Bacteriologic and Epidemiologic Characteristics of Enterobacter hafniae and Enterobacter liquefaciens

The bacteriology, antibiotic susceptibility, and epidemiology of Enterobacter hafniae and Enterobacter liquefaciens isolated in our laboratory have been reviewed. Gentamicin was the most active agent against both species, followed by kanamycin, chloramphenicol, carbenicillin, and nalidixic acid. Most of the isolates of E. liquefaciens were susceptible to ampicillin and resistant to polymyxin B, while the opposite was true of E. hafniae. Twenty-seven of the 38 isolates were considered to be commensals; the majority originated in the respiratory tract. Eight of the isolates were secondary invaders. Previous administration of semi-synthetic penicillins or cephalosporins was a common feature of patients who acquired either species nosocomially.