds of the strains produced yellow pigment. Most strains gave negative or delayed positive reactions in tests for lactose, sucrose, and KCN. The E. vulneris strains tested were resistant to

T h e a u t h o r s g i v e a f u l l d e s c r i p t i o n o f a n e w s p e c i e s a n d g e n u s t o b e i n c l u d e d i n t h e f a m i l y E n t e r o b a c t e r i a c e a e . T h e g e n e r i c n a m e E d w a r d s i e l l a ( E w i n g a n d M c W h o r t e r ) a n d t h e s p e c i e s n a m e E d w a r d s i e l l a t a r d a a r e s u g g e s t e d f o r u s e i n c o n n e c t i o n w i t h t h e b a ct e r i a d e s c r i b e d .The purpose of this paper is to provide a description of the biochemical reactions given by a group of cultures that have been collected and studied in these laboratories since e a r l y i n 1959, and to r e p o r t the r e s u l t s of p r e l i m i n a r y s e r ological investigations.A s e a r c h of the literature did not reveal a description of a microorganism that closely r esembled m e m b e r s of the new group, which i s r e f e r r e d to simply as "bacterium 1483-59,"The word "new" i s not used without reservation, since it seemed probable that the bacteria have been isolated in the past. F u r t h e r , we a r e informed by D r , R. Sakazaki, of the National Institute of Health, Tokyo, (personal communication, 1964) that he p r esented a paper entitled "The New Group of Enterobacteriaceae, the Asakusa Group" a t the 1962 meeting of the Japan Bacteriological Society and that a s u m m a r y of the presentation (Japanese text) was published (Sakazaki, 1962). Dr.Sakazaki v e r y kindly furnished the authors with a t r a n s lation of the above-mentioned a b s t r a c t . F r o m this it appeared that the majority of the cultures w e r e isolated f r o m snakes and that the s t r a i n s described were s i m i l a r to those reported herein, although t h e r e were a few differences in the biochemical reactions obtained (v. id.). Also King and Adler (1964)described the isolation of a culture of bacterium 1483-59, which they labe led the "Bartho Lomew group." Their

Variation in the chromosomal genomes of newport) in isolates of clones belonging to several evolutionary lineages, some of which are distantly related, suggests that the horizontal transfer and recombination of chromosomal genes mediating expression of cell-surface antigens has been a significant process in the evolution of the salmonellae. Two divergent clone clusters of S. derby differ in the relative frequency with which they cause disease in birds versus mammals, and two major lineages of S. newport differ in the frequency with which their clones are associated with disease in humans versus animals.