Typing of Enterobacter spp. by bacteriocin susceptibility and its use in epidemiological analysis

Abstract

A practicable system was devised for epidemiological typing of E. cloacae isolates by their patterns of susceptibility to bacteriocins. A set of 8 bacteriocin-producing strains was grown on tryptic soy agar plates for 16 h. After removal of the producer lawn, the isolates to be typed were inoculated on the agar media by a multipoint inoculator. After a second 16 h period of incubation, the strains were classified into bacteriocin types according to the patterns of growth inhibition. Typability of 134 clinical isolates was 96.3%. Only 11 (8.2%) of the isolates fell into the largest group. Repeat testing of isolates from the same patients within 2 mo. gave identical bacteriocin types. E. agglomerans and E. aerogenes are also typable by this method.