Many vaccines containing somatic and secreted antigens of Pseudomonas aeruginosa have been reported. The vaccines containing lipopolysaccharide have been found to provide type-specific protection, but the endotoxin content of these vaccines does not make it feasible to use them in patients who are already debilitated. Outer membrane proteins could be effective as vaccines, as they can be purified free of lipopolysaccharide, and also because they are common to all serotypes of P. aeruginosa. To be effective as a vaccine, such proteins must be immunogenic and accessible from the outside of the intact bacterial cell. In this study, we showed that systemic antibodies were produced frequently to two cell envelope proteins with masses of 58,500 and 37,500 daltons and occasionally to 34,000-dalton protein of P. aeruginosa in cystic fibrosis patients with chronic lung infections. In rabbits immunized with whole, fixed cells of P. aeruginosa, antibodies were also produced against the 58,500-dalton proteins. Thus, the 58,500-dalton cell envelope protein of P. aeruginosa was the only immunogenic protein that was accessible to the immune system when whole, fixed cells were used for immunization. These serum antibodies did not protect the cystic fibrosis patients against further lung infection with P. aeruginosa.
Two commercial kit systems, the API Staph-Ident system (Analytab Products, Inc., Plainview, N.Y.) and the DMS Staph-Trac system (DMS Laboratories, Inc., Flemington, N.J.), were compared with conventional methods for the identification of nine species of coagulase-negative staphylococci. The API Staph-Ident system, a biochemical and chromogenic substrate micromethod, correctly identified 95 of 120 (79.2%) clinical isolates of coagulase-negative staphylococci after 5 h of incubation. The DMS Staph-Trac system, a miniaturized biochemical test system which requires a 24-h incubation period, correctly identified 106 (88.3%) of the same isolates. Both commercial systems were similar in cost and amount of technologist time required to inoculate and read each system. The clinical value of routine species identification of coagulasenegative staphylococci has not yet been established. The decision by clinical laboratories of whether to adopt this practice will be greatly facilitated by the availability of commercial kit systems which are both rapid and accurate.
With the Enterobacteriaceae Plus Biochemical Card, the AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.) is purported to identify members of the family Enterobacteriaceae and seven species of glucose-nonfermenting gramnegative rods: Pseudomonas aeruginosa, P. fluorescens, P. putida, P. maltophilia, P. cepacia, and Acinetobacter calcoaceticus (saccharolytic and non-saccharolytic). The latter capability was examined in this investigation. Of 410 glucosenonfermenting rods included in the identification profile, the AutoMicrobic system correctly identified 366 (89.3%). Of 62 glucose-nonfermenting organisms not included in the identification profile, 41 (66%) were correctly reported as "unidentified organism." The usefulness of the AutoMicrobic system-generated identification probability in establishing criteria for acceptance of identification is discussed.
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