CHARACTERIZATION OF 2 ESCHERICHIA-COLI ISOLATES ASSOCIATED WITH POULTENTERITIS AND MORTALITY SYNDROME

Two colonial types (1 and 2) of Escherichia coli are represented predo minantly in cultures isolated from turkey poults with poult enteritis and mortality syndrome (PEMS). Biotype codes determined using two syst ems (BBL: 36570 and 34560 for colony types 1 and 2, respectively; API- 2OE: 5144572 and 5144512 for colony types 1 and 2, respectively) clear ly establish these organisms as E. coli. These isolates were not clear ly divergent from the general profile for E. coli, but colony type 2 d iffers from colony type 1 with regard to its negative reactions for or nithine decarboxylase and the fermentation of dulcitol, rhamnose, sucr ose, and melibiose, suggesting that it is atypical. Colony type 1 is n onserotypable and nonmotile, whereas colony type 2 is serotyped as O13 6: motile because it has H antigens associated with flagella. Capsular antigens were not found, but thin capsules were seen on cells from bo th colony types in stained preparations. Cultural morphology was diffe rent with colony type 1 having a circular, mucoid, raised morphology a nd colony type 2 having an irregular, flat, rough morphology. Colony t ype 1 has a doubling time at 37 C of about 20 min, whereas colony type 2 doubles in 30 min. Furthermore, colony type 1 is a potent colicin p roducer, but colony type 2 is not a colicin producer. Both E. coli iso lates have resistance profiles for multiple antibiotics. Each strain r esponds to third generation flouroquinalone antibiotics by changing th eir biotypes and become resistant after culturing once in their presen ce. These E. coli are proposed as possible etiological links in the co mplex series of events that take place in poults susceptible to PEMS.